Tertiary crowding is common after orthodontic treatment. The role of third molars in their development remains a subject of controversy. We aim to evaluate whether third molar removal affects long-term anterior alignment after orthodontic treatment. A systematic search was conducted in PubMed, Embase, Cochrane Library, and Google Scholar. Manual searches reference lists of included studies, selected orthodontic journals, and recent reviews. Included studies specifically addressed the following PICOT question: PICOT: In patients who do not wear retention devices after orthodontic treatment (P), does the extraction of wisdom teeth (I) compared to patients who retained their wisdom teeth (C) have an impact on the prevention of crowding (O) after at a minimum follow-up of one year after the end of the retention phase (T)? Study selection, data extraction, and risk of bias assessment were performed independently by two reviewers. Four studies met all inclusion criteria. All of them reported an increase in anterior crowding over time, regardless of third molar status. No statistically significant differences were found between groups. One study observed a smaller reduction in arch length in the extraction group. Overall, study quality was limited due to heterogeneity in treatment protocols, retention strategies, and measurement methods. Based on the very low certainty of evidence, there is no consistent indication that the presence or agenesis/removal of third molars meaningfully influences post-treatment anterior crowding. Therefore, routine prophylactic extraction for this purpose is not supported by the currently available evidence. Registration. PROSPERO: CRD42024546851.
Amberg et al. (Fri,) studied this question.
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