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.

Dentin adhesion procedure presents limitations, especially regarding to lifetime stability of formed hybrid layer. Alternative procedures have been studied in order to improve adhesion to dentin. Objective: The aim of this study was to evaluate in vitro the influence of deproteinization or dentin tubular occlusion, as well as the combination of both techniques, on microtensile bond strength μTBS) and marginal microleakage of composite resin restorations. Material and Methods: Extracted erupted human third molars were randomly divided into 4 groups. Dentin surfaces were treated with one of the following procedures: (A) 35% phosphoric acid gel (PA) + adhesive system (AS); (B) PA + 10% NaOCl + AS; (C) PA + oxalate + AS and (D) PA + oxalate + 10% NaOCl + AS. Bond strength data were analyzed statistically by two-way ANOVA and Tukey's test. The microleakage scores were analyzed using Kruskal-Wallis and Mann-Whitney non-parametric tests. Significance level was set at 0.05 for all analyses. Results: μTBS data presented statistically lower values for groups D and B, ranking data as A>C>B>D. The use of oxalic acid resulted in microleakage reduction along the tooth/restoration interface, being significant when used alone. On the other hand, the use of 10% NaOCl alone or in combination with oxalic acid, resulted in increased microleakage. Conclusions: Dentin deproteinization with 10% NaOCl or in combination with oxalate significantly compromised both the adhesive bond strength and the microleakage at interface. Tubular occlusion prior to adhesive system application seems to be a useful technique to reduce marginal microleakage.

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The objective of this study was to evaluate in vitro the roughness and surface morphology of composite resins (CRs) stored for 180 days in acidic solutions present in the diet. Three micro-hybrid composite resins were used in this study (Charisma, Opallis, and Esthet-X). Fifty-one specimens were made of each material with 4 mm in diameter and 2 mm thick with the aid of an elastomer matrix. After photoactivation for 40 seconds (Elipar Free-Light / 3M ESPE), the specimens were stored in distilled water for 24 hours at 37ºC for subsequent surface polishing with Soft Lex / 3M ESPE discs in fine and extra-fine granulation. Then, the specimens were dried with absorbent paper and the surface roughness was measured using a rugosimeter. The specimens were then randomly divided into five groups (n=10) according to the tested solutions: DW - Distilled water (pH 5.30); RW - Red Wine / Trapiche Syha Ind. Argentina red wine (pH 3.68); CK – Coke / Coca Cola Co. (pH 2.73), OJ - Orange juice / Purity Cocamar (pH 3.58) and LBS - lactate buffer solution (pH 2.74). The tested solutions were changed daily. The surface roughness test was repeated after 15, 90 and 180 days of immersion. The average values of surface roughness were submitted to LSmeans analysis and Tukey-Kramer test, at a significance level of 5%. The results of surface roughness revealed that all CRs showed a significant increase in the roughness values over time for all tested solutions.