Morphological Symmetry of Maxillary Anterior Teeth before and after Prosthodontic Planning: Comparison between Conventional and Digital Diagnostic Wax-Ups

OBJECTIVE: The aim of this study was to evaluate the impact of different prosthodontic planning methods on the morphological symmetry of maxillary anterior teeth. MATERIALS AND METHODS: In 13 patients receiving fixed prosthodontic treatment, dental models were obtained from the Oral Health Centre of Western Australia. Two forms of diagnostic prosthodontic planning were executed: conventional wax-up and digital wax-up. The asymmetry was evaluated at two levels: tooth morphological asymmetry (TMA) and anterior segment morphological asymmetry (ASMA). For the TMA, the labial surface of each anterior tooth was superimposed on a mirror image of the contralateral tooth. The ASMA involved superimposition of the combined labial surface of all the anterior teeth on one side on the mirror image of the combined labial surface of the contralateral side. For each asymmetry, the discrepancies in the form of 3D Euclidean distances were calculated and statistically evaluated by the Kruskal-Wallis test (p = 0.05). RESULTS: At the TMA level, the digital wax-up models had significantly less asymmetry (p < 0.00) than the pre-treatment and conventional wax-up models. The pre-treatment and conventional wax-up models had similar asymmetry (p = 0.35). However, at the ASMA level, the difference between the models was insignificant (p > 0.05). CONCLUSION: In this study, the single tooth symmetry had improved after the digital wax-up. However, the conventional wax-up had a minimal impact on single tooth symmetry. ASMA was minimally affected by the two wax-ups.