COMPARISON BETWEEN THE RIGIDITY OF BICORTICAL SCREWS AND A MINIPLATE FOR FIXATION OF A MANDIBULAR SETBACK AFTER A SIMULATED BILATERAL SAGITTAL SPLIT OSTEOTOMY
W. Tharanon, COMPARISON BETWEEN THE RIGIDITY OF BICORTICAL SCREWS AND A MINIPLATE FOR FIXATION OF A MANDIBULAR SETBACK AFTER A SIMULATED BILATERAL SAGITTAL SPLIT OSTEOTOMY, Journal of oral and maxillofacial surgery, 56(9), 1998, pp. 1055-1058
Purpose: This investigation compared the biomechanical stability of th
ree bicortical screws with that of a single four-hole miniplate after
5-mm mandibular setback after a bilateral sagittal split osteotomy (BS
SO) in cadaver mandibles. Materials and Methods: Thirty human cadaver
hemimandibles underwent BSSO followed by two different rigid fixation
techniques. AU specimens had no third molar, bony pathology, or eviden
ce of mandibular fracture, and there was no history of renal disease o
r hyperparathyroidism. The specimens were randomly divided into two gr
oups. In group I, three bicortical screws were placed at the superior
border, and in group II, one four-hole miniplate was secured on the ex
ternal oblique ridge with four monocortical screws. The bony height of
the mandible was recorded. Maximum resistance load (MRL), the greates
t load recorded just before a sudden decrease in load level (bone or f
ixation failure), was recorded when the mandibles were tested in a com
pression machine. Multiple regression analysis was used to evaluate th
e differences in bone height and the MRL between groups I and II. Resu
lts: The mean bone height in groups I and II were 28.64 +/- 2.50 mm an
d 28.72 +/- 4.08 mm, respectively. The mean MRL in group I (20.43 +/-
7.22 kg) was greater than in group II(17.41 +/- 7.81 kg). The multiple
regression analysis showed no significant difference in the bone heig
ht and the MRL between group I and group II (beta = 2.3492, P = .4114)
. Conclusion: There was no statistically significant difference in sta
bility provided the two techniques.