Assessment of Clinical Predictability of Overbite Reduction and Curve of Spee Levelling in Clear Aligner Treatment

Objective: This retrospective study aims to assess the predictability of Overbite (OVB) reduction and Curve of Spee (COS) levelling in patients with deep bite malocclusion treated with Clear Aligner Therapy (CAT). The research evaluates the accuracy of the prescribed movements in growing and non-growing patients. Materials and methods: Thirty-six patients treated with Invisalign from January 2018 using SmartTrack were included. Digital models at pre-treatment, virtual plan and post-treatment phases were collected and analysed using Geomagic Control X. Accuracy was assessed for COS levelling, OVB reduction and individual tooth movements. Statistical analyses included descriptive statistics, paired t-tests and linear regression between accuracy of the movements and the age of the patient. Results: The study found that the prescribed movements in ClinCheck often overestimated the achieved outcomes. The mean accuracy for COS levelling was 62%, and for OVB reduction, it was 61%. No significant association was observed between the accuracy and the age of the patient. Conclusion: Clear Aligner Therapy demonstrated moderate accuracy in achieving prescribed movements for COS levelling and OVB reduction. Clinicians should exercise caution in virtual treatment planning and may need to consider potential modifications to software projections to enhance desired outcomes. Further research comparing different aligner protocols and brands is warranted to advance understanding and improve treatment predictability.