Evaluation of mechanical strengths of three types of mini‐implants in artificial bones

Abstract

We investigates the effect of the anchor area on the mechanical strengths of infrazygomatic mini-implants. Thirty mini-implants were divided into three types based on the material and shape: Type A (titanium alloy, 2.0×12 mm), Type B (stainless steel, 2.0×12 mm), and Type C (titanium alloy, 2.0×11 mm).The mini-implants were inserted at 90° and 45° into the artificial bone to a depth of 7 mm, without predrilling. The mechanical strengths [insertion torque (IT), resonance frequency (RF), and removal torque (RT)] and the anchor area were measured. We hypothesized that no correlation exists among the mechanical forces of each brand. In the 90° tests, the IT, RF, and RT of Type C (8.5 N cm, 10.2 kHz, and 6.1 N cm, respectively) were significantly higher than those of Type A (5.0 N cm, 7.7 kHz, and 4.7 N cm, respectively). In the 45° test, the RFs of Type C (9.2 kHz) was significantly higher than those of Type A (7.0 kHz) and Type B (6.7 kHz). The anchor area of the mini-implants was in the order of Type C (706 mm)>Type B (648 mm)>Type A (621 mm). Type C exhibited no significant correlation in intragroup comparisons, and the hypothesis was accepted. In the 90° and 45° tests, Type C exhibited the largest anchor area and the highest mechanical strengths (IT, RF, and RT) among the three types of mini-implants. The anchor area plays a crucial role in the mechanical strength of mini-implants.

Mechanical Properties of Mini-Implants Used in Extra-Radicular Anchorage

“…Considering that primary stability is one of the key factors for the clinical success of MIs [8,[10][11][12][13], its evaluation can be performed using methods such as periotest, pull-out and insertion/removal torque. It is defined as mechanical bone stability immediately after MI insertion [14][15][16][17] and it should be noted that cortical bone is an important factor in MI stability [11,14,15,17,18]. The present study observed that the primary stability of 12×2.0 mm steel MIs was superior to the other evaluated MIs.…”

“…In the present study, percussion test evaluation did not reveal significant differences among the groups evaluated. However, in the study by Tseng et al [17], 2.0×11 mm titanium MIs showed higher resonance values than 2.0×12 mm titanium MIs and 2.0×12 mm steel MIs.…”

“…Modifications in MI design can substantially affect their mechanical properties [10]. In contrast, for Tseng et al [17], long-term MI stability was not directly affected by design. MI fractures are usually generated by torsional stress caused by their small diameter [1,26].…”

“…The insertion torque measurement is an important parameter related to the MI primary stability [4,15,17,19,20]. MI dimensions influenced the insertion torque values, considering that the larger the MI diameter, the higher the insertion torque values.…”

Choice of Screws for Fixation of Mandibular Condyle Fractures Guided by Anthropometric Data

“…When considering the issue of the length of screws fixing the plates, it should be noted that the longer the screws used, the stronger they anchor in the bone and stabilize the osteosynthesis [31][32][33]. The longer the screw, the more stable the fixation, even for plateless osteosynthesis [34,35].…”