Saliva induces expression of antimicrobial peptides and promotes intracellular killing of bacteria in keratinocytes by epidermal growth factor receptor transactivation.

BACKGROUND: Wounds in the oral cavity, constantly exposed to both saliva and bacteria, heal quickly without infection. Furthermore, during licking of skin wounds, saliva promotes wound healing and plays a role in keeping the wound free of infection. OBJECTIVES: To investigate whether saliva induces expression of antimicrobial peptides (AMPs) in human epidermal keratinocytes and whether saliva promotes clearance of intracellular bacteria in these cells. METHODS: Expression of AMPs was investigated in the oral mucosa and ex vivo injured skin by immunohistochemistry. Human beta-defensin-3 expression was investigated in epidermal keratinocytes after saliva stimulation, using real-time polymerase chain reaction and immunofluorescence. RESULTS: We found higher expression of AMPs in the oral mucosa than in the epidermis. Saliva accelerated the injury-induced expression of AMPs in human skin ex vivo and was a potent inducer of the expression of AMPs in epidermal keratinocytes. The expression of AMPs was induced by metalloproteinase-dependent epidermal growth factor receptor (EGFR) transactivation mediated by a salivary lipid. Saliva increased the intracellular clearance of Staphylococcus aureus in keratinocytes through EGFR activation. CONCLUSIONS: These findings suggest a previously unreported role of saliva in innate immunity and demonstrate for the first time that saliva induces gene expression in epidermal keratinocytes.

Some basic factors essential to autogeneic nonvascularized onlay bone grafting to the craniofacial skeleton.

The aim of this review is to provide a background on the experiences gained experimentally with autogeneic nonvascularized onlay bone transplantation, survey the most essential information in the medical literature, and to present modern trends and future expectations in bone graft science.

Effects of rhBMP-2 and osteopromotive membranes on experimental bone grafting.

A problem with using autogeneic bone for onlay grafting is its degree of incorporation and volumetric persistence. This study explored whether improved graft volumetric maintenance can be achieved by recombinant human bone morphogenetic protein-2 (rhBMP-2) and whether a combination of rhBMP-2 and osteopromotive membranes is advantageous in this respect. Unicortico-cancellous bone grafts were positioned below the temporal muscle bilaterally in 48 adult Lewis rats. The recipient bone was ground, and the grafted area was randomly treated according to one of eight different alternatives. Two doses of rhBMP-2 (4 microg/80 microl or 32 microg/80 microl buffer) in a collagenous carrier were tested, with or without coverage with expanded polytetrafluoroethylene membranes. As controls, membrane and carrier, alone or in combination, and onlay grafts only were used. The results were evaluated after 4 and 20 weeks by routine histologic examination and immunohistochemical labeling for various bone and cartilage matrix proteins. After 4 weeks, rhBMP-2-treated grafts showed complete integration, whereas for controls, only the membrane-alone group attained incorporation after 20 weeks. The combined treatment with high-dose rhBMP-2 and membrane demonstrated, as compared with the remaining rhBMP-2 groups, pronounced bone formation and less graft resorption, resulting in maintained or increased graft size. This was observed after 4 weeks, and the result remained at 20 weeks. Treatment with high-dose rhBMP-2 without membrane placement, in contrast, resulted in extensive resorption and graft size reduction at 20 weeks. Control groups showed less success in graft size persistence. It was concluded that a combination of high-dose rhBMP-2 and osteopromotive membranes had a synergistic effect, leading to rapid, complete graft integration and size maintenance. In the absence of a membrane, the protein seemed to accelerate the remodeling of the graft.

Two-stage maxillary sinus reconstruction with endosseous implants: a prospective study.

The aim of this prospective study was to evaluate the results of 2-stage maxillary sinus reconstruction using titanium implants placed into iliac corticocancellous bone blocks previously grafted to the floor of sinuses. Fifty consecutive patients received 314 Brånemark implants of varying lengths; 202 implants were placed in the grafted bone and 112 were placed in the adjacent anterior maxillary alveolar process, which had received buccal onlay bone grafts. Follow-up time was 9 to 48 months after implant placement, which was accomplished 5 months after bone grafting. Eighty-four percent of the implants were integrated into the grafted sinuses and 75% were integrated into the anterior graft. Six patients (12%) lost implants in strategic positions, leading to secondary implant placement prior to fabrication of fixed prostheses. Thirty-eight patients (76%) received fixed prostheses. Only 5 individuals (10%) attained permanent implant-anchored overdentures. One patient lost all implants. The total implant survival rate (80.9%) and the survival rate of the fixed prostheses (100%) compare favorably with other reports.

Osteopontin and bone sialoprotein distribution at the bone graft recipient site.

BACKGROUND: The area in close proximity to a bone graft is subject to marked remodeling activity, which may dramatically affect graft survival. OBJECTIVE: To specifically analyze the effects at the recipient bed-onlay graft interface. DESIGN: In 22 adult Lewis rats, bicortical grafts were positioned below the temporal muscle and subperiosteally over the parietal bone. The recipient bone was left intact or ground to remove the external cortical layer, thereby exposing the graft to the osteopotent cells of the bone marrow. The rats were killed after 4 or 20 weeks. The outcome was assessed by routine histologic examination and immunohistochemical labeling for 2 bone matrix proteins, osteopontin and bone sialoprotein, which are involved in bone resorption and formation, respectively. RESULTS: Placement of the grafts submuscularly or grinding of the outer cortical layer of the host bed increased recipient site resorption. Resorptive activity (labeling) was concentrated to a subzone below the surface of the recipient bone; neither the graft surface nor the interface soft tissues were labeled. CONCLUSION: The successive loss of skeletal contour after bone grafting, in many cases, may largely result from recipient site failure rather than graft size reduction.

Importance of bone graft quality for implant integration after maxillary sinus reconstruction.

OBJECTIVE: The aim of this study was to determine whether bone quality, as assessed by osteometry and histologic parameters, can be used to predict implant integration in conjunction with maxillary sinus reconstruction. STUDY DESIGN: Twelve patients with severely atrophied maxillary alveolar processes were treated through use of a two-stage surgical reconstructive strategy with implant placement 4 months after bone grafting. Bone biopsy specimens taken from the iliac crest peroperatively and from the sinus inlay sites 1, 2, 4, 6, or 12 months postoperatively were analyzed by light microscopy and osteomorphometry. Bone mineral content was measured by osteometry. RESULTS: Osteometric and osteomorphometric data (trabecular bone volume [%], assessment of chromatin staining, and an osteocyte index) registered for the biopsy specimens were not statistically correlated with implant failure. CONCLUSIONS: Prognostic evaluation of implant survival is difficult. The tested methods did not contribute to the improvement of guidelines for the clinical handling of these patients.

Autoclaved bone for craniofacial reconstruction: effects of supplementation with bone marrow or recombinant human fibroblast growth factor-2.

Replantation of resected bone after autoclaving is employed by many units in both craniofacial and orthopedic tumor reconstructive surgery. The procedure is attractive because it maintains the original anatomy, is reliable, and provides a good immediate clinical result. However, doubts have been raised about the ability of the autoclaved bone to revitalize. The present study aimed to explore, in an animal model, the revitalization of autoclaved bone and to determine whether it would be possible to enhance graft revitalization using either autogeneic bone marrow or recombinant human fibroblast growth factor-2, a peptide with stimulatory effects on both endothelial and osteogenic cells. Twenty-eight adult rats were subjected to bilateral parietal cranioplasties (4 x 6 mm), and 75 percent of the grafts were subjected to autoclaving (121 degrees C; 20 minutes) and subsequently treated randomly according to one of the following strategies: no further treatment, or supplementation with bone marrow or recombinant human fibroblast growth factor-2. The remaining grafts were replanted as fresh autografts. The results were evaluated after 4 and 12 weeks by radiologic, histologic, and histomorphometric analyses. After 4 weeks, no major differences were observed between treatments. At 12 weeks, however, no distinction in graft revitalization between autografts and autoclaved grafts supplemented with recombinant human fibroblast growth factor-2 was observed, whereas autoclaved grafts with or without bone marrow displayed significantly less revitalization compared with autografts. The results indicate that autoclaved bone will revitalize by remodeling, and that the efficacy of this process can be increased significantly by simultaneous supplementation with recombinant human fibroblast growth factor-2.

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

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.

Osteopromotive membranes enhance onlay integration and maintenance in the adult rat skull.

This study aimed to evaluate the effect of an osteopromotive membrane technique on onlay bone graft survival. Unicortical bone grafts were positioned bilaterally below the temporal muscle in 21 adult Lewis rats. In 14 rats, the bone graft on the right side was covered by an expanded polytetrafluoroethylene GORE-TEX membrane, whereas that on the left side was left uncovered. Seven rats were killed after 12 (group 1) and 20 (group 2) weeks, respectively. The remaining animals (n = 7, group 3) received membranes bilaterally, of which the right-sided membrane was removed after 12 weeks, and these animals were killed after 20 weeks. The specimens were assessed by routine histology and immunohistochemical labelling for various matrix proteins. After 12 weeks (group 1), size differences between the sides were not significant, although all control onlay bone grafts showed microscopic signs of pronounced resorption. At 20 weeks (group 2), graft integration was more complete on the membrane side. For group 3, the height was significantly more preserved on the side where the membrane was not removed. Immunolabelling demonstrated a more intense bone remodelling at the membrane sites. Membrane treatment resulted in improved graft integration and significantly greater size persistence, but complete height was not maintained.

Dental implant survival in the irradiated jaw: a preliminary report.

Seventeen oral cancer patients (47 to 78 years, mean 67) were treated with external radiation in areas that included future implant sites. Implants were placed in the irradiated jaws after a period of 18 to 228 months (mean 88 months). The patients received 103 implants and were followed for 1 to 62 months (mean 21 months) after implant loading. The cumulative survival rate of the implants after 1 year was 97% in the mandible and 92% in the maxilla. While the irradiation dose used did not affect implant survival, this result may possible be influenced by the addition of hyperbaric oxygen treatment for patients receiving more than 50 Gy. Irradiation for treatment of oral cancer does not seem to reduce the survival rate of implants as compared to those placed in the nonirradiated jaw.

Repeated bone repositioning in the growing rabbit calvarium hampers bone segment incorporation.

There has been concern among surgeons that multiple extended craniofacial procedures might be detrimental to the viability of the involved skeletal structures. This study aimed to explore the result of repeated bone repositionings in the growing rabbit calvaria. Seven immature rabbits were subjected to a three-stage surgical procedure, implying that four calvarial bone segments were originally harvested and repositioned according to a rotational scheme; after 6 weeks only three of the bone segments were harvested and repositioned and, finally, after an additional period of 6 weeks, two segments were repositioned. The results were evaluated by radiographic, histologic (with a special scoring system), and histomorphometric analysis. It was found that one or two cranioplasties did not markedly affect graft incorporation, but three procedures significantly reduced graft revascularization and integration. The findings are discussed with special reference to syndromic craniofacial disorders.

Sinus inlay bone augmentation: comparison of implant positioning after one- or two-staged procedures.

PURPOSE: This study was undertaken to compare implant angulation and position after one- or two-stage sinus inlay bone augmentation. PATIENTS AND METHODS: Twenty patients were retrospectively selected; group 1 (n = 10) was operated on with a one-stage procedure, and group 2 (n = 10) with a two-stage operation. Casts processed for the final permanent or temporary bridgework were collected and photographed from an oblique anterior view paralleling the alveolar crest on the right and left sides, as well as from an occlusal view. The angle between impression pins inserted in the abutments relative to the true vertical was recorded. In the occlusal view, the midpoints of the abutments were related to an individual computerized superimposed parabola. RESULTS: The implants inserted during the one-stage procedure were generally placed more palatally (Wilcoxon rank sum test, P = .0101) and angled more palatally (P = .0009) compared with those placed with the two-stage operation. CONCLUSION: This study showed that the two methods of treating patients by sinus inlay bone augmentation differed significantly with regard to placement and angulation of the implants. A two-stage procedure seems to offer the surgeon more optimal conditions for positioning the implants.

Bone graft incorporation after cortical perforations of the host bed.

A fundamental issue in onlay bone graft persistence is the unpredictable extent of incorporation and volumetric maintenance of the graft. The purpose of this study was to evaluate the effects on integration of onlays, with either their cancellous or cortical portion facing toward the host bed, positioned over cortical perforations at the recipient site. Tibial or femoral unicortical bone grafts were harvested from isogeneic donors and positioned subperiostally on each tibia of 22 adult Lewis rats. On the experimental side, the recipient outer cortical bone surface received multiple perforations, 0.25 mm in diameter. The contralateral side served as a control (no cortical perforations). The findings were assessed after 4 and 20 weeks using routine histologic and immunohistochemistry techniques. Cortical perforations induced a migration of the recipient bone marrow into the graft as well as a reduced size diminution. More cortical bone remodeling and marginal lamellar bone apposition were observed after orientating the cortical portion of the graft toward the recipient site. These observations may be useful clinically to improve long-term success after autogeneic bone grafting.

Onlay bone graft behaviour after marrow exposure of the recipient rat skull bone.

This study aimed to evaluate the effects on incorporation of onlay grafts after exposure of the marrow of the skull recipient bed. Tibial or femoral uni- and bicortical bone grafts were positioned subperiosteally or submuscularly in the parietal and temporal region, respectively, of 28 adult rats. The recipient bed was ground to remove the external cortical layer and expose the underlying marrow. The outcome was assessed after four, 12, and 20 weeks by routine histology and immunohistochemical labelling for various bone and cartilage proteins. Marrow exposure resulted in an explosive bone formation, prompt graft incorporation, earlier onset of bone remodelling, but also localized resorption at the host bed due to increased vulnerability to pressure. Graft height loss was similar relative to previous observations by us using the same experimental model but without exposure of the marrow. The investigated proteins were identified at various locations and with different temporal sequences; the technique contributed to a diversified appreciation of graft behaviour. The findings emphasize the essential role of the bone marrow constituents to bone graft incorporation.

Effect of cortical perforations of both graft and host bed on onlay incorporation to the rat skull.

The mechanisms involved in the integration of autogeneic bone grafts still attract much interest due to their clinical importance. The purpose of this study was to obtain data on the effects of a combination of cortical bone perforations both at the recipient site and the inner layer of a bicortical graft. 12 adult rats obtained femoral or tibial bicortical bone grafts from isogeneic donors to the tibia, one on each leg. On the experimental side, both the recipient bed and the inner cortical graft layer received multiple perforations (0.25 mm in diameter), while on the control side, only perforations of the recipient cortical bed were made. The findings were assessed by routine histology and immunohistochemical analysis for some bone and cartilage matrix proteins after 4 and 20 weeks. The combined cortical perforations of the graft and the host bed induced a locally improved bony incorporation of the graft and a corticalization of the graft marrow, implying improved mechanical stability. The graft height persistence was similar between groups. Intense labelling of the bone matrix proteins was apparent in all bone tissue and by diversified intensity at its various components, demonstrating ongoing remodeling activities. PRELP and fibromodulin mainly outlined the soft tissues surrounding the graft and compact bone sealing off the graft marrow. Immunolabelling contributed a more delicate picture of the mechanisms involved in graft incorporation.

Failure of onlay bone grafts to integrate over the calvarial suture: observations in adult isogeneic rats.

Bone grafting constitutes an important tool in cranio-maxillofacial skeletal reconstruction and augmentation. Much effort has been directed to improve graft survival and volumetric maintenance. The effects of the sutural tissue proper on graft incorporation has not yet been explored. The purpose of this report was to analyze the effects of positioning an onlay graft over a non-growing sutural region. Twelve adult rats received femoral or tibial uni- or bicortical grafts placed over the temporal suture. The findings were assessed by routine microscopy and immunohistochemistry after 4, 12, and 20 weeks. The sutural tissue expanded between the graft and the host bed in an umbrella-like pattern, which locally inhibited graft incorporation. Of the tested cartilage and bone proteins and proteoglycans, labelling was distinct only for osteopontin and fibromodulin, indicating a moderate remodelling activity in the area. The importance and consequences of the findings are discussed.

Retrospective analysis of one-stage maxillary sinus augmentation with endosseous implants.

The aim of the present retrospective study was to evaluate the results of a one-stage reconstructive procedure using titanium implants placed in iliac corticocancellous bone blocks grafted to the floor of maxillary sinuses. Forty-nine patients received 314 Brånemark implants, of which 171 implants of various lengths were placed in the grafted bone and 143 implants in the adjacent maxillary alveolar process (which includes 11 implants placed in onlay grafts). Five patients also received onlay grafts to the anterior maxilla. Follow-up time was 3 to 49 months after abutment connection, which was performed 9 months after implant placement. Eighty-two percent of the implants were successfully integrated in the grafted area and 84.8% in the adjacent bone. Eleven patients (22.4%) lost one to four implants or a few implants in strategic positions, requiring secondary implant placement prior to the manufacturing of fixed prostheses, whereas 35 (71.4%) received primary fixed restorations. Only two individuals (4.1%) received permanent implant-supported overdentures. Assessments of esthetics, phonetics, and function were made by the surgical-prosthodontic team and compared with those of the patients. Opinions regarding the functional outcome of treatment appeared least correlated. The total implant survival rate compares favorably with other reports.

Influence of surrounding soft tissues on onlay bone graft incorporation.

OBJECTIVES: This investigation aimed to evaluate the influence of three different soft tissue environments on onlay bone graft incorporation into the craniomaxillofacial skeleton and to follow this process immunohistochemically by staining for some bone and cartilage matrix proteins and proteoglycans. STUDY DESIGN: Femoral and tibial bone grafts, either uni- or bicortical, were placed subperiosteally, submuscularly, and intramuscularly in 36 identically sized and aged isogeneic rats. The results were evaluated after 4, 12, and 20 weeks. RESULTS: Corticocancellous grafts showed a more extensive incorporation and more pronounced local resorption. Bicortical grafts produced more resorption of the recipient site, which oftentimes resulted in the graft being almost level with the surrounding bone. The marrow space of both graft types was sealed off by compact bone formation. Intense labeling of tested bone matrix proteins at various parts of the graft-host area was demonstrated. Ultimate graft height was significantly reduced for most groups, but no major differences between groups were registered. Intramuscularly positioned control grafts ultimately showed signs of lacking viability and reduced labeling of cartilage matrix proteins. CONCLUSIONS: These findings indicate that either type of graft had its drawbacks and that further studies to enhance integration and size maintenance are necessary to improve overall graft persistence. Immunolabeling may help to identify essential mechanisms in and find markers of graft incorporation.

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.

Experience with e-PTFE membrane application to bone grafting of cleft maxilla.

Previous clinical studies and animal experiments have demonstrated that the placement of expanded polytetrafluoroethylene (e-PTFE) membranes (GORE-TEX) may be valuable for bone regeneration in nonosteogenic areas. This study aimed to explore the application of this technique to bone grafting of wide alveolopalatal clefts. Ten patients with bilateral clefts were selected and during a 2-week period, all received autogenic cancellous iliac bone bilaterally. The membrane was placed nasally and orally on the larger cleft side and removed after 3-6 months. All patients have been followed for 14 months. Bone graft incorporation was successful except for one patient (membrane side), who was regrafted 1 year later. However, soft-tissue problems with membrane exposure occurred in the majority of patients, while on the nonmembrane side, healing was uneventful in all cases. Further research in membrane technology is necessary before this method can be accepted for cleft grafting.