Torsion Strength of Biodegradable and Titanium Screws: A Comparison
Purpose
To determine 1) the differences in maximum torque between 7 biodegradable and 2 titanium screw systems, and 2) the differences of maximum torque between “hand tight” and break of the biodegradable and the titanium osteofixation screw systems.
Materials and Methods
Four oral and maxillofacial surgeons inserted 8 specimens of all 9 screw systems in polymethylmethacrylate plates. The surgeons were instructed to insert the screws as they would do in the clinic (hand tight). The data were recorded by a torque measurement meter. A PhD resident inserted 8 specimens of the same set of 9 screw systems until fracture occurred. Likewise, the maximum applied torque was recorded.
Results
1) The mean maximum torque of the 2 titanium screw systems was significantly higher than that of the 7 biodegradable screw systems, and 2) the mean maximum torque for hand tight was significantly lower than for break in 2 biodegradable, and both titanium screw systems.
Conclusions
Based on the results, we conclude that the 1.5 mm and 2.0 mm titanium screw systems still present the highest torque strength compared with the biodegradable screw systems. When there is an intention to use biodegradable screws, we recommend the use of 2.0 mm BioSorb FX (Linvatec Biomaterials Ltd, Tampere, Finland), 2.0 mm LactoSorb (Walter Lorenz Surgical Inc, Jacksonville, FL), or the larger 2.5 mm Inion (Inion Ltd, Tampere, Finland) screws.
⁎PhD Student, Department of Oral and Maxillofacial Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
†PhD Student, Department of BioMedical Engineering, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
‡Professor, Department of Oral and Maxillofacial Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
§Professor, Department of Oral and Maxillofacial Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
∥Professor, Department of BioMedical Engineering, University Medical Center Groningen, University of Groningen, Groningen; and Department of Biomechanical Engineering, University of Twente, Enschede, The Netherlands.
Address correspondence and reprint requests to Dr Buijs: Department of Oral and Maxillofacial Surgery, University Medical Center Groningen, University of Groningen, Hanzeplein 1, PO Box 30.001, 9700 RB Groningen, The Netherlands
ABSTRACT