Skeletal components of class III malocclusions and compensation mechanisms

The aim of this retrospective study was to assess the skeletal characteristics of sagittal maxillary and mandibular discrepancies resulting in class III malocclusions and compensation mechanisms in one Caucasian European population (Croatian). The study sample included 107 patients (63 females and 44 males), aged between 11 and 18 years of age (mean age 14.6 +/- 2.2), with a class III malocclusion. Forty-three angular and linear measurements were assessed from the pre-treatment lateral cephalographs of each subject. ANOVA, Tukey post hoc and t-test were used for statistical analysis. The most common differential skeletal type was mandibular prognathism with a normal maxilla (43%), followed by maxillary retrognathism with a normal mandibular position (19.6%), while the combination of maxillary retrognathism and mandibular prognathism was found to be rare (< 5%). Subjects with maxillary retrognathia, appeared to also have a vertical facial pattern, suggesting a tendency towards vertical growth as a possible compensation mechanism. Those with mandibular prognathia tended to exhibit a horizontal facial growth pattern and typically included more pronounced dento-alveolar compensation, that is, proclination of maxillary and retroclination of mandibular incisors. There were no differences observed in gender, overjet or soft tissue profiles between different sagittal skeletal types. Dominant protrusive mandible in Croatians can be related to European Caucasian ancestry, where this entity is historically described as 'Habsburg jaw'.