In vitro evaluation of fracture strength of dental weakened roots rehabilitated with cores associated with fiberglass posts

Author(s)

Érika Manuela Asteria Clavijo

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2013-02-28

Examining board members

Caio Cezar Randi Ferraz; José Flávio Affonso de Almeida; José Maurício dos Santos Nunes Reis

• Advisor: Caio Cezar Randi Ferraz

Abstract

The aim of this is study was to evaluate in vitro fracture strength of weakened roots with 3 thicknesses of dentin, in which were cemented fiberglass posts and anatomic fiber posts (fiberglass post with composite resin). 180 freshly extracted bovine incisors were used. The crowns and apices of were sectioned to create the samples with 14 mm of root. The samples were divided into 3 groups: Group 1 (G1) = dentin walls with 1 mm thickness (n = 60), Group 2 (G2): dentin walls with 2 mm thickness (n = 60) and Control Group (G3) = roots without weakening (n = 60). 4mm apical root canal was sealed with Coltosol ®, and the samples were inserted into artificial periodontal ligament with an impression material and acrylic resin. Then, each group was divided into two subgroups (n = 30) that received roots luting of glass fiber post only (P) and roots receiving cementing anatomic fiber post (PR). The cement Relyx ARC ® was used for cementation of intracanal retainers. The samples were tested for fracture strength in a universal testing machine with load application angle of 135 degrees with the long axis of the specimen by palate (n = 90) and vestibular (n = 90). The values were recorded in Newtons (N) and statistically analyzed by ANOVA. The fractures were evaluated in clinical microscope and classified after fracture as favorable and unfavorable. Results from this study showed no statistically significant difference among the groups (p > 0.05) to the fracture strength test with forces applied by vestibular. On the lingual face there was statistically significant difference between groups G1PR and G1P when compared to CPR (p< 0.05). On the vestibular face the specimens restored with anatomic post that had root fracture from groups G1, G2 and G3 had the incidence of favorable fractures in 87.5%, 80% and 83.3% of the cases. By lingual the CPR group had fractures only in filling cores, with no root fractures. The G1PR and G1P showed 80% of specimens with root fractures, of which 91.67% and 66.67% were classified as favorable. The different thicknesses of dentin did not affect the fracture strength, suggesting that teeth with weakened walls are easily restorable. By Lingual. The anatomic post showed higher resistance to fracture. Most root fractures, when occur in teeth restored with fiberglass posts are considered favorable (AU)

• FAPESP's process: 11/15781-2 - In vitro resistance to fracture of weakened roots simulated immature teeth rehabilitated by two techniques to manufacture intraradicular.
• Grantee: Erika Manuela Asteria Clavijo
• Support Opportunities: Scholarships in Brazil - Master