Method: A total of 57 patients between 8 and 36 years of age (41 females and 16 males) participated in this study. The lateral cephalometric measurements included angles SNA, SNB ANB and MP/PP to evaluate maxillary and mandible positions in the sagittal and vertical dimensions; ratio Lower face height to total face height ratio LFH/TFH; lengths of mandible CO-GN, and maxilla ANS-PNS. All subjects underwent acoustic analysis using VISI-PITCH IV including Fundamental frequency (F0) and habitual frequency.
Result: The means for SNA, SNB, ANB were 80.7°+3.2°, 77.4°+3.6°, and 3.3°+2.6° respectively. The mean for the MP/PP was 25.9°±6.2°, and LFH/TFH was 54.53% +2.83. F0 and Habitual frequency averaged 220.75 Hz + 40.01 Hz and 216.99 Hz + 43.9 Hz respectively. The mean length of the mandible and maxilla were 104.28 mm+7.94 mm and 50.29 mm+3.94 mm respectively. Weak correlations existed between mandibular and maxillary positions in the sagittal and vertical dimensions. There was a moderate negative correlation between the length of the mandible (CO-GN), F0 and habitual frequency (p<0.05, r=-0.53 and p<0.001, r=-0.58 respectively). Similarly, a moderate negative correlation existed between the length of the maxilla (ANS-PNS), F0 and habitual frequency (p=0.001, r=-0.47, and p<0.05, r=-0.52 respectively). Correlation between mandibular length and F0 (r=-0.63) and habitual pitch (r=-0.64) increased significantly in the post-pubertal group (age > 16 years; n =13).
Conclusion:
Jaws positions in the sagittal and vertical dimensions did not correlate with F0 and habitual pitch, but an increased association existed between jaws length and voice parameters, stronger in post pubertal subjects. A larger sample of adult subjects is needed to confirm the results.