Comparison between the rigidity of bicortical screws and a miniplate for fixation of a mandibular setback after a simulated bilateral sagittal split osteotomy.
OBJECTIVE
This investigation compared the biomechanical stability of three bicortical screws with that of a single four-hole miniplate after 5-mm mandibular setback after a bilateral sagittal split osteotomy (BSSO) in cadaver mandibles.


METHODS
Thirty human cadaver hemimandibles underwent BSSO followed by two different rigid fixation techniques. All specimens had no third molar, bony pathology, or evidence of mandibular fracture, and there was no history of renal disease or hyperparathyroidism. The specimens were randomly divided into two groups. In group I, three bicortical screws were placed at the superior border, and in group II, one four-hole miniplate was secured on the external oblique ridge with four monocortical screws. The bony height of the mandible was recorded. Maximum resistance load (MRL), the greatest load recorded just before a sudden decrease in load level (bone or fixation failure), was recorded when the mandibles were tested in a compression machine. Multiple regression analysis was used to evaluate the differences in bone height and the MRL between groups I and II.


RESULTS
The mean bone height in groups I and II were 28.64 +/- 2.50 mm and 28.72 +/- 4.08 mm, respectively. The mean MRL in group I (20.49 +/- 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 height and the MRL between group I and group II (beta = 2.3492, P = .4114).


CONCLUSIONS
There was no statistically significant difference in stability provided the two techniques.
Tharanon
W
W
Dental Department, Khon Kaen Regional Hospital, Thailand.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001860:Bone Plates; D001863:Bone Screws; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D019248:Jaw Fixation Techniques; D008297:Male; D008334:Mandible / Q000601:surgery*; D008875:Middle Aged; D010027:Osteotomy; D011897:Random Allocation