The association between posterior unilateral crossbite and craniomandibular asymmetry: a systematic review

The aim of this study was to evaluate the association between posterior unilateral crossbite and craniomandibular asymmetry in children, adolescents and adults through a systematic review of the literature.

A literature search was performed utilizing the Medline database (Entrez PubMed) and the Cochrane Central Register of Controlled Trials (CENTRAL) covering the period from January 1970 to December 2011.

The literature included reports and studies related to children, adolescents and adults with a history, presence and treatment of posterior unilateral crossbite. Prospective and retrospective studies with untreated, as well as normal controls and clinical trials comparing at least two treatment strategies were also identified.

The search strategy resulted in 15 relevant articles, which met the inclusion criteria. After data extraction and detailed evaluation 4 studies were deemed to have a high risk of bias due to low sample size and hence were excluded from the review. This left 11 studies for qualitative evaluation. The studies were of medium or low methodological quality with serious shortcomings and the results were contradictory. The majority of studies suggested a possible association between posterior unilateral crossbite and positional mandibular asymmetry.

An evidence-based conclusion could not be drawn due to the low quality level of the retrieved studies and future study designs incorporating three-dimensional evaluation techniques are recommended.