A meta-analysis of the accuracy of different measuring techniques to evaluate the marginal and internal gap of a fixed dental prosthesis: The American Academy of Fixed Prosthodontics, Research in Fixed Prosthodontics Committee

Abstract

Statement of problem

Marginal gaps and the internal adaptation of a fixed dental prosthesis are important parameters related to a successful clinical outcome. Several methods have been used to measure these 2 parameters. In addition to conventional analog methods, digital methods have recently been developed. Nevertheless, statistical comparisons of these different approaches are scarce.

Purpose

The purpose of this study was to evaluate the results of the various measuring methods reported in the current literature and compare their results.

Material and methods

An electronic literature search comprising articles published from January 1990 to June 2023was conducted through the MEDLINE (PubMed) and Web of Science databases. After a quality assessment screening, 17 articles were identified for inclusion in the meta-analysis. Data were used for the random-effects model, forest plots were drawn, and significance tests were conducted in the meta-analysis software program of the Cochrane Collaboration (RevManv5.3.5). Additionally, heterogeneity tests and a risk of bias analysis were performed.

Results

In the general comparison of conventional and digital methods, the data did not show significant differences, and the results presented low homogeneity. When the cross-sectional method (CSM) was compared under a scanning electron microscope with the silicone replica Geomagic software program (SRG) method, CSM recorded significantly smaller gap values than SRG and presented high homogeneity. Meanwhile, in the comparison of CSM with the silicone replica technique (SRT) and the triple scan method (TSM), CSM recorded larger gap values than SRT and TSM, and the data did not show a significant difference. All of these results presented low homogeneity.

Conclusions

A comparison of most techniques revealed no significant differences in the internal and marginal gaps, except for SRG, which recorded significantly smaller gaps than CSM. However, the conclusions of these findings are limited because of concerns about bias and heterogeneity and because the found marginal gap data are just one way to assess the consistency and reliability of each method.