title: Misfit of pure titanium frameworks: effect of veneer coverage and spark erosion process.
abstract: OBJECTIVE. The purpose of this study was to evaluate the influence of veneer application on the misfit level of implant-supported frameworks. MATERIALS AND METHODS. Thirty commercially pure titanium (Tritan, Dentaurum, Pforzheim, Germany) frameworks were fabricated from a metallic index containing five Branemark-type multi-unit abutments. Analogs of the abutments were positioned into the framework to manufacture an index for each framework, which permitted the evaluation of the marginal gap caused only by the veneer coverage. The frameworks were grouped (n = 10) in the following manner: (G1) heat-cured acrylic resin (Clássico, Clássico, São Paulo, Brazil); (G2) light-cured resin (Versyo.com, Heraeus Kulzer, Brazil); and (G3) porcelain (Triceram, Dentaurum, Pforzheim, Germany). Marginal refinement with spark erosion was then conducted. The marginal gap was verified before and after the veneer coverage and the spark erosion procedure, following the single screw test protocol (tightening force of 10 Ncm). Data were submitted to an analysis of variance (ANOVA) in a split-plot design for repeated measurements followed by a Tukey test (p = 0.05). RESULTS. The veneer application was associated with a significant increase in the mean misfit values of all groups. The lowest values were presented by G2. After the spark erosion process, the mean misfit value decreased only on G3. CONCLUSIONS. Heat-cured acrylic resin and porcelain produced the highest values of marginal gaps, whereas light-cured acrylic resin produced the lowest. In addition, the spark erosion process was effective only in the marginal gap of the porcelain application group.
authors.affiliation: Department of Prosthodontics and Periodontology , Piracicaba Dental School, Campinas State University, São Paulo, Brazil.
authors.forename: Marcia Mika
authors.initials: MM
authors.lastname: Nakaoka
authors.forename: Juliana Maria Costa
authors.initials: JM
authors.lastname: Nuñez-Pantoja
authors.forename: Jessica Mie Ferreira Koyama
authors.initials: JM
authors.lastname: Takahashi
authors.forename: Rafael Leonardo Xediek
authors.initials: RL
authors.lastname: Consani
authors.forename: Marcelo Ferraz
authors.initials: MF
authors.lastname: Mesquita
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000044:Dental Abutments; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D019094:Dental Prosthesis, Implant-Supported; D003801:Dental Veneers; D055664:Electrochemical Techniques; D006801:Humans; D008422:Materials Testing; D012117:Resins, Synthetic / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D019415:Torque
chemical_list: D000180:Acrylic Resins; D003764:Dental Materials; D012117:Resins, Synthetic; D003776:Dental Porcelain; D014025:Titanium