Mandibular symphysis morphology and lower incisor angulation in different anteroposterior jaw relationships and skeletal growth patterns – a cephalometric study

Abstract

Objective. The purpose of the present study was to assess the symphyseal morphology and lower incisor angulation in different anteroposterior relationship and in different growth patterns and to investigate whether the symphyseal morphology had any correlation with dentofacial parameters.
 Method. Random Sampling method and lateral cephalograms of 90 subjects, age group 16-30 years, were divided into 30 in each group, i.e. Class I, Class II & Class III after calculating the following parameters (ANB angle, wits appraisal). After that, groups were again divided into 10 in each subgroup i.e. Average, Horizontal and Vertical growers.
 Results. Results showed the increase in actual symphysis width, inclination of the alveolar part, total height of symphysis and reduction in overall width along with retroclination of lower incisors in class III subjects as compared to class I and class II. Similarly actual and overall width of the symphysis were decreased and inclination of the alveolar part, symphyseal height and symphyseal ratio were increased in vertical growers.
 Conclusion. The dimensions and configuration of Mandibular Symphysis in class III was found to be different than those in Class I and Class II relationships; the alveolar part of Mandibular Symphyseal compensated for the skeletal relationship in the Class III pattern. Mandibualr Symphysis dimensions were strongly correlated to anterior facial dimensions. Similarly the dimensions and configuration of Mandibular Symphysis was also different in vertical growers as compared to horizontal and average growers, moreover symphyseal morphology and lower incisor angulation had a correlation with dentofacial parameters.

The relation between mandibular symphysis and the Angle class in orthodontic treatment

“…Between the three dental classes, the height of the symphysis did not show significant differences, even though class III individuals were the ones with higher values. These results are in agreement with the results of other studies, which report that these individuals present greater vertical growth and that it is associated with an increase in cortical bone thickness [ 35 , 36 ].…”

“…Individuals with Class II Div.1 had a bigger 6). The symphysis showed variations, which may be associated with a natural compensation for malocclusion, influencing the position of the teeth and their relationship with other dento-craniofacial structures [8,19,[36][37][38].…”

“…The chin is one of the most visible structures of the face, not only in frontal view, but also in profile view, and its prominence is one of the facial features that society tends to associate with an individual’s personality. Thus, the treatment plan must take into account the morphology of the symphysis (height, width and inclination), the position of the lower incisors and the amount of bone available [ 28 , 29 , 35 , 36 , 50 ]. The treatment must consider both the hard tissues and the soft and the search for symmetry and proportionality of the face should prevail for a facial balance.…”

Novel cephalometric parameters for the assessment of vertical skeletal dysplasia

“…This study involved three groups (AGG, HGG, and VGG) defined using specific criteria: Y-axis, SnGoGn, and Jaraback ratio. [ 15 16 17 ] Our findings did not show any differences in the mean maxillary angle between AGG, HGG, and VGG. Notably, in our study, the maxillary angle was measured relative to the true angle.…”

“…The cephalograms were traced and then classified into average (normal), horizontal, and vertical growers using parameters, namely, the Y-axis, SnGoGn, and Jaraback ratio. [ 15 16 ]…”