Occlusion in 47,XXY (Klinefelter syndrome) men

Differences in the Eruption Angle of Palatally Displaced Canines in Klinefelter Syndrome: a Retrospective Study on Panoramic Radiographs

Objective

To investigate the eruption angle of maxillary canine in patients with Klinefelter syndrome (KS) in which high prevalence of palatally displaced canine anomaly (PDC) has been found by clinical assessment.

Subjects and Methods

The sample consisted of 37 KS males aged 20-34 years (mean 27 years) and the control group which consisted of 78 healthy males aged 20-27 years (mean 23 years). A pioneer method was used to measure the eruption angle. It was based on determining the topographic construction of mandibular gonion line called GO-GO method on panoramic radiograph.

Results

The mean of eruption angle was increased for 10.58° in the right side and 9.69 ° in left side in patients with KS compared to those in the control group. The difference of mesioangular inclination of palatally displaced canines in Klinefelter patients was statistically significant (p< 0.01). When eruption angle in the control group was compared to Klinefelter patients, the statistical difference was confirmed for respective sides (P <0.01 for both).

Conclusions

The difference between eruption angle values in KS patients as well as in those belonging to the control group seemed to identify a developmental disturbance, thus confirming the fact that an extra X chromosome has an influence. The GO-GO method might be used for males when it is difficult to define occlusal planes, or for comparison. If this method is used, the eruption angular values should not exceed 56.74°.

Abnormal enamel and pulp dimensions in familial dysautonomia

In familial dysautonomia (FD), a hereditary autonomic and sensory neuropathy, somatic growth is impaired. This study was conducted to explore the possibility that tooth dimensions are altered as a consequence of neural crest dysfunction known to be present in FD. Enamel, dentin, pulp, and tooth size measurements of mandibular primary and permanent molars from FD patients were compared with those of healthy controls. It was found that although tooth size in the FD patients was smaller than normal, the enamel was thicker on the occlusal table, while the pulp chamber was smaller and disproportional to tooth size. Our results suggest distorted tooth dimensions rather than a generalized growth arrest as observed in other hereditary syndromes, such as Down's or Crouzon.

A study in 47,XYY men of the expression of sex-chromosome anomalies in dental occlusion

Occlusal traits were determined for 47,XYY men and compared with previous determinations of occlusal morphology in other sex-chromosome anomalies and in normal women and men. The 47,XYY men, like 47,XXY men, tended to have a mesial molar occlusion and a mandibular overjet more often than did other groups, while 45,X women (Turner patients) clearly had the highest frequency of distal occlusion and large overjet. The 47,XXY men had the highest frequency of most occlusal anomalies. As a whole, these and earlier findings suggest that the number of X or Y chromosomes is associated negatively with distal occlusion and lateral crossbite, whereas a positive association was found with mesial molar occlusion and scissors bite.