Accuracy of incisor intrusion in adult female nonextraction deep overbite cases with clear aligner treatment

Objective

To evaluate the accuracy of incisor intrusion in nonextraction deep overbite cases in adult female patients treated with clear aligners (Invisalign, Align Tech, USA), and to investigate the predictability of clear aligner treatment for deep overbite correction.

Methods

This retrospective study included thirty-three adult female patients who underwent nonextraction followed by clear aligner treatment. The initial, predicted, and actual models were exported from ClinCheck. For nine completed cases, pre- and posttreatment cone-beam computed tomography (CBCT) data were collected. The amount of intrusion achieved for the incisors was measured, and the intrusion efficacy and deep overbite correction were calculated. Statistical analysis was performed using paired-samples t tests or Wilcoxon signed-rank tests (significance set at P < 0.05), with effect sizes (Cohen's d) calculated for clinically meaningful differences and intraexaminer reliability assessed using the intraclass correlation coefficient (ICC).

Results

Significant differences were observed between the predicted and actual vertical movements of all teeth, with the greatest discrepancy observed in the maxillary central incisors. The average accuracy of intrusion for deep overbite correction in the first phase was 45.54 %. For the completed cases, the average correction for deep overbite was 41.18 %, which was comparable to the results achieved in the 1st phase (intital treatment stage).

Conclusions

In nonextraction adult female patients treated with clear aligners, the first phase demonstrated the most overbite correction with aligners, whereas additional refinement treatment did not significantly enhance the orthodontic outcome. Almost every patient with deep overbite required some degree of overcorrection and further refinement treatments to achieve optimal results.

Clinical Significance

This study aimed to i) evaluate the accuracy of incisor intrusion with deep overbite correction over several refinements, ii) determine the discrepancy of individual teeth in vertical movements in the different phases of the aligners, and iii) assess the predictability of clear aligners for deep overbite correction.