Objective: Positional and structural asymmetries of the mandible are prominent among craniofacial skeletal disorders that are associated with spinal curvatures in various planes. Our objective is developing a comprehensive, rapid and easily reproducible image processing method of mandibular asymmetries readily applicable by colleagues of other specialities diagnosing postural abnormalities.
Methods: Rasterstereographic dorsal surface analysis was performed on 271 children (115 boys, 156 girls, mean age 11.78 years, SD 2.01) undergoing orthodontic screening, identifying 6 measures indicating sagittal and frontal disorders. Orthopantomograms complemented routine examinations, they were analysed with our self-developed Asymmetrix X software registering 6 horizontal, 9 vertical asymmetry indices and 21 vertical distances. Orthopaedic and mandibular measures were compared using stepwise linear regression.
Results: Significant associations were observed between the sagittal postural measures and certain vertical asymmetry indices of the ramus of the mandible. Also the TgcGoL and GnGoL distances measuring the position of the corpus of the mandible relative to its ramus showed significant associations with the cervical fléche (p=0.024, p=0.016, respectively). We haven't found relationships between the frontal posture measures and the mandibular asymmetry measures.
Conclusions: Asymmetrix X determining reference points very accurately enables linking asymmetries of mandibular subregions to abnormalities of various spine segments. The extended list of measurement points enabled indirectly describing the slope of the mandibular basal plane. The position of the corpus measured this way is closely related to the sagittal head posture, making lateral X-ray superfluous, decreasing the radiation load of the children.