Comparison of fixation stability of resorbable versus titanium plate and screws in mandibular angle fractures

ABSTRACTComparison of Fixation Stability of Resorbable versus Titanium Plate and Screws inMandibular Angle Fractures.To date many fixation techniques of mandibular angle fractures have been developed. There existmany research on the stability of plate and screws systems used in Champy technique in fixationof mandibular fractures . However the need of a second surgery for the removal of these platesand screws, and well known disadvantages of metallic fixations have led to the development ofresorbable materials. It is thought that in order to achieve a safe and effectual post operativestability, the use of resorbable plates and screws can be preferred for fixation. This study wasaims to compare the fixation reliabilities and stabilities of titanium and resorbable (Inion) platesand screws by simulating the chewing forces in the first 6 weeks of the post-operative period inwhich the ossification should be mostly completed after fixation of mandibular angle fractures.For this purpose, mandibular angle fracture was performed on 22 sheep hemi-mandibles and 11hemi-mandibles were fixed with 4 hole straight titanium plates and 2.0 x 7 mm titanium screwsand the other 11 hemi-mandibles were fixed with 4 hole straight resorbable plates and 2.5 x 6 mmresorbable screws (Inion) in Champy technique. Subsequently with a fixation apparatus, all hemi-mandibles were mounted in a servohydraulic testing unit to perform a shear test until a permanentdeformation. Displacement values were recorded digitally by special software. Maximum forcesthat the model could resist before breakage (N), maximum displacements of the model and thedisplacement values under 20,60, 100, 120, 150, 200 N were compared. A statistically significantdifference between resorbable and titanium plates and screws was observed up to applied 200 Nt(20, 60, 100, 120, 150 and 200 Nt). (P<0.05) It was also observed that the scale of displacementwas less for titanium plate and screws.Key words: Fixation, mandibular angle fracture, resorbable plate and screws