Developmental Disturbances of Teeth
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True generalized microdontia involves all teeth being smaller than normal and is seen in cases of pituitary dwarfism. Macrodontia refers to teeth being larger than normal. Geminated teeth arise from an attempt at division of a single tooth germ. Taurodontism is the enlargement of the tooth body and pulp chamber with displacement of the pulpal floor. Amelogenesis imperfecta represents hereditary defects of enamel formation. Dentinogenesis imperfecta affects dentin formation resulting in teeth that are gray to yellowish-brown.
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Developmental Disturbances of Teeth
- 1. DEVELOPMENTAL DISTURBANCES OF TEETH Done by: AMRITHA JAMES CRRI
- 2. Developmental Disturbances In Size of Teeth
- 3. Microdontia • This term is used to describe teeth which are smaller than normal. • Three types of microdontia are recognized: True generalized microdontia Relative generalized microdontia Microdontia involving a single tooth
- 4. – True generalized microdontia All teeth are smaller than normal. Seen in cases of pituitary dwarfism. Teeth are well formed – Relative generalized microdontia Normal or slightly smaller than normal teeth are present in jaws that are larger than normal. – Microdontia involving a single tooth Most commonly affected teeth are maxillary lateral incisor and third molar. The most common form of localised microdontia affects the lateral incisor, and is called as peg lateral. In peg laterals the mesial and distal surfaces converge or taper incisally, frming a peg shape. The root of such tooth is shorter than usual.
- 5. Macrodontia • Teeth are larger than normal. • Three types of macrodontia are recognized: True generalized Marcrodontia Relative generalized Marcrodontia Marcrodontia involving a single tooth
- 6. – True generalized macrodontia All teeth are larger than normal. Seen in cases of pituitary gigantism Extremely rare – Relative generalized macrodontia Normal or slightly larger than normal teeth are present in small jaws. – Macrodontia involving a single tooth Uncommon
- 7. Developmental Disturbances In Shape of Teeth
- 8. Gemination • Geminated teeth are anomalies which arise from an attempt at division of single tooth germ by an invagination, with resultant incomplete formation of two teeth. • CLINICAL FEATURES Seen in both primary and permanent dentitions. Has higher frequency in the anterior and maxillary regions. Incisors and canines are most commonly affected. Teeth demonstrate a pronounced labial or lingual groove.
- 9. • CLINCAL SIGNIFICANCE Gemination can result in crowding and delayed or ectopic eruption of the underlying permanent teeth and hence have to be extracted in certain cases. The labial or lingual groove are prone to develop caries and hence in such cases fissure sealant should be used.
- 10. Fusion • Fused teeth arise through union of two normally separated tooth germ. • CLINICAL FEATURES Fusion may be complete or incomplete. The tooth may have separate or fused root canals. Teeth demonstrate a pronounced labial or lingual groove Affects both primary and permanent teeth. Most frequently occurs in the mandible. • CLINICAL SIGNIFICANCE Fusion Results in spacing The labial and lingual grooves are prone to develop caries.
- 11. Concrescence • Teeth are united by the cementum only. • It arises as a result of traumatic injury or crowding of teeth with resorption of the interdental bone so that the two teeth are in approximate contact and become fused by deposition of cementum. • CLINICAL FEATURES – Most commonly seen in the posterior and maxillary regions. – It can occur before or after the teeth have erupted. • CLINICAL SIGNIFICANCE – No therapy is usually required unless the union interferes with eruption, then surgical removal may be warranted.
- 12. Dilaceration • Dilaceration refers to an angulation or a sharp bent in the root or crown of a tooth. • It arises after an injury that displaces the calcified portion of the tooth germ and the reminder of the tooth is formed at an abnormal angle. • CLINICAL FEATURES – Most commonly affected teeth are the mandibular third molars followed by the maxillary second premolars and mandibular second molars. – Failure of eruption is often seen . – Those that achieve eruption follow an altered path.
- 13. • CLINICAL SIGNIFICANCE Altered deciduous teeth often demonstrate inappropriate resorption and results in delayed eruption of permanent teeth. Extraction is indicated in such conditions. Teeth with abnormal eruption may be exposed and orthodontically moved into proper position. Dilacerated roots concentrate stress in the affected tooth if used as abutment. Splinting of the dilacerated tooth to an adjacent tooth over comes the stress related problems.
- 14. Talon Cusp • Talon Cusp is an anomalous structure resembling an eagles talon. • CLINICAL FEATURES Talon cusp projects lingually from the cingulum areas of maxillary or mandibular permanent incisor. The cusp blends smoothly with the tooth . A deep developmental groove is present where the cusp blends with the sloping lingual tooth surface. Composed of normal enamel, dentin and contains a horn of pulp tissue. Most commonly seen in association with Rubinstein-Taybi syndrome.
- 15. • CLINICAL SIGNIFICANCE Talon cusp on maxillary teeth interfere with occlusion and should be removed The developmental groove may be prone to caries. Removal with out loss of vitality may be accomplish through periodic grinding of the cusp resulting in tertiary dentine deposition and pulpal recession.
- 16. Dens Invaginatus • Dens Invaginatus is a deep surface invagination of the crown or root that is lined by enamel. • TYPES Coronal radicular • CLINICAL FEATURES Most commonly affected teeth are permanent lateral incisors. Depth of invagination varies from a slight enlargement of the cingulum pit to a deep infolding that extends to the apex. Invagination may be large and resemble a tooth with in a tooth and hence the term ‘Dens In Dente’
- 17. Three types of coronal invagination is seen: Type I - Invagination is confined to the crown Type II – Invagination extents below the cementoenamel junction and ends In a blind sac that may or may not communicate with the adjacent pulp. Type III – Invagination extents through the root and perforates in the apical or lateral radicular area without communication with the pulp. Radicular Dens invaginatus arises secondary to proliferation of hertwig’s root sheath with the formation of strip of enamel that extends along the surface of the root.
- 18. • CLINICAL SIGNIFICANCE In type I Invaginations the opening of the invagination should be restored after eruption to prevent caries. In larger invagination the content of the lumen and any carious dentin must be removed and calcium hydroxide base must be placed to treat micro communications with the pulp. In type III endodontic therapy is required.
- 19. Dens Evaginatus • Dens Evaginatus appears clinically as an accessory cusp or globule of enamel on the occlusal surface between buccal and lingual cusp of pre molars. • Occurs as a result of proliferation and evagination of an area of inner enamel epithelium and odontogenic mesenchyme into the enamel organ during tooth development. • CLINICAL SIGNIFICANCE May interfere with occlusion and should be removed Removal with out loss of vitality may be accomplish through periodic grinding of the cusp
- 20. Taurodontism • It is the enlargement of the body and pulp chamber of a multirooted teeth with apical displacement of the pulpal floor. • RADIOGRAPHIC FEATURES Affected teeth tend to be rectangular. Increase in apicoocclusal height Bifurcation lies close to the apex No cervical constriction • The degree of taurodontism has been classified into: Mild (hypotaurodontism) Moderate(mesotaurodontism) severe(hypertaurodontism) • No specific therapy is required
- 21. Enamel Pearls • They are ectopic collections of enamel. • These are hemispherical structures consisting of enamel or may contain dentin and pulp. • Enamel pearls arise from localized bulging of the odontoblastic layer which provides prolonged contact with hertwig’s root sheath triggering the induction of enamel formation • CLINICAL FEATURES Most frequently found on the roots of maxillary molar. • RADIOGRAPHIC FEATURES They appear as well defined, radiopaque nodules along the root surface. Mature internal enamel pearls appear as areas of radio density extending from the dentinoenamel junction into the coronal dentin.
- 22. • CLINICAL SIGNIFICANCE Enamel pearls are areas of weak periodontal attachment. Hence meticulous oral hygiene should be maintain.
- 23. CERVICAL ENAMEL EXTENSIONS • They occur along the surface of the root. • These extensions represents a dipping of the enamel from the CEJ towards the bifurcation of the molar teeth. • Mandibular molars are more commonly affected. • CLINICAL SIGNIFICANCE Cervical enamel extensions are associated with weak periodontal attachments. These have been associated with the formation of buccal bifurcation cyst.
- 24. Hypercementosis • Hypercementosis is the non neoplastic deposition of cementum that is continuous with the normal radicular cementum. • CLINICAL FEATURES Mandibular molars are more frequently affected. Frequency increases with age. • RADIOGRAPHIC FEATURES There is thickening or blunting of the root • CLINICAL SIGNIFICANCE Sectioning of the tooth may be necessary during removal.
- 25. Supernumerary Roots • Increase in the number of roots. • CLINICAL FEATURES Both primary and permanent teeth may be affected. Most commonly affected teeth are the permanent molars. The supernumerary root is usually divergent and easily seen on radiograph. • CLINICAL SIGNIFICANCE The accessory roots have to be detected before endodontic therapy and exodontia.
- 26. Developmental Disturbances In Number of Teeth
- 27. Anodontia • Anodontia refers to the congenital absence of teeth. • Types: Total anodontia- all the teeth are missing False anodontia- occurs as a result of extraction of all teeth. Partial anodontia- one or more teeth are missing
- 28. Supernumerary Teeth • A supernumerary tooth may closely resemble the teeth of a group to which it belongs or may show little resemblance. • Males are affected twice as frequently as females. • A supernumerary teeth in the maxillary anterior incisor region is called mesiodens. • An accessory fourth molar is called a distomolar. • A posterior supernumerary tooth situated lingually or bucally is called a paramolar. • Classification: Conical Tuberculate Supplemental Odontome
- 29. • Conical Peg shaped Usually presents as a mesiodens • Tuberculate Has one or more cusps Barrel shaped Paired and located palatal to central incisors • Supplemental Have normal shape and size Most common supplemental tooth is the permanent lateral incisor. • Odontome Of two types- complex and compound
- 30. Developmental Disturbances In Structure of Teeth
- 31. Amelogenesis imperfecta • Amelogenesis imperfect represents a group of hereditary defects of enamel. • It is caused by alterations of genes involved in the process of formation and maturation of enamel • It may be differentiated into three main groups: Hypoplastic Hypomature Hypocalcified
- 33. • RADIOGRAPHIC FEATURES Abnormally shaped tooth Enamel may be totally absent or may appear as a thin layer over the cusps and interproximal surfaces. Calcification of enamel may be affected such that it appears to have the same radiodensity of dentin. • HISTOLOGICAL FEATURES Hypoplastic type- defect in matrix formation Hypocalcified type- defect of matrix structure and of mineral deposition hypomaturation type- alterartions in enamel rods and sheaths. • TREATMENT Prosthodontic reconstuction
- 34. Dentinogenesis Imperfecta • Dentinogenesis imperfecta is an autosomal dominant condition affecting both deciduous and permanent teeth. • Affected teeth are gray to yellowish brown and have broad crowns with constriction of the cervical area resulting in a tulip shape. • TYPES Dentinogenesis imperfecta I Dentinogenesis imperfecta II
- 35. DENTINOGENESIS IMPERFECTA I Also known as opalescent dentin. Caused by mutation of DSPP gene. The teeth are blue gray or amber brown and opalescent. On radiograph the teeth have bulbous crowns, roots that are narrower than normal, and pulp chambers and root canals that are smaller than normal or obliterated. The enamel may split readily from the dentin when subjected to occlusal stress. DENTINOGENESIS IMPERFECTA II The crowns of the deciduous and permanent teeth wear rapidly after eruption and multiple pulp exposure may occur. The dentin is amber and smooth. Radiograph of deciduous teeth shows large pulp chambers and root canals which reduces with age. The pulp spaces of the permanent teeth may be completely obliterated. Shell teeth appearance
- 36. • CHEMICALAND PHYSICAL FEATURES Inorganic content of dentin is reduced. Water content is greatly increased. Micro hardness of the dentin closely approximates cementum resulting in rapid attrition. • TREATMENT Cast metal crowns on posterior teeth and jacket crowns on anterior teeth can be used for restoration.
- 37. Dentin Dysplasia • Dentin Dysplasia is an autosomal dominant disturbance in dentin formation characterized by normal enamel but atypical dentin formation with abnormal pulp morphology. • TYPES Radicular Dentin Dysplasia Coronal Dentin Dysplasia • CLINICAL FEATURES Type I Both dentitions are affected Slight amber translucency Teeth characteristically exhibit extreme mobility and are exfoliated prematurely or after minor trauma as a result of abnormally short roots. Type II Both dentitions are affected. Deciduous teeth are yellow, brown or bluish gray opalescent in appearance. Clinical appearance of permanent dentition is normal.
- 38. • RADIOGRAPHIC FEATURES – Type I Roots are short, blunt , conical or malformed. In deciduous teeth pulp chambers and root canals are completely obliterated. In permanent dentition a crescent shaped pulpal remnant is seen. Periapical radiolucencies may be seen. – Type II In deciduous teeth pulp chambers and root canals are completely obliterated. In permanent teeth abnormally large pulp chambers are seen (Thistle tube in shape) with areas of radiopaque foci. • TREATMENT No treatment
- 39. REGIONAL ODONTODYSPLASIA • Also known as ghost teeth. • Maxillary teeth ate involved more frequently. • CLINICAL FEATURES There is a delay or total failure of eruption. The shape is irregular. There is defect in mineralization • RADIOGRAPHIC FEATURES Marked reduction in radiodensity. Ghost appearance Both enamel and dentin appear very thin. Pulp chamber is exceedingly large.
- 40. • HISTOLOGICAL FEATURES Marked reduction in the amount of dentin. Widening of predentin layer. Presence of large areas of interglobular dentin. Irregular tubular pattern of dentin. • TREATMENT Extraction with restoration by prosthetic appliance is indicated.
- 41. Developmental Disturbances Of Growth (Eruption) Of Teeth
- 42. PREMATURE ERUPTION • Deciduous teeth that have erupted into the oral cavity are occasionally seen in infants. • When teeth are present at birth it is known as natal teeth. • Teeth which erupt prematurely in the first 30 days of life is known as neonatal teeth. • CLINICAL FEATURES The teeth are usually well formed and normal. Most commonly seen premature teeth are mandibular central incisor.
- 43. EMBEDDED TEETH • Embedded Teeth are individual teeth which are unerupted due to lack of eruptive force.
- 44. IMPACTED TEETH • Impacted teeth are those prevented from erupting by some physical barrier in the eruption path. • Most commonly affected teeth are mandibular third molar and maxillary cuspids. • Impaction may be mesioangular, distoangular, vertical or horizondal
- 45. ANKYLOSED TEETH • Also known as submerged teeth. • Mandibular second molars are most commonly affected. • There is union of cementum with bone. • This prevents exfoliation and subsequent replacement by permanent teeth. • The ankylosed teeth appears submerged below the level of occlusion. • The affected teeth lack mobility even though root resorption is far advance. • Percussion results in solid sound. • Radiograpically there is absence of periodontal ligament.