Periodontal outcomes of surgically exposed and orthodontically aligned buccally impacted maxillary canines: A systematic review and meta-analysis

Objective: This systematic review aimed to compare periodontal outcomes of surgically exposed and orthodontically aligned buccally impacted maxillary canines to spontaneously erupted maxillary canines. Data sources: An unrestricted search was carried out of indexed databases (Medline, EMBASE, Web of Science and Scopus), reference lists of included studies, and grey literature published until December 2023. Data selection: Observational and experimental studies that addressed the focused question 'Do periodontal outcomes of buccally impacted maxillary canines that were surgically exposed and subsequently extruded and aligned using orthodontic alignment differ from those of spontaneously erupted maxillary canines?' were included. Data extraction: Study screening, selection and data extraction were performed independently by two authors, with disagreement resolved by a third reviewer. The risk of bias was assessed using the JBI Critical Appraisal Checklist and GRADE approach. Results: A total of 857 citations were found and five studies were eligible for inclusion. Supragingival plaque accumulation and gingival inflammation were similar between impacted canines and their contralaterals in most studies. Meta-analyses revealed no significant differences in keratinised tissue width (prospective studies: MD = -0.28, 95% confidence interval [CI] = -1.13-0.56, I-2 = 78%; retrospective studies: MD = 0.61, 95% CI = -1.51-2.72, I-2 = 94%). However, a meta-analysis of prospective studies showed slightly greater mean probing depth for impacted canines compared to their contralateral canines (prospective studies: MD = 0.16, 95% CI = 0.04-0.28, I-2 = 0%). The evidence certainty for keratinised tissue width and probing depth outcomes was low. Conclusion: Surgically exposed and orthodontically aligned buccally impacted canines have slightly greater probing depths, potential bone loss and increased clinical crown length, compared to their counterparts. However, these small differences (<1 mm) are unlikely to be clinically significant.