The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Orthodontic resins /certified fixed orthodontic courses by Indian dental acad...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
Composite resins1/ rotary endodontic courses by indian dental academyIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Description :
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Composites in dentistry /certified fixed orthodontic courses by Indian denta...Indian dental academy
Welcome to Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients
State of the art comprehensive training-Faculty of world wide repute &Very affordable.
Resins in orthodon 2 /certified fixed orthodontic courses by Indian dental ac...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Orthodontic resins /certified fixed orthodontic courses by Indian dental acad...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
Composite resins1/ rotary endodontic courses by indian dental academyIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Description :
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Composites in dentistry /certified fixed orthodontic courses by Indian denta...Indian dental academy
Welcome to Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients
State of the art comprehensive training-Faculty of world wide repute &Very affordable.
Resins in orthodon 2 /certified fixed orthodontic courses by Indian dental ac...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Recent advances in dental composites include materials with improved properties such as reduced polymerization shrinkage, increased strength and wear resistance, enhanced aesthetics, and additional therapeutic benefits. New composite formulations incorporate multi-methacrylate monomers, ultrarapid mono-methacrylates, and acidic monomers to address shrinkage. Novel polymerization mechanisms like polymerization-induced phase separation, thiol-ene photopolymerization, and hybrid/ring-opening polymerization aim to reduce shrinkage stress. Improved fillers and surface treatments enhance mechanical properties. New composite types have been introduced, including flowables, bulk-fill, packables, and gingival-shaded materials. Overall, ongoing research focuses on developing dental compos
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
This document provides an overview of dental composites, including their chemistry, materials, filler types, bonding agents, curing methods, classifications, and clinical applications and techniques. Key points include:
- Dental composites consist of a resin matrix and filler materials, along with coupling agents to bond resin to fillers. They are polymerized through heat, chemical, or photochemical initiation.
- Fillers improve physical properties but characteristics depend on filler type, size, shape, and load. Larger and smaller filler particles reduce shrinkage.
- Bonding agents like silanes chemically coat fillers to improve strength, but can degrade with moisture.
- Composites are classified by initiation method
The document appears to be discussing different types of aesthetic restorative materials used in dentistry, including unfilled resin, filled resin composites, glass ionomers, ceramics, and silicate cements. It focuses on describing the composition, properties, advantages, and disadvantages of filled resin composites. It explains that composites contain inorganic filler particles suspended in an organic resin matrix, and that the amount and size of filler impacts the material's properties. Larger filler leads to better strength and durability, while smaller filler provides better aesthetics and surface quality.
Resin composites are dental restorative materials made of an organic resin matrix and inorganic filler particles. They contain monomers like bis-GMA that polymerize to form the matrix. Fillers like silica improve properties and radiopacity. Coupling agents bond fillers to the matrix. Composites are classified by filler size and polymerization method. Proper placement techniques and acid etching improve bonding to tooth structure. While esthetic and conservative, composites also have limitations like polymerization shrinkage, sensitivity, and wear over time.
This document provides an overview of composite resins, including:
1. Definitions, classifications, compositions, and recent advances in composite resins such as ceromers, compomers, and fiber-reinforced composites.
2. The resin matrix phase includes monomers like Bis-GMA and fillers like quartz, borosilicate glass, and ceramic particles.
3. Coupling agents are used to attach the inorganic filler particles to the resin matrix phase to improve the mechanical properties of composite resins.
Indian Dental Academy: will be one of the most relevant and exciting
training center with best faculty and flexible training programs
for dental professionals who wish to advance in their dental
practice,Offers certified courses in Dental
implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic
Dentistry, Periodontics and General Dentistry.
Synthetic Resins used in ProsthodonticsKelly Norton
The document discusses synthetic resins used in prosthodontics. It provides a brief history of dentures from ancient bone and wood dentures to modern resins like polymethyl methacrylate. Ideal requirements for dental resins include biocompatibility, adequate physical properties, and ease of manipulation. The basic nature of polymers is explained including types of spatial arrangements and polymerization techniques like addition and condensation polymerization. Common denture base resins are classified and compression molding technique is summarized in 3 main steps: stone mold preparation, dewaxing, and resin manipulation.
This document discusses the specifications and properties of dental composite materials according to ADA specification no. 27. It outlines the major and minor constituents of composites including the resin matrix, filler particles, and coupling agents. It also describes the advantages and disadvantages of composites, their mechanical properties, modes of curing, and factors that affect properties such as polymerization shrinkage, thermal expansion, water sorption, and radiopacity.
Description :
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This document discusses dental composites and is divided into two parts. Part I covers an introduction to composites, their classification based on filler particle size, composition, and factors that affect light curing. It also discusses direct posterior composites and posterior pit and fissure sealants. Composites are classified as microfilled, small particle, hybrid, and macrofilled based on filler particle size. They contain resin matrix, filler particles, coupling agents, initiators, inhibitors, and optical modifiers. Factors like light intensity, distance, and thickness can impact curing of composites.
The document discusses heat cure acrylic denture base resins. It provides background on the development of denture base materials over time. Polymethyl methacrylate (PMMA) was introduced in 1937 and remains the material of choice due to its superior esthetics, ease of processing, accurate fit, and use with inexpensive equipment. The document describes the composition, chemical basis of polymerization, manipulation techniques including compression molding and injection molding, and physical properties of heat cure acrylic resins. It also compares heat cure resins to self-cure resins and discusses requirements versus clinical performance as well as recent advances in the material.
Composites /certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Acrylic resin is a type of plastic produced from a combination of methacrylic acid, acrylic acid, and other compounds. It has properties like high transparency, weather resistance, workability, water and chemical resistance, transparency, hardness, and heat resistance. There are different types of acrylic including epoxy resin and casting resin. Acrylic can be classified based on its monomers (homopolymer, terpolymer, copolymer), spatial structure (linear, cross, branched), or behavior in heat (thermoplastic, thermoset). Acrylic comes in powder or liquid form and is used as a dental cement for restoring teeth as well as in mouthpieces, crowns, dentures
Denture base resins are typically made of polymethyl methacrylate (PMMA) and are fabricated using heat- or chemically- activated resins. PMMA denture bases are hard, transparent, and resistant to discoloration. The resins undergo polymerization shrinkage of around 21% as the monomer methyl methacrylate forms chains and evaporates slightly during processing. Proper mixing and compression molding can minimize porosity and achieve adequate polymerization for optimal denture fit and function.
Composite resin is a combination of two or more chemically different materials that results in properties superior to the individual components. It consists of a resin matrix and filler materials. Over time, developments have included the introduction of silane coupling agents, light-cured composites, microfilled composites, and nanofilled composites. Composites are classified based on properties such as filler size and distribution, polymerization method, presentation, consistency, and intended use. Proper use of composites for dental restorations requires understanding of factors like smile design, tooth color, shape, and position.
The document discusses various materials used for denture bases, including cellulose and phenol-formaldehyde, but notes that acrylic resin (polymethyl methacrylate or PMMA) is now the preferred material. It outlines the ideal requirements for denture base materials and describes the different types of PMMA resins, including heat cure, cold cure, light cure, and microwave cured. The document provides details on the composition, mixing, and curing of heat cure PMMA resin and compares its properties to cold cure resin. It also briefly discusses light cure, microwave cured, and injection molded resins.
This document provides information on denture base resins. It defines denture bases and materials, and classifies resins according to ISO 1567 and usage. The main types discussed are heat-cured, chemically-cured, light-cured, and microwave-cured resins. The document outlines the composition, polymerization process, properties, and cytotoxicity of these resins. It also discusses ideal requirements, water absorption, strength, and cleaning of denture bases.
Epoxy resins are thermosetting polymers that are supplied as liquids, solids, or solutions and can be hardened using additives. They have a wide variety of applications including coatings, composites, electronics, and adhesives due to their high strength to weight ratio. Common types of epoxy resins include bisphenol A, bisphenol F, novolac, aliphatic, and glycidylamine resins. Epoxy resins are cured through cross-linking reactions with hardeners like amines, anhydrides, or phenalkamines to form rigid thermoset polymers with improved mechanical and thermal properties.
Orthodontic adhesives have progressed through five generations, moving from unfilled acrylic resins to modern light-cured resin composites. First generation adhesives were unfilled poly(methyl methacrylate) that caused enamel damage. Second generation used UV light activation but had radiation hazards. Third generation introduced two-paste filler systems like Concise. Fourth generation were "no-mix" but had inhomogeneous curing. Current fifth generation utilize visible light curing for safer, deeper curing without diminishing over time.
Orthodontic adhesives have progressed through 5 generations, moving from unfilled acrylic resins to modern light-cured and dual-cured resin composites. Early generations used self-curing chemistries that were technique sensitive and produced low bond strengths. Current adhesives are predominantly dimethacrylate-based resin composites cured by light, containing fillers for strength and coupling agents to bond fillers to the resin matrix. Light curing provides rapid and uniform curing without technique sensitivity, allowing earlier placement of wires. Newer adhesives continue to be developed with properties like fluoride release and reduced cytotoxicity.
Recent advances in dental composites include materials with improved properties such as reduced polymerization shrinkage, increased strength and wear resistance, enhanced aesthetics, and additional therapeutic benefits. New composite formulations incorporate multi-methacrylate monomers, ultrarapid mono-methacrylates, and acidic monomers to address shrinkage. Novel polymerization mechanisms like polymerization-induced phase separation, thiol-ene photopolymerization, and hybrid/ring-opening polymerization aim to reduce shrinkage stress. Improved fillers and surface treatments enhance mechanical properties. New composite types have been introduced, including flowables, bulk-fill, packables, and gingival-shaded materials. Overall, ongoing research focuses on developing dental compos
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
This document provides an overview of dental composites, including their chemistry, materials, filler types, bonding agents, curing methods, classifications, and clinical applications and techniques. Key points include:
- Dental composites consist of a resin matrix and filler materials, along with coupling agents to bond resin to fillers. They are polymerized through heat, chemical, or photochemical initiation.
- Fillers improve physical properties but characteristics depend on filler type, size, shape, and load. Larger and smaller filler particles reduce shrinkage.
- Bonding agents like silanes chemically coat fillers to improve strength, but can degrade with moisture.
- Composites are classified by initiation method
The document appears to be discussing different types of aesthetic restorative materials used in dentistry, including unfilled resin, filled resin composites, glass ionomers, ceramics, and silicate cements. It focuses on describing the composition, properties, advantages, and disadvantages of filled resin composites. It explains that composites contain inorganic filler particles suspended in an organic resin matrix, and that the amount and size of filler impacts the material's properties. Larger filler leads to better strength and durability, while smaller filler provides better aesthetics and surface quality.
Resin composites are dental restorative materials made of an organic resin matrix and inorganic filler particles. They contain monomers like bis-GMA that polymerize to form the matrix. Fillers like silica improve properties and radiopacity. Coupling agents bond fillers to the matrix. Composites are classified by filler size and polymerization method. Proper placement techniques and acid etching improve bonding to tooth structure. While esthetic and conservative, composites also have limitations like polymerization shrinkage, sensitivity, and wear over time.
This document provides an overview of composite resins, including:
1. Definitions, classifications, compositions, and recent advances in composite resins such as ceromers, compomers, and fiber-reinforced composites.
2. The resin matrix phase includes monomers like Bis-GMA and fillers like quartz, borosilicate glass, and ceramic particles.
3. Coupling agents are used to attach the inorganic filler particles to the resin matrix phase to improve the mechanical properties of composite resins.
Indian Dental Academy: will be one of the most relevant and exciting
training center with best faculty and flexible training programs
for dental professionals who wish to advance in their dental
practice,Offers certified courses in Dental
implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic
Dentistry, Periodontics and General Dentistry.
Synthetic Resins used in ProsthodonticsKelly Norton
The document discusses synthetic resins used in prosthodontics. It provides a brief history of dentures from ancient bone and wood dentures to modern resins like polymethyl methacrylate. Ideal requirements for dental resins include biocompatibility, adequate physical properties, and ease of manipulation. The basic nature of polymers is explained including types of spatial arrangements and polymerization techniques like addition and condensation polymerization. Common denture base resins are classified and compression molding technique is summarized in 3 main steps: stone mold preparation, dewaxing, and resin manipulation.
This document discusses the specifications and properties of dental composite materials according to ADA specification no. 27. It outlines the major and minor constituents of composites including the resin matrix, filler particles, and coupling agents. It also describes the advantages and disadvantages of composites, their mechanical properties, modes of curing, and factors that affect properties such as polymerization shrinkage, thermal expansion, water sorption, and radiopacity.
Description :
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This document discusses dental composites and is divided into two parts. Part I covers an introduction to composites, their classification based on filler particle size, composition, and factors that affect light curing. It also discusses direct posterior composites and posterior pit and fissure sealants. Composites are classified as microfilled, small particle, hybrid, and macrofilled based on filler particle size. They contain resin matrix, filler particles, coupling agents, initiators, inhibitors, and optical modifiers. Factors like light intensity, distance, and thickness can impact curing of composites.
The document discusses heat cure acrylic denture base resins. It provides background on the development of denture base materials over time. Polymethyl methacrylate (PMMA) was introduced in 1937 and remains the material of choice due to its superior esthetics, ease of processing, accurate fit, and use with inexpensive equipment. The document describes the composition, chemical basis of polymerization, manipulation techniques including compression molding and injection molding, and physical properties of heat cure acrylic resins. It also compares heat cure resins to self-cure resins and discusses requirements versus clinical performance as well as recent advances in the material.
Composites /certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Acrylic resin is a type of plastic produced from a combination of methacrylic acid, acrylic acid, and other compounds. It has properties like high transparency, weather resistance, workability, water and chemical resistance, transparency, hardness, and heat resistance. There are different types of acrylic including epoxy resin and casting resin. Acrylic can be classified based on its monomers (homopolymer, terpolymer, copolymer), spatial structure (linear, cross, branched), or behavior in heat (thermoplastic, thermoset). Acrylic comes in powder or liquid form and is used as a dental cement for restoring teeth as well as in mouthpieces, crowns, dentures
Denture base resins are typically made of polymethyl methacrylate (PMMA) and are fabricated using heat- or chemically- activated resins. PMMA denture bases are hard, transparent, and resistant to discoloration. The resins undergo polymerization shrinkage of around 21% as the monomer methyl methacrylate forms chains and evaporates slightly during processing. Proper mixing and compression molding can minimize porosity and achieve adequate polymerization for optimal denture fit and function.
Composite resin is a combination of two or more chemically different materials that results in properties superior to the individual components. It consists of a resin matrix and filler materials. Over time, developments have included the introduction of silane coupling agents, light-cured composites, microfilled composites, and nanofilled composites. Composites are classified based on properties such as filler size and distribution, polymerization method, presentation, consistency, and intended use. Proper use of composites for dental restorations requires understanding of factors like smile design, tooth color, shape, and position.
The document discusses various materials used for denture bases, including cellulose and phenol-formaldehyde, but notes that acrylic resin (polymethyl methacrylate or PMMA) is now the preferred material. It outlines the ideal requirements for denture base materials and describes the different types of PMMA resins, including heat cure, cold cure, light cure, and microwave cured. The document provides details on the composition, mixing, and curing of heat cure PMMA resin and compares its properties to cold cure resin. It also briefly discusses light cure, microwave cured, and injection molded resins.
This document provides information on denture base resins. It defines denture bases and materials, and classifies resins according to ISO 1567 and usage. The main types discussed are heat-cured, chemically-cured, light-cured, and microwave-cured resins. The document outlines the composition, polymerization process, properties, and cytotoxicity of these resins. It also discusses ideal requirements, water absorption, strength, and cleaning of denture bases.
Epoxy resins are thermosetting polymers that are supplied as liquids, solids, or solutions and can be hardened using additives. They have a wide variety of applications including coatings, composites, electronics, and adhesives due to their high strength to weight ratio. Common types of epoxy resins include bisphenol A, bisphenol F, novolac, aliphatic, and glycidylamine resins. Epoxy resins are cured through cross-linking reactions with hardeners like amines, anhydrides, or phenalkamines to form rigid thermoset polymers with improved mechanical and thermal properties.
Orthodontic adhesives have progressed through five generations, moving from unfilled acrylic resins to modern light-cured resin composites. First generation adhesives were unfilled poly(methyl methacrylate) that caused enamel damage. Second generation used UV light activation but had radiation hazards. Third generation introduced two-paste filler systems like Concise. Fourth generation were "no-mix" but had inhomogeneous curing. Current fifth generation utilize visible light curing for safer, deeper curing without diminishing over time.
Orthodontic adhesives have progressed through 5 generations, moving from unfilled acrylic resins to modern light-cured and dual-cured resin composites. Early generations used self-curing chemistries that were technique sensitive and produced low bond strengths. Current adhesives are predominantly dimethacrylate-based resin composites cured by light, containing fillers for strength and coupling agents to bond fillers to the resin matrix. Light curing provides rapid and uniform curing without technique sensitivity, allowing earlier placement of wires. Newer adhesives continue to be developed with properties like fluoride release and reduced cytotoxicity.
This document provides an overview of composite resin materials used in dental restorations. It defines composite resin as a compound of two or more materials with superior properties to the individual components. Composite resins are classified based on filler size, percentage, resin type, viscosity, and curing method. The document outlines the composition of composite resins including resin matrix, filler particles, coupling agents, and initiators. It discusses advantages like esthetics and disadvantages like polymerization shrinkage. Properties like coefficient of thermal expansion, wear resistance, water absorption, and mechanical properties are also covered.
Dental composite /certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Composite dental restorations represent a unique class of biomaterials with severe restrictions on biocompatibility, curing behaviour, aesthetics, and ultimate material properties. These materials are presently limited by shrinkage and polymerization-induced shrinkage stress, limited toughness, the presence of unreacted monomer that remains following the polymerization, and several other factors. Fortunately, these materials have been the focus of a great deal of research in recent years with the goal of improving restoration performance by changing the initiation system, monomers, and fillers and their coupling agents, and by developing novel polymerization strategies.
Resin composites are used to replace missing tooth structure and modify tooth color. They consist of resin matrix, filler particles, and coupling agents. Composites are classified based on filler size and amount, curing method, and fabrication technique. They have properties like thermal expansion similar to enamel, radiopacity from fillers, and bond to tooth structure. Composites are indicated for fillings, veneers, and splinting but require proper technique due to polymerization shrinkage. Advances include ceromers, smart composites, and nanocomposites to better mimic natural teeth.
Resin based composites(Recent Advances)Taduri Vivek
This document provides an overview of dental composites, including their history, classification, composition, properties, and recent developments. It discusses the key components of composites such as the resin matrix, fillers, coupling agents, and photoinitiators. It also summarizes the different types of composites based on particle size, polymerization method, and other characteristics. Recent innovations in composites include antibacterial, flowable, packable, compomers, and fiber-reinforced formulations.
this presentation includes details about composite resins which are tooth colored filling materials used in dentistry. it also includes various recent advances in this field.
Dr. Mayank Nahta presented on dental composites. Composites are polymers reinforced with filler particles that are bound together. Dr. Ray Bowen developed the first dental composite in 1962 using Bis-GMA resin and glass/quartz fillers. Composites are used for restorations, veneers, cores, and more. They are classified based on properties like filler size, composition, and curing method. Composites provide strength, polishability, aesthetics, and more depending on their formulation. Developments include microfilled, small particle, hybrid, and flowable composites to optimize properties.
Acrylic resin was introduced to dentistry in 1936 and received a great response from the dental professionals such that by 1946, 98% of all denture were made with methyl methacrylate polymer or copolymer.
Prior to 1940 vulcanite was the most widely used denture base resin. This is highly cross linked natural rubber which was difficult to pigment and tended to become unhygienic due to the uptake of saliva.
The document provides an overview of denture base resins including their definition, history, classification, key ingredients, and properties. It discusses the early use of materials like ivory, bone, and porcelain for dentures and the later development of vulcanite in the 1840s as the first affordable and workable material. Polymethyl methacrylate (PMMA) was introduced in the 1930s and became the standard material by 1946, providing improved properties over previous materials. The document outlines the polymerization process and ideal requirements for denture base resins based on biocompatibility, durability, and other factors. Heat-cured PMMA denture base resin is currently the most widely used material.
This document discusses denture base resins. It provides a brief history of denture materials from ancient Egypt to modern times. Key definitions are provided, including classifications of denture base resins. Ideal requirements and properties of denture base materials are outlined. Stages of polymerization and manipulation of the resins are described. Recent advancements and a literature review are mentioned.
Lect. 3th stage tooth color restoration-composite -20181Amir Hamde
The document summarizes tooth color restorations (composite fillings). It discusses the history and development of composite materials from silicates in the 1870s to modern nanofill composites. Composite is made of an organic resin matrix and inorganic filler particles. The resin is usually bis-GMA and the filler is glass or silica coupled together with silane. Composite provides strength and aesthetics but also has disadvantages like polymerization shrinkage. Proper placement technique helps maximize strengths and minimize risks.
This document discusses dental composites, which are used for dental restorations. It describes the components of composites, including the matrix, fillers, and coupling agents. It explains the types of fillers and their purposes. It also discusses the different types of composites based on particle size, including microfilled, small-particle filled, hybrid, packable, and flowable composites. The document outlines the polymerization process and classifications of composites according to curing system and particle size. Advantages and applications of composites are provided. Considerations for bonding composites to enamel and dentin are also summarized.
Lect. 3th stage tooth color restoration-composite part 2-20181Amir Hamde
The document discusses tooth color restorations and composite materials. It provides a history of composite development beginning in 1871 with silicates and progressing to modern nanofill composites. Key components of composites include the resin matrix such as Bis-GMA, filler particles, and silane coupling agents. Ideal properties and composition of composites are outlined. Steps for placing composites are summarized, including isolation, etching, bonding, and layering/curing techniques. Sources of polymerization shrinkage and methods to reduce it are also described.
Effect of Microwave Disinfection on Acrylic Denture Base Materialsassem awad
This document summarizes the aim and methods of a study comparing microwave-cured glass fiber-reinforced acrylic resin to conventional heat-cured acrylic resin. The study measured dimensional changes, impact strength, flexural strength, and hardness of specimens made from each resin, both before and after repeated microwave disinfection treatments. Key findings were that microwave disinfection did not affect dimensional changes, glass fiber-reinforced resin showed higher flexural strength both before and after disinfection, and hardness of conventional resin decreased after disinfection while reinforced resin hardness remained stable. The study concluded microwave disinfection is a simple method for denture disinfection and further research is needed on fiber reinforcement and its effects.
This document provides an overview of dental composite materials. It begins with an introduction and then discusses the history, definitions, indications, advantages, disadvantages, and classifications of composites. It describes the composition of composites including the resin matrix, inorganic fillers, and coupling agents. Different types of composites are explained such as traditional composites, small particle composites, microfilled composites, hybrid composites, and nanofilled composites. Recent advances like flowable composites, packable composites, antibacterial composites, nanocomposites, ormocers, compomers, and smart composites are also summarized.
This document discusses indirect composite restorations such as inlays and onlays. It begins by defining these terms and discussing indications, contraindications, and materials used. It then covers different classification systems for indirect composites based on fabrication method, curing method, and generation. Various commercial composite systems are described. The document discusses advantages like improved physical properties over direct composites, as well as disadvantages like increased time and cost. Fabrication techniques include direct, semidirect, and indirect methods. Steps for cavity preparation and cementation of indirect composites are outlined.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all
aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Similar to Orthodontic resin /certified fixed orthodontic courses by Indian dental academy (20)
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Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals
who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry,
Periodontics and General Dentistry.
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
I –Aligners are made with FDA approved transparent thermoplastic materials using 3D scanning, 3D Printing and finally Trays with Pressure vacuum formers.
Dear Doctor,
Indian Dental Academy Now offers comprehensive online Orthodontics course.
Course includes:
1.whiteboard lecture presentations
2.Case Discussions
3.with hundreds of pictures.
4.Demo on Models
5.Demo on Patients
6. subtitles in your own language
12 months unlimited access and support @350 USD only.
For Demo please visit :www.idalectures.com/preview/
For more details visit: www.idalectures.com
Please contact us for any clarifications:
idalectures@gmail.com
indiandentalacademy@gmail.com
Thanks & Regards
Indian Dental Academy
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Indian Dental Academy
Leader in continuing dental education
www.indiandentalacademy.com
skype:indiandentalacademy
+919248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Diagnosis and treatment planning in completely endntulous arches/dental coursesIndian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Properties of Denture base materials /rotary endodontic coursesIndian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Use of modified tooth forms in complete denture occlusion / dental implant...Indian dental academy
This document discusses dental occlusion concepts and philosophies for complete dentures. It introduces key terms like physiologic occlusion and defines different occlusion schemes like balanced articulation and monoplane articulation. The document discusses advantages and disadvantages of using anatomic versus non-anatomic teeth for complete dentures. It also outlines requirements for maintaining denture stability, such as balanced occlusal contacts and control of horizontal forces. The goal of occlusion for complete dentures is to re-establish the homeostasis of the masticatory system disrupted by edentulism.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This document discusses dental casting investment materials. It describes the three main types of investments - gypsum bonded, phosphate bonded, and ethyl silicate bonded investments. For gypsum bonded investments specifically, it details their classification, composition including the roles of gypsum, silica, and modifiers, setting time, normal and hygroscopic setting expansion, and thermal expansion. It provides information on how the properties of gypsum bonded investments are affected by their composition. The document serves as a comprehensive overview of dental casting investment materials.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Local Advanced Lung Cancer: Artificial Intelligence, Synergetics, Complex Sys...Oleg Kshivets
Overall life span (LS) was 1671.7±1721.6 days and cumulative 5YS reached 62.4%, 10 years – 50.4%, 20 years – 44.6%. 94 LCP lived more than 5 years without cancer (LS=2958.6±1723.6 days), 22 – more than 10 years (LS=5571±1841.8 days). 67 LCP died because of LC (LS=471.9±344 days). AT significantly improved 5YS (68% vs. 53.7%) (P=0.028 by log-rank test). Cox modeling displayed that 5YS of LCP significantly depended on: N0-N12, T3-4, blood cell circuit, cell ratio factors (ratio between cancer cells-CC and blood cells subpopulations), LC cell dynamics, recalcification time, heparin tolerance, prothrombin index, protein, AT, procedure type (P=0.000-0.031). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and N0-12 (rank=1), thrombocytes/CC (rank=2), segmented neutrophils/CC (3), eosinophils/CC (4), erythrocytes/CC (5), healthy cells/CC (6), lymphocytes/CC (7), stick neutrophils/CC (8), leucocytes/CC (9), monocytes/CC (10). Correct prediction of 5YS was 100% by neural networks computing (error=0.000; area under ROC curve=1.0).
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
TEST BANK For Community Health Nursing A Canadian Perspective, 5th Edition by...Donc Test
TEST BANK For Community Health Nursing A Canadian Perspective, 5th Edition by Stamler, Verified Chapters 1 - 33, Complete Newest Version Community Health Nursing A Canadian Perspective, 5th Edition by Stamler, Verified Chapters 1 - 33, Complete Newest Version Community Health Nursing A Canadian Perspective, 5th Edition by Stamler Community Health Nursing A Canadian Perspective, 5th Edition TEST BANK by Stamler Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Pdf Chapters Download Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Pdf Download Stuvia Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Study Guide Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Ebook Download Stuvia Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Questions and Answers Quizlet Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Studocu Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Quizlet Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Pdf Chapters Download Community Health Nursing A Canadian Perspective, 5th Edition Pdf Download Course Hero Community Health Nursing A Canadian Perspective, 5th Edition Answers Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Ebook Download Course hero Community Health Nursing A Canadian Perspective, 5th Edition Questions and Answers Community Health Nursing A Canadian Perspective, 5th Edition Studocu Community Health Nursing A Canadian Perspective, 5th Edition Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Pdf Chapters Download Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Pdf Download Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Study Guide Questions and Answers Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Ebook Download Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Questions Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Studocu Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Stuvia
Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
share - Lions, tigers, AI and health misinformation, oh my!.pptxTina Purnat
• Pitfalls and pivots needed to use AI effectively in public health
• Evidence-based strategies to address health misinformation effectively
• Building trust with communities online and offline
• Equipping health professionals to address questions, concerns and health misinformation
• Assessing risk and mitigating harm from adverse health narratives in communities, health workforce and health system
Integrating Ayurveda into Parkinson’s Management: A Holistic ApproachAyurveda ForAll
Explore the benefits of combining Ayurveda with conventional Parkinson's treatments. Learn how a holistic approach can manage symptoms, enhance well-being, and balance body energies. Discover the steps to safely integrate Ayurvedic practices into your Parkinson’s care plan, including expert guidance on diet, herbal remedies, and lifestyle modifications.
ABDOMINAL TRAUMA in pediatrics part one.drhasanrajab
Abdominal trauma in pediatrics refers to injuries or damage to the abdominal organs in children. It can occur due to various causes such as falls, motor vehicle accidents, sports-related injuries, and physical abuse. Children are more vulnerable to abdominal trauma due to their unique anatomical and physiological characteristics. Signs and symptoms include abdominal pain, tenderness, distension, vomiting, and signs of shock. Diagnosis involves physical examination, imaging studies, and laboratory tests. Management depends on the severity and may involve conservative treatment or surgical intervention. Prevention is crucial in reducing the incidence of abdominal trauma in children.
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptxHolistified Wellness
We’re talking about Vedic Meditation, a form of meditation that has been around for at least 5,000 years. Back then, the people who lived in the Indus Valley, now known as India and Pakistan, practised meditation as a fundamental part of daily life. This knowledge that has given us yoga and Ayurveda, was known as Veda, hence the name Vedic. And though there are some written records, the practice has been passed down verbally from generation to generation.
2. • CONTENTS
• INTRODUCTION
• TYPES OF ADHESIVES
• 1st
-5th
GENERATION
• DUAL CURE RESIN
• THERMOCURED RESIN
• REVIEW OF ARTICLES
• RECENT ADVANCES
• SEP
• CYANOACRYLATE
• FLUORIDE RELEASING ADHESIVE
• ADHESION BOOSTER
• HYDROPHILIC PRIMERS
• APC
• REVIEW OF ARTICLES
• GLASS IONOMER CEMENT
• DYRACT
• REVIEW OF ARTICLES
• ADHESIVES THAT BOND TO CROWNS AND RESTORATIONS
• DEGRADATION OF POLYMER
• LEACHING
• CYTOTOXICITY
• CONCLUSION www.indiandentalacademy.com
3. • The major current category of orthodontic adhesive systems is
based upon resin composites. They consist of three main
components
1. An organic matrix
2. Filler powdered ceramic such as barium aluminoborate silica
glass and
3.Coupling agent.
• Organic Matrix Monomer Components
• The organic matrix is formed by polymerization of an aromatic
or urethane dimethacrylate. It is the chemically active
component. Initially a fluid monomer but is converted into a
rigid polymer by a radical addition reaction.
Bis-GMA is commonly used monomer. It is derived from the
reaction of Bisphenol –A & glycidyl methacrylate.
Its molecular weight is higher than methyl methacrylate, which
helps in reducing polymerization shrinkage. Bis – GMA
monomer is highly viscous fluid, the addition of even a small
amount of filler would produce stiffness that is excessive for
clinical use. www.indiandentalacademy.com
4. • Properties:
• Large molecular size and
• Large chemical structure,
• Advantage :
• It is superior to many monomers of lower molecular mass by
virtue of
• -Lower volatility,
• -Lower polymerization shrinkage ------ more rapid hardening, and
production of a stronger and stiffer resin.
• Since Bis-GMA is highly viscous, viscosity is reduced by adding
monomers, like diethylene glycol dimethacrylate (DEGMA) and
Triethylene glycol dimethacrylate (TEGDMA) . A typical
formulation is 75% Bis-GMA and 25 % TEGDMA
• Another approach is the synthesis of Bis-EMA, a Bis-GMA
analogue that does not have the hydroxyl group in the structure.
• Less sensitive to water than Bis – GMA.
www.indiandentalacademy.com
5. • Polymerization Activation -
• Four types of activation of free radicals are used in
the polymerization of the unsatu-rated methacrylate
groups of the resin composites. Activation of free
radicals is by:
• Self cure (SC)
– Two phase
– One phase ( no mix )
• Light cure (CC)
• Dual cure
• Heat cure
www.indiandentalacademy.com
6. • Extent of Reaction: Degree of Conversion (DC)
• The DC of resin composite materials is the extent to
which carbon double bonds (C = C) of the monomer are
converted into carbon single bonds (C-C) to form
polymers during the polymerization reaction.
C = C C-C
• DC affects the physical properties of composites.
• Inspite of extensive cross-linking on polymerization,
there is considerable residual unsaturation in the final
product ( 25% to 45 % )
• This ranges from 25 % to 45 %, or equivalently the degree
of conversion (DC) ranging from 55% to 75%. .
www.indiandentalacademy.com
7. Unpolymerized resin has deleterious effects on:
• 1. The mechanical properties ----- acts as plasticizer
• 2. Dimensional stability of the restoration.
• 3. Biocompatibility.----- monomer leach in oral environment
What happens to uncured resin?
• 1. The unconverted methacrylate group resides in the polymer
network, either residual monomer or (a majority) as pendant
side chains (PSC).
• 2. A further possibility is a cyclization reaction.
The residual monomer molecules function as plasticizing
agents that can reduce the properties of polymer network and
monomers leach from the composite into the oral
environment.
Hence it is desirable to increase DC in order to produce
stiffer and more durable resins although, for a given
composite shrinkage increases with DC.
www.indiandentalacademy.com
8. Polymerization Shrinkage
• Polymerization shrinkage is
partially explained by a
volumetric decrease arising
from the con-version of van
der Waals bonds into covalent
bonds.
• There is an intrinsic shrinkage
associated with resin
composites and that the time
dependence of this shrinkage
reflects the progress of the
polymerization.
www.indiandentalacademy.com
9. • Dispersed Phase Components
• The filler or reinforcing ceramic phase in the early materials was
a ceramic oxide, such as silica or alumina, or a glass. A high
proportion of ceramic may also reduce polymerization
shrinkage.
Filler selection:
• 1. To reduce the thermal dimensional change of the resin
composite to a value matching that of tooth structure,e.g. fillers
such as lithium aluminum silicate.
• 2. The need for a good refractive index match with the organic
monomer to secure adequate translucence for aesthetic appear-
ance. Radiopaque glasses containing elements such as barium,
strontium, and zinc can be used.
• 3. Large volume of hard filler particles has been incorporated
based on the concept of attainment of high compressive strength
and stiffness and on evidence that abrasion resis-tance improves
as filler content increases and that fine fillers wear more than
coarse particles.
www.indiandentalacademy.com
10. Type of adhesives:
They are classified as
A. Based on the basic bonding system type
1. Acrylic base systems- Poly (methyl methacrylate) systems
2. Diacrylate systems- Bis-GMA systems
3. Glass ionomer systems- 1. Chemical cured
2. Light cured
3. Dual cured
B. Based on fluoride content
1. Fluoride releasing systems
2. Non-fluoride releasing systems
C. Based on the filler content
Lowly filled bonding systems
Highly filled bonding systems.
D. Based on the curing systems
1. Self curing system
2. Light curing system
3. Dual curing system
4. Heat curing system
www.indiandentalacademy.com
11. First Generation Bonding Adhesives
This generation included unfilled acrylic resins and epoxy resins.
The first bonding adhesives used in orthodontics was essential
unfilled poly (methyl methacrylate) anterior dental
restoratives.
The unfilled acrylic resins exist as powder - liquid or paste/paste.
Powder Contains
1. Poly (Methyl methacrylate).
Poly (methyl methacrylate) is a transparent resin of remarkable
clarity it transmits light in the ultraviolet range to a
wavelength of 250 nm
2. Initiator:
Benzoyl peroxide (0.3 to 3%) To start an addition
polymerization process, free radicals must be present. Free
radicals can be generated by activation of monomer molecules
with UV light, visible light, heat or energy transfer.
Initiation period is the time during which molecules of the
initiator become activated forming free radicals that interact
with the monomer molecules.
www.indiandentalacademy.com
12. Liquid :
• Methyl methacrylate monomer
The liquid monomer methyl methacrylate is mixed with
the polymer. Methyl methacrylate is a clear, transparent
liquid at room temperature.
• Cross-linking agent -- Ethylene dimethacrylate (5% or
more)
• Inhibitor: (Monomethyl ether of hydroquinone: (0.006%)
To minimize or prevent spontaneous polymerization of
monomers, inhibitors are added to the resin systems.
These inhibitors have a strong reactivity potential with
free radicals. If a free radical is formed, the inhibitor
reacts with it and controls the reaction.
www.indiandentalacademy.com
13. Unfilled bonding adhesives cause less enamel damage and are
indicated for bonding of acrylic orthodontic appliances to
enamel.
Disadvantages of Unfilled Acrylic Resins :
Low hardness and strength
High co-efficient of thermal expansion
Lack of adhesion to tooth structure
High polymerization shrinkage.
E.g. of Unfilled Resins: Bracket Bond, Genie
www.indiandentalacademy.com
14. Epoxy Resins
The resins, which include a catalyst, are used in dental
composites, pit & fissure sealants and orthodontic bonding
resins. With so many different application, a large number of
dental products that use epoxy resins were developed,
especially Bis-GMA
Bis-GMA is an aromatic ester of a dimethacrylate,
synthesized from an epoxy resin (Ethylene glycol of Bis-
phenol A) and methyl methacrylate.
Disadvantages:
Lack of color stability
Water sorption
Patient sensitivity
Report by Athas and associates suggest that Endur M produced
carcinogenic effects. Endur M is now currently replaced with
Endur, which shows no carcinogenic effects on ingestion.
www.indiandentalacademy.com
15. Second Generation
These are UV light activated resins. The second-generation
materials provided greater bond strengths than had existed
previously. The major disadvantage were UV light itself. which
even with the best control was a moderate hazard and an indirect
technique with a tray carrier was needed to position the brackets.
This interfered with access of the UV light to the resin beneath
the brackets and made cleaning difficult.
It used Bowen's Hybrid molecule, similar to Epoxy resin, but
functional reactive groups are acrylic. It consists of
• Bisphenol glycidyl methacrylate
• Esters of alkyl benzoin were incorporated to facilitate UV
activation.
Advantages as compared to 1st
generation :
• Higher bond strengths when compared to first generation.
• Low polymerization shrinkage
• Greater hardness
• Low water absorption.
Disadvantages are radiation hazards and limited depth of curewww.indiandentalacademy.com
16. • Third Generation (Two paste system)
• Representative product Concise (3M)
• First to be tried by orthodontists in the early
days of bonding. Their application involves
mixing of the paste and liquid components.
• Compared with unfilled resins, the filled
resins have greatly improved thermal
expansion qualities.
• Silane was used to coat filler particles that
could bond chemically to the resin.
www.indiandentalacademy.com
17. The major constituents are
• Resin Matrix - Bis-GMA or
Urethane Dimethacrylate (UEDMA)/or
Triethylene glycol Dimethacrylate (TEGDMA).
• Filler Particles - are produced by grinding or milling quartz or
glasses to produce particles ranging in size from 0.1 to 100 /
microns. Silica particle (0.04 /lm) are obtained by pyrolytic
process. Depending on size of particle they are classified as:
Macro filled (10 to 30 microns) e.g. Concise.
Micro filled (0.2 to 0.3 microns) e.g. Endure, dynabond.
• Coupling agents: The bond between the two phases of
composite is provided by the coupling agent i.e., between resin
matrix and filler particles.
Titanates and Zirconates and organosilanes such as gamma
-methacryloxypropyltrimethoxy silane is most commonly
used.
www.indiandentalacademy.com
18. Activator-Initiator system
Third generation is two paste systems and activated by
autopolvmerization.
• One paste contains benzoyl peroxide initiator
• Other tertiary amine activator - (N, N-dimethyl-P-toluidine).
1- 2 % BP (benzoyl peroxide) in the monomer portion as a
free radical initiator.
The activator in the other paste for these materials has usual-
ly been a tertiary amine.
Most commonly di-hydroxyethyl-p-toluidine (DHEPT), which
gives better color stability than the traditional dimethyl-P-
toluidine (DMPT).
• The activator acts as an accelerator so that, on mixing, the
benzoyl peroxide fragments into free radicals at room
temperature, thus initiating polymerization.
Inhibitor
• To prevent spontaneous polymerization of monomers.
Inhibitor reacts with free radicals until they are depleted.
E.g. -7 butylated hydroxytoluene (0.01 wt %).www.indiandentalacademy.com
19. Disadvantages: Clinical handling
1. The manipulative process is problematic, relatively time-
consuming, and cumbersome.
2. Mixing of the two components introduces potentially critical
defects such as surface porosity and air voids in the bulk
material, owing to the prolonged exposure to air and the
inevitable entrapment of air bubbles.
3.High amount of monomer leaching.
Studies have shown that photo cured composites, intentionally
mixed as if they were chemically cured materials, also
demonstrated severely porous surfaces and voids in the bulk
materials.
Low degree of cure (DC-55%) and disproportionately high
amount of monomer leaching is attributed to the mixing
process and to the detrimental effect of air entrapment on the
carbon double- bond conversion in the vicinity of voids.
www.indiandentalacademy.com
20. 1 to 1 bonding system
It is one of the most popular and dependable 2-paste selfcure
adhesive systems available for direct or indirect bonding of
metal, Ceramaflex ceramic or plastic attachment.
Extra small quartz particles allow a smooth mix without
sticking to spatula.
Simple one to one mixing ratio of both the sealant resins and
bonding pastes make 1 to 1 easy to use. It eliminates bracket
drift and reduces decalcification due to the "feather edge" on
the tooth surface.
It is particularly recommended when close adaptation
between tooth surfaces and bonding pads is not possible as is
often the case with lingual bonding of brackets and retainers.
Working Time = 1 /2 minutes
It can be increased by cooling the paste and/or cooling the
slab.
www.indiandentalacademy.com
21. FOURTH GENERATION
No-mix adhesives
They were intended to minimize the mixing induced defects and
to reduce the steps
With these "no-mix" materials, the composite can be placed on the
tooth surface in unpolymerized form, while the polymerization
catalyst is placed on the back of the brackets. Contact between the
bracket and tooth with the intervening adhesive permits inter
diffusion of agents such as benzoyl peroxide (initiator) and amine
( activator) from the respective components.
Inhomogeneous polymerization pattern due to sandwich technique
involved in diffusion of liquid component into paste during
application. Enamel and bracket sides of adhesive are more
polymerized relative to middle zones
When the tray carrying the brackets is placed against the tooth
surface, the resin immediately beneath the bracket is activated and
polymerizes, but excess can be scaled away around the margins of
the brackets.
www.indiandentalacademy.com
22. Disadvantages
1. Artun and Zachrisson states that, some components of the fluid
reagents of no-mix systems, and of unreacted monomer have
recently been suspected of having a mutagenic potential.
2. The 'no-mix' adhesive according to them does not save time as
the archwire cannot be engaged with minimum of delay.
E.g.Monolok Unite.
'Right-on' No mix Adhesive
Right-on no mix adhesive is the most advanced self- cure
bonding system available. It provides superior bond strength
drift-proof bracket placement and 2-year shelf life without
refrigeration. The adhesive paste is conveniently preloaded in
syringes or disposable syringes to simplify bonding produces.
Archwires can be placed after 7 minutes after the last bond.’
Right-on' bonds metal, Ceramaflex ceramic or plastic brackets
to either etched enamel or acrylic crowns.
It may be used for indirect bonding
www.indiandentalacademy.com
23. FIFTH GENERATION
Compared with UV light, visible light has deeper curing capabilities, more
effective through enamel and does not diminish with time or with intensity
of the light source.
The light cured resin is a single paste system that consists of a ketone and
an amine as initiators. The ketone, camphoroquinone is sensitive to blue
light at 470 nm wavelength which catalyses the polymerization reaction.
VLC resin usually employs free radical initiators such as camphoroquinone
(CQ) and an amine reducing agent such as N, N-di-methyl-amino-ethyl
methacrylate (DMAEMA).
The radicalized ketone (CQ) alone may initiate the photo polymerization.
A reducing agent is generally added to light-cured composites for the
following reason. The amine radical is responsible for initiating the
polymerization and is more efficient than the radical formed from the
ketone. These intensified radicals can thus significantly improve the degree
of cure. The concentration of CQ photo sensitizer is in the range 0.17-1.03
mass% of the resin phase and that of DMAEMA reducing agent is 0.86
-1.39 mass%.
The combined photosensitizer/reducing agent complex has an extended
absorption band within the visible light (VL) spectrum.
www.indiandentalacademy.com
24. • Tavas and Watts showed that sufficient light may be
transilluminated by the teeth to effect adequate photo
polymerization of the material. In the case of translucent
ceramic brackets, light-curing is straightforward.
• Tawas and Watts developed the transillumination technique to
bond metal brackets onto teeth in vitro with visible light-cured
composite
• Results from laboratory investigations have suggested that
visible light-cured composite have similar physical properties
to chemically cured resins.
• Read stated that the entire adhesive under the bracket is
polymerized after initial exposure to visible light and that a
force can be immediately placed on the bracket after curing.
• The disadvantages of light-cured resin are associated with
incomplete polymerization beneath the surface and a limited
depth of cure. Doubling the exposure time and exposure
through tooth substance increased the cured depth.
www.indiandentalacademy.com
25. Reliance Quick Cure Orthodontic Paste
Light curing of a metal bracket in only 6 seconds with a conventional
curing light is possible. Unique chemistry provides a broader area of
sensitivity to blue light for a faster and more complete cure.
Ideal viscosity, no bracket floatation, easy cleaning, no stringing.
Quick cure paste can be used with light bond, assure or any light
cured sealant.
Transbond XT light cure adhesive
Transbond XT is currently distributed with instructions to cure both
the mesial and distal or incisal and gingival surfaces of metal
orthodontic brackets for 10 seconds each, for a total of 20 seconds
per bracket followed by immediate archwire insertion.
Advantages
Extended working time allows precise bracket placement.
Immediate bond strength, allowing archwire to be placed immediately
following cure.
It saves time for rebonds.
Efficient bonding of ceramic and metal brackets.
Excellent handling properties like -No bracket drift &easy flash clean
up.
www.indiandentalacademy.com
26. • The disadvantage of UV-light like 1 minute of curing per
millimeter of thickness led to development of visible Light cured
adhesives. The longer curing time (40 seconds) of these lead to the
introduction of Argon Lasers. They cure filled resins in 10
seconds and unfilled resins in 5 seconds, at a wavelength of 488
nanometer. More recently Xenon arc light units have been
introduced for rapid light curing.
• Visible Light cure emit light at 480 nm, but the energy is emitted
over a much broader range. Light from the Argon laser is
collimated, which results in more consistent power density over
distance. The power density of light Cure decreases dramatically
with distance due to divergence of light from the source. Visible
Light curing units uses bulbs, reflectors and filter which can
degrade and decrease curing efficiency.
• Nazir Lalani et al (Angle2000) found that 5 seconds was adequate
for bonding metal brackets. Increasing the time did not increase
bond strength significantly.
www.indiandentalacademy.com
27. Dual cure Resins
These resins are both light activated and chemically cured. Thus
they can be cured completely by using a light source or by the
catalyst and base reaction of the material. These resins originally
were applied to composite buildups and to cementing of laminate
veneers where depth of cure is essential.
Initiation is achieved through exposure to light. Reaction
proceeds following a chemically-cured pattern
Combines disadvantages of handling of both light-cured and
chemically cured materials. The most time consuming
applications
Increased degree of cure and bond strength, but questionable
clinical significance for their differences with light-cured
materials.
Introduced Into the profession from prosthetic dentistry
applications. Ideal candidates for bonding molar tubes.
www.indiandentalacademy.com
28. Smith and Shivapuja examined the dual cements
• Vivadent "thick"
• Vivadent "thin"
• Reliance "fluoride releasing".
"Thin" showed higher bond strength, because of reduced viscosity
and increased wetting. But handling properties are diminished
because of bracket drift. The "thick" cement has increased filler
particles, which reduced bracket drift.
The "fluoride releasing" has reduced bonding strength. It was
extremely viscous and all failures occurred at the tooth adhesive
interface.
Advantages of Dual cure resins
• Reduced curing time and good depth of cure.
• Its main advantage was reduced bonding time. In the visible LC,
time required to cure entire maxillary and mandibular arch is 13.5
minutes.
40 sec x 20 brackets = 13.5 minutes (VLC)
The curing time of Dual Cured resins is approximately 6.5
minutes.
10 sec x 20 brackets + 3 minutes for SC = 6.5 minutes (DC)
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29. Disadvantages
It centered on the chemically cured properties of the dual
cements.
1. Mixing may introduce bulk defects , increasing the porosity.
2. Placement of a bracket with half-hardened cement or
removing the flash from such a bracket would drastically
affect the bonding strength.
In orthodontic bonding, the clinician can control the setting
time by
1. Allowing the resin to set by chemical cure
2. Curing with visible light source for 30 seconds
3 Curing with a visible light source for 10 seconds and then
allowing the resin to completely polymerize with its
chemically cured properties. This gives more time for proper
placement of brackets. Furthermore, the clinician can be
assured of complete polymerization with the chemical
properties of Dual Cured cements.
www.indiandentalacademy.com
30. • Thermocured Introduced in orthodontics for indirect
bonding .
• It is claimed that these adhesives present increased
polymerization rates and hence superior properties.
• Not intended for direct bonding.
• Nanda & Sinha et al (1995 jco feb) They used a thermal
cured Fluoride releasing resin to secure brackets on the
model. For bonding on cast, they used Thermocure and
Maxicure sealant A & B was used in clinical setting.
• They reported a failure rate of 5 %
Drawback
• Bracket float
• Ceramic bracket cannot be exposed to heat
www.indiandentalacademy.com
31. REVIEW OF ARTICLES
A. Self cure
Advantages of Concise (two phase) over 'no-mix' Adhesive
(A.J. O. 1982 April)
According to Artun and Zachrisson
1. Bond strength of concise exceeds no mix adhesive.
2. More homogenous and predictable mix is obtained.
3. No reports of allergic reactions to Concise
4. Shorter "snap" time, it is possible to ligate archwires
sooner with Concise.
They recommended a four-handed approach to Bonding to
help mix the two paste system and enhance bonding
results.
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32. Whitlock et al (ajo1994) compared 3 different adhesive
systems, when used alone and with a porcelain-priming
agent, to bond ceramic brackets to porcelain surfaces. The
'no-mix' adhesive liquid had the lowest shear bond strength
without the priming agent and the highest bond strength with
the priming agent. This is because 'no-mix' adhesive liquid is
not polymerized before the bracket is applied.
Ching et al. (EJO2000) found that static loads such as tying in
of archwires can be placed on Brackets 15 minutes after
cementation, without a clinically significant reduction in
bond strength of a No-mix adhesive (Unite). Ireland and
Sheriff found that it was safe to tie to archwires on the same
visit, 1 hour after cementation of the No-mix adhesive (Right
on).
www.indiandentalacademy.com
33. B. VLC vs SC
• Greenlaw and Colleagues (1989 AJO ) found that the bond
strength of visible light cured adhesives was insufficient after
initial curing and suggested that the slow strength was due to
incomplete polymerization. They recommended delaying
archwire for 24 hrs. The Greenlaw study compared a visible
light cure adhesive (Heliosit Orthodontic) with a one-paste
chemically cured orthodontic adhesive (Unite). The Heliosit
was used for 20 seconds from incisal and 20 seconds from
gingival. The bond strength for the light-cured adhesive at one
hour was only 26% of that found at 30 hours, but was still only
one-half that of the chemically cured adhesive at 30 hrs.
• Larry and Colleague’s study indicate that there are advantages
to increasing the setting time of light cured adhesives.
Extending the setting time to 5 minutes produced more than
20% increase in bond strength, than 2 minutes. At the 2-
minute setting time, bonds cured for 40 seconds were 30%
stronger than those cured for 20 seconds.
He suggests therefore 40 seconds curing time, 20 on mesial
and 20 on distal for maximum shear strength.www.indiandentalacademy.com
34. • Wang and Meng (AJO l992) found that visible light is
powerful in curing the visible light-activated composite
resin under solid metal brackets. The bond strength of
light cured resin of Transbond, except in cases of light
exposure of 20 seconds, is stronger than that of the self-
cured resin of Concise. Transbond cured for 40 sec is
therefore recommended.
• Rashid Ahmed Chamda (AJO 1996) compared the bond
strength achieved with L.C. Bonding system and a
chemically cured system over a 24 hr period. There was
no significant difference between bond strengths
achieved by chemically cured & Light Cured systems at
10 minute, 60 minute and 24 hr interval.
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35. • Hugo R. Amass (Ajo98) compared L.C. achieve material
(sequence) and C.C. adhesive (System 1+) and found no
statistically significant failure rates between the two.
• Millet et al. (Angle98) found that failure rates of brackets
bonded with light cured resin (Transbond) to pre-molars were
almost twice that of brackets bonded to canines or incisors.
The large failure may be due to
1. Difficulty with moisture control.
2. Larger amounts of prismatic enamel.
• Hugo et al. (1998 AJO ) compared the failure rates of a
chemically cured resin (system 1+) and visible light cured
bonding material (sequence). There were no statistically
significant failure rates between the two.
www.indiandentalacademy.com
36. C. SC ( both two phase & no mix ) vs LC vs DC
Eliades et al., (EJO2000 AUG) compared the degree of cure
of
• A light cured (Transbond XL)
• Two pastes chemically cured (Concise)
• One phase (No-mix, chemically cure) – Unite
• Dual-cured (Two paste) - Duocement
Metal brackets and ceramic bracket were bonded.
1. The dual-cured product demonstrated the highest degree
of cure followed by
Light cured combined with ceramic bracket
No mix
Two paste chemically cured system.
• The combination of metallic bracket with the light cured
produced similar cure as that of the chemically cured
material.
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37. RECENT ADVANCES
The Prompt L-Pop System
• The Prompt L-Pop system is a unit-
dose system, with etchant, primer,
adhesive, and microbrush sealed in a
triple-lollipop-shape aluminum foil
package. Acid etching, rinsing,
priming and application of adhesive
are thus combined into one step.
Prompt L-Pop (ESPE Dental AG,
Seefeld, Germany) is an all-in-1
adhesive for composites and
compomers. Prompt L-Pop contains
methacrylated phosphoric acid esters
that combine an acidic component for
etching the enamel and the primer.
www.indiandentalacademy.com
38. Procedure
• 1. The enamel surface is pumiced or micro abraded.
• 2. The top bubble is folded, forcing the liquid into the
second chamber.
• 3. The second chamber is popped and folded forcing the
adhesive mixture into the third chamber, which contains
the microbrush. The brush is stirred around in the 3rd
chamber to saturate it with resin.
• 4. The adhesive is rubbed into the enamel surface for 15
seconds and air dried lightly to evaporate the water
carrier, leaving a smooth glossy surface rather than the
frosted appearance of phosphoric aid.
www.indiandentalacademy.com
39. • Prompt is a low ph - self-etching adhesive that procedures
a well defined etch pattern similar to that of phosphoric
acid.
• As with 4th and 5th generation adhesives, it forms a micro
retentive bond with the treated surface. Unlike these
systems, it allows the etchant and monomer to penetrate at
the same time, avoiding potential technique errors and
nanoleakage. Prompt shows outstanding bond strength to
both dentin and enamel.
• Light curing can be done with visible Light Curing unit or
more intense Argon lasers and Plasma-arc curing systems
by aiming at the adhesive bracket interface from the
occlusal surface.
www.indiandentalacademy.com
40. • Cyanoacrylate ( Moisture active adhesives )
• It requires rather than tolerate the presence of moisture for
proper polymerization. It does not require bonding agent. The
bonding surface must be intentionally wetted prior to
application. Bonding is just one step procedure. The presence of
saliva however adversely affects their long term clinical
performance
• A number of studies have found no adverse effects from long-
term use of cyanoacrylates inside the human body.
• Smart Bond (Gestenco) is not the same as the glue that can be
bought in a hardware store; its viscosity has been altered with
silica gel. It is also important that the surfaces to be bonded are
as close together as possible.
• Because polymerization starts only in the presence of moisture
and pressure, the clinical procedure for bonding with Smart
Bond differs from that of conventional adhesives.
www.indiandentalacademy.com
41. Disadvantage
1. Cyanoacrylate does not work well on polycarbonate brackets
with enlarged retention surfaces unless they are treated with
water.
2. The excess material will be instantly polymerized and turned
into white acrylic powder around the bracket, called "blooming".
3. The material cannot fill spaces or gaps, which is why a bracket
base with deep mesh or undercuts will have lower bond strength.
Advantages
1. Vapor from the unpolymerized material is immediately
polymerized when it comes in contact with water, which also
eliminates any taste.
2. No residual monomer can react later in the process, and thus
the material absorbs no water. This prevents the adhesive from
discoloring during treatment. High bond strengths are reported for
Smart Bond.
3. Smart Bond presents no particular danger of fracturing the
enamel during debonding.
www.indiandentalacademy.com
42. Fluoride-Releasing Orthodontic Adhesives
The presence of enamel demineralization or so-called
'white spots' is a significant problem. Incorporation of
fluoride into enamel structure as fluoroapatite can
result in remineralization of small decalcified or caries
lesions and also reduces the formation of new lesions.
Inorganic fluorides have high polar nature and dental
resins have low polarity, which causes loss of
mechanical integrity .
Organic fluoride incorporation has a plasticizing effect
that also yields poor properties.
www.indiandentalacademy.com
43. Rawls and Zimmerman (Ajo1989) introduced an experimental
fluoride releasing resin that has anti-cariogenic properties.
FR 2.5 Ortho adhesive is unique.
Fluoride release occurs when fluoride ions are exchanged for
other anions in the oral environment. Rather than supplying
fluoride to the oral environment by material dissolution, the
fluoride is given up in exchange for other anions and the
structure integrity of the resin is maintained.
• Underwood, Rawls and Zimmerman found that the use of this
adhesive resulted in 93% reduction of occurrence of dark
zones, indicating a reduction of early demineralization.
• Sansing, Rawls and Shage found that the bond strength of this
experimental resin compares favorably to existing commercial
adhesive.
www.indiandentalacademy.com
44. Adhesion Boosters or Adhesion Promoters
Adhesion booster, a tooth surface primer advocated by Bowen
et al., to increase the bond strength of composite resin to
tooth surface.
Two recently introduced boosters include
Enhance LC and All Bond 2
According to the manufacturer Enhance LC can increase
adhesion of composite to any enamel (including fluorosed,
hypocalcified, or deciduous enamel), metal or composite
surface.
With the adhesion Booster Megabond applied on the new
bracket base Newman et al., found that the bond strength
was lower than new brackets without Megabond, whereas
the bond strength of sandblasted new brackets with
Megabond was greater than brackets sandblasted without
megabond.
www.indiandentalacademy.com
45. Ching et al; compared Enhance LC and All Bond 2 to bond
debonded brackets.
They found that when new brackets are used neither All-
Bond 2, nor Enhance LC improves bond strength
significantly.
When rebonding debonded brackets, they found that without
the use of any boosters, sandblasted rebonded brackets yield
less bond strength than new brackets.
Enhance LC fails to increase bond strength of sandblasted
rebounded brackets.
All-Bond 2 significantly increased bond strength of
sandblasted rebonded brackets.
All-Bond 2 when used with sandblasted debonded brackets
provides comparable results (17 MPa) to new brackets.
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46. Hydrophilic Bonding Systems (Ajo200l)
Failure of orthodontic bonded attachments and
brackets is mostly due to contamination.
Materials that over come the moisture and
contaminants in the oral environment have been
developed. It contains hydrophilic primer
(HEMA) dissolved in acetone. HEMA is a water
soluble hydrophilic monomer .
Webster and Nanda compared 2 hydrophilic
bonding systems, MIP and Assure. Similar
bonding procedures were used; the difference
was in the application of primer.
www.indiandentalacademy.com
49. The results showed that the no contaminated surfaces had the
highest bond strengths for both the hydrophilic and
hydrophobic materials.
Transbond XT with primer -- 26.9 MPa
Transbond XT MIP -- 28.1 MPa
Assure with prime -- 20.4 MPa
When using hydrophobic primer, if the etched surface is
contaminated with saliva before primer application, it may
be necessary to reetch before proceeding with bonding.
If contamination occurs after primer placement and curing,
then a simple drying and reapplication of primer is all that is
necessary.
The hydrophilic primers also showed improved bond strengths
with reapplication of primer after saliva contamination.
www.indiandentalacademy.com
50. Adhesive Pre-coated Brackets
In an attempt to save chair side time during bonding,
orthodontists are using ceramic and metal brackets that have
been pre-coated with adhesive material.
The ingredients in the adhesive applied to bracket and that of
ordinary Transbond XT is the same. The difference is
limited to percentage of the different ingredients
incorporated.
Transbond XT contains
14% Bis GMA
9% Bis EMA
77% fillers (Silicate quartz and submicron silica).
The corresponding values for pre coated brackets is
12% Bis GMA
8% Bis EMA
80% fillers.
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51. • The composition changes are for increasing its viscosity,
causing the bracket to adhere more readily to the tooth during
initial stages of bracket positioning.
• Bishara et al compared the shear bond strength of ceramic and
metal brackets, which are not coated and pre-coated. They
found that
• 1. Pre-coated ceramic brackets have similar bond strength as
that of uncoated brackets bonded with adhesive.
• 2. Pre-coated metal brackets have lower bond strength than
uncoated brackets because of high viscosity causing less flow
into the mesh of the brackets.
• 3. All three provided clinically acceptable bond strength.
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53. REVIEW OF ARTICLE
SEP vs MULTI STEP CONVENTIONAL BONDING
1 (Bishara et al., AJO 2001). Brackets bonded with the SEP were
found to have a significantly lower mean shear bond strength
compared with those bonded with a conventional two-stage
adhesive system. The study, however, did not compare bonding
time for each adhesive system.
www.indiandentalacademy.com
54. •
Use of SEP to bond orthodontic brackets to the enamel surface resulted
in a significantly lower, but clinically acceptable, shear bond force as
compared with the control group
The comparison of the adhesive remnant index scores indicated that
there was significantly more residual adhesive remaining on the teeth
that were treated with the new self-etch primer than on those teeth that
were bonded with the use of the conventional adhesive system.
www.indiandentalacademy.com
55. Effect of self-etching primers on bond strength--are they
reliable? Angle 2003 Feb.
Karaman et al studied to determine the effects of using
three self-etching primers on the shear bond strength
(SBS) of orthodontic brackets and on the
bracket/adhesive failure mode.
• In the control group, teeth were etched with 37%
phosphoric acid. In the experimental groups, the enamel
was conditioned with three different self-etching primers,
Clearfil SE Bond (CSE), Etch & Prime 3.0 (EP3), or
Transbond Plus (TBP), as suggested by the manufacturer.
• The brackets were then bonded with Transbond XT in all
groups
www.indiandentalacademy.com
56. • TBP group produced significantly higher SBS ( 16.0 +/- 4.5
MPa) than that found in SE, EP3, and the control (acid-etched
[AE]) groups.
• CSE produced SBS ( 11.5 +/- 3.3 MPa) comparable to those
Acid etching ( 13.1 +/- 3.1 MPa).
• EP3 resulted in the lowest mean SBS value (mean 9.9 +/- 4.0
MPa).
• A comparison of the adhesive remnant index scores indicated
that there was more residual adhesive remaining on the teeth
that were treated with conventional acid etching than in the
CSE and EP3 groups. In the TBP group, the failure sites were
similar to those of the AE group but different from those of the
CSE group. www.indiandentalacademy.com
57. • Shear bond strength of orthodontic brackets bonded with a modified
1-step etchant-and-primer technique. Ajo 2003 oct Dorminey et al.
The purpose of this study was to compare the shear bond strength
of orthodontic brackets bonded to enamel with a conventional,
multistep adhesive system and a self-etching primer adhesive
system. In addition, a third group was included in which the air
dispersion step in the self-etching primer system was omitted.
SBS (SD) MPa
• group 1: conventional multistep adhesive 11.3 (2.2) MPa
• group 2: self-etching primer system 11.9 (3.2 MPa
• group 3: SEP system without air dispersion 8.2 (2.8) MPa
• The mean shear bond strength of the self-etching primer group in
which the air dispersion step was omitted was significantly less than
in the other 2 groups. There was no difference in mean shear bond
strength between the conventional, multistep adhesive system and
the self-etching primer system when the primer was dispersed
correctly www.indiandentalacademy.com
58. • SEP & SALIVA CONTAMINATION
• Efficacy of using self-etching primer with a 4-META/MMA-
TBB resin cement in bonding orthodontic brackets to human
enamel and effect of saliva contamination on shear bond
strength. Angle 2004 apr
Hayakawa et al
The objective of this study was (1) to evaluate the effectiveness
of Megabond when used with Superbond C&B, a 4- META/
MMA – TBB resin to bond orthodontic metal brackets to
human enamel and (2) to examine the influence of saliva
contamination on shear bond strength.
• 4- META/ MMA – TBB resin -----( 4-methacryloloxyethyl
trimellitate anhydride (4-META)/methyl methacrylate (MMA)-
tri-n-butyl borane (TBB) resin),
www.indiandentalacademy.com
59. There were no significant differences in shear bond strength
between phosphoric acid etching and self-etch priming for no
contamination, saliva contamination, and repeat treatment
(etching or priming) after saliva contamination.
• With phosphoric acid etching, saliva contamination
significantly decreased the shear bond strength.
• With self-etching primer treatment, however, saliva
contamination did not cause any decrease of bond strength.
• Phosphoric acid etching produced more enamel fracture than
self-etching primer treatment. Field-emission scanning
microscopy revealed less dissolution of enamel surface
resulted from self-etching primer compared with phosphoric
acid.
• These results suggest that Megabond when used with
Superbond C&B resin cement may be a good candidate for
bonding orthodontic brackets to human enamel.
www.indiandentalacademy.com
60. • SEP (INCLUDING F RELEASING )VS CONVENTIONAL
• Bishara et al ( Angle 2002 June
• In group 1 (control), teeth were etched with 37% phosphoric
acid; after the sealant was applied, the brackets were bonded
with Transbond XT and light cured for 20 seconds.
• In group 2, a self-etch acidic primer was applied as
suggested by the manufacturer, and the brackets were then
bonded with Transbond XT as in the first group.
• In group 3, an experimental self-etch primer EXL #547 was
applied to the teeth as suggested by the manufacturer, and
the brackets were then bonded as in groups 1 and 2.
• In group 4, a fluoride-releasing self-etch primer, One-Up
Bond F was applied as suggested by the manufacturer, and
the brackets were then bonded as in the other groups.
www.indiandentalacademy.com
61. One-Up Bond F (mean +/- SD strength, 5.1+/-2.5
MPa) and Prompt L-Pop (strength, 7.1+/-4.4 MPa)
had significantly lower shear bond strengths than
both the EXL #547 self-etch primer (strength, 9.7+/-
3.7 MPa) or the phosphoric acid etch and the
conventional adhesive system (strength, 10.4+/-2.8
MPa).
www.indiandentalacademy.com
62. Effect of water and saliva contamination on shear bond strength of
brackets bonded with conventional, hydrophilic, and self-etching
primers. Sfondrini et al AJO 2003 jun
• This study assessed the effect of water and saliva contamination on the
shear bond strength and bond failure site of 3 different orthodontic
primers
• Transbond XT,
• Transbond Moisture Insensitive Primer,
• Transbond Plus Self Etching Primer; used with a light-cured composite
resin (Transbond XT).
• Each primer-adhesive combination was tested under 7 different enamel
surface conditions: (1) dry,
• (2) water application before priming, (3) water application after priming,
(4) water application before and after priming,
• (5) saliva application before priming, (6) saliva application after priming,
and (7) saliva application before and after priming
www.indiandentalacademy.com
63. • SEP, MIP & CONVENTIONAL MULTISTEP
• Effect of water and saliva contamination on shear bond strength of brackets
bonded with conventional, hydrophilic, and self-etching primers.
• Sfondrini et al (AJO 2003 June) assessed the effect of of water and saliva
contamination on the shear bond strength and bond failure site of 3 different
orthodontic primers
• Transbond XT,
• Transbond Moisture Insensitive Primer,
• Transbond Plus Self Etching Primer; used with a light-cured composite resin
(Transbond XT).
• Each primer-adhesive combination was tested under 7 different enamel surface
conditions: (1) dry,
• (2) water application before priming, (3) water application after priming, (4)
water application before and after priming,
• (5) saliva application before priming, (6) saliva application after priming, and
(7) saliva application before and after priming
www.indiandentalacademy.com
64. • 1.Non contaminated enamel surfaces had the
highest bond strengths for conventional,
hydrophilic, and self-etching primers, which
produced the same strength values.
• 2.In most contaminated conditions, the self-etching
primer had higher strength values than either the
hydrophilic or conventional primers.
• 3.The self-etching primer was the least influenced
by water and saliva contamination, except when
moistening occurred after the recommended 3-
second air burst.
www.indiandentalacademy.com
65. Effect of saliva on shear bond strength of an orthodontic
adhesive used with moisture-insensitive and self-etching
primer
Chung et al. Ajo 2003 oct
Materials were :
• Transbond Moisture-Insensitive Primer (MIP)
• Transbond Plus Self-Etching Primer (SEP)
• Hydrophobic Transbond XT primer (XT) was used as a
control.
Conditions:
• (1) control: etch/dry/XT,
• (2) etch/dry/MIP, (3) etch/dry/MIP/wet (saliva)/MIP,
• (4) etch/wet/MIP, (5) etch/wet/MIP/wet/MIP,
• (6) dry/SEP, (7) dry/SEP/wet/SEP,
• (8) wet/SEP, and (9) wet/SEP/wet/SEP.
www.indiandentalacademy.com
66. • (1) Transbond XT adhesive with Transbond XT
primer and MIP in a dry field yields similar bond
strengths, which are greater than all other
groups,
• (2) saliva contamination significantly lowers the
bond strength of Transbond MIP,
• (3) saliva has no effect on the bond strength of
Transbond SEP,
• (4) Transbond XT adhesive with Transbond MIP
and SEP might have clinically acceptable bond
strengths in either dry or wet fields.
www.indiandentalacademy.com
67. Effect of blood contamination on shear bond strength of brackets
bonded with conventional and self-etching primers. AJO 2004 march
• Sfondrini et al assessed the effect of blood
contamination on the shear bond strength and bond
failure site of 2 different orthodontic primers
(Transbond XT and Transbond Plus Self-Etching
Primer) used with adhesive-precoated brackets.
• Four different enamel surface conditions were
tested: (1) dry, (2) blood contamination before
priming, (3) blood contamination after priming, and
(4) blood contamination before and after priming.
•
www.indiandentalacademy.com
68. • SEP & conventional in blood contamination
• Effect of blood contamination on shear bond strength of
brackets bonded with conventional and self-etching primers.
AJO 2004
• Sfondrini et al assessed the effect of blood contamination on
the shear bond strength and bond failure site of 2 different
orthodontic primers (Transbond XT and Transbond Plus Self-
Etching Primer) used with adhesive-precoated brackets.
• Four different enamel surface conditions were tested: (1) dry,
(2) blood contamination before priming, (3) blood
contamination after priming, and (4) blood contamination
before and after priming.
www.indiandentalacademy.com
69. • Noncontaminated enamel surfaces had the highest bond
strengths for both conventional and self-etching primers,
which produced almost the same strength values.
• Under blood-contaminated conditions, both primers
showed significantly reduced shear bond strengths.
• For the conventional primer, no significant differences
were reported among the blood-contaminated groups,
whereas when the self-etching primer was used, condition
4 reduced significantly the bond strength values
www.indiandentalacademy.com
70. • SEP: Transbond Plus & Ideal 1
• Comparison of the shear bond strength of 2 self-etch
primer/adhesive systems. Bishara & Laffoon. (AJO 2004) march
In group I, a self-etch acidic primer/adhesive system, Transbond
Plus (3M ), was applied on the enamel surface as suggested by the
manufacturer; it has 2 components that must be mixed before use.
The brackets were then bonded with Transbond XT and light-cured
for 20 seconds.
• In group II, a no-mix self-etch bracket adhesive system, Ideal 1
(GAC), was applied to the teeth. The self-etch primer has 1
component that does not need to be mixed before use. The brackets
were then bonded with the adhesive and light-cured for 20
seconds.
• The in vitro findings indicated that the shear bond strength
comparisons of the 2 adhesive systems were not significantly
different . The mean shear bond strength of the 2-component acid
etch primer was 5.9 +/- 2.7 MPa, and the mean for the 1-
component system was 6.6 +/- 3.2 MPa.
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71. SEP VS CONVENTIONAL & FUJI ORTHO LC
H21 Effect of using self-etching primer for bonding orthodontic
brackets. Angle 2002 dec
Yamada. et al determined the shear bond strengths of orthodontic
brackets bonded with one of four protocols:
• (1) a composite resin adhesive used with 40% phosphoric acid,
• (2) the same composite resin used with Megabond self-etching
primer,
• (3) a resin-modified glass ionomer cement adhesive used with
10% polyacrylic acid enamel conditioner, and
• (4) the same resin-modified glass ionomer cement used with
Megabond self-etching primer.
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73. • Megabond self-etching primer gave the same shear bond
strength as acid-etching when used with a resin-modified
glass ionomer cement.
• Megabond gave a significantly lower shear bond strength
when used with a composite resin adhesive.
• Megabond self-etching primer treatment produced less
enamel dissolution than did etching with phosphoric acid
and polyacrylic acids.
• The present findings provide evidence that Megabond self-
etching primer is a candidate for bonding orthodontic
brackets using the resin-modified glass ionomer cement,
with the advantage of minimizing the amount of enamel loss.
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74. • SEP - CONVENTIONAL & FLUORIDE
VARNISH
• F 3 Effect of fluoride varnish on the in vitro bond strength
of orthodontic brackets using a self-etching primer system.
Kimura et al AJO 2004
• The results showed no difference in bond strength among the
conventional or self-etching primer system.. Adhesive remnant
index scores were not statistically different. The application of
fluoride varnish does not affect the bond strength of orthodontic
brackets to enamel with conventional or self-etching primer
systems.
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75. CYANOACRYLATE & CONVENTIONAL
2001 Dec angle Bishara & Laffoon
•Cyanoacrylate did not show any significantly different shear bond
force (5.8 +/- 2.4 MPa) as compared to the control group (5.2 +/-
2.9 MPa).
•The comparison of the Adhesive Remnant Index scores indicated
that there was significantly less residual adhesive remaining on the
tooth with the cyanoacrylate than on the tooth with the conventional
adhesive system. In conclusion, the new adhesive has the potential
to be used to bond orthodontic brackets while reducing the total
bonding time.
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76. • Wilner and Oliver (Bjo2000sept) found that
cyanoacrylates are unsuitable for use as a
bonding agent in routine orthodontic
practice. The bond strength deteriorated
after few works. It can be used to adhere to
wet surface and where less force is required
for a short time, as in impacted canines
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77. • Effect of time on the shear bond strength of cyanoacrylate
and composite orthodontic adhesives. Ajo 2002 march
Bishara & Laffoon.
The bond strength of the cyanoacrylate adhesive was not
significantly different from that of the composite adhesive. Their
findings indicated that the cyanoacrylate and the composite
adhesives tested have clinically adequate shear bond strengths at
half an hour and at 24 hours after initial bonding. The clinician
needs to consider the properties of each adhesive: e.g., the need
to use a curing light and the ability to have more working time
with the composite adhesive versus no light but only a 5-second
working time before the cyanoacrylate adhesive starts to set.
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78. • HYDROPHILIC & HYDROPHOBIC PRIMER
• 1. Littlewood et al (BJO2000june) found that
the bonds strength obtained with the use of
hydrophilic primer (6.43 MPa) was significantly
lower than the conventional primer (8.71 MPa).
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79. Bond strength comparison of moisture-insensitive primers.
Foleyet al. AJO 2002 sept
The objective of this in vitro bonding study was to evaluate the
effectiveness of 2 moisture-insensitive primers, Assure and MIP
compared with a control hydrophobic primer, Transbond XT .
Protocols:
• (1) Transbond XT primer and adhesive applied to a non
contaminated surface;
• (2) Assure primer applied after saliva contamination;
• (3) MIP primer applied after saliva contamination;
• (4) Assure primer reapplied after saliva contamination;
• (5) MIP reapplied after saliva contamination; and
• (6) Assure adhesive applied after saliva contamination of the
primer.
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80. • 1. Both bonding systems provide adequate bond strengths whether saliva
contamination occurs before or after the application of the hydrophilic
primers; therefore, additional mechanical preparation and reetching of the enamel
surface after saliva contamination might not be required.
• 2. Comparing saliva contamination after application of primer(4 &5), both MIP and
Assure had significantly greater shear-peel bond strengths than when contamination
occurred before the application of each primer.
• 3. Transbond XT and MIP group 5 (contamination between 2 layers of primer)
showed significantly greater shear-peel bond strengths compared with the other
groups.
• 4. The groups with saliva contamination before application of the primer showed
more frequent failures at the enamel/adhesive interface, suggesting that complete
penetration of primer was prevented (nanoleakage) , whereas the groups with saliva
contamination after the first application of primer showed more frequent failures at
the adhesive/bracket interface.
• 5. The greatest frequencies for EF on debonding occurred in the groups with the
highest bond strengths.
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81. • angle 2003 aug
Klocke evaluated bond strength for a custom base
indirect bonding technique using a hydrophilic primer
on moisture-contaminated tooth surfaces.
• 1. Bond strength for the custom base indirect bonding
technique with the hydrophilic primer was not
significantly different in groups without contamination
and with water or saliva contamination before
application of the primer.
• 2. Moisture contamination after application of the
hydrophilic primer resulted in significantly lower bond
strength measurements compared with bond strength for
uncontaminated enamel.
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82. MIP UNDER MOIST & BLOOD CONTAMINATION
G19 The effect of moisture and blood contamination on bond
strength of a new orthodontic bonding material. AJO 2001 july
Hobson et al evaluated the bond strength of Transbond MIP
under dry, moist, and blood-contaminated conditions. Dry
bonding resulted in significantly higher bond strength (15.69
MPa) than moist (12.89 MPa) or blood-contaminated (11.16
MPa) bonds.
• However, all bond strengths were in excess of previous reports of
required clinical bond strength, and it was concluded that
Transbond MIP is a suitable adhesive for bonding in conditions
of poor moisture control or blood contamination
• Transbond MIP is therefore an ideal bonding agent for bonding
during the surgical exposure of teeth.
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84. • From the review of the above articles it can be
concluded that :
• 1.Non contaminated enamel surfaces had the
highest SBS for both the hydrophilic and
hydrophobic materials.
• 2.When the contamination occurred after the
primer was cured a simple drying and reapplication
of primer was enough to get adequate bond
strength.
• 3.Hydrophilic bonding systems showed improved
bond strength after reapplication of primer after
saliva contamination.
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85. • FLUORIDE RELEASING ADHESIVES
• .William A Wittshire and Sophia (AJO 95 SEPT) compared
two non-fluoride visible light-cured orthodontic adhesives
(Heliosit Orthodontic and Transbond) with 2 fluoride-
containing visible L.C orthodontic adhesives (FluorEver
OBA and Light Bond). The 2 non-fluoride adhesives, both
released small amounts of Fluoride, despite bring non-
fluoridated. The Fluoride release could be due to small
amounts of fluoride such as barium fluoride present in the
inorganic phase.
• Light-bond had an immediate burst of F release during the
1st day followed by sharp decrease such that F could not be
detected for 2 weeks longer than non-fluoride adhesives.
• FluorEver continued to release F up to 85 weeks.
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86. • Fluoride release from
FluorEver OBA up to
85 weeks.
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88. • .The study conducted by Oggard et al (Ajo 97Feb), with the
fluoride releasing adhesive orthodontic cement VP 862 found
that the anti cariogenic effect is due to release of fluoride in to
the local environment than elevation of fluoride level in
saliva. Orthodontic cement VP 862 is a halogen light curing
adhesive.
• Chung and Piatti (JCO2000 July) compared the clinical bond
strength of fluoride releasing phase II with non-fluoride
releasing Phase II. Phase II and the non-fluoride releasing
Phase II, both had failure rates of less than 2% at 3 months
and less than 5% at 6 months.
• They concluded that fluoride releasing Phase II is clinically
strong enough for use as an orthodontic bonding adhesive.
(Fluoride may leach out of the material by ion exchange with
other anions in the oral environment, as proposed by Rawls
and Zimmerman.According to them, this type of fluoride-
exchanging resin should maintain its physical properties,
since the fluoride is given up in exchange for other anions.)
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89. • RESIN MODIFIED GIC , HYBRID GIC &
CONVENTIONAL COMPOSITE
• Foley & Mamandras (AJO 2001 Jan) The objective
of this study was to compare 3 orthodontic adhesives in
the areas of shear-peel bond strength, location of
adhesive failure, and extent of enamel cracking before
bonding and after debonding of orthodontic brackets.
• The adhesives included a composite resin control
(Transbond XT)
• A resin-modified glass ionomer cement (Fuji Ortho
LC)
• A polyacid-modified composite resin( GIC HYBRID)
under dry and saliva-contaminated conditions (Assure).
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90. 1.Transbond XT displayed significantly greater shear peel bond strength than Fuji
Ortho LC and Assure, although the bond strengths for all 3 adhesives were clinically
acceptable.
2. There was no significant difference in mean shear-peel bond strengths between
Assure-wet (saliva-contaminated) and Assure-dry (non-contaminated) protocols.
3. Fuji Ortho LC and Assure-wet tended to display adhesive failure at the
enamel/adhesive interface while Assure-dry and Transbond XT tended to display
cohesive failure within the adhesive.
4. The greatest frequencies for enamel fracture upon debonding occurred in the groups
showing the highest bond strengths (Transbond XT and Fuji
Ortho LC). www.indiandentalacademy.com
91. • Adhesives that Bond Chemically to Metal
• During the 1980's, primers such as Fusion and
adhesives such as Enamelite 500 and Goldlink
were introduced for bonding to gold and dental
metal alloys, they were not very effective.
• Attachments are then bonded with highly filled
adhesives (e.g. Concise) to the metal.
• 2 different types of adhesives, 4-META resins
and 10-MDP Bis- GMA resins have recently
been developed to improve adhesion to metals.
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92. Intermediate Resins to Enhance Bond Strengths
All-Bond 2 and Scotch bond MP (Multipurpose) are the most
popular and complete intermediate resins available today.
All-Bond 2
A third generation dentin-bonding agent contains a 10%
phosphoric acid gel for dentin conditioning. One drops
each of Primer A and Primer B are mixed and applied to
the enamel until the acetone solution evaporates. The site is
then air dried for 5 to 10 seconds. All-Bond 2 can be used
to increase the strength of any adhesive by this method.
Primer B is claimed to be an effective metal primer when
repairing a porcelain-metal crown or bonding a metal-based
restoration.
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93. • Bonding to Amalgam
• Amalgabond (Super-Bond D Liner) is a 4-META
resin that bonds to amalgam, as do Super Bond C
& B. This cures in 60 seconds.
• All Bond 2 and Amalgabond can be used during
initial placement. Scothbond MP - Should be used
only on hardened, Sandblasted amalgam .
• Another 4-META intermediate resin that will
enhance bond strength to artificial tooth surfaces
and has a short polymerization time (30 seconds) is
Reliance Metal Primer.
• Therefore Amalgabond plus or Reliance Metal
Primer can be used as an intermediate application
before bonding with composite resin to amalgam
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94. • Bonding to glazed porcelain with the assistance of a
coupling agent (Silane) as an interface between the porcelain
and the bonding agent. Silanes are recognized as coupling
agents for bonding glass fillers intc polymers. Studies have
shown that silane coupling agent will increase the adhesion of
resins to dental porcelain.
• Silane also helps in bonding brackets to composite prosthetic
restorative material (Isosit), a heat cured composite resin.
• The silane solution is prepared according to the protocol
presented in the work of Chen and Brauer. It contains.
• 5% Vol of silane (gamma - methacryloxypropyl
methoxysilane)
• 2% wt% of n-propylamine, in acetone
• eg : Ormco Porcelain primer, Scotch prime ,Clearfill
porcelain bond
• The bond strength produced by this method is apparently
inadequate for orthodontic purposes.
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95. • High-Q-Bond (HQB)
• HQB is a dentin-bonding agent that belongs to the
fourth generation of dental adhesives.
• It is composed of acrylic monomers
methylmethacrylate (MMA) crosslinked with a
multifunctional agent, an adhesion promoter a co-
monomer-aliphatic polyester and initiators for
selfcuring process (dimethyl-P-toluidine and Benzoyl
peroxide). It also includes poly MMA, inorganic
fillers and coupling agent.
• HQB provides high tensile bond strength and can be
used for bonding to various substrates such as
enamel, noble and base metal alloys, amalgam,
composite and porcelain.
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96. • Degradation of Polymeric Systems
Degradation of high polymers can be character-ized into two
broad areas:
Random,
Where chain rupture is induced by one or more factors" such
as exposure to ozone, oxygen. ultraviolet radiation, and
foreign agents. This type of degradation occurs at random
sites in the polymer structure, resulting in the release of large
structural fragments.
Chain depolymerization, where release of monomer occurs
in a more organized man-ner (depropagation).
Depropagation is virtually the reverse of polymerization
where bond breakage is initiated at a chain defect site and a
hydrogen atom is released from the polymer structure. The
polymer chain then splits, and both a free radical and an
inactive species are created.
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97. Carbon double bond unsaturation (C = C )
Water sorption
Composite resin solubility
Micro cracks
Diffusion channels
Degradation process.
Bacteria
& enzymes
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98. • Munksgaard and Freud demonstrated the occurrence of
enzyme-induced degradation of di-methacrylate polymers
and the hydrolytic nature of the process.
• Their work was preceded by experiments in several polymer
systems that consistently showed enzymatic activity-
induced degradation of the materials.
• Initially, the applicability of these laboratory results to the
clinical situation was questioned: Investigators claimed that,
under clinical conditions; the' composite resin is covered by
a proteinaceous film (pellicle) that masks the surface layer
presumably decreasing its reactivity with the environment
and any subsequent attraction and adsorption of molecular'
complexes. Such adsorbed substances might affect' the
'enzymatic activity of adjoining resin molecules in an
unpredictable manner.
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99. • However, Matasa has demonstrated that
aerobic and anaerobic microbial activity
'may weaken the resin, leading to
compromised bond strength. These effects
were attributed to the ability of some
microbes to metabolize adhesive
constituents. A suggestion was made to
incorporate substances in the adhesive with
bactericidal activity similar to the approach
of including gentamycin in bone cements
(PMMA-based) intended for use in total hip
replacement arthroplasties.
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100. • Leaching of Orthodontic Adhesives
• Water immersion has been reported to cause release of 50% of
the leachable species while ethanol-water immersion accelerated
the release rate to 75 % from dental resins during the first three
hours.
• Ferracane and Gordon were unable to detect further elution from
composite resins after 24 hours of immersion.
• In contrast, other investigators found prolonged elution from
composite resins and orthodontic adhesives Which continued for
115 days and two years, respectively.
• Ethanol-water baths tend to accelerate the degradation of
composite resins when compared, to water immersion, and also
promote elution of leachable species.
• The quan-tity and composition of the eluted substances are key
factors for the toxic potential of a resin adhesive. In general the
maximum accepted weight loss of restorative material has been
stipulated at 5microgram /mm3. Filler components (mainly
silicon) have been estimated to account for approxi-mately 180
micro mol/g weight loss.
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101. • Eluted substances include fillers, enzymatic
hydrolysis-induced methacrylic acid, benzoic acid
resulting from degradation of the benzoyl
peroxide initiator, and materials probably
originating from the polymerization accelerators
and catalysts.
• A serious concern arises from the formation of
formaldehyde (H2C= 0) as an oxidation reaction
product of oxygen with the carbon-carbon double
bonds , Oxygen is capable of detaching the
pendant group from the polymer network, leading
to structural degradation.
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102. • AJO1995 Sep Eliades and Brantley in their study of residual
monomer leaching from three adhesives showed that
• 1. No statistically significant differences in the amount of
released monomers were found among the ceramic bracket
groups bonded to the visible light-cured adhesive and photo
polymerized under direct or indirect irradiation.
• 2. The polycarbonate base ceramic bracket demonstrated
significantly higher amount of released monomers compared
with ceramic brackets. Evidence of degradation of the
polycarbonate base was detected.
• 3. The highest amount of residual monomers was eluted from
the chemically cured adhesive group. The visible light-cured
adhesive bonded to the stainless steel brackets under indirect
irradiation showed values comparable to ceramic brackets,
while direct irradiation resulted in high amount of eluted
monomers.
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103. • CYTOTOXICITY
• – Davidson et al ( 1983 AJO)
• Orthodontic bonding materials were tested for in vitro cytotoxicity
by an agar-diffusion cell culture technique. Vero cells were grown
in a monolayer, covered with an agar/medium overlay, and exposed
to equal amounts of orthodontic adhesives immediately after
polymerization and at various time periods up to 30 days after
mixing. The diameter of the area of unstained, nonviable cells (zone
of inhibition) provided a quantitative measure of toxicity.
• All materials were found to show cytotoxicity immediately after
preparation, with the activator components of two "no-mix"
materials exhibiting significantly higher toxicity than other
materials tested. Polymerized adhesives generally showed decreased
toxicity following soaking in saline solutions which simulated the
bathing of materials by intraoral fluids. The sealant materials
showed statistically significant greater toxicity than paste resins,
both initially after mixing and after 30 days.
• The significant finding in this study was that these materials not
only were toxic immediately after mixing but remained toxic for
extended periods of time. Excess material should be removed from
teeth by thorough scaling and flushing with water and high-speed
evacuation, particularly in areas adjacent to the gingiva.
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104. 1. Cytotoxicity of direct-bonding adhesives –
Davidson (AJO 1988 May )in their study
showed that different direct bonding adhesives
were toxic to varying degrees in vitro and that
toxicity decreased more rapidly for some
adhesives than others. Although these results do
not necessarily translate to any direct toxic
effects on patients, they do indicate that this
technique can detect a potential long-term toxic
effect in orthodontic adhesives, which should
warrant further prudent in vivo animal model
testing.
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105. Thank you
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