Periodontal tissue changes after crown lengthening surgery: A systematic review and meta-analysis

Crown lengthening is one of the most common periodontal surgical procedures carried out to increase the amount of supragingival tooth structure. There is a lot of literature on crown lengthening surgeries, but very few systematic reviews comparing treated and adjacent sites over a six-month period. The purpose of this systematic review and meta-analysis was to evaluate the outcomes of crown lengthening surgery in terms of changes in periodontal clinical parameters and periodontal tissue stability between treated and adjacent sites.Electronic databases were searched up to 28 February 2022 with no restriction on publication status. A manual search of journals was also performed. Predefined inclusion and exclusion criteria were used to select the relevant articles that assessed dimensional changes in periodontal tissues after crown lengthening surgery. The risk of bias was assessed using the JBI critical appraisal checklist. Data meta-analysis was performed using a statistical software program.A total of 78 studies were identified, of which, four clinical controlled trials containing 182 crown lengthening surgical procedures across 111 participants were included. Meta-analysis showed no statistically significant changes after three or six months in terms of supracrestal tissue attachment levels, bone level and probing pocket depth between treated and adjacent sites. However, clinical attachment level changes were statistically significant, favouring adjacent teeth at six months.Within the limitation of this systematic review, crown lengthening surgery results in stable periodontal tissues over time according to the acceptable periodontal healing parameters. Further evidence is still required to substantiate these findings.