In vitro validation of Digital Image Analysis Sequence (DIAS) for the assessment of the marginal fit of cement-retained implant-supported experimental crowns (original) (raw)
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Digital evaluation of marginal and internal fit of single‐crown fixed dental prostheses
European Journal of Oral Sciences, 2018
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 prev...
Marginal accuracy of different CAD/CAM monolithic crowns cemented on implant abutments
Egyptian Dental Journal, 2021
Computer-aided design/computer-assisted manufacturing (CAD/CAM) process allows the chairside fabrication of implant-supported prostheses with satisfactory marginal gap. (1,2) There are several types of ceramics used in posterior fixed restorations with similar survival rates to those of conventional restorative materials.
Materiale Plastice
The objective of this in-vitro study was to compare if there are any differences in the marginal fit of crowns fabricated by CAD/CAM technique. We used three different types of materials (two types of polymethylmetacrylate (PMMA) provided by two different manufacturers and one type of hybrid ceramic) and three different types of impressions: intraoral scanning, model scanning and conventional impression scanning. The crowns were subsequently measured with an electronic microscope at 1000X. Our results showed better results for the hybrid ceramic. The differences between the PMMA were not significant. There were no statistic differences with the ANOVA analysis between the scanning methods. Best combination in terms of marginal fit was found with hybrid ceramic and intraoral scanning.
2018
Statement of the Problem: The emergence of different types of scanners and competition in the market raise a question on the influence of these different scanners on the margin accuracy and internal fit of the CAD/CAM generated all-ceramic crowns. Keywords: Margin Accuracy; Internal Fit; CAD/CAM; Implant-Abutment; Omnicam; Cone Beam Material and Methods: The prefabricated titanium implant abutments used in this study were selected representing upper first premolar. Three implant abutments were divided into 3 groups as follows: Group 1: consisted of 5 scans with the Cerec Bluecam. Group 2: consisted of 5 scans with the Cerec Omnicam. Group 3: consisted of 5 scans with the Cerec Ineos camera. The vertical marginal gap distance between the crown and the implant abutment was measured using stereomicroscope connected to computer and digital camera. Measurements were made at thirty points for each surface of the crown. A rubber base replica of the space between the crown and the implant abutments was made for each tested specimen to assess its internal fit using the stereomicroscope. The recorded data were collected, tabulated and statistically analyzed. Result: It was found that the mean and standard deviation values of marginal accuracy data were 130 ± 3 μm, 320 ± 3 μm and 100 ± 2 μm with Blue cam, Ineos and Omnicam, respectively. The mean and standard deviation values of internal fit data were 420 ± 21 μm, 260 ± 16 μm and 290 ± 15 μm with 3D Blue Cam, Ineos and Omnicam respectively. Result of obtained from Cone beam C.T. revealed that the mean and standard deviation values of internal fit data were 450 ± 26 μm, 400 ± 23 μm and 360 ± 22 μm with 3D Blue Cam, Ineos and Omnicam respectively (P-value < 0.05). Conclusion: Within the limitations of this study, the following conclusions could be drawn: Digitizing techniques (Bluecam, Omnicam and Ineos) had a great influence on the marginal adaptation and internal fit of all-ceramic crowns placed on implant-abutment. Bluecam are the most appropriate digitizing technique in obtaining the best marginal adaptation compared to Ineos. Marginal accuracy and internal fit values recorded in the tested groups lied within the range of clinical “acceptance (100 - 200) μm. Omnicam scanner is not an appropriate digitizing technique in obtaining the best internal fit compared to bluecam and Ineos.
The Journal of Prosthetic Dentistry, 2014
Statement of problem. The development of computer-aided design/computer-aided manufacturing technology has enabled the fabrication of implant-retained restorations. However, information on the marginal and axial accuracy of restorations fabricated by different digitizing techniques with different antirotational abutment features is not sufficient. Purpose. The purpose of this in vitro study was to evaluate the influence of digitizing techniques on the fit of implant-retained crowns with 2 antirotational features. Material and Methods. An experimental working cast housing a tissue-level dental implant was created. Resin-retained abutments with different antirotational features were connected to the implant. Optical impressions of 2 abutment types were obtained separately with 1 chairside and 2 laboratory approaches. Alumina silicate restorations were milled from chairside optical impressions, and ceramic oxide cores were milled from laboratory optical impressions. Restoration fit was evaluated from axial sections of restorations with silicone materials representing the marginal and axial gaps. Axial and marginal fits were measured on digital photographs of the sectioned specimens with a computer program. Two-way ANOVA was used to compare differences between abutments with 2 different antirotational features and digitizing techniques separately for the marginal and axial fits of single implant-retained crowns. A post hoc least significant difference test was used to compare digitizing techniques (a¼.05). Results. Significant differences in the marginal fit of single-implant-retained crowns were found among digitizing techniques (P¼.011) and between antirotational features (P<.001). No significant difference in the axial fit of single-implant-retained crowns was found among digitizing techniques (P¼.905) or between antirotational features (P¼.075). Conclusions. Within the limitations of this in vitro study, the marginal fit of single-implant-retained crowns was affected by antirotational abutment features. Furthermore, digitizing techniques were found to play an important role in the marginal fit of single-implant-retained restorations.
BioMed research international, 2018
To evaluate the influence of different manufacturing methods of single implant-supported metallic crowns on the internal and external marginal fit through computed microtomography. Forty external hexagon implants were divided into 4 groups ( = 8), according to the manufacturing method: GC, conventional casting; GI, induction casting; GP, plasma casting; and GCAD, CAD/CAM machining. The crowns were attached to the implants with insertion torque of 30 N·cm. The external (vertical and horizontal) marginal fit and internal fit were assessed through computed microtomography. Internal and external marginal fit data (m) were submitted to a one-way ANOVA and Tukey's test ( = .05). Qualitative evaluation of the images was conducted by using micro-CT. The statistical analysis revealed no significant difference between the groups for vertical misfit ( = 0.721). There was no significant difference ( > 0.05) for the internal and horizontal marginal misfit in the groups GC, GI, and GP, but...
Journal of Evolution of Medical and Dental Sciences, 2019
BACKGROUND Although the metal-ceramic system is still widely used to fabricate crowns and fixed partial dentures, and is considered as the standard treatment in dentistry, aesthetic concerns have stimulated the development of new dental tooth-coloured systems such as PEEK. So, the present study was planned to check the marginal fit accuracies of conventional Porcelain Fused to Metal (PFM) crowns and Polyether Ether Ketone (PEEK) crowns. METHODS Based on the inclusion and exclusion criteria, sample size of 80 patients was considered. Out of 80 patients, 40 patients (Group I) received PFM crowns and 40 patients received PEEK (Group II) crowns. The marginal fit accuracy of crowns was checked using stereomicroscope. CBCT of the same patient with the crown was made to validate the readings obtained using stereomicroscope. RESULTS Data was analysed with the SPSS (Statistical Package for Social Sciences) version 17. Comparison of the two groups for marginal gap was done with unpaired 't' Test. For all the above tests, p value is considered statistically significant when it was ≤0.05. Four points were considered to measure the marginal gaps i.e., MB (Mesiobuccal), ML (Mesiolingual), DB (Distobuccal), DL (Distolingual). The highest marginal gap in the group I was at Mesiobuccal (MB) point i.e. 120.280000 microns and lowest marginal gap was at Distolingual (DL) point i.e. 110.127050 microns. It can be noted from CBCT that the marginal gap present in PFM crown is much greater than the PEEK crown. CONCLUSIONS Comparing the marginal fit accuracy between PFM and PEEK crowns based on the stereomicroscope readings, the marginal fit accuracy in PEEK crowns were much higher than the PFM crowns.
Journal of Prosthodontic Research
Purpose: A digital image correlation (DIC) method for full-field surface strain measurement was used to analyze the effect of two veneering materials for implant supported crowns on the strain distribution within the surrounding bone. Methods: An epoxy resin model of a bone block was made by housing acrylic resin replicas of a mandibular first premolar and second molar together with threaded implants replacing the second premolar and first molar. Porcelain-veneered (G1 and G3) and resin-veneered (G2 and G4) screw-retained splinted crowns were fabricated and loaded with (G1 and G2) and without (G3 and G4) the presence of the second molar replica. A 2-dimensional DIC measuring system was used to record surface deformation of the bone block model at a frequency of 1.0 Hz during application of a 250-N load. Results: Maximum compressive strains (e XX , %) were found for the following regions: between molars, ). The magnitude of strains in the simulated bone block with the resin-veneered crowns was lower than that with porcelain-veneered crowns, irrespective of the presence or absence of the second molar. Conclusions: The softer resin veneer helped to spread the load more evenly amongst the supporting teeth and implants, thus reducing the strains in the simulant bone block. Conversely, using the harder porcelain veneer resulted in the load being concentrated within one or two teeth or implants, thus leading to higher strain values in the bone block.