Microcomputed tomography cortical bone evaluation for craniofacial implantology

Introduction/Objective. Good implant stability is one of the most important factors for successful implant therapy. This precondition is important to all kind of implants, oral and extra-oral (EO) ie. Craniofacial implants as well. One of the most important factors for satisfactory implant stability is the bone quality, particularly of the cortical bone, which is determined by its microarchitectural parameters. The aim of this paper was to assess cortical bone microarchitectural parameters in the targeted regions for craniofacial implant placement. Methods. Bone quality on targeted localisations was determined by Micro CT method on cadaver model. The target places for implant placement were: periorbital, perinasal and periauricular region. Microarchitectural parameters included cortical thickness (Ct.Th), cortical porosity (Ct.Po), pore diameter (Po.Dm) and pore separation (Po.Sp). Results. The smallest cortical porosity, (Ct.Po. 4.1 %) and the largest pore separation (Po.Sp. 0.5 mm), were determined in glabella. The maximum cortical thickness was found in the zygomatic region (Ct.Th. 2.7 mm) as well as pore diameter (Po.Dm. 0.2 mm). The mastoid part of the temporal bone showed the smallest cortical thickness (Ct.Th.1.2 mm) and pore separation (Po.Sp. 0.3 mm). Highest cortical porosity was in the perinasal region (Ct.Po. 8.5%). Conclusion. The bone quality measured through microarchitectural parameters was good in all the regions of interest for the disk and screw shape EO implant anchorage.

Self Formation of Porous Silicon Structure: Primary Microscopic Mechanism of Pore Separation

A microscopic mechanism of the self-formation of a dense pore system in the porous silicon is proposed. According to it, the process of porous silicon self-formation is dictated by the laws of dynamics for a charge carriers system. The proposed mechanism is proved by the results of computer simulation. The values of inter-pore separation distance in p-type based porous material and anodization current threshold density are evaluated; the dependence of an inter-pore separation distance on the carriers concentration, close to n-1/2, is predicted.