Hagiwara, Yoshiyuki

Purpose: To clinically evaluate the use of ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/A) for the frameworks of removable dental prostheses (RDPs). Materials and Methods: A total of 20 Ce-TZP/A RDPs (10 complete dentures and 10 implant-supported overdentures) were used in 16 patients, and the presence/ absence of complications and patient complaints were evaluated. Results: The survival rate of the RDPs during a mean follow-up period of 55.6 months was 100%, with no major complications. Conclusion: The patients experienced uneventful courses functionally and esthetically. In addition, there was no incidence of breakage or repair related to the Ce-TZP/A frameworks.

Purpose: Ultraviolet (UV)-mediated photofunctionalization technology is intended to enhance the osseointegration capability of titanium implants. There are concerns about orthodontic anchor screws loosening under immediate loading protocols in adolescent orthodontic treatment. The purpose of this in vivo study was to evaluate the effects of photofunctionalization on the intrabony stability of orthodontic titanium anchor screws and bone-anchor screw contact under immediate loading in growing rats. Materials and Methods: Custom-made titanium anchor screws (1.4 mm in diameter and 4.0 mm in length) with or without photofunctionalization pretreatment were placed on the proximal epiphysis of the tibial bone in 6-week-old male Sprague-Dawley rats and were loaded immediately after placement. After 2 weeks of loading, the stability of the anchor screws was evaluated using a Periotest device, and the bone-anchor screw contact ratio (BSC) was assessed by a histomorphometric analysis using field-emission scanning electron microscopy. Results: In the unloaded group, Periotest values (PTVs) were ~25 for UV-untreated screws and 13 for UVtreated screws (P .01), while in the immediate-loading group, PTVs were 28 for UV-untreated screws and 16 for UV-treated screws (P .05). Significantly less screw mobility was observed in both UV-treated groups regardless of the loading protocol. The BSC was increased ~1.8 fold for UV-treated screws, compared with UV-untreated screws, regardless of the loading protocol. Conclusion: Photofunctionalization enhanced the intrabony stability of orthodontic anchor screws under immediate loading in growing rats by increasing boneanchor screw contact. Keywords: mini-implants, mini-screws, temporary anchorage devices

Purpose: The aim of this study was to evaluate whether photofunctionalization of titanium mesh enhances its osteoconductive capability. Materials and Methods: The titanium mesh (0.2 mm thickness) used in this study was made of commercially pure grade-2 titanium and had hexagonal apertures (2 mm width). Photofunctionalization was performed by treating titanium mesh with UV light for 12 minutes using a photo device immediately before use. Untreated or photofunctionalized titanium mesh was placed into rat femurs, and bone generation around titanium mesh was profiled using three-dimensional (3D) microcomputed tomography (micro-CT). A set of in vitro experiments was conducted using bone marrow-derived osteoblasts. Results: Photofunctionalized titanium mesh surfaces were characterized by the regenerated hydrophilicity and significantly reduced surface carbon. Bone generation profiling at week 3 of healing showed that the hexagonal apertures in photofunctionalized mesh were 95% filled, but they were only 57% filled in untreated mesh, particularly with the center zone remaining as a gap. Bone profiling in slices parallel to the titanium surface showed that photofunctionalized titanium mesh achieved 90% bone occupancy 0 to 400 μm from the surface, compared with only 35% for untreated mesh. Bone occupancy remained as high as 55% 800 to 1,200 μm from photofunctionalized titanium mesh surfaces, compared with less than 20% for untreated mesh. In vitro, photofunctionalized titanium mesh expedited and enhanced attachment and spread of osteoblasts, and increased ALP activity and the rate of mineralization. Conclusion: This study may provide novel and advanced metrics describing the osteoconductive property of photofunctionalized titanium mesh. Specifically, photofunctionalization not only increased the breadth, but also the 3D range, of osteoconductivity of titanium mesh, enabling space-filling and far-reaching osteoconductivity. Further translational and clinical studies are warranted to establish photofunctionalized titanium mesh as a novel clinical tool for better bone regeneration and augmentation. Keywords: bone augmentation, guided bone generation (GBR), hydrophilicity, implants, osseointegration, ultraviolet (UV) light