Dentoalveolar bone height in Class I adults with different vertical patterns: A cross-sectional study

Background

Facial divergence during growth and development affects both the anterior and posterior alveolar bone dimensions in the maxilla and mandible, and the dentoalveolar compensation mechanism in severe vertical skeletal discrepancies remains unclear.

Aims

To evaluate the: (1) difference in dentoalveolar heights among subjects with different vertical facial patterns; (2) association between the dentoalveolar bone height and other cephalometric variables; (3) effect of sex on dentoalveolar height measurements.

Material and methods

Non-growing subjects with skeletal Class I (0° < ANB < 4°), Class I canine and molar relationship and complete fully erupted dentition were included in the study. Cephalometric measurements were taken on lateral cephalograms and patients were stratified into hyperdivergent, hypodivergent, and normodivergent groups based on MP/SN angle. A two-way analysis of variance (ANOVA) was used to compare cephalometric measurements between the divergence and sex groups.

Results

Measurements on a total of 204 patients (81 males, 123 females) were analysed. At the level of the incisor and premolar regions, both dentoalveolar and alveolar bone heights were significantly larger in hyperdivergent group when compared to hypodivergent group, whereas at the level of the molar region, no difference was found among groups. Moderate to strong correlations were found between dentoalveolar bone and vertical skeletal measurements.

Conclusions

In the maxilla and mandible, the dentoalveolar compensation mechanism in skeletal Class I subjects results in an increased vertical height in the anterior dentoalveolar segment in hyperdivergent subjects and a reduced one in hypodivergent subjects.