Effectiveness of extraction of the primary canines for the interceptive management of palatally displaced permanent canines - a meta-analysis

Abstract

Although extraction of primary canines in the mixed dentition has been suggested as a measure to prevent impaction of palatially displaced permanent canines (PDC), the relevant evidence has been inconclusive. The aim of this study was to investigate the effectiveness of this practice. Search without restrictions for published and unpublished literature and hand searching took place. Data on the prevalence of physiologic PDC eruption, patient reported outcomes, adverse effects and economic evaluation data from randomized controlled trials (RCTs) that compared extraction of primary canine to no treatment (including delayed treatment) were reviewed. The random effects method of combining treatment effects was used and the individual study risk of bias and the overall quality of the available evidence (confidence in the observed effect estimates) were assessed using the Cochrane Risk of Bias Tool and Grades of Recommendation, Assessment, Development and Evaluation approach, respectively. We initially identified 1878 references and finally included data from 5 RCTs involving 329 patients with 479 PDC in total, following them for up to 48 months post! intervention. One study also presented data for the 12-month evaluation. Two studies were at low and the rest at high risk of bias. At the 12-month evaluation, extraction of the primary canine does not result in a statistically significant benefit compared to no treatment [Risk Ratio (RR): 1.537; 95% Confidence Interval (CI): 0.656 – 3.601; 1 study, n = 67 participants]. Beyond 12 months, overall, there is only low-quality evidence that extraction of primary canines provides a statistically significant benefit compared no treatment or delayed treatment [RR: 1.784; 95% CI: 1.376 – 2.314; 5 studies, n = 214 participants; I2 = 0%]. Analysis of the studies at low risk of bias confirmed the abovementioned result [RR: 1.713; 95% CI: 1.226 – 2.394; 2 studies, n = 91 participants; I2 = 0%]. Moreover, the intervention did not result in a statistically significant benefit compared to no treatment regarding root resorption of adjacent permanent teeth [RR: 0.602; 95% CI: 0.277 – 1.308; p = 0.200 n = 67 participants] Extraction of primary canines in mixed dentition may increase the chance of subsequent successful eruption of PDC in the long term. However, better study standardization and reporting of long follow-ups are necessary.