Change in CT Value at Mandibular Ramus After Mandibular Setback and Advancement Surgery With Bicortical Absorbable Plate Fixation

Abstract

Purpose: This study aimed to evaluate changes in computed tomography (CT) value of ramus bone after sagittal split ramus osteotomy (SSRO) in class II and class III patients using absorbable plates and screws. Patients and Methods: In the retrospective study, the participants were female patients with jaw deformities who underwent bilateral SSRO with Le Fort I osteotomy. Maximum CT values (pixel values) of lateral and medial cortexes at anterior and posterior sites of the ramus were measured preoperatively and 1 year postoperatively by using horizontal planes at the mandibular foramen level (upper level) and 10 mm under the mandibular foramen level (lower level) parallel to Frankfurt horizontal plane. Results: Fifty-seven patients and 114 sides (28 class II: 56 sides and 29 class III: 58 sides) were evaluated. Although CT values decreased at most sites of the ramus cortical bone after 1 year of surgery, they increased at the posterior-medial site at the upper level in class II (P=0.0012) and the lower level in class III (P=0.0346). Conclusion: This study suggested that bone quality at the mandibular ramus could change after 1 year of surgery, and there could be differences between mandibular advancement and setback surgery.

Advances and Prospects in Materials for Craniofacial Bone Reconstruction

“…), alloys, as well as the more commonly used titanium mesh (TM) and the composites therein have been applied to clinical practice. − Besides, in recent years more advanced resorbable materials with sufficient strength and moderate degradation rate have emerged, which is especially meaningful in the craniofacial bone repair species of pediatric and adolescent patients, considering the development of craniofacial bone in growing children. The main absorbable materials currently used in craniomaxillofacial surgery are aliphatic polyesters, such as RapidSorb (PLLA), Polymax (P­(L/DL) LA), etc. − Fewer resorbable products with osteoconductive activity, such as PLLA-μHA complexes (FIXSORB MX), are available. − In recent years, modifications of titanium mesh, , biodegradable alloys such as magnesium alloys, , addition of coatings with antimicrobial or biocompatible properties on the surface of the alloy, materials that can deform with children’s bone development, , and other patented designs try to make up for the shortcomings of the existing materials on the market, and resorbable composites that combine the advantages of a variety of materials themselves have become a current research hotspot and a trend in the development of bone repair materials.…”