silicon and Dental-Leakage

Because leakage along root fillings may increase or decrease during the long period after filling, the accumulated leakage data measured repeatedly after filling are clinically more relevant than the data measured just once shortly after filling. The aim of this study was to determine the long-term sealing ability of a recently developed root canal sealer RSA RoekoSeal (Roeko Dental Products, Langenau, Germany).. Eighty extracted human mandibular premolars were equally divided into 4 groups (n = 20) and root canal instrumented. Canals in group 1 were obturated with laterally compacted gutta-percha points and RSA, in groups 2 to 4 with vertically compacted warm gutta-percha using RSA in group 2, Pulp Canal Sealer (Kerr, Romulus, Mich) in group 3, and no sealer in group 4. With the use of a fluid transport model, leakage along entire root fillings was measured before post space preparation. After post space preparation, leakage along the remaining apical root fillings was measured repeatedly at 1 week, 1, 2, 6, 12, and 18 months respectively and recorded in microliters per day.. Before post space preparation, groups 1 and 2 leaked significantly less than groups 3 and 4 (P = .001), whereas no significant difference existed between the groups 1 and 2 (P = .317) or between the groups 3 and 4 (P = .074). For each group, a summation of the leakage at all time intervals after the post space preparation showed that the 2 RSA groups leaked significantly less than the other 2 groups (P =.000). However, no significant difference existed between the 2 RSA groups (P = .993) and between the groups 3 and 4 (P = .149).. RSA used in combination with either cold laterally compacted or warm vertically compacted gutta-percha provided a consistent seal during a period of 18 months.

Topics: Bicuspid; Dental Bonding; Dental Cements; Dental Leakage; Follow-Up Studies; Gutta-Percha; Hot Temperature; Humans; Humidity; Longitudinal Studies; Materials Testing; Post and Core Technique; Root Canal Filling Materials; Root Canal Preparation; Silicon; Statistics, Nonparametric; Temperature; Tooth Apex; Zinc Oxide-Eugenol Cement

This study evaluated the new silicon-based sealer 'Roekoseal-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.

Topics: Animals; Dental Bonding; Dental Cements; Dental Leakage; Dentin-Bonding Agents; Materials Testing; Rats; Rats, Wistar; Root Canal Filling Materials; Silicon

High 24-hour tensile and shear bond strengths have been reported for silane-primed resin/porcelain interfaces, but bonds often failed after prolonged water storage. This study was designed to determine the influences of both a silane primer and thermocycling on interfacial leakage between a light-cured BisGMA resin and dental porcelain. Porcelain discs measuring 10 mm in diameter and 1.5 mm in thickness were fired. Axial cylindrical cavities were prepared through the discs with a diamond bur. Four groups of eight discs each were restored in the following modes: groups 1 and 2 with light-cured bonding agent and light-cured microfilled resin, and groups 3 and 4 with a silane primer followed by the same bonding agent and resin. Specimens were water-stored for 24 hr, after which those in groups 2 and 4 were thermocycled 200 times between 4 degrees C and 60 degrees C. Specimens were then sealed to steel anodes and placed in 1% KCl, maintained at 21 degrees C, around a stainless steel cathode. Leakage currents were recorded daily for 30 days and after six months, by application of a 10 V potential difference between the cathode and each anode. Positive and negative controls gave massive and nil readings, respectively. The mean leakages were consistently greatest in group 2 (being significantly greater than for the other groups). Results suggest that silane priming minimizes leakage at the resin/porcelain interface after thermal cycling.

Topics: Bisphenol A-Glycidyl Methacrylate; Composite Resins; Dental Bonding; Dental Leakage; Dental Porcelain; Dental Stress Analysis; Electrodes; Polymethacrylic Acids; Silanes; Silicon