Mechanical properties of three different commercially available miniscrews for skeletal anchorage.
BACKGROUND
During the last 5 years, anchorage control with self-tapping miniscrews has become an important part of the clinical management of orthodontic patients. Yet, no studies have been performed for measuring mechanical properties of the currently available systems.


OBJECTIVE
The purpose of this study is the evaluation of mechanical properties of three commercially available self-tapping screw systems used in orthodontic treatment.


METHODS
three systems with a 1.5 mm diameter and 11 mm length screw (Leone, Firenze, Italy; M.A.S. Micerium, Avegno, Italy; Dentos, Korea) were examined. The results compared the resistance to bending, torque, pullout of each screw and the insertion moments needed to screw down each sample.


CONCLUSIONS
All three miniscrews have mechanical properties that contribute to their safe use as skeletal anchorage in orthodontics. Although stainless steel has demonstrated to be more resistant to failure than titanium, its overall performance as material for miniscrews could be inferior to titanium. In order to facilitate the insertion, the asymmetric profile of the thread should be preferred to the symmetric cut. The ratio between the diameter of the drill and the diameter of the corresponding miniscrew is pivotal for the successful implantation and resistance of the miniscrews. Looking at the mechanical properties evaluated in this study, a cylindric shape of the screw is better than a conic one. The conic shape could be preferred in case the site of insertion is iterradicular and therefore limited to 2.5-3.5 millimetres.
Carano
Aldo
A
Department of Orthodontics, University of Ferrara, Ferrara, Italy.
Lonardo
Pietro
P
Velo
Stefano
S
Incorvati
Cristina
C
D001863:Bone Screws; D003722:Dental Alloys; D003758:Dental Implantation, Endosseous / Q000379:methods; D003799:Dental Stress Analysis; D016382:Orthodontic Appliance Design; D009967:Orthodontic Appliances; D018583:Pliability; D013193:Stainless Steel; D014025:Titanium; D019415:Torque
D003722:Dental Alloys; D013193:Stainless Steel; D014025:Titanium