Comparison of the Effect of Four Different Abutment Screw Torques on Screw Loosening in Single Implant-Supported Prosthesis after the Application of Mechanical Loading

Abstract

Background. The complications of implant-supported prostheses can be classified into mechanical and biological ones, one part of which is associated with screw loosening. This study was aimed to compare the effect of four different abutment screw torque techniques on screw loosening in single implant-supported prostheses following the application of mechanical loading. Materials and Methods. In this experimental study, a total of 40 implants in acrylic blocks (6 × 10 × 20 mm) were mounted perpendicular to the surface. They were then randomly divided into four groups: (1) torquing once with 30 Ncm, (2) torquing three times with 30 Ncm and 5-minute intervals, (3) torquing once with 30 Ncm, opening the screw, and retorquing with 30 Ncm, and (4) torquing once with 35 Ncm. The torque values were confirmed by using a digital torque meter. Then, the samples underwent a force (2 cps, 0.453–11.793 kg) for three hours before the measurement of detorque values. The screw loosening force (torque) was then measured and recorded. The obtained data were analyzed by SPSS (version 22) software using one-way ANOVA and Tukey post hoc test at a 5% error level. Results. The maximum mean detorque values of the abutment screws in single implant-supported prostheses were reported for groups 4 (27.8 ± 1.3), 1 (26.8 ± 1.3), and 3 (25.1 ± 1.3), and the minimum mean detorque value was found in group 2 (24.9 ± 1.2). Moreover, no significant difference was observed between groups 2 and 3 ( p > 0.05 ), but a significant difference was found between groups 1 and 3 and other groups ( p < 0.05 ). Conclusion. The increase in the torque value increased the torque loss. However, the detorque value in group 4 showed the least difference with the value recommended by the manufacturer (30 Ncm).

Deformation of implant retaining screws—Study with stereoscopic microscopy and microCT

“…Our results are in agreement with the findings of Kim et al which report that when the number of tightening and loosening (cycles) was increased, the wear also was more severe 19 . Similarly, Ebadian et al when testing screw torque techniques showed that when increasing the insertion torque multiple cycles a decrease in mean abutment screw detorque can be expected 21 …”

“…when testing screw torque techniques showed that when increasing the insertion torque multiple cycles a decrease in mean abutment screw detorque can be expected. 21 One of the limitations of this study was the fact that for microCT we examined only one screw of each group and that a certain intragroup variability can be expected. In vivo conditions have multiple factors (e.g., saliva, wrench key angulation, sealant materials) that were not present in our investigation.…”

“…Although the design of the head and its section has evolved to the hexagonal, there are very limited studies evaluating the wear and deformation of the section of the head of the retaining screw after torque application, which deserves to be addressed and became the subject of study. Most of studies found in literature assess torque, wear of screw thread morphology or implant connection 6,13,18–21 …”

“…Most of studies found in literature assess torque, wear of screw thread morphology or implant connection. 6,13,[18][19][20][21] This investigation consisted in the assessment of the deformation of the implant retention screw head using two different methods.…”

Drug delivery and anticancer activity of biosynthesised mesoporous Fe2O3nanoparticles

“…Therefore, research and development of new cancer treatment methods are needed [12][13][14]. New developments in science and technology have significant impact on human health [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] and life [30][31][32][33][34][35][36].…”