Purpose: To critically evaluate the periodontal parameters of patients receiving fixed labial and lingual orthodontic therapy.
Materials and Methods: The current systematic review was registered at PROSPERO. Clinical studies comparing the periodontal parameters between fixed labial and lingual orthodontic treatment were searched up to June 2022 in four electronic databases, and unpublished literature was searched at ClinicalTrial.gov. The risk of bias of randomised controlled clinical trials (RCTs) and non-randomised clinical trials (n-RCTs) was assessed using the Cochrane risk-of-bias tool 2.0 and the Risk of Bias in Non-randomised Studies of Interventions (ROBINS-I) assessment tool, respectively. The pooled periodontal parameters were calculated in random-effect meta-analyses. The confidence of evidence was assessed via the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.
Results: Eight studies involving 223 patients were included in the current study. The risk of bias was high for 2 RCTs and 3 n-RCTs, and moderate for 3 n-RCTs. Patients receiving fixed lingual orthodontic treatment showed a lower plaque index (MD = -0.14; 95%CI -0.27 to -0.02). No statistically significant difference was found in the bleeding on probing index (MD = 0.11; 95%CI -0.03 to 0.25), gingival index (MD = 0.02; 95%CI -0.06 to 0.11), and periodontal pocket depth ( MD = 0.06; 95%CI -0.16 to 0.27) between the two groups. The overall quality of the evidence was very low to low.
Conclusion: The present study indicates no obvious difference in periodontal parameters between the fixed labial and lingual orthodontic systems, although the overall quality was very low to low. Further RCTs with standardised outcome measures are needed.