Introduction
CERAMICS : An inorganic compound with non-metallic prosthesis typically consisting of oxygen and one or more metallic or semi-metallic elements that is formulated to produce the whole part of a ceramic based dental prosthesis. – GPT 7.
The word Ceramic is derived from the Greek word “keramos”, which literally means ‘burnt stuff’, but which has come to mean more specifically a material produced by burning or firing.
Introduction
CERAMICS : An inorganic compound with non-metallic prosthesis typically consisting of oxygen and one or more metallic or semi-metallic elements that is formulated to produce the whole part of a ceramic based dental prosthesis. – GPT 7.
The word Ceramic is derived from the Greek word “keramos”, which literally means ‘burnt stuff’, but which has come to mean more specifically a material produced by burning or firing.
All details about the dental cements
Introduction
Definitions
Ideal properties
Classification
Based on Ingredients & Application(craig)
Based on Bonding mechanism(william O’Brien)
Based on setting reaction (Anusavice)
Silicate cement
Zinc phosphate cement
All details about the dental cements
Introduction
Definitions
Ideal properties
Classification
Based on Ingredients & Application(craig)
Based on Bonding mechanism(william O’Brien)
Based on setting reaction (Anusavice)
Silicate cement
Zinc phosphate cement
Cements in orthodontics (2) /certified fixed orthodontic courses by Indian de...Indian dental academy
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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
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A Modified Partial Platform Technique to Retrieve Instrument Fragments from C...Nadeem Aashiq
A Modified Partial Platform Technique to Retrieve Instrument Fragments from Curved and Narrow Canals: A Report of 2 Cases
Narasimhan B, Vinothkumar TS, Praveen R, Setzer FC, Nagendrababu V. A (J Endod 2021;47:1657–1663
Stress distribution within the ceramic veneer-tooth system with butt joint an...Nadeem Aashiq
Chai SY, Bennani V, Aarts JM, Lyons K, Das R. Stress distribution within the ceramic veneer-tooth system with butt joint and feathered edge incisal preparation designs. J Esthet Restor Dent. 2021 ;33(3):496-502
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
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
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
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Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
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TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
3. INTRODUCTION
Cement is defined as a substance that hardens to act as a base,
liner, filling material, or adhesive to bind devices and prostheses
to tooth structure or to each other.
- Phillips’ science of dental materials 11th edition
Dental cements are generally inorganic, nonmetallic substances
that harden to act as a base, liner, or restoration or as an
adhesive to bind devices or prosthesis to tooth structure.
Dental cements are commonly powder-liquid systems that set via
acid-base reaction or chelation. They are used for restorative,
endodontic, orthodontic, periodontic as well as surgical
procedures.
Last 2 decades have seen a variety of changes in the dental
cement composition and also introduction of newer advanced
biocompatible materials.
3
8. BASED ON TYPE
TYPE I : LUTING AGENT includes Temporary cements
- Powder-Liquid --- hardens
- Paste-Paste --- remains soft
TYPE II : LUTING AGENT for permanent restoration
TYPE III : TEMPORARY LINER OR BASE APPLICATION
TYPE IV : PERMANENT LINER OR BASE APPLICATION
9. IDEAL REQUIREMENTS
Non-toxic, Non-irritant to pulp and tissues
Insoluble
Adhesion to enamel and dentin
Bacteriostatic
Obtundant effect on pulp
Thermal, chemical and electrical insulation
Optical properties
9
10. ZINC PHOSPHATE CEMENT
Introduced by Dr. Otto Hoffman during the
1800s
One of the oldest cement
Acts as the gold standard by which newer
materials are compared.
APPLICATION
Luting of restorations
Luting of orthodontic bands
High strength bases
10
12. TYPES
Type I –
Fine Grained : (Film Thickness less than 25µm)
Luting permanent metallic restorations
Cementation of orthodontic bands
Type II –
Medium Grained : (Film Thickness of 40µm)
High strength thermal insulating base
12
13. SETTING REACTION
Phosphoric acid attacks the surface of the particles
Releases zinc ions into the liquid
Aluminium forms complexes with phosphoric acid, reacts with zinc
forming zinc aluminophosphate gel.
Exothermic reaction.
The final set cement is a cored structure consisting primarily of
unreacted zinc oxide particles embedded in a cohesive amorphous
matrix of zinc aluminophosphate
3ZnO+2H3PO4 +H2O Zn3(PO4)2.4H20
(zinc phosphate)
13
14. Frozen Glass slab Technique:
To prolong working time and shorten setting time.
Glass slab cooled at 6°C or – 10°C.
50 – 75% more powder incorporation.
Working time is increased by 4 – 11 mins
Setting time shortened by 20 – 40%
14
15. FACTORS AFFECTING SETTING
TIME
Reducing the P:L ratio increases the working time and setting
time
Low initial pH which will impair the mechanical properties
Smaller increments mixed for first few increments
Prolonging the spatulation time
Temperature of the mixing slab
15
16. BIOLOGIC PROPERTIES
Freshly mixed ZnPO4 - highly acidic pH - pulpal irritation
Very thin mixes must be avoided as it can be highly acidic.
Pulp protection -
High P:L ration must be used, Calcium hydroxide or cavity
varnish
ADHESION :
By mechanical interlocking of the set cement with cavity
surface roughness
Acts as a good thermal insulator.
16
17. MODIFIED ZINC PHOSPHATE
CEMENT
COPPER & SILVER CEMENTS
Black copper cements : Cupric oxide
Red copper cements : Cuprous oxide
Depending on the type of copper cement, concentration of
the copper varies between 2% and 97%.
Lower P:L ratio – for satisfactory manipulation
characteristics
Highly acidic
Higher solubility
Lower strength than ZnPO4
Less anticariogenic property
Silver cements : contain small percentage of salts of silver
phosphate
17
18. FLUORIDE CEMENTS
• Stannous fluoride (1-3%)
• Higher solubility and lower strength – due to
dissolution of Fluoride
• Fluoride uptake by enamel : Reduced enamel
solubility and Anticariogenic
MODIFIED ZINC PHOSPHATE
CEMENT
18
19. SILICATE CEMENT
Fletcher in 1871
Oldest direct tooth colored materials
Steenbock later introduced an improved version
of the cement
The use of dental cement as a restorative
material began with silicate cement.
Silicates are rarely used nowadays. This is due
to development of better materials like composite
resin and glass ionomer cement
Commercial Names-
Biotrey
Silicap
19
21. Properties
Compressive stength -180MPa
Tensile strength – 3.5 Mpa
Silicates are translucent and resemble porcelain in
appearance
Severe irritant to pulp
dissolve and disintegrate in oral fluids
Anticariogenic properties- contain fluoride up to 15%
21
22. Clinical Significance
The incidence of secondary caries is markedly less around
the silicate cement restoration.
fluoride provides a source of fluoride uptake to the adjoining
tooth structure during insertion and hardening of the cement.
This results in a substantial reduction in enamel acid
solubility much as in a topical application of fluoride solution
It exhibit good esthetic qualities for a short time after
insertion.
22
23. Disadvantages
Severe pulp irritation due to low Ph (5 -3.2)
It lacks stability in oral fluids , disintigration
loss of esthetic qualities due to discoloration
Shrinkage on setting
Rubber dam is essential for successful silicate restoration.
Are not being used recently
23
24. SILICOPHOSPHATE CEMENTS (ADA
Sp. No.96)
Presence of silicate glass: translucency, improved strength,
fluoride release.
APPLICATIONS
Type I : Cementation of fixed restorations
Type II : Provisional restorative material
Type III : Dual purpose material
24
28. ZINC POLYCARBOXYLATE
CEMENT
• Dennis Smith : 1968
• First cement system with adhesive bond to
tooth structure
• Also known as polyacrylate cement
APPLICATION
• Luting alloy restorations
• Thermal insulating bases
• Cementing orthodontic bands
• Cementing SS crown in pediatric
dentistry
Commercial names-
• Poly F (Dentsply)
• Durelon
• Carboco (voco)
28
30. Methods to Increase the working
time
Cooling glass slab :
Thickening of the liquid
Powder refrigerated before mixing
Reaction occurs on cool surface, cool temperature retards the
reaction without thickening of the liquid.
30
31. SETTING REACTION
particle surface dissolution by the acid
release of zinc, Mg and Sn ions
Ions bind to the polymer chain via the carboxyl groups.
These ions react with carboxyl of adjacent polyacid chains
cross linked salt is formed as the cement sets.
The hardened cement consists of an amorphous gel matrix
in which unreacted particles are disposed
31
32. PROPERTIES
• Solubility in water is low
• In organic acid with pH < 4.5 : increased solubility
• Reduced P:L ratio : increases solubility in oral cavity
32
33. BIOLOGIC EFFECTS-
Good biocompatibility
Low intrinsic toxicity
Rapid rise in pH towards neutrality
Fluoride release
33
34. ZINC OXIDE EUGENOL (ADA SP.
NO. 30)
• Introduced by Chrisholm in 1873
• Commonly used for luting and intermediate
restorations
• Obtundant property on exposed dentin
APPLICATION
• Longterm and short-term luting agents
• Temporary and intermediate restorations
• Root canal sealers
• Surgical packs
34
35. TYPES (ADA Specification No. 30)
Type I : Temporary restorations
Type II : Permanent cementation of restorations
Type III : Temporary restoration, thermal insulating bases
Type IV : Cavity Liner
35
37. SETTING REACTION
Hydrolysis of the ZnO
ZnO + H2O Zn(OH)2
Zn(OH)2 + 2HE ZnE2 + 2H20
Zinc hydroxide reacts with acid eugenol forming zinc eugenolate which
crystalizes and strengthens the cement
Set cement also contains free zinc oxide embedded in a matrix of zinc
eugenolate
Reaction is reversible, zinc eugenolate can easily be hydrolysed by
moisture in the oral cavity to eugenol and zinc hydroxide
37
42. SETTING REACTION
Similar to ZnO eugenol
Acidic resin such as colophony may react with zinc oxide,
strengthening the matrix
MANIPULATION
(Method similar to ZnO eugenol)
More powder is required for cementing mix
Proper P:L ratio must be followed for adequate strength
properties
Mixing pad/slab should be completely dry
42
43. PROPERTIES
Solubility is lower than ZnO eugenol cement due to the presence of resin
BIOLOGIC EFFECTS
• Inflammatory reaction in the connective tissue is present
• Softening and discoloration of the resin material
43
45. EBA MODIFIED ZINC OXIDE
EUGENOL CEMENT
APPLICATION
Cementation of inlays, crowns, FPD’s and for provisional restoration
Base / lining material
COMPOSITION
45
46. SETTING REACTION
Not fully known
Appears to form chelate salt between EBA, eugenol and zinc oxide.
MANIPULATION
Similar to ZnO eugenol
Cement mixes readily to very fluid consistency even at a high P:L
ratio
For optimal properties : use high P:L ratio as possible
3.5 g/ml : cementation
5 – 6 g/ml : liners and bases
Vigorous spatulation is required for about 2 mins to incorporate all of
the powder
46
48. NONEUGENOL CEMENTS
EBA- ethoxy benzoic acid
Advantages over ZOE:
No irritation to soft tissue
Compatible with acrylic resin materials
48
49. ADVANTAGES
Easy manipulation
Long working time
Good flow characteristics
Good strength characteristics
Minimal irritation to the pulp
Best suited to cutting of
restorations with good fit retention
Where there is no under stress
and for cavity bases.
DISADVANTAGES
More critical proportioning
Hydrolytic breakdown in oral
fluids
Liability to plastic deformation
Less retention than zinc
phosphate cements
49
50. GLASS IONOMER CEMENT
Synonyms
Poly (alkenoate) cement
GIC (glass ionomer cement)
ASPA (alumino silicate polyacrylic acid)
Manmade dentin
These cements have the combined properties of silicate cements and
polycarboxylate cements.
50
51. CLASSIFICATION
Type I - Luting
Type II - Restoration
Type III - Liner and bases
Type IV - Pit & Fissure sealants
Type V - Orthodontic cement
Type VI - Core build up
Type VII - high fluoride releasing
Type VIII - ART
Type IX - geriatric and pediatric uses
51
53. LIQUID
Polyacrylic acid – 40-50%
Tartaric acid – improves the handling characteristics
increases working time
In most current cements -Acid is in the form of a copolymer
with-
• Itaconic acid
• Malic acid
• Tricarboxylic acid
53
54. CHEMISTRY OF SETTING
powder and liquid are mixed to form a paste,
the acid etches the surface of the glass particles and calcium, aluminum,
sodium, and fluoride ions are leached into the aqueous medium.
The polyacrylic acid chains are cross-linked by the calcium ions that are
replaced by aluminium ions within the next 24 hours.
Sodium and fluorine ions do not participate in cross- linking of the
cement.
Some of sodium ions may replace the hydrogen ions of carboxylic group,
whereas the remaining ions are dispersed uniformly within the set
cement along with fluorine ions.
54
55. MODIFICATIONS
Metal reinforced glass Ionomer cement
Glass ionomer cements can be reinforced by physically
incorporating silver alloy powder (spherical amalgam alloy)
with glass powder (type II glass ionomer cement), usually
referred as SILVER ALLOY ADMIX / MIRACLE MIX.
It can be also reinforced by fusing glass powder to silver
particles through sintering, which is referred as CERMET.
55
56. RESIN MODIFIED GLASS IONOMER
CEMENT
(HYBRID IONOMER or Dual-Cured GIC)
COMPOSITION
POWDER
Contains radio opaque, ion-leachable fluoroaluminatesilicate glass
particles and micro encapsulated catalyst system and initiators for light
curing and chemical curing
LIQUID
Contain water and polyacrylic acid
Polyacrylic acid modified with methacrylate and hydroxyethyl
methacrylate (HEMA) monomers
Methacrylate and hydroxyethyl methacrylate (HEMA) are responsible
for polymerization
56
57. SETTING REACTION
The initial setting reaction :
polymerization of methacrylate group
The slow acid-base reaction will ultimately be responsible for
the unique maturing process and the final strength.
The overall water content is less for this type of material to
accommodate the polymerizable ingredients
57
58. PROPERTIES
The fluoride release is at the same level as conventional
glass ionomr cement.
Tensile strengths are higher than conventional glass ionomr
cement.
Increase in tensile strength is mainly attributable to their
Lower elastic modulus
The greater amount of plastic deformation that can be
sustained before fracture occurs.
The mechanism for bonding to tooth structure is the same as
that for conventional glass ionomr cement
58
59. Less ionic activity is expected because of the reduction in
carboxylic acid in the liquid of resin-modified glass ionomers.
Bond strength to tooth structure can be higher than that of
conventional glass ionomer cements.
Exhibit a higher bond strength to resin based composites.
Lower water and carboxylic acid content also reduce the
ability of the cement to wet the tooth substrates which can
greatly increase microleakage compared with conventional
glass ionomer cements.
The biocompatibility of hybrid glass ionomers is comparable
to that of conventional glass ionomer cements.
59
60. INDICATIONS
Liners
Fissure sealants
Bases
Permanent cementation of crowns and bridges to tooth structure
Core build ups
Cementation of posts
Bonding of orthodontic appliances
60
61. Restoration of class I, III or V .
Repair materials for damaged amalgam cores or cusps.
Retrograde root filling material.
Most products are not recommended for cementations of all
ceramic inlays, onlays / crowns because of their water
sorption, which leads to expansion, which can cause
cracking of the ceramic restoration.
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62. RESIN CEMENTS
COMPOSITION AND CHEMISTRY
The basic COMPOSITION of most modern resin cements is
similar to that of composite resin filling materials, but generally
have lower concentrations of filler particles.
The filled resin cements consist of a resin matrix with inorganic
fillers that are bonded to the matrix via coating with organo
silane coupling agent.
The resin matrices generally are diacrylate monomers diluted
with low- viscosity dimethacrylate monomers.
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63. Some of them incorporate the bonding mechanism utilized by
dentin bonding agents in the form of organophosphates,
HEMA (hydroxymethyl methacrylate) and the 4 META (4
methacrylate trimellitic anhydride) system.
Bonding of the cement to enamel can be attained by the
acid- etch technique.
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64. PROPERTIES
Setting time – 2-4 minute
Film thickness - < 25 micro meter
Compressive strength- 70-172 MPa
Solubility & disintegration in water – 0.00-0.01% weight
Pulp response – Moderate
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65. CHEMISTRY OF REACTION
Polymerization is achieved by the conventional peroxide-amine
system or light activation.
A few systems utilize both mechanisms and are referred to as
“dual cure” materials.
Light cured cements are normally used for cementation of
restorations or appliances that transmit light.
Fillers –Silica or glass particles( 10-15 micro meter diameter)
-Colloidal silica
The filler levels vary from about 30% up to around 80% by weight.
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66. With Respect to bonding to dentin, the adhesive cements
that incorporate the organophosphates, HEMA (hydroxiethyle
methacrylate) or 4 META (4 methacrylethyle trimellitic
anhydride) adhesion systems generally develop reasonably
good bond strengths to dentin.
Some of the other commercial resin cements furnish a bond
agent as a separate component of the cement system.
It should be emphasized that bonding may be more critical
for resin cements than for some other types of cement
because they possess no anticariogenicity.
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67. BIOLOGICAL PROPERTIES
Resin cements just like the composite restorative resins are
irritating to the pulp.
Thus pulp protection via a calcium hydroxide base is
important when one is cementing an indirect restoration in a
cavity that involves dentin.
If the bonding area involves only enamel, the irritating
properties of the monomers are not of consequence.
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68. LIGHT CURED CEMENTS are single component systems
just as are the light-cured filling resins.
They are widely used for cementation of porcelain and
castable glass restorations and for direct bonding of ceramic
orthodontic brackets.
The time of exposure to the light that is needed for
polymerization of the resin cement depends upon the light
transmitted through the ceramic restoration or bracket and
the layer of polymeric cement.
The time of exposure to the light should never be less than
40 seconds.
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69. The DUAL-CURE CEMENTS are two-component systems
and require mixing just as for the chemically activated
systems.
The chemical activation is very slow, which provides
extended working time until the cement is exposed to the
curing light, at which point cement solidifies rapidly.
It then continues to gain strength over an extended time
period owing to the chemically activated polymerization.
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70. APPLICATIONS
Used to attach either resin or ceramic veneers to the surface
of anterior teeth using the acid etch technique.
It is a choice in cementation of resin bonded bridges.
These are widely employed for intermediate prosthesis.
It is also involves in direct attachment of orthodontic brackets.
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71. CALCIUM HYDROXIDE
Hermann – 1920
Useful water setting cement which has osteoconductive
and osteoinductive property
As a pulp capping agent facilitates formation of reparative
dentin– alkaline pH, antibacterial and protein lyzing
property.
TYPES:
Non setting (pH : 11 – 13) – intracanal medicament
Setting (pH : 9 – 10) – cavity liner
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72. APPLICATION
Liners in deep cavity preparations
Intracanal medicaments
Direct and indirect pulp capping
Apexification procedures
COMPOSITION
2 Pastes – Base and Catalyst
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73. SETTING REACTION
Calcium hydroxide reacts with the salicylate forming a chelate,
amorphous calcium disalicylate.
Hydroxyl ions from the cement neutralize the acids produced from the
clast cells and create an optimum pH for pyrophosphatase activity
necessary for mineralization.
MANIPULATION
Equal lengths of the 2 pastes are mixed to a uniform color
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75. BIOLOGICAL EFFECTS
Strong Antibacterial Action
Ionic dissociation of calcium hydroxide into calcium ions and
hydroxyl ions. (54.11% and 45.89% respectively)
Hydroxyl ions induces chemical injury on the organic
components of thecytoplasmic membrane of the bacteria,
causing destruction of phospholipids or unsaturated fatty acids.
Dentin Bridge Formation (Pulp Capping)
Activates enzymes such as alkaline mineralization
phosphatase which is responsible for mineralisation
Free calcium hydroxide helps in menaralisation of carious
dentin
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77. CONCLUSION :
No single type of cement satisfies all of the ideal
requirements or is best suited for all indications in dentistry
Each situation must be evaluated based on the
environmental, mechanical and biological factors and finally
decide on which material to be used in each case.
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