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

Abstract

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.

Effects of orthodontic extraction on facial soft and hard tissue changes among average-angle skeletal class Ⅰ Chinese adults females:A 3D geometric morphometric study

“…In the study of adult patients with bimaxillary protrusion, Leonardi et al [17] found that the upper and lower lips were moved backward by 2 to 3.2 mm and 2 to 4.5 mm respectively after the extraction of the rst premolar, indicating that the rebuilding in soft tissue of the lips will occur with the movement of the teeth. Adults lack the ability to remodel soft tissue, suggesting that adult patients with thick lip can obtain better lip shape after tooth extraction, which is consistent with the research conclusions of some studies [18,19]. In addition, we also observed a decreased change in 1/3 face height and chin high and opposite in soft tissue angle in the extraction group, which might be that these cases were designed as moderate anchorage, and the molars move mesially, resulting in a counterclockwise rotation of the mandible [20,21].…”