Development alterations in the shape of teethPresentation Transcript
Developmentalterations in theshape of teeth
Development alterations in theshape of teeth• Definition:• Tooth size is variable among different races and between the sexes. The presence of unusually small teeth is termed microdontia; the presence of teeth larger than average is termed macrodontia. Although hereditary is the major factor, both genetic and environmental influences affect the size of developing teeth. The deciduous dentition appears to be affected more by maternal intrauterine influences; the permanent teeth seem to be more affected by environment.
Development alterations in theshape of teeth• Clinical features:• Although the size of teeth is variable, there is usually symmetry of the two sides of the jaws. In spite of this, when significant size variation is present, the entire dentition rarely is affected. Typically, only a few teeth are altered significantly in size. Differences in tooth size cannot be considered in isolation. Microdontia is associated strongly with hypodontia; macrodontia often is seen in association with hyperdontia. Females demonstrate a higher frequency a microdontia and hypodontia; males have a greater prevalence of macrodontia and hyperdontia.
Development alterations in theshape of teeth• Microdontia. The term microdontia should be applied only when the teeth are physically smaller than usual. Normal- sized teeth may appear small when widely spaced within jaws that are larger than normal. This appearance has been historically termed relative microdontia, but it represent macrognathia. Diffuse true microdontia is uncommon but may occur as an isolated finding in Down syndrome. In pituitary dwarfism, and in association with a small number of rare hereditary disorder that exhibit multiple abnormalities of the dentition.
Development alterations in theshape of teeth• Isolated microdontia within an otherwise normal dentition is not uncommon. The maxillary lateral is affected most frequently and typically appears as a peg-shaped crown overlying a root that often of normal length. The mesiodistal diameter is reduced, and the proximal surfaces coverage toward the incisal edge. The reported prevalence varies from 0.8% to 8.4% of the population, and the alteration appears to be autosomal dominant with incomplete penetrance. In addition, isolated microdontia often affects third molars are among the most frequent teeth to be congenitally missing. When a peg-shaped tooth is present, the remaining permanent teeth often exhibit a slightly smaller mesiodistal size.
Development alterations in theshape of teeth• Macrodontia. Analogous to microdontia, the term macrodontia should be applied only when teeth are physically larger than usual and should not include normal-sized teeth crowded within a small jaw. In addition, the term macrodontia should not be used to describe teeth that have been altered by fusion or gemination. Diffuse involvement is rare, and typically only a few teeth are abnormally large. Diffuse macrodontia has been noted in association with pituitary gigantism and pineal hyperplasia with hyperinsulinism. Macrodontia with unilateral premature eruption is not rare in hemifacial hyperplasia. Authors have postulated that the unilateral bone growth resulting from this condition may also affect developing teeth on the altered side.
Development alterations in theshape of teeth• Treatment and Prognosis• Treatment of the dentition is not necessary unless desired for aesthetic considerations. Maxillary peg laterals often are restored to full size by porcelain crown.