Key Engineering Materials Vols. 361-363

Abstract: The association of TricOsTM (Macroporous Biphasic Ceramic Phosphate MBCP granules) and the fibrin sealant FS VH S/D 4, has been developed to answer a challenging request of orthopaedic surgeons: a biocompatible, osteogenic, mouldable, and self-hardening bone substitute able to fill randomly shaped bone defects. The aims of this study was the evaluation of the performance and safety of the bioactive bone substitute TricOs™ associated with a fibrin sealant in regeneration of functional bone. The pre-clinical tests were conducted to optimize MBCP granules size and ratio MBCP–FS VH S/D 4 (sheep maxillary sinus grafting, femoral epiphysis defect in rabbits, long bone defects in sheep). A clinical study design was set up as an exploratory prospective French multicentric phase II study sponsored by INSERM (Institut National de la Santé et de la Recherche Médicale). The application was the TOV (Tibial Osteotomy of Valgisation) using osteosynthesis and bone substitute: TricOs™ mixed with the fibrin sealant (FS VH S/D 4) for filling the space created. The follow up is 13 months with safety checks, clinical assessments, highsensitivity X-ray, and CT-scan imaging. A bone sample will be collected from the reconstructed area at 12 months, during the osteosynthesis material removal surgery. The principal criterion is CT-scan imaging performed 12 months after TOV surgery, before material removal, to assess qualitative and quantitative bone reconstruction. Animals’ studies demonstrate that the biomaterial is safe to use and shows osteoconductive properties, granules resorption and bone ingrowth at the expenses of the implants. As for clinical trial, 7 patients are today included in the study: This paper present the first results obtained from X-ray imaging during follow up.

Abstract: To overcome autograft use for dental implantation, it is important to prevent bone loss after tooth extraction or to restore alveolar bone level after pathological diseases. Biphasic calcium phosphate (BCP), mixture of HA and ß-TCP, have proven its performance in orthopaedic, while few studies have been reported in dentistry. We reported 5 years clinical follow up on bone regeneration after immediate dental root filling. MBCP 60/40 and MBCP 20/80 are biphasic CaP intimate mixture of HA/TCP 60/40 and 20/80; with interconnected macroporosity and microporosity. Forty cases have been distributed in two groups for alveolar pocket filling. Seven cases without filling are used as control. X-Ray at 0, 3, 6, 12 months and 5 years follow up for some patients were performed. In all the 40 cases, radio-opacity of the implantation area decreases on time, indicating resorption and bone ingrowths at the expense of the two bioceramics. No difference in the resorption kinetics appeared on X-Ray. After 1 year, the implantation area looks as physiological bone and is maintained on time. The newly formed bone is preserved after 5 years contrarily to the controls cases (without filling)where we observed decrease of 2 to 5 mm. This study demonstrated that immediate filling of alveolar pocket after tooth extraction is a preventive method of the jaw bone resorption. After long term (other one year) resorption and bone ingrowth were demonstrated for both micro and macroporous biphasic calcium phosphate with two different HA/TCP ratio.

Abstract: Successful craniofacial reconstruction needs both a well-known and a reliable reconstruction material. However, there is often a lack of long-term knowledge of the tissue reactions and healing process in the human body. In this study, frontal sinus obliterations with bovine bone natural hydroxyapatite derivative (BHA), synthetic bioactive glass S53P4 (BAG) and hydroxyapatite cement (HAC) were investigated with clinical, histologic, scanning electron microscopic (SEM) and energy dispersive x-ray analysis (EDXA) 27, 12 and 3 years postoperatively. The aim was to determine the long-term clinical biocompatibility of the used materials. Histologic studies revealed bone formation with BHA particles and lamellar bone with BAG granule remnants in close contact to the new bone formation. In HAC reconstruction there was scattered fibroconnective tissue growth without new bone formation in the surface of HAC implantation. Neither foreign body reaction nor any abnormal findings were seen. SEM studies revealed a CaP layer on the surface of BAG granule remnants. In EDXA studies, composition profiles showed Ca-, P- and Si- rich layers on the BAG granule surface. No differences were found in CaO and P2O5 levels between BHA granules and HAC implantation and the surrounding bone. All investigated biomaterials were well tolerated in long-term applications.

Abstract: The development of implantology requires enough bone support, sufficient bone architecture. The use of autograft remains the gold standard; however the surgeons use cortical bone coming from mandibular part or craniofacial site, involving severe anaesthetic bone loss. The strategy of bone substitutes in place of autograft can be an efficient method. Several patients having a sinus lift augmentation using MBCP, and BioOss have been performed in human, and bone biopsies were realized during the preparation of the site for dental implantation. Biopsies were analyzed in classical histology without decalcification and by 3D reconstruction using micro CT. Both techniques revealed bone ingrowth and MBCP resorption. For BioOss, no bone ingrtowth and resorption process were observed in spite of stability of the implant and clinical efficiency. These case reports confirm the performance of bone substitutes for Sinus Lift augmentation.

Abstract: Surface roughness modulates the osseointegration of orthopaedic and dental titanium implants. High surface roughness is currently obtained by blasting of titanium implants with silica or aluminium abrasive particles. This process includes into the surface abrasive particles and may cause the release of cytotoxic silica or aluminium ions in the peri implant tissue. To overcome this drawback, we currently develop an innovative gridblasting process using Biphasic Calcium Phosphate (BCP) particles (RBBM Resorbable and Biocompatible Blast Media) to generate biocompatible roughened titanium surface. This work present the technique of blasting using RBBM particles to provide a roughened surface which does not release cytotoxic elements and (ii) to assess the effects of such a roughened surface for bone osteointegration in critical size rabbit defect. Our results demonstrate that resorbable biphasic calcium phosphate abrasive particles can be used to create titanium surface roughness. This grid blasting process increases surface roughness of titanium implants and offers a non cytotoxic surface for rapid and efficient osteointegration.