Correlation between vertical misfits and stresses over implants from castable frameworks made of different alloys

• Published in: The Journal of craniofacial surgery Vol. 25; no. 6; p. 2062
• Main Authors: Barbosa, Gustavo Augusto Seabra, Bernardes, Sérgio Rocha, de França, Danilo Gonzaga Bernardo, das Neves, Flávio Domingues, de Mattos, Maria da Glória Chiarello, Ribeiro, Ricardo Faria
• Format: Journal Article
• Language: English
• Published: United States 01.11.2014
• Subjects: Analysis of Variance; Biomechanical Phenomena; Chromium Alloys - chemistry; Cobalt - chemistry; Dental Abutments; Dental Alloys - chemistry; Dental Casting Technique; Dental Prosthesis, Implant-Supported; Elasticity; Humans; Mandible - anatomy & histology; Mandible - physiology; Prosthesis Design - methods; Titanium - chemistry
• ISSN: 1536-3732
• DOI: 10.1097/SCS.0000000000001194

This study aims to investigate a possible correlation between vertical misfits and the stresses transmitted to implants from one-piece casted frameworks fabricated with 3 different materials: commercially pure titanium, cobalt chromium alloy, and nickel chromium titanium alloy. Twelve frameworks simulating screw-retained prosthesis were fabricated from a master cast with 5 implants. Each framework was screwed (20 Ncm) over a metal cast and the vertical mesial and distal misfits were measured using an optical microscope. The stresses transmitted to the implants were measured in a third model by a quantitative photoelastic analysis. Stress and vertical misfit data were statistically analyzed by ANOVA and least significant difference tests and the correlation tests were performed using Pearson Correlation Test (α = 0.05). Mean and standard deviation values of vertical misfit and stress over implants are presented, respectively: commercially pure titanium (29.09 ± 13.24 μm and 11.38 ± 9.23 kPa), cobalt chromium alloy (27.05 ± 10.30 μm and 15.83 ± 9.30 kPa), nickel chromium titanium alloy (24.95 ± 11.14 μm and 16.39 ± 9.51 kPa). There were no significant differences for vertical misfit (P = 0.285). Regarding the stress analysis, there were significant differences between commercially pure titanium, cobalt chromium alloy, and nickel chromium titanium alloy (P = 0.035), with the lowest values for the commercially pure titanium. It may be concluded that stress over implants was affected by different procedures and materials for framework production.