Faculty Bibliography

OBJECTIVES:/UNASSIGNED:This study evaluated the effect of argon plasma treatment (PLA) and its combination with sandblasting (SAN), silanization (SIL), and hydrophobic bonding resin (HBR) application on the micro-shear bond strength of water-aged restorative resin composite to a newly placed composite, simulating restoration repair. METHODS AND MATERIALS:/UNASSIGNED:Forty-five light-cured composite plates (20-mm long × 20-mm wide × 4-mm thick) were fabricated using a hybrid composite and stored at 37°C in distilled water for six months. The aged composite surfaces were treated according to the following experimental groups, varying both treatment and order of application: 1) SAN + SIL + HBR (control), 2) SAN + PLA for 30 seconds + SIL + HBR, 3) SAN + SIL + PLA + HBR, 4) PLA + SIL + HBR, 5) PLA + SIL, 6) PLA + HBR, 7) SIL + PLA + HBR, 8) SIL + PLA, and 9) PLA. After the surface treatments, four fresh resin composite cylinders (1.5-mm high × 1.5-mm diameter) of the same composite were built on each aged composite surface using a silicone mold. After water storage for 24 hours or one year, the specimens were submitted to shear bond strength testing. Data were statistically analyzed by two-way analysis of variance and Tukey's test (5%). RESULTS:/UNASSIGNED:Groups 1, 2, and 4 presented significantly higher bond strength means at 24 hours, although group 4 did not differ from group 7. Groups 5, 8, and 9 demonstrated significantly lower means than the other groups. Even though groups 1 and 2 had a significant bond strength reduction after 1 year, they still demonstrated higher bond strength at one year of storage. CONCLUSIONS:/UNASSIGNED:While PLA application combined with surface treatment methods demonstrated high bond strength results, this treatment alone was not as beneficial as other methods that included SAN, SIL and HBR.

STATEMENT OF PROBLEM/BACKGROUND:Color matching in restorative and prosthetic dentistry is important for the success of dental treatments, although communication with the dental laboratory remains subjective, and studies of the performance of objective communication methods are lacking. PURPOSE/OBJECTIVE:The purpose of this study was to evaluate color differences (ΔE) and compare color luminosity (L*) values among different types of digital photography equipment used to document tooth color, with and without a gray reference card, and to determine whether the gray card could be used to standardize color assessment in dental photography. MATERIAL AND METHODS/METHODS:Sixty photographs were made (n=10) using different equipment: a D7000 digital camera (Nikon Corp) with an 85-mm lens and wireless close-up flash (DC+WCF); close-up flash surrounded by 80 grams per square meter (gsm; specification of paper thickness) white printing paper (DC+WPP); ring flash (DC+RF); close-up flash attached to a dual-point rigid flash bracket (DC+DPRF); cross-polarizing filter attached to a close-up flash (DC+CPF); and iPhone 7 (I7). For all photographs, a gray reference card with known color values was positioned at the patients' mandibular teeth, acting as a parameter for the analysis of white-balanced digital photographs. Each photograph underwent white balance with the reference card and software. ΔE were obtained from each piece of equipment by comparing images with and without white balance (original photo) with software and the smallest ΔE achieved was used as the gold standard for comparisons of luminosity. Values of luminosity were subsequently obtained for the different equipment with and without white balancing the photographs; these values were compared using a general estimating equation with Huber-White standard error (α=.05). RESULTS:The use of a cross-polarizing filter was used as the gold standard for luminosity evaluation, as the smallest ΔE (3.4) among photographs were observed when those with and without white balance were compared. Luminosity results from the cross-polarizing filter method (DC+CPF) were not significantly different from those of the DC+DPRF (P=.73), DC+WPP (P=.106), and DC+WCF (P=.551) groups but were statistically different from DC+RF (P=.028) and I7 groups (P<.001). Use of a gray card was significant when a ring flash (P=.008) or the iPhone (P=.023) were used but not statistically significant for the other groups (P>.05). CONCLUSIONS:The use of a cross-polarizing filter results in more color-standardized photographs, while the ring flash system and the iPhone 7 result in less standardized photographs. The gray reference card had a significant effect when a ring flash system or iPhone 7 was used.

AIM/OBJECTIVE:The present work aims to compare a digital dental histoanatomical analysis method with chemical enamel dissolution for the study of dental morphology. MATERIAL AND METHODS/METHODS:Extracted maxillary anterior teeth were scanned under microcomputed tomography (μCT) (μCT 40; Scanco Medical), segmented, and reconstructed three-dimensionally (Amira, version 5.5.2; VSG). Following the digital acquisition of dental morphology, all specimens were acid treated with 5% formic acid for careful dissolution of the enamel layer. Six measurements (three buccopalatal and three mesiodistal) per specimen were performed, both digitally following the μCT scan and physically both before and after enamel dissolution. The obtained measurements were subjected to statistical analysis through concordance coefficient measurements and linear regression. RESULTS:A straight line correlation behavior with no statistically significant difference was found between both methods, with a concordance correlation coefficient of 97%. CONCLUSION/CONCLUSIONS:The digital, nondestructive, μCT-layered, three-dimensional reconstruction method presented comparable results to acid-etched enamel dissolution, confirming that both options are reliable for the histoanatomical analysis of enamel and dentin morphologies.

Cosmetic recontouring based on the enameloplasty of natural teeth is a treatment with esthetic benefits that can be considered both economical and safe. Not only does the clinician need to restore the harmony of the smile, but treatment planning must also take the functional aspects of the restoration into consideration. One way to recontour is through an additive technique with direct composite resin that improves the esthetic outcome of the final treatment. Of the various types of treatment that can be offered in the dental clinic, cosmetic recontouring is a conservative one with low biological and financial cost that obtains good functional and esthetic results. This article describes a clinical case including enameloplasty and the addition of direct composite resin to improve the balance and harmony of the smile and dentition.

Proper gingival displacement is an important prerequisite to obtain good quality impressions. Retraction pastes could eliminate the need for retraction cords, as they have advantages such as comfort reported by patients, faster technique, ease of use, no need for anesthesia, and reduced tissue trauma. The objective of this paper was to present a clinical case of ceramic veneers and crowns in which a retraction paste was used for gingival displacement during both the impression and cementation stages, with 3 years of follow-up. Treatment planning consisted of the replacement of preexisting crowns and ceramic veneers on the anterior teeth. After finishing the preparations, gingival displacement with Astringent Retraction Paste was performed without anesthesia or the use of cords and the impression was taken. Before cementation of the crowns and veneers, the Astringent Retraction Paste was applied. Avoiding the use of cords during cementation prevented trauma. The soft tissue margins remained stable and healthy after a period of 3 years. It can be concluded that retraction pastes could be indicated for displacement of soft tissue when preparation margins are at the gingival level or slightly intrasulcular prior to impressions, restoration cementations, direct restorations, and before relining provisional restorations. Clinical significance: The impression appointment can be traumatic to some patients. The use of cords for gingival displacement usually requires local anesthesia and is time consuming. Retraction astringent pastes instead of cords seems to be a good option for some cases in gingival tissue displacement.

The stability and health of the periodontal tissues should be a common goal for all dental care providers with regard to natural or restored teeth as well as implant-supported restorations or any other type of prosthesis. The objective of this study was to address the key aspects to be respected when executing adhesive oral rehabilitations involving ceramic restorations, regardless of their thickness, and to reinforce the importance of each step to ensure the success and longevity of the treatment from a periodontal standpoint. This article reviews the fundamentals of the periodontics that relate directly or indirectly to adhesive ceramic dental restorations, and also addresses their clinical relevance.

OBJECTIVE:To test the effects of different adhesive protocols and silane application on the adhesive durability to a Lithium Disilicate reinforced glass ceramic. METHODS:Forty disks of 13 mm diameter (E.max Press) were used. After etching with 9.5% HF for 20 seconds, disks were randomly assigned into 4 groups according to the adhesive/silane protocol: silane application only (SIL); silane application followed by adhesive (SILXP-XP Bond); silane-containing adhesive (SBU-ScotchBond Universal); silane application followed by silane-containing adhesive (SILSBU). Four resin composite cylinders of 1-mm diameter and 3-mm height were made on each ceramic disk and tested in shear. Specimens were stored in water for 24 hours or 12 months prior to testing. Results were statistically analyzed by two-way ANOVA and Tukey test. RESULTS:After 24 hours, the highest SBS values were observed for SILXP and SILSBU. However, after 12 months, SILXP and SILSBU presented a significant reduction in SBS, while the highest SBS were observed for SIL. For SBU, no significant reduction in SBS was observed, however, it showed the lowest SBS after 12 months. CONCLUSIONS:Regardless of the presence of silane in the composition of SBU, previous silane application is still recommended prior to cementation of Lithium Disilicate. CLINICAL SIGNIFICANCE/CONCLUSIONS:The application of silane as a separate step is recommended prior to cementation of Lithium Disilicate reinforced glass-ceramic, independent of the presence of silane within the universal adhesive solution.

OBJECTIVE:To describe a novel technique that helps the clinician on promoting a midline diastema closure with appropriate width proportions based on previous wax up, avoiding excesses of the resin material on the gingival area, which could lead to possible inflammation. MATERIALS AND METHODS/METHODS:Two different silicone indexes were made over a wax up to perform a diastema closure. RESULTS:The use of a silicone index made with putty polyvinyl siloxane (PVS) material and another index made with putty and light PVS materials performed over a modified wax up, helped on achieving esthetically pleasant diastema closure with appropriate proportional widths, respecting the gingival tissue. CONCLUSIONS:The use of a novel silicone index technique allowed for ensuring the same width for both upper central incisors in a midline diastema closure, improving gingival tissue's health. CLINICAL SIGNIFICANCE/CONCLUSIONS:The main difficulties regarding diastema closure are related to reaching an appropriate width proportion of the central incisors and avoiding a ledge at the gingival aspect of the contact area, which could become a plaque and food trap. This article describes, step-by-step, how to avoid such diastema closure issues, ensuring the width proportions of the upper central incisors.

The understanding of cuspal deflection and volumetric shrinkage of resin composites is necessary to assess and improve the placement techniques of resin-based materials. The aim of this study was to investigate the cuspal deflection and its relationship with volumetric polymerization shrinkage of different bulk-fill resin composites. The investigation was conducted using non-contact phase microscopy and micro-computed tomography. Thirty custom-milled aluminum blocks were fabricated for microscopy analysis and thirty-six tooth models with standardized Class I cavities were used for micro-computed tomography analysis. Results showed that high-viscosity composites present higher cuspal deflection compared to bulk-fill composites. The filler loading of resin composites seems to have an effect on cusp deflection, since the higher the filler content percentage, the higher the cusp deflection. On the other hand, it seems to have an opposite effect on volumetric shrinkage, since higher filler loadings produced lower volumetric shrinkage percentages.