Root canal filling: fracture strength of fiber-reinforced composite-restored roots and finite element analysis.
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.
Department of Dental Materials and Prosthodontics, São José dos Campos School of Dentistry, UNESP - Univ Estadual Paulista, São José dos CamposSP, Brazil.
Marília Pivetta
MP
Rippe
Department of Stomatology, School of Dentistry, UFSM - Federal University of Santa Maria, Santa MariaRS, Brazil.
Manuela Favarin
MF
Santini
Department of Stomatology, School of Dentistry, UFSM - Federal University of Santa Maria, Santa MariaRS, Brazil.
Carlos Alexandre Souza
CA
Bier
Department of Dental Materials and Prosthodontics, São José dos Campos School of Dentistry, UNESP - Univ Estadual Paulista, São José dos CamposSP, Brazil.
Alexandre Luiz Souto
AL
Borges
Department of Restorative Dentistry, School of Dentistry, FUFSM - Federal University of Santa Maria, Santa MariaRS, Brazil.
Luiz Felipe
LF
Valandro
D003188:Composite Resins / Q000627:therapeutic use*; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D005898:Glass; D006171:Gutta-Percha; D006801:Humans; D066298:In Vitro Techniques; D012387:Root Canal Filling Materials / Q000627:therapeutic use*; D012389:Root Canal Obturation / Q000379:methods*; D018915:Root Canal Preparation / Q000379:methods*; D014082:Tooth Fractures / Q000503:physiopathology*; D014092:Tooth Root
D003188:Composite Resins; D012387:Root Canal Filling Materials; C009753:fiberglass; D006171:Gutta-Percha