No abstract

The preparation of retention slots may increase the fracture resistance of endodontically-treated teeth, especially, when restored with short fibre-reinforced composite. The use of short fibre-reinforced composite with retentive slots could be an alternative technique to prevent cuspal fracture on endodontically-treated teeth with MOD cavity.

This study investigated the radiopacity values of glass ionomer-and resin-based bulk-fill restoratives of different thicknesses using digital radiography. Two glass ionomer-based and three resin-based bulk-fill restoratives, and a conventional composite were studied. Five disc-shaped specimens were prepared from each of these materials at three different thicknesses; specimens of enamel and dentin with the same thicknesses were also prepared. Materials were placed over a complementary metal oxide-semiconductor sensor together with the tooth specimen and an aluminum step-wedge, and then exposed using a dental X-ray unit. The images were analyzed using a software program to measure the mean gray values (MGVs), which were converted to equivalent aluminum thicknesses. Two-way ANOVA was used to investigate the significance of differences among the groups. The GCP Glass Fill specimens showed the lowest radiopacity values, and the Quixfil specimens had the highest values. All materials had higher radiopacity values than enamel and dentin, except for GCP Glass Fill, which had a radiopacity similar to that of enamel. The resin-based bulk-fill restoratives had significantly higher radiopacity values than glass ionomer-based restoratives. All of the tested materials showed radiopacity values higher than that of dentin, as recommended by the ISO. (J Oral Sci 57, 79-85, 2015)

The aim of this study was to evaluate the intrapulpal temperature changes during the curing of different bulk-fill restorative materials. Ten mandibular molar teeth were selected and occlusal surfaces were removed to obtain a standard 0.5 mm occlusal dentin thickness. Five bulk-fill restorative materials and a conventional resin composite (control) were applied. The intrapulpal temperature changes during the curing of these materials were determined by a device simulating pulpal blood microcirculation. The difference between the initial and maximum temperature values (Δt), was recorded. The data were statistically analyzed with one-way ANOVA and Tukey's HSD test (p<0.05). There were statistically significant differences between materials (p<0.001). The light-curing bulkfill restoratives exhibited the highest Δt values. Equia Forte showed the lowest Δt values among all the groups (p<0.05). Bulk-fill restorative materials causes significantly different temperature changes in the pulp chamber according to curing type. Therefore, clinicians should be considered when using these materials.

This study investigated the radiopacity values of bulk-fill restoratives by using two digital radiography systems. Nine bulk-fill restoratives and a conventional composite were used in the study. Six disc-shaped specimens were prepared from each of these materials, three each at thicknesses of 1 mm and 2 mm, and tooth slices with these same thicknesses were obtained. As a control, an aluminum step wedge varying in thickness from 0.5 to 10 mm in was used. Three specimens of each of the materials, together with the tooth slice and the aluminum step wedge, were placed over a complementary metal oxide semiconductor (CMOS) sensor and a storage photostimulable phosphor (PPS) plate system and exposed using a dental x-ray unit. The images were analyzed using a software program to measure the mean gray values (MGVs). Five measurements were obtained from each of the restorative materials, the enamel, the dentin, and the stepwedge. The MGVs were converted to the equivalent aluminum thicknesses. Three-way analysis of variance (ANOVA) was used to determine the significance of the differences among the groups. A Tukey test was applied for pairwise comparisons (p<0.05). All composite-based restoratives were found to have greater radiopacities than enamel or dentin. Equia Fil had the lowest radiopacity value. Radiopacity increased as the thicknesses of the restorative material increased. The CMOS system showed significantly higher radiopacity values than the PSP system. In conclusion, all investigated bulk-fill restoratives passed the International Organization for Standardization and American National Standard Institute/American Dental Association requirements for radiopacity values when evaluated with the two digital radiography systems.