A Small effort to make this theory topic a little practical!!
The knowledge of this basic structure is actually the first building block towards dentistry.
Proper knowledge leads to correct diagnosis and henceforth desired treatment.
The document discusses the complex process of tooth development from initiation to eruption. It begins with the formation of the primary epithelial bands and dental lamina between 6-7 weeks in utero, which give rise to the tooth buds. The buds progress through stages of proliferation, histodifferentiation, and morphodifferentiation to form the crown and root structures. Hertwig's epithelial root sheath is responsible for root formation and shape before teeth erupt into the oral cavity.
This document provides an overview of the history and development of rotary dental instruments. It discusses the evolution from early hand-rotated instruments to modern electric and air-driven devices. It also classifies rotary instruments according to design, speed, and cutting bur shape/size. Advantages of rotary instruments include reduced time/operator fatigue and improved precision compared to hand tools. Factors like speed, pressure, heat production, and vibration are also examined.
This document provides information on wrought metal alloys, including how they are made and their common uses and properties. Wrought alloys are cold worked metals that are plastically deformed through mechanical processes like rolling and drawing. This changes their shape and microstructure, improving properties like strength. Common wrought alloys used in dentistry include stainless steels, gold alloys, and titanium alloys. The document discusses the composition and processing of these materials.
This document provides information on the steps of cavity preparation, including defining cavity preparation, the objectives and principles. It describes Black's classification system for cavities in 6 classes. The steps of cavity preparation outlined include obtaining the outline form and initial depth, primary resistance and retention forms, and convenience form. It also discusses final cavity preparation steps like removing remaining decay, providing pulp protection, and finishing enamel walls and margins.
The document discusses the fundamentals of cavity preparation, including its definition, objectives, and historical development. It covers factors that affect cavity preparation as well as terminology, classification, and the stages of initial and final tooth preparation. The key principles of cavity preparation are to remove all defective tooth structure, protect the pulp, and provide retention for the restorative material. Modern cavity preparation techniques favor prevention of extension and minimal intervention.
Tooth eruption involves three phases:
1. The pre-eruptive phase involves tooth germ development and movement within the jaw bone.
2. The eruptive phase is when the tooth emerges into the mouth through the gums and reaches the bite.
3. The post-eruptive phase occurs after the tooth has reached the bite, and involves minor movements like accommodating jaw growth and bite wear.
Tooth eruption is guided by several theories centered around root formation, bone remodeling, the dental follicle, and ligament and blood vessel forces, but is likely multifactorial. Clinical considerations for eruption include early or delayed timing.
Cementum is the mineralized tissue covering dental roots. It begins at the cementoenamel junction and continues to the root apex. Cementum provides attachment for collagen fibers (Sharpey's fibers) that bind the tooth to surrounding structures. Cementum develops in two stages: the prefunctional stage involving matrix formation and mineralization, and the functional stage where cementum deposition continues throughout life in response to tooth movement and wear. Cementum comes in various forms classified by development, cellularity, and fiber origin and includes acellular, cellular, intrinsic and extrinsic fiber cementum.
The document discusses the complex process of tooth development from initiation to eruption. It begins with the formation of the primary epithelial bands and dental lamina between 6-7 weeks in utero, which give rise to the tooth buds. The buds progress through stages of proliferation, histodifferentiation, and morphodifferentiation to form the crown and root structures. Hertwig's epithelial root sheath is responsible for root formation and shape before teeth erupt into the oral cavity.
This document provides an overview of the history and development of rotary dental instruments. It discusses the evolution from early hand-rotated instruments to modern electric and air-driven devices. It also classifies rotary instruments according to design, speed, and cutting bur shape/size. Advantages of rotary instruments include reduced time/operator fatigue and improved precision compared to hand tools. Factors like speed, pressure, heat production, and vibration are also examined.
This document provides information on wrought metal alloys, including how they are made and their common uses and properties. Wrought alloys are cold worked metals that are plastically deformed through mechanical processes like rolling and drawing. This changes their shape and microstructure, improving properties like strength. Common wrought alloys used in dentistry include stainless steels, gold alloys, and titanium alloys. The document discusses the composition and processing of these materials.
This document provides information on the steps of cavity preparation, including defining cavity preparation, the objectives and principles. It describes Black's classification system for cavities in 6 classes. The steps of cavity preparation outlined include obtaining the outline form and initial depth, primary resistance and retention forms, and convenience form. It also discusses final cavity preparation steps like removing remaining decay, providing pulp protection, and finishing enamel walls and margins.
The document discusses the fundamentals of cavity preparation, including its definition, objectives, and historical development. It covers factors that affect cavity preparation as well as terminology, classification, and the stages of initial and final tooth preparation. The key principles of cavity preparation are to remove all defective tooth structure, protect the pulp, and provide retention for the restorative material. Modern cavity preparation techniques favor prevention of extension and minimal intervention.
Tooth eruption involves three phases:
1. The pre-eruptive phase involves tooth germ development and movement within the jaw bone.
2. The eruptive phase is when the tooth emerges into the mouth through the gums and reaches the bite.
3. The post-eruptive phase occurs after the tooth has reached the bite, and involves minor movements like accommodating jaw growth and bite wear.
Tooth eruption is guided by several theories centered around root formation, bone remodeling, the dental follicle, and ligament and blood vessel forces, but is likely multifactorial. Clinical considerations for eruption include early or delayed timing.
Cementum is the mineralized tissue covering dental roots. It begins at the cementoenamel junction and continues to the root apex. Cementum provides attachment for collagen fibers (Sharpey's fibers) that bind the tooth to surrounding structures. Cementum develops in two stages: the prefunctional stage involving matrix formation and mineralization, and the functional stage where cementum deposition continues throughout life in response to tooth movement and wear. Cementum comes in various forms classified by development, cellularity, and fiber origin and includes acellular, cellular, intrinsic and extrinsic fiber cementum.
This document outlines the 9 steps in cavity preparation for class I dental restorations:
1. Outlining the cavity and initial depth preparation.
2. Developing the primary resistance form to withstand forces.
3. Adding primary retention features like cavity convergence.
4. Adding convenience features for restoration placement.
5. Removing infected material and old restorations.
6. Applying pulp protection as needed.
7. Adding secondary resistance and retention features like bonding agents.
8. Finishing external walls for optimal margins.
9. Cleaning, inspecting, and sealing the preparation prior to restoration.
The document discusses the principles of tooth preparation for dental restorations. It describes the purposes of tooth preparation which are to repair damaged tooth structure and maintain proper form, function and esthetics. The document outlines the different types of restorations and factors to consider for tooth preparation. It explains terminology related to tooth preparation such as simple, compound and complex preparations. Key steps in tooth preparation are described including establishing the outline form, primary resistance and retention forms, and convenience form. Methods to provide pulp protection and improve resistance and retention forms are also summarized.
Permanent Mandibular First Premolar and Differences between First and Second ...Dr Monika Negi
This document provides information about the permanent mandibular first premolar and differences between the mandibular first and second premolars. It discusses the general features of premolars, including their transitional location between canines and molars. For the mandibular first premolar, it describes the chronology, number of roots, crown and root outlines, contact areas, and surface anatomy from various aspects. It then compares the mandibular first and second premolars, noting differences in their geometric outlines, facial outlines and surface anatomy, lingual outlines, proximal outlines, occlusal aspects, and pulp cavities.
This document discusses physiologic tooth movement including eruption and shedding. It describes the three phases of tooth movement: preeruptive, eruptive, and posteruptive. Preeruptive movement occurs before eruption as tooth germs shift within the jaw. Eruptive movement brings teeth into occlusion from within bone. Posteruptive movement maintains tooth position as jaws grow. Theories for the mechanisms driving eruption include root growth, bone remodeling, periodontal ligament traction, and vascular pressure. Tooth eruption follows a chronological sequence in both the primary and permanent dentitions.
Matrices are used in operative dentistry to support and give form to dental restorations during placement and hardening. The document discusses the importance of matrices, their functions and characteristics of a good matrix. It describes different types of matrices including metallic matrices like Tofflemire, automatrix and sectional matrices like Palodent. Techniques for proper matrix selection, adaptation and wedge placement are also covered.
This document summarizes tooth eruption, including the physiological phases and mechanisms involved. It discusses preeruptive, eruptive, and posteruptive tooth movement and the histological changes that occur during each phase, such as root formation, remodeling of the bony crypt, and traction of the periodontal ligament. Key cellular and molecular events like the roles of PTHrP, EGF, and TGF-α are outlined. The chronology of eruption of the primary and permanent dentition is presented, as well as clinical considerations like natal teeth, teething, and impacted or submerged teeth.
This document provides information on the anatomy of permanent mandibular molars. It describes the identifying features, anatomical aspects, and differences between upper and lower molars for the mandibular first, second, and third molars. Key details include the number and shape of cusps, developmental grooves, roots, and contact areas for each tooth. Differences between upper and lower molars are also summarized such as the number of roots, presence of an oblique ridge, and shape of cusps on the mesial aspect.
This document provides a summary of the history, etiology, histopathogenesis, and clinical types of dental caries. It discusses how caries has been viewed since ancient times, including early beliefs that worms caused decay. Archaeological evidence shows caries has affected humans for thousands of years. Major increases occurred with the rise of agriculture and sugar consumption. Current understanding identifies plaque bacteria, fermentable carbohydrates, and their acid byproducts as the primary causes of enamel demineralization and caries development. The document reviews various theories proposed over time and classifies caries according to location, extent, rate, and other features.
A detailed look at the differences between the human primary and permanent dentition. Hope you find this informative. for further queries, please contact at dr.mathewthomasm@gmail.com.
Cementum is the mineralized tissue covering the roots of teeth that provides attachment for collagen fibers linking the tooth to surrounding bone. It begins at the cementoenamel junction and continues along the root to the apex. Cementum is avascular and less hard than dentin. It contains both inorganic minerals and organic materials including collagen. Cementoblast cells synthesize cementum by laying down an organic matrix that subsequently mineralizes. Cementum thickness varies along the root and increases with age. It provides for functional adaptation and resistance to resorption during orthodontic tooth movement.
A Complete presentation explaining the complete morphology of Maxillary first molar, for the benefit of people like me who tried and failed to find everything in one package
The periodontal ligament is the soft connective tissue between the cementum and alveolar bone. It has an hourglass shape that is thinnest in the middle and widens coronally and apically. During tooth eruption, fibroblasts produce collagen fibers that develop into principal fiber groups including the transseptal, alveolar crest, horizontal, oblique, apical, and interradicular fibers. The periodontal ligament contains collagen fibers, cellular elements like fibroblasts, and ground substances such as glycosaminoglycans. It functions to support the tooth, sense pressure, and maintain attachment through Sharpey's fibers embedded in the cementum and bone.
This document summarizes the process of tooth eruption. It discusses the pre-eruptive, eruptive, and post-eruptive phases of tooth movement. During the pre-eruptive phase, tooth germs move within the jaw before eruption. The eruptive phase involves tooth movement from within the bone to the oral cavity. Post-eruptive movements maintain tooth position as the jaws grow. Theories on the mechanisms controlling eruption and resorption are also presented, along with cellular and molecular factors such as the dental follicle that regulate eruption.
Fundamentals in tooth preparation, Now many indications for treatment for teeth are not due to caries and, therefore, the preparation of the tooth is no longer referred to as cavity preparation but as tooth preparation, and the term cavity is used only as a historical reference.
NOMENCLATURE
Cementum is the calcified tissue that covers the root surface of teeth. It is less calcified and harder than dentin. Cementum is classified based on the presence or absence of cells and fibers. Cellular cementum contains cementocytes within lacunae and forms later in life, while acellular cementum lacks cells and forms earlier. Cementum is deposited throughout life to maintain tooth structure and plays an important role in tooth attachment through Sharpey's fibers inserting into the cementum. Cementum can undergo resorption and repair in response to environmental changes and maintains tooth integrity under forces.
Dentinogenesis is the formation of dentin, which begins before enamel formation. Dentin is formed by odontoblast cells in two phases: first the formation of an organic collagen matrix, followed by deposition of hydroxyapatite crystals. As dentinogenesis begins, odontoblasts elongate and secrete an unmineralized collagen matrix called predentin. Over time, predentin adjacent to the pulp mineralizes and forms dentin while new predentin is deposited, resulting in incremental dentin growth of approximately 4 micrometers per day. Dentinogenesis continues throughout life but slows after eruption.
This document describes various anatomical structures found on teeth. It discusses structures such as cusps, tubercles, cingulum, ridges, inclined planes, fossae, grooves, and pits. Cusps are pointed projections found on posterior teeth that form the biting surfaces. Tubercles are small enamel extensions that can form due to trauma or disease. Ridges are convex elevations along tooth surfaces like marginal ridges along the edges. Fossae are irregular depressions found on tooth crowns. Grooves mark divisions between developmental lobes and pits are found at groove junctions.
Cementum is the mineralized tissue covering tooth roots. It consists of inorganic minerals like hydroxyapatite and organic materials like collagen. Cementum forms through cementogenesis, led by cementoblasts. There are two stages of cementogenesis - matrix formation where cementoblasts lay down an unmineralized matrix, and mineralization where crystals are deposited. Cementum can be classified as acellular or cellular based on the presence of cementocytes, and primary or secondary based on formation time. Cementum functions to attach teeth to bone and allows for adaptation.
This document discusses various developmental disturbances that can affect the size, shape, number and structure of teeth. Regarding size, it describes microdontia where teeth are smaller than normal, and macrodontia where teeth are larger. For shape, it discusses anomalies such as gemination, fusion, concrescence and dilaceration. It also covers rare formations like talon cusps, dens in dente and dens evaginatus. The number of teeth can be affected by complete anodontia where no teeth form, or supernumerary teeth where extra teeth are present. Radiographic and clinical features of each condition are provided along with potential causes and treatments.
The document summarizes the key anatomical features of the permanent maxillary molars. It describes the first, second, and third maxillary molars, focusing on their roots, cusps, occlusal outlines, and distinguishing characteristics. The first molar is the largest with well-developed roots and cusps. The second molar is smaller with less divergent roots. The third molar is the smallest with shorter, often fused roots and variable occlusal morphology including sometimes absent cusps or congenitally missing teeth.
This document provides an overview of the structure and properties of enamel. It discusses the physical and chemical composition of enamel, including its high mineral content and hydroxyapatite crystals. It describes the microscopic structure of enamel, including enamel rods, interrod enamel, and surface features like striations of Retzius. It also summarizes the life cycle of ameloblasts and the process of amelogenesis. Bleaching effects on enamel and developmental disturbances are briefly covered.
Enamel defects can be caused by disturbances during enamel development and mineralization. The document discusses the history of understanding enamel defects and the life cycle of ameloblasts, which produce enamel. It describes how factors like infections, nutritional deficiencies, and other illnesses during tooth development can disrupt ameloblast activity and cause hypoplasia, hypomineralization, or hypomaturation. The severity and duration of the disturbance determines if it results in enamel absence, improper calcification, or other defects. Maternal health, nutrition and illnesses can also affect enamel development in utero and after birth.
This document outlines the 9 steps in cavity preparation for class I dental restorations:
1. Outlining the cavity and initial depth preparation.
2. Developing the primary resistance form to withstand forces.
3. Adding primary retention features like cavity convergence.
4. Adding convenience features for restoration placement.
5. Removing infected material and old restorations.
6. Applying pulp protection as needed.
7. Adding secondary resistance and retention features like bonding agents.
8. Finishing external walls for optimal margins.
9. Cleaning, inspecting, and sealing the preparation prior to restoration.
The document discusses the principles of tooth preparation for dental restorations. It describes the purposes of tooth preparation which are to repair damaged tooth structure and maintain proper form, function and esthetics. The document outlines the different types of restorations and factors to consider for tooth preparation. It explains terminology related to tooth preparation such as simple, compound and complex preparations. Key steps in tooth preparation are described including establishing the outline form, primary resistance and retention forms, and convenience form. Methods to provide pulp protection and improve resistance and retention forms are also summarized.
Permanent Mandibular First Premolar and Differences between First and Second ...Dr Monika Negi
This document provides information about the permanent mandibular first premolar and differences between the mandibular first and second premolars. It discusses the general features of premolars, including their transitional location between canines and molars. For the mandibular first premolar, it describes the chronology, number of roots, crown and root outlines, contact areas, and surface anatomy from various aspects. It then compares the mandibular first and second premolars, noting differences in their geometric outlines, facial outlines and surface anatomy, lingual outlines, proximal outlines, occlusal aspects, and pulp cavities.
This document discusses physiologic tooth movement including eruption and shedding. It describes the three phases of tooth movement: preeruptive, eruptive, and posteruptive. Preeruptive movement occurs before eruption as tooth germs shift within the jaw. Eruptive movement brings teeth into occlusion from within bone. Posteruptive movement maintains tooth position as jaws grow. Theories for the mechanisms driving eruption include root growth, bone remodeling, periodontal ligament traction, and vascular pressure. Tooth eruption follows a chronological sequence in both the primary and permanent dentitions.
Matrices are used in operative dentistry to support and give form to dental restorations during placement and hardening. The document discusses the importance of matrices, their functions and characteristics of a good matrix. It describes different types of matrices including metallic matrices like Tofflemire, automatrix and sectional matrices like Palodent. Techniques for proper matrix selection, adaptation and wedge placement are also covered.
This document summarizes tooth eruption, including the physiological phases and mechanisms involved. It discusses preeruptive, eruptive, and posteruptive tooth movement and the histological changes that occur during each phase, such as root formation, remodeling of the bony crypt, and traction of the periodontal ligament. Key cellular and molecular events like the roles of PTHrP, EGF, and TGF-α are outlined. The chronology of eruption of the primary and permanent dentition is presented, as well as clinical considerations like natal teeth, teething, and impacted or submerged teeth.
This document provides information on the anatomy of permanent mandibular molars. It describes the identifying features, anatomical aspects, and differences between upper and lower molars for the mandibular first, second, and third molars. Key details include the number and shape of cusps, developmental grooves, roots, and contact areas for each tooth. Differences between upper and lower molars are also summarized such as the number of roots, presence of an oblique ridge, and shape of cusps on the mesial aspect.
This document provides a summary of the history, etiology, histopathogenesis, and clinical types of dental caries. It discusses how caries has been viewed since ancient times, including early beliefs that worms caused decay. Archaeological evidence shows caries has affected humans for thousands of years. Major increases occurred with the rise of agriculture and sugar consumption. Current understanding identifies plaque bacteria, fermentable carbohydrates, and their acid byproducts as the primary causes of enamel demineralization and caries development. The document reviews various theories proposed over time and classifies caries according to location, extent, rate, and other features.
A detailed look at the differences between the human primary and permanent dentition. Hope you find this informative. for further queries, please contact at dr.mathewthomasm@gmail.com.
Cementum is the mineralized tissue covering the roots of teeth that provides attachment for collagen fibers linking the tooth to surrounding bone. It begins at the cementoenamel junction and continues along the root to the apex. Cementum is avascular and less hard than dentin. It contains both inorganic minerals and organic materials including collagen. Cementoblast cells synthesize cementum by laying down an organic matrix that subsequently mineralizes. Cementum thickness varies along the root and increases with age. It provides for functional adaptation and resistance to resorption during orthodontic tooth movement.
A Complete presentation explaining the complete morphology of Maxillary first molar, for the benefit of people like me who tried and failed to find everything in one package
The periodontal ligament is the soft connective tissue between the cementum and alveolar bone. It has an hourglass shape that is thinnest in the middle and widens coronally and apically. During tooth eruption, fibroblasts produce collagen fibers that develop into principal fiber groups including the transseptal, alveolar crest, horizontal, oblique, apical, and interradicular fibers. The periodontal ligament contains collagen fibers, cellular elements like fibroblasts, and ground substances such as glycosaminoglycans. It functions to support the tooth, sense pressure, and maintain attachment through Sharpey's fibers embedded in the cementum and bone.
This document summarizes the process of tooth eruption. It discusses the pre-eruptive, eruptive, and post-eruptive phases of tooth movement. During the pre-eruptive phase, tooth germs move within the jaw before eruption. The eruptive phase involves tooth movement from within the bone to the oral cavity. Post-eruptive movements maintain tooth position as the jaws grow. Theories on the mechanisms controlling eruption and resorption are also presented, along with cellular and molecular factors such as the dental follicle that regulate eruption.
Fundamentals in tooth preparation, Now many indications for treatment for teeth are not due to caries and, therefore, the preparation of the tooth is no longer referred to as cavity preparation but as tooth preparation, and the term cavity is used only as a historical reference.
NOMENCLATURE
Cementum is the calcified tissue that covers the root surface of teeth. It is less calcified and harder than dentin. Cementum is classified based on the presence or absence of cells and fibers. Cellular cementum contains cementocytes within lacunae and forms later in life, while acellular cementum lacks cells and forms earlier. Cementum is deposited throughout life to maintain tooth structure and plays an important role in tooth attachment through Sharpey's fibers inserting into the cementum. Cementum can undergo resorption and repair in response to environmental changes and maintains tooth integrity under forces.
Dentinogenesis is the formation of dentin, which begins before enamel formation. Dentin is formed by odontoblast cells in two phases: first the formation of an organic collagen matrix, followed by deposition of hydroxyapatite crystals. As dentinogenesis begins, odontoblasts elongate and secrete an unmineralized collagen matrix called predentin. Over time, predentin adjacent to the pulp mineralizes and forms dentin while new predentin is deposited, resulting in incremental dentin growth of approximately 4 micrometers per day. Dentinogenesis continues throughout life but slows after eruption.
This document describes various anatomical structures found on teeth. It discusses structures such as cusps, tubercles, cingulum, ridges, inclined planes, fossae, grooves, and pits. Cusps are pointed projections found on posterior teeth that form the biting surfaces. Tubercles are small enamel extensions that can form due to trauma or disease. Ridges are convex elevations along tooth surfaces like marginal ridges along the edges. Fossae are irregular depressions found on tooth crowns. Grooves mark divisions between developmental lobes and pits are found at groove junctions.
Cementum is the mineralized tissue covering tooth roots. It consists of inorganic minerals like hydroxyapatite and organic materials like collagen. Cementum forms through cementogenesis, led by cementoblasts. There are two stages of cementogenesis - matrix formation where cementoblasts lay down an unmineralized matrix, and mineralization where crystals are deposited. Cementum can be classified as acellular or cellular based on the presence of cementocytes, and primary or secondary based on formation time. Cementum functions to attach teeth to bone and allows for adaptation.
This document discusses various developmental disturbances that can affect the size, shape, number and structure of teeth. Regarding size, it describes microdontia where teeth are smaller than normal, and macrodontia where teeth are larger. For shape, it discusses anomalies such as gemination, fusion, concrescence and dilaceration. It also covers rare formations like talon cusps, dens in dente and dens evaginatus. The number of teeth can be affected by complete anodontia where no teeth form, or supernumerary teeth where extra teeth are present. Radiographic and clinical features of each condition are provided along with potential causes and treatments.
The document summarizes the key anatomical features of the permanent maxillary molars. It describes the first, second, and third maxillary molars, focusing on their roots, cusps, occlusal outlines, and distinguishing characteristics. The first molar is the largest with well-developed roots and cusps. The second molar is smaller with less divergent roots. The third molar is the smallest with shorter, often fused roots and variable occlusal morphology including sometimes absent cusps or congenitally missing teeth.
This document provides an overview of the structure and properties of enamel. It discusses the physical and chemical composition of enamel, including its high mineral content and hydroxyapatite crystals. It describes the microscopic structure of enamel, including enamel rods, interrod enamel, and surface features like striations of Retzius. It also summarizes the life cycle of ameloblasts and the process of amelogenesis. Bleaching effects on enamel and developmental disturbances are briefly covered.
Enamel defects can be caused by disturbances during enamel development and mineralization. The document discusses the history of understanding enamel defects and the life cycle of ameloblasts, which produce enamel. It describes how factors like infections, nutritional deficiencies, and other illnesses during tooth development can disrupt ameloblast activity and cause hypoplasia, hypomineralization, or hypomaturation. The severity and duration of the disturbance determines if it results in enamel absence, improper calcification, or other defects. Maternal health, nutrition and illnesses can also affect enamel development in utero and after birth.
Enamel presentation. prepared by mohammed yahiaMaher Aziz
This document discusses the structure and formation of enamel. It begins by defining enamel and outlining its formation through the stages of odontogenesis and amelogenesis. Key details are provided on the histological layers involved in enamel formation, as well as the life cycle of ameloblasts. The physical and chemical properties of enamel are then examined, including its hardness, permeability and solubility. The document concludes by describing various histological features of enamel such as enamel rods, striations of Retzius, and the dentino-enamel junction.
The document discusses the development of teeth from the dental lamina stage through the various bell stages. It describes how the enamel organ, dental papilla, and dental sac form and their roles in tooth development. The stages of tooth development including bud, cap, and bell stages are summarized. Clinical conditions related to abnormalities in tooth development like dentinogenesis imperfecta, Hutchinson's incisor, and fusion are also mentioned.
Enamel significance in operative dentistry /certified fixed orthodontic cour...Indian dental academy
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The deciduous teeth, also known as baby teeth, are replaced through a process called shedding. Shedding occurs as the roots of the deciduous teeth are resorbed by osteoclasts in preparation for the eruption of the permanent teeth. It typically begins around age 5-8 years for anterior teeth and progresses posteriorly. Odontoclasts are large, multinucleated cells that resorb dental hard tissues through secretion of acids and enzymes. Abnormalities can include retained or impacted deciduous teeth.
Enamel is the hardest tissue in the human body that covers the anatomical crown of a tooth. It is made up of hydroxyapatite crystals arranged in enamel rods or prisms. Enamel provides protection to the underlying dentin and allows for chewing and grinding of food. It is formed by ameloblasts, which deposit an organic matrix that mineralizes into enamel. Enamel can demineralize from acid produced by bacteria, leading to dental caries if left untreated.
The document summarizes key aspects of dentin:
- Dentin is a bonelike tissue that makes up the bulk of teeth beneath enamel. It contains dentinal tubules that branch throughout its thickness.
- Dentin's physical properties include a light yellow color that darkens with age and a hardness between enamel and bone. Chemically, it is composed mostly of hydroxyapatite and collagen.
- Histologically, dentin contains dentinal tubules, peritubular dentin surrounding the tubules, intertubular dentin between tubules, and incremental lines that indicate its growth. The tubule density is highest near the pulp.
The document discusses the development of primary and permanent dentition from initiation to eruption. It begins with the formation of the dental lamina from the oral epithelium at 7 weeks in utero. Tooth buds develop from thickening of the dental lamina. Primary teeth begin calcifying at 14 weeks and erupt between 6 months to 2 years of age. Eruption is mediated by theories including bone remodeling, root formation, vascular pressure, and periodontal ligament traction. The primary dentition establishes juvenile occlusal equilibrium until the first permanent molars erupt around 6 years of age.
Nomenclature, eruption and shedding of teeth.pptxDrBerinDhanya
The document discusses nomenclature, eruption, and shedding of teeth. It begins with an introduction and then covers topics like dental formulae for mammalian teeth, different tooth numbering systems, and the stages of tooth eruption including pre-eruptive, eruptive, and post-eruptive movement. It also discusses factors controlling eruption, theories of eruption, cellular events in eruption, and the process of tooth shedding.
Age changes in enamel, dentin and pulp1.pptxrichanaina28
As teeth age, several changes occur in the major tissues:
- Enamel becomes darker, develops cracks, and increases in mineral content, making it more resistant to decay. Dentin also increases in mineral content, forming secondary dentin and occluding dentinal tubules. This decreases pulp size and sensitivity. The pulp exhibits decreased cellularity, vascularity, and reparative ability with age. These anatomical and physiological changes are natural aging processes that can impact dental treatment for older patients.
This document discusses young permanent teeth and their characteristics compared to mature teeth. It notes that young permanent teeth are those that have recently erupted and have not completed root development and closure of the apical foramen. The root development process can take 2-3 years after eruption. These young teeth are still developing and possess stem cells that can aid in continued root development. Factors like deep caries or trauma can lead to pulp necrosis in an immature tooth and result in an open apex. The document also discusses various classifications and stages of root development in young permanent teeth.
1. Tooth development begins around the 6th week of gestation with the formation of the primary epithelial band, which divides into the dental lamina and vestibular lamina.
2. Teeth develop through a series of stages from bud to bell shaped to advanced bell stage when mineralization begins and root formation commences.
3. The dental lamina gives rise to the tooth buds and plays a role in shaping tooth development through later stages. The enamel organ and dental papilla are structures that form within the developing tooth bud.
The document discusses the development of primary and permanent dentition in humans. It describes the characteristics of human dentition including dental formula. Tooth development occurs in three stages - bud, cap and bell stage. The primary teeth erupt in a sequence from 6-30 months. Characteristics of primary dentition include spacing, shallow overjet and overbite, and vertical inclination of anterior teeth. Molar relationships in primary dentition can be flush, mesial step or distal step.
The document summarizes the development of teeth from the formation of the dental lamina to the bell stages of tooth development. It discusses how the dental lamina divides into the dental lamina and vestibular lamina, leading to the formation of the enamel organ and dental papilla/dental sac. It describes the three morphological stages of tooth development - bud stage, cap stage, and bell stage - and the histological changes that occur during each stage, including the differentiation of ameloblasts and odontoblasts.
This document discusses the development of teeth from the dental lamina. It begins with the formation of the primary epithelial band in the 6th week of development, which later divides into the dental lamina and vestibular lamina. Tooth development then progresses through stages including the bud stage, cap stage, bell stage, and advanced bell stage. It also discusses root formation mediated by Hertwig's epithelial root sheath, as well as clinical considerations like anomalies in tooth number, shape, and enamel formation.
This document discusses various aspects of tooth eruption including:
- Tooth eruption involves the movement of teeth from their developmental positions in the jaws to their functional positions in the oral cavity.
- Eruption occurs in three stages - preeruptive, eruptive, and posteruptive. Key events in each stage are described.
- Several theories have been proposed to explain the mechanisms underlying tooth eruption, including root growth, alveolar bone formation, periodontal ligament traction, and vascular pressure. However, tooth eruption is now considered a multifactorial process.
- The dental follicle plays a key role in eruption through directing bone remodeling and resorption to form an eruption pathway
Chronology of dental development and development of occlusionshilpathaklotra
The document summarizes key stages of dental development and changes in dental arches:
- Tooth development begins with thickening of oral epithelium, forming the primary epithelial band that invades underlying mesenchyme. This forms the dental lamina which serves as the primordium for deciduous teeth.
- Teeth develop through bud, cap, bell, and advanced bell stages. During these stages, the enamel organ and dental papilla form and cells differentiate into ameloblasts and odontoblasts. Enamel knots organize cuspal morphogenesis.
- Root formation begins after crown formation is complete, guided by Hertwig's epithelial root sheath which induces dentin formation and shapes
1. The document describes the morphological stages of tooth development from the dental lamina stage through the bell stage.
2. It explains the histological changes that occur in each stage, including the differentiation of cells in the enamel organ and dental papilla.
3. Root formation begins after enamel and dentin deposition reaches the cemento-enamel junction, guided by the epithelial root sheath of Hertwig.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
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Enamel the basic!
1. ENAMEL-
THE BASIC
D R S H R E Y A S I N G H
1 S T Y E A R P G T
D E P A R T M E N T O F P E D I A T R I C A N D P R E V E N T I V E D E N T I S T R Y
2. CONTENTS
• INTRODUCTION
• ORIGIN
• PHYSICAL CHARACTERISTICS
• CHEMICAL CHARACTERISTICS
• AGE CHANGES
• CLINICAL CONSIDERATIONS
• DEFECTS IN ENAMEL
• ENAMEL REGENERATION
• NEWER ADVANCES
• TAKE HOME MESSAGE
• REFERENCES
3. H A R D E S T
B I O L O G I C A L T I S S U E
I N T H E B O D Y !
The anatomic crown of a tooth is covered by
acellular , avascular , highly mineralized material
known as ENAMEL.
5. E N A M E L I S D E R I V E D
F R O M A G E R M A N
W O R D
“ S M E L Z A N ” M E A N I N G
D I F F I C U LT T O M E LT.
ORIGIN
• Hipprocates (460–370)
• Blake (1801) called enamel the ‘cortex
striatus’ because it was composed of
innumerable fibres.
• Classified teeth as bones but realised
that teeth differed from bone by being
harder.
Reference: Trenouth M; the origin of terms of enamel
FACULTY OF DENTAL JOURNAL 2014:5(1)
6. PRIMARY
EPITHELIAL
BAND
DEVELOPMENT OF ENAMEL
At about 6th week of development,
certain areas of basal cells of oral
ectoderm proliferate at a more
rapid rate than adjacent areas.
There is condensation of the
mesenchymal tissue and of
capillary network beneath the
proliferating epithelium.
The thickened oral epithelium
invaginates into the mesenchyme to
for PRIMARY EPITHELIAL BAND.
REFERNCE:
Physical characteristics Textbook of oral histology&embryology:Orban Blaint:13th Edition.
7. by 7th week of IUL the primary
epithelial bend divides into two
processes by invagination of
underlying ectomesenchyme
bucally located is the vestibular
lamina and lingually located is
the dental lamina
the vestibular lamina contributes
to development of teeth and
dental lamina to the development
of teeth.
REFERNCE:
Physical characteristics Textbook of oral histology&embryology:Orban Blaint:13th
Edition.
in the late bell stage by 18th week of
IUL dental hard tissues start to form
9. DEVELOPMENT OF ENAMEL
• Ameloblasts are differentiated from inner enamel epithelium.
• Under the inductive influence of ameloblasts, the adjacent cells of dental
papilla are differentiated to odontoblasts which lay down a layer of
dentin along membrana performativa.
• The dentin then induces the ameloblasts to intitate their secretory
activities.
Reciprocal dependence
11. LIFE CYCLE OF AMELOBLASTS
Morphogenic
stage
Organising
stage
Formative
stage
Maturative
stage
Protective
stage
desmolytic
stage
12. MORPHOGENIC STAGE
• Morphogenic stage Interaction of ameloblast with the the
adjacent mesenchymal cells, determines the shape of
the DEJ.
• Short and columnar cells , with large oval nuclei that
almost fill the cell body.
• The Golgi apparatus and the centriole are located in the
proximal end of the cell,
• The mitochondria are evenly dispersed throughout
the cytoplasm.
REFERENCE : TENCATE’S ORAL HISTOLOGY 9TH EDITION
13. ORGANIZING STAGE
• The inner enamel epithelium interacts with the
adjacent connective tissue cells odontoblasts.
• The cells become elongated in size.
• Reversal of the functional polarity of these
cells takes place by the migration of the
centrioles and Golgi regions from the proximal
ends of the cells into their distal ends.
• The clear cell-free zone between the inner
enamel epithelium and the dental papilla
disappears.
REFERENCE : TENCATE’S ORAL HISTOLOGY 9TH EDITION
14. ORGANIZING STAGE
• During this stage the formation of the dentin by the odontoblasts
begins.
• This cuts off the ameloblasts from their original source of nourishment.
• This reversal of nutritional source is characterized by proliferation of
capillaries of the dental sac and gradual disappearance of the stellate
reticulum.
REFERENCE : TENCATE’S ORAL HISTOLOGY 9TH EDITION
15. FORMATIVE STAGE
• Ameloblasts enter their formative stage after the first
layer of dentin has been formed.
• During formation of the enamel matrix the ameloblasts
retain approximately the same length and
arrangement.
• The earliest apparent change is the development of
blunt cell processes on the ameloblast surfaces,
which penetrate the basal lamina and enter the
predentin.
REFERENCE : TENCATE’S ORAL HISTOLOGY 9TH EDITION
16. MATURATIVE STAGE
• Occurs after most of the thickness of the enamel matrix has
been formed in the occlusal or incisal area.
• The ameloblasts are slightly reduced in length and are
closely attached to enamel matrix.
• Stratum intermedium lose their cuboidal shape and
regular arrangement and assume a spindle shape.
• Ameloblasts display microvilli and cytoplasmic
vacuoles containing material resembling enamel matrix are
present.
• These structures indicate an absorptive function of these
cells.
REFERENCE : TENCATE’S ORAL HISTOLOGY 9TH EDITION
17. PROTECTIVE STAGE
• Formation of the reduced enamel
epithelium.
• Its function is of protecting the mature
enamel by separating it from the connective
tissue until the tooth erupts.
REE = IEE +OEE +
SI
REFERENCE : TENCATE’S ORAL HISTOLOGY 9TH EDITION
18. DESMOLYTIC STAGE
• The reduced enamel epithelium after proliferation induces
atrophy of the connective tissue separating it from the oral
epithelium.
• The epithelial cells elaborate
• Enzymes that are able to destroy connective tissue fibres by
desmolysis.
• Premature degeneration of the reduced enamel epithelium may
prevent the eruption of a tooth.
REFERENCE : TENCATE’S ORAL HISTOLOGY 9TH EDITION
20. DID YOU KNOW?
• During protective phase, the composition of enamel can still be modified.
• Fluoride can be incorporated into the enamel of an unerupted
tooth!
• In children younger than 6 years fluoride is incorporated into the enamel of permanent
teeth, making the teeth more resistant to the action of bacterial and acids in food.
REFERENCE ;Tapias MA, De Miguel G, Jimenez-Garcia R, Gonzalez A, Dominguez V. Incidence of caries in an
population in Mostoles, Madrid. Evaluation of a preventive program after 7.5 years of follow-up. Int J
Pediatr. 2001;11(6):440–446. [PubMed] [Google Scholar]
THIS MAYBE THE BEST WAY TO PREVENT CAVITIES!!!
22. THICKNESS
• On the cusps of human molars and
premolars the enamel attains a maximum
thickness of 2 to 2.5 mm, thinning down to
almost a knife edge at the neck of the the
tooth.
Refernce:The hardness of enamel and dentine. E. Newbrunt and W.Pigman. AustralTrenouthian Dental Journal, August, 1960
23. HARDNESS
• Hardness of enamel varies from 5-8 moh
• Enamel is the hardest calcified tissue in the human body i.e. 296 KHN .
• Its function is to form a resistant covering of the teeth, rendering them suitable for
mastication.
• Atkinson et al stated that deciduous teeth were hardest of all and that permanent
teeth soften with age.
Refernce:The hardness of enamel and dentine. E. Newbrunt and W.Pigman. AustralTrenouthian Dental Journal,
24. DENSITY
• It varies from 3 to 2.84gm/ml
• Density decreases from surface to DEJ.
• Permanent teeth are denser than deciduos teeth
Refernce:The hardness of enamel and dentine. E. Newbrunt and W.Pigman. AustralTrenouthian Dental Journal,
25. COLOUR
• The color of the enamel ranges from yellowish white to greyish white to bluish white.
• It is determined by differences in the translucency of enamel.
• Why is teeth yellow? Yellowish teeth have a thin, translucent enamel through which
the yellow colour of the dentin is visible and greyish teeth have more opaque enamel.
• The translucency may be attributable to variations in the degree of calcification and
homogeneity of the enamel.
Ref: Translucency of Human Dental Enamel R.H.W. Brodbelt et al J DENT RES 1981 60: 1749
Primary teeth are lighter in color, generally bluish white.
26. WHAT IS OPAQUE ENAMEL
• That means opacity is actually a
hypomineralisation or
hypocalcification defect that
ultimately causes alteration in
translucency of enamel.
28. BIREFRINGENCE
Double refraction
This is an optical property of a
material.
The refractive index of these
materials depend upon
propagation and polarization of
light passing through it.
29. DISSOLUTION BY ACIDS IS FASTER IN
DEEPER LEVELS OF ENAMEL
• The core of the crystals are richer in
Mg and carbonate and this accounts
for their greater solubility in acids
than the peripheral portions.
• Conc. Of fluoride increases from
dentine towards surface.
Mg
F
30. PERMEABILITY
• Enamel is selectively permeable.
• It has been found with radioactive tracers that it acts as a semi permeable membrane,
permitting complete or partial passage of certain molecules: like14C-labeled urea.
Ref ;Textbook of oral histology&embryology:Orban Blaint:13th Edition.
SOLUBILITY
•Enamel dissolves in acidic medium.
•The surface enamel is more resistant to dissolution in acidic meidia
than deeper surfaces.
CRITICAL PH 5.5
31. MODULUS OF ELASTICITY
• Modulus of elasticity is 83 GPa
• High modulus of elasticity and low tensile strength.
• On comparing the mechanical properties of the occlusal surface to the DEJ ,MOE at the
surface is higher than that at the DEJ.
RIGID BRITTLE
Refernce:The hardness of enamel and dentine. E. Newbrunt and W.Pigman. AustralTrenouthian Dental Journal,
32. OTHER PROPERTIES
• The specific gravity of deciduous teeth is 2.95 and
permanent teeth is 2.8-3.1
•Enamel is a non electrical conductive material.
•Temperature resistance of enamel measured by AC
impedance spectroscopy, is in the frequency range from
5 to 13 Hz.
•Electrical resistance ranges from 1015 to 105 ohms.
Refernce:The hardness of enamel and dentine. E. Newbrunt and W.Pigman. AustralTrenouthian Dental Journal,
40. DEXTROFLEXION AND
SINISTROFLEXION
Groups of rods after leaving DEJ
curve gently to right(dextroflexion)
After following a straight course for
some distance again curve gently
to left (sinistroflexion)
DEJ
42. •Each enamel rod is tightly packed with
crystallites.
•The mature crystals are ribbon like or
hexagonal with avg size of 1,600A(L)
*300A(B)*900A(W)
•The crystals are arranged parallel to the long
axis of rod head and deviate at about 65
degree in the tail region.
CRYSTALLINE STRUCTURE OF
ENAMEL RODS
When cut longitudinally sections pass through the
“heads” or “bodies” of one row of rods and the “tails”
of an adjacent row. They are 5 μm in breadth and 9
μm in length.
44. CLINICAL THOUGHT
• Ideal cavity wall should have the
following features:-
• Enamel rods which form
cavosurface angle must have their
inner ends on sound dentin.
• Outer ends - covered by restorative
material by giving a bevel (for cast
gold, DFG)
• Enamel walls should be parallel to
the length of the rods (for amalgam)
45. STRIATIONS
Each enamel rod is built up of segments separated
by dark lines that give it a striated appearance . •
The rods are segmented because:
the enamel matrix is formed in a rhythmic manner
and have an uniform length of about 4 μm.
These are areas of disturbed calcifications
Optical effect due to crystalline orientation
Tertiary curve with periodicity at about 4 μm.
47. INTERROD SUBSTANCE
• Rods are semented together by interrod substance.
• Is an extension or the tail of adjacent rod.
• Hypocalcified more of organic substance.
48. INCREMENTAL LINES OF RETZIUS
• Irregularly shaped.
• Concentric brown lines.
• Runs obliquely across enamel rods.
• Complete an arc in cuspal region but almost
parallel in cervical and middle third region.
49. PERIKYMATA
• Some incremental lines of Retzius fail to reach the
enamel surface.
• As a result a wave like groove is created on the
external surface.
• These are external manifestations of the line of
retzius.
• 30 in number near CEJ and 10 at incisal edge.
50. NEONATAL LINES
• Found in all deciduos teeth
and cusp of permanent 1st
molar.
• These are accentuated lines
of Retzius
• Formed due to some
disturbance of birth like
abrupt change in environment
before and after birth.
51. HUNTER SCHREGER BANDS
• SERIES OF ALTERNATING
LIGHT AND DARK BANDS
• START AT DEJ AND RUN
PERPENDICULAR TO STRIAE OF
RETZIUS
LONGITUDINAL GROUND SECTION IN OBLIQUE REFLECTED LIGHT OPTICAL
PHENOMENON
DIAZONES
PARAZONE
S
52. ENAMEL TUFTS
•Tasseled or unbraided
projections.
•Extends from DEJ into enamel
upto 1/3rd of its thickness.
•Follow direction of enamel
rods
•Origin controversial
53. ENAMEL LAMELLAE
• thin, leaf-like structures that extend from the
enamel surface toward the DEJ.
• They consist of organic material
HYPOMINERALISED.
• Lamellae may develop in planes of tension.
• Where rods cross such a plane, a short segment
of the rod may not fully calcify.
55. CLINICAL CONSIDERATION
• Dental lamellae may also be predisposing
locations for caries because they contain
much organic material
• Fluoride-containing mixtures such as
stannous fluoride pastes sodium fluoride
rinses acidulated phosphate fluoride are
used to alter the outer surface of the
enamel in such a manner that it becomes
resistant to decay.
56. ENAMEL SPINDLES
• odontoblastic processes of dentine
• cross DEJ and project in enamel
• thickened at end
• formed during formative stage of
amelogenesis
• hypersensitive to pain
59. PRISMLESS ENAMEL
• Structure less layer of enamel.
• • 20-70 Microns
• newly erupted
• permanent teeth Least – Cusp tips Most – Cervical
area
• crystallites are arranged uni-directionally, parallel to one
another with a relatively higher density.
• Prismless enamel in primary teeth
• In a primary same tooth at different areas it varies in
thickness (5–60micro m) , is the most commonly found
feature in the primary enamel.
60. ACID ETCHING IN PRIMARY
&PERMANENT TEETH
30sec
etch
30sec
wash
15sec
dry
Reference article by international academy of dental research. 2014
20sec
etch
30sec
wash
15sec
dry
P e r m a n e n t
p
r
i
m
a
r
y
62. AGE CHANGES IN ENAMEL
Attrition
Abrasion
Erosion
Abfraction
Caranza Textbook of Periodontology:10th Edition
63. ATTRITION
• Attrition The physiological wearing of tooth as a result of tooth
to tooth contact.
etiology
Abnormal
occlusion
Habits
Structural
defectsCaranza Textbook of Periodontology:10th Edition
64. PRESENT ON
OCCLUSAL OR
INCISAL
SURFACES
CALLED
FACETS
SHINY ,
SMOOTH AND
CURVIPLANAR
FACETS BEST
INDICATOR
WHY SHINY?
ENAMEL RODS
GET
FRACTURED &
ARE HIGHLY
REFLECTIVE TO
LIGHT
IN YOUNG
(ABNORMAL
ACTIVITY eg
BRUXISM) VS
OLDER ADULTS
(FUNCTIONAL
WEAR).
Caranza Textbook of Periodontology:10th Edition
65. Horizontal
facets
Forces directed
along vertical
axis of tooth
Periodontium
adapts
Angular
facets
Forces
directed
laterally
Risk of
damage to
periodontium
Angle of facets and periodontium
Caranza Textbook of Periodontology:10th Edition
66. ABRASION
• Abrasion Pathological wearing away of tooth substance
through abnormal mechanical process. ( OTHER THAN
MASTICATORY FORCES)
ETILOGY
OCCUPATIONAL
IMPROPER
BRUSHING
TECHNIQUE
HABITS
Caranza Textbook of Periodontology:10th Edition
67. Saucer shaped or wedge shaped indentations with
smooth and shiny surface.
Starts on exposed cementum surface instead of enamel
and spreads to dentin of root surface.
Horizontal brushing at right angles causes most severe
abrasion.
Abrasion can also take place in incisal edges due to
habits like holding objects.
Caranza Textbook of Periodontology:10th Edition
68. EROSION: THE DENTO-ALVEOLAR ABLATIONS
• Irreversible loss of tooth substance by
chemical process that does not involve
known bacterial action
• Wedge shaped depression in cervical area
generally facial surface of teeth.
• Long axis of eroded area perpendicular to
long axis of teeth.
• Starts on enamel . Early stages confined to
enamel , cementum and dentin are involved
later
Etiology
forceful frictional
actions between
oral mucosa
and dental hard
tissues
acidic fruits ,
GERD, low ph
of saliva e.t.c.
69.
70. ABFRACTION
• Acc to Grippo(1991) the pathologic loss of both enamel and dentin
caused by biomechanical loading forces.
• caused by clenching or grinding that causes tooth flexure resulting in
microfractures.
• "v-shaped" notches
• Gingival 3rd of the tooth.
Caranza Textbook of Periodontology:10th Edition
75. DEFINITION
• Defined as incomplete or defective formation of organic matrix of enamel.
• Occurs in the formative stage of amelogenesis.
• Basic types of enamel hypoplasia:
• 1. Hereditary enamel hypoplasia- both the deciduous and permanent dentitions are
involved and generally only the enamel is affected.
• 2.Environmental enamel hypoplasia. Both the dentition is involved or sometimes
even a single tooth and both enamel and dentin are affected.
76. FACTORS ASSOCIATED WITH
ENVIRONMENTAL TYPE
Nutritional
deficiency
exanthematous
disease
Congenital
syphilis
hypocalcemia
Birth injury,
prematurity, Rh
haemolytic
disease
Local infection
or trauma
Ingestion of
chemicals
idiopathic
77. NUTRITIONAL DEFICIENCY
• Due to deficiency of vitamin A, B & C.
• HORIZONTAL PITTING IS OBSERVED IN TEETH i.e.
THIS IS PITTING TYPE.
• Commonly seen in central and lateral incisors and
cuspids.
78. EXANTHEMOUS DISEASES
• Measles, chickenpox, scarlet fever.
• Due to elevated temperature of body ameloblast are affected.
• Involve those teeth formed in the first year after birth.
• The teeth most frequently involved are the central and lateral
incisors and first molar.
79. CONGENITAL SYPHILIS
• Involves the maxillary and mandibular permanent incisors and first molar.
• Anterior teeth -‘Hutchinsons teeth’ while the molars -‘Mulberry molars’.
• Due to the absence of the central tubercle or calcification center
Treponema
pallidum
Non pitting type
81. TRAUMATIC BIRTH INJURIES
• Neonatal line or ring is described by
Schour in 1936 present in first permanent
molars and deciduous teeth.
• In traumatic births the formation of enamel
may even cease at this time
• more common in prematurely born
children than in normal term infants
• Gastrointestinal disturbance or some
other illness in the mother may be
responsible
82. INGESTION OF CHEMICALS- FLUORIDE
Etiology:
ingestion of fluoride containing water during the time of tooth
formation may result in mottled enamel.
Mottling increases with increasing fluoride in water.
Water that contain in excess of 1PPM(part per million) fluoride
can affect the ameloblast during formative stage.
83. PATHOGENESIS
High fluoride
Matrix formation stage
Diminished matrix
production
Change in ion
transport
Diminished
withdrawal of
protein.
Maturative
stage
Diminished
withdrawal of water
84. LOCAL INFECTION OR TRAUMA
• Caused by local infection or trauma and is
called “Turner’s Hypoplasia” and the tooth
is called as Turner’s tooth.
• Site- Maxillary incisors & permanent
premolars Appearance- mild brownish
discoloration of enamel to severe pitting and
irregularity of crown.
Turners hypoplasia
86. Deciduous tooth
becomes carious when
crown of successor
teeth is being formed.
Bacterial infection
goes to periapical
region of
deciduous tooth.
Disturbs the
ameloblastic layer of
permanent teeth.
Results in
hypoplastic
crown.
Trauma to deciduoud
teeth , teeth driven in
alveolus,
infection
trauma
90. TREATMENT
• Cosmetic reasons it has become the practice to bleach
the affected teeth with an agent such as hydrogen
peroxide.
• Procedure must be carried out periodically since the
teeth continue to stain.
91. AMELOGENESIS IMPERFECTA
• Amelogenesis imperfecta is a group of clinically and
genetically heterogeneous disorders that affect the
development of enamel and result in abnormalities of the
amount, composition, and/or structure of enamel.
• These disorders are caused by mutations in a variety of
genes that are important for enamel formation.
Purely
ectodermal
disorder.
Dentin and
pulp are
normal.
99. HYPOCALCIFICATION TYPE
• Stage effected is mineralization.
Teeth of normal thickness but very soft can be easily removed by an explorer.
Change in shape of tooth takes place due to persistent fractgures of soft enamel.
C/F
Cheesy in
consistency
!
100. C/F
H/F
Calcification is altered so enamel now
has the same radiodensity as dentin
making it very difficult to distinguish
the two.
Defect In mineral deposition can be
attributed.
101. HYPOMATURATION TYPE
• Stage effected is maturation
Enamel is of normal thickness but can be pierced by an explorer under firm
pressure.
C/F
H/F
R/F
Alteration in enamel rod and rod sheath structure.
Same as hypocalcification that is radiodensity is
SAME AS DENTIN
103. GENETIC FACTORS
• Amelogenesis imperfecta have shown defective gene linked
to the locus DXS85 at Xp22. • This is also the location for
amelogenin.
108. NEWER ADVANCES
• MOLAR INCISOR HYPOMINERALISATION.
• Defined as “systemic hypomineralization” that affects one or more
permanent first molars with or without permanent incisor involvement.
• It is a qualitative defect of the enamel.
• Other names hypomineralized permanent first molars (PFMs) /
idiopathic enamel hypomineralization / nonfluoride hypomineralization /
dysmineralized PFMs.
MIH
109. PROBLEMS IN MIH
• Teeth with MIH have porous enamel that easily breaks under masticatory forces.
• Fracture of enamel exposed dentinal tubules high susceptibility towards degradation
hence CARIES
• Intense dentinal sensitivity
• The children affected with MIH are at a risk of developing behavior management
problems and dental fear because of the difficulties in achieving adequate anesthesia.
110. CHARACTERISTICS OF MIH
• The characteristic feature of MIH is the clear demarcation between
the affected and sound enamel. There is asymmetry of defects
present in the molars and incisors where one molar or incisor can
be severely affected while the contralateral tooth may be clinically
sound or have only minor defects. Rapid dental wear, loss of
enamel, inclination to caries, dentin hypersensitivity, poor esthetics,
anxiety, and tooth loss can occur in the long run.
112. EAPD CRITERIA FOR MIH DIAGNOSIS.
• All the data were collected and scored using the European Academy of Pediatric
Dentistry (EAPD) criteria for MIH.(2003)
• 0 – Normal
• 1 – Demarcated opacity
• 2 – Posteruptive enamel breakdown
• 3 – Atypical restorations
• 4 – Extracted molar due to MIH
• 5 – Unerupted molar due to MIH.
113. TREATMENT OF MIH
• Restorative treatments for these hypomineralized teeth present with ten times more
requirement than teeth without this condition. It ranges from prophylactic strategies to
high complexity procedures.
• Restorative treatments for these teeth are challenging for both the patient and the
dentist due to the subclinical inflammation of pulpal cells and the altered porous
enamel structure that makes bonding risky leading to defective and frequent loss of
fillings and frequent retreatments which are painful because of anesthetizing
difficulties.
114. CHRONOLOGICAL HYPOPLASIA
• Chronological hypoplasia is differentiated from other forms of hypoplasia due to its
characteristic presentation (multiple, symmetrical, chronological pattern).
• Chronological hypoplasias are seen at the time tooth erupts into the oral cavity leading
to several problems like aesthetic problems, tooth sensitivity, caries and early pulpal
involvement.
115. TAKE HOME MESSAGE
• Knowledge of the magnitude of MIH is desirable as it is vulnerable for consequences such as
rapid caries development, early enamel loss, and sensitivity.
• Failure in treatment occurs due to lack of basic
knowledge.
• Proper understanding of the basics like ENAMEL can
lead to proper DIAGNOSIS hence proper
TREATMENT.
116. REFERENCES
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