Faculty Bibliography

OBJECTIVE:To describe the use of the injectable resin composite restorative technique with a flowable resin material, in a clinical case with esthetic problems associated with irregular tooth anatomies, allied with a finishing, and polishing protocol due to staining after 1 year of use. CLINICAL CONSIDERATIONS/UNASSIGNED:The presented case report helped to achieve an immediate highly esthetic restoration with appropriate width proportions based on a previous wax-up. After 1 year of use, restorations presented staining; therefore, finishing and polishing procedures were required to re-achieve acceptable esthetic results and thus increase restoration's survival. CONCLUSIONS:The use of the presented technique allowed to obtain a simple and predictable workflow; however, care must be taken on the follow up of the restorations due to intrinsic characteristics of the flowable resin material. CLINICAL SIGNIFICANCE/CONCLUSIONS:The use of the presented injectable technique helped on obtaining a precise anatomy replicating a diagnostic wax-up, thus improving marginal precision and achieving a highly esthetic and functional immediate outcome, with an easy workflow when appropriately planned and executed. However, it also presented low color stability after 1 year of use only, thus, requiring attention from clinicians in regard to its maintenance over time.

OBJECTIVE:To evaluate, through microcomputed tomography (μCT), the cement film thickness of veneers and crowns made with different provisional materials. MATERIAL AND METHODS/METHODS:A veneer and a crown preparation were performed on a central incisor and a second molar of a dental model, respectively, scanned with an intraoral scanner, and the .stl files were exported to an LCD-based SLA three-dimensional (3D)-Printer. Twenty-four preparations were 3D-printed for each veneer and crown and divided into four groups (n = 6/group): (a) Acrylic resin (Acrílico Marche); (b) Bisacrylic resin (Protemp 4); (c) PMMA computer-aided design and computer-aided manufacturing (CAD-CAM) (Vipiblock); and (d) 3D-printed resin for provisional restorations (Raydent C&B for temporary crown and bridge). Veneers and crowns restorations were performed and cemented with a flowable composite. Each specimen was scanned with a μCT apparatus, files were imported for data analysis, and cement film thickness was quantitatively measured. Data were analyzed by 2-way ANOVA and Tukey post-hoc tests (α = .05). RESULTS:Crowns presented a thicker cementation film than veneers (P < .05).The bisacrylic resin showed the smallest veneer film thickness, similar to the acrylic resin (P = .151), which was not significantly different than the PMMA CAD/CAM material (P = .153). The 3D printed provisional material showed the thicker film, different than all other materials (P < .05). The bisacrylic resin showed a cement film thickness with a high number of voids in its surface. For crowns cementation, the 3D printed provisional material showed the thicker cementation film, different than all other materials (P < .05). CONCLUSIONS:Different provisional materials present different film thicknesses. The 3D printed provisional material showed the highest veneer and crown film thicknesses. Veneers film thicknesses were smaller than crowns for all provisional materials. CLINICAL SIGNIFICANCE/CONCLUSIONS:The 3D printed provisional material studied can be satisfactorily used, presenting appropriate adaptation with the tooth preparation, however, it shows the highest cement film thickness for both veneers and crowns cementations when compared with other provisional materials. A better internal fit, or smaller cement film thickness is obtained by CAD/CAM materials, acrylic and bisacrylic resins. Veneer cementation showed a smaller cement film thickness compared with crown cementation for all provisional materials.

CLINICAL RELEVANCE/UNASSIGNED:Shortened light curing does not affect volumetric polymerization shrinkage or cohesive tensile strength but negatively affects the shear bond strength of some bulk-fill resin composites. When performing shortened light curing, clinicians should be aware of the light output of their light-curing units. SUMMARY/CONCLUSIONS:Purpose: To evaluate volumetric polymerization shrinkage (VPS), shear bond strength (SBS) to dentin, and cohesive tensile strength (CTS) of bulk-fill resin composites (BFRCs) light activated by different modes.Methods and Materials: Six groups were evaluated: Tetric EvoCeram bulk fill + high mode (10 seconds; TEC H10), Tetric EvoFlow bulk fill + high mode (TEF H10), experimental bulk fill + high mode (TEE H10), Tetric EvoCeram bulk fill + turbo mode (five seconds; TEC T5), Tetric EvoFlow bulk fill + turbo mode (TEF T5), and experimental bulk fill + turbo mode (TEE T5). Bluephase Style 20i and Adhese Universal Vivapen were used for all groups. All BFRC samples were built up on human molar bur-prepared occlusal cavities. VPS% and location were evaluated through micro-computed tomography. SBS and CTS tests were performed 24 hours after storage or after 5000 thermal cycles; fracture mode was analyzed for SBS.Results: Both TEC H10 and TEE H10 presented lower VPS% than TEF H10. However, no significant differences were observed with the turbo-curing mode. No differences were observed for the same BFRC within curing modes. Occlusal shrinkage was mostly observed. Regarding SBS, thermal cycling (TC) affected all groups. Without TC, all groups showed higher SBS values for high mode than turbo mode, while with TC, only TEC showed decreased SBS from high mode to turbo modes; modes of fracture were predominantly adhesive. For CTS, TC affected all groups except TEE H10. In general, no differences were observed between groups when comparing the curing modes.Conclusions: Increased light output with a shortened curing time did not jeopardize the VPS and SBS properties of the BFRCs, although a decreased SBS was observed in some groups. TEE generally showed similar or improved values for the tested properties in a shortened light-curing time. The VPS was mostly affected by the materials tested, whereas the SBS was affected by the materials, curing modes, and TC. The CTS was not affected by the curing modes.

OBJECTIVES/OBJECTIVE:To perform a review on the influence of preheating and/or heating of resinous and ionomeric materials on their physical and mechanical properties and to discuss the benefits and methods of preheating/heating that have been used. MATERIAL AND METHODS/METHODS:A search was performed in the Pubmed, Scopus, Scielo, and gray literature databases. In vitro studies published from 1980 until now were searched using the descriptors "composite resins OR glass ionomer cements OR resin cements OR adhesives AND heating OR preheating." Data extraction and quality of work evaluation were performed by two independent evaluators. RESULTS:At the end of reading the search titles and abstracts, 74 articles were selected. Preheating of composite resins reduces viscosity, facilitates adaptation to cavity preparation walls, increases the degree of conversion, and decreases the polymerization shrinkage. Preheating of resin cements improves strength, adhesion, and degree of conversion. Dental adhesives showed good results such as higher bond strength to dentin. However, unlike resinous materials, ionomeric materials have an increase in viscosity upon heating. CONCLUSIONS:Preheating improves the mechanical and physical properties. However, there is a lack of clinical studies to confirm the advantages of preheating technique. CLINICAL RELEVANCE/CONCLUSIONS:Preheating of dental restorative materials is a simple, safe, and successful technique. In order to achieve good results, agility and training are necessary so the material would not lose heat until the restorative procedure. Also, care is necessary to avoid bubbles and formation of gaps, which compromises the best restoration performance.

AIM/OBJECTIVE:Die silicone materials are used to build chairside composite restorations. The purpose of this study was to compare the flowability, dimension accuracy, and tear strength of four elastomeric die materials. MATERIAL AND METHODS/METHODS:Materials were divided into four groups: Mach-2 (M2), Scan Die (SD), GrandioSO Inlay System (GIS), and Impregum-F (IM). Flowability analysis was carried out using the shark fin test (SFT). For dimension accuracy, impressions were taken from a premolar Class I preparation and an elastomeric model was cast. Composite resin restorations were built and positioned into the premolar for gap measurement. The mean gap length was divided into three levels: acceptable (A), not acceptable (NA), and misfit (M). For tear strength, strip specimens were made with a V-shaped notch (n = 6). The specimens were tested in a universal machine until tear. All data were analyzed statistically with a confidence interval of 95%. RESULTS:GIS showed the lowest flowability values, with no differences between IM, M2, and SD. For dimension accuracy, IM showed 100% 'A' gap values, followed by M2 (80%), SD (60%), and GIS (60%). For tear strength, IM showed the highest values, followed by M2, GIS, and SD. CONCLUSIONS:M2, SD, and IM had similar flowability, while GIS had the lowest. IM presented higher tear strength than M2, followed by GIS and SD. IM showed the highest degrees of acceptable gap filling, followed by M2.

Background/UNASSIGNED:Some composite resins contain luminophorous agents in order to reproduce tooth fluorescence. The objective of this study was to compare the fluorescence spectra emitted by composite resins with those of human enamel and dentin, and their emission behaviour after a 90-day natural aging period. Material and Methods/UNASSIGNED:<0.05). Results/UNASSIGNED:Fluorescence spectra baseline values of composites demonstrated no differences in intensity among the excitation peaks tested, with maximum emission found at the peak of 450 nm. Enamel and dentin spectra varied with different excitations, and the greater the excitation, the longer the wavelength in comparison to composite resins. After 90 days, XT presented an increase in fluorescence intensity, while OP and ED showed a reduction when compared with baseline values. Conclusions/UNASSIGNED:Composite resins, dental materials, fluorescence, fluorescence spectrometry.

OBJECTIVES/OBJECTIVE:to evaluate the probability of survival and failure modes of lithium-disilicate, feldspathic-ceramic, and resin-nanoceramic anterior veneers cemented on dentin analog substrates after sliding-contact step-stress accelerated life testing (SSALT). METHODS:A virtual incisor tooth preparation was produced with a reduction of 1.5mm at the incisal edge and of 0.7mm buccally. A .STL file of the preparation was generated and CAD/CAM based G10 dentin-analog material was used for testing. Laminate veneers were milled in three different materials: lithium-disilicate (LDS, E.max CAD), resin-nanoceramic (RN, Lava Ultimate), and feldspathic-ceramic (FELDS, Vita Blocks). SSALT was employed where a spherical indenter contacted the veneer, slided along its interface with G10 to lift off and start a new cycle at 2Hz in water. Qualitative fractography was performed. The probability of survival (90% confidence-bounds) was calculated for several load/cycle missions. RESULTS:The probability of survival for a mission of 50,000 cycles decreased from 50 up to 150N equally for all groups and were not different between them. At 200N, the probability of survival was significantly lower for FELDS (10%) compared to RN veneers (41%), whereas LDS presented intermediate values (22%). The characteristic strength of RN (247N) was significantly higher than LDS (149N), and FELDS (151N). In FELDS and LDS, hackles, wake hackles and twist hackles indicated the direction of crack propagation. In RN, hackles were observed. CONCLUSIONS:Differences in probability of survival were observed only at 180 and 200N between groups. Failure modes were similar with veneer fracture down to the tooth-analog substrate.

OBJECTIVE:To evaluate the influence of the degree of dentin moisture on interfacial ultramorphology and bond strength (μTBS) of universal adhesives. MATERIALS AND METHODS/METHODS:Futurabond U (FBU), Scotchbond Universal (SBU), Adhese Universal (ADU), and Prime&Bond active (PBA) were used. After acid-etching, moist or over-dried dentin surfaces were tested. Teeth were restored for scanning and transmission electron microscopy (n = 3) and μTBS evaluation (n = 5). μTBS results were analyzed by two-way ANOVA and Tukey. RESULTS:For moist dentin, a well-formed hybrid layer (HL) was observed. However, when applied to over-dried dentin, remarkable differences were observed. Defects, gaps, and reduced HL thickness were observed mainly for ADU and FBU. When applied to wet dentin, μTBS values were similar for all adhesives, except for FBU, which was significantly lower. When applied to over-dried dentin, PBA presented the highest μTBS values, followed by SBU, ADU, and FBU. ADU presented significantly lower μTBS when applied to over-dried dentin. CONCLUSION/CONCLUSIONS:PBA, SBU, and FBU μTBS values were not sensitive to the degree of moisture. Even though application to over-dried dentin revealed defects, gaps and reduced HL thickness for SBU, ADU, and FBU, μTBS analysis only revealed a significant reduction for ADU. CLINICAL SIGNIFICANCE/CONCLUSIONS:Universal adhesives can be applied in either self-etching or etch-and-rinse mode. However, clinicians are not aware which universal adhesives should be strictly applied on a moist dentin for bonding in the etch-and-rinse mode.

This technique article describes the duplication of a definitive implant-supported computer-aided design and computer-aided manufacture (CAD-CAM) crown with soft-tissue modification on a misplaced implant. Gingival contours were ideally shaped in the stone die, and a custom healing abutment was designed. After scanning the modified surface, images were correlated with the initial intraoral digital scan, and the definitive restoration was designed, milled, and delivered with an ideal soft-tissue emergence profile.