Facial asymmetry – aetiology, classification and diagnostics based on the literature

Introduction
Causes of asymmetry can be congenital, developmental or acquired. The classifications of asymmetry are based on various criteria. The simplest classification depends on the plane which is disturbed: asymmetries in relation to the transverse, vertical or sagittal planes. Regarding the diagnostics of facial asymmetry, the patient’s clinical examination and additional examinations such as 2D and 3D radiological examinations as well as bone scintigraphy are vital. Aim: The aim of the study was to present the aetiology, classification and diagnostics of facial asymmetry in patients presenting for orthodontic treatment.

Material and methods
A review of the literature was conducted using the PubMed database from the years 1986–2019 and the following keywords: facial asymmetry, dental arch asymmetry, PA cephalometry, CBCT. The papers which were the most suitable for this subject were selected.

Results
Facial asymmetries are a wide range of disorders of different aetiologies. CBCT is currently the most modern examination allowing for precise diagnostics.

Discussion
According to the literature, in 74% of cases, asymmetry was observed in the lower part of the face, in 36% – the middle part and in 5% – the upper part. The greatest asymmetry was observed in relation to the mandible, moderate – the zygomatic area, and the smallest – the orbital area. Currently, CBCT scan analysis is the most useful method of diagnosing facial asymmetry. It allows to perform linear, angular and volumetric measurements, and the need to take cephalometric radiographs in the PA projection and submentovertex images is completely eliminated.

Summary
To plan the treatment of a patient with facial asymmetry in a proper way, a detailed diagnosis must be performed, taking into account the fact that not all abnormalities are pathological and require treatment.