The role of torque device in implant retained mandibular overdenture prostheses (in-vivo and in-vitro study)‎

Abstract EN

Load transmission both at the bone-implant and within the implant-abutment prosthesis complex affects the behavior and longevity of implant-supported prostheses.

Hence the purpose of this study was to evaluate the role of torque devices (20 Ncm or 30 Ncm) in implant retained mandibular over denture prosthesis both in-vivo and in-vitro.

In-vivo study was performed in six male completely edentulous patients to evaluate the marginal bone loss for 18 months follow-up period using periodical radiograph with long-cone parallel technique.

In-vitro study was carried out in two sectors.

The first was to measure the microcap at the abutment-implant interface using scanning electron microscope.

The second was to record the stresses induced around the implant after abutment connection by the different torque wrench when a load 99 N was applied anteriorly or posteriorly on a model constructed especially for strain gauge analysis.

The results of this study revealed that ; the values of the marginal bone loss during all the follow-up intervals, the amount of the microcap and the stresses induced around the implant was lower when the abutment tightened to the implant using torque wrench 30 Ncm than torque wrench 20 Ncm.

There was a significant difference in the microcap values.

However these differences were not statistically significant for the marginal bone loss and the stresses induced around the implant.

Over a period of 18 months, we can concluded that the torque wrench play a prominent role in the amount of microcap at the abutment-implant interface and in the stresses induced around the implant that contribute for progressive bone loss after implant have been in function.