Post-treatment Stability of Maxillary Arch Dimensions in Unilateral Cleft Lip and Palate: A Systematic Review.

Cleft lip and palate (CLP) are structural anomalies resulting from the failure of craniofacial prominences to fuse during embryonic development. Orthodontic treatment seeks to address these conditions by improving dentofacial balance and restoring oral function, but long-term post-treatment stability continues to pose a challenge. This systematic review included a literature search of four electronic databases (PubMed, Scopus, Web of Science, and Cochrane CENTRAL) to identify observational evidence on the stability of orthodontic treatment in CLP. Six studies, comprising three cohort studies and three case reports, were included, totaling 130 participants (110 individuals with CLP, including 54 males and 56 females, and 20 non-cleft controls). Cohort evidence suggested that maxillary arch form may influence post-treatment stability, with symmetrical arches demonstrating minimal relapse, whereas arches with anterior collapse or combined segment collapse showed a higher tendency toward relapse. Across cohort studies, maxillary arch dimensions generally decreased during follow-up regardless of retainer or prosthesis use. Fixed partial dentures appeared to offer better stability for anterior measurements than implant-supported prostheses, while greater instability was consistently observed in the molar region. Case reports described appropriate orthodontic approaches in complex cleft presentations, with variable reporting of adverse events, and also reported stable transplanted teeth without evidence of ankylosis or root resorption. Overall, stability outcomes may be influenced by the retention strategy, arch form severity, and prosthesis type and duration. Further well-designed observational studies with standardized stability outcomes and consistent follow-up intervals are needed to identify the best approaches to enhance long-term stability.