ABSTRACT
UNLABELLED: Numerous experimental studies have been published about osteoinductive bone morphogenetic proteins (BMPs). However, to our knowledge there has been no detailed histological study of a mandibular defect in a large mammal, reconstructed using BMPs. We describe here the histological features of rhBMP-7-induced bone in mandibular defects in sheep. METHODS: A 35 mm osteoperiosteal defect was created at the parasymphyseal region of the mandible in six adult sheep. The continuity of the mandible was maintained using a bony plate, and rhBMP-7 was applied on a type I collagen carrier. Bone labels were injected at selected time intervals during the follow-up period. The animals were killed after 3 months and bone samples were examined histologically, histomorphometrically, and by fluorescence microscopy. RESULTS AND CONCLUSIONS: We found a mixture of woven and lamellar bone that contained many cells with large nuclei. This had not reorganised to form cortical bone and the rhBMP-7-induced bone was more porous than the native bone. The newly-formed bone restored both endosteal and periosteal layers. rhBMP-7-induced bone was biocompatible and induced no ossification of soft tissue or abnormal growth of nearby vital structures. The mineral apposition rate was 1.98 microm/day (range 0.62-5.63 microm/day), a value close to that reported in humans. This suggests that BMPs have a limited effect in accelerating the rate of mineralisation, but promote the pre-mineralisation processes, and perhaps the formation of woven bone.
Subject(s)
Bone Morphogenetic Proteins/therapeutic use , Bone Regeneration/drug effects , Mandible/drug effects , Transforming Growth Factor beta/therapeutic use , Animals , Bone Morphogenetic Protein 7 , Bone Plates , Bone Regeneration/physiology , Female , Mandible/anatomy & histology , Mandible/physiology , Microscopy, Fluorescence , Recombinant Proteins/therapeutic use , SheepABSTRACT
This paper discusses the use of extra-oral endosseous craniofacial implant (EOECI) therapy in irradiated bone. The survival rate of EOECIs in irradiated bone is reviewed and the controversy over the optimal time prior to place implants is described. The advantages and disadvantages of pre- and post-implant radiotherapy are addressed. The EOECI rehabilitation and osteoradionecrosis and the evidence of the potential role of hyperbaric oxygen are reviewed. Strategies for improving the clinical outcome of EOECIs are suggested.
Subject(s)
Cranial Irradiation/adverse effects , Maxillofacial Prosthesis Implantation , Maxillofacial Prosthesis , Animals , Head and Neck Neoplasms/radiotherapy , Head and Neck Neoplasms/rehabilitation , Humans , Hyperbaric Oxygenation , Mastoid/radiation effects , Mastoid/surgery , Osseointegration , Osteoradionecrosis/etiology , Osteoradionecrosis/therapy , Prosthesis Failure , Radiation Injuries/etiology , Radiation Injuries/therapy , Skull/radiation effects , Skull/surgery , Time FactorsABSTRACT
The published experience of extra-oral endosseous craniofacial implants (EOECIs) is reviewed. The definition of osseointegration, concept of success, the relative merit of one- or two-stage implant placement, EOECI design and control of peri-abutment skin infection are discussed. A plea is made for more consistent and objective reading of clinical experience of this technique.
Subject(s)
Osseointegration , Prostheses and Implants , Prostheses and Implants/trends , Prosthesis Implantation/trends , Prosthesis-Related Infections/prevention & control , Animals , Bone Plates , Bone Screws , Facial Bones/surgery , Forecasting , Humans , Prostheses and Implants/classification , Prosthesis Implantation/methods , Temporal Bone/surgery , Treatment OutcomeABSTRACT
We report our experience of endosseous implants designed to retain various types of facial prostheses that were inserted by the West of Scotland Oral and Maxillofacial Surgery Service between January 1988 and September 1998. Forty-seven patients were given a total of 150 implants, most of which were auricular (n= 85) or orbital (n= 53). The functioning success rates were 100% and 75%, respectively. Soft tissue infection was the commonest complication, and could occur at any time after exposure of the implant, suggesting that life-long follow-up is required.
Subject(s)
Dental Implantation, Endosseous , Maxillofacial Prosthesis Implantation , Adolescent , Adult , Child , Dental Implantation, Endosseous/adverse effects , Ear, External/surgery , Female , Hearing Aids , Humans , Male , Mastoid/surgery , Maxillofacial Prosthesis Implantation/adverse effects , Middle Aged , Nose/surgery , Orbit/surgery , Osseointegration , Prosthesis-Related Infections/etiology , Retrospective Studies , Scotland , Temporal Bone/surgery , Treatment OutcomeABSTRACT
Infection of soft tissues surrounding extra-oral craniofacial endosseous implants is a common clinical problem. The aim of this study was to analyse the microflora associated with such implants, in both health and disease. Eighteen patients with a total of 49 implants were studied. Each patient was seen on two occasions for both a clinical examination and for collection of microbiological samples, using swabs and paper points, from the peri-abutment soft tissues. Specimens were cultured on blood agar and on agars selective for staphylococci and yeasts. Isolates were identified and selective antibiotic susceptibility testing undertaken. No single organism emerged as a predominant cause of peri-abutment skin infection but Staphylococcus aureus, Gram-negative bacilli and yeasts were all present as potential pathogens in this context. Culture and sensitivity results should therefore guide the treatment of these infections.
