Short-Term Changes in the Occlusal Contacts During Anterior Segmental Orthodontic Treatment With Clear Aligners in Adult Patients.

Objective

To compare ClinCheck-predicted and achieved maxillary occlusal contact areas immediately after an initial 14-aligner anterior segmental sequence without programmed posterior movement.

Materials And Methods

This retrospective study included 31 adult women treated with 14 maxillary and mandibular clear aligners. Bilateral first premolars through second molars were digitally locked. Predicted stage-14 models and intraoral scans obtained immediately after aligner 14 and before refinement were assessed at maximum intercuspation. Contact regions at 0.00-mm clearance were quantified with ImageJ. The primary outcome was the patient-level total posterior achieved-minus-predicted difference. Tooth-type differences were analysed using patient-clustered generalized estimating equations with Holm adjustment; bite-ramp comparisons were exploratory.

Results

Predicted and achieved total posterior areas were 63.71 ± 36.56 and 30.30 ± 18.26 mm2, respectively (mean difference, -33.41 mm2; 95% CI, -44.42 to -22.40; p < 0.001). After Holm adjustment, the achieved central-incisor area was 0.49 mm2 greater than predicted (p = 0.003), whereas areas were smaller at the first premolars, second premolars, first molars, and second molars by 3.09, 5.44, 11.46, and 13.42 mm2, respectively (adjusted p ≤ 0.016). Lateral-incisor and canine differences were not significant. Bite-ramp groups did not differ significantly.

Conclusion

After 14 aligners, the achieved posterior contact area was substantially smaller than predicted despite no programmed posterior movement. This early discrepancy supports direct evaluation of posterior contacts before refinement.