An investigation of mandibular asymmetry and associated soft-tissue characteristics among adults: A digitalized orthopantomographic and photographs assessment

Introduction: There are many controversies behind the topic of mandibular asymmetry. Conflicts include: gender predilection, soft tissue correlation and what is considered normal asymmetry. Consequently, this study was done to investigate the prevalence and severity of mandibular asymmetry among adults in a sample from orthodontic clinics and to assess the soft tissue correlation and gender predilection. Methods: Mandibular asymmetry was investigated on a standardized digitalized orthopantomograms of 793 adults attending Riyadh Elm University, orthodontic clinic following strict eligibility criteria. This study started in July 2020 to October 2021. Asymmetry index (AI) used to analyze the prevalence and gender incidence. Soft tissue assessment for 87 of the mandibular asymmetric participants was done on a standardized photograph checking the soft tissue correlation measuring the area, perimeter and compactness for the two sides of the lower third of the face. The resulted ratios correlated with (AI). Both radiographic and photographic assessment was done on AutoCAD LT 2021 software (version R.46.M.1748). Results: Considering participants of 3% or greater in Asymmetry Index (AI) as asymmetric. Therefore; 20.9% of males' subjects represent mandibular asymmetry, while the incidence in females was only 13.69%. Moreover, there's no significant link between hard and soft tissue asymmetry, the correlation (r) between Asymmetric index (AI) and area ratio (AR) was recorded as .062 indicating a weak positive relationship. Conclusion: Ultimately, it can be concluded that soft tissue is not associated with hard tissue asymmetry. Moreover, Radiographic based mandibular asymmetry showed high prevalence rate in both adult genders with higher incidence in males.