title: Influence of different cantilever extensions and glass or polyaramide reinforcement fibers on fracture strength of implant-supported temporary.
abstract: In long-term oral rehabilitation treatments, resistance of provisional crowns is a very important factor, especially in cases of an extensive edentulous distal space. The aim of this laboratorial study was to evaluate an acrylic resin cantilever-type prosthesis regarding the flexural strength of its in-balance portion as a function of its extension variation and reinforcement by two types of fibers (glass and polyaramid), considering that literature is not conclusive on this subject. Each specimen was composed by 3 total crowns at its mesial portion, each one attached to an implant component (abutment), while the distal portion (cantilever) had two crowns. Each specimen was constructed by injecting acrylic resin into a two-part silicone matrix placed on a metallic base. In each specimen, the crowns were fabricated with either acrylic resin (control group) or acrylic resin reinforced by glass (Fibrante, Angelus) or polyaramide (Kevlar 49, Du Pont) fibers. Compression load was applied on the cantilever, in a point located 7, 14 or 21 mm from the distal surface of the nearest crown with abutment, to simulate different extensions. The specimen was fixed on the metallic base and the force was applied until fracture in a universal test machine. Each one of the 9 sub-groups was composed by 10 specimens. Flexural strength means (in kgf) for the distances of 7, 14 and 21 mm were, respectively, 28.07, 8.27 and 6.39 for control group, 31.89, 9.18 and 5.16 for Kevlar 49 and 30.90, 9.31 and 6.86 for Fibrante. Data analysis ANOVA showed statistically significant difference (p<0.05) only regarding cantilever extension. Tukey's test detected significantly higher flexural strength for the 7 mm-distance, followed by 14 and 21 mm. Fracture was complete only on specimens of non-reinforced groups.
authors.affiliation: Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Paola
authors.initials: P
authors.lastname: Colán Guzmán
authors.forename: Fernando Furtado Antunes de
authors.initials: FF
authors.lastname: Freitas
authors.forename: Paulo Martins
authors.initials: PM
authors.lastname: Ferreira
authors.forename: César Antunes de
authors.initials: CA
authors.lastname: Freitas
authors.forename: Kátia Rodrigues
authors.initials: KR
authors.lastname: Reis
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D003442:Crowns; D000044:Dental Abutments; D003764:Dental Materials / Q000737:chemistry*; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003779:Denture Design; D003833:Denture, Partial, Temporary; D005898:Glass / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D009757:Nylons / Q000737:chemistry*; D018583:Pliability; D011108:Polymers / Q000737:chemistry; D011312:Pressure; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials; D009757:Nylons; D011108:Polymers; C009753:fiberglass; C111780:polyaramide; C058852:Kevlar 49