Postoperative Skeletal Stability after Bimaxillary Orthognathic Surgery in Patients with Mandibular Prognathism using Resorbable Poly (L-Lactide/D-Lactide/Glycolide) Bone Fixations Devices

Abstract

The clinical efficacy of new resorbable plate and screw fixation devices (PLDG osteosynthesis system) for jaw stabilization in bimaxillary orthognathic surgery was evaluated in this study.
PLDG plates and screws were fabricated from a unique tripolymer which was a composite of poly L-Lactide/D-Lactide/Glycolide (PLDG) with a molecular ratio of 85/5/10. It was heated by immersion in hot sterilized water until it became plastic and was then fitted to the surface of the bone.
The skeletal stability after Le Fort I osteotomy and the bilateral sagittal split ramus osteotomy was evaluated on lateral cephalograms in 46 patients with mandibular prognathism.
The subjects were divided into three groups based on the types of osteosynthesis systems used. Group TI consisted of 22 patients in whom a titanium osteosynthesis system was used for bone fixation. Group LA consisted of 14 patients in whom the PLLA osteosynthesis system was used, and group DG comprised 10 patients in whom the PLDG osteosynthesis system was used for bone fixation at the bilateral border of the piriform aperture.
Lateral cephalograms were taken before surgery, immediately after surgery, and at least six months after surgery to examine the usefulness of bioresorbable osteosynthesis system for bone fixation in orthognathic surgery.
Changes in the positions of point A, ANS, point B and menton were examined in this study.
The postoperative changes of the maxilla and mandible were less than 1 mm on cephalograms except the horizontal changes at point B in group LA and group DG.
There was no statistical difference in the postoperative skeletal stability among the three groups.
The results of this study suggest that the PLDG osteosynthesis system is clinically useful since the system fits the bone surface tightly and maintains the postoperative skeletal stability.