The effect of repeated torque tightening on total lengths of implant abutments in different internal implant‒abutment connections

Abstract

Background. Since the misfit of crown has an important role in clinical performance of implant-supported prostheses, and due to the impact of the settling effect on misfit, the aim of this study was to investigate the impact of torque forces on the total lengths of narrow and short implant abutments in different internal implant‒abutment connections. Methods. In four different implant‒abutment connections, 8 analog implants with a normal diameter (4 mm) and narrow abutment (4.5 mm) were selected from groups of internal hex, internal octagon, morse hex 6° and morse hex 11°. Each of them was mounted within plaster type IV, and 32 samples were obtained. Then, the amount of vertical displacement was measured by closing the impression copings and applying torques of 20 25 and 30 Ncm. This stage was repeated for the abutment. In the next stage, the resin pattern was built and measurements were performed after applying the torques mentioned. Finally, after making the frame, this stage was repeated, and the settling effect was statistically analyzed with ANOVA. Results. In the stages of impression coping, resin pattern and final prosthesis, HEXAGONE had significantly the highest and OCTAGONE had the lowest rates of settling, and the settling of morse hex 11° and 6° was between them. Conclusion. Octagon implant had significantly the lowest settling in various clinical and laboratory stages by applying different torques.

Biological Responses to the Transitional Area of Dental Implants: Material- and Structure-Dependent Responses of Peri-Implant Tissue to Abutments

“…The abutment screw becomes slightly loosened when the abutment is completely combined with the implant by opening the implant wall. Because of the preload loss from such an abutment sinking and settling effect, repeated screw tightening is essential [18,22].…”

Vertical Discrepancy in Height of Morse Cone Abutments Submitted to Different Torque Forces

“…On the other hand, the use of different torques on analogs and implants did not influence the height of the prosthetic abutment, showing that the use of the analog during the prosthesis fabrication is not directly related to future mismatches associated with the crown height but rather the applied torque. A study by Saber et al [ 7 ] showed the discrepancy of the abutment height between the different types of implant platforms, showing greater discrepancy in the external hexagon system. However, in the present study, we did not consider the simulation of the laboratory phase of prosthesis confection, using analog, as done in our study.…”

“…Microsoft Office 2013 Excel was used for data tabulation and Prisma GraphPad 6.0 software was used for statistical calculations and graphic production. The sample size was based on previous studies [ 7 , 8 ], considering the power of 80%.…”

“…Since crown misalignment and adaptation between implant and abutment could impact the clinical performance of implant-supported prosthesis, it is up to the professional to understand the stages of the screw–implant prosthesis connection [ 7 ]. To minimize the screw loosening, it is documented in the literature that the screw should be retightened at least twice at 10-min intervals in all laboratory and clinical procedures [ 8 ].…”

Three interfaces of the dental implant system and their clinical effects on hard and soft tissues

“…This is because the implant top is gradually opened, causing the abutment to sink down, which loosens the abutment screw, leading to a need for periodic retightening. 175,241,242 Otherwise, abutment movement increases, leading to destruction of the soft tissue seal, and subsequent bacterial attack. Clinically, re-tightening can be performed several times if necessary.…”