Multiple-unit implant frames: one-piece casting vs. laser welding and brazing.
The linear distortion of prostheses over implants, one-piece casting and cast in sections followed by laser welding by laser and brazing was evaluated in an edentulous mandibular model with five parallel abutments, with a distance of 10mm from center to center. Seventy five gold cylinders were tightened with screws on the abutments with 10Ncm torque. The cylinder/analogue assemblies were measured by microscopic examination (0.001mm accuracy) and the obtained results were compared with the GC (control group). Fifteen metal frames were waxed and cast in a gold alloy (Stabilor, Degussa Hulls, Brazil) and divided into three groups with five elements each, as followed: GM (one-piece casting), GB (section and brazing) and GL (section and laser welding). In all groups, measurements were taken at the right, left, buccal and lingual sides of the cylinder/analogue interface and the results were submitted to analysis of variance (ANOVA) and to the Tukey test (5%). The smallest amount of distortion was seen in the laser group (GL with a mean value of 13.58), followed by the brazing group (GB with a mean value of 24.33) and one-piece (GM with a mean value of 40.00). The greatest distortion was found in the one-piece group (GM).
Department of Prosthodontics and Dental Materials, Dental School, Universidade Estadual Paulista, São José dos Campos, São Paulo, Brazil.
Elza Maria Valadares da
EM
Costa
Maximiliano Piero
MP
Neisser
Marco Antônio
MA
Bottino