Marginal Accuracy of Lithium Disilicate Full‐Coverage Single Crowns Made by Direct and Indirect Digital or Conventional Workflows: A Systematic Review and Meta‐Analysis

Abstract

Purpose Several studies have compared digital intraoral scanners and conventional impressions. The accuracy of these two methods in terms of marginal accuracy of lithium disilicate crowns is not well‐established, yet. The purpose of this study was to systematically review available publications on marginal fit of single‐unit, full‐coverage, tooth‐supported lithium disilicate restorations. Methods Pubmed, Web of Science, Cochrane, EMBASE, and Scopus were electronically searched along with a manual search. After critical appraisal, data from selected studies were extracted and mean marginal difference with a 95% confidence interval was calculated. Meta‐analysis of the collected data was conducted using STATA software. Results The meta‐analysis revealed similar marginal gap values in intraoral scanners with conventional groups (p>0.05) and in intraoral scanners with extraoral canners (p>0.05). Conclusion No significant difference was seen between digital and conventional impressions or intra‐ and extraoral scanners for marginal accuracy of lithium disilicate crowns.

A guide for maximizing the accuracy of intraoral digital scans. Part 1: Operator factors

“…16,[19][20][21] Complete digital workflows for fabricating tooth-and implantsupported crowns and short span fixed dental prostheses obtain similar marginal and internal discrepancies compared with conventional methods. [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] The challenge today remains to incorporate IOSs into complete digital workflows for fabricating complete dentures 29 and Kennedy Class I and II removable partial dentures. 30 Published studies have shown that intraoral digital scans can accurately digitized edentulous areas with firm attached tissue and mucosa, but capturing areas with mobile tissue by using an IOS is challenging, regardless of the scanning technology and system elected.…”

“…Complete digital workflows for fabricating tooth‐ and implant‐supported crowns and short span fixed dental prostheses obtain similar marginal and internal discrepancies compared with conventional methods 21–35 . The challenge today remains to incorporate IOSs into complete digital workflows for fabricating complete dentures 29 and Kennedy Class I and II removable partial dentures 30 .…”

“…However, research approaches should be distinguished between both methodologies. In laboratory studies, the ground truth or the reference model used to calculate accuracy values is known 16–36 . This means that the dimensions of the reference model are obtained by using the most accurate methods available today such as coordinate measurement machine (CMM) or an industrial scanner.…”

“…Scanning accuracy discrepancies have been reported in the dental literature among the different scanning technologies and systems available based on the different clinical applications 16–36 . Independent of the scanning technology and IOSs system, IOSs provide a reliable digital impression alternative for acquiring virtual diagnostic casts with similar accuracy when compared with conventional impression methods 16–21,31 .…”

“…This means that the dimensions of the reference model are obtained by using the most accurate methods available today such as coordinate measurement machine (CMM) or an industrial scanner. On the other hand, in clinical conditions, the ground truth or the real dimensions of the patient's intraoral tissues being digitized are not known, and the reference model is obtained by using conventional techniques such as diagnostic stone casts 16–36 …”