Influence of the implant abutment types and the dynamic loading on initial screw loosening

Abstract

PURPOSEThis study examined the effects of the abutment types and dynamic loading on the stability of implant prostheses with three types of implant abutments prepared using different fabrication methods by measuring removal torque both before and after dynamic loading.MATERIALS AND METHODSThree groups of abutments were produced using different types of fabrication methods; stock abutment, gold cast abutment, and CAD/CAM custom abutment. A customized jig was fabricated to apply the load at 30° to the long axis. The implant fixtures were fixed to the jig, and connected to the abutments with a 30 Ncm tightening torque. A sine curved dynamic load was applied for 105 cycles between 25 and 250 N at 14 Hz. Removal torque before loading and after loading were evaluated. The SPSS was used for statistical analysis of the results. A Kruskal-Wallis test was performed to compare screw loosening between the abutment systems. A Wilcoxon signed-rank test was performed to compare screw loosening between before and after loading in each group (α=0.05).RESULTSRemoval torque value before loading and after loading was the highest in stock abutment, which was then followed by gold cast abutment and CAD/CAM custom abutment, but there were no significant differences.CONCLUSIONThe abutment types did not have a significant influence on short term screw loosening. On the other hand, after 105 cycles dynamic loading, CAD/CAM custom abutment affected the initial screw loosening, but stock abutment and gold cast abutment did not.

Abutment screw loosening of endosseous dental implant body/abutment joint by cyclic torsional loading test at the initial stage

“…This may be an indicator of the minimum standard for cyclic torsional loading test when carrying out the test under strict loading conditions, as in the present study. In addition, the number of loading cycles in the test was set at 100,000, in accordance with the estimates of Kim et al 14) regarding the number of cycles in one month following implant repair.…”

“…There have been clinical studies 2,3) , as well as numerous basic research studies [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] on abutment screw looseness, and reasons for looseness that have been put forward include insufficient fastening torque of the screw, unfitted components, inappropriate direction or position of implant placement, and poor occlusal status [4][5][6][7][8][9][10][11][12][13][14][15][16][17] . Looseness of the abutment screw causes poor fit of the superstructure, and can lead to fracture of the abutment screw and superstructure damage or detachment, as well as fracture of the implant or resorption of the periimplant bone.…”

Clinical Evaluation of 762 Single-Tooth, Locking-Taper Implants: A Prospective Study with 1- to 12-Years of Follow-Up

“…Screw loosening has been generally related to the type of implant/abutment connection used. Screw type connections, such as butt-joint indexed external or internal connections, are still the most commonly used in the market [18][19][20]. These connections are mainly stabilized by the axial preload of the abutment screw: as a consequence, optimum preload is critical for joint stability [18][19][20].…”

“…Screw type connections, such as butt-joint indexed external or internal connections, are still the most commonly used in the market [18][19][20]. These connections are mainly stabilized by the axial preload of the abutment screw: as a consequence, optimum preload is critical for joint stability [18][19][20]. The stability of butt-joint connections can be challenged by occlusal loads: when these exceed the resistance of the torqued implantabutment system, screw may loose or break [19,20].…”

Application of uniform design to improve dental implant system

“…Kayabasi, et al [3] investigated the stresses and strains on dental implant systems by using finite element analysis. Kim and Shin [4] revealed the effects of three abutment types and dynamic loading on the stability of implant prostheses. Mammadzada, et al [5] investigated the effect of abutment and implant shapes on stresses in dental applications.…”