Per Alberius

Osseous response to implanted natural bone mineral and synthetic hydroxylapatite ceramic in the repair of experimental skull bone defects

The purpose of this study was to assess and compare the osseous responses to implanted particles of resorbable anorganic xenograft bone mineral and non-resorbable dense synthetic hydroxylapatite of two different granule sizes. Four trephine calvarial defects were produced in each of 13 adult rabbits. The experimental materials were subsequently implanted in three defects, leaving the fourth defect for control purposes. Six animals were killed 4 weeks after surgery and seven at 14 weeks. The tissue responses were assessed by contact radiography, light microscopy, and histometry. The biocompatibility of the implants was confirmed. All defects healed uneventfully, although the resorbable hydroxylapatite seemed to promote initial bone regeneration. The importance to orthognathic surgery of early and effective healing of bone gaps, as well as of the advantage of implant resorbability to bone remodeling, are discussed.

OSTEOPROMOTION : A SOFT-TISSUE EXCLUSION PRINCIPLE USING A MEMBRANE FOR BONE HEALING AND BONE NEOGENESIS

The research reviewed in this paper constitutes a series of investigations intended to develop and evaluate a new membrane technique, which provides improved conditions for osteogenesis during healing of bone defects and restitution of earlier existing bone. The technique has also been shown to aid in bone grafting as well as having the capacity to create new bone for reconstructive purposes. According to this methodology, membranes are utilized to create a space in the tissue in which osteogenesis can occur relatively unimpeded. The paper provides a review of our initial animal experimental work as well as some clinical studies with special emphasis on membrane use in conjunction with dental implants. Possible mechanisms behind the efficacy of the membrane technique are reviewed, and future perspectives of development are also discussed. The osteopromotive membrane technique represents a principally new and major advance in bone biology and reconstructive skeletal surgery. Based on the results obtained by us and by others, the technique is presently utilized clinically in some routine applications. J Periodontol 1993; 64:1116-1128.

Maxillary alveolar ridge augmentation with onlay bone-grafts and immediate endosseous implants

Management of the atrophic maxilla can be a taxing surgical problems. One treatment alternative is to use autogenous bone transplants and immediate titanium fixture implantation. Despite the extensive literature on routine implant treatment of the edentulous jaws, only very few reports have dealt with the outcome of bone graft reconstructive surgery as part of the dental implant restoration. This study presents the treatment and healing results of 8 consecutive patients, who, over a period of 2 years and 8 months, were treated using onlay iliac bone grafts to atrophic maxillary alveolar ridges with immediate implant insertion. The patients were followed for 32-64 months. 83% of the fixtures (n = 46) were well-integrated. Two fixtures in each of 2 patients were lost due to traumatic bone-graft fractures. Palpatory bone-graft volume and prosthetic function were, with the exception of 1 patient, good. Radiological examination demonstrated preservation of the major part of the vertical dimension of the grafted bone. Patients assessment was of good aesthetics and intraoral function; 2 patients had minor phonetic problems. In conclusion, similar success to routine maxillary implant treatment can be achieved in the event of extreme maxillary bone deficiency, by bone grafting and immediate fixture insertion.

Factors in implant integration failure after bone grafting: An osteometric and endocrinologic matched analysis

In a retrospective analysis of 49 patients who received bone graft augmentation to the maxillary sinuses in conjunction with implant insertion, 11 patients had a significantly reduced success rate. The aim of the present study was to determine whether bone quality, as assessed by osteometry and selected haematologic and urinary tests, influences the integration of implants, and whether such data can be prognostically useful. Relative bone mass density (BMD%) differed significantly among these patients as compared to age- and sex-matched control patients receiving the same reconstructive treatment (P=0.01). Other parameters tested did not demonstrate any significant differences. In addition to local complications, general disorders, such as osteoporosis, must be considered in cases of excessive implant loss.

Early results from reconstruction of severely atrophic (class VI) maxillas by immediate endosseous implants in conjunction with bone grafting and Le Fort I osteotomy

This report presents our experience with 12 consecutive patients treated by the method of SAILER19, comprising bone grafting to the floor of the nose and the maxillary sinus after a Le Fort I inferior repositioning of the maxilla followed by immediate implantation of endosseous implants. The corticocancellous grafts were harvested from the iliac crest. Fifty-nine implants were inserted in the bone grafts and eight in the adjacent nongrafted bone. Fourteen implants (21%) had to be removed because of nonintegration, of which 10 had been placed in two patients. The follow-up ranged from 11 to 24 months. No implants have been lost after loading. Six patients received fixed prostheses, and four overdentures. The importance of complete preoperative positional stability of the bone grafts and implants is emphasized.

Injury Is a Major Inducer of Epidermal Innate Immune Responses during Wound Healing

We examined the importance of injury for the epidermal innate immune response in human skin wounds. We found that injury, independent of infiltrating inflammatory cells, generated prominent chemotactic activity toward neutrophils in injured skin because of IL-8 production. Furthermore, injury was a major inducer of the expression of antimicrobial (poly)peptides (AMPs) in skin wounds. In human skin, these injury-induced innate immune responses were mediated by activation of the epidermal growth factor receptor (EGFR). Consequently, inhibition of the EGFR blocked both the chemotactic activity generated in injured skin and the expression of the majority of the AMPs. The importance of injury was confirmed in mouse experiments in vivo, in which injury independent of infection was a potent inducer of AMPs in skin wounds. To our knowledge, these data thereby provide a previously unreported molecular link between injury and neutrophil accumulation and identify the molecular background for the vast expression of IL-8 and AMPs in wounded epidermis. Conceptually, these data show that the growth factor response elicited by injury is important for the recruitment of neutrophils in skin wounds.

Role of osteopromotion in experimental bone grafting to the skull: A study in adult rats using a membrane technique

This study explores the effect of an osteopromotive membrane technique in a mature animal model on the survival of membranous and endochondral bone inlays in mandibular defects and membranous bone onlays on the calvarial roof. Twenty-eight adult male rats received fibular or mandibular inlay bone grafts to trephine defects in the mandibular angle, as well as mandibular disc onlay grafts to the parietal and frontal bone regions. The results were assessed by gross inspection and light microscopy after 12 weeks. Membrane use markedly promoted bone deposition in the defects. The membranous bone inlays showed complete incorporation to the margins of the defect, whereas the endochondral grafts at all times were covered by a thin fibrous capsule and failed to incorporate. Onlay grafts generally resorbed substantially, but the grafts covered by a membrane seemed more active, developed an increased cancellous component, and showed less pronounced volumetric loss. The findings confirm the fact that a biological difference exists between membranous and endochondral bone. They also confirm the osteopromotive effect of the membrane technique, and suggest that the amount of bone needed for transplantation can be reduced using this method.

Sensibility following sagittal split osteotomy in the mandible: a prospective clinical study.

&NA; Bilateral sagittal split osteotomy may be associated with postoperative sensory deficiency in the area innervated by the inferior alveolar nerve. The aim of this study was to assess the neurosensory response of the inferior alveolar nerve after such surgery. Fifty consecutive patients receiving mandibular setback or advancement were investigated. Four different neurosensory tests were used: light touch, pin prick, static two‐point discrimination, and vibration thresholds. These tests were performed preoperatively, 2 days, as well as 3 months and 12 months postoperatively. The methodologic error was found negligible. The pin prick and light touch tests as well as vibratory thresholds often disclosed a short period of decreased local sensibility, whereas static two‐point discrimination displayed a slightly more extended postoperative sensory reduction. The patients did not experience any practical problems or essential drawbacks postoperatively. The only variable significantly associated with neurosensory disturbance was age. In conclusion, bilateral sagittal split osteotomy, when properly performed, must be considered a safe and reliable surgical technique, even from a neurosensory point of view. (Plast. Reconstr. Surg. 102: 325, 1998.)

Restoration of mandibular nonunion bone defects: An experimental study in rats using an osteopromotive membrane method

Standardized through-and-through critical size defects were created in rat mandibles. After 12 weeks, the sites revealed a massive ingrowth of soft connective tissue, forming a transosseous core filling the defects. Upon reentry, the soft tissue inside the remaining bone defects was removed. On one side of the jaw, the defect was covered both buccally and lingually with an expanded polytetrafluoroethylene (e-PTFE) membrane, but on the other side no membrane was placed. Histologic analysis after 6 weeks revealed an essentially complete healing with bone of the membrane-covered defects. No cartilage was present in any of the specimens. At the control sites (no membrane), the amount of newly produced bone showed variations, most through defects revealing the presence of a remaining central portion of connective tissue. This investigation thus showed that predictable and successful bone regeneration can be achieved by the osteopromotive membrane method in treatment of nonunion defects filled with mature connective tissue.

Bone Reactions to Tantalum Markers

To elucidate intramembranous bone reactions to tantalum bone markers, 0.8-mm tantalum balls were implanted in the craniofacial region of 9 male New Zealand white rabbits. After 1, 2, 4 and 16 weeks the animals were sacrificed for SEM. Implant stability for these intervals was controlled by roentgen stereophotogrammetry. Fibrocytes and deposed fibers were seen to immediately adhere to the ball surface, getting retention in its porosities. A successively increasing bony support was observed to have intimate junctions without intervening fibers or soft tissues. No apparent differences in bone reactions were seen between the neurocranial and splanchnocranial bones. Osseointegration confirmed the inertness of tantalum to bone tissue and strongly confirms its suitability for implantation in bone.