The nature of the adhesive greatly influences the resultant bond strength, the risk of enamel damage, and the extent of residual composite on the teeth.

No abstract

This study contributes valid data for the soft-tissue profile prediction in orthognathic surgery.

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Objective: To investigate changes in dental arch configuration, relationship, and malocclusion directly after Class II malocclusion treatment with a Balters bionator modified by Ascher as well as 20 years after treatment. Materials and Methods: Orthodontic dental cast analysis of 18 patients with skeletal Class II treated with a bionator without any additional fixed therapy was performed with a digital caliper at three stages: before (T0), after (T1) and 20 years after (T2) treatment. Arch perimeter and depth, intermolar and intercanine distance, overjet, overbite, sagittal molar and canine relationship, mandibular incisor irregularity (Little's index), and malocclusion (PAR index) were assessed. Results: During treatment (T0–T1), upper arch perimeter significantly increased with a significant decrease in the upper and lower arch perimeter long-term (T1–T2), whereas corresponding arch depths changed only slightly in both periods. Transverse intermolar width increased significantly during treatment, remaining almost constant from T1 to T2. Lower intercanine distance remained fairly unchanged during treatment, but decreased significantly during follow-up. Lower incisor irregularity improved slightly during treatment but increased significantly long-term. After treatment, sagittal molar relationships on both sides were improved, overjet and overbite reduced; these significant changes remained stable long-term. The peer assessment rating (PAR) index was significantly lower after treatment and increased insignificantly during follow-up. Conclusions: 20 years after bionator treatment without additional fixed appliances, the improved sagittal relationship and the reduced overjet and PAR index remained fairly stable. Long-term changes are most likely due to physiological aging processes and are not associated with bionator treatment.