Department of Crown and Bridge Prosthodontics, School of Life Dentistry at Niigata, The Nippon Dental University, Niigata, Japan.
Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany.
Odontology. 2021 Jul;109(3):719-728. doi: 10.1007/s10266-021-00595-3. Epub 2021 Mar 23.
The purpose of this study is to investigate the effects of porcelain veneering methods on the marginal and internal fit of a three-unit zirconia framework. A zirconia master model, in which the lower-left second premolar and the second left molar were used as the abutment, was obtained using an intraoral scanner. Based on the data, three-unit zirconia frameworks for fabricating all-ceramic bridges were designed and milled (FW group). Two types of all-ceramic bridge were fabricated by veneering porcelain onto these frameworks using the press-over technique (P group) and the layering technique (L group). The replica technique was used to measure the gap size between the abutments and the bridges. Measurements were taken in the marginal opening area (MO), chamfer area (CH), axial area (AX), and occlusal area (OC). Statistical analysis was performed using the Mann-Whitney U-test. There was no significant difference in MO and CH between the P and L groups. However, in AX, the L group had a significantly larger gap size than that of the P group (p = 0.003). In addition, compared with the FW group, the P group showed a significantly larger gap size in MO (p < 0.000), CH (p = 0.008), and OC (p < 0.000). These results indicate that the gap size increased after porcelain veneering using the press-over and layering techniques. In addition, the all-ceramic bridges fabricated using the press-over and layering techniques had approximately equal gap sizes in MO.
本研究旨在探讨瓷贴面方法对三单位氧化锆框架的边缘和内部适合度的影响。通过口内扫描仪获得了以下颌左第二前磨牙和第二左磨牙为基牙的氧化锆主模型。基于这些数据，设计并加工了用于制作全瓷桥的三单位氧化锆框架（FW 组）。通过按压技术（P 组）和分层技术（L 组）将瓷贴面应用于这些框架上，制造了两种全瓷桥。使用复制技术测量基牙与桥体之间的间隙大小。在边缘开口区（MO）、倒角区（CH）、轴区（AX）和咬合区（OC）进行测量。采用 Mann-Whitney U 检验进行统计分析。在 MO 和 CH 区域，P 组和 L 组之间没有显著差异。然而，在 AX 区域，L 组的间隙尺寸明显大于 P 组（p=0.003）。此外，与 FW 组相比，P 组在 MO（p<0.000）、CH（p=0.008）和 OC（p<0.000）区域的间隙尺寸明显更大。这些结果表明，使用按压和分层技术进行瓷贴面后，间隙尺寸增加。此外，使用按压和分层技术制造的全瓷桥在 MO 区域具有大致相等的间隙尺寸。
