The effect of extraction of lower primary canines on the morphology of dental arch: A systematic review and meta-analysis

Background The beneficial effect of the extraction of primary canines in the resolution of incisor irregularity and its side effects are controversial. Aim To systematically review the effects of the extraction of primary canines in incisor irregularity and dental arch morphology. Design Controlled non-randomized (non-RCT) and randomized clinical trials (RCT) evaluating children treated with extraction of primary canines compared with those without intervention. Results A total of 984 articles were found, of which two RCTs and one non-RCT met the inclusion criteria. Both had a low RoB. A high level of evidence was observed through GRADE. A meta-analysis showed the extraction of primary canines produced a significant decrease in incisor irregularity (95% CI: -3.56, -2.09 mm). This decrease, however, was associated with a reduction of arch length (95% CI: -1.58, -0.94 mm), intermolar width (95% CI: -0.61, -0.22 mm), and overjet (95% CI: -075, -018). A mild overbite increase was found (95% CI: 0.10, 0.76 mm). Conclusion A high level of evidence showed that the extraction of primary canines improved incisor irregularity in the mixed dentition. Side effects included reduced arch length and intermolar width. A slight reduction in overjet and a mild increase in overbite were also observed. When they are not part of the treatment goal, these occlusal changes can be prevented by installing a lingual arch.

Automated summary

A systematic review of the effects of extracting primary canines on incisor irregularity and dental arch morphology showed that in the mixed dentition, primary canine extraction can improve incisor irregularity but may result in reduced arch length and intermolar width, as well as decreased overjet and increased overbite.