“Comparative Evaluation of Clinical Effectiveness of Clear Aligners and their Associated Factors in Extraction and Non Extraction Cases – A Retrospective Study”

Abstract

Introduction: Clear aligner therapy (CAT) has emerged as a popular alternative to fixed appliances, offering advantages in esthetics, comfort, and oral hygiene. While its effectiveness in mild-to-moderate malocclusions is established, limited evidence exists comparing outcomes in extraction versus non-extraction cases.

Aim: To evaluate and compare the clinical effectiveness of CAT in extraction and non-extraction cases using the Peer Assessment Rating (PAR) index, with particular focus on treatment duration and refinement frequency.

Material and Methods: A retrospective study was conducted on 24 patients (12 extraction, 12 non-extraction) treated with clear aligners between 2021 and 2024. Pre- and post-treatment digital models were assessed using the PAR index. Treatment duration and number of refinement scans were recorded. Statistical analysis included paired and unpaired t-tests with significance set at p < 0.05.

Results: Both extraction and non-extraction groups showed significant reductions in total weighted PAR scores (extraction: 29.36 ± 7.93 to 4.91 ± 4.48; non-extraction: 16.55 ± 8.86 to 3.18 ± 5.90, p < 0.001). Post-treatment outcomes were comparable between groups; however, extraction cases exhibited significantly greater reductions in lower anterior segment alignment, overjet, and total PAR scores (p < 0.01). Extraction cases required more refinements (2.82 ± 0.75 vs. 1.00 ± 0.63, p < 0.001) and longer treatment duration (25.48 ± 5.14 vs. 10.52 ± 2.71 months, p < 0.001).

Conclusion: Clear aligners are effective in achieving favourable occlusal outcomes in both extraction and non-extraction cases. Although extraction cases demand longer treatment duration and more refinements, they achieve comparable final results, supporting the use of CAT in complex malocclusions with proper case selection and patient counselling.