Evaluation of Alveolar Bone Height Changes Following Clear Aligner Therapy: A Retrospective Analysis Using...

The rising demand for clear aligners, attributed to their discreet appearance and removability, underscores the need to assess their effects on periodontal health, particularly alveolar bone height. This study aimed to investigate the changes in alveolar bone height in patients undergoing clear aligner therapy using pre- and post-treatment orthopantomograms (OPGs), contributing to the evidence for their clinical application.

This retrospective study was conducted at Kothiwal Dental College and Research Centre (Moradabad, UP, IND) on OPG records of 50 periodontally healthy adults (aged 18 to 40 years) treated with clear aligners for non-extraction cases involving maxillary and/or mandibular expansion. Patients with systemic disease, periodontal disease, or prior orthodontic treatment were excluded. Pre- and post-treatment OPGs obtained using standardized settings were evaluated for alveolar bone height from the cementoenamel junction to the alveolar crest on the incisors, canines, and first molars. Two calibrated orthodontists performed blinded measurements with intraclass correlation coefficients ≥0.90, ensuring reliability. Data were analyzed using paired t-tests for pre- and post-treatment comparisons and multivariable linear regression to assess confounding factors (age, sex, and treatment duration). Statistical significance was set at p < 0.05.

Significant changes in alveolar bone height were observed across all regions (p < 0.001), with the mandibular anterior region showing the greatest alveolar bone loss of 0.31 mm, followed by the mandibular posterior (-0.30 mm), maxillary anterior (-0.21 mm), and maxillary posterior regions (-0.07 mm). Class I and II malocclusions exhibited significant changes (-0.90 mm in class I and -0.86 mm in class II), whereas class III malocclusions were not significant (-0.34 mm, p = 0.078). Multivariable linear regression analysis revealed no significant associations between the examined parameters and overall alveolar bone level changes in patients undergoing clear aligner therapy (p > 0.05) for all variables except sex (p = 0.041) and treatment duration (p = 0.017), with relatively small effect sizes.

Clear aligner therapy induced minimal but significant changes in alveolar bone height, particularly in the mandibular region, supporting periodontal safety. These findings underscore the need for careful treatment planning and periodontal monitoring to optimize outcomes in modern orthodontics.