Reliability of Orthodontic Miniscrews: Bending and Maximum Load of Different Ti-6Al-4V Titanium and Stainless Steel Temporary Anchorage Devices (TADs)

Abstract

Temporary anchorage devices (TADs) have been introduced into orthodontic clinical practice in order to allow tooth movements while avoiding strain on adjacent teeth. Miniscrews are available in the market with different diameters and materials. Accordingly, the purpose of the present report was to measure and compare the forces to bend and fracture different mini implants. Ti-6Al-4V titanium and stainless steel TADs of different manufacturers (Spider ScrewHDC; Mini Implants–Leone; Benefit–Orteam; Storm–Kristal) were evaluated. Two different diameters (1.5 mm and 2.0 mm) were tested. The sample included 10 unused specimens for each group, blocked in an Instron Universal Testing Machine, and a shear load was applied at the neck of the miniscrew. The force to bend the miniscrew was measured at 0.1 mm and 0.2 mm deflections. Also, the maximum force before screw fracture was recorded. Data were submitted for statistical analysis. Results showed significantly higher forces for 2.0 mm than 1.5 mm screws, both at 0.1 mm and 0.2 mm deflections and at maximum load. Moreover, no significant differences were reported between titanium and stainless steel miniscrews of equal diameters.

Stainless steel or titanium mini-implants?

“…The lowest success rate found for SS MIs was 50%, 14 and the highest was 100%. 15 Regarding Animal study Carano et al (2005) In vitro study Chen et al (2018) In vitro study Gritsch et al 2013Animal study Khan et al (2016) No use of both types of mini-implants Kliauga et al 2010In vitro study Natarajan et al 2017Studies not related with the research objective Pan et al 2012In vitro study Scribante et al (2018) In vitro study Tseng et al 2016In vitro study Tseng et al 2017In vitro study Tseng et al 2017In vitro study titanium MIs, the lowest success rate found was 84.46%, 20 and the highest was 100%. 15 Only one study reported that titanium MIs showed higher success rates than SS MIs and that a higher implant failure was found in the upper jaw when compared with the lower jaw.…”

“…26,28 SS MIs are also used in orthodontics and present great mechanical properties and better resistance to breakage and penetration capability. 9,10,26 Some in vitro and animal studies have shown that the two materials present similar results with respect to fracture strength and torsion, 29 mechanical stability, and histological responses. 8…”

Multifunctional Templates for Minimized Osteotomy, Implantation, and Palatal Distraction with a Mini-Screw-Assisted Expander in Schizodontism and Maxillary Deficit

“…Even after transverse expansion with a conventional removable expansion plate and pulling of the attached upper first incisors against it, the plate would not have provided support due to the beginning of tooth change in the second mixed dentition. Mini-screw-assisted palatal expanders are supported with titanium [ 13 ], stainless steel [ 14 ], or orthodontic miniscrews, like the used bone-borne apparatus (IGPD). In addition, anchoring by implants offers the advantage that neither the setting of the incisors nor the palatal expansion is dependent on the compliance of the young patient.…”

Imaging Software Programs for Reliable Mathematical Measurements in Orthodontics

“…This concern is particularly important when planning miniscrew assisted palatal expanders or other miniscrew supported orthodontic devices with a completely digital workflow [ 32 ]. In these cases, the accuracy of the measurements is particularly important, thus allowing the clinician to choose diameter and type of miniscrew as these characteristics have a great influence on the mechanical behavior of the screws [ 33 , 34 ].…”