Avaliação do destorque do parafuso protético de diferentes tipos de conexões com coroas longas

Abstract

The aim of this study was to evaluate the influence of different connections in detorque Neotorque screw implant with crown ratio - implant (2:1), in vitro study, after mechanical cycling. Thirty of 9 mm x 3.75 mm (Neodent®-Curitiba, Paraná, Brazil) were utlizados implants, 10 of each connection type (CM, HE, HI) with their universal posts: (CM) ( 3, 3/6 / 3,5), HE and HI ( 4,5,6,3) (Neodent®-Curitiba, Paraná, Brazil). The implants were inserted individually in acrylic resin (JET, Classic, São Paulo, Brazil) using a standardized burn-cylinder ( 2,5x1,5). The torque on the bolts was done with digital torque meter (Lutron TQ - 680, Impac, São Paulo), the HE group received 30 N.cm, the CM group and 15 N.cm the HI group 20N.cm. Subsequently the application of torque, the crowns were placed on the abutments with petrolatum (Farmax, Divinópolis, Brazil) and then were subjected to mechanical cycling (Simulator Mechanical Stress, Erios, ER Model - 11000), with application of a 120N load, 75 cycles / sec per 1 million cycles at 1 Hz, immersed in distilled water. Finally, the detorque was measured with the aid of a digital torque meter (Lutron TQ-680, Impac, São Paulo / SP). The (standard deviation) values of average detorque obtained after mechanical cycling were: CM - 13.4 (1.83) N.cm, HI - 17 (1.69) and HE N.cm - 25.6 (1, 95) N.cm. The ANOVA test (p <0.05) showed no statistically significant difference between groups (p = 0.526) with respect to different types of abutment connection - implant and the crown ratio (2) - implant (1) after cycling mechanics. To evaluate whether each group compared to the pressure drop in torque after mechanical closure cycling, independent Student t (p <0.05) was performed, there was a statistically significant result for loss of initial torque in each group : CM (0.022), HI (0.00) and HE (0.00). It was concluded that the type of abutment connection - implant and crown ratio - implant (2: 1) no effect on the loss of torque after mechanical cycling; mechanical cycling effect on the loss of torque within each group of connection pillar - implant.