Tensile bond strength of indirect composites luted with three new self-adhesive resin cements to dentin

OBJECTIVE: The aims of this study were to evaluate the tensile bond strengths between indirect composites and dentin of 3 recently developed self-adhesive resin cements and to determine mode of failure by SEM. MATERIAL AND METHODS: Exposed dentin surfaces of 70 mandibular third molars were used. Teeth were randomly divided into 7 groups: Group 1 (control group): direct composite resin restoration (Alert) with etch-and-rinse adhesive system (Bond 1 primer/adhesive), Group 2: indirect composite restoration (Estenia) luted with a resin cement (Cement-It) combined with the same etch-and-rinse adhesive, Group 3: direct composite resin restoration with self-etch adhesive system (Nano-Bond), Group 4: indirect composite restoration luted with the resin cement combined with the same self-etch adhesive, Groups 5-7: indirect composite restoration luted with self-adhesive resin cements (RelyX Unicem, Maxcem, and Embrace WetBond, respectively) onto the non-pretreated dentin surfaces. Tensile bond strengths of groups were tested with a universal testing machine at a constant speed of 1 mm/min using a 50 kgf load cell. Results were statistically analyzed by the Student's t-test. The failure modes of all groups were also evaluated. RESULTS: The indirect composite restorations luted with the self-adhesive resin cements (groups 5-7) showed better results compared to the other groups (

A new silicon-based root canal sealer (Roekoseal((R))-Automix)

This study evaluated the new silicon-based sealer 'Roekoseal((R)) -Automix' (RSA) with respect to sealing, bonding capabilities and biocompatibility with rat subcutaneous connective tissue. For the microleakage study, 36 single rooted teeth were instrumented and 30 of these obturated with either Grossman's sealer or RSA using lateral condensation technique (15 of each). Six teeth were not obturated and used as control group. For investigating bonding capability, 10 of the obturated roots with RSA and Grossman's sealer were ground and split longitudinally and examined by scanning electron microscopy (SEM). The RSA was found to seal significantly better than Grossman's sealer. The SEM examination revealed a good bond between RSA and the dentine and between RSA and the gutta-percha. Tissue reaction was evaluated by injecting 0.1 mL RSA into the connective tissue of 21 male Albino-Wistar rats and observing at 24 h, 7 days and 30 days and 30 days. Formation of a new granulation tissue with fibrous tissue adjacent to the material at 30 days. This study found that RSA performed well

Shear Bond Strength of Indirect Composites Luted with Three New Self-Adhesive Resin Cements to Dentin

The aim of this study was to evaluate the shear bond strengths of indirect composites (those cured outside the mouth) luted by three different, recently developed, self-adhesive resin cements to dentin. Seventy caries-free mandibular third molar teeth embedded in acrylic resin and with exposed dentin surfaces were used. Teeth were randomly divided into seven groups. The following application protocols were carried out: a) Group 1 (control group)direct composite resin restoration (Alert) with total-etch adhesive system (Bond 1 primer/adhesive); b) Group 2indirect composite restoration (Estenia) luted by a resin cement (Cement-It) combined with the same total-etch adhesive; c) Group 3direct composite resin restoration with self-etch adhesive system (Nano-Bond); d) Group 4indirect composite restoration luted by the resin cement combined with the same self-etch adhesive; e) Groups 5-7indirect composite restoration luted with self-adhesive resin cements (RelyX Unicem (R), Maxcem (R), and Embrace WetBond (R), respectively) onto untreated dentin surfaces. Shear bond strengths of the groups were performed with a universal testing device. Results were statistically analysed by student-t and one way ANOVA tests. The fractured surfaces were also examined by SEM. The indirect composite restorations luted with the self-adhesive resin cements (Groups 5-7) showed successful results compared with the other groups (p0.05). Group 4 showed the weakest bond strength (p0.05). Open dentin tubules were observed on the total-etch adhesive applied surfaces whereas a smear rich layer was found by SEM on the self-etch adhesive applied surfaces. The new universal self-adhesive resins may be considered an alternative for luting the indirect composite restorations onto the untreated dentin surfaces

Effects of the Nd : YAG laser, air-abrasion, and acid-etchant on filling materials

The purpose of this study was to determine any inadvertent effects of the neodymium: yttrium-aluminium-garnet (Nd:YAG) laser, air-abrasion, and ortho-phosphoric acid on some conventionally used dental filling materials [amalgam, composite resin, compomer, glass-ionomer cement (GIC), and ceromer], when they were used for purposes of margin etching and assessed according to standard enamel etching parameters using a total of five fillings. The surfaces of the filling materials were polished. One sample from each material group was exposed to laser (at 0.75 J, 15 pps) and air abrasion (with Al-oxide powder, 60 psi) for 2 s and to the 37% ortho-phosphoric acid for 60 s. The exposed materials were examined under Scanning Electron Microscopy (SEM). After laser treatment most specimens showed recrystallized areas, the GIC surface being the most affected. There were some pores and cavities on the amalgam surface following laser treatment. The abraded surfaces showed mechanical abrasions. The acid etchant showed the least effect. During the application of laser or air-abrasion, the adjacent tooth or filling surface must be protected or the dentist must be careful

Longevity of direct diastema closure and recontouring restorations with resin composites in maxillary anterior teeth: A 4-year clinical evaluation

Objectives To evaluate the clinical performance of resin composite restorations and to investigate causes of failure. Materials and Methods The longevity of 216 restorations in 53 patients (mean age, 33.3 years) was retrospectively evaluated according to Federation Dentaire Internationale (FDI) criteria. Dental history and photographic data were used to evaluate diastema closure (n = 199) and recontouring (n = 19) restorations comprising microhybrid (Essentia Universal, GC Corp.), nanohybrid (Ceram.x One, Dentsply Sirona), and nanofilled (Estelite Asteria, Tokuyama Dental) composites. Data were analyzed with the Kaplan-Meier log-rank test, Cox regression analysis, Pearson chi-square test. p < 0.05 was considered statistically significant. The overall survival rate was 90.3 % and the mean survival duration was 46.2 months during the for 4 - year study period. The annual failure rate was 0.9 % - 3.4 %. Mean survival durations for diastema closure and recontouring restorations were 46.2 and 45.9 months, respectively (p = 0.328). Mean survival durations for Essentia Universal, Estelite Asteria, and Ceram.x One were 46.1, 46.7, and 45.7 months, respectively (p = 0.677). If we include failed restorations that were repaired and remained functional, the overall survival rate was 100 %. Conclusion Longevity was similar among composites and restoration types. The long-term clinical performance of monochromatic anterior composite restorations was robust. Composite repair may be suitable for diastema closure and recontouring restorations. Clinical Significance There is a lack of long-term clinical evidence regarding the performance of direct anterior composite restorations. Monochromatic direct composite restorations may meet both the esthetic and functional expectations with even simpler restorative techniques. This 4 - year follow-up study evaluated the clinical performance of monochromatic anterior diastema closure and recontouring restorations with three different composite materials. The longevity of the restorations and the reasons for failure were investigated