Fracture resistance of endodontically treated premolars with fibre-reinforced composite restorations.

This study investigated the fracture resistance and failure mode of endodontically treated premolars restored with a glass fibre-reinforced composite resin. Endodontically treated maxillary premolars were divided in 4 groups: group O: occlusal access opening restored with direct composite; group O+: as group O but with fibre reinforcement; group MOD: occlusal access opening and mesio-distal (MOD) cavity restored with direct composite; group MOD+: as group MOD but with additional fibre reinforcement. Pairwise comparisons of the fracture force among all groups was performed (95% confidence level). Fractures were classified in 4 groups depending on the type of fracture. Group O was the strongest (452.7N) and group MOD the weakest (292.4N). Fracture resistance was significantly different among all groups, except between groups O+ and MOD+. The majority of the unreinforced teeth displayed unfavourable fractures, while the reinforced teeth displayed more favourable fractures. The incorporation of glass fibre weakened endodontically treated but otherwise intact premolars; premolars with MOD restorations were stronger if reinforced with fibres. Fibre reinforcement led to more favourable fractures.

Coronal leakage of teeth root-filled with gutta-percha or Resilon root canal filling material.

This study compared the micro-leakage of a root canal filled with Resilon or gutta-percha (GP), utilizing either cold lateral condensation or System B. Four experimental groups were used. Group one was obturated with GP using cold lateral condensation, group two with GP using System B, group three with Resilon using cold lateral condensation, and group four with Resilon using System B. Micro-leakage was tested using a two-chamber bacterial method as well as a dye penetration test. Data was subjected to statistical analysis using an ANOVA. A p-value <0.05 was considered as significant. The bacterial micro-leakage test showed no significant difference between GP and Resilon when using Cold Lateral condensation (p = 0.2695) or System B (p = 0.5602). The dye penetration test also showed no significant difference between GP and Resilon using either the Cold Lateral condensation (p = 0.2713) or the System B techniques (p = 0.0767). The ability of GP and Resilon to seal a root canal is similar.