Objectives: Tooth wear, additional to the physiologic alterations of the dentition, may occur during orthodontic treatment. The objective of the present review was to investigate systematically the literature relevant to its progression in patients having undergone comprehensive orthodontic treatment.
Data sources: Search without restrictions in eight databases since inception and hand searching until October 2017 was performed.
Data selection: Studies evaluating tooth wear immediately before and after the completion of orthodontic treatment with fixed appliance were evaluated independently and in duplicate.
Data extraction: Following study retrieval and selection, data on volumetric and surface tooth wear was extracted. Individual study risk of bias assessment was performed using the Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tool, and the overall quality of the evidence was assessed with the Grades of Recommendation, Assessment, Development and Evaluation approach.
Data synthesis: All three finally included studies reported wear of teeth during the period of treatment but were at serious risk of bias. Two of them investigated tooth wear by 3D volumetric measurements and one used grading scales. The mean volume reduction was 1.02 mm3 per tooth for the incisor group [95% Confidence Interval (CI): 0.84-1.20], 1.62 mm3 for the canines [95% CI: 0.8-2.38; I2 = 96%; random effects method] and 0.95 mm3 for premolars and molars [95% CI: 0.84-1.07]. The overall quality of evidence limited the confidence in the observed estimates.
Conclusions: Varying degrees of tooth wear were reported after comprehensive orthodontic treatment. Further studies are needed in order to elucidate how much is associated with orthodontic treatment and/or physiologic alterations of the dentition.
Keywords: Meta-analysis; orthodontic treatment; systematic review; tooth wear; volumetric assessment.