Digital evaluation of marginal and internal fit of single‐crown fixed dental prostheses

Abstract

The present study used a new, digitized version of the impression replica technique, namely the dual‐scan technique, to evaluate the adaptation of single‐crown fixed dental prostheses (FDPs). Scans of the bare master model and of the master model with a silicone layer representing the cement layer were superimposed and analyzed using designated software. Single crowns produced using the lost‐wax metal casting technique were included. The cement space of the band width, 0.5–1.0 mm from the preparation margin (marginal fit), was smallest for crowns made from laser‐sintered cobalt‐chromium. The internal fit in both mesial‐distal and buccal‐palatal directions was statistically significantly better for crowns made using the conventional lost‐wax metal casting technique than for crowns produced using computer‐aided design/computer‐aided manufacturing (CAD/CAM). Fixed dental prostheses produced by milled cobalt‐chromium had the loosest internal fit. The results agree with those of our previous study of the same test specimens, in which the triple‐scan method was used, and imply that the dual‐scan method is well suited for adaptation studies.

Evaluation of marginal adaptation in three-unit frameworks fabricated with conventional and powder-free digital impression techniques

“…For the control group, the single-unit frameworks were produced with the lost wax metal casting technique with cobalt-chromium by using conventional impression techniques. According to the study results, the researchers reported that laser sintered cobalt-chromium crowns fabricated with the digital impressions technique with the help of Trios intraoral scanner showed significantly better marginal fit than all other digital technique groups and the control group using the conventional technique 8. Similarly, in the present study, the measured marginal fit values of the restorations produced with conventional impression was found to be greater than those produced by the digital impression.…”

“…Digital impression systems were developed as an alternative to conventional impression systems 789. However, scanning with powder, low-resolution, and insufficient computing power caused restorations with unacceptable values of marginal misfit 10.…”

Adaptability Evaluation of Metal-Ceramic Crowns Obtained by Additive and Subtractive Technologies

“…These images are superimposed and analyzed with specific software. This is a good alternative for traditional silicon replica but is more expensive because it requires an intra-oral scanner for clinical use [18,19]. The best evaluating method for crown adaptation is the invasive method, well known but with some critical issues which limit its applicability.…”

“…In the case of fixed prosthodontics, the internal and marginal gaps are the essential factors to determine the long-term success of the restoration. This is why the prostheses adaptation is a subject that is still of interest for the prosthodontist and researchers [19,24,25].…”

Stereomicroscopic evaluation of marginal fit of E.Max press and E.Max computer-aided design and computer-assisted manufacturing lithium disilicate ceramic crowns: An in vitro study

“…[217] Several methods, ranging from stereomicroscopy, scanning electron microscopy, optical microscopy, and micro-computed tomography were utilized to evaluate the marginal fit of the restorations. [18192021]…”