LAUSR

PURPOSE To compare the accuracy of the tooth morphology fusion (TMF) digital technique and customized impression transfer coping (conventional) technique when transferring the morphology of a provisional crown to a definitive screw-retained implant-supported crown. METHODS Six cases of partial edentulism (one anterior and five posterior) treated with oral implant placement in our clinic for the loss of three or fewer teeth in the maxilla or mandible between April 2017 and September 2018 were included. After implant placement and re-entry surgery, provisional restorations were made and adjusted to obtain the ideal morphology. Two definitive restorations were constructed by transferring the complete morphology of the provisional restorations, including the subgingival contour, using the TMF digital and conventional techniques. Three sets of surface morphological data were obtained using a desktop scanner. The three-dimensional total discrepancy volume (TDV) between the provisional restoration (reference) and the two definitive restorations was digitally measured by overlapping the surface data of the stone cast using the Boolean operation. Each TDV ratio (%) was calculated by dividing the TDV by the volume of provisional restoration. The median TDV ratios for TMF and conventional techniques were compared using the Wilcoxon signed-rank test. RESULTS The median TDV ratio between provisional and definitive restorations constructed using the TMF digital technique (8.05%) was significantly lower than that obtained using the conventional technique (13.56%, P < 0.05). CONCLUSIONS In this preliminary intervention study, the TMF digital technique was more accurate than the conventional technique for the transfer of morphology from provisional to definitive prosthesis.