Aim: The purpose of the present systematic review and meta-analysis was to evaluate the marginal adaptation of single-unit full-coverage lithium disilicate fixed dental restorations fabricated with the conventional heat-pressed technique and the digital CAD/CAM workflow.
Materials and methods: The present study was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Α study research was conducted in Medline via PubMed and Cochrane Library databases together with a hand search of studies published until June 2022. The search terms combined suitable MeSH (Medical Subject Headings) terms together with free text words in single or multiple conjunctions. A modified methodological index was used to assess the risk of bias of the included studies. A random effects model was applied to pool the effect estimates, and further assessment of the heterogeneity across studies was conducted using the Q test and the I2 metric. All statistical analyses were performed with RStudio software, version 4.1.2, using the “meta” package.
Results: The electronic search and hand search identified 51 articles. Eighteen articles met the inclusion criteria and were included in the systematic review, 17 of which were in vitro studies and only 1 was an in vivo study. However, only 17 of the initial 18 articles could be included in the meta-analysis due to a lack of statistical data in one of the in vitro studies. Statistical analyses were conducted using the RStudio software program. Meta-analysis was performed with the random effects model (α = 0.05). No statistical difference was found between the two fabrication methods (P = 0.49).
Conclusions: Although the mean marginal adaptation of lithium disilicate single crowns was found to be better with the heat-pressed technique, there was no statistical significance with the CAD/CAM-fabricated restorations, and both resulted in a clinically acceptable result. Nonetheless, more clinical studies are needed for safer conclusions.