Comparison of intraoral adjustment and trueness of zirconia crowns fabricated by digital light processing 3D printing at different build angles : A clinical study = 디지털 광처리(DLP) 3D 프린팅의 출력각도가 지르코니아 크라운의 제작 정밀도와 구강 내 조정에 미치는 영향 : 임상 비교 연구

다국어 초록 (Multilingual Abstract)

Purpose: The purpose of this study was to evaluate the effect of build angle (0°, 45°, and 90°) in digital light processing (DLP) 3D printing on the trueness and chairside adjustment of zirconia crowns, and to compare these outcomes with those of milled crowns in a within- patient design. Material and Methods: Ten patients requiring a single zirconia crown were enrolled. For each patient, one crown was fabricated by milling using a 5-axis machine (Motion 2; Amann Girrbach, Koblach, Austria) and a zirconia block (DMAX; DMAX, Seoul, Republic of Korea). In addition, three crowns were fabricated using a DLP 3D printer (TD6; 3D CONTROLS, Busan, Republic of Korea) with zirconia slurry (Cera-P; 3D CONTROLS) at build angles of 0°, 45°, and 90°, respectively (n = 40). Cement space was set at 50 µm. Crowns were scanned before try-in using an intraoral scanner (i700; Medit, Seoul, Republic of Korea) and superimposed onto the CAD design; trueness was calculated as the root mean square (RMS, µm) of surface deviations. During insertion, intaglio fit was checked with silicone indicator (Fit Checker; GC, Tokyo, Japan) and occlusion was adjusted with articulating paper (Bite-Check; Bausch, Cologne, Germany) under maximal intercuspal and eccentric contacts. Pre- and post- adjustment scans were superimposed to quantify occlusal and intaglio adjustment (RMS values). Data were analyzed by one-way ANOVA with Tukey’s post hoc test (α = 0.05). Results: Trueness was significantly higher in the 0° printed group compared with the 90° printed and milled groups, while the difference between 0° and 45° was not significant (p = 0.055). Occlusal adjustment was smallest for the 0° group and largest for milling (0° group 25.7 ± 7.8 µm; 45° group 42.5 ± 23.1 µm; 90° group 46.8 ± 38.9 µm; milling group 63.8 ± 15.0 µm; p = 0.012). Intaglio adjustment was also lower for printed crowns than for milled crowns (milling group 56.5 ± 26.2 µm; 0° group 20.6 ± 9.8 µm; 90° group 21.2 ± 7.0 µm; 45° group 25.4 ± 10.7 µm; p < 0.001). Conclusions: DLP 3D printing produced zirconia crowns with superior trueness and reduced chairside adjustment compared with milling. Printing at a 0° build angle further improved accuracy and minimized clinical adjustment requirements.

목차 (Table of Contents)

• Ⅰ. Introduction 1
• Ⅱ. Materials and methods 4
• Ⅲ. Results 19
• Ⅳ. Discussion 30
• Ⅴ. Conclusion 38
• References 39
• Abstract in Korean 45