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The International Journal of... Sep 2023To evaluate the dimensional discrepancy between the diagnostic wax-up and the resulting mock-up.
PURPOSE
To evaluate the dimensional discrepancy between the diagnostic wax-up and the resulting mock-up.
MATERIAL AND METHODS
A maxillary model with misaligned teeth was scanned, and an initial cast was 3D printed. A total of 60 identical casts were 3D printed from the initial one after scanning. Based on a digital additive veneer wax-up on the six anterior teeth, 10 more casts were 3D printed. The specimens were allocated to seven groups (n = 10) as follows-group 1: transparent silicone matrix with a flowable light-cured composite resin; group 2: same as group 1 but with the addition of a prefabricated transparent tray; group 3: silicone impression putty (65 Shore A) and light-body silicone impression material with a dual-cured bisacryl resin; group 4: same as group 3 but without the light-body silicone; group 5: silicone laboratory putty (92 Shore A) with a dual-cured bisacryl resin; group 6: silicone laboratory putty (92 Shore A) with PMMA; group 7: wax-up casts (control). Scans from the mock-ups were coregistered, segmented, and superimposed with the scans from the wax-up. The difference between the mock-up and the wax-up was quantified by morphologic operations. Results were analyzed by Kruskal-Wallis test and Dunn post hoc test (P < .05).
RESULTS
All mock-ups were larger than the wax-up. Significant differences were found for every labial surface third. The incisal third was the least accurate third while the middle third the most accurate. The most accurate were groups 2 and 5, and the largest discrepancy was observed in group 6.
CONCLUSIONS
The analog mock-up differs dimensionally from the wax-up, regardless of the technique/materials used.
Topics: Dental Impression Materials; Silicones
PubMed: 37699185
DOI: 10.11607/ijp.7183 -
Journal of Applied Oral Science :... 2023The use of a fiber glass post (FGP) type and choice of FGP diameter to restore endodontically treated incisors without ferrule is controversial. This study evaluated...
OBJECTIVE
The use of a fiber glass post (FGP) type and choice of FGP diameter to restore endodontically treated incisors without ferrule is controversial. This study evaluated survival rate and failure mode of severely compromised central incisors without ferrule rehabilitated using resin-based composite (RBC) with or without FGP with different diameters.
METHODOLOGY
A total of 60 decoronated bovine incisors without a ferrule were endodontically treated and prepared for 1.4, 1.6, and 1.8 mm diameter FGPs (Whitepost System DC 0.5, Fit 0.4, and DCE 0.5; FGM). Half of the teeth received FGPs cemented using dual-cure resin cement (Allcem Core; FGM), the other half were filled using only bulk-fill RBC (OPUS Bulk Fill; FGM). The crowns were directly restored with RBC. The roots were embedded in polystyrene resin and the periodontal ligament was simulated with polyether impression material. Fatigue testing was conducted under 5 Hz cyclic loading at 30 degrees to the incisal edge, beginning at 50 N (5,000 cycles) as a warmup. After, the load was increased 100 N every 15,000 cycles until fracture occurred. All specimens were subjected to transillumination, micro-CT analysis, and digital radiography before and after fatigue testing. Fracture mode was classified according to severity and repair potential. Data were analyzed with Kaplan-Meier survival test and post hoc log-rank test (α=0.05) for pairwise comparisons.
RESULTS
Using FGP significantly increased the number of cycles to failure, irrespective of FGP diameters (p=0.001). The FGP diameters had no statistically significant effect on cycles to failure or failure mode.
CONCLUSION
Using FGP without ferrule improved survival rate of structurally severely compromised central incisors compared with rehabilitation without FGP. The diameter of the FGPs had no effect on the survival rate and failure mode.
Topics: Animals; Cattle; Post and Core Technique; Composite Resins; Tooth, Nonvital; Crowns; Dental Materials; Glass; Dental Stress Analysis; Tooth Fractures; Dental Restoration Failure
PubMed: 37909530
DOI: 10.1590/1678-7757-2023-0241 -
The Journal of Prosthetic Dentistry Sep 2023Obtaining a passive and well-adapted framework is challenging when intraoral scanning edentulous arches with multiple implants. The trueness of the printed casts is...
STATEMENT OF PROBLEM
Obtaining a passive and well-adapted framework is challenging when intraoral scanning edentulous arches with multiple implants. The trueness of the printed casts is unclear.
PURPOSE
The purpose of this clinical study was to evaluate the trueness of frameworks made from conventional and printed casts regarding clinical passivity and misfit.
MATERIAL AND METHODS
Ten participants with complete mandibular fixed implant-supported interim prostheses retained by 4 implants were included. Each participant had a conventional impression and a digital scan made. The digital scan was made using an innovative device. Both conventional and digital casts were made, and the virtual images were used for milling the digital framework in cobalt chromium alloy. All frameworks were evaluated for passivity and marginal vertical misfit with the single screw test, with 4 attempts consisting of the tightened screw position, a test with all screws tightened, and an interspersed tightening test. The Kruskal-Wallis test was used to evaluate the trueness of the tested device for framework construction through the single screw test on vertical marginal misfit in the conventional and printed groups (α=.008). The Friedman test was used to assess the effect of test type (α=.05), and the Wilcoxon test was used to identify group-to-group differences (α=.017).
RESULTS
The absence of space between the framework and the abutments and interferences during its placement, as well as good stability, were observed clinically. In laboratory analysis, greater framework misfits were observed in the printed group compared with the conventional group when the single screw test was applied. Comparing the 3 tests used, the greatest misfits were observed when the framework was screwed onto the printed cast.
CONCLUSIONS
The innovative device tested for the intraoral scanning of multiple implants had clinically acceptable accuracy for the construction of passive and adapted frameworks. The conventional cast was more accurate than the printed cast, with lower misfit values, in all tests.
PubMed: 37748995
DOI: 10.1016/j.prosdent.2023.07.039 -
Journal of Prosthodontics : Official... Dec 2023This review aims to provide a comprehensive summary of how much progress has been made in the field of virtual occlusal records (VOR) obtained with intraoral scanners... (Review)
Review
PURPOSE
This review aims to provide a comprehensive summary of how much progress has been made in the field of virtual occlusal records (VOR) obtained with intraoral scanners (IOSs), their accuracy, and what factors influence their accuracy.
MATERIALS AND METHODS
An electronic search was performed in MEDLINE via PubMed and Scopus databases in February 2023. Eligible articles were clinical or in vitro studies evaluating the accuracy of virtual occlusal records with intraoral scanners in completely dentate and partially edentulous arches.
RESULTS
Virtual occlusal records have shown promising results in terms of accuracy, with some studies reporting a high level of agreement with traditional methods. Key factors influencing the accuracy of VOR through intraoral scanners were identified which encompass multiple parameters such as scanner brands, imaging technology, scan quality, best-fit alignment, software algorithms, intermesh penetrations, and the number of sections and dimensions of the virtual occlusal record. In partially edentate areas, the lack of landmarks in the edentulous area compromises the accuracy of VOR, thus limiting the use of IOS in patients with missing teeth.
CONCLUSION
Understanding and recognizing these influencing factors will increase the predictability and reliability of dental treatments completed by using digital workflows. However, certain challenges need to be addressed which can influence its accuracy and limit its use in daily practice. Future research should focus on improving these factors to enhance the clinical applicability of virtual occlusal records.
Topics: Humans; Imaging, Three-Dimensional; Reproducibility of Results; Models, Dental; Software; Mouth, Edentulous; Computer-Aided Design; Dental Impression Technique
PubMed: 37882237
DOI: 10.1111/jopr.13787 -
The Journal of Prosthetic Dentistry Jan 2024The accuracy (trueness and precision) of intraoral scanners and complete arch scans remains controversial.
STATEMENT OF PROBLEM
The accuracy (trueness and precision) of intraoral scanners and complete arch scans remains controversial.
PURPOSE
The purpose of this in vitro study was to compare the trueness and precision of 3 intraoral scanners with various scan patterns.
MATERIAL AND METHODS
Four standard metal spheres were installed on a dental maxillary cast according to American National Standard/American Dental Association (ANSI/ADA) specification no. 132. Six distances among the center of spheres were measured with a coordinate measuring machine and used as references. Four different scanning patterns were assigned: zigzag, occlusal-palatal-buccal, occlusal-buccal-palatal, and molar-to-canine. Dental Wings and TRIOS 3 applied to the first 3 scan patterns, while True Definition applied to all patterns (n=30). Six distances in the scan files were also measured and calculated for relative errors of trueness and precision. A ratio less than 0.0025 was considered acceptable and used for binary outcome analysis. Differences among scanners and scan patterns in terms of trueness and precision were analyzed with the chi-squared test, Fisher exact test, and logistic regression (α=.05).
RESULTS
The zigzag scan pattern from TRIOS 3 and the occlusal-buccal-palatal pattern from True Definition exhibited 100% acceptable precision. TRIOS 3 revealed the highest number of acceptable trueness values in the occlusal-palatal-buccal scan (88.3%). The scan patterns from Dental Wings and TRIOS 3 were related to the trueness. TRIOS 3 and True Definition were 12.8 and 6.4 times more likely to obtain acceptable trueness than Dental Wings (P<.001). The zigzag scan pattern had the highest chance of obtaining acceptable trueness.
CONCLUSIONS
The scan patterns influenced the trueness and precision of the intraoral scanners in different ways. For the best trueness, TRIOS 3 should be applied with an occlusal-palatal-buccal scan pattern, Dental Wings should be applied with a zigzag scan pattern, while True Definition can be used with any scan pattern.
Topics: Imaging, Three-Dimensional; Computer-Aided Design; Dental Arch; Dental Impression Technique; Models, Dental
PubMed: 35256181
DOI: 10.1016/j.prosdent.2021.12.026 -
The Journal of Prosthetic Dentistry Aug 2023Digital scanning of different prosthodontic materials is commonplace in contemporary practice. However, the scannability of prosthodontic materials has not been...
STATEMENT OF PROBLEM
Digital scanning of different prosthodontic materials is commonplace in contemporary practice. However, the scannability of prosthodontic materials has not been thoroughly investigated.
PURPOSE
The purpose of this in vitro study was to evaluate the scanning accuracy and measure the unscanned area in a preset time limit of commonly used framework materials.
MATERIAL AND METHODS
A mandibular acrylic resin reference dental typodont with 3 teeth, with the central one prepared for a complete coverage crown, was digitized by using a desktop scanner. A complete coverage crown was generated in standard tessellation language (STL) format. Three groups were created from the digital design according to the crown material: milled polyetheretherketone (PEEK), milled airborne-particle abraded titanium, and milled polymethylmethacrylate (PMMA). They were scanned with the desktop scanner to be used as reference files for each group. The intraoral scanner Medit i700 was used to digitize each specimen 10 times (n=10). Using a nonmetrology grade software program, the deviations between the test STL file of the intraoral scanner and the reference STL file of the desktop scanner were assessed by using the RMS values. The unscanned surface area in a preset time limit of 6 seconds (scannability) was assessed. Groups were compared by using 1-way ANOVA followed by the Tukey post hoc test with Bonferroni correction when the results were significant. All tests were 2-tailed (α=0.05).
RESULTS
Regarding deviation analysis, RMS discrepancies were computed, and significant differences in trueness were found (P<.001) among the 3 studied groups. The titanium group had the highest trueness followed by the PEEK and PMMA groups, which were statistically similar (P>.05). Precision differed significantly among the 3 studied groups (P<.001). PEEK was the most precisely scanned material followed by titanium, and the PMMA group had the least precision. Regarding scannability, there were overall significant differences (P<.001). Titanium was the most scannable, followed by PEEK and then PMMA.
CONCLUSIONS
Airborne-particle abraded titanium had better trueness and scannability than PEEK and PMMA. However, PEEK was the most precisely scanned material.
Topics: Computer-Aided Design; Polymethyl Methacrylate; Prosthodontics; Titanium; Dental Impression Technique; Models, Dental; Imaging, Three-Dimensional
PubMed: 37468368
DOI: 10.1016/j.prosdent.2023.05.032 -
Journal of the Mechanical Behavior of... Aug 2023To summarize the existing scientific evidence on the effect of distinct intraoral (IOS) and extraoral (EOS) scanners in terms of their accuracy for image acquisition and... (Review)
Review
OBJECTIVE
To summarize the existing scientific evidence on the effect of distinct intraoral (IOS) and extraoral (EOS) scanners in terms of their accuracy for image acquisition and the marginal/internal adaptation of indirect restorations.
METHODS
The protocol of this scoping review is available online (https://osf.io/cwua7/). A structured search, with no date restriction, was performed in LILACS, MEDLINE via Pubmed, EMBASE, Web of Science, and Scopus, for articles written in English. The inclusion criteria were studies that considered at least two scanners, regardless of method (intra or extraoral), for the production of tooth-supported restorations. Two independent and blinded researchers screened the studies, collected and analyzed the data descriptively.
RESULTS
103 studies were included (55 on marginal/internal adaptation, 33 on accuracy, 5 on both outcomes, and 10 reviews). Most of them, shown clinically acceptable adaptation (<120 μm). Factors commonly related to the performance of scanners are: use of anti-reflection powders, method of image acquisition, and restoration/tooth characteristics. The need of anti-reflection powders was controversial. Different scanning principles seems to result on similar performance; IOS that combine them could be promising. The most explored systems were Omnicam - IOS, and inEos X5 - EOS, which showed similar performance on marginal/internal adaptation. Scarce studies explored the performance of EOS systems, especially in terms of accuracy. Different restoration designs as single-unit seemed not to modify the performance of scanners. Limited information is available regarding the planned cement space, restorative material and design (multi-unit restorations), as also techniques to measure adaptation.
CONCLUSIONS
Digital scanners are valid approaches to obtain accurate impressions resulting in clinically acceptable restorations. Systems that uses combined principles of image acquisition seems promising for optimal performance. Based on high discrepancy, the quality of evaluated evidence is low, and well-designed studies are still encouraged, especially considering validated IOS/EOS as a control comparison condition.
Topics: Powders; Computer-Aided Design; Tooth; Dental Prosthesis Design
PubMed: 37379673
DOI: 10.1016/j.jmbbm.2023.105975 -
Journal of Dentistry Nov 2023To review the factors that influence the accuracy of the maxillomandibular relationship at maximum intercuspation (MIP) acquired by using intraoral scanners (IOSs).
OBJECTIVE
To review the factors that influence the accuracy of the maxillomandibular relationship at maximum intercuspation (MIP) acquired by using intraoral scanners (IOSs).
MATERIAL AND METHODS
A systematic search was performed using five databases: MEDLINE/PubMed, Cochrane, Embase, World of Science, and Scopus. A manual search was also completed. Studies assessing the factors that influence the MIP acquired by using IOSs were included and organized based on the analyzed factor. Studies were evaluated by applying the Joanna Briggs Institute Critical Appraisal Checklist.
RESULTS
Twenty-nine articles were included. Seven factors have been identified: IOS system, scan extension, edentulous areas, number, location, and extension of occlusal records, occlusal force, tooth mobility, and alignment methods. Nine studies evaluated the influence of IOS system. Four studies assessed the influence of the extension of the arch scan. Three studies evaluated the effect of edentulous spaces. Four studies agreed on the impact of the number, location, and extension of the occlusal records on the MIP accuracy. One study assessed the influence of the occlusal force, showing a smaller average interocclusal space with increased occlusal force. One study evaluated the influence of tooth mobility. Seven studies analyzed the influence of the alignment method on the MIP accuracy.
CONCLUSIONS
Most of the studies reported no difference on the MIP accuracy between half- and complete-arch scans. Areas with 2 or more missing teeth reduce the MIP accuracy. A bilateral and frontal record including 2 teeth or a bilateral posterior occlusal including at least 4-teeth is indicated for maximizing the MIP accuracy.
CLINICAL IMPLICATIONS
When a complete-arch intraoral scans is obtained, a bilateral and frontal record including 2 teeth or a bilateral posterior occlusal record including at least 4-teeth is recommended for maximizing the accuracy of the MIP. When a half-arch intraoral scan is acquired, a posterior occlusal record including at least 4-teeth is indicated for optimizing the accuracy of the MIP.
Topics: Humans; Imaging, Three-Dimensional; Tooth Mobility; Dental Impression Technique; Models, Dental; Dental Arch; Mouth, Edentulous; Computer-Aided Design
PubMed: 37775027
DOI: 10.1016/j.jdent.2023.104718 -
Journal of Prosthodontics : Official... Dec 2023This study aimed to compare the marginal and internal fit of five-unit zirconia-based fixed dental prostheses (FDPs) fabricated using digital scans and conventional...
PURPOSE
This study aimed to compare the marginal and internal fit of five-unit zirconia-based fixed dental prostheses (FDPs) fabricated using digital scans and conventional impressions.
MATERIALS AND METHODS
Nine master models with three zirconia abutments were scanned with an intraoral scanner (test group), and nine conventional impressions (control group) of these same models were also made. The stone casts from these impressions were scanned with a laboratory extraoral scanner (D700, 3Shape, Copenhagen, Denmark). A total of 18 five-unit zirconia-based FDP frameworks (test group, n = 9; control group, n = 9) were manufactured. Marginal and internal fit (in μm) were evaluated using the replica method under micro-computed tomography. Analysis of variance (one-way ANOVA) and Kruskal-Wallis tests were used to compare continuous variables across two groups. A level of p < 0.05 was accepted as statistically significant.
RESULTS
The mean ± standard deviation of the marginal fit was 95.03 ± 12.74 μm in the test group and 106.02 ± 14.51 μm in the control group. The lowest marginal mean value was observed in the test group, with a statistically significant difference compared to the control group (F = 14.56, p < 0.05). The mean ± standard deviation of the internal fit was 103.61 ± 9.32 and 106.38 ± 7.64 μm, respectively, in the test and control groups, with no statistically significant difference (F = 1.56, p > 0.05). The mean values of both groups were clinically acceptable.
CONCLUSIONS
The five-unit zirconia-based FDPs fabricated with digital scans showed better fit than those in the conventional impression group. Within the limitations of this study, these results are encouraging, and continued progress in the digital field should allow for more accurate long-span restorations.
Topics: X-Ray Microtomography; Computer-Aided Design; Dental Impression Technique; Dental Marginal Adaptation; Zirconium; Dental Prosthesis; Dental Prosthesis Design
PubMed: 36627825
DOI: 10.1111/jopr.13639 -
Evidence-based Dentistry Sep 2023To analyze the clinical outcomes of implant-supported prostheses and tooth-supported fixed prostheses, fabricated from digital and conventional impression. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To analyze the clinical outcomes of implant-supported prostheses and tooth-supported fixed prostheses, fabricated from digital and conventional impression.
MATERIALS AND METHODS
The literature search was carried out on two electronic databases (PubMed and Cochrane Library). Randomized controlled trials (RCT) published from January 2011 to September 2022 were included. The bias risk was evaluated using Cochrane Risk of Bias Tool 2.0. Further screening was done for meta-analysis according to modified Newcastle-Ottawa scoring criteria. Forest plot was generated using a statistical method of inverse variance of random effect with 95% confidence interval.
RESULTS
A total of 8 randomized controlled trials were included for systematic review out of which four studies were based on tooth-supported fixed prosthesis and remaining four were based on implant-supported prosthesis. Further screening was conducted and three studies were eligible for meta-analysis. Tooth-supported fixed prosthesis fabricated from digital impression showed no significant difference in the marginal fit in any region measured, except for occlusal region where conventional impression showed more favorable marginal fit. Implant-supported prosthesis fabricated from digital impression showed survival rates ranging from 97.3 to 100% and there was no statistically significant difference in marginal bone loss (p = 0.14).
CONCLUSION
Implant-supported prostheses fabricated from digital and conventional impressions show no significant differences in their clinical outcomes. Tooth-supported fixed prostheses fabricated from digital impression have shown favorable findings in terms of marginal fit. Despite that, there is still lack of clinical trials with larger sample size and longer follow-up periods. Future studies that fulfill these two criteria are deemed necessary.
Topics: Humans; Dental Implants; Dental Prosthesis, Implant-Supported; Artificial Limbs; Prosthesis Implantation
PubMed: 37369705
DOI: 10.1038/s41432-023-00904-5