Scaffold-based rhBMP-2 therapy in a rat alveolar defect model: implications for human gingivoperiosteoplasty.
BACKGROUND
Primary alveolar cleft repair has a 41 to 73 percent success rate. Patients with persistent alveolar defects require secondary bone grafting. The authors investigated scaffold-based therapies designed to augment the success of alveolar repair.


METHODS
Critical-size, 7 x 4 x 3-mm alveolar defects were created surgically in 60 Sprague-Dawley rats. Four scaffold treatment arms were tested: absorbable collagen sponge, absorbable collagen sponge plus recombinant human bone morphogenetic protein-2 (rhBMP-2), hydroxyapatite-tricalcium phosphate, hydroxyapatite-tricalcium phosphate plus rhBMP-2, and no scaffold. New bone formation was assessed radiomorphometrically and histomorphometrically at 4, 8, and 12 weeks.


RESULTS
Radiomorphometrically, untreated animals formed 43 +/- 6 percent, 53 +/- 8 percent, and 48 +/- 3 percent new bone at 4, 8, and 12 weeks, respectively. Animals treated with absorbable collagen sponge formed 50 +/- 6 percent, 79 +/- 9 percent, and 69 +/- 7 percent new bone, respectively. Absorbable collagen sponge plus rhBMP-2-treated animals formed 49 +/- 2 percent, 71 +/- 6 percent, and 66 +/- 7 percent new bone, respectively. Hydroxyapatite-tricalcium phosphate treatment stimulated 69 +/- 12 percent, 86 +/- 3 percent (p < 0.05), and 87 +/- 14 percent new bone, respectively. Histomorphometry demonstrated an increase in bone formation in animals treated with hydroxyapatite-tricalcium phosphate plus rhBMP-2 (p < 0.05; 4 weeks) compared with empty scaffold.


CONCLUSIONS
Radiomorphometrically, absorbable collagen sponge and hydroxyapatite-tricalcium phosphate scaffolds induced more bone formation than untreated controls. The rhBMP-2 added a small but significant histomorphometric osteogenic advantage to the hydroxyapatite-tricalcium phosphate scaffold.
Nguyen
Phuong D
PD
New York, N.Y. From the Institute of Reconstructive Plastic Surgery, New York University School of Medicine, and the Department of Biomaterials and Biomimetics, New York University College of Dentistry.
Lin
Clarence D
CD
Allori
Alexander C
AC
Schachar
Jeffrey S
JS
Ricci
John L
JL
Saadeh
Pierre B
PB
Warren
Stephen M
SM
D020341:Absorbable Implants; D000540:Alveolar Ridge Augmentation / Q000379:methods*; D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects / Q000502:physiology; D002130:Calcium Phosphates / Q000494:pharmacology*; D002972:Cleft Palate / Q000601:surgery; D004195:Disease Models, Animal; D005260:Female; D005893:Gingivoplasty / Q000379:methods; D006801:Humans; D008297:Male; D019647:Oral Surgical Procedures / Q000379:methods; D010012:Osteogenesis / Q000187:drug effects* / Q000502:physiology; D010521:Periosteum / Q000601:surgery; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology*; D019651:Plastic Surgery Procedures / Q000379:methods*; D012307:Risk Factors; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D002130:Calcium Phosphates; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; C018392:tricalcium phosphate