title: Fracture resistance of weakened roots restored with composite resin and glass fiber post.
abstract: This study evaluated the fracture resistance of weakened roots restored with glass fiber posts, composite resin cores and complete metal crowns. Thirty maxillary canines were randomly divided into 3 groups of 10 teeth each: teeth without weakened roots (control); teeth with partially weakened roots (PWR) and teeth with and largely weakened roots (LWR). The control group was restored with glass fiber posts and a composite resin core. Teeth in the PWR and LWR groups were flared internally to standardized dimensions in order to simulate root weakness. Thereafter, the roots were partially filled with composite resin and restored in the same way as in the control group. The specimens were exposed to 250,000 cycles in a controlled chewing simulator. All intact specimens were subjected to a static load (N) in a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed by one-way ANOVA and Dunnett's test for multiple comparisons (p=0.05). There were statistically significant difference differences (p<0.01) among the groups (control group = 566.73 N; PWR = 409.64 N; and LWR = 410.91 N), with significantly higher fracture strength for the control group. There was no statistically significant difference (p>0.05) between the weakened groups. The results of this study showed that thicker root dentin walls significantly increase the fracture resistance of endodontically treated teeth.
authors.affiliation: Department of Prosthodontics, Dental School of São José dos Campos, State University of São Paulo, São Jose dos Campos, SP, Brazil.
authors.forename: Lucas Villaça
authors.initials: LV
authors.lastname: Zogheib
authors.forename: Jefferson Ricardo
authors.initials: JR
authors.lastname: Pereira
authors.forename: Accácio Lins
authors.initials: AL
authors.lastname: do Valle
authors.forename: Jonas Alves
authors.initials: JA
authors.lastname: de Oliveira
authors.forename: Luiz Fernando
authors.initials: LF
authors.lastname: Pegoraro
mesh_terms: D003188:Composite Resins; D003442:Crowns; D003481:Cuspid; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003804:Dentin / Q000502:physiology; D017220:Dentin-Bonding Agents; D005898:Glass; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D011176:Post and Core Technique; D019279:Resin Cements; D014082:Tooth Fractures / Q000517:prevention & control*
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C425844:Scotchbond Multi-Purpose Plus; C009753:fiberglass