Do the various interceptive treatment modalities improve the position of palatally displaced permanent canines? A meta-analysis

Background Removal of maxillary primary canines and other interceptive treatment modalities in the mixed dentition have been suggested as methods used to increase the rate of normal eruption of palatally displaced permanent canines (PDCs). However, the information on the overall effect on PDCs' position has been inconclusive. Objective To assess whether this practice improves the position of PDCs and to investigate the quality of the evidence. Search methods Unrestricted searches in 7 databases and manual searching of the reference lists in relevant studies were performed up to June 2022 (Medline via PubMed, CENTRAL, Cochrane Database of Systematic Reviews, Scopus, Web of Science, ClinicalTrials.gov, ProQuest Dissertations, and Theses Global). Selection criteria We looked for data on the positional changes of PDCs (mesial inclination, vertical position, canine crown cusp tip to midline) from randomized controlled trials assessing the various interceptive treatment modalities. Data collection and analysis Following study retrieval and selection, relevant data were extracted, and the risk of bias was assessed using the Cochrane Risk of Bias 2 Tool. Exploratory synthesis and meta-regression were conducted using the random effects model and the overall quality of the available evidence was assessed with the Grades of Recommendation, Assessment, Development, and Evaluation approach. Results Five studies (3 at low risk of bias) were identified, involving 238 individuals, followed for up to 18 months post-intervention with OPG (orthopantomogram) or CBCT (cone-beam computed tomography). Exploratory data synthesis showed that PDCs' position improved more in the extraction sites compared to non-extraction. Analysis of the studies at low risk confirmed the above observations (6- and 12-month). Improvements were observed in patients using headgear after extraction of primary canines compared to extraction alone, but not in patients with double extraction of primary canines and first molars. The quality of available evidence was rated at best as moderate. Conclusions Interceptive treatment modalities in the mixed dentition may improve the position of PDCs. However, more studies are necessary in order to determine the clinical significance of the changes. Registration PROSPERO (CRD42015029130).