title: Evaluation of the adaptation interface of one-piece implant-supported superstructures obtained in Ni-Cr-Ti and Pd-Ag alloys.
abstract: Several formulations of alternative alloys have been proposed for the substitution of gold-based alloys used in Dentistry. Recently, a Ni-Cr-Ti-based alloy has been introduced. The purpose of this work was to verify the marginal adaptation obtained with one-piece superstructures for implant-supported prostheses obtained in Ni-Cr-Ti alloy, compared to a semi-noble alloy Pd-Ag. Eight superstructures for each alloy were produced over 4 implants in the anterior region of the mandible. The superstructures were placed in a torquemeter and the fixation screw of implant #1 was tightened with a 20 Ncm load with the others loosened (Sheffield test). The unfitness (in mm) was measured using a three-dimensional optical measurer in each implant, in the buccal and lingual aspects. The obtained data were submitted to statistical analysis by the analysis of variance and Tukey's test at 5% level. Significant differences were found for the factors material (p< or =0.05), with Ni-Cr-Ti pieces better than Pd-Ag ones, and implants (p< or =0.01). There were no significant differences for the factor position and interactions among factors (p>0.05). Based on the analysis of the data, it is possible to conclude that the Ni-Cr-Ti alloy makes possible the obtainment of one-piece implant-supported superstructures with a smaller misfit compared to the one obtained in Pd-Ag alloy, traditionally indicated for this situation. Additional tests may verify the superiority of the Ni-Cr-Ti alloy.
authors.affiliation: Department of Dental Materials and Prosthesis, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Heloisa Módena Ferreira da
authors.initials: HM
authors.lastname: Costa
authors.forename: Renata Cristina Silveira
authors.initials: RC
authors.lastname: Rodrigues
authors.forename: Maria da Glória Chiarello de
authors.initials: Mda G
authors.lastname: Mattos
authors.forename: Ricardo Faria
authors.initials: RF
authors.lastname: Ribeiro
mesh_terms: D002858:Chromium Alloys / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D019094:Dental Prosthesis, Implant-Supported; D006801:Humans; D021621:Imaging, Three-Dimensional; D008422:Materials Testing; D010165:Palladium / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D019415:Torque
chemical_list: D002858:Chromium Alloys; D003722:Dental Alloys; D015921:Dental Implants; D012834:Silver; D010165:Palladium; D014025:Titanium