Effect of the C-factor and dentin preparation method in the bond strength of a mild self-etch adhesive.

This study evaluated the effect of the C-factor and dentin preparation method (DPM) in the bond strength (BS) of a mild self-etch adhesive; the study also observed the SEM superficial aspects of the corresponding smear layer. For purposes of this study, 25 molars (n=5) were used in a bond strength test. The molars were divided into two parts (buccal and lingual): one part received a Class V cavity (C-factor=3) and the other received a flat surface (C-factor=0) with the same bur type (coarse diamond or carbide bur and fine diamond or carbide bur), both within the same dentin depth. Five teeth were prepared with wet 60-grit and 600-grit SiC papers. After restoration with Clearfil SE Bond, microtensile beans (0.8 mm2) were prepared and tested after 24 hours in a universal testing machine (0.5 mm/minute). An additional two teeth for each DPM were prepared for SEM evaluation of the smear layer superficial aspects. The BS values were submitted to one-way ANOVA, considering only the DPM (flat surfaces) and two-way ANOVA (C-Factor x DPM, considering only burs) with p=0.05. Although the DPM in the flat surfaces was not significant, the standard deviations of carbide bur-prepared specimens were markedly lower. The BS was significantly lower in cavities. The fine carbide bur presented the most favorable smear layer aspect. It was concluded that different dentin preparation methods could not prevent the adverse effect in bond strength of a high C-factor. A coarse cut carbide bur should be avoided prior to a mild self-etch adhesive, because it adversely affected bond strength. In contrast, a fine cut carbide bur provided the best combination: high bond strength with low variability, which suggests a more reliable bond strength performance.

Fluorescence of primary dentine after chemomechanical and conventional rotary excavation.

AIM: This was to compare fluorescence values of dentine remaining after caries removal using chemomechanical systems and conventional rotary methods. STUDY DESIGN: In vitro study. METHODS: 30 extracted primary teeth with proximal carious cavities were divided into three groups according to caries removal method: Carisolv, Papacarie and conventional low speed rotary burs. Carious (initial) and remaining (final) dentine evaluations were assessed by visual-tactile examination and DIAGNOdent. Transversal microhardness (TMH) of remaining dentine was evaluated. Fluorescence and TMH values were submitted to two-way ANOVA and the post hoc Tukey test (alpha = 0.05) and Pearson's linear correlation. RESULTS: Two-way ANOVA revealed that fluorescence values were similar between conventional rotary excavation, Carisolv and Papacarie groups (p = 0.0542). No statistically significant differences (p = 0.1147) were found to TMH values. No correlation was found between fluorescence and TMH values (r = -0.0273). CONCLUSION: All caries excavation methods resulted in similar remaining dentine fluorescence values. No correlation was found between fluorescence values and TMH of remaining dentine.

One-year clinical evaluation of posterior packable resin composite restorations.

This study evaluated the clinical performance of four packable resin composite restorative materials in posterior teeth (Class I and II) compared with one hybrid composite after one year. Eighty-four restorations were placed in 16 patients. Each patient received at least five restorations. The tested materials were: (1) Solitaire + Solid Bond; (2) ALERT + Bond-1; (3) Surefil + Prime & Bond NT (4) Filtek P60 + Single Bond and; (5) TPH Spectrum + Prime & Bond 2.1. All restorations were made using rubber dam isolation, and the cavity design was restricted to the elimination of carious tissue. Deeper cavities were covered with calcium hydroxide and/or glass ionomer cement. In shallow and medium cavities, no protection was performed except for the respective adhesive system used in each group. Each adhesive system and resin composite was placed according to the manufacturer's instructions. One week later, the restorations were finished/polished and evaluated according to the USPHS modified criteria. All patients attended the one-year recall, and the 84 restorations were evaluated at that time based on the same evaluation criteria. The scores were submitted to statistical analysis (Chi-square test, p<0.05). Solitaire and TPH showed some fractures at marginal ridges. Solitaire, ALERT and TPH showed some concerns related to color match and surface texture. Surefil and Filtek P60 showed an excellent clinical performance after one year.

Clinical evaluation of an adhesive used as a fissure sealant.

PURPOSE: To compare the retention of a multi-use bonding agent (OptiBond) to a conventional sealant (Delton) used as pit and fissure sealants. MATERIALS AND METHODS: An informed consent was obtained from 38 subjects aged 11-17 yrs. Delton, a self-cured sealant, was applied to 86 teeth, and OptiBond, a dual-cure glass filled adhesive, was applied to 85 teeth, under cotton roll isolation and saliva ejector. Each subject received both sealing materials, randomly assigned to the sides of the mouth. The sealed teeth were followed up to 30 months. Clinical evaluation was performed by two examiners and the retention was classified as failure or success. RESULTS: Statistical analysis based on a stratified Cox proportional hazards regression model indicated that OptiBond had better clinical performance than Delton (P < 0.001).