A COMPARATIVE EVALUATION OF THE ACCURACY OF TOOTH PREPARATION FOR VENEERS: CONVENTIONAL METHODS VERSUS DIGITALLY GUIDED TECHNIQUES – AN IN VITRO STUDY

This in vitro study aimed to compare the accuracy of three different veneer preparation techniques: conventional
freehand (CM), silicone reduction guides (ERG), and CAD/CAM 3D-printed guides (DG). Thirty maxillary central
incisor typodont teeth were randomly assigned to three groups (n = 10 per group). A single experienced operator
carried out all preparations to minimize operator variability. The CM group used calibrated depth-cut burs without
any guide, the ERG group used silicone indices fabricated from diagnostic wax-ups, and the DG group used digitally
designed and 3D-printed reduction guides. Pre-preparation and post-preparation scans were obtained and analyzed
using Geomagic Control software to evaluate the mean absolute difference (MAD) and standard deviation (SD) of
tooth reduction. The results revealed that the DG group exhibited the highest accuracy and precision in maintaining
the planned reduction depth, followed by the ERG group. While the ERG technique provided improved control over
freehand preparation, some deviations were observed due to the inherent flexibility and distortion of the silicone
material. The CM group showed the least accuracy, with greater variability in reduction. Overall, the digitally guided
method demonstrated superior control, precision, and conservation of tooth structure, highlighting its clinical
advantage in aesthetic veneer preparations.