title: Photoelastic stress analysis in screwed and cemented implant-supported dentures with external hexagon implants.
abstract: The aim of this study was to assess the stress distribution of the retention systems (screwed and cemented) for implant-supported fixed partial dentures by means of photoelastic method. Two models were made of photoelastic resin PL-2 with 2 implants (phi = 4.00 x 10 mm) located in the second premolar and molar region in each photoelastic model, varying the retention system (screwed and cemented). The implant-supported fixed partial dentures were standardized and made of Ni-Cr alloy. Axial and oblique (45 degrees) forces of 100 N were applied on the occlusal surface by means of a Universal Testing Machine (EMIC-DL 3000; São José dos Pinhais, Paraná, Brazil). The results were observed and photographed in the field of a circular polariscope and qualitatively analyzed with the aid of computer software (Adobe Photoshop, San Jose, CA). The screw retention system presented the highest number of fringes when the loads were applied on the premolar, pontic, and molar and showed this behavior in all load applications, under axial and oblique loads. It was concluded that there was a better stress distribution and lower magnitude of stress on the cemented implant-supported dentures, under axial and oblique loads. Oblique load caused an increase in stress concentrations in all the models.
authors.affiliation: Department of Dental Materials and Prosthodontics, Araçatuba School of Dentistry, São Paulo State University-UNESP, Araçatuba, São Paulo, Brazil. ed.pl@uol.com.br
authors.forename: Eduardo Piza
authors.initials: EP
authors.lastname: Pellizzer
authors.forename: Bianca Piccolotto
authors.initials: BP
authors.lastname: Tonella
authors.forename: Renato
authors.initials: R
authors.lastname: Ferraço
authors.forename: Rosse Mary
authors.initials: RM
authors.lastname: Falcón-Antenucci
authors.forename: Paulo Sérgio Perri
authors.initials: PS
authors.lastname: de Carvalho
authors.forename: Maria Cristina Rosifini
authors.initials: MC
authors.lastname: Alves-Rezende
mesh_terms: D001696:Biomechanical Phenomena; D001732:Bite Force; D002484:Cementation; D003722:Dental Alloys; D015921:Dental Implants; D017268:Dental Prosthesis Retention / Q000295:instrumentation*; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000379:methods*; D003779:Denture Design; D003830:Denture, Partial, Fixed; D003765:Models, Dental
chemical_list: D003722:Dental Alloys; D015921:Dental Implants