Ung Stephanie, Veerasamy Arthi, Jansen van Vuuren Wendy-Ann, Bennani Vincent
Sir John Walsh Research Institute, University of Otago, Dunedin, New Zealand.
Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.
Int J Dent. 2025 Sep 15;2025:7599339. doi: 10.1155/ijod/7599339. eCollection 2025.
Bonded onlay preparations provide minimal guidance during cementation, which may compromise seating accuracy and increase marginal and internal discrepancies, potentially affecting restoration longevity. This study aims to assess whether a modified preparation (MP) design improves onlay positioning during cementation to enhance marginal and internal fit. The conventional preparation (CP) design was prepared on a typodont tooth, scanned, and replicated ( = 20). A cross-shaped groove was added to the prepared typodont tooth to create the MP design, then scanned and replicated ( = 20). For both groups, a restoration was designed using computer-aided design (CAD) and computer-aided manufacturing (CAM). Each onlay was three-dimensionally (3D) printed, assessed for fit, and then bonded onto the replicas. Ten specimens from each group were sectioned horizontally and 10 vertically. Absolute marginal discrepancy (AMD) and internal cement thickness (ICT) were measured on the horizontally and vertically sectioned specimens under a stereomicroscope. Data were analyzed using the Mann-Whitney test ( = 0.05). The MP showed a statistically significant lower mean AMD than the CP at the palatal (=0.035) and buccal (=0.006) sites. However, there was no statistically significant difference at the mesial site (=0.193). The CP had a statistically significant lower ICT than the MP in the vertical section (=0.009), but the difference in the horizontal section was not statistically significant (=0.121). The MP improved AMD compared to the CP at buccal and palatal sites, but increased ICT in the vertical section. The MP design showed that a minor modification to the conventional bonded onlay preparation design improved AMD but increased ICT. These findings guide clinicians in selecting optimal designs to improve restoration adaptation and longevity.
粘结式高嵌体预备在粘结过程中提供的引导极少，这可能会影响就位精度，增加边缘和内部差异，从而可能影响修复体的使用寿命。本研究旨在评估一种改良预备（MP）设计是否能在粘结过程中改善高嵌体的就位情况，以提高边缘和内部贴合度。在一个模型牙上制备传统预备（CP）设计，进行扫描并复制（n = 20）。在制备好的模型牙上添加一个十字形凹槽以创建MP设计，然后进行扫描并复制（n = 20）。对于两组，均使用计算机辅助设计（CAD）和计算机辅助制造（CAM）设计修复体。每个高嵌体采用三维（3D）打印，评估其贴合度，然后粘结到复制体上。每组取10个标本进行水平切片，10个进行垂直切片。在立体显微镜下对水平和垂直切片的标本测量绝对边缘差异（AMD）和内部粘结剂厚度（ICT）。使用曼-惠特尼检验分析数据（α = 0.05）。MP在腭侧（P = 0.035）和颊侧（P = 0.006）部位的平均AMD显著低于CP。然而，在近中部位（P = 0.193）没有统计学显著差异。在垂直切片中，CP的ICT显著低于MP（P = 0.009），但在水平切片中的差异无统计学意义（P = 0.121）。与CP相比，MP在颊侧和腭侧部位改善了AMD，但在垂直切片中增加了ICT。MP设计表明，对传统粘结式高嵌体预备设计进行微小修改可改善AMD，但增加了ICT。这些发现为临床医生选择最佳设计以提高修复体适应性和使用寿命提供了指导。
