Skeletal components of class III malocclusions and compensation mechanisms

Abstract

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'.

Distinguishing Hard and Soft Tissue Facial Morphology Among Class I and Class Iii Children: A Cephalometric Assessment

“…Our results showed that the subjects with class III malocclusion had larger mandibles (B-y distance) and prominent soft tissue pogonion. In accordance with our results, several studies 1,13,16 showed that there was a tendency of more horizontal growth pattern in the mandibles of Class III subjects.…”

Distinguishing Hard and Soft Tissue Facial Morphology Among Class I and Class Iii Children: A Cephalometric Assessment

“…Singh et al 14 Our results showed that the subjects with class III malocclusion had larger mandibles (B-y distance) and prominent soft tissue pogonion. In accordance with our results, several studies 1,13,16 showed that there was a tendency of more horizontal growth pattern in the mandibles of Class III subjects.…”

“…2 According to Spalj et al, 13 Class III subjects with maxillary retrognathia have an increased vertical growth pattern. In a cross sectional study, Bacetti et al 17 studied craniofacial characteristic of 1091 class III children and found a growth trends toward accentuated Class III profile and increased vertical facial dimension towards the late developmental stages.…”

Retrognathic maxilla in “Habsburg jaw”

“…It is interesting to note that the dentoskeletal features of Joanna of Austria are similar to those of Class III European white subjects with maxillary retrognathism who demonstrate a tendency toward vertical growth as a possible compensation mechanism of Class III malocclusion. 26 On the contrary, Class III subjects with mandibular prognathism tend to exhibit a horizontal facial growth pattern and typically include more pronounced dentoalveolar compensation, that is, proclination of maxillary and retroclination of mandibular incisors. 26 The Class III long-face profile that affected Joanna of Austria is clearly testified by the portraits of the noble woman ( Figure 5).…”

“…26 On the contrary, Class III subjects with mandibular prognathism tend to exhibit a horizontal facial growth pattern and typically include more pronounced dentoalveolar compensation, that is, proclination of maxillary and retroclination of mandibular incisors. 26 The Class III long-face profile that affected Joanna of Austria is clearly testified by the portraits of the noble woman ( Figure 5). Joanna appears with a peculiar type of ''Habsburg jaw'' as the Class III profile was related to the presence of a marked maxillary retrusion rather than to mandibular prognathism.…”