Vertical characteristics of posterior teeth in untreated malocclusions

Abstract

ObjectiveUnderstanding the influence of tooth eruption on skeletal growth patterns can contribute to development of timely and effective orthodontic treatment protocols. In this retrospective cross-sectional study, our objective was to use a previously published cephalometric method to measure the maxillary and mandibular molar and premolar dentoalveolar heights from an untreated sample of Class II and Class III subjects and compare them to untreated Class I normodivergent. Materials and MethodsA total of 218 subjects with full permanent dentition that met the defined inclusion, exclusion, and grouping criteria were analyzed. The sample of 13- to 56-year-old subjects was diverse in ethnic backgrounds and representative of an urban practice setting. Using cephalometric grouping criteria, subjects were assigned to one of five groups: Class I normodivergent (control), Class II or Class III hyperdivergent or hypodivergent. Cephalometric images were traced and data were analyzed using independent t-tests, one-way analysis of variance, and Bonferroni post hoc tests (P < 0.05). ResultsThe study showed strong trends of short maxillary dentoalveolar heights in Class II hypodivergent subjects and short mandibular dentoalveolar heights in Class III hyperdivergent subjects. Statistically significant differences ranged from 1.11 mm to 4.55 mm. The results of this study indicate gender dimorphism. ConclusionsThis study suggests that posterior dentoalveolar characteristics differ among the established malocclusions. There is likely an interplay between tooth eruption and vertical growth of the jaws. One factor can influence the severity of another, as the dentition and skeleton develop simultaneously. Clinical treatment approaches to minimize divergence from the normal skeletal pattern can be established for growing patients.