earticle

영어

Purpose: This study aimed to evaluate the accuracy of custom zirconia implant abutments fabricated using two different five-axis milling machines under conventional and speed sintering conditions. Methods: Custom abutments were designed with a computer-aided design (CAD)/computer- aided manufacturing system and manufactured using two five-axis milling machines. All specimens underwent either conventional or speed sintering, followed by three-dimensional scanning and superimposition with reference CAD data. Accuracy was analyzed by root mean square (RMS) values and color-difference maps, and significance was tested using two-way analysis of variance and Bonferroni post hoc analysis. Results: The three-dimensional accuracy of customized zirconia abutments fabricated by two five-axis milling machines (MA and MB) under conventional (C) and speed (S) sintering was assessed. Abutments from MB (MBC and MBS) showed significantly lower RMS values than those from MA (MAC and MAS), indicating higher accuracy (p<0.001). A significant interaction between the milling machine and sintering condition was found in marginal trueness and precision (p<0.05). MBC showed higher marginal accuracy than MAC under C, and MBS outperformed MAS under S. Conclusion: Milling machines significantly influenced the dimensional accuracy of customized zirconia abutments, and sintering conditions affected marginal precision through their interaction with milling. Machine B demonstrated superior overall accuracy, and speed sintering resulted in consistent and clinically acceptable results. These findings underscore the importance of optimizing milling performance and sintering parameters to achieve high fabrication accuracy.