Tiainen J (1), Veiranto M (2), Suokas E (3), Törmälä P
(2), Waris
T (4), Ashammakhi N (1)
1. Department of Surgery, Oulu University Hospital, P.O.
Box 22, FIN-90221
Oulu, Finland.
2. Institute of Biomaterials, Tampere University of Technology, P.O.
Box
589, FIN-33101 Tampere, Finland.
3. Bionx Implants Ltd., P.O. Box 3, FIN-33721 Tampere, Finland.
4. Department of Surgery, Tampere University Hospital and University
of
Tampere, Tampere, Finland
Oulu University Science Day, 18 Feb 2003, Oulu, Finland.
Aims
The aim of this study was to compare the pull-out forces of recently developed
bioabsorbable ciprofloxacin-containing and plain self-reinforced polylactide/polyglycolide
(SR-PLGA) miniscrews in human cadaver parietal bones.
Materials and methods
Parietal bone pieces (c. 6 cm x 20 cm) were collected from five human
male cadavers (44 to 75 years old). Fifty plain self-reinforced (SR-PLGA
80/20) miniscrews (diameter 1.5 mm, length 4.0 mm) and fifty ciprofloxacin-containing
SR-PLGA (80/20) miniscrews (diameter 1.5 mm, length 4.0 mm) were used
in this study. The force needed to pull the screws from human parietal
cadaver bones was measured using a tensile strength testing machine. The
screw pull-out speed was 10 mm/min. Means and standard deviations (SDs)
were calculated and analyzed using Student's t-test (SPSS version 10.0
for Windows).
Results
The pull-out forces of the ciprofloxacin-containing and plain miniscrews
were 66.8 ± 4.9 and 96.3 ± 9.3 N (significant difference, p<0.001), respectively.
The most common cause of failure was screw-shaft breakage (60% in the
case of ciprofloxacin-containing screws and 52% in the case of plain SR-PLGA
screws). Scanning electron microscopy (SEM) showed that the fibrillar
strip-like microstructure of plain SR-PLGA miniscrews turns into a coarse
uni-axial platelet-like morphology in antibiotic SR-PLGA miniscrews as
a result of the addition of ciprofloxacin.
Conclusion
Ciprofloxacin-containing SR-PLGA screws consequently have lower pull-out
strength than corresponding plain conventional SR-PLGA screws.
Keywords: Antibiotic, Bioabsorbable, Ciprofloxacin, Miniscrew,
SR-PLGA
