Developmental Defects of Teeth
developmental defects of teeth with recent genetic concepts
INTRODUCTION: Disorders of development of teeth may be prenatal or postnatal in origin and may be inherited or acquired. Their recognition and evaluation requires a thorough knowledge and evaluation of the normal chronology of the human dentition and of the normal development and structure of the teeth. Disorders of development of teeth of teeth may be due to abnormalities in the differentiation of the dental lamina and the tooth germs, causing anomalies in the number, size and form of teeth (abnormalities of morphodifferentiation) or to abnormalities in the formation of the dental hard tissues resulting in disturbances in tooth structure (abnormalities of histodifferentiation). Abnormalities of histodifferentiation occur at a later stage in development than abnormalities of morphodifferentiation; in some disorders both stages are abnormal.
Histophysiology of tooth development: A number of physiologic growth processes participate in the progressive development of the teeth.
These are – 1. Initiation The dental lamina and associated tooth buds represent those parts of the oral epithelium that have the potential for tooth development. Different teeth are initiated at different times. Initiation induction requires ectomesenchymal epithelial interaction. A lack of initiation results in the absence of either a single or multiple teeth or complete lack of teeth. Abnormal initiation may result in the development of single or multiple supernumerary teeth. 2. Proliferation Enhanced proliferative activity after initiation results successively in the bud, cap and bell stages of the odontogenic organ. Proliferative growth causes regular changes in the size and proportions of the growing tooth germ. A disturbance has entirely different effects according to the time of occurrence and the stage of development that it affects. Tooth anomalies may include
INTRODUCTION: Disorders of development of teeth may be prenatal or postnatal in origin and may be inherited or acquired. Their recognition and evaluation requires a thorough knowledge and evaluation of the normal chronology of the human dentition and of the normal development and structure of the teeth. Disorders of development of teeth of teeth may be due to abnormalities in the differentiation of the dental lamina and the tooth germs, causing anomalies in the number, size and form of teeth (abnormalities of morphodifferentiation) or to abnormalities in the formation of the dental hard tissues resulting in disturbances in tooth structure (abnormalities of histodifferentiation). Abnormalities of histodifferentiation occur at a later stage in development than abnormalities of morphodifferentiation; in some disorders both stages are abnormal.
Histophysiology of tooth development: A number of physiologic growth processes participate in the progressive development of the teeth.
These are – 1. Initiation The dental lamina and associated tooth buds represent those parts of the oral epithelium that have the potential for tooth development. Different teeth are initiated at different times. Initiation induction requires ectomesenchymal epithelial interaction. A lack of initiation results in the absence of either a single or multiple teeth or complete lack of teeth. Abnormal initiation may result in the development of single or multiple supernumerary teeth. 2. Proliferation Enhanced proliferative activity after initiation results successively in the bud, cap and bell stages of the odontogenic organ. Proliferative growth causes regular changes in the size and proportions of the growing tooth germ. A disturbance has entirely different effects according to the time of occurrence and the stage of development that it affects. Tooth anomalies may include