Evaluation of the accuracy of Spring type and Toggle design torque wrenches used in implant dentistry

Abstract

Background/aim: Dental implants have grown exponentially in modern dentistry. Although the success rate of implant treatments is generally high but outbreak of prosthodontics and surgical complications are not uncommon in implant-supported prostheses. Loosening of abutment screw is the most common complication in dental implants , one of the causes of making this problem is the inaccuracy of the desired torque wrenches. Therefore, in this study, the accuracy of two Spring type and Toggle design torque wrenches used in implant dentistry was evaluated and compared. Materials and Methods: In this descriptive-analytical study, the accuracy of two types of torque wrenches, spring type Dentis Company (DENTIS Co, Seoul, South Korea) and Toggle Design SIC (SIC invent AG, Basel, Switzerland) ,was investigated. From each of torque wrenches 6 were prepared (12 in total). As to determine the value of torque wrench’s accuracy, in the torque which was determined in the producing factory of device , a digital torque meter (TQ-8800, Lutron, Taiwan) was used. And for the Toggle Design in two torque ranges of 10 N.cm and 30 N.cm, and for the spring type in two torque ranges of 15 N.cm and 35 N.cm , each torque was applied thirty times (for every 12 wrenches) by an operator, and each time the algebraic difference between displayed torque on the device monitor with the number on the corresponding torque wrench was calculated. Then, the accuracy of the wrenches was calculated and compared in the high and low torque range. The results of the study were evaluated using descriptive statistics (mean ± SD) using SPSS17 software and a significant level of P <0.05 was considered. findings: Average error percentage of spring type wrench in low torque range (15 N.cm) is 15.74 ± 4.26%, and in the high torque range (35 N.cm) is 5.06 ± 2.10% and the average error percentage of Toggle design wrench in low torque range (10 N.cm), is 14.66 ± 2.44%, and in the high torque range (30 N.cm), is 7.96 ± 2.10%. In general, the average error occurred in two types of wrenches (in Newtons Centimeter), is noticeable that the highest mean is related to the Toggle design wrench with an average of 11.31 ± 4.12 and the lowest value is related to the Spring type wrench with an average of 10.40 ± 6.43. Also, in each of the two tested wrenches, the highest percentage of error is related to the low torque range. Results: According to this study, in general, all the examined wrenches in the low torque range, have higher error rate, and in the high Torque range, the error is lower. Although the type of wrench affects the torque error , But this error depends on several other factors and it's not just related to the type of wrench. Also according to the results of this study, there is no significant statistical difference between the mean error of Spring type and Toggle design wrenches.