Abstract
Statement of problem: Considerable variability exists in the measurement methods for assessing the fit of screw-retained implant-supported fixed partial dentures (FPDs) because of the lack of standardization. Scientific evidence comparing the precision and reliability of various measurement methods remains limited.
Purpose: The purpose of this systematic review of in vitro studies was to evaluate the precision of various measurement methods for assessing the fit of screw-retained implant-supported FPDs.
Material and methods: An electronic search was conducted in MEDLINE (via Ovid), Embase (via Ovid), Scopus, and Web of Science for articles published between January 2020 and August 2025, with PubMed screened additionally for ahead-of-print records not yet indexed in MEDLINE. Eligible articles were selected based on predefined inclusion and exclusion criteria, and relevant data were extracted. The Quality Assessment Tool For In Vitro Studies (QUIN Tool) was used to evaluate the methodological quality of the included studies. The coefficient of variation (CV) was calculated to evaluate the precision of each measurement method.
Results: After screening and applying the eligibility criteria, 13 of the initial 1851 records were identified for inclusion. Quality assessment showed that 5 studies had a low risk of bias and that 8 had a medium risk. All included studies evaluated the marginal fit of FPDs, with none assessing internal fit. Across these studies, 6 measurement techniques and 2 test conditions were used. Under the 1-screw test (OST), radiographic evaluation showed the lowest CV (13.7%), indicating the highest precision, while the profile projection exhibited the greatest variability (70.7%). Under the all-screws test (AST), optical microscopy demonstrated the greatest repeatability with a CV of 20.5%, closely followed by 3-dimensional confocal laser scanning microscopy (3D CLSM) at 23.4%.
Conclusions: Most techniques showed greater repeatability under OST than AST. Radiographic evaluation was the most precise method under OST, while optical microscopy demonstrated the highest precision under AST. These findings offer valuable guidance for selecting measurement techniques to determine the fit accuracy of screw-retained implant-supported FPDs.