PURPOSE

Mandibular second molar (M2M) impaction is a serious eruption disorder. The purpose of this systematic review was to analyze the therapeutic approaches for M2M impaction. The objective of the meta-analysis was to summarize the success of the surgical, surgical-orthodontic, and orthodontic treatment.

METHODS

A PRISMA-guided search strategy was conducted by 2 authors in 5 databases up to January 2023. Randomized and nonrandomized clinical trials were considered. Case reports, case series with<5 patients, and reviews were excluded. Methodological quality was assessed using Newcastle-Ottawa scale and Cochrane Collaboration tool for nonrandomized and randomized clinical trials, respectively. Outcomes were as follows: 1) treatment success rate defined by the repositioning of impacted M2M in the dental arch with normal functional occlusal relationship and periodontal health; 2) time-to-repositioning as time-to-event analysis; and 3) complications. Meta-analysis examined treatment success differences with 3 approaches: orthodontic (uprighting maneuvers/traction), surgical (surgical procedures/strategic extractions), and surgical-orthodontic (combined surgical and orthodontic procedures) as the exposure variable. The quantitative analysis also compared the success rate using third molar removal as the secondary predictor variable. The χ test determined the statistical heterogeneity (I2); a cut-off of 70% was used to select the common or random effects model. Odds ratio (OR) and 95% confidence interval (CI) were recorded.

RESULTS

A total of 1,102 articles were retrieved. After full-text reading, 16 articles were included and 1008 M2Ms were analyzed. Nine studies had fair quality, 6 studies had good quality, and 1 had unclear risk of bias. Managing impacted M2Ms showed a moderate to high success rate (66.7 to 100%). Significant differences favoring surgical treatment over orthodontic treatment were observed for M2M uprighting (OR = 4.97; CI: 1.49 to 16.51; P = .01).No differences were detected comparing surgical and surgical-orthodontic treatment (OR = 1.00; CI: 0.03 to 37.44; P = .99), or orthodontic and surgical-orthodontic treatment(OR = 4.14; CI: 0.43 to 40.14; P = .22).Third molar removal showed no significant correlation with M2M uprighting (OR = 1.98; CI: 0.24 to 16.03; P = .5).

CONCLUSION

Despite study limitations, both orthodontic and surgical management of impacted M2M can be effective suggesting that clinicians are able to choose best treatment for most cases.