Five-year Randomized Clinical Trial on the Performance of Two Etch-and-rinse Adhesives in Noncarious Cervical Lesions

SUMMARY Objectives: To evaluate the 5-year clinical performance of two-step etch-and-rinse adhesives in noncarious cervical lesions (NCCL). Methods and Materials: The sample comprised 35 adults with at least two similar-sized NCCL. Seventy restorations were placed, according to one of the following groups: Adper Single Bond 2 (SB) and Ambar (AM). The restorations were placed incrementally using a resin composite (Opallis). The restorations were evaluated at baseline and after 6 and 18 months and 5 years using some items of the FDI criteria. The differences in the ratings of the two materials after 6 months, 18 months, and 5 years were performed with Friedman repeated measures ANOVA by rank and McNemar test for significance in each pair (α=0.05). Results: Five patients did not attend the 60-month recall. No significant differences were observed between the materials for any criteria evaluated. Twenty-one restorations failed (12 for SB and 9 for AM) after 60 months. Thus, the retention rate for SB at 60 months were 55.6% for SB and 71% for AM (p=0.32). After 60 months, 12 restorations (6 for SB and 6 AM) showed some loss of marginal adaptation (p=1.0). Slight marginal discoloration was observed in 10 restorations (6 for SB and 4 AM; p=0.91). Five restorations (2 for SB and 3 for AM) showed recurrences of caries (p=1.0). Conclusions: Both two-step etch-and-rinse adhesives—Adper Single Bond 2, a polyalkenoic acid-containing adhesive, and Ambar, a 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-containing adhesive—showed acceptable clinical performance after 60 months.

Evaluation of the Validity of Digital Optical Microscopy in the Assessment of Marginal Adaptation of Dental Adhesive Interfaces

Analysis of marginal adaptation of dental adhesive interfaces using scanning electron microscopy has proven to be a powerful nondestructive method to evaluate the quality of adhesion. This methodology is, however, time-consuming and needs expensive equipment. The purpose of this study was to evaluate the possibility and efficiency of using a digital optical microscope (DOM) to perform marginal analysis and to compare it with the scanning electron microscope (SEM) analysis. Fifteen defect-free molars were selected for this study. Class V cavities were prepared and restored with resin composite, and epoxy replicas were obtained from silicone impressions of the restored teeth. Custom-made image analysis software was then used to measure the percentage of the noncontinuous margins (NCM) of each sample. To compare the DOM to the gold standard, SEM, each sample was analyzed 10 times using the DOM and three times using the SEM, by the same experienced operator. The repeatability coefficient and concordance were evaluated, and a Bland and Altman analysis was used for comparison of the two methods of measurements. To validate the DOM analysis method, an ANOVA approach (Gage R R) was used. Repeatability and reproducibility, which are two components of precision to validate the DOM analysis system, were calculated. For this, the same restorations were analyzed by two additional operators three times with the DOM. The duration of each step of the analysis using both methods was also recorded as a secondary outcome. Regarding the repeatability of each method, the Friedman test showed no statistically significant difference within the repetitions of measurements by SEM and DOM (p = 0.523 and p = 0.123, respectively). Moreover, the Bland-Altman analysis revealed a bias of 0.86 and concluded no statistically significant difference between the two methods, DOM and SEM. ANOVA evaluated DOM measurement system variation including the variances of repeatability and reproducibility that represented, respectively, 0.3% and 4% of the variance components. Reproducibility or inter-operator variability represented the principal source of variability with a statistically significant difference (p = 0.024). The time required for analysis with SEM was almost double that of DOM. The use of digital optical microscopy appears to be a valid alternative to the SEM for the analysis of marginal adaptation of dental adhesive interfaces. Further studies to evaluate the effect of training of operators in digital optical microscopy could reveal higher accuracy for this method and inter-operator agreement when experience is gained.

Lost-wax or laser sintering? Findings on marginal and internal adaptation of metallic copings

Marginal and internal adaptation are parameters of crucial importance to the success of prosthetic crowns. Automatized process creates an expectative of superior or equivalent results compared to restorations manufactured ​​by conventional lost-wax technique. The purpose of this study was to evaluate the marginal adaptation and internal adaptation (cement space) of metal-ceramic crown copings produced by lost-wax (LW) and direct metal laser sintering (DMLS) techniques. An artificial lower first molar was prepared for a full crown, duplicated in plaster and scanned. Twenty metal-ceramic crown copings were fabricated in cobalt-chromium by the two techniques (n=10). The copings were filled with low viscosity silicone and seated on the prepared tooth, resulting in a replica of the internal space. The pellicle formed was embedded in heavy body silicone, sectioned and captured by means of a stereomicroscope at 50x magnification, according to replica technique (RT). Shapiro-Wilk test followed by Holm-Sidak test were used for statistical analysis (α=.05). Marginal adaptation presented no difference between LW (101.5 ± 41.6) and DMLS (86.3 ± 39.9) groups (p=0.24). Conventional LW technique showed significantly lower occlusal (p<0.008) and axial spaces (p<0.03). Measurements of all regions showed numerically larger adaptation values than that defined during design​​ for DMLS group. Both the LW technique and the DMLS technique are within the clinically acceptable.

Review of Marginal Adaptation and Fracture Resistance of Computer Aided Design/Computer Aided Manufacturer (CAD‐CAM) Fabricated Endo-crowns

Background: Zirconia-based restorations have become more popular in dentistry during the last two decades. Patients choose metal-free restorations, preferring materials with similar attributes to natural teeth and similar light scattering characteristics, resulting in a nice esthetic appearance. Restoring a root canal treated teeth is one of the hot topics today. endo crown materials can be either; feldspathic, glass-ceramic, monolithic hybrid ceramic or composite material. Considering the marginal gap of endocrown, an important cause of failure of treatment, the current study evaluated the marginal gap of CAD‐CAM concocted endo-crowns. Materials and Methods: This research is an analysis systemic review study was conducted between January 2020 and October 2021. We followed the PRISMA principles and recorded this systematic review using the PROSPERO database to find and identify published literature related to the marginal adaptation of CAD-CAM-fabricated endocrown. The search will include all relevant articles through the end of 2021. Finally, 24 papers on marginal clearance and fracture resistance in coronary arteries were reviewed. Results: The electronic database search yielded 98 studies that were relevant. After cross-referencing, further seven studies were added. After a full-text analysis and duplicate reduction, 74 of the 98 articles were eliminated. 5 clinical (prospective) studies, 19 in vitro studies were found. Conclusion: This analysis of the recent literature on the marginal seating integrity and fracture resistance of CAD/CAM made-up endo-crowns showed that the endo-crown had superior marginal seating integrity than classical full crown. CAM/CAM showed statistically significant higher mean fracture resistance than MAD/MAM.

Comparison of Marginal and Internal Adaptation in Endocrowns Milled from Translucent Zirconia and Zirconium Lithium Silicate

Purpose. This study aimed to compare marginal and internal adaptation in endocrowns made from translucent zirconia and zirconium lithium silicate using CAD-CAM technology. Materials and Methods. Twenty-eight freshly extracted upper molars were mounted in acrylic resin and underwent root canal therapy and endocrown preparation up to 2 mm above the cementoenamel junction. Endocrowns were CAD-CAM milled from zirconium lithium silicate (ZLS) and translucent zirconia (Zr). Internal and marginal adaptation was assessed by the replica technique before cementation. Marginal adaptation was evaluated by a stereomicroscope (×32) before and after cementation and also after thermomechanical aging. Results. The ZLS group showed significantly higher internal adaptation compared to the Zr group ( P = 0.028), while the marginal adaptation differences, at different times with different methods, were not statistically significant ( P > 0.05). Axiomarginal angle had the highest and axiopulpal angle showed the lowest adaptation in both groups. The cementation process and thermomechanical aging increased the marginal gap in both groups significantly ( P < 0.001). The marginal gap assessed by the replica technique before cementation was 7.11 µm higher than direct view under a stereomicroscope with intraclass correlation coefficient of 0.797. Conclusion. Zirconia seems to be an acceptable material for endocrown with comparable internal and marginal adaptation to ZLS. Cementation and thermomechanical aging had significantly negative effects on marginal gap. The marginal gap assessed by the replica technique was higher than direct view under the stereomicroscope technique.

Comparative Evaluation of Marginal Fit of Three Provisional Restorative Materials in Different Mediums: An In-Vitro Study

Temporaries are used as placeholders before the permanent crowns are installed. If the temporary crown is not fitted properly the tooth can be subject to increased decay and gums can become inflamed causing gingivitis which leads to other more serious problems. A provisional fixed restoration will provide a template for defining tooth contour, esthetics, proximal contacts, ridge contacts and occlusion. Margins made by the indirect technique are considered to be more accurate than those made by the direct technique. The purpose of this in vitro study was to compare the marginal accuracy of provisional crowns made from three different biomaterials using the established indirect method in different environments and to evaluate the effect of water absorption on polymerization shrinkage and the effect of polymerization shrinkage occurring in dry storage for a week. Method:Variables used in this study are: a) Revotek LC-light cured composite b) Protemp II c) poly methyl methacrylate. An aluminium master die was machined with dimensions: 5mm length, 10mm gingival diameter, 5 degree taper, and 1mm shoulder then dental stone die was prepared by making an impression of this experimental model using a poly vinyl siloxane material. Both group A and group B consisted of seven specimens each of DPI, ProtempII, Revotek LC. The specimens were evaluated using measuring microscope (Biolux), which had an eyepiece graticule of 1/10th of an mm. The seven specimens in group A (DPI, ProtempII, Revotek LC) were kept in air at room temperature for one week on the dental stone cast and the readings were tabulated and the mean values were obtained. The seven specimens in group B (DPI, ProtempII, and Revotek LC) were kept in water at room temperature for one week and the readings were tabulated in the same manner and the mean values were obtained. Results: Comparative statistics of the mean values of the specimens kept in air at room temperature showed that DPI had the least marginal discrepancies followed by ProtempII, Revotek LC. The values were highly significant (.002) Comparative statistics of the mean values of the specimens kept in water at room temperature showed that DPI had the least marginal discrepancies followed by Revotek LC, ProtempII. The values were highly significant (.009). Conclusion: After one week in air at room temperature and after one week in water at room temperature DPI recorded the minimal marginal discrepancy. When stored in air at room temperature, DPI had the best marginal adaptation. All of the materials showed evidence of continued polymerization shrinkage after storage in air for a week. Water absorption compensated for polymerization shrinkage in DPI and ProtempII whereas Revotek LC was an exception. Keywords: light cured composite, Protemp II-Bis –acryl composite, poly methyl methacrylate, marginal adaptation, provisional restoration.

The outcome of direct composite restorations using the dental operating microscope

Background. The objective of the present study was to compare the outcome of direct composite restorations, with and without the use of additional magnification. Methods. Twenty extracted molars were selected for the study. Class 1 Black cavities were prepared. All teeth were etched, and bonding agent was applied. Teeth were assigned randomly into two groups of ten each. Group I: restorations were done without the use of magnification, first by placing a layer of SDR® flow +Bulk Fill Flowable on the base of the cavity, and then restoring the morphology with Ceram.X SphereTEC® One. Group II: the same protocol was applied, but using the dental microscope. Teeth were then evaluated before and after the finishing protocol by 5 dental professionals using a series of established criteria. The results were documented and statistically analyzed using the non-parametric Mann-Whitney test. Results. Statistically significant differences were found when using magnification, before the polishing protocol in “marginal adaptation integrity” and “excess material”, and after polishing in “marginal adaptation integrity”. Conclusions. Magnification may be used to increase the quality of the final direct posterior restoration by improving the marginal adaptation integrity, reducing excess material, preventing marginal microleakage, and avoiding subsequent failure.

Accuracy in marginal and/or internal adaptation of full-coverage fixed prostheses made with digital versus conventional impressions: an overview of systematic reviews and meta-analysis

Review question / Objective: Is the accuracy (marginal adaptation and / or internal adaptation) of fixed full coverage prostheses made with digital impressions better than conventional impressions? Eligibility criteria: Inclusion criteria• Systematic reviews and / or meta-analyzes that evaluated the precision (marginal adaptation and / or internal adaptation) of full coverage fixed prostheses on natural teeth in clinical studies and on tooth replicas in in vitro studies.• Systematic reviews and / or meta-analyzes comparing digital impressions with an intraoral scanner versus conventional impressions taken with any impression material.• Systematic reviews and / or meta-analyzes of randomized clinical trials (RCTs), prospective comparative and in vitro and non-randomized clinical trials.Exclusion criteria:• Systematic literature reviews, case reports, pilot studies• Studies evaluating the seating of crowns on implants and partial restorations• Studies with no response from the author to the requested information query.