The purpose of this study is to evaluate the effect of a bioactive glass-based root canal sealer, Nishika Canal Sealer BG (CS-BG), on the incidence of postoperative pain (PP) after root canal obturation (RCO). Eleven dentists performed pulpectomy or infected root canal treatments for 555 teeth. During RCO, CS-BG was used. After RCO, the rate of PP and the factors affecting PP (pain during RCO and pain immediately after RCO) were analyzed. PP was observed in eight teeth (1.5%), and within 7 days after RCO, there were no teeth with pain. In these teeth with PP, there was a significant difference in the occurrence of pain during RCO, but not in the occurrence of pain immediately after RCO, when compared with pulpectomy and infected root canal treatment. These clinical results show that CS-BG has an excellent biocompatibility, and can suppress the distress of patients during RCO.

This is the second paper of a series that describes the curing process of styrene-butadiene-rubber packed in a cylindrical mold with inner diameter of 74.6 mm. Present paper mainly describes the curing process under the mold cooling stage. Sulfur was used as the curing agent and the sulfur concentration ranged from 1.0 to 5.0 weight percent. The mold temperature was controlled in two stages. The mold was heated at 414 K for 45 min. then switched off, and the mold was cooled by natural convection to the surroundings up to 75 min. Time-dependent radial distributions of the temperature profile and the crosslink density were measured in the cooling stage. It was confirmed that the curing reaction was related strongly to the temperature field. In the cooling stage, rubber temperature decreased in the outer zone whereas overshooted in the inner zone. The degree of cure at the rubber center reached to around 0.8 at time 45-60 min. elapsed after taking the heater off for sulfur concentration of 1 and 3 weight percent.

This study aimed to examine the resin polymerization of a fiber post/core resin construction system and the interface between resin and root canal sealers, which are important for root canal sealing. We used the i‑TFC Luminus fiber post and i‑TFC Luminus LC flow (i‑TFC‑L), the GC fiber post and Unifil Core EM (GCF), and the FiberKor post and Build‑It FR (FKP) as core construction systems, and Nishika Canal Sealer BG (CS‑BG), Metaseal Soft (META), and Nishika Canal Sealer EN (CS‑EN) as sealers. The light transmission of fiber posts (n = 5), the polymerization of core resin (n = 5), and the adhesion between the sealer and core resin (n = 10) were evaluated. The i‑TFC Luminus fiber post light transmission was significantly higher than that of other posts. Without shielding, i‑TFC‑L showed a significantly greater amount of polymerized resin than the other systems. With shielding, although i‑TFC‑L showed a significantly greater amount of polymerized resin immediately after light irradiation, polymerized resin was significantly greater in GCF and FKP after 10 min. All systems adhered to CS‑BG and META but not to CS‑EN. These results indicate that resin polymerization in the cavity differs among fiber post/core resin construction systems and that the adhesion of the resin and sealer depends on the property of the sealer.