Normal variation of mandibular asymmetry in children

Objective: To explore the normal variation of asymmetry in mandibles of children in the age group of 1 to 12 years. Materials and Methods: The study group consisted of 92 cadaveric mandibles of children with a dental age of 1 to 12 years old in possession of ACTA (Academic Centre for Dentistry Amsterdam), Faculty of Dentistry, the Netherlands. 3D models of the mandibles were obtained from CT-scans and hemimandibular volumes of all mandibles were calculated. The condylar height, ramus height, mandibular body length and the gonial angle were bilaterally determined using a novel landmark-based method, and the degree of asymmetry was calculated. Results: No relationship was found between dental age and asymmetry of the studied parameters (P <.05). The highest degree of asymmetry was found in the ramus height, whereas the gonial angle presented the lowest degree of asymmetry. A positive correlation was found between the asymmetry of the hemimandibular volume vs the height of the ramus (P <.05) and the length of the mandibular body (P <.05). An inverse correlation was found between the asymmetry of the ramus height vs the condylar height (P <.05), mandibular body length (P <.05) and gonial angle (P <.05). Conclusions: Mandibular asymmetries in children did occur (9.8% of the included mandibles presented with a relevant overall asymmetry of ≥3%) and were unrelated to age. The different segments of the mandible seem to compensate for each other, in order to maintain a functional equilibrium.