Phosphate Collagen Composite Research Articles

Octacalcium phosphate collagen composite for periodontal regeneration in a canine one-wall intrabony defect.

This study aimed to evaluate the regenerative capacities of octacalcium phosphate collagen composite (OCP/Col) in one-wall intrabony defects in dogs. The background data discuss the present state of the field: No study has assessed the efficacy of OCP/Col for periodontal regeneration therapy despite the fact that OCP/Col has proved to be efficient for bone regeneration. In six beagle dogs, the mandibular left third premolars were extracted 12 weeks before the experimental surgery. Standardized bone defects (5 mm in height and 4 mm in width) were simulated on the distal surface of the second premolars and mesially on the fourth premolars. The defect was filled with either OCP/Col (experimental group) or left empty (control group). Histological and histomorphometric characteristics were compared 8 weeks after surgery. No infectious or ankylotic complications were detected at any of the tested sites. The experimental group exhibited a significantly greater volume, height, and area of newly formed bone than the control group. The former also showed a greater height of the newly formed cementum than the latter, although the results were not statistically significant. The newly formed periodontal ligaments were inserted into newly formed bone and cementum in the experimental group. OCP/Col demonstrated high efficacy for bone and periodontal tissue regeneration that can be successfully applied for one-wall intrabony defects.

Long-term clinical and radiographic evaluation after maxillary sinus floor augmentation with octacalcium phosphate-collagen composite: A retrospective case series study.

The purpose of this study was to evaluate, using clinical and radiological assessments, the stability of dental implants 5years after maxillary sinus floor augmentation with octacalcium phosphate-collagen composite (OCP/Col). Maxillary sinus floor augmentation was performed through a lateral window approach. Depending on the height of the host bone, a simultaneous approach (≥5mm) or a staged approach (less than 5mm) was employed. The primary outcome was the evaluation of clinical dental implant conditions such as infection, peri-implantitis, dental implant stability, pain, and paresthesia. Secondary outcomes were the evaluation of the augmented bone volume, change rate of augmented bone volume, vertical bone height, and marginal bone loss around dental implant fixture. The conditions of all dental implants were uneventful throughout the follow-up period. Augmented bone volume and changing rate of augmented bone volume were essentially unchanged following maturation of the OCP/Col-derived new bone. The change rate of new bone volume was 21.9% in the simulated approach and 16.8% in the staged approach at 1year and 5years postoperatively. The reduction rate in vertical bone height was 7.1% in the simultaneous approach and 7.5% in the staged approach between 1year and 5years postoperatively. Mean marginal bone loss was 1.76mm with the simultaneous approach, and 0.50mm with the staged approach at 5years postoperatively. In conclusion, the success of dental implants 5years after sinus floor augmentation by OCP/Col implantation was clarified by both clinical and radiological evaluations.

A Case of Report: Bony Bridge Formation and Canine Eruption of Alveolar Cleft Closure Using Octacalcium Phosphate Collagen Composites

A Case of Report: Bony Bridge Formation and Canine Eruption of Alveolar Cleft Closure Using Octacalcium Phosphate Collagen Composites

Segmental Bone Reconstruction by Octacalcium Phosphate Collagen Composites with Teriparatide.

Octacalcium phosphate and collagen composite (OCPcol) demonstrated superior bone regeneration and has been commercialized recently in Japan. Teriparatide (TPTD) is a bioactive recombinant form of parathyroid hormone that is approved for osteoporosis treatment. Because mandibular bone reconstruction after segmental resection is a key clinical problem, it was examined whether single-dose local administration of OCPcol with TPTD can affect recovery after this procedure. OCPcol was prepared, and a commercially available hydroxyapatite and collagen composite (HAPcol) was used as a control. A 15 mm length segmental bone defect was made in the mandibular region of male beagle dogs. The experimental animals were divided in four groups. OCPcol treated with TPTD (OCPcol + TPTD), OCPcol, HAPcol treated with TPTD (HAPcol + TPTD), or HAPcol was implanted into the defect. The radiopaque areas of the implanted site were measured and statistically analyzed, and histological examination was performed after 6 months. The value of radiopaque area in total region of OCPcol + TPTD was highest (90.8 ± 7.3 mm2), followed in order by OCPcol (49.3 ± 21.8 mm2), HAPcol + TPTD (10.6 ± 2.3 mm2), and HAPcol (6.4 ± 2.3 mm2), and that of OCPcol + TPTD was significantly higher than that of HAPcol + TPTD or HAPcol. All segmented mandibles of OCPcol + TPTD and a part of those of OCPcol were bridged with newly formed bone, whereas no bone bridges were observed in HAPcol + TPTD or HAPcol. These results suggested that OCPcol treated with TPTD enabled bone reconstruction after segmental mandibular resection more than other three groups.Impact statementOctacalcium phosphate and collagen composite (OCPcol) is a bone regenerative material that has been recently commercialized in Japan. Teriparatide (TPTD) is a recombinant form of parathyroid hormone, and is used for the treatment of osteoporosis. It was investigated whether single-dose local administration of OCPcol with TPTD can repair a canine segmental bone defect, which was supposed to be an intractable bone defect. Compared with OCPcol, hydroxyapatite, and collagen composite (HAPcol) with TPTD, or HAPcol, because OCPcol with TPTD quickly enhanced bone regeneration and bridged the defect, it would be a candidate for the repair of intractable bone defect.

Octacalcium phosphate collagen composite (OCP/Col) enhance bone regeneration in a rat model of skull defect with dural defect

Cranial bone defects are a major issue in the field of neurosurgery, and improper management of such defects can cause cosmetic issues as well as more serious infections and inflammation. Several strategies exist to manage these defects clinically, but most rely on synthetic materials that are prone to complications; thus, a bone regenerative approach would be superior. We tested a material (octacalcium phosphate collagen composite [OCP/Col]) that is known to enhance bone regeneration in a skull defect model in rats. Using a critical-sized rat skull defect model, OCP/Col was implanted in rats with an intact dura or with a partial defect of the dura. The results were compared with those in a no-treatment group over the course of 12 weeks using computed tomographic and histological analysis. OCP/Col enhanced bone regeneration, regardless of whether there was a defect of the dura. OCP/Col can be used to treat skull defects, even when the dura is injured or removed surgically, via bone regeneration with enhanced resorption of OCP/Col, thus limiting the risk of infection greatly.

Octacalcium phosphate collagen composite stimulates the expression and activity of osteogenic factors to promote bone regeneration.

SummaryObjectiveThis study investigated the bone regenerative properties of an octacalcium phosphate collagen composite (OCP/Col) in a rat calvarial bone defect model.DesignAn OCP/Col or β‐tricalcium phosphate (β‐TCP)/Col disk was implanted into the critical‐sized calvarial defects and fixed 2 or 4 weeks later. The radiopacity of defects was examined after disk implantation by the radiographic examination and micro‐computed tomography (μ‐CT). Immunohistochemical and histochemical analyses were carried out to assess the bone matrix maturation, neovascularization, and osteoclast and osteoblast distribution in the neonatal bone.ResultsRadiographic and μ‐CT examination of the area of implanted OCP/Col indicated the newly formed bone and no difference from those of the original bone. Osteopontin, osteocalcin, Runt‐related transcription factor 2, type 1 collagen, vascular endothelial growth factor, and alkaline phosphatase or tartrate‐resistant acid phosphatase in the newly formed calvarial bone and the surrounding connective tissue were detected by immunohistochemistry and histochemistry. Biomarker expression was not significantly elevated at the defect site; the area of which was calculated by dividing the distance from the healthy bone margin or calvarium and dura mater surface. There was no difference in the expression of these biomarkers in the OCP/Col group at 2 and 4 weeks after surgery. In addition, the expression levels of all markers were higher in the OCP/Col group than in the β‐TCP/Col group at 2 and 4 weeks after surgery.ConclusionsThe OCP/Col as a bone regeneration material not only exhibits osteoconductive activity that is dependent on residual healthy bone tissue, but also has osteoinductive capacity, which promotes angiogenesis and osteogenic cell invasion from host tissue into the bone defect.

Clinical and experimental Study to evaluate the effect of Biphasic calcium phosphate collagen composite (cpcc) on healing of bone defects after oral surgical procedures

Background: A recent discoveries used for reconstruction in maxillofacial surgery is the composite bone graft materials. The availability of collagen I matrix make our choice to use this material in surgery .It is biomaterials that its structure could be modified by simple techniques. Studies to find a new materials use for bone reconstruction is to overcome the disadvantages of autogenous bone and the synthetic resorbable bone substitutes.
 Objectives: This study was done to evaluate the effect of biphasic calcium phosphate collagen composite (ccpc) on healing of bone defects after oral surgical procedures.
 Type of the study: A cross sectional study.
 Method: It involved 60 patients, 35 male and 25 female, age (15-40) yearsand experimental animals study involved sixty rabbits.The study was done in Department of Maxillofacial surgery in Al anbarCollege of Dentistry (2015-2016).These patients were received tooth extraction, and other minor surgical procedures .Clinical and radiographical examination and patients consents are done before surgery. The surgery was done under local anesthesia.The resulting bone cavities are filled with composite bone graft material composed from combination of lyophilized hydrolysed collagen sponge (Hemospon),Brasil and Osteon II bone graft material,Korea .The area is closed with 3/0 block silk suture .Antibiotic cover (Ampicillin 500mg ×4) for 1 week was prescribed. The patients were followed up by careful clinical examination with radiograph 15-30 days after surgery. .Sixty New Zeleandi White rabbit were used in our study for histopathologicalexamination.Intraperitoneal injection of ketamine 10 mg with XYL-M2 solution 20 mg xylazine base used to anesthetize the animals. (5mm diameter) bone defects were made using straight surgical hand piece and bur in anterior mandibular region and filled with each material. The study design involve the following groups: group 1( involve 15 rabbit; the defect was made and filled with blood clot only (control group),group 2( involve 15 rabbit, the defect was made and filled with collagen sponge only),group 3(Involve 15 rabbit, the defect was made and filled with Osteon II bone graft only),group4( involve 15 rabbit, the defect was made and filled with Osteon II bone graft +collagen (Composite bone graft).The flap were closed 3/0 black silk suture. The rabbits were killed after 30 days. 10 cmexcisional biopsy specimen was taken from the paramandibular area and placed in 10%formalin then send histopathologicalexamination.
 Results: Clinically, the treated area show good healing with absence of infection .Radiographs during follow up period show radiopacity indicating new bone formation .The results of experimental animals (Rabbits) indicategrowth new bone . In group 1 and group2, the center of the defects was depressed by surrounding tissues Eung et al, While, in group 3&group 4, the graft materials maintained the space and the center of the defect did not depress. Statistical analysis indicates that during 4 th week ,the highest healing % is (100%) in group 3 &group4 in compared to control group (50%)..A significant difference in healing % was found among the treated groups.
 Conclusion:The result indicates that biphasic calcium phosphate collagen composite can be efficiently utilized clinically.

Implantation of octacalcium phosphate collagen composites (OCP/Col) after extraction of canine deciduous teeth achieved undisturbed permanent tooth eruption

ObjectiveComposite of synthetic octacalcium phosphate and collagen (OCP/Col) enhances bone regeneration if implanted into human, canine, or rodent bone defects. This study was designed to investigate the influence on eruption of the permanent successor tooth and alveolar height of OCP/Col implantation into extraction cavities of deciduous teeth. DesignDisks of OCP/Col prepared from synthetic granules of octacalcium phosphate (OCP) and porcine atelocollagen, and commercially available sintered porous β-tricalcium phosphate (β-TCP) was implanted into the prepared defect of eleven male beagle dogs by extraction of two deciduous premolars. Untreated group had nothing implanted into the prepared defect, and physiological group (Physiol group) was observed without any treatment. Periodical macroscopic and radiographic examinations were performed until the period equivalent to the physiological eruption of permanent successor teeth (P3 and P4). ResultsAlthough no unerupted permanent successor teeth were observed among the OCP/Col, Untreated, and Physiol groups, two permanent successor teeth were unerupted in the β-TCP group. No significant difference of the alveolar heights or the eruptive position in P3 and P4 was observed between OCP/Col and Physiol groups. ConclusionOCP/Col implantation in the alveolar region that included the unerupted permanent successor teeth would cause no disturbance of permanent tooth eruption and preserve the alveolar ridge.

Clinical safety and efficacy of implantation of octacalcium phosphate collagen composites in tooth extraction sockets and cyst holes

It was demonstrated that octacalcium phosphate collagen composite achieved notable bone regeneration in bone defects in preclinical studies. On the basis of the research results, an investigator-initiated exploratory clinical trial was conducted after approval from a local Institutional Review Board. This clinical study was performed as a single-arm non-randomized intervention study. Octacalcium phosphate collagen composite was implanted into a total of 10 cases of alveolar bone defects after tooth extractions and cystectomy. Safety assessment was performed in terms of the clinical course and several consecutive laboratory examinations, and sequential radiographs were used for efficacy assessment. All participants uneventfully completed the clinical trial without major problems in their general condition. Postoperative wound swelling was observed, as also commonly seen in tooth extraction or cystectomy. Although no serious liver dysfunction, renal dysfunction, electrolyte imbalance, or abnormal urinalysis results were recognized, the number of white blood cells and C-reactive protein level temporarily increased after the operation. An increase in radiopacity in the octacalcium phosphate collagen composite–implanted site was observed in all cases. Finally, the border between the original bone and the octacalcium phosphate collagen composite–implanted site became indistinguishable. These results suggest that octacalcium phosphate collagen composite could be utilized safely in clinical situations in the future.

Bone augmentation in sinus floor elevation by octacalcium phosphate collagen composite

Event Abstract Back to Event Bone augmentation in sinus floor elevation by octacalcium phosphate collagen composite Tadashi Kawai1*, Keiko Matsui1, Yushi Ezoe1, Yuji Tanuma1*, Hidenori Tanaka2*, Fumihiko Kajii2, 3*, Atsushi Iwai2*, Osamu Suzuki4*, Shinji Kamakura3* and Tetsu Takahashi1 1 Tohoku University, Graduate School of Dentistry, Oral and Maxillofacial Surgery, Japan 2 TOYOBO CO., LTD, Japan 3 Tohoku University Graduate School of Biomedical Engineering, Bone Regenerative Engineering, Japan 4 Tohoku University, Graduate School of Dentistry, Craniofacial Function Engineering, Japan Introduction: Synthetic octacalcium phosphate (OCP) has become recognized as a highly osteoconductive bone substitute material based on in vitro and vivo studies [1],[2]. OCP enhances osteoblastic cell differentiation in vitro in a dose-dependent manner [3]. Furthermore, the dose-dependent stimulatory capacity of OCP was confirmed in vivo implantation with collagen matrix in rat critical sized calvaria defect [4]. OCP has higher solubility than be-ta tricalcium phosphate (be-ta TCP) therefore more resorbable than be-ta TCP in vivo [5]. It has been shown that OCP combined with collagen (OCP/Collagen) facilitates bone regeneration in comparison with OCP itself [6]. The osteoconductivity of OCP/Collagen has been demonstrated also in critical-sized bone defect of dog [7]. After that, we examined the effect of OCP/Collagen on bone regeneration in human small bone defect and confirmed the healing at the defect[8]. In this study, we performed sinus floor elevation for bone augmentation by OCP/Collagen as a preparation for dental implant treatment in clinical patient. Experimental methods: OCP was prepared according to a method of synthesis by mixing calcium nad phosphate solution [1]. Particle size of OCP was 300 - 500 micrometer in diameter. OCP/Collagen was molded in the shape of a disc, 9 mm diameter, and 1.5 mm thick. Then OCP/Collagen was sterilized using electron beam irradiation at 15kGy. The protocol of the clinical trial was submitted and approved by the research ethics commitee of the Tohoku University Graduate School of Dentistry. In this study, we performed sinus floor elevation in a 41-years old man at left sinus under local anesthesia. 19 OCP/Collagen discs (approximately 1.8 cc) were used in this surgery. We observed the healing at operative region and confirmed having infection or allergy, or not and radiographic examination or CT scan was performed at 3 or 6 months after operation. Furthermore, we performed bone biopsy at the same time of placement of dental implant and we examined the newly formed bone histologically. Result: There was no abnormality for healing, no infection and no allergic reaction for the entire period. OCP or OCP/Collagen does not have radiopacity under normal X-ray condition. However, radiopacity of OCP/Collagen implanted in sinus increased with time. CT scan showed radiopacity at 3 months after implantation. At 6 months, the radiopacity of that was almost same as surrounding bone of that in cancellous bone. Histological analysis showed the normal bone tissue including a little remaining impants. Discussion: These results showed that OCP/Collagen could convert to bone tissue in clinical use of sinus floor elevation. It was suggested that OCP/Collagen could be a suitable material for bone augmentation.

Comparative evaluation of biphasic calcium phosphate and biphasic calcium phosphate collagen composite on osteoconductive potency in rabbit calvarial defect.

BackgroundThe aim of this study was to determine the osteoconductivity of biphasic calcium phosphate collagen composite (BCPC) in rabbit calvarial defect model by comparing with biphasic calcium phosphate (BCP). Four 8 mm diameter bicortical calvarial defects were made in ten rabbits. Each of the defects was randomly assigned and filled with 1) collagen sponge, 2) BCP, 3) BCPC, and 4) nothing as control. The animals were sacrificed at either 2 weeks (n = 5) or 8 weeks (n = 5) healing period.ResultsAll groups showed wedge shaped new bone formation limited to the area of the defect margin at both healing periods. The amounts of new bone and defect closure were similar among all groups. In the control and collagen sponge group, the center of the defect was depressed by surrounding tissues. In contrast, in BCP and BCPC group, the center of the defect did not depressed and the grafted materials maintained the space. And the augmented area was significantly higher in BCP and BCPC group compared to the control and collagen sponge group at both healing periods (p < 0.05).ConclusionsThe BCPC and BCP demonstrated proper space maintaining capacity and osteoconductive property, suggesting BCPC can be efficiently utilized in various clinical situations.

The Regenerated Bone Quality by Implantation of Octacalcium Phosphate Collagen Composites in a Canine Alveolar Cleft Model

Synthetic octacalcium phosphate and porcine atelocollagen composites significantly enhanced bone regeneration more than β-tricalcium phosphate collagen composite and hydroxyapatite collagen composite in a rat cranial defect model. However, the long-term stability and quality of octacalcium phosphate collagen (OCP/Col) composites-derived regenerated bone, when implanted in a canine alveolar cleft model, have yet to be elucidated. The present study investigated the longterm stability and quality of bone regenerated by OCP/Col. Disks of OCP/Col or collagen were implanted in a canine alveolar-cleft model (n = 6). Then, bone regeneration in the implanted areas was investigated macroscopically, radiographically, and histologically at 10 months after implantation. In addition, three-dimensional quantitative images of regenerated bone were analyzed by microcomputed tomography. Macroscopically, the OCP/Col treated alveolus was clearly augmented, and radio-opacity in the OCP/Col implanted area was comparable to that of the original alveolus bone. On histological analysis, the area was mostly filled with newly formed bone, and a few granules of implanted OCP/Col were enclosed in it. In the microcomputed tomography analysis, the regenerated bone volume in the OCP/Col group was larger than that in the collagen group. OCP/Col-derived bone consisted of outer cortical and inner cancellous structure with dense trabeculae and seemed like the original bone structure. OCP/Co composites could be a useful bone regenerative material to substitute for autogenous bone because their implantation could elicit high bone regeneration and active structural reconstitution.

Bone regeneration by octacalcium phosphate collagen composites in a dog alveolar cleft model

Octacalcium phosphate (OCP) and porcine atelocollagen sponge composites (OCP/Col) markedly enhanced bone regeneration in a rat cranial defect model. To assess clinical application, the authors examined whether OCP/Col would enhance bone regeneration in an alveolar cleft model in an adult dog, which was assumed to reflect patients with alveolar cleft. Disks of OCP/Col or collagen were implanted into the defect and bone regeneration by OCP/Col or collagen was investigated 4 months after implantation. Macroscopically, the OCP/Col-treated alveolus was obviously augmented and occupied by radio-opacity, and the border between the original bone and the defect was indistinguishable. Histological analysis revealed it was filled and bridged with newly formed bone; a small quantity of the remaining implanted OCP was observed. X-ray diffraction patterns of the area of implanted OCP/Col indicated no difference from those of dog bone. In the collagen-treated alveolus, the hollowed alveolus was mainly filled with fibrous connective tissue, and a small amount of new bone was observed at the defect margin. These results suggest that bone was obviously repaired when OCP/Col was implanted into the alveolar cleft model in a dog, and OCP/Col would be a significant bone regenerative material to substitute for autogeneous bone.

Octacalcium phosphate (OCP) collagen composites enhance bone healing in a dog tooth extraction socket model

The authors have reported that a scaffold constructed of synthetic octacalcium phosphate (OCP) and porcine atelocollagen sponge (OCP/Col) enhanced bone regeneration more than sintered beta-tricalcium phosphate collagen composite or sintered hydroxyapatite collagen composite with a rat calvarial defect model. To aim for clinical application, the present study investigated whether OCP/Col would enhance bone healing in a dog tooth extraction socket model. Six adult, male, beagle dogs were used. The tooth extraction socket model was made by extracting bilateral third maxillary incisors and the subsequent removal of buccal bone. Disks of OCP/Col were implanted into one side of the model and the other side was untreated. The specimens were fixed 1 or 3 months after implantation. In radiographic analysis, the OCP/Col-treated group showed a wider range of radiopacity than the untreated control. Histologically, the OCP/Col-treated group showed more abundant newly formed bone than untreated control, and the implanted OCP was gradually resorbed. In morphometrical analysis, enlargement of the buccal alveolus in the OCP/Col group was significantly greater than in the untreated control. This study showed that implanted OCP/Col would be replaced by newly formed bone and OCP/Col implantation would enhance bone healing in a tooth socket model.

Dehydrothermal treatment of collagen influences on bone regeneration by octacalcium phosphate (OCP) collagen composites

We have engineered a scaffold constructed of synthetic octacalcium phosphate (OCP) and collagen composites (OCP-collagen) and report that OCP-collagen significantly enhanced bone regeneration more than the implantation of OCP. We hypothesized that the dehydrothermal treatment (DHT) during the fabrication of OCP-collagen might influence bone regeneration by OCP-collagen. To examine this hypothesis, bone regeneration by the implantation of OCP-collagen with DHT [OCP/Col(+)] was compared with that by OCP-collagen without DHT [OCP/Col(-)]. It was confirmed that both OCP/Col(+) and OCP/Col(-) contained the characteristics of OCP structure in X-ray diffraction. Before implantation, calcium deposition derived from OCP was observed within the collagen of both OCP/Col(+) and OCP/Col(-) by undecalcified histological sections. OCP/Col(+) or OCP/Col(-) was implanted into the critical-sized defects in rat crania. Radiographic and histological examination was performed and the percentage of newly formed bone (n-Bone%) in the defect was determined by a histomorphometrical analysis. N-Bone% treated with OCP/Col(+) was significantly higher than that with OCP/Col(-) at 4 and 12 weeks after implantation, because fast degradation of the implanted collagen of OCP/Col(-) elicited disappearance of the scaffold for bone regeneration. The stiffness of the calcified collagen in OCP-collagen would be more important than the existence of calcified collagen to enhance the bone regeneration by OCP-collagen composites. The present study suggests that the dehydrothermal treatment would influence effective bone regeneration by OCP-collagen.

Differences of Bone Regeneration by Various Calcium Phosphate/Collagen Composites

Our previous studies showed that synthetic octacalcium phosphate (OCP) enhances bone regeneration more than hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP). Also, a synthetic bone substitute constructed of synthetic octacalcium phosphate (OCP) and porcine atelocollagen sponge (OCP/Col) showed stable bone regeneration. The present study was designed to investigate the difference of bone regeneration by OCP/Col and other calcium phosphate-collagen composites. OCP/Col, β-TCP$-collagen% composite (β-TCP/Col), or HA$-collagen% composite (HA/Col) sponge was prepared from pepsin-digested atelocollagen isolated from the porcine dermis and OCP, β-TCP, or HA granules, respectively. A standardized critical-sized defect was made in the rat calvarium, and various calcium phosphate-collagen composites were implanted into the defect. The rats were fixed at four weeks after implantation and radiographic and histological examinations were performed by undecalcified cross sections of implants. Radiographic examination showed that uniform radiopaque masses were observed in the created defects treated with OCP/Col, whereas granulous and foggy radiopacity was observed in β-TCP/Col and HA/Col. Histological examination showed that newly formed bone was observed in the reticulum of OCP/Col and around the implanted OCP. The regenerated bone by β-TCP/Col or HA/Col seemed to be less than that by OCP/Col and would not to be nucleated by the granules of β-TCP or HA. The present study indicated that bone regeneration by OCP/Col was different from those of β-TCP/Col and HA/Col. Application of OCP/Col would be expected for clinical use in the future.

Development of a Resorbable Tricalcium Phosphate (TCP) Amine Antibiotic Composite

AbstractCalcium phosphate collagen composites are currently being used to rebuild bone. Commercial collagen preparations have been claimed to he hvpo-antigenic but none are non-antigenic. The collagen in calcium phosphate collagen composites is eventually degraded to its component amino acids. Two thirds of collagen consists of glvcine, hvdroxvproline, and proline. Since both tricalcium phosphate (TCP) and collagen are resorbable and both can he utilized to form bone, incorporation of amino acids into TCP-amino acid composites should nrovide the building blocks for formation of new bone. Stich composites should also be non-antigenic. Previous work conducted with composites of amino acids with aluminum calcium phosphorous oxide (ALCAP) ceramics, has shown that these composites can be uised to repair traumatized bone in rats. In our study, experiments conducted with TCP cysteine, Ivsine, or proline composites showed that the composites, after setting to hardness, degrade slowly and can he molded into different froms. Dissolution studies were conducted with composites of TCP with each of the above amino acids in Tris-MCl buffer (PH 7.4) at 37°C in vitro. Experiments conducted with antibiotics showed that antibiotics such as penicillin and ervthromvcin can be incorporated into the TCP amino acid composite. Subcutaneous implants of TCP amino acid composites in rats showed that most of the TCP-proline composite was degraded bv day 4, TCP-lvsine composite he day 7, and TCP-cysteine composite by day 21. Our results suggest that TCP amino acid composites are biocomnatible and can he used to repair experimentally traumatized bone.