Root Canal Filling: Fracture Strength of Fiber-Reinforced Composite-Restored Roots and Finite Element Analysis

Abstract

The aims of this study were to evaluate the effect of root canal filling techniques on root fracture resistance and to analyze, by finite element analysis (FEA), the expansion of the endodontic sealer in two different root canal techniques. Thirty single-rooted human teeth were instrumented with rotary files to a standardized working length of 14 mm. The specimens were embedded in acrylic resin using plastic cylinders as molds, and allocated into 3 groups (n=10): G(lateral) - lateral condensation; G(single-cone) - single cone; G(tagger) - Tagger's hybrid technique. The root canals were prepared to a length of 11 mm with the #3 preparation bur of a tapered glass fiber-reinforced composite post system. All roots received glass fiber posts, which were adhesively cemented and a composite resin core was built. All groups were subjected to a fracture strength test (1 mm/min, 45°). Data were analyzed statistically by one-way ANOVA with a significance level of 5%. FEA was performed using two models: one simulated lateral condensation and Tagger's hybrid technique, and the other one simulated the single-cone technique. The second model was designed with an amount of gutta-percha two times smaller and a sealer layer two times thicker than the first model. The results were analyzed using von Mises stress criteria. One-way ANOVA indicated that the root canal filling technique affected the fracture strength (p=0.004). The G(lateral) and G(tagger) produced similar fracture strength values, while G(single-cone) showed the lowest values. The FEA showed that the single-cone model generated higher stress in the root canal walls. Sealer thickness seems to influence the fracture strength of restored endodontically treated teeth.

Stress Generated by Customized Glass Fiber Posts and Other Types by Photoelastic Analysis

“…Unfortunately, carbon fiber posts do not allow a good aesthetic restoration with all-ceramic crowns. To compensate for this, glass and quartz fiber posts were introduced (1,11) which claimed the same advantages as carbon fiber posts, but with better esthetics (10,12,13). However, the use of prefabricated composite posts may become critical if restoration of a wide flared root cavity is entailed because a lot of cement has to be used to fix it (14).…”

Fracture Resistance of Simulated Immature Teeth after Different Intra-radicular Treatments

“…The use of the intra-radicular posts in immature teeth has been suggested to increase root fracture resistance, allowing for a more favorable prognosis (1). The cementation may be performed with composite resin and self-adhesive resin cements, glass ionomer cement or even mineral trioxide aggregate (MTA) (2)(3)(4). MTA may be indicated as an apical plug in the treatment of immature teeth (5), resulting in a faster treatment and inducing the formation of mineralized tissue in the root apex (6).…”

Effect of three different veneering techniques on the stress distribution and in vitro fatigue behavior of core-veneer all-ceramic fixed partial dentures

“…For that, five rectangular specimens (20×10×4 mm) of each ceramic were prepared according to the manufacturer’s instructions and polished sequentially with P600-, P800-, and P1200-grit SiC abrasive to a consistent surface finish. 22 During the test, the supported rectangular specimen was excited manually using a light impact hammer, and the acoustic response was recorded to determine the natural vibration frequencies (ATCP Sonelastic, Physical Engineering, Ribeirão Preto, SP, Brazil). Measurements were repeated 10 times for each sample, and the mean elastic modulus and Poisson ratio were calculated.…”

“…Measurements were repeated 10 times for each sample, and the mean elastic modulus and Poisson ratio were calculated. 22 Following material property assignments and mesh sensitivity analysis, all contacts were considered ideally bonded, and the fixation occurred in the base of the substrate. 23 A 100-N load was applied on the pontic in contact with the grinding slope of the mesio-vestibular cusp of the pontic.…”