Skeletal Stability after Orthognathic Surgery with Resorbable Bone Fixation Devices Composed of Hydroxyapatite Particles and Poly-L-Lactide Acid

Abstract

The objective of this study was to assess the usefulness of a bioresorbable osteosynthesis system consisting of a hydroxyapatite and poly-L-lactide (HA/PLLA) osteosynthesis system for orthognathic surgery. The subjects were divided into five groups. Group HA/PLLA-Ti consisted of 18 patients who received Le Fort I osteotomy (L1) and bilateral sagittal split osteotomy (SSRO) with an HA/PLLA osteosynthesis system being used for maxillary fixation and a titanium osteosynthesis system being used for mandibular fixation. The HA/PLLA-HA/PLLA group consisted of 4 patients who received L1 and SSRO with an HA/PLLA osteosynthesis system being used for jaw bone fixation. The Ti-Ti group consisted of 37 patients who received L1 and SSRO with a titanium osteosynthesis system being used. A HA/PLLA osteosynthesis system was used for mandibular fixation in 11 patients in the HA/PLLA group and a titanium osteosynthesis system was used in 21 patients in the Ti group in whom SSRO was used for orthognathic surgery. Lateral cephalograms were taken before surgery, immediately after surgery, and at least six months after surgery. Changes in the positions of ANS, point A, point B and Pog were examined. Postoperative changes in the maxilla and mandible were less than 1 mm on cephalograms except for the vertical change at ANS, point B and Pog in the HA/PLLA-HA/PLLA group. There was no significant difference in postoperative skeletal stability among the groups. The tendency to relapse was greater in cases with large surgical movements of the maxilla and/or mandible.
It is concluded that an HA/PLLA osteosynthesis system is clinically useful for orthognathic surgery and maintains postoperative skeletal stability equivalent to that by titanium miniplates.