Cortical bone resorption of fibular bone after maxillary reconstruction with a vascularized fibula free flap: a computed tomography imaging study

This study was performed to evaluate the cortical bone resorption of fibular bone after maxillary reconstruction with a fibula free flap. A total of 35 patients with maxillary defects that were repaired using a fibula flap (62 fibula segments) between January 2011 and January 2016 were enrolled. Computed tomography (CT) images taken 1 week and 1 year postoperative were used to evaluate cortical bone resorption. The 62 fibula segments were measured on four different surfaces in the CT images. At 1 week, the thickness of the cortical bone was 2.57 ± 0.58 mm, 2.72 ± 0.46 mm, 3.84 ± 0.98 mm, and 4.36 ± 0.90 mm for the exterior, interior, superior, and inferior sides, respectively. At approximately 1 year, the cortical bone thickness was significantly reduced to 2.00 ± 0.65 mm (P < 0.01), 2.25 ± 0.60 mm (P < 0.01), 3.37 ± 0.90 mm (P < 0.01), and 2.96 ± 0.84 mm (P < 0.01) for the exterior, interior, superior, and inferior sides, respectively. The cortical bone thickness of fibular bone is significantly reduced 1 year after the restoration of maxillary defects with a fibula free flap, most significantly on the inferior side.     

Influence of object translucency on the scanning accuracy of a powder-free intraoral scanner: A laboratory study

Statement of problem

Limited information is available regarding the influence of object translucency on the scanning accuracy of a powder-free intraoral scanner.

Are antithrombotic agents necessary for head and neck microvascular surgery?

The aim of this prospective study was to determine the effect of antithrombotic agents in preventing thrombosis after head and neck reconstructive surgery. A randomized clinical trial of referred patients undergoing free flap surgery between February 2015 and July 2017 was conducted. Four hundred and fifty-four patients were randomly assigned to group A (n = 153), administered aspirin and low molecular weight dextran; group B (n = 150), administered low molecular weight heparin; and group C (n = 151), not administered any antithrombotic agent. Patient demographic characteristics, donor site, thrombosis, haematoma, and flap failure were recorded. Coagulation values including platelet count, prothrombin time, and activated partial thromboplastin time were measured during the perioperative period. Repeated-measures ANOVA and the χ² test were used for data comparisons. No significant inter-group differences were observed for postoperative microvascular thrombosis (P = 0.536) or flap failure (P = 0.615) among the three groups. There were more postoperative haematoma revisions in group B than in groups A and C (P = 0.032). It is concluded that postoperative antithrombotic agents neither provide a significant improvement in the free flap success rate nor decrease the risk of thrombosis and may increase the risk of haematoma.     

Effect of two heat treatments on mechanical properties of selective-laser-melted Co-Cr metal-ceramic alloys for application in thin removable partial dentures

Statement of problem

Heat treatment has been used to reduce the residual stress of alloys fabricated by selective laser melting (SLM) to avoid deformation. Co-Cr metal-ceramic alloys are used to fabricate metal-ceramic restorations and removable partial dentures (RPDs) on the same substrate by SLM. A heat treatment that enables the fabrication of metal-ceramic restorations and RPDs with excellent mechanical properties should be evaluated.

An implant impression technique involving abutment transition from interim prostheses to definitive restorations in the esthetic zone

This article presents an impression technique involving transfer of the position of implants and the emergence profile of splinted interim prostheses fabricated on nonindexed interim abutments to definitive single crowns fabricated on indexed abutments.     

Passively fitting implant-supported complete-arch interim restoration

This article presents a technique for fabricating a passively fitting implant-supported screw-retained complete-arch interim restoration with resistance to early fracture. Two gypsum casts were obtained from an implant impression using the splinting technique. The complete-arch interim restoration with abutment access holes, which was reinforced with a glass fiber splint, was fabricated on one cast and connected to restorative abutments on the other cast extraorally to eliminate stresses from the polymerization shrinkage of resin.