An association between sella turcica bridging and dental transposition.

The aim of the present study was to determine any association between tooth transposition and bridging of the sella turcica, given the evidence of common embryonic origins associated with these structures and a genetic basis underlying these two conditions. Clinical records of subjects demonstrating dental transposition and normal controls were collected from several hospital orthodontic departments and specialist orthodontic practices. All cases and controls were documented with good quality lateral cephalometric radiographs and dental panoramic tomograms (DPTs). The study sample consisted of 21 Caucasian subjects (7 males and 14 females; mean age 14.5 years; SD 2.2 years), demonstrating either maxillary or mandibular dental transposition. The control group, matched for age and gender to the study sample, comprised 70 Caucasians (31 males and 39 females; mean age 13.8 years; SD 1.8 years) without dental anomalies randomly selected from subjects referred for orthodontic treatment within the same departments. The extent of sella turcica bridging was quantified from each profile radiograph using comparative measurement of length and diameter. Sella turcica bridging was found more frequently in subjects diagnosed with dental transposition than in the controls, with the difference being statistically significant [chi-square=7.4; degrees of freedom (df)=2; P=0.025; Fisher's exact test; P=0.042]. The increased frequency of complete and partial bridging of the sella turcica in subjects with dental transposition provides further evidence of a genetic basis to this condition. As calcification and bridging of this region can present during early childhood, it may act as a useful diagnostic predictor of susceptibility to local dental problems.