Clinical applicability of variations in arch dimensions and arch forms among various vertical facial patterns.

OBJECTIVE To compare dental arch dimensions and arch forms in various vertical facial patterns. STUDY DESIGN Cross-sectional comparative study. PLACE AND DURATION OF STUDY The Aga Khan University Hospital, Karachi, from June 2007 to May 2008. METHODOLOGY Cases of age ranging 13-30 years were reviewed having full complement of teeth (upto second permanent molars) with less than 7 mm crowding. Exclusion criteria included presence of dental anomalies, previous dentoalveolar surgery, trauma or orthodontic treatment and craniofacial syndromes. One hundred cases including 40 normodivergent, 30 hypodivergent and 30 hyperdivergent facial patterns were selected. Occlusograms were made and various arch dimensions were measured. Arch forms were calculated according to ratios of three sagittal to three transverse dimensions. RESULTS The mean age of the sample was 21 years and 5 months. Significant differences in arch dimensions were found only in maxillary total arch length (p=0.03) and mandibular posterior intermolar width (p=0.04). Wide lower arches were predominant in all face types. Wide upper arches were predominant only in hypo- and hyperdivergent subjects. CONCLUSION Statistically significant difference in arch dimensions was found only in maxillary total arch length and mandibular posterior intermolar width. A non-linear relationship was found between arch length and arch width. Wide lower arches were predominant in all face types whereas wide upper arches were predominant in hypo- and hyperdivergent subjects.