Assistant Lecturer of Fixed Prosthodontics, Department of Conservative Dentistry, Alexandria University, Alexandria, Egypt.
Professor of Fixed Prosthodontics, Department of Conservative Dentistry, Alexandria University, Alexandria, Egypt.
J Prosthet Dent. 2023 Jul;130(1):28-34. doi: 10.1016/j.prosdent.2021.08.025. Epub 2021 Oct 23.
Available studies comparing fit accuracy of zirconia fixed partial dentures (FPDs) fabricated from conventional impressions and digital scans provide contradictory results. In addition, studies have been heterogeneous and of a limited number to provide conclusive evidence.
The purpose of this systematic review and meta-analysis was to compare the marginal and intaglio fit of tooth-supported zirconia FPDs fabricated from conventional impressions and digital scans and to investigate the effect of different variables on the fit results.
An electronic search was performed on the National Library of Medicine (NLM), Cochrane Central Register of Controlled Trials, and Scopus databases. In addition, a manual search was carried out. Studies comparing the fit of tooth-supported zirconia FPDs fabricated from conventional impressions and digital scans and reporting sufficient data for qualitative and quantitative analysis were included. Standard mean differences (SMDs) and 95% confidence intervals (CI) were calculated for meta-analysis. Subgroup analysis was performed to study the effect of variables including restoration form (monolithic or framework), units number, intraoral scanner (IOS) type, conventional impression material, spacer thickness, and abutments region.
The initial search resulted in a total of 608 articles. Nine articles were included in the analysis (1 clinical and 8 in vitro) evaluating 118 restorations. Digital scan displayed significantly better marginal fit (P<.001; SMD: -0.68; 95% CI: -0.92, -0.09) and intaglio fit (P=.020; SMD: -0.51; 95% CI: -0.94, -0.42). Test for subgroup difference showed a significant influence of only impression material type (P=.008) and units number (P=.030) on marginal fit. Digital scan showed significantly better marginal accuracy for 3-unit FPDs than 4-unit FPDs (P<.001; SMD: -1.02; 95% CI: -1.41, -0.63). In addition, digital scanning had significantly better marginal fit with polyvinyl siloxane than polyether (P<.001; SMD: -0.98; 95% CI: -1.32, -0.64). A cement spacer ≤50 μm improved both marginal and intaglio fit in the digital group. The TRIOS scanner resulted in the best performance in the digital group for marginal fit.
Digital scanning provides significantly better marginal and intaglio fit than conventional impression making for fabricating zirconia FPDs up to 4 units, either in monolithic form or frameworks and at any region of the arch. However, further clinical studies are recommended to obtain more substantial results.
比较传统印模和数字扫描制作的氧化锆固定局部义齿（FPD）拟合精度的现有研究结果相互矛盾。此外，研究结果存在异质性且数量有限，无法提供确凿的证据。
本系统评价和荟萃分析的目的是比较传统印模和数字扫描制作的牙支持氧化锆 FPD 的边缘和凹面拟合，并研究不同变量对拟合结果的影响。
在国家医学图书馆（NLM）、考科兰中心对照试验注册库和 Scopus 数据库上进行电子检索。此外，还进行了手动搜索。纳入了比较传统印模和数字扫描制作的牙支持氧化锆 FPD 拟合的研究，并报告了定性和定量分析所需的足够数据。计算了标准化均数差值（SMD）和 95%置信区间（CI）进行荟萃分析。进行了亚组分析，以研究包括修复体形式（整体或支架）、单位数量、口内扫描仪（IOS）类型、传统印模材料、间隔厚度和基牙区域在内的变量的影响。
最初的搜索共产生了 608 篇文章。9 篇文章被纳入分析（1 篇临床研究和 8 篇体外研究），共评估了 118 个修复体。数字扫描显示出明显更好的边缘拟合（P<.001；SMD：-0.68；95%CI：-0.92，-0.09）和凹面拟合（P=.020；SMD：-0.51；95%CI：-0.94，-0.42）。亚组差异检验表明，仅印模材料类型（P=.008）和单位数量（P=.030）对边缘拟合有显著影响。数字扫描在 3 单位 FPD 上的边缘精度明显优于 4 单位 FPD（P<.001；SMD：-1.02；95%CI：-1.41，-0.63）。此外，与聚醚相比，数字扫描用聚硅氧烷具有更好的边缘拟合（P<.001；SMD：-0.98；95%CI：-1.32，-0.64）。厚度≤50μm 的水泥间隔物可改善数字组的边缘和凹面贴合。Trios 扫描仪在数字组中对边缘拟合的表现最佳。
对于制作氧化锆 FPD，数字扫描在制作最多 4 个单位的整体或支架形式的义齿，以及在任何牙弓区域，都提供了比传统印模更好的边缘和凹面贴合精度。然而，建议进行更多的临床研究以获得更实质性的结果。
