Department of Dentistry and Oral Health, Aarhus University, Vennelyst Boulevard 9, DK-8000, Aarhus C, Denmark.
Clin Oral Investig. 2019 Nov;23(11):4043-4050. doi: 10.1007/s00784-019-02840-0. Epub 2019 Feb 22.
The aim of this prospective in vivo study was to evaluate the accuracy of the marginal and internal fit of crowns based on conventional impression (CI) or intraoral scan (IOS) in a randomised, split-mouth set-up.
Nineteen patients needing full coverage crowns, fitting a split-mouth design, were provided with two lithium disilicate crowns: one based on a CI and one based on an IOS. The marginal and internal accuracy of the crowns were assessed with the replica technique and clinically using a modified California Dental Association (CDA) quality evaluation system.
At the preparation margin, the median gap was 60 μm for IOS and 78 μm for CI. For the other points, the median gap ranged from 91 to 159 μm for IOS and 109 to 181 μm for CI. The accuracy of the IOS was statistically significantly better at all point except at the cusp tip. All crowns where rated R or S at both the 6- and 12-month follow-up appointments. The results for the clinical evaluation with CDA for marginal integrity showed no statistically significant difference between the two impression methods at both the 6- and 12-month evaluations.
Crowns based on IOS show statistically significantly better marginal and internal adaptation before cementation compared to conventional impression. However, the clinical evaluation showed similar marginal adaptation.
Crowns based on a fully digital workflow can provide clinically acceptable marginal adaptation, comparable to crowns based on CI.
本前瞻性体内研究的目的是评估基于传统印模（CI）或口内扫描（IOS）的冠边缘和内部适合度的准确性，采用随机、分口设计。
19 名需要全冠覆盖、符合分口设计的患者，提供了两种锂硅玻璃陶瓷冠：一种基于 CI，一种基于 IOS。采用复制技术和改良加利福尼亚牙科学会（CDA）质量评估系统临床评估冠的边缘和内部准确性。
在预备边缘处，IOS 的中位数间隙为 60μm，CI 的中位数间隙为 78μm。对于其他点，IOS 的中位数间隙范围为 91μm 至 159μm，CI 的中位数间隙范围为 109μm 至 181μm。除了牙尖点外，IOS 的准确性在所有点都具有统计学意义上的优势。所有冠在 6 个月和 12 个月的随访时均被评为 R 或 S。在 6 个月和 12 个月的评估中，CDA 对边缘完整性的临床评估结果表明，两种印模方法之间没有统计学上的显著差异。
在粘结前，基于 IOS 的冠在边缘和内部适应性方面具有统计学意义上的优势，优于传统印模。然而，临床评估显示出类似的边缘适应性。
基于完全数字化工作流程的冠可以提供临床可接受的边缘适应性，与基于 CI 的冠相当。
