Accuracy and Reliability of Methods to Measure Marginal Adaptation of Crowns and FDPs: A Literature Review

Abstract

There was a substantial lack of consensus relating to marginal adaptation of various crown systems due to differences in testing methods and experimental protocols employed. Direct view technique was the most commonly used method of reproducible results. Also, conducting an experimental set-up of testing a minimum of 30 specimens at 50 measurements per specimen should produce reliable results. Additionally, using a combination of two measurement methods can be useful in verification of results.

Die spacer thickness reproduction for central incisor crown fabrication with combined computer-aided design and 3D printing technology: An in vitro study

“…Five measurements were made to create an average value at each point, leading to a total of 50 measurements (5×2×5) per die. 37 Overall, 4000 measurements (50 measurements×80 specimens) were obtained for the entire study. The internal gap image was obtained with an inverted bright field metallurgical microscope at ×100 magnification (Metallograph/Microscope; Leco/Olympus).…”

“…Errors may have occurred in any step of the process chain, starting from impression making and the generation of die-stone models to the scanning process and printing process. Also, only 50 measurements per specimen were obtained in this study, 37 and the measurements obtained were specific to this software/hardware combination (CAD and 3DPT). The results may not be applicable to other software/hardware combinations.…”

Ajuste marginal e interno de restaurações de cerâmica pura fabricadas em CAD / CAM: uma revisão da literatura

“…Given that factors as: prepared tooth design, localization and number of the maladjustment measure points, measurement technique, kind of resinous cement (if used), and method of restoration fabrication are directly related to marginal discrepancy value found. 38 Reported marginal adaptation was inside the acceptable clinical parameters, considering it as below 100 µm.…”

SEM evaluation of the precision of fit of CAD/CAM zirconia and metal-ceramic posterior crowns

“…Up to date, there is a lack of consensus relating to marginal adaptation of various crowns systems due to differences in testing methods and experimental protocols employed 27) . In the present study, marginal adaptation was evaluated by direct viewing with external and internal measurements and although various protocols have been proposed to analyze the marginal gap, no general guideline exists on how to perform gap measurements 9,15,[27][28][29] .…”

“…In the present study, marginal adaptation was evaluated by direct viewing with external and internal measurements and although various protocols have been proposed to analyze the marginal gap, no general guideline exists on how to perform gap measurements 9,15,[27][28][29] . Several direct and indirect methods are available for analyzing the marginal and internal adaptation of fixed prosthodontics restorations.…”