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.