Evaluation of intermaxillary tooth size ratios and discrepancies according to craniofacial growth pattern

Proportionality of the maxillary and mandibular teeth is a key factor for an ideal intercuspation at the end of orthodontic treatment.

Aim
The aim of this study was to compare the anterior tooth size ratios and the prevalence of discrepancies among different craniofacial growth patterns in an orthodontic population.

Material and methods
The retrospective study examined cephalograms and pre-orthodontic study models of 714 patients with a mean age of 15.36 ± 2.12 years. Patients were divided into 9 subgroups according to skeletal sagittal malocclusions and vertical growth patterns. Mesiodistal dimensions of the anterior teeth were measured and the intermaxillary ratio and tooth size malocclusions were determined.

Results
In total, Class III malocclusions had a higher Bolton ratio and prevalence of discrepancies compared to other malocclusions (p<0.01). No significant difference was found between different vertical subgroups of the same sagittal malocclusion with regard to Bolton ratio and the prevalence of discrepancies (p>0.05). No significant difference was found among hypodivergent sagittal Class I, II and III malocclusions with vertical growth patterns (p>0.05), while a significant difference was detected between normodivergent and hyperdivergent subgroups with regard to Bolton ratios (p<0.05). The prevalence of discrepancies greater than 2 SD was significantly higher in individuals with normodivergent and hyperdivergent Class III malocclusions compared to other individuals (p<0.05).

Conclusion
The vertical growth pattern affects Bolton ratio and the prevalence of discrepancies when combined with sagittal malocclusions.