A prospective histomorphometric and cephalometric comparison of bovine bone substitute and autogenous bone grafting in Le Fort I osteotomies.

PURPOSE: The aim of the present study was the histomorphometric and cephalometric comparison of autogenous bone grafting of the anterior iliac crest and the application of bovine bone substitute concerning new bone formation and postoperative stability in patients undergoing orthognathic Le Fort I osteotomy. PATIENTS AND METHODS: Twenty-five patients requiring orthognathic surgery with Le Fort I osteotomy were included in this study. Patients were randomly divided into three groups receiving either autogenous iliac crest BONE grafting (BONE; n = 8) or xenogenic bovine bone grafting (Bio-Oss®) in INTER (n = 12) or in ONLAY (n = 5) position. Histomorphometric analysis was performed using trephine bone biopsies from the autogenous, respectively xenogenic bone grafting region. Postoperative stability was evaluated using teleradiographies of three different timepoints. RESULTS: All groups showed comparable mineralized fractions in bone biopsies of 50.2% (±13.2%) INTER, 46.48% (±12.3%) ONLAY and 57.1% (±20.6%) BONE as well as comparable percentage of connective tissue. Patients in the INTER-group revealed the lowest relapse rate of 20.5% (INTER) compared to 30.3% (ONLAY) and 33.0% (BONE). All groups underwent comparable maxillary advancement and healing time. CONCLUSIONS: Present results indicate that block shaped bovine bone substitute is a promising alternative to autogenous bone grafting to bridge the Le Fort I osteotomy gap in orthognathic surgery.

Injectable Hyaluronan Hydrogels with Peptide-Binding Dendrimers Modulate the Controlled Release of BMP-2 and TGF-ß1.

BMP-2 and TGF-ß1 released from injectable thermoresponsive hydrogels are studied in the presence and absence of branched macromolecules bearing BMP-2 or TGF-ß1 affinity binding peptides. The synthesized branched macromolecules and the gelling compositions before and after loading with either BMP-2 or TGF-ß1 are characterized physico-chemically and show a significantly lower amount of proteins released in the presence of the affinity binding peptide macromolecules. This study illustrates the potential of affinity binding peptide functionalized dendrimers to modulate the local delivery and availability of growth factors important for musculoskeletal regeneration therapies.

Multivalent dendrimers presenting spatially controlled clusters of binding epitopes in thermoresponsive hyaluronan hydrogels.

The controlled presentation of biofunctionality is of key importance for hydrogel applications in cell-based regenerative medicine. Here, a versatile approach was demonstrated to present clustered binding epitopes in an injectable, thermoresponsive hydrogel. Well-defined multivalent dendrimers bearing four integrin binding sequences and an azido moiety were covalently grafted to propargylamine-derived hyaluronic acid (Hyal-pa) using copper-catalyzed alkyne-azide cycloaddition (CuAAC), and then combined with pN-modified hyaluronan (Hyal-pN). The dendrimers were prepared by synthesizing a bifunctional diethylenetriamine pentaacetic acid core with azido and NHBoc oligo(ethylene glycol) aminoethyl branches, then further conjugated with solid-phase synthesized RGDS and DGRS peptides. Azido terminated pN was synthesized by reversible addition-fragmentation chain transfer polymerization and reacted to Hyal-pa via CuAAC. Nuclear magnetic resonance (NMR), high performance liquid chromatography, size exclusion chromatography and mass spectroscopy proved that the dendrimers had well-defined size and were disubstituted. NMR and atomic absorption analysis confirmed the hyaluronan was affixed with dendrimers or pN. Rheological measurements demonstrated that dendrimers do not influence the elastic or viscous moduli of thermoresponsive hyaluronan compositions at a relevant biological concentration. Finally, human mesenchymal stromal cells were encapsulated in the biomaterial and cultured for 21days, demonstrating the faculty of this dendrimer-modified hydrogel as a molecular toolbox for tailoring the biofunctionality of thermoresponsive hyaluronan carriers for biomedical applications.

Follow-up of implant survival comparing ficoll and bone marrow aspirate concentrate methods for hard tissue regeneration with mesenchymal stem cells in humans.

OBJECTIVE: Clinical follow-up of implant survival in 11 patients comparing two different methods for mesenchymal stem cell (MSC) isolation (Ficoll and bone marrow aspirate concentrate [BMAC]) applied in maxillary sinus augmentation. METHODS: Mononuclear cells, including MSCs, were concentrated with either Ficoll (control group, n=6 sinus) or BMAC (test group, n=12 sinus) and transplanted in combination with bovine bone mineral. A total of 50 implants were placed in a second surgical intervention (17 Ficoll/33 BMAC) and loaded after 4 months. Overall implant survival was assessed with a Kaplan-Meier model using package survival under R. RESULTS: Implant survival of the Ficoll group was 100% compared with the BMAC group, which had 93.4% survival (95% confidence interval, 0.849-1). The difference between the groups was not significant (p=0.381). CONCLUSION: The BMAC system is an effective and suitable "chair-side" method for clinical application in hard tissue regeneration.

Can mesenchymal stem cells and novel gabapentin-lactam enhance maxillary bone formation?

PURPOSE: Novel gabapentin-lactam (GBP-L) has shown its potency in enhancing new bone formation (NBF) in vitro. The objective of the present preclinical trial was to investigate the in vivo performance of GBP-L. MATERIALS AND METHODS: Bilateral sinus floor augmentations in 10 adult sheep were conducted. Bovine bone mineral (BBM) and mesenchymal stem cells (MSCs) combined with novel GBP-L were placed into the test sinus of each sheep. The BBM and MSCs alone served as the control on the contralateral side. Simultaneously, 3 dental implants were inserted in each maxillary sinus. The animals were sacrificed after 8 and 16 weeks, and the amount of NBF was analyzed using histomorphometry. The osteogenic potency of the MSCs was demonstrated using the colony-forming unit and differentiation assay. Statistical evaluation was performed using the Wilcoxon signed rank test and 3-factorial nonparametric analysis of variance. RESULTS: The histologic examination showed NBF in tight contact with the original bone in the control and test groups. The NBF was not significantly different between the test and control sites (P > .05). However, a highly significant difference in NBF between the apical and coronal sites in the specimens from the control and test groups was detected (P < .05). GBP-L did not alter the multipotency of the MSCs or impair NBF. CONCLUSIONS: Bone formation is initiated from the residual alveolar crest and along the implant. The elected mode of GBP-L application did not induce faster NBF. Alternate forms of application (eg, slow release or systemic administration) might clarify the controversial in vitro findings.

The effect of gabapentin-lactam hydroxamic acid derivatives on ovine osteoblast proliferation and phenotype: perspectives for tissue engineering application.

PURPOSE: Modern bone tissue engineering associated with mesenchymal stem cells (MSCs) provides promising treatment alternatives for the loss of bone, one of the foremost challenges in oral and craniofacial surgery today. The effect of gabapentin-lactam (GBP-L) and its analogs on osteogenic differentiated MSCs has not yet been deciphered. Consequently, this study investigates the effect of novel trans-8-tertbutylgabapentin-lactam (trans-8-TB-GBP-L) hydroxamic acid derivatives on metabolism, proliferation, and physiologic mineralization characteristics of ovine osteoblast cells. MATERIALS AND METHODS: Osteoblasts were extracted and prepared from sheep femoral heads and cultured in medium enriched with hydroxamic acid derivatives of trans-8-TB-GBP-L. The cell proliferation rate, cell metabolism, cell viability, and basic osteoblastic function were assessed. RESULTS: After 3 and 5 days of incubation, no significant increase in DNA content was detected in any of 12 test groups versus the control group. However, after 8 days of incubation, a significant increase of DNA contents in the test groups containing nanomolar concentrations of trans-8-TB-GBP-L hydroxamic acid derivatives was found. No significant aberration in metabolic activity was detected when any of the test substances were applied. ALP displayed similar activity rates among the test groups and the control at all time points. Calcification of osteoblastic cells occurred solely when nanomolar concentrations were used. CONCLUSION: Trans-8-TB-GBP-L hydroxamic acid derivatives do not interfere with physiologic function and phenotype of ovine osteoblasts. However, when applied at nanomolar concentrations, the assessed GBP-L derivatives significantly increased the cell proliferation rate after 8 days of incubation, indicating a dose-response curve with the maximum peak at nanomolar concentration and a retarded drug response between 5 and 8 days.

Evaluation of a new experimental model to study bone healing after ridge expansion with simultaneous implant placement--a pilot study in minipigs.

OBJECTIVE: To evaluate the suitability of a minipig model for the study of bone healing and osseointegration of dental implants following bone splitting and expansion of narrow ridges. MATERIAL AND METHODS: In four minipigs, the mandibular premolars and first molars were extracted together with removal of the buccal bone plate. Three months later, ridge splitting and expansion was performed with simultaneous placement of three titanium implants per quadrant. On one side of the mandible, the expanded bone gap between the implants was filled with an alloplastic biphasic calcium phosphate (BCP) material, while the gap on the other side was left unfilled. A barrier membrane was placed in half of the quadrants. After a healing period of 6 weeks, the animals were sacrificed for histological evaluation. RESULTS: In all groups, no bone fractures occurred, no implants were lost, all 24 implants were osseointegrated, and the gap created by bone splitting was filled with new bone, irrespective of whether BCP or a barrier membrane was used. Slight exposure of five implants was observed, but did not lead to implant loss. The level of the most coronal bone-to-implant contact varied without being dependent on the use of BCP or a barrier membrane. In all groups, the BCP particles were not present deep in the bone-filled gap. However, BCP particles were seen at the crestal bone margin, where they were partly integrated in the new bone. CONCLUSIONS: This new minipig model holds great promise for studying experimental ridge splitting/expansion. However, efforts must be undertaken to reduce implant exposure and buccal bone resorption.

Impact of autogenous concentrated bone marrow aspirate on bone regeneration after sinus floor augmentation with a bovine bone substitute--a split-mouth pilot study.

PURPOSE: Mesenchymal stem cells (MSC) with biomaterials have osteoinductive potential. The aim of this study was to evaluate early bone formation in xenogenic sinus grafts in a direct comparison with and without MSCs after 3 and 6 months. Literature on bone formation in pure xenogenic graft materials after 3 months in a human model is still lacking. MATERIALS AND METHODS: In a split-mouth design, seven patients with a bilateral highly atrophic posterior maxilla were included. The test side was grafted with MSCs from concentrated bone marrow aspirate admixed to the bone graft material. On the control side, pure bovine bone material was applied. Biopsies were taken navigated after 3 and 6 months. RESULTS: After 3 months, new bone formation in the control group was 11.8% (SD 6.2%) and in the test group 7.4% (SD 4.1%). After 6 months, the control group showed 13.9% (SD 8.5%) of new bone and the test group 13.5% NB (SD 5.4%). The fraction of bovine bone material after 3 months was 42.6% (SD 3.5%) in the test group and 34.9% (SD 11.8%) in the control group. After 6 months, the biomaterial content was comparable at both sides (test 36.2%, SD 7.8%; control 39.5%, SD 9.3%). CONCLUSIONS: There was no significant difference in new bone formation between the test and control group with n = 7. The results may be dominated by the high mineral content of the biomaterial but could nevertheless be valuable for meta-analysis in the future.

Effect of gabapentin-lactam and gamma-aminobutyric acid/lactam analogs on proliferation and phenotype of ovine mesenchymal stem cells.

PURPOSE: Classic tissue engineering consists of three components: scaffold, cells, and growth or differentiation factors. Currently, expensive bone morphogenetic proteins are the most common substance used for hard tissue regeneration. An alternative could be gamma-aminobutyric acid/lactam (GABA-lactam) analogs. MATERIALS AND METHODS: The effects of gabapentin-lactam, cis- and trans-8-tertbutyl-GABA-pentinlactam (trans-TB-GBP-L), and phenyl-GABA-lactam were tested in this study on ovine mesenchymal stem cell (MSC) proliferation. MSCs were selected from bone marrow aspirate concentrate by plastic adherence and amplified. Aliquots of the cells were incubated in medium, with four different concentrations of the GABA-lactam analogs dissolved in dimethyl sulfoxide. Cells in medium with and without dimethyl sulfoxide served as controls. Cell proliferation was tested with a nonradioactive assay. Before and after GABA-lactam analog influence, the MSC character was evaluated by the ability of the cells to differentiate into osteoblasts, chondrocytes, and adipocytes. RESULTS: Proliferation was significantly increased under the influence of the analogs, depending on their concentration. MSCs cultured in 1 nmol/L trans-TB-GBP-L showed the highest proliferation rate. The MSC character was not altered. CONCLUSIONS: GABA-lactam analogs could be suited to stimulate MSC proliferation for tissue engineering applications. Further in vivo studies are necessary to evaluate the possible clinical potential of GABA-lactam analogs for hard tissue regeneration.

Bone marrow aspirate concentrate used with bovine bone mineral to reconstruct vertical and horizontal mandibular defects: report of two techniques.

PURPOSE: Following initial positive reports of the use of bone marrow aspirate concentrate (BMAC) in combination with bovine bone mineral (BBM) in augmentation procedures, the technique was evaluated in patients with mandibular deficiency. MATERIALS AND METHODS: Two adult patients required surgical correction of a deficient alveolar ridge (one patient showed horizontal deficiency only, and the other patient presented with horizontal and vertical deficiency) prior to dental implant placement. In both patients, the reconstruction was performed with BBM in combination with mononuclear cells concentrated by the BMAC method using different techniques. RESULTS: The patients recovered well from all surgical procedures. Histologically, there was uniform bone formation, which allowed placement of dental implants. CONCLUSION: The results suggest that the use of BMAC in combination with BBM, without autogenous bone, has the potential to restore horizontal and vertical mandibular alveolar defects, providing a functional bone structure and allowing dental implant placement for subsequent prosthetic rehabilitation.

Evaluation of bone substitute materials: comparison of flat-panel based volume CT to conventional multidetector CT.

Over the last decade tissue engineering has emerged as a key factor in bone regeneration within the field of cranio-maxillofacial surgery. Despite this in vivo analysis of tissue-engineered-constructs to monitor bone rehabilitation are difficult to conduct. Novel high-resolving flat-panel based volume CTs (fp-VCT) are increasingly used for imaging bone structures. This study compares the potential value of novel fp-VCT with conventional multidetector CT (MDCT) based on a sheep sinus floor elevation model. Calcium-hydroxyapatite reinforced collagen scaffolds were populated with autologous osteoblasts and implanted into sheep maxillary sinus. After 8, 16 and 24 weeks MDCT and fp-VCT scans were performed to investigate the volume of the augmented area; densities of cancellous and compact bone were assessed as comparative values. fp-VCT imaging resulted in higher spatial resolution, which was advantageous when separating closely related anatomical structures (i.e. trabecular and compact bone, biomaterials). Fp-VCT facilitated imaging of alterations occurring in test specimens over time. fp-VCTs therefore displayed high volume coverage, dynamic imaging potential and superior performance when investigating superfine bone structures and bone remodelling of biomaterials. Thus, fp-VCTs may be a suitable instrument for intraoperative imaging and future in vivo tissue-engineering studies.

Surgical treatment of bisphosphonate-associated osteonecrosis of the jaw: technical report and follow up of 21 patients.

INTRODUCTION: Bisphosphonates are used to reduce skeletal related events in patients with bone consuming diseases such as osteoporosis and bone metastases. However recently there has been an increased awareness of bisphosphonate-associated necrosis of the jaws (BP-ONJ). Many authors propose conservative management in these cases but invariably the problem is not treated successfully allowing the bone defect to worsen. Recently there has been a move to treat this problem surgically. The aim of this retrospective study was to provide a surgical solution for patients suffering from BP-ONJ. MATERIALS AND METHODS: All patients presenting with BP-ONJ were treated with bone debridement of the affected area and multilayer wound closure. The considered variables were: gender, age, underlying diagnosis, type of bisphosphonate (BP) used, duration of bisphosphonate use, route of administration, location of the osteonecrosis, clinical symptoms, association with dental treatment and surgical outcome. RESULTS: Nineteen cases of a total of 21 demonstrated no recurrence of osteonecrosis during follow up (Mean 16 months - Range 12-24 months). One patient with a bilateral defect showed a dehiscence on one side and a small fistula on the contralateral side 6 weeks post-operatively and required revision surgery. Another patient developed a fistula after 4 weeks that was treated successfully with antibiotics and curettage. No patients had evidence of exposed bone, bland mucosa nor pain at the surgical site. CONCLUSION: The technique described can be recommended for patients with BP-ONJ if a conservative treatment fails.

Tissue-engineered polymer-based periosteal bone grafts for maxillary sinus augmentation: five-year clinical results.

PURPOSE: Augmentation of the maxillary sinus with allogenic or alloplastic materials, as well as autologous bone grafts, has inherent disadvantages. Therefore, the aim of our study was to evaluate the long-term clinical repair effect of autologous periosteal bone grafts on atrophic maxillary bone. PATIENTS AND METHODS: In the present retrospective cohort study, augmentation of the edentulous atrophic posterior maxilla was performed using autologous tissue-engineered periosteal bone grafts based on bioresorbable polymer scaffolds and, in a 1-step procedure, simultaneous insertion of dental implants. The clinical evaluation of 10 patients was performed by radiologic assessment of bone formation, with a follow-up of 5 years. Bone formation was further documented by measuring the bone height and by histologic examination. RESULTS: Excellent clinical and radiologic results were achieved as early as 4 months after transplantation of the periosteal bone grafts. The bone height remained significantly (P < .05) greater (median 14.2 mm) than the preoperative atrophic bone (median 6.9 mm) during the 5-year observation period. Histologically, the bone biopsy specimens of 2 patients obtained after 6 months showed trabecular bone with osteocytes and active osteoblasts. No signs of bone resorption, formation of connective tissue, or necrosis were seen. CONCLUSION: Our results suggest that the transplantation of autologous periosteal bone grafts and implantation of dental implants in a 1-step procedure is a reliable procedure that leads to bone formation in the edentulous posterior maxilla, remaining stable in the long term for a period of at least 5 years.

Bone marrow concentrate and bovine bone mineral for sinus floor augmentation: a controlled, randomized, single-blinded clinical and histological trial--per-protocol analysis.

PURPOSE: The purpose of this work was to evaluate the potential of substituting autogenous bone (AB) by bone marrow aspirate concentrate (BMAC). Both AB and BMAC were tested in combination with a bovine bone mineral (BBM) for their ability of new bone formation (NBF) in a multicentric, randomized, controlled, clinical and histological noninferiority trial. MATERIALS AND METHODS: Forty-five severely atrophied maxillary sinus from 26 patients were evaluated in a partial cross-over design. As test arm, 34 sinus of 25 patients were augmented with BBM and BMAC containing mesenchymal stem cells. Eleven control sinus from 11 patients were augmented with a mixture of 70% BBM and 30% AB. Biopsies were obtained after a 3-4-month healing period at time of implant placement and histomorphometrically analyzed for NBF. RESULTS: NBF was 14.3%±1.8% for the control and nonsignificantly lower (12.6%±1.7%) for the test (90% confidence interval: -4.6 to 1.2). Values for BBM (31.3%±2.7%) were significantly higher for the test compared with control (19.3%±2.5%) (p<0.0001). Nonmineralized tissue was lower by 3.3% in the test compared with control (57.6%; p=0.137). CONCLUSIONS: NBF after 3-4 months is equivalent in sinus, augmented with BMAC and BBM or a mixture of AB and BBM. This technique could be an alternative for using autografts to stimulate bone formation.

Making bone II: maxillary sinus augmentation with mononuclear cells--case report with a new clinical method.

We report a simplified method of using bone marrow aspirate concentrate (BMAC™) to regenerate hard tissue. The results suggest that BMAC™ combined with a suitable biomaterial can form sufficient bone within 3 months for further implants to be inserted, and at the same time minimise morbidity at the donor site.

Influence of rhBMP-2 on bone formation and osseointegration in different implant systems after sinus-floor elevation. An in vivo study on sheep.

BACKGROUND: Several studies have reported certain bone morphogenic proteins (BMPs) to have positive effects on bone generation. Although some investigators have studied the effects of human recombinant BMP (rhBMP-2) in sinus augmentation in sheep, none of these studies looked at the placement of implants at the time of sinus augmentation. Furthermore, no literature could be found to report on the impact that different implant systems, as well as the positioning of the implants had on bone formation if rhBMP-2 was utilized in sinus-lift procedures. PURPOSE: The aim of this study was to compare sinus augmentation with rhBMP-2 on a poly-d, l-lactic-co-glycolic acid gelatine (PLPG) sponge with sinus augmentation with autologous pelvic cancellous bone in the maxillary sinus during the placement of different dental implants. MATERIALS AND METHODS: Nine adult female sheep were submitted to bilateral sinus-floor elevation. In one side (test group) the sinus lift was performed with rhBMP-2 on a PLPG-sponge, while the contralateral side served as the control by using cancellous bone from the iliac crest. Three different implants (Bränemark(®), 3i(®) and Straumann(®)) were inserted either simultaneously with the sinus augmentation or as a two staged procedure 6 weeks later. The animals were sacrificed at 6 and 12 weeks for histological and histomorphometrical evaluations during which bone-to-implant contact (BIC) and bone density (BD) were evaluated. RESULTS: BD and BIC were significantly higher at 12 weeks in the test group if the implants were placed at the time of the sinus lift (p<0.05). No difference was observed between the different implant systems or positions. CONCLUSIONS: The use of rhBMP-2 with PLPG-sponge increased BIC as well as BD in the augmented sinuses if compared to autologous bone. Different implant systems and positions of the implants had no effect on BIC or BD.

Clinical aspects of a 2.0-mm locking plate system for mandibular fracture surgery.

PURPOSE: The use of a 2.0-mm locking plate system was evaluated in mandibular surgery. PATIENTS AND METHODS: 53 patients (42 male, 11 female) with a total of 56 mandibular fractures were treated with a 2.0-mm mini-locking-plate system and retrospectively examined. Gender, age, cause of fracture, surgical access, classification of fractures, osteosynthesis, postsurgical findings and complications were evaluated. RESULTS: Assault in male patients (mean age 31) was the most common aetiological factor. Fractures in women (mean age 43 years) mostly occurred due to falls. Mandibular angle fractures were the most common and this anatomical site also presented the highest complication rate. Only 6% of patients had minor occlusal disturbance postoperatively, and minor complications (infections and dehiscence) occurred in 14% of patients in this study. Major complications only occurred in one patient included in the study (1.9%). Risk factors for the development of complications in this series were a history of alcohol or tobacco use, mandibular angle fractures, associated facial fractures, presurgical occlusal disturbance and concomitant dental infections. Surgical access to the fracture and the interval from injury to surgery was not associated with the development of complications. CONCLUSIONS: The use of a 2.0-mm locking plate system with its advantages of improved handling characteristics, increased stability, shorter surgical time and the preservation of bony perfusion is a viable alternative to conventional miniplates in the management of mandibular fractures.

Mesenchymal stem cells and bovine bone mineral in sinus lift procedures--an experimental study in sheep.

INTRODUCTION: New reconstructive and less invasive methods have been searched to optimize bone formation and osseointegration of dental implants in maxillary sinus augmentation. PURPOSE: The aim of the presented ovine split-mouth study was to compare bovine bone mineral (BBM) alone and in combination with mesenchymal stem cells (MSCs) regarding their potential in sinus augmentation. MATERIAL AND METHODS: Bilateral sinus floor augmentations were performed in six adult sheep. BBM and MSCs were placed into the test side and only BBM in the contra-lateral control side of each sheep. Animals were sacrificed after 8 and 16 weeks. Augmentation sites were analyzed by computed tomography, histology, and histomorphometry. RESULTS: The initial volumes of both sides were similar and did not change significantly with time. A tight connection between the particles of BBM and the new bone was observed histologically. Bone formation was significantly (p = 0.027) faster by 49% in the test sides. CONCLUSION: The combination of BBM and MSCs accelerated new bone formation in this model of maxillary sinus augmentation. This could allow early placement of implants.

Mesenchymal stem cells and inorganic bovine bone mineral in sinus augmentation: comparison with augmentation by autologous bone in adult sheep.

Our aim was to compare the osteogenic potential of mononuclear cells harvested from the iliac crest combined with bovine bone mineral (BBM) (experimental group) with that of autogenous cancellous bone alone (control group). We studied bilateral augmentations of the sinus floor in 6 adult sheep. BBM and mononuclear cells (MNC) were mixed and placed into one side and autogenous bone in the other side. Animals were killed after 8 and 16 weeks. Sites of augmentation were analysed radiographically and histologically. The mean (SD) augmentation volume was 3.0 (1.0) cm(3) and 2.7 (0.3) cm(3) after 8 and 16 weeks in the test group, and 2.8 (0.3) cm(3) (8 weeks) and 2.8 (1.2) cm(3) (16 weeks) in the control group, respectively. After 8 weeks, histomorphometric analysis showed 24 (3)% BBM, and 19 (11)% of newly formed bone in the test group. The control group had 20 (13%) of newly formed bone. Specimens after 16 weeks showed 29 (12%) of newly formed bone and 19 (3%) BBM in the test group. The amount of newly formed bone in the control group was 16 (6%). The results show that mononuclear cells, including mesenchymal stem cells, in combination with BBM as the biomaterial, have the potential to form bone.

Bone engineering-vitalisation of alloplastic and allogenic bone grafts by human osteoblast-like cells.

Human osteoblasts on non-sintered hydroxyapatite and demineralised bone matrix (DBX) were analysed in vitro to find out whether they would be suitable for reconstruction of bones in oral surgery. Human osteoblasts were isolated from the jaw during routine dental operations and seeded onto the two biomaterials. Cells were characterised by assay of alkaline phosphatase, detection of type 1 collagen, and production of osteocalcin. After 21 days of cultivation, the cell/biomaterial constructs were examined by scanning electron microscopy, thin sections, and propidium iodide/fluorescein diacetate staining. The osteoblasts formed a vital multiple cell layer on DBX within 3 weeks of cultivation. On hydroxyapatite, the cells showed no tendency to proliferate or migrate onto the synthetic biomaterial, or to form well-spread and viable cell constructs. These findings suggest that surface morphology or the presence of osteoinductive factors may have an important role in the adhesion and proliferation of osteoblasts. Human DBX can be colonised by human osteoblast-like cells in vitro, indicating the potential of allogeneic carriers for future procedures in bone engineering.