The aim of this study was to investigate the frequency of flowable resin composite restorations compared with conventional paste resin composite restorations. Ten dentists restored various kinds of lesions with resin bonding and flowable and/or paste resin composite for three months. The lesions were classified into Class I, II, III, IV, V, WSD, Root surface cavity, Incisal defect, Facing, Repair of facing crown, and Others. The widths of lesions were divided into three grades: narrow (<1 mm), medium (1-2 mm), and wide (≥2 mm), and the depths were divided into three grades: shallow (<1 mm), medium (1-2 mm), and deep (≥2 mm). The resin composite restorations were classified into three patterns: F (flowable resin composite restoration), P (paste resin composite restoration), and F+P (combination restoration with both flowable and paste resin composite). As a result, the total number of resin composite restorations was 1,122, categorized into flowable resin composite restoration 567 (50.5%), paste resin composite restoration 378 (33.7%), and combination restoration 177 (15.8%). Flowable resin composite restorations accounted for over half the number in cases of Class III, Class V, WSD, Root caries, and Repair. Furthermore, flowable resin composite restorations accounted for over half in the narrow or shallow groups, while combination restorations accounted for over half in the wide and deep groups.

View full abstract

The clinical value of injectable resin composites in dental practice has increased. A recently developed fluoridereleasing injectable resin “Beautifil Flow Plus” (SHOFU), which uses S-PRG technology, has been placed on the market. This injectable resin, which is not only for anterior cavities but also for posterior cavities, offers high mechanical properties, proper flow and clinical usability. The aim of this study was to observe the polished surface of Beautifil Flow Plus resin by using FE-SEM, to measure the flexural strength and compressive strength, and to evaluate the clinical performance using extracted human molars in vitro and in vivo. As a result, we observed that spherical filler particles of 0.8 μm in diameter and S-PRG nanofiller particles were densely filled between the glass fillers in the polished specimens. The flexural strength of Beautifil Flow Plus F00 and F03 was about 130 MPa, which was significantly higher than that of Beautifil Flow F02 and F10, but the same as that of Beautifil II. The compressive strength of Beautifil Flow Plus F00 and F03 was about 350 MPa, which was significantly higher than that of Beautifil II, but the same as that of Beautifil Flow F02 and F10. The evaluation of the clinical performance of Beautifil Flow Plus in vitro/in vivo showed that it is easy to build up and create anatomical forms according to the proper flow and hardness. We conclude that “Beautifil Flow Plus”injectable resin could be effectively used for both anterior and posterior cavities.

View full abstract

The objective of this study was to evaluate the dentin bond strength and sealing ability of adhesive materials used for the treatment of dentin desensitizers. The superficial occlusal dentin of 32 extracted human molars was used. Sealing coat material: Hybrid coat (HC, Sun Medical), adhesive dentin desensitizers: Shield force (SF, Tokuyama Dental) and ClinproTMXT Varnish (XT, 3M ESPE) and one-step dentin adhesive: Bond force (BF, Tokuyama) were applied to 320-grit abraded dentin surfaces. First, the microtensile bond strength of each specimen was measured in a universal testing machine. Next, dentinal tubules occlusion in each specimen was measured using a fluid filtration system. The microtensile bond strength in all materials was 30 MPa or over and there was no significant difference among HC, SF, XT and BF. Moreover, there was no significant difference in fluid movement among all materials. These results indicated that the sealing coat material, dentin desensitizers and a one-step dentin adhesive used in this study provided excellent bond strength and sealing ability in the dentin hypersensitivity model.

View full abstract

The purpose of this study was to evaluate the influence of storage conditions on the adhesive performance of an experimental adhesive system (LLB-2). Adhesives were applied according to the manufacturer’s instructions and experimental flowable resin composite was inserted into the mold on the enamel and dentin surfaces of bovine teeth, and then irradiated with light. These specimens were stored in 37°C distilled water for 10 min, 24 h, or were subjected to thermal cycling. Shear bond strength was measured and the fracture mode after testing was observed with scanning electron microscopy (SEM). Enamel bond strength after 10 min and 24 h storage in water ranged from 17.9 to 20.1 MPa, and dentin bond strength ranged from 14.8 to 16.4 MPa. After thermal cycling, enamel and dentin bond strengths decreased compared to those obtained in the initial storage period. From the SEM observations of fractured resin surfaces, mixed failure was frequently observed for the 10 min and 24 h specimens. After thermal cycling, the dominant failure mode was adhesive and/or mixed fracture. The results of this study indicate that the experimental adhesive system has a stable bonding ability to both enamel and dentin.

View full abstract