Does head and cervical posture correlate to malocclusion? A systematic review and meta-analysis

Background: The association of head and cervical posture with malocclusion has been studied for many years. Despite extensively encouraging researches, no conclusive evidence has been reached for clinical application. Objective: To identify the question “Does head and cervical posture correlate to malocclusion?”, a systematic review and meta-analysis based on the available studies were carried out (PROSPERO registration number: CRD42022319742). Methods: A search of PubMed, Embase, Cochrane Library, and the grey literature was performed without language restrictions. The study screening, data extraction, risk-of-bias evaluation and methodological quality assessment were performed by two independent investigators. When a disagreement arose, a third author was consulted. Results: 6 original cross-sectional studies involving 505 participants were included, which were of moderate methodological quality. NL/VER in Class Ⅱ group and NL/CVT in Class Ⅲ group showed significant differences compared to Class Ⅰ group, but no significant differences were observed in most of the variables like NSL/VER, OPT/CVT, OPT/HOR, CVT/HOR, NSL/OPT, NSL/CVT, NL/OPT in Class Ⅱ and Ⅲ groups. Conclusions: The results suggested that the current research evidence is not sound enough to prove the association of head and cervical posture with sagittal malocclusion. Better controlled design and a larger sample size are required for clarifying this question in future study.