Mechanical stability and clinical applicability assessment of novel orthodontic mini-implant design

Abstract

Objective: To compare the stability and clinical applicability of a novel orthodontic mini-implant design (N2) with the most widely used commercially available (CA) design. Materials and Methods: Two groups of mini-implants were tested: a CA design (1.5-mm diameter, 6-mm length) and N2 (3-mm diameter, 2-mm length, tapered shape). Implants were inserted in bone blocks of cortical bone simulation with varying densities (20 pounds per cubic foot [pcf], 30 pcf, and 40 pcf). A torque test was used to measure maximum insertion torque (MIT) and maximum removal torque (MRT). Compression and tension force vectors were applied at angles of 10u, 20u, 30u, and 40u using customized load pins to determine primary stability. Results: Mean MIT and MRT were higher in the N2 than the CA design at all three cortical bone densities except MRT in 20 pcf bone (not statistically significant). The mean compression force required to displace the N2 at all distances and angulations was greater for the N2 than the CA design. At all displacement distances, the highest mean tension force required for N2 displacement was at 10u angulation, whereas at 30u and 40u, the mean tension force required to displace the CA design was greater. Conclusions: The primary stability of the N2 is superior to that of the CA design and is promising for both orthodontic and orthopedic clinical applicability, especially under compression force. The short length of the N2 reduces risk of damage to anatomic structures and root proximity during placement and orthodontic treatment. The stability of the N2 may be compromised in areas of high bone density and highly angulated tension force. (Angle Orthod. 2013;83:832-841.)

Effects of monocortical and bicortical mini-implant anchorage on bone-borne palatal expansion using finite element analysis

“…Mini-implant loss and loosening rates for orthodontic tooth movement ranges from 6.9–28.0%, and their success is dependent on several factors which include the magnitude and direction of the applied force; operator experience; insertion site; quality of cortical bone; surface contact area in cortical bone; length, depth, diameter, thread configuration and shape of the mini-implant; and patient’s age. 26–35 While there have not been any specific reports analyzing mini-implant failure rates during bone-borne expansion in mature patients, such failure rates are likely to be higher than in orthodontic tooth movement due to the increased magnitude of the applied force necessary to split the interlocking suture. Therefore, new approaches to improve mini-implant stability during bone-borne expansion are needed.…”

Comparison of mechanical and biological properties of zirconia and titanium alloy orthodontic micro-implants

“…Considering that variations in micro-implant design and bone density result in a diversity of insertion torques,21 torque tests have been conducted on a range of simulated cortical bone densities because the density of bone varies depending on its location 9. Furthermore, removal torque has proved a reliable measure of stability, and should be comparatively high to prevent unscrewing 22.…”

“…The surgical engine was calibrated before testing, and rotational speed was set to 30 rpm. The polyurethane foam was composed of cortical bone simulant of 2-mm thick 20, 30, and 40 pounds per cubic foot (pcf),9 and the trabecular bone part was composed of 10 pcf (Table 2). Soft tissue was simulated with a 1-mm thick plastic sheet covering.…”

“…The polyurethane foam with micro-implants was positioned to deliver a force to the neck of the micro-implants with varying angulations of 0°, 10°, 20°, 30°, and 40° with respect to the line perpendicular to the long axis of the micro-implants, fixed in a vice. Lateral displacement testing was then performed using compressive and tensile modes of a universal testing machine (Instron 4465; Instron, Norwood, MA, USA) with customized loading pins 9. Software (Bluehill® version 2.0; Instron) was used to record the force value with a 1 kN load cell when implants were displaced by 0.01, 0.02, and 0.03 mm from their original position.…”

Development of a novel spike-like auxiliary skeletal anchorage device to enhance miniscrew stability

“…[24][25][26][27][28][29] Two groups comprising 10 miniscrews each were implanted en masse into artificial bone blocks using a driver machine (Orthonia 111-ED-010; Jeil Medical); 1 group was implanted with an auxiliary skeletal anchorage device (auxiliary group) and 1 without the auxiliary device (nonauxiliary group). The spiked portion of the auxiliary skeletal anchorage device was implanted into the cortical region of the artificial bone to a depth of 0.3 mm.…”