Influence of the ultimate torsion on the geometry of dental implants.

This study evaluated the profile of implants subjected to torsion test. Four types of implants (Conexão®) were analyzed: Master Porous (MP - external hexagon, cylindrical, double-porous surface implants; 11.5 X 3.75 mm), Master Screw (MS - external hexagon, cylindrical, machined implants; 11.5 X 3.75 mm), Conect Conic (CC - external hexagon, cylindrical, machined implants; 11.5 X 3.5 mm) and Master Conect AR (CA - internal hexagon, cylindrical, double-porous surface implants; 11.5 X 3.75 mm). The Nikon® model C profile projector was used for the analysis before and after torsion test with a Mackena® model MK-20XX digital torque meter. The measures analyzed in the profile of implants were: diameter and height of the platform, diameter of the screw/platform connection, angle of the screw/platform connection, external diameter, internal diameter, thread pitch, height and length of the thread. Statistical analysis was performed using ANOVA and Tukey test at 5% significance level. The torsion test caused a visible deformity on the external implant profile. There was a statistical difference among the implants before and after torsion (p<0.05) for the variables: platform diameter, platform height, diameter of the screw/platform connection and length. Changes were observed in platform height of CC and CA, fracture of CA implants, fracture of the MP and MS assembler/connectors, and internal thread stripping of CC. Thus, it was concluded that excessive or some unadvised torque by the manufacturer can lead to changes in different geometric measurements of implants.