Purpose: To evaluate the roughness and color change of a conventional acrylic resin and a bis-acryl resin, submitted to different types of polishing and exposed to a staining solution. Materials and Methods: One hundred specimens were manufactured from an autopolymerizing conventional acrylic resin (Duralay, shade 66) (n = 50) and a bis-acryl resin (Protemp 4, shade A3) (n = 50) according to the manufacturers' instructions. Specimens were subdivided into 10 groups (n = 10), according to the type of resin and polishing method, including no-polishing (control groups for acrylic resin [tungsten bur finishing] and bis-acryl resin [cotton and alcohol]), Enhance System, Edenta kit, Labordental kit, and sandpaper. The specimens were immersed in a staining solution (coffee at 60°C) for 7 days. Surface roughness was evaluated before the first immersion (baseline -Ra1) and after 7 days (Ra2). The color change (E) was determined after 24 hours (E1) and 7 days (E2), by CIE L * a * b * scale. Data were statistically analyzed with 3-way ANOVA for repeated measures test and Tukey test (α = 0.05). Results: According to 3-way ANOVA test, material, polishing techniques, and polishing*material factors exhibited statistically significant influence (p < 0.0001) on the roughness, and, for color change, material, polishing techniques, time, polishing*material, and material*time factors were statistically significant (p < 0.0001). The polishing techniques successfully reduced the surface roughness of acrylic resin groups, when compared to control (p < 0.001), but for bis-acryl resin, results were not different from the control group (Enhance: p = 0.954, Edenta: p = 0.866, sandpaper: p = 0.366, Labordental: p = 0.945). Surface roughness was not affected by the immersion in staining solution for 7 days. Color change of acrylic resin groups after 24 hours and 7 days of immersion exhibited a clinically acceptable value ( E < 3.7) with the exception of the Enhance group, and all bis-acryl resin groups exhibited a clinically unacceptable color change value ( E > 3.7) independent of polishing technique and time interval (E1 and E2). Conclusions: Roughness of both materials was similar when the polishing techniques studied were performed, although Ra values were superior to the clinically acceptable values (0.20 µm), and were not affected by the immersion protocol studied; however, when esthetics are critical, the selection of material type is more important than the surface treatment technique used, and bis-acryl resin was more susceptible to clinically unacceptable color change after immersion in a staining solution.Provisional restorations should be prepared to reproduce and maintain the tooth's natural properties, such as size, position, shape, color, surface texture, and dental translucency. 1-3 Currently, with the development of new dental materials, professionals have many options to manufacture provisional restorations. These options include poly methyl methacrylate (PMMA), poly ethyl methacrylate (PEMA), polyvinyl ethyl methacrylate (P...

Testes de dureza; Esmalte dentário; Bebidas isotônicas. Hardness tests; Dental enamel; Foods for persons engaged in physical acti viti es. Objecti ve: To evaluate the microhardness of dental enamel aft er exposure to isotonic beverages. Method: Twenty-fi ve specimens were prepared and allocated to fi ve groups: G1: control (disti lled water), G2: Gatorade® tangerine at room temperature, G3: Gatorade® tangerine at 9 0 C, G4: Gatorade® lemon at room temperature, and G5: Gatorade® lemon at 9 0 C. Vickers microhardness was measured before (T1) and aft er (T2) immersion of the specimens in these soluti ons, by the applicati on of a load of 100 g during 15 seconds. The acid challenge had the durati on of 1 minute followed by 3 minutes in arti fi cial saliva. This cycle was repeated 5 ti mes, totalizing 20 minutes, and was performed twice a day, during 3 consecuti ve days with a 12-hour interval between them. At the end of the sixth acid challenge, new microhardness measurements (100 g/15 seconds) were made. Data were presented by descripti ve stati sti cs (maximum, minimum, mean and standard deviati on) using ANOVA and paired t-test. A signifi cance level of 0.05 and 95% confi dence interval were used. Database and stati sti cal analyses were done using the SPSS 13.0 soft ware. Results: The analysis of Vickers microhardness in T1 and T2 showed stati sti cally signifi cant diff erence before and aft er immersion of the specimens in the isotonic beverages (t =10.49; p =0.000). All experimental groups presented a decrease of the microhardness values aft er the acid challenge (T2). There was stati sti cally signifi cant diff erence between G3 and G5 in T2 (p<0.05). Conclusion: The beverages evaluated in this study caused permanent dental enamel demineralizati on with signifi cant diff erence between the initi al and the fi nal microhardness values in the groups subjected to the acid challenge.

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To evaluate the eff ect of diff erent sizes of load parti cles and diff erent storage ti mes on the surface microhardness of three estheti c restorati ve composites. Method: Sixty disc-shaped specimens (5 mm diameter and 2 mm high) were fabricated and divided into 6 groups (n=10) according to the evaluated resin: Filtek Z350 (3M/ESPE), with medium-sized parti cles classifi ed as nanoparti culate; Filtek Z250 (3M/ESPE), with medium-sized parti cles classifi ed as micro-hybrid; and Durafi ll (Heraeus-Kulzer), with medium-sized parti cles classifi ed as microparti culate. The specimens were stored in disti lled water for 24 h and 60 days (37ºC) and, aft er each storage period, they were subjected to the microhardness test using a Vickers indenter during 45 s using a 50 g load. The results (VHN) were subjected to stati sti cal analysis by ANOVA and Tukey's test (α=0.05). Results: In the 24-hour period, the mean values (±SD) presented by the tested resins were: Filtek Z250-64.46 (±3.30); Filtek Z350-59.60 (±3.42); and Durafi ll-21.69 (±2.39). Aft er 60-day storage, the mean values (±SD) presented by the tested resins were: Filtek Z250-71.07 (±6.38); Filtek Z350-47.63 (±4.42); and Durafi ll-23.72 (±3.50). There was stati sti cally signifi cant diff erence between groups II, III, V and VI (p<0.005). However, groups I and II did not diff er signifi cantly from each other, but were signifi cantly diff erent from the other groups. Conclusion: The storage in disti lled water and the size of the load parti cles can have infl uence on the surface microhardness of estheti c composite resins.

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Objective: To evaluate the influence of alternative photoinitiators present in composite resins related to yellowing, color stability, photosensitivity, light-curing efficiency, degree of conversion, and microhardness. Materials and methods: The literature was reviewed by two independent reviewers at PubMed. The search strategy was carried out using the following descriptors: (Photoinitiators, dental) AND (Curing lights, dental) AND (Composite Resins) NOT (Case report). The electronic search was carried out until March 2019, without language restrictions, and inclusion and exclusion criteria were applied in the selection. Results: Thirteen articles met the previously established criteria, and all were included. Of these, most were in vitro studies. After the aging of the composite, all systems suffered yellowing, however the isolates with camphorquinone were the most affected and, although there is a greater tendency to yellowing, this does not directly affect color stability. However, the literature is still conflicting about which system has significant color stability. Regarding photosensitivity, all photoinitiators have different absorption peaks. In this sense, the photopolymerization must be chosen with caution, as the conversion of monomers and microhardness proved to be directly linked to the correct combination of photoactivator and photopolymerizing unit. Conclusion: Alternative photoinitiators have a lower yellowing rate and good color stability. They can be up to five times more sensitive than systems containing isolated camphorquinone. Only third-generation light-emitting diodes photopolymerize satisfactorily composite resins that have alternative photoinitiators in their composition, ensuring a good degree of conversion and acceptable Knoop microhardness values.

AIM: Conducting a systematic review of randomized clinical trials focusing on the efficacy of LLLT on pain control in patients with TMD, diagnosed by the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). MATERIAL AND METHODS: Search was performed at PubMed/MEDLINE database with the terms: (1) “Laser AND temporomandibular disorders”; (2) “Laser AND temporomandibular disorders AND RDC/TMD”; (3) “Low-level laser therapy AND temporomandibular disorders”; (4) “Low-level laser therapy AND temporomandibular disorders AND RDC/TMD”; (5) “Low-level laser therapy AND temporomandibular joint dysfuntion syndrome”; (6) “Low-level laser therapy AND temporomandibular joint dysfuntion syndrome AND RDC/TMD”; (7) “Laser AND temporomandibular joint dysfuntion syndrome” (8) “Laser AND RDC/TMD”; (9) “Low-level laser therapy AND RDC/TMD”. Inclusion criteria: articles need to be randomized clinical trial performed in humans; evaluate the effect of LLLT in the treatment of TMD diagnosed by the use of RDC/TMD; published in English or Portuguese in the last 10 years. Protocol studies and pilot studies were excluded. RESULTS: Ten studies were included. The type of laser used was Gallium Aluminum Arsenide (GaAlAs) diode, with exception of 1 paper, which used super pulsed Gallium Arsenide laser. Eight studies reported decreased in pain levels, in two articles there was no statistically significant difference between test and placebo groups. CONCLUSION: In most studies, LLLT was effective in pain remission, but there is no standardization in parameters like wavelength, output power and frequency. Studies with more complex experimental designs, standardized diagnostic criteria for TMD and defined protocols for the use of LLLT are needed to determine its efficacy in the treatment of TMD.