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Purpose: To compare the effect of thermal cycling and erosive challenge on color change, surface roughness, surface loss and biofilm deposition of three resin-based composites., Methods: Three resin-based composites that reproduce the color of gingival tissues [two nanohybrid composites (A and B) and a giomer (C) ] were tested before and after distinct challenges [ thermal cycling (TC) and erosive challenge (EC) ] in regard to its color stability, surface roughness, surface loss and biofilm deposition. Surface roughness and surface loss specimens (n=10) were measured with an optical profilometer and, color stability (n=10) was measured with a spectrophotometer. Biofilm deposition (n=5) was measured after 3 and 24 hours by safranin staining., Results: Two-way ANOVA test was performed to analyze color change, roughness and surface loss. A significant color change was detected for resin-based composites (P< 0.05) and its interaction with tested challenges (P< 0.05). The highest color variation was observed on the giomer after erosive challenge. Surface loss was not different between tested groups (P= 0.708). The roughness was significantly higher in specimens submitted to thermal cycling (P> 0.05). For biofilm quantification, after 3 and 24 hours, ANOVA (3-way) detected significance for the interaction of challenges and resin-based composites (P< 0.05 and P< 0.05, respectively). All resin-based composites presented color changes after challenges; higher roughness was observed after thermal cycling for all resin-based composites tested, without significant surface loss; and higher biofilm deposition was observed on the giomer samples when submitted to erosive challenge after 3 and 24 hours., Clinical Significance: Pink esthetic is as important as dental esthetics and some restorative materials can mimic gingival tissue. However, the tested giomer must be indicated with caution, since it presented significant changes after thermal and acid challenges., Competing Interests: The authors did not have any financial interest in the companies of which materials are included in this article. This study was supported by the National Council of Technological and Scientific Develop-ment, CNPq (Grants: 155284/2016-9) and São Paulo Research Foundation, FAPESP (Process number: 2015/13571-1)., (Copyright©American Journal of Dentistry.)

The aim of this study was to evaluate the influence of finishing and polishing systems and toothbrush abrasion on transmittance (T) and surface roughness (Ra) of three composite resins (Filtek Z350 XT, Tetric N-Ceram, and IPS Empress Direct). Eighteen resin disks (10 mm diameter × 2 mm thick) finished by polyester strips had initial surface smoothness recorded, representing phase 1 (P1). Specimens were divided into three groups (n=6) according to the finishing/polishing instrument used (OneGloss, TopGloss, and Sof-Lex) to compose phase 2 samples (P2). Then specimens were subjected to 514 cycles of toothbrush simulation using a toothpaste slurry, with a constant load applied to soft bristles, and were then washed (phase 3=P3). After each phase, the specimens were examined by an optical profiler and spectrophotometer to measure Ra and T. Data were analyzed by analysis of variance, Tukey and Pearson tests. T values were statistically influenced by composite resin ( p=0.000) and phase of measurement ( p=0.000) factors, while the finishing/polishing system used ( p=0.741) did not affect T. On the other hand, Ra values were statistically affected by the factor finishing/polishing system ( p=0.000), but not by composite resin ( p=0.100) and phase of measurement ( p=0.451). Tetric N-Ceram and Empress Direct presented higher values of roughness when polished by OneGloss, while TopGloss and Sof-Lex showed a lower roughness. It can be concluded that composite resins transmitted more light after dental abrasion. Transmittance of composite resins was not modified by the distinct roughness created by finishing/polishing instruments.

This study evaluated the influence of the irradiation with a short-pulse Er:YAG laser on the adhesion of composite resin to sound and eroded dentin (SD and ED). Forty-six samples of occlusal dentine, obtained from human molars, had half of their surface protected, while the other half was submitted to erosive cycles. Afterward, 23 samples were irradiated with Er:YAG laser, resulting in four experimental groups: SD, sound irradiated dentine (SID—Er:YAG, 50  μs 50  μs , 2 Hz, 80 mJ, and 12.6  J/cm 2 12.6  J/cm2 ), ED, and eroded irradiated dentin (EID—erosion + Er:YAG laser). A self-etching adhesive system was used, and then cylinders of composite resin were prepared. A microshear bond strength test was performed after 24 h storage (n=20 n=20 ). The morphology of SD and ED, with or without Er:YAG laser irradiation, was evaluated under scanning electron microscopy (n=3 n=3 ). Bond strength values (MPa) were subjected to analysis of variance followed by Tukey’s test. Statistically significant differences were found among the experimental groups: SD (9.76±3.39  B 9.76±3.39  B ), SID (12.77±5.09 A 12.77±5.09 A ), ED (5.12±1.72 D 5.12±1.72 D ), and EID (7.62±3.39 C 7.62±3.39 C ). Even though erosion reduces the adhesion to dentin, the surface irradiation with a short-pulse Er:YAG laser increases adhesion to both ED and SD.

Purpose: The objective of this in vitro study was to compare the degree of microleakage of composite restorations performed by lasers and conventional drills associated with two adhesive systems., Materials and Methods: Sixty bovine teeth were divided into 6 groups (n = 10). The preparations were performed in groups 1 and 2 with a high-speed drill (HD), in groups 3 and 5 with Er:YAG laser, and in groups 4 and 6 with Er,Cr:YSGG laser. The specimens were restored with resin composite associated with an etch-and-rinse two-step adhesive system (Single Bond 2 [SB]) (groups 1, 3, 4) and a self-etching adhesive (One-Up Bond F [OB]) (groups 2, 5, 6). After storage, the specimens were polished, thermocycled, immersed in 50% silver nitrate tracer solution, and then sectioned longitudinally. The specimens were placed under a stereomicroscope (25X) and digital images were obtained. These were evaluated by three blinded evaluators who assigned a microleakage score (0 to 3). The original data were submitted to Kruskal-Wallis and Mann-Whitney statistical tests., Results: The occlusal/enamel margins demonstrated no differences in microleakage for all treatments (p > 0.05). The gingival/dentin margins presented similar microleakage in cavities prepared with Er:YAG, Er,Cr:YSGG, and HD using the etch-and-rinse two-step adhesive system (SB) (p > 0.05); otherwise, both Er:YAG and Er,Cr:YSGG lasers demonstrated lower microleakage scores with OB than SB adhesive (p < 0.05)., Conclusion: The microleakage score at gingival margins is dependent on the interaction of the hard tissue removal tool and the adhesive system used. The self-etching adhesive system had a lower microleakage score at dentin margins for cavities prepared with Er:YAG and Er,Cr:YSGG than the etch-and-rinse two-step adhesive system.

Aim: The aim of this study was to evaluate how cavity preparation and primer application methods influence the adhesion of composite resin to dentin using a self-etching system., Methods and Materials: Forty-eight extracted, sound human molars were divided into six groups (n=8) according to the method used for the surface preparation of the teeth (#600-grit paper disc, diamond bur, and Er:YAG laser) and the primer application method utilized (active or passive). Following the adhesive procedure using a self-etching system, 5 mm high composite buildups were created with Z-250 composite resin. After storage in water at 37 degrees C for 24 hours, the specimens were vertically sectioned into serial 1 mm2 sticks and tested for microtensile strength (micro-TBS). Nine additional molars were prepared for morphological analysis using scanning electron microscopy (SEM)., Results: Statistical analysis showed surface preparation technique (p < 0.00) and primer application methods (p < 0.001) do influence bond strength of the self-etching system tested. The best adhesion was achieved with specimens having the dentin ground with sandpaper followed by those ground with diamond burs. The worst bonding was obtained with Er:YAG laser ablated dentin. The active primer application method increased bonding performance compared to the passive method., Conclusions: Within the limitations of the study, it can be stated surface treatment can influence the bond strength of the self-etching system tested and the active primer application method is more effective in achieving success in bonding to dentin compared with the passive application method., Clinical Significance: Clinicians should use the active application method to apply a mild acidic self-etching primer along with an appropriate tooth surface preparation to facilitate the bond strength between dentin and composite resin.

Aim: The aim of this study was to evaluate the influence of chlorhexidine on microleakage of composite restorations in class V cavities prepared with a carbide bur (CB) and a erbium:yttrium-aluminum-garnet (Er:YAG) laser., Methods and Materials: Cavity preparations were created on the buccal surfaces of 48 bovine incisors using different methods then equally dividing them into four groups. Groups I and II were prepared with a #56 CB in a high speed handpiece while Groups III and IV were prepared with a Er:YAG laser at 350m J/4Hz on enamel and at 80.24 J/cm2 on dentin. The cavity preparations were rinsed with 2% chlorhexidine solution before the application of Clearfill SE Bond system and placement of a Z100 composite resin restoration. After 24 hours, the teeth were polished, thermocycled, and sealed with cosmetic varnish. The samples were then immersed in 2% methylene blue for four hours and sectioned in the buccolingual direction to determine the degree of microleakage., Results: After statistical analysis (Kruskal-Wallis, p<0.05), no significant differences were verified among the tested groups and between the evaluated cervical or incisal margins of the restoration., Conclusion: The use of the chlorhexidine did not interfere with the adhesion process regardless of whether a CB or the Er:YAG laser were used to prepare class V cavities when restored with the tested self-etching adhesive system.

Objective: The purpose of this research was to evaluate Nd:YAG laser influence on microleakage of class V composite restorations., Background Data: There are few studies concerning laser with restorative materials, considering microleakage. One more sent., Methods: Thirty six cavities were prepared and divided into three groups (n = 12): group 1, control; group 2, Nd:YAG laser irradiation before adhesive technique; group 3, Nd:YAG laser irradiation after adhesive technique was used as the single bottle. Adhesive system Nd:YAG laser parameters were 320 microm of fiberoptic; energy/pulse of 40 mJ of energy/pulse; repetition rate of 15 Hz; power of 0.6 W; pulsed and non-contact, 1 mm from the surface; 30 seconds in scanning mode; energy density was 49.76 J/cm(2). Cavities were restored with microhybrid composite. After having used a polishing technique, thermocycling and impermeabilization procedures were performed and specimens were submitted to a microleakage test consisting of immersion in aqueous solution of 50% silver nitrate for 8 h, in the total absence of light. After washing and drying procedures, teeth were embedded to facilitate buccal-lingual vertical sectioning. Microleakage was revealed by light., Results: We accomplished Kruskal-Wallis test at 5% level of confidence and observed no statistically significant difference between the tested groups., Conclusions: Based on the obtained results, it was possible to conclude that Nd:YAG laser in the parameters used, has no influence on marginal microleakage in composite restorations, independent of the moment the laser was used.

Purpose: To evaluate the influence of air-particle abrasion and treatments on in vitro tensile bond strength of resin composite bonded to human enamel was evaluated using a single-bottle adhesive., Methods: Human teeth were divided into 12 groups of three treatments (none, 27-microm Al2O3 air-particle abrasion, 50-microm Al2O3 air-particle abrasion) and four conditioners [none, phosphoric acid (PA), NRC (no-rinse conditioner), and PA/NRC]. Bonding agent (Prime & Bond NT) and a resin composite (TPH Spectrum) were applied as inverted cones. Specimens were stored for 24 hours at 37 degrees C and debonded in tension using a testing machine at 0.5 mm/minute., Results: Phosphoric acid treatment used with Prime & Bond NT produced the best bond strengths (24 MPa) to enamel for surfaces treated with 27-microm air-particle abrasion and for surfaces not treated with air-particle abrasion (control). With one exception, air-particle abraded surfaces resulted in bond strengths between 9 to 16 MPa. NRC with or without the use of phosphoric acid in general did not improve tensile bond strength to enamel when compared to surfaces not treated with NRC.

Objective: The purpose of this research was to evaluate the influence of the Nd:YAG laser on microleakage of class V composite restorations., Background Data: There has been very little research that concerns microleakage resulting from the use of lasers and restorative materials., Materials and Methods: Thirty-six cavities were prepared and divided into three groups (n = 12) as follows: Group 1, control; Group 2, Nd:YAG laser irradiation before adhesive technique; Group 3, Nd:YAG laser irradiation after adhesive technique. Nd:YAG laser parameters were 320 micro m of fiberoptics; energy/pulse of 40 mJ of energy/pulse; repetition rate of 15 Hz; power of 0.6 W; pulsed and non-contact, 1 mm from the surface; 30 sec in scanning mode; energy density was 49,76 J/cm(2). Cavities were restored with microhybrid composite. After polishing, thermocycling and impermeabilization procedures were performed and specimens were submitted to a microleakage test, with complete immersion in aqueous solution of 50% silver nitrate for 8 h, in the total absence of light. After washing and drying, teeth were embedded to facilitate buccal-lingual vertical sectioning. Microleakage was revealed by light., Results: We used the Kruskal-Wallis test at a 5% level of confidence and observed no statistically significant difference among the tested groups., Conclusion: It was possible to conclude that Nd:YAG laser does not influence marginal microleakage on composite restorations, independent of the moment the laser had been used.

The aim of this in vitro study was to compare the tensile bond strength of 3 different bonding systems, associated to composite resins, bonded to dentinal surfaces. Forty-four dentinal surfaces were obtained from recently extracted human molars. A standardized smear layer was obtained and the surfaces were divided in 3 groups: G1) self etch + microhybrid composite; G2) single-component adhesive + phosphoric acid + microhybrid composite and G3) conventional system (acid + primer + bond) + microhybrid composite. Specimens made of composite resin were constructed in the shape of an inverted truncated cone with 3 mm of diameter. Tensile bond strength test was performed at the speed of 0.5 mm/min, and the results were expressed in MPa. The analysis of variance ANOVA (p < 0.05) determined that the type of bonding system used influenced tensile bond strength. Tukey's test, however, showed that the results of the comparison between G2 and G3 were the only statistically significant ones, with G2 showing greater values of tensile bond strength.

Purpose: To evaluate dye penetration of proximal vertical slot resin-based composite (RBC) restorations as a function of cavity size and restorative material employed (RBC, ceramic inserts with low-viscosity resin, and RBC with low-viscosity resin liner). Microleakage was measured using rank scoring and linear measurement of dye penetration and ANOVA and non-parametric tests were used to evaluate the statistical significance of the results., Materials and Methods: Ninety erupted crack- and caries-free mandibular third molars, extracted for orthodontic reasons, were used. Proximal vertical slots were prepared on the mesial surfaces of the teeth using diamond instruments at high speed under distilled water coolant. Teeth were placed randomly into nine groups. Three sizes of diamond burs of an ultrasonic cavity preparation system were used under low energy in order to standardize cavity size and shape, each tip size being used in 30 different teeth. The gingival margins were prepared 1 mm above the cemento-enamel junction. Specimens were etched, prepared with bonding agent, restored using three different materials, and immersed in a 50% AgNO3 solution for 8 hrs and sectioned to evaluate the dye penetration., Results: Statistical analysis revealed no statistically significant differences among the nine groups.

Objective: We evaluated the tensile bond strength of composite resin on enamel and dentine, treated with Nd:YAG laser before and after bonding procedures., Background Data: The use of laser radiation in dentistry is being developed day by day. One of the possible applications of dental lasers includes increasing the quality of self-etching bonding systems., Methods: Forty-eight human teeth were used and separated into six groups: Group 1 (enamel control), Clearfil Liner Bond 2V (CLB 2V); group 2 (enamel), Nd:YAG + CLB 2V; group 3 (enamel), CLB 2V + Nd:YAG; group 4 (dentine control), CLB 2V; group 5 (dentine), Nd:YAG + CLB 2V; group 6 (dentine), CLB 2V + Nd:YAG. Tensile bond strength was performed., Results: Enamel means (15,54) were lower than dentine means (20,38). Bond strength of laser before (15,73) was lower than laser after (20,65). Interaction results G1 x G3; G2 x G3; G4 x G1; G2 x G5 were statistically significant., Conclusions: Tensile bond strength of composites reached with self-etching adhesive systems were greater in dentine than in enamel. The best moment for application of Nd:YAG laser is after the use of adhesive system. Self-etching adhesive systems tested in this study can be used together with Nd:YAG laser without compromising to adhesion to dentine.

Objective: This study evaluated microleakage of composite restorations submitted to marginal treatment with Nd:YAG laser and surface sealant., Background Data: Previous studies have demonstrated that Nd:YAG-lased enamel melted and became recrystallized with a morphologic appearance similar to lava, and has been used clinically in the sealing of enamel pits and fissures., Methods: Class V cavities in enamel of human premolars were restored with composite resin (Z100, 3M) and randomly divided in six groups: G1, control; G2, surface sealant marginal treatment; G3 to G6, were treated with pulsed Nd:YAG laser (1.064 microm) marginal treatment, contact fiberoptic (300 microm), air cooling, for 30 seconds, powers of 1.2-2 W, repetition rates of 20-30 Hz, energies of 40-100 mJ. Teeth were impermeabilized, immersed in a rhodamine dye, sectioned, and evaluated under stereomicroscope microscopy with scores., Results: There were significant differences between marginal treatments; there were no differences between groups 1, 2, and 4, and 3,5, and 6; lower values of microleakage were at groups 3, 5, and 6 (Kruskal-Wallis,p = 0.05)., Conclusion: Nd:YAG laser showed improved marginal sealing and decreased microleakage of composite resins restorations.

Purpose: To compare the in vitro tensile bond strengths of resin-based composite bonded to dentin and to a leucite-reinforced ceramic in an as-received condition (pre-silanated) or re-etched, re-silanated condition., Materials and Methods: Caries-free human molars were ground to expose occlusal, superficial dentin. Dentin surfaces were etched with 37% phosphoric acid and rinsed, leaving a moist dentin surface. Leucite-reinforced ceramic inserts (SONICsys) also were tested as received (pre-etched, pre-silanated) or retreated with hydrofluoric acid and silane. Bonding agent (Syntac Single-Component) was applied in two layers and light cured. An all-purpose resin-based composite (Tetric Ceram) was used to prepare tensile bond strength specimens for the dentin and two ceramic groups. Fourteen specimens were prepared for each group. After 24 hours in distilled water, tensile bond strength (MPa) was measured using a testing machine. Analysis of variance was used to evaluate data., Results: Bond strengths obtained were 10.2 MPa for composite bonded to dentin, 10.5 MPa for composite bonded to as-received ceramic inserts, and 9.6 MPa for composite bonded to retreated ceramic inserts, with no statistical difference between the three groups. Re-treatment of leucite-reinforced inserts did not increase or decrease bond strength to resin-based composite. Also, the bond strength of resin-based composite to dentin was similar to that of the ceramic to composite.