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Poster 28
Scientific Poster Session Materials and Methods: Biodegradable hydrogels were prepared through the glutaraldehyde cross-linking of gelatin and freeze-dried. The rabbit PRP was dropped onto the freeze-dried hydrogel, followed by leaving at room temperature to obtain the gelatin hydrogel incorporating PRP. Bone defects of 10-mm gap were made in the ulna bone of rabbits and then applied with the gelatin hydrogel incorporating PRP. Fibrin incorporating PRP and free PRP were applied to the defect as controls. Bone repairing at the defects was evaluated by histological and soft x-ray examinations or dual energy x-ray absorptometry (DEXA) to measure the bone mineral density. Results: In the histological and soft x-ray studies, bone repairing was observed for the bone defect applied with the gelatin hydrogel incorporating PRP and fibrin incorporating PRP. However, no repairing was observed at the bone defect applied with free PRP, similar to the no treatment group. The bone mineral density increased by the gelatin hydrogel incorporating PRP application to a significantly great extent compared with other applications. Conclusion: The present study clearly indicates that the gelatin hydrogel incorporating PRP is a very promising tool to enable the PRP to promote the activity of bone repairing. References Marx RE, Carlson ER, Eichstaedt RM, et al: Platelet-rich plasma: Growth factor enhancement for bone grafts. Oral Surg Oral Med Oral Pathol 85:638, 1998 Tabata Y, Ikada Y: Protein release from gelatin matrices. Adv Drug Deliv Rev 31:287, 1998
bones of each animal. In the first group morselized autogenous calvarial bone was placed in one defect while the other remained empty. Group 2 had DBM putty (67% DBM) placed on one side and DBM gel (47% DBM) placed in the other. In Group 3 one defect was filled with a DBM putty covered with a 0.25-mm thick PLA/PGA (Lactosorb) sheet and the other defect was covered with the resorbable plate alone. Group 4 had CPC (Mimix) mixed with 25 mg BMP per cc placed in one defect and calcium phosphate cement alone was used in the other defect. Half the animals were sacrificed at 6 weeks and 12 weeks. Qualitative, radiologic, and histomorphometric analysis was then performed. Results: Histomorphometric results of Group 1 show incomplete bony healing in the unfilled defect and complete bridging of bone in the side filled with autogenous bone. Analysis of Groups 2 and 3 showed similar amounts of bone formation in between DBM gel/PLA/ PGA group and DMB gel alone (P ⬍.05). In Group 4 significantly more new bone formation was seen with the CPC and BMP than the CPC alone (P ⬍.05). Conclusions: PLA/PGA acid resorbable plating systems do not significantly reduce new bone formation when used with DBM putty. The addition of BMP to CPC promoted new bone formation suggesting that it may be a useful carrier. Both these techniques demonstrated new bone formation across the entire osseous defect while at the same time offering a hard protective barrier during the initial healing period. References
POSTER 28 Enhanced Bone Healing in Rabbit Calvarium Using Novel Bone Substitutes A.J. Haddad, DMD, 77-902 Gerrard Street West, Toronto, ON M5G 2A1 Canada (Sandor GKB; Clokie CML) Objective: Autogenous bone remains the gold standard in reconstruction of craniofacial defects. However, the limitations of autogenous bone have led to the development of bone substitutes. In previous work the use of osteoinductive bone substitutes have led to successful reconstruction of bony defects. However, these implants lack the ability to withstand compressive loading. In an attempt to address this problem the purpose of this study was to evaluate whether the use of resorbable plating systems made of polylactic/polyglycolic acid (PLA/PGA) and/or calcium phosphate cements (CPC) as carriers for these osteoinductive materials would allow bone regeneration. Materials and Methods: Forty New Zealand white rabbits were divided in 4 groups of 10 animals. Two 15 mm in diameter calvarial defects were made in the parietal 96
Clokie CM, Moghadam H, Jackson MT, et al: Closure of critical sized defects with allogenic and alloplastic bone substitutes. J Craniofac Surg 13:111, 2002 Schmitz JP, Hollinger JO: The critical size defect as an experimental model for craniomandibulofacial nonunions. Clin Orthop 205:299, 1986
Funding Source: Ontario Research and Development Challenge Fund.
POSTER 29 Ameloblastoma Treatment: Decompression Followed by Definitive Treatment Randy Bogard, MD, DMD, University of Missouri in Kansas City, School of Dentistry, Department of OMS, Truman Medical Center, Kansas City, MO (Abaza N; Mulligan JP) Introduction: The conventional ameloblastoma is a benign but locally aggressive tumor. Any attempts to remove the tumor by simple curettage results in recurrence rates of 55% to 90%. Unicystic ameloblastomas, on the other hand, are less aggressive and have a more AAOMS • 2003
bones of each animal. In the first group morselized autogenous calvarial bone was placed in one defect while the other remained empty. Group 2 had DBM putty (67% DBM) placed on one side and DBM gel (47% DBM) placed in the other. In Group 3 one defect was filled with a DBM putty covered with a 0.25-mm thick PLA/PGA (Lactosorb) sheet and the other defect was covered with the resorbable plate alone. Group 4 had CPC (Mimix) mixed with 25 mg BMP per cc placed in one defect and calcium phosphate cement alone was used in the other defect. Half the animals were sacrificed at 6 weeks and 12 weeks. Qualitative, radiologic, and histomorphometric analysis was then performed. Results: Histomorphometric results of Group 1 show incomplete bony healing in the unfilled defect and complete bridging of bone in the side filled with autogenous bone. Analysis of Groups 2 and 3 showed similar amounts of bone formation in between DBM gel/PLA/ PGA group and DMB gel alone (P ⬍.05). In Group 4 significantly more new bone formation was seen with the CPC and BMP than the CPC alone (P ⬍.05). Conclusions: PLA/PGA acid resorbable plating systems do not significantly reduce new bone formation when used with DBM putty. The addition of BMP to CPC promoted new bone formation suggesting that it may be a useful carrier. Both these techniques demonstrated new bone formation across the entire osseous defect while at the same time offering a hard protective barrier during the initial healing period. References
POSTER 28 Enhanced Bone Healing in Rabbit Calvarium Using Novel Bone Substitutes A.J. Haddad, DMD, 77-902 Gerrard Street West, Toronto, ON M5G 2A1 Canada (Sandor GKB; Clokie CML) Objective: Autogenous bone remains the gold standard in reconstruction of craniofacial defects. However, the limitations of autogenous bone have led to the development of bone substitutes. In previous work the use of osteoinductive bone substitutes have led to successful reconstruction of bony defects. However, these implants lack the ability to withstand compressive loading. In an attempt to address this problem the purpose of this study was to evaluate whether the use of resorbable plating systems made of polylactic/polyglycolic acid (PLA/PGA) and/or calcium phosphate cements (CPC) as carriers for these osteoinductive materials would allow bone regeneration. Materials and Methods: Forty New Zealand white rabbits were divided in 4 groups of 10 animals. Two 15 mm in diameter calvarial defects were made in the parietal 96
Clokie CM, Moghadam H, Jackson MT, et al: Closure of critical sized defects with allogenic and alloplastic bone substitutes. J Craniofac Surg 13:111, 2002 Schmitz JP, Hollinger JO: The critical size defect as an experimental model for craniomandibulofacial nonunions. Clin Orthop 205:299, 1986
Funding Source: Ontario Research and Development Challenge Fund.
POSTER 29 Ameloblastoma Treatment: Decompression Followed by Definitive Treatment Randy Bogard, MD, DMD, University of Missouri in Kansas City, School of Dentistry, Department of OMS, Truman Medical Center, Kansas City, MO (Abaza N; Mulligan JP) Introduction: The conventional ameloblastoma is a benign but locally aggressive tumor. Any attempts to remove the tumor by simple curettage results in recurrence rates of 55% to 90%. Unicystic ameloblastomas, on the other hand, are less aggressive and have a more AAOMS • 2003