Predictability Of Digital Wax-up Of CAD/CAM-Restorations In Severe Tooth Wear

Objectives: Patients with severe tooth wear were treated with LAVA Ultimate restorations. Aim of this study was to digitally quantify the differences between the digital wax-up and the final clinical result of the restorative treatment.
Methods: Adult patients with severe, generalized tooth wear were included in this prospective clinical trial of the Radboud Tooth Wear Project (with approval of ethical comity). An increase of vertical dimension of occlusion (VDO) was necessary in all cases. Using a full digital workflow (based on 3D-scans of Truedef, 3M) all teeth were treated with indirect CAD-CAM composite restorations of LAVA Ultimate (3M). A full digital wax-up was made and afterwards the restorations were milled and polished. Restorations were adhesively cemented with Relyx Ultimate (3M) and as veneering material Filtek Supreme XTE (3M) was used. After treatment a new digital scan was made. To compare differences between the wax-up and final result the maximum height difference was measured per restoration of all premolars and molars (8 patients, n=219). A modified reference based best fit technique was used (Geomagic®). Statistical analysis has been performed at patient-level, jaw-level and tooth-level, using paired t-tests, independent t-tests and one-way ANOVA (p<0.05)
Results: The mean maximum height difference of the final result, after placement of all restorations, was significantly higher (238.9 ± 610.3μm) compared to the situation of the wax-up (p<0.001). A significant effect was found between patients (15.1 – 471.6μm) (p<0.001). No statistical differences were found between jaw or tooth type (p>0.074).
Conclusions: A statistically significant difference was found between the digital wax-up and the final result when placing indirect composite restorations using a digital workflow. In all cases the restorations turned out to be thicker than originally designed.