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This study evaluated color change, stability, and tooth sensitivity in patients submitted to different bleaching techniques.Material and methodsIn this study, 48 patients were divided into five groups. A half-mouth design was conducted to compare two in-office bleaching techniques (with and without light activation): G1: 35% hydrogen peroxide (HP) (Lase Peroxide - DMC Equipments, São Carlos, SP, Brazil) + hybrid light (HL) (LED/Diode Laser, Whitening Lase II DMC Equipments, São Carlos, SP, Brazil); G2: 35% HP; G3: 38% HP (X-traBoost - Ultradent, South Jordan UT, USA) + HL; G4: 38% HP; and G5: 15% carbamide peroxide (CP) (Opalescence PF - Ultradent, South Jordan UT, USA). For G1 and G3, HP was applied on the enamel surface for 3 consecutive applications activated by HL. Each application included 3x3' HL activations with 1' between each interval; for G2 and G4, HP was applied 3x15' with 15' between intervals; and for G5, 15% CP was applied for 120'/10 days at home. A spectrophotometer was used to measure color change before the treatment and after 24 h, 1 week, 1, 6, 12, 18 and 24 months. A VAS questionnaire was used to evaluate tooth sensitivity before the treatment, immediately following treatment, 24 h after and finally 1 week after. ResultsStatistical analysis did not reveal any significant differences between in-office bleaching with or without HL activation related to effectiveness; nevertheless the time required was less with HL. Statistical differences were observed between the results after 24 h, 1 week and 1, 6, 12, 18 and 24 months (intergroup). Immediately, in-office bleaching increased tooth sensitivity. The groups activated with HL required less application time with gel. ConclusionAll techniques and bleaching agents used were effective and demonstrated similar behaviors.

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Direct composite resin restorations have become a viable alternative for patients that require anterior restorative procedures to be integrated to the other teeth that compose the smile, especially for presenting satisfactory esthetic results and minimum wear of the dental structure. Technological evolution along with a better understanding of the behavior of dental tissues to light incidence has allowed the development of new composite resins with better mechanical and optical properties, making possible a more artistic approach for anterior restorations. The combination of the increasing demand of patients for esthetics and the capacity to preserve the dental structure resulted in the development of different incremental techniques for restoring fractured anterior teeth in a natural way. In order to achieve esthetic excellence, dentists should understand and apply artistic and scientific principles when choosing color of restorative materials, as well as during the insertion of the composite resin. The discussion of these strategies will be divided into two papers. In this paper, the criteria for color and material selection to obtain a natural reproduction of the lost dental structures and an imperceptible restoration will be addressed.

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ObjectivesNanofilled composite resins are claimed to provide superior mechanical properties compared with microhybrid resins. Thus, the aim of this study was to compare nanofilled with microhybrid composite resins. The null hypothesis was that the size and the distribution of fillers do not influence the mechanical properties of surface roughness and wear after simulated toothbrushing test. Material and methodsTen rectangular specimens (15 mm x 5 mm x 4 mm) of Filtek Z250 (FZ2), Admira (A), TPH3 (T),Esthet-X (EX), Estelite Sigma (ES), Concept Advanced (C), Grandio (G) and Filtek Z350 (F) were prepared according to manufacturer's instructions. Half of each top surface was protected with nail polish as control surface (not brushed) while the other half was assessed with five random readings using a roughness tester (Ra). Following, the specimens were abraded by simulated toothbrushing with soft toothbrushes and slurry comprised of 2:1 water and dentifrice (w/w). 100,000 strokes were performed and the brushed surfaces were re-analyzed. Nail polish layers were removed from the specimens so that the roughness (Ra) and the wear could be assessed with three random readings (µm). Data were analyzed by ANOVA and Tukey's multiple-comparison test (α=0.05). ResultsOverall outcomes indicated that composite resins showed a significant increase in roughness after simulated toothbrushing, except for Grandio, which presented a smoother surface. Generally, wear of nanofilled resins was significantly lower compared with microhybrid resins. ConclusionsAs restorative materials suffer alterations under mechanical challenges, such as toothbrushing, the use of nanofilled materials seem to be more resistant than microhybrid composite resins, being less prone to be rougher and worn.

ABSTRACT:The purpose of this study was to measure mass loss and surface roughness changes of different brands of flowable resin composites after a simulated toothbrushing test. The null hypotheses were that there would be no differences in mass loss and no significant changes in surface roughness after this test and that there would be no correlation between the two variables. The tested materials were Aeliteflo (Bisco), Flow-It (Pentron), Flow-It LF (Pentron), Natural Flow (DFL) and Wave (SDI). Z100 (3M/ESPE) microhybrid and Silux Plus (3M/ESPE) microfilled resin composites were used as control materials. Twelve specimens (5 mm in diameter, 3 mm thick) of each material were prepared according to manufacturers' instructions. Toothbrushing abrasion was performed on all specimens from each of the materials using a simulator. The percentage mass loss and surface roughness were assessed before and after 100,000 brushstrokes, using a Sartorius analytical balance of 0.0001 g accuracy and a Hommel Tester T1000, respectively. The measurements of both properties were statistically compared by paired t-test and Tukey's test (p < 0.05). All materials presented a statistically significant mass loss comparing initial and final values, with the exception of Flow-It LF. However, no difference was revealed when comparing the mass loss of the different tested materials. All materials became rougher and Wave presented statistically higher roughness compared to the other resin composites. Flowable resin composites did not seem to be superior to the control groups, and they can be expected to wear by mass loss and to have an increased roughness of surface after toothbrushing action. The anticipated null hypotheses were partially accepted. DESCRIPTORS: Composite resins; Tooth abrasion; Surface properties; Toothbrushing. RESUMO:O objetivo deste estudo foi mensurar a perda de massa e as alterações de rugosidade superficial de diferentes marcas de resinas compostas "flow" após teste de escovação simulada. A hipótese nula testada foi de que não haveria diferença de massa e rugosidade de superfície após o teste e de que não haveria correlação entre essas variáveis. Os materiais testados foram: Aeliteflo (Bisco), Flow-It (Pentron), Flow-It LF (Pentron), Natural Flow (DFL) e Wave (SDI). As resinas compostas Z100 (3M/ESPE) e Silux Plus (3M/ESPE) foram utilizadas como controle. Doze espécimes (5 mm de diâmetro, 3 mm de espessura) de cada material foram confeccionados de acordo com as instruções do fabricante. O teste foi conduzido em uma máquina de escovação simulada, em todos os espécimes de todos os materiais, totalizando 100.000 ciclos. Antes e depois do teste, a massa e a rugosidade de cada material foram aferidas por uma balança analítica Sartorius de 0,0001 g de precisão e pelo equipamento Hommel Tester T1000, respectivamente. Os valores obtidos foram comparados pelos testes t-pareado e Tukey (p < 0,05). Todos os materiais apresentaram diferenças estatísticas de perda de massa entre os valores iniciais e finais, com exceção da resina F...