Bone formation at recombinant human bone morphogenetic protein-2-coated titanium implants in the posterior mandible (Type II bone) in dogs.
BACKGROUND
Conventional oral/maxillofacial implants reach osseointegration over several months during which the titanium fixtures interact with alveolar bone. The objective of this study was to determine if adsorbing recombinant human bone morphogenetic protein-2 (rhBMP-2) onto a titanium porous oxide (TPO) implant surface might enhance or accelerate local bone formation and support osseointegration in a large animal oral/maxillofacial orthotopic model.


METHODS
Endosseous implants with a TPO surface were installed into the edentulated posterior mandible in eight adult Hound Labrador mongrel dogs. The implant surface had been adsorbed with rhBMP-2 at 0.2 or 4.0 mg/ml. TPO implants without rhBMP-2 served as control. Treatments were randomized between jaw quadrants. Mucosal flaps were advanced and sutured leaving the implants submerged. Clinical and radiographic evaluations were made immediately post-surgery, at day 10 (suture removal), and week 4 and 8 post-surgery. The animals received fluorescent bone markers at week 3, 4, and at week 8 post-surgery, when they were euthanized for histologic analysis.


RESULTS
TPO implants coated with rhBMP-2 exhibited dose-dependent bone remodelling including immediate resorption and formation of implant adjacent bone, and early establishment of clinically relevant osseointegration. The resulting bone-implant contact, although clinically respectable, appeared significantly lower for rhBMP-2-coated implants compared with the control [rhBMP-2 (0.2 mg/ml) 43.3+/-10.8%versus 71.7+/-7.8%, p<0.02; rhBMP-2 (4.0 mg/ml) 35.4+/-10.6%versus 68.2+/-11.0%, p<0.03].


CONCLUSIONS
rhBMP-2 adsorbed onto TPO implant surfaces initiates dose-dependent peri-implant bone re-modelling resulting in the formation of normal, physiologic bone and clinically relevant osseointegration within 8 weeks.
Wikesjö
Ulf M E
UM
Departments of Periodontics and Oral Biology & Maxillofacial Pathology, Laboratory for Applied Periodontal & Craniofacial Regeneration, Medical College of Georgia School of Dentistry, Augusta, GA 30912, USA. uwikesjo@mcg.edu
Xiropaidis
Andreas V
AV
Qahash
Mohammed
M
Lim
Won Hee
WH
Sorensen
Rachel G
RG
Rohrer
Michael D
MD
Wozney
John M
JM
Hall
Jan
J
D000818:Animals; D015519:Bone Density; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology*; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D001842:Bone and Bones / Q000033:anatomy & histology; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020007:Implants, Experimental; D008297:Male; D008334:Mandible / Q000601:surgery; D016348:Osseointegration / Q000187:drug effects*; D011897:Random Allocation; D011994:Recombinant Proteins / Q000494:pharmacology; D013499:Surface Properties; D014025:Titanium / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000494:pharmacology
D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D020099:Coated Materials, Biocompatible; D015921:Dental Implants; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; C009495:titanium dioxide; D014025:Titanium