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The objective of this longitudinal clinical randomized trial was to evaluate the clinical performance of a nanofilled and a nanohybrid resin composite in Class I occlusal restorations of posterior teeth over the course of 54 months. Forty-one adolescents participated in the study. The teeth were restored with Adper Single Bond 2 (3M ESPE) and nanofilled (Filtek Z350, 3M ESPE), nanohybrid (Esthet-X, Dentsply) and microhybrid Filtek Z250 (3M ESPE) used as a control. After 54 months, the restorations were evaluated in accordance with the modified United States Public Health Service criteria. The McNemar and Friedman tests were used for statistical analysis, at a level of significance of 5%. Five failed restorations were observed during the follow-up. A change to unacceptable restoration occurred for one Esthet-X, two Filtek Z350, and two Filtek Z250 restorations, which received the clinically unacceptable score, Charlie, for both anatomic form and marginal adaptation. Secondary caries and postoperative sensitivity occurred in one Filtek Z250 and one Filtek Z350 restoration. When the five evaluation periods (baseline and six, 12, 30, and 54 months) were compared, significant differences were found in the marginal adaptation of Filtek Z250 and Filtek Z350. Significant differences in the roughness criteria (p =0.005) were also observed when the three composites were compared after 54 months (Filtek Z350 > Filtek Z250 > Esthet-X), always within clinically acceptable limits. The materials investigated showed acceptable clinical performance for Class I restoration after 54 months. Long-term reevaluations are necessary for a more detailed analysis of these composites. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the bond durability of dentin restorations bonded with light-or dual-cured etch-and-rinse adhesive systems. A three-step adhesive system (Scotchbond Multipurpose Plus), an acetone-based two-step adhesive system (Prime & Bond 2.1), and an ethanol-based two-step adhesive system (Excite) were tested. Both the light- and the dual- cured versions were evaluated. High C-factor dentin cavities were prepared on 120 bovine incisors, which were then restored with resin composite (n=10). The samples were stored in water for 24 hours, and half of them were subjected to additional degradation with 10% NaOC1 for five hours. The push-out bond strength test was performed in a universal testing machine until failure. Failure modes were evaluated by scanning electron microscopy. Data were analyzed by three-way analysis of variance and Tukey tests (p<0.05). The dual-cured adhesive system presented a higher immediate bond strength and durability than those that were light cured. The three-step adhesive system produced the highest values, whereas the acetone-based adhesive system produced the lowest result. Therefore, the use of dual-cured etch-and-rinse adhesive systems can induce increased bond durability to direct coronal dentin restorations. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of five methods of solvent volatilization on the degree of con- version (DC) of nine one-bottle adhesive systems using Fourier transform infrared/ attenuated total reflectance (FTIR/ATR) analysis. Nine adhesives were tested: Adper Single Bond 2 (SB), Adper Easy One (EO), One Up Bond F Plus (OUP), One Coat Bond SL (OC), XP Bond (XP), Ambar (AM), Natural Bond (NB), GO, and Stae. The adhesive systems were applied to a zinc-selenide pellet and 1) cured without solvent volatilization, 2) left undisturbed for 10 seconds before curing, 3) left undisturbed for 60 seconds before curing, 4) air-dried with an air stream for 10 seconds before curing, and 5) air-dried with an air stream for 60 seconds before curing. FTIR/ATR spectra were obtained, and the DC was calculated by comparing the aliphatic bonds/reference peaks before and after light activation for 10 seconds (FlashLite 1401). The DC means of each material were analyzed by one-way analysis of variance and post hoc Tukey test (p<0.05). The DC of GO and Stae adhesive systems was not affected by the five evaporation conditions. Air-drying for 60 seconds before curing yielded the highest DC for SB, EO, and OC. Extended solvent volatilization time (60 seconds) either with or without air-drying before curing provided the highest DC for AM, NB, XP, and OUP. Thus, the monomer conversion of adhesive systems was material dependent. In general, the 60-second passive or active air-drying modes to volatilize solvents before curing enhanced the degree of conversion for the one-bottle simplified adhesive systems. [ABSTRACT FROM AUTHOR]

This study was designed to evaluate in vitro the efficacy of a novel at-home bleaching technique using 10% or 16% carbamide peroxide modified by casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and its influence on the microhardness of bleached enamel. A total of 40 bovine incisors were divided into four groups (n-10) according to the bleaching agent used: 10% carbamide peroxide only; a blend of 10% carbamide peroxide and a CPP-ACP paste; 16% carbamide peroxide only; and a blend of 16% carbamide peroxide and a CPP-ACP paste. During the 14-day bleaching regimen, the samples were stored in artificial saliva. The Vickers microhardness and color of the teeth were assessed at baseline (TO) and immediately after the bleaching regimen (T14) using a microhardness tester and a spectrophotometer, respectively. The degree of color change was determined by the Commission Internationale de l'Eclariage (CIE) L*a*b* system (ΔE, ΔL*, Δa*, and Δb*) and Vita shade guide parameters. The data were analyzed by analysis of variance and the Tukey test (p<0.05). The teeth that were bleached with a blend of peroxide (10% or 16%) and the CPP-ACP paste presented increased microhardness values at T14 compared with TO, whereas the samples that were bleached with peroxide only did not show any differences in their microhardness values. All of the bleaching agents were effective at whitening the teeth and did not show a statistically significant difference using the CIEL*a*b* system (ΔE, ΔL*, Δa*, and Δb*) or the Vita shade guide parameters. The use of a CPP-ACP paste with carbamide peroxide bleaching agents increased the bleached enamel's microhardness and did not have an influence on whitening efficacy. [ABSTRACT FROM AUTHOR]

This in vitro study morphologically evaluated the effect of some current surface pre-treatments on dentin, using scanning electron microscopy, and related these morphological alterations to clinical implications. The labial surfaces of 30 bovine lower incisors were ground to obtain a flat dentin surface and were finished with 600-grit SiC paper to produce standardized smear layers. The teeth were randomly divided into six groups of five each. Group 1 was the control group, smear layer covered dentin; Group 2 was etched with 37% phosphoric acid (PA) for 15 seconds; Group 3, 37% PA for 15 seconds, followed by 10% NaOCl for 60 seconds; Group 4, 10% NaOCl for 60 seconds; Group 5, a self-etching primer (Clearfil SE Bond, CSEB-primer) was applied for 20 seconds; Group 6, CSEB-primer for 20 seconds, followed by NaOCl for 60 seconds. The specimens were fixed, dehydrated, dried and analyzed by SEM. Treatment with 37% PA removed the smear layer, funneled the tubules and resulted in a collagen-rich surface which appeared to have collapsed in its outermost part, producing a dense surface layer covered with silica particles. When 37% PA treatment was followed by 10% NaOCl, the collagen network was removed to reveal an eroded, rough mineral surface with numerous lateral branches and larger than normal tubular orifices. The action of 10% NaOC1 on the smear layer-covered dentin showed no significant alteration in surface morphology. The treatment with CSEB-primer dissolved the smear layer but only partially dissolved the smear plugs. The tubules did not present the typical funnel shape seen following PA treatment. These morphological aspects on dentin surface must influence bonding results. The dentin surface alterations produced by PA appeared to he a very severe demineralization pattern, quite irregular and less permeable to monomer infiltration, while the surface provided by the self-etching primer appeared to be a more uniform, less porous surface, and the association with simultaneous monomer infiltration may reduce the occurrence of mistakes in clinical bonding procedures. [ABSTRACT FROM AUTHOR]

The study evaluated the influence of collagen removal and the use of a low-viscosity liner on the marginal quality of composite restorations for the total-etch system, Prime & Bond 2.1 (PB) and the self-etching primer system, Clearfil SE Bond (CSEB), in high C-factor cavities with margins in dentin. High C-factor cavities were made on dentin exposed from ground labial surfaces of 100 bovine lower incisors, randomly assigned to 10 treatment groups and restored with composite Z 250, placed in bulk. In Group 1 (PB), control group, PB was applied according to the manufacturer's directions; in Group 2 (PB/SH) following acid-etching, the surfaces were treated with 10% sodium hypochlorite (SH) for one minute and in Group 4 (PB/SH/PLF), the same procedure was conducted as for Group 3, plus an intermediate layer of PLF was applied as for Group 2. In Group 5 (CSEB), the control group, CSEB was applied according to the manufacturer's directions; in Group 6 (CSEB/PLF), an intermediate layer of PLF was applied; in Group 7 (SH/CSEB), the cavity surface was pre-treated with SH; in Group 8 (SH/CSEB/PLF), SH pre-treatment was conducted as for Group 7, then an intermediate layer of PLF was applied; in Group 9 (CSEB/SH), after CSEB-primer application, the surface was treated with SH, followed by CSEB-adhesive application and in Group 10 (CSEB/SH/PLF), the same was conducted as for Group 9, then an intermediate layer of PLF was applied. The specimens were stored at 37°C for 24 hours, polished, molded and replicas were obtained in epoxy resin. The replicas were gold-sputter coated and observed by SEM (300x) for marginal quality classification. The Kruskal-Wallis non-parametrical multi-comparison Test (p<0.05) was used to obtain statistical analysis of the data. Results demonstrated that both adhesive systems in the control groups presented low marginal quality and a high variability. The use of an intermediate layer of PLF significantly improved the marginal quality with the CSEB system but had no effect with the PB system. Collagen depletion with SH enhanced marginal quality for the PB system and did not influence the CSEB system results. [ABSTRACT FROM AUTHOR]