Papers by Author: Guy Daculsi

Abstract: Due to the lack of macroporosity in current available Calcium Phosphate cement used in osteoarticular surgery, Micro and Macroporous Biphasic CaP Cement (MCPC™) was developed. The MCPC™ concept was the association of a settable and a fast resorbable matrix and a sieved fraction of microporous biphasic calcium phosphate (BCP) granules, recognized for the high osteoconductive and osteogenic properties. During the resorption of the matrix, a porous structure is created and the osteoconductive effect of the granules promotes the bone ingrowth. A goat preclinical study was realized to evaluate the efficacy of MCPC™ for C3 and C4 vertebral body filling defects during 6 months. Bone remodelling was evidenced demonstrating bone ingrowth at the expense of the cement and surrounding the residual BCP granules. Bone trabeculae were observed coming from the spongious bone to the implant site. Human vertebral body filling cases demonstrated the biocompatibility and the safety of MCPC™ for bone reconstruction. Results of this study demonstrated the importance of special combination of calcium phosphate granules in the MCPC™ to provide macroporosity and scaffolding for newly formed bone.

Abstract: An hydrated putty was prepared by mixing submicron particles, rounded particles and granules of Biphasic Calcium Phosphate (BCP) ceramics composed of HA and β-TCP phases. The material filled entirely critical sized defects in the femoral epiphysis of NZW rabbits. After 3, 6 and 12 weeks, histology revealed that submicron particles were rapidly degraded by multinucleated TRAP-positive cells. This osteoclastic resorption stimulated bone ingrowth while the large BCP particles served as scaffold supporting bone healing by osteoconduction.

Abstract: Current resorbable membranes are generally from animal origin, like collagen, and are largely used in dentistry or orthopaedic for TGR (Tissue Guided Regeneration), in neurosurgery for Dura matter healing and others. Calcium alginates are generally used for wound dressing (external uses). The purpose of this study was to evaluate the osteogenic property of meshes realized with calcium alginate fibers. Membrane meshes were implanted in critical size defect of rabbit femoral epiphysis during 3 and 6 weeks. Micro CT and histological analysis demonstrated biocompatibility of calcium alginate meshes in bony area. Calcium alginate meshes have no osteogenic and osteoconductive properties, however calcium alginate meshes could be a good candidate for replacement of dacron balloon used in vertebroplasty.

Abstract: We have developed a new injectable bone substitute combining specific granules of BCP with or without radiopaque elements with a reversible thermo sensitive resorbable carrier such as Pluronic F-127. The composite is liquid at ambient temperature and set as hydrogel at 37°C. Rabbit experiment demonstrates high biocompatibility and bone ingrowth at the expense of the injectable bioceramic composite.

Abstract: The aim of this study was to evaluate the capacity of the association of calcium phosphate cement with collagen membrane for large segmental bone defect. Six adult beagle dog underwent defect creation in the ulna and was reconstructed with combination of macroporous calcium phosphate cement MCPC® and resorbable collagen membrane EZ Cure®. After 6 months of implantation, the samples were analyzed with Micro CT, light microscopy and SEM using BSE. Bridging of the defect with a lamellar and well organized bone was achieved in all animals. MCPC granules resorption was increased at the extremities of the implant. Collagen membrane at the expense of the implant was replaced by periosteum-like formation. The results demonstrate the ability of the composite to reconstruct large segmental and critical size defect in long bone.

Abstract: We have developed a novel macroporous calcium phosphate cement MCPC® that sets to poorly crystalline apatite after mixing the powder component with an aqueous solution and has interconnective macroporosity We performed cranioplasty on rat model by injecting the new macroporous calcium phosphate cement MCPC®. The mechanical property of the cement is about 12MPa after 24 hours (compression test). The cement matrix is totally transformed into poorly crystalline apatite in 48 hours. This study demonstrates that MCPC® cement was suitable and efficient for parietal bone reconstruction. Its injectability and moldability allows to be used in bone reconstruction surgery and its mechanical properties are compatible to support calvarial reconstruction. In addition, a bone ingrowth onto the BCP granules occurred on time.

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.

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: 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: 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.