Optimal microvessel density from composite graft of autogenous maxillary cortical bone and anorganic bovine bone in sinus augmentation: influence of clinical variables

Comprehensive three-dimensional cone beam computed tomography assessment unilateral alveolar cleft reconstruction using autologous iliac cancellous bone combined with deproteinized bovine bone: A clinical retrospective evaluation

Large-volume autologous iliac cancellous bone grafting for alveolar cleft may lead to undesirable bone resorption and susceptible donor-site morbidity, whereas the addition of deproteinized bovine bone (DBB) could optimize outcomes. This study aimed to evaluate the effectiveness of combining autologous iliac bone with DBB using three-dimensional cone beam computed tomography (3D-CBCT) for better analysis of bone generation than conventional evaluation methods. Thirty-six patients with unilateral alveolar cleft were assigned into two groups. Group A (n = 21) underwent autogenous cancellous bone graft harvested from the anterior iliac crests, while Group B (n = 15) received a composite of autogenous iliac cancellous bone and DBB. Patients in Group B displayed higher bone filling rates (P < 0.0001) and lower bone absorption rates (P < 0.001) than those in Group A at both 6 months and 1 year postoperatively. Additionally, there were directional differences in bone absorption within the bone grafts, with more absorption observed on the alveolar crest and palatal sides than that on the nasal and labial sides (P < 0.001). This study demonstrates that employing a combination of DBB and autologous bone in alveolar cleft repair achieves better outcomes of bone grafting.

Emerging factors affecting peri-implant bone metabolism

Implant dentistry has evolved to the point that standard implant osseointegration is predictable. This is attributed in part to the advancements in material sciences that have led toward improvements in implant surface technology and characteristics. Nonetheless, there remain several cases where implant therapy fails (specifically at early time points), most commonly attributed to factors affecting bone metabolism. Among these patients, smokers are known to have impaired bone metabolism and thus be subject to higher risks of early implant failure and/or late complications related to the stability of the peri-implant bone and mucosal tissues. Notably, however, emerging data have unveiled other critical factors affecting osseointegration, namely, those related to the metabolism of bone tissues. The aim of this review is to shed light on the effects of implant-related factors, like implant surface or titanium particle release; surgical-related factors, like osseodensification or implanted biomaterials; various drugs, like selective serotonin reuptake inhibitors, proton pump inhibitors, anti-hypertensives, nonsteroidal anti-inflammatory medication, and statins, and host-related factors, like smoking, diet, and metabolic syndrome on bone metabolism, and aseptic peri-implant bone loss. Despite the infectious nature of peri-implant biological complications, these factors must be surveyed for the effective prevention and management of peri-implantitis.

In vitro and in vivo assessment of caprine origin Staphylococcus aureus ST398 strain UTCVM1 as an osteomyelitis pathogen

Staphylococcus aureus (SA) is a significant and well-recognized causative organism of bacterial osteomyelitis. Osteomyelitis is an inflammatory bone disease characterized by progressive bone destruction and loss. This disease causes significant morbidity and mortality to the patient and poses therapeutic challenges for clinicians. To improve the efficacy of therapeutic strategies to combat bacterial osteomyelitis, there is a need to define the molecular epidemiology of bacterial organisms more clearly and further the understanding of the pathogenesis of SA osteomyelitis. We conducted in vitro characterization of the pathogenic capabilities of an isolate of SA ST398 derived from a clinical case of osteomyelitis in a goat. We also report a rodent mandibular defect model to determine the ability of ST398 to cause reproducible osteomyelitis. Our results indicate that ST398 can invade and distort pre-osteoblastic cells in culture, induce significant inflammation and alter expression of osteoregulatory cytokines. We also demonstrate the ability of ST398 to induce osteomyelitis in a rat mandibular model. When compiled, these data support ST398 as a competent osteomyelitis pathogen.

Maxillary sinus floor augmentation comparing bovine versus porcine bone xenografts mixed with autogenous bone graft. A split-mouth randomized controlled trial

Aim

To compare the effectiveness of two xenografts for maxillary sinus floor augmentation in terms of clinical, radiographical, histologic, and molecular outcomes.

Materials and methods

A split‐mouth randomized clinical trial was conducted at the University of Granada. Ten consecutive patients in need of bilateral two‐staged maxillary sinus floor augmentation were included. Each patient received both biomaterials (porcine bone mineral and anorganic bovine bone), which were randomly assigned for bilateral sinus augmentation. The maxillary autogenous bone scraped from the sinus access window was mixed with each xenograft at a 20:80 ratio. After a healing period of 6 months, bone biopsies were collected with a trephine during the implant placement in the regenerated area. Histologic, histomorphometrical, immunohistochemical, and molecular outcomes were analyzed. Clinical and radiographical data throughout the treatment phases were also evaluated.

Results

The resulting anatomic features were similar between both groups. After six months of graft consolidation, the graft resorption rates were similar between both biomaterials. The histologic, histomorphometrical, and immunohistochemical results showed no statistical differences between groups.

Conclusion

Anorganic bovine bone and porcine bone mineral combined with maxillary autogenous cortical bone show similar biologic and radiologic features in terms of biomaterial resorption, osteoconduction, and osteogenesis when used for maxillary sinus floor augmentation.

The role of cortical perforations in allogeneic block grafting for lateral augmentation in maxilla: A randomized clinical trial

BACKGROUND

The need of decortication on the recipient site remains unclear for bone regeneration. To our knowledge, there are no human clinical trials that studied the influence of decortication on cancellous allogeneic block grafting.

PURPOSE

The aim of the present study is to evaluate the influence of perforating the cortex of the recipient site on cancellous allogeneic block graft integration and revascularization in the maxilla.

MATERIAL AND METHODS

Twenty-six patients referred for lateral bone augmentation were included in this clinical trial. Patients received freeze-dried bone allograft cancellous blocks obtained from the iliac crest; cortical perforations of the recipient bed were performed in the test group while in the control group it was left intact. After a 4-month healing period another surgery was performed to place dental implants, and a bone biopsy was collected using a trephine. All samples underwent micro-CT scans, and were processed for histomorphometric and immunohistochemical analysis. Implant survival comparisons were made using a repeated measures analysis of variance (ANOVA) while all other variables were compared using the analysis of covariance (ANCOVA).

RESULTS

One hundred and nineteen implants were placed into 110 augmented sites. One hundred percent implant survival rate was reported during 24 months follow-up period. No differences were reported in bleeding on probing at 1 (5.6 vs 9%) and 2 years (13.2 vs 12.1%), probing pocket depth at 1 (3.4 ± 0.95 vs 3.6 ± 1.12 mm) and 2 years (3.8 ± 1.02 vs 4.1 ± 1.46 mm), and marginal bone loss at 1 (0.2 ± 0.52 vs 0.3 ± 0.57 mm) and 2 years (0.6 ± 0.91 vs 0.5 ± 0.87 mm). No statistically significant differences were found in the micro-CT and histomorphometric analysis in terms of newly formed bone (25.7 ± 11.2% vs 22.3 ± 9.7%), soft tissue (33.0 ± 14.7% vs 36.5 ± 15.7%), remnant allograft (39.3 ± 20.4% vs 41.2 ± 22.7%), and bone mineralization (57.2 ± 10.6% vs 53.8 ± 8.7%). Perforating the cortex of the recipient site had no significant effect on angiogenesis as shown by immunohistochemical analysis of CD34 positive blood vessels (39.21 ± 10.53/mm² vs 34.16 ± 12.67/mm² ).

CONCLUSION

Cancellous allogeneic bone block grafts are a clinically acceptable alternative for horizontal bone augmentation. Cortical perforations of the recipient site in the maxilla did not improve angiogenesis nor bone formation within the block graft.

Evaluation of hard tissue 3-dimensional stability around single implants placed with guided bone regeneration in the anterior maxilla: A 3-year retrospective study

STATEMENT OF PROBLEM

Guided bone regeneration (GBR) is widely used to reconstruct peri-implant bone defects in the esthetic zone. However, the dimensional stability of this bone-biomaterial composite is not fully understood.

PURPOSE

The primary aim was to evaluate the hard tissue 3-dimensional (3D) stability around single implants placed with simultaneous GBR by using deproteinized bovine bone mineral (DBBM) in the anterior maxilla and explore possible influencing factors.

MATERIAL AND METHODS

The records of patients who had received implants in the anterior maxilla from January 2015 to March 2016 were reviewed retrospectively. The change in volume and thickness of the facial hard tissue were analyzed. To explore possible influencing factors, the thickness and surface area of facial graft were measured, and the time point at which implants were placed and the healing protocol were recorded. Secondary outcome measures were peri-implant marginal bone loss, bleeding on probing (BOP), and pink esthetic score (PES). Statistical analysis was conducted by using the Student t test, Mann-Whitney U test, Kruskal-Wallis test, or generalized estimating equation analysis (α=.05).

RESULTS

Fifty-five participants were included in this study, and no implants had been lost after 3 years. BOP was present in 10 (18.2%) participants. The mean ±standard deviation PES of all implants for this study was 11.0 ±2.1. The mean ±standard deviation percentage of residual hard tissue volume was 36.9 ±23.5%, with a significant difference found between time points before 9 months (P<.05). Type 3 implant placement (OR=1.449, P=.031) was found to have a higher percentage of residual hard tissue volume. A greater reduction of the facial hard tissue thickness was observed in participants with thicker postoperative facial grafting (OR=1.463, P=.001). No statistically significant difference was found between the facial, palatal, mesial, and distal peri-implant sites in terms of marginal bone loss (P>.05).

CONCLUSIONS

Although single-tooth implant placement combined with GBR using DBBM in the anterior maxilla offered satisfactory esthetic and functional outcomes after a 3-year follow-up, significant hard tissue volume and thickness reduction in grafted sites was detected, especially during the initial 9-month postoperative period. This phenomenon may be correlated with the timing of implant placement and the thickness of the facial graft.

Algae-derived hydroxyapatite behavior as bone biomaterial in comparison with anorganic bovine bone: A split-mouth clinical, radiological, and histologic randomized study in humans

OBJECTIVES

To analyze a modified biphasic phycogenic biomaterial in comparison with anorganic bovine bone in maxillary sinus floor elevation in humans.

MATERIAL AND METHODS

Eight male patients in need of bilateral two-stage sinus floor elevation were consecutively recruited for this randomized split-mouth study. A combination of autogenous cortical bone (ACB, 20%) and anorganic bovine bone (ABB, 80%) (ACB + ABB group) or ACB (20%) and modified biphasic phycogenic material (BP, 80%) (ACB + BP group) were randomly assigned to graft each sinus. Patients were followed up for 6 months post-surgery when bone samples were collected for analysis.

RESULTS

Radiographically, bone height gain was statistically higher in the ACB + ABB versus the ACB + BP group. While the analysis of the biological compartments showed differences in non-mineralized tissue (39.15 ± 20.97% vs. 65.87 ± 28.59%, ACB + ABB vs. ACB + BP respectively; p = .018) and remnant biomaterial particles (22.62 ± 17.01% vs. 7.96 ± 8.57%, respectively; p = .028), the percentage of mineralized tissue (38.23 ± 17.55% vs. 24.14 ± 24.66%, respectively; p = .398) showed no statistically significant difference. In contrast, ACB + ABB biopsies showed higher Musashi-1-positive cells per mm² compared to ACB + BP biopsies (811.49 ± 875.30 vs. 236.90 ± 280.81; p < .018), where the fusiform cells corresponded mainly with fibroblasts, as demonstrated by ultrastructural analysis.

CONCLUSION

Both combinations of materials exhibited bone formation after 6 months of healing in the maxillary sinus cavity. However, the combination with biphasic phycogenic biomaterial induced a higher radiographical vertical resorption and graft collapse in comparison with the combination with anorganic bovine bone, possibly due to a higher remodeling of the graft.

Biphasic hydroxyapatite and ß-tricalcium phosphate biomaterial behavior in a case series of maxillary sinus augmentation in humans

OBJECTIVES

The aim of this study was to evaluate and compare the morphometric components and the histological properties of pristine bone and bone grafted with a biphasic ß-tricalcium phosphate in humans using the maxillary sinus model. Reparative mesenchymal stem cells in the pristine bone and graft were also evaluated.

MATERIALS AND METHODS

For this prospective case series, sinus augmentation was performed using a biphasic ß-tricalcium phosphate. After 6 months of healing, a core of remnant native alveolar bone and grafted bone was collected with a trephine. Histological, histomorphometrical, and immunohistochemical techniques were performed. Radiological analysis through cone beam computerized tomography was also conducted.

RESULTS

A total of 10 patients were enrolled in this study. Radiologically, patients showed an average increase of crestal bone of 8.03 ± 1.72 mm. Morphologically, the grafted area was composed by 34.93 ± 14.68% of new mineralized tissue, 9.82 ± 11.42% of remnant biomaterial particles, and 55.23 ± 11.03% non-mineralized tissue. Histologically, we found no differences in the number of osteocytes per mm² (p = 0.674), osteoblasts (p = 0.893), and blood vessels (p = 0.894) in the grafted area compared to the pristine bone. Differences were found on the number of osteoclasts (15.57 ± 27.50 vs. 5.37 ± 16.12, p = 0.027). The number of Musashi-1 positive mesenchymal cells (239.61 ± 177.4 vs. 42.11 ± 52.82, p = 0.027) was also significantly higher in the grafted area than in the pristine bone.

CONCLUSION

Biphasic ß-tricalcium phosphate is a suitable biomaterial to be used in the formation of new bone in sinus floor elevation procedures in humans, not only from the histomorphometrical point of view, but also regarding the cellular and vascular quality of the regenerated bone.

Sinus floor elevation using particulate PLGA-coated biphasic calcium phosphate bone graft substitutes: A prospective histological and radiological study

BACKGROUND

Poly (lactic-co-glycolic acid) (PLGA) is widely used for the development of delivery systems for drugs and therapeutic biomolecules in tissue engineering applications. Particles of biphasic calcium phosphate can be covered by PLGA to change their manipulating characteristics.

PURPOSE

Aim of this study was to investigate the radiological and histomorphometric results of the use of PLGA-coated biphasic calcium phosphate granules in sinus floor elevation and to analyze the underlying molecular processes by immunohistochemical staining.

MATERIALS AND METHODS

A randomized clinical study was designed to include patients in need of sinus floor elevation. Patients were assigned to receive either PLGA-coated biphasic calcium phosphate particles (group I) or the equivalent but noncoated particles (group II). Cone beam computed tomography (CBCT) scans were performed before and 6 months after the procedure to assess the bone height gain. At the time of implant placement, bone core biopsies were obtained at the site of implant placement. Histological sections were subjected to histomorphometric and immunohistochemical evaluation of differentiation markers (Musashi-1 [MSI1]).

RESULTS

No statistically significant differences were observed between groups for the radiologic parameters. No differences were observed histologically or histomorphometrically. However, PLGA-coated particles (group I) were more colonized by MSI1-positive osteoblast precursors (P = 0.0001, chi-squared test) and were penetrated by more CD34-positive vascular structures (P = 0.001, chi-squared test) than noncoated particles (group II).

CONCLUSIONS

PLGA-coated particles are associated with more MSI11-positive cells and more extensive microvascularization than noncoated particles.

Composite Alloplastic Biomaterial vs. Autologous Platelet-Rich Fibrin in Ridge Preservation

AIM

The aim of this study was to examine the clinical and histological differences of using a combination of alloplastic beta triphasic calcium phosphate (β-TCP) and a cross-linked collagen membrane versus autologous platelet-rich fibrin (PRF-L) in ridge preservation after dental extraction.

MATERIAL AND METHODS

Fifty-one patients were included in this observational case-series study. Dental extractions were performed, after which 25 patients were grafted with β-TCP and 26 with PRF-L. After four months of healing, clinical, radiological, histomorphometric and histological evaluations were performed.

RESULTS

A significantly higher percentage of mineralized tissue was observed in samples from the PRF-L grafted areas. Cellularity was higher in PRF-L grafted areas (osteocytes in newly formed bone per mm² = 123.25 (5.12) vs. 84.02 (26.53) for PRF-L and β-TCP, respectively, p = 0.01). However, sockets grafted with PRF-L showed a higher reduction in the bucco-lingual dimension after four months of healing (2.19 (0.80) vs. 1.16 (0.55) mm, p < 0.001), as well as a higher alteration in the final position of the mid muco-gingival junction (1.73 (1.34) vs. 0.88 (0.88) mm, p < 0.01).

CONCLUSION

PRF-L concentrate accelerates wound healing in post-extraction sockets in terms of new mineralized tissue component. However, the use of β-TCP biomaterial appears to be superior to maintain bucco-lingual volume and the final position of the muco-gingival junction.

Pre-implantological bone formation in the floor of the maxillary sinus in a self-supporting space

INTRODUCTION

In edentulous patients the form and size of the maxillary sinus vary greatly. Therefore sinus floor augmentation is a standard procedure for implantological purposes. As the sinus membrane cannot be characterized as periosteum, various augmentation materials are used.

HYPOTHESIS

an artificially generated space underneath the sinus membrane in the floor of the sinus will lead to spontaneous callus forming and a stable bony consolidation without augmentation material.

METHODS

Ten edentulous patients with highly atrophic maxillae were selected. Augmentation of the sinus floor was carried out in a split-mouth study design: On one side a combination of autogenous and xenogenous bone was used, and on the contralateral side a sinus membrane elevation was performed without using any substitutes. After a 6-month interval bone specimens from the test regions were harvested during implant placement.

RESULTS

Clear histological evidence of new bone formation was found in all human bone specimens. An active de-novo bone formation process could be proven by the presence of Haversian systems (osteons) displaying osteoblastic and osteoclastic activity.

CONCLUSION

In the maxillary sinus of edentulous patients a spontaneous callus-derived de-novo bone formation is possible by elevating the sinus membrane without using augmentation materials.

β-TCP/HA with or without enamel matrix proteins for maxillary sinus floor augmentation: a histomorphometric analysis of human biopsies

BACKGROUND

It is still unclear whether enamel matrix proteins (EMD) as adjunct to bone grafting enhance bone healing. This study compared histomorphometrically maxillary sinus floor augmentation (MSFA) with β-TCP/HA in combination with or without EMD in humans.

METHODS

In ten systemically healthy patients needing bilateral MSFA, one side was randomly treated using β-TCP/HA mixed with EMD (BC + EMD) and the other side using only β-TCP/HA (BC). After 6 months, biopsies were harvested from grafted areas during implant installation, being histologically and histomorphometrically analyzed. Differences between the groups considering new bone formation, soft tissues, and remaining BC were statistically evaluated.

RESULTS

All patients showed uneventful healing after MSFA, and dental implant installation was possible in all patients after 6 months. Histological analysis showed newly formed bone that was primarily woven in nature; it was organized in thin trabeculae, and it was occasionally in contact with residual bone substitute particles, which appeared in various forms and sizes and in advanced stage of degradation. Mean bone area was 43.4% (CI95 38.9; 47.8) for the BC group and 43.0% (CI95 36.6; 49.5) for the BC + EMD group. Mean soft tissue area was 21.3% (CI95 16.5; 26.2) for BC group and 21.5% (CI95 17.7; 25.3) for BC + EMD group, while the remaining biomaterial was 35.3% (CI95 36.6; 49.5) and 35.5% (CI95 29.6; 41.3) for BC and BC + EMD group, respectively.

CONCLUSIONS

MSFA with BC resulted in adequate amounts of new bone formation allowing successful implant installation; adding EMD did not have a significant effect.

Histopathological comparison of healing after maxillary sinus augmentation using xenograft mixed with autogenous bone versus allograft mixed with autogenous bone

OBJECTIVE

To compare the clinical and histologic outcomes of two different grafting materials (allograft and xenograft) when combined with autogenous bone and covered with a collagen membrane for sinus augmentation.

MATERIAL AND METHODS

A parallel case series of fourteen patients in need of a unilateral sinus augmentation was evaluated in this study. Seven patients received a graft composed by autologous cortical bone (ACB) and anorganic bovine bone in a ratio of 1:1; the other seven patients received ACB mixed with an allograft in the same ratio. Bone biopsies were obtained 6 months after sinus augmentation at the time of implant placement. Comparative histomorphometrical, histopathological, and immunohistochemical analyses were conducted and statistically analyzed.

RESULTS

After 12 months of functional loading, all implants in both groups were clinical and radiographically successful. Histomorphometrically, although the initial bone formation was not significantly different between groups (new mineralized tissue: 41.03(12.87)% vs. 34.50(13.18)%, p = .620; allograft vs. xenograft groups), the graft resorbed faster in the allograft group (remnant graft particles: 9.83[7.77]% vs. 21.71[17.88]%; p = .026; allograft vs. xenograft groups). Non-mineralized tissue did not statistically differ either (49.00[14.32]% vs. 43.79[19.90]%; p = .710; allograft vs. xenograft groups). The histologic analyses revealed higher cellular content, four times more osteoid lines, and higher vascularization in the xenograft group. Musashi-1 (mesenchymal stromal cell marker) was also more intensively expressed in the xenograft group (p = .019).

CONCLUSIONS

Both composite grafts generate adequate substratum to receive dental implants after healing. Compared with the xenograft composite, allograft composite shows faster turnover and a quicker decrease in biological action after 6 months.

Prospective and Randomized Evaluation of ChronOS and Bio-Oss in Human Maxillary Sinuses: Histomorphometric and Immunohistochemical Assignment for Runx 2, Vascular Endothelial Growth Factor, and Osteocalcin

PURPOSE

The aim of this study was to compare ChronOS (β-tricalcium phosphate), Bio-Oss, and their addition to an autogenous bone graft in a 1:1 ratio in human maxillary sinus bone augmentation.

MATERIALS AND METHODS

Thirty maxillary sinuses were divided in 5 groups: group 1 included 6 maxillary sinuses grafted with autogenous bone graft alone; group 2 included 6 maxillary sinuses grafted with ChronOS; group 3 included 6 maxillary sinuses grafted with ChronOS and autogenous bone graft in a 1:1 ratio; group 4 included 6 maxillary sinuses grafted with Bio-Oss; and group 5 included 6 maxillary sinuses grafted with Bio-Oss and autogenous bone graft in a 1:1 ratio. The number of samples for each group was determined by the statistical power test.

RESULTS

The median areas of new bone formation in groups 1, 2, 3, 4, and 5 were 121,917.0, 83,787.0, 99,295.0, 65,717.0, and 56,230.0 μm², respectively. Statistically significant differences were found between groups 3 and 5, groups 1 and 4, and groups 1 and 5 (P < .05). The median areas of remaining biomaterial were 2,900.5, 5,291.0, 2,662.0, 56,258.5, and 64,753.5 μm² in groups 1, 2, 3, 4 and 5, respectively. Statistically significant differences occurred between groups 1 and 5, groups 3 and 5, and groups 2 and 5 (P < .05). Areas of connective tissue were 67,829.0 ± 22,984.6 μm² in group 1, 97,445.9 ± 18,983.3 μm² in group 2, 88,256.0 ± 21,820.5 μm² in group 3, 65,501.8 ± 6,297.6 in group 4, and 70,203.2 ± 13,421.3 μm² in group 5.

CONCLUSIONS

ChronOS combined with autogenous bone graft presented a behavior similar to that of autogenous bone graft alone. However, the groups treated with Bio-Oss showed immuno-labeling results indicating maturation of grafted bone.

Maxillary sinus grafting with autograft vs. fresh frozen allograft: a split-mouth histomorphometric study

BACKGROUND

Surgical techniques as sinus floor augmentation have made it possible to increase the bone volume of the posterior maxilla so that implant placement may be feasible. A large variety of bone grafting materials have been utilized for sinus floor augmentation. A good alternative is allograft. Fresh frozen bone is harvested from live or cadaveric donors and then immediately frozen and stored at -80 °C. To date, studies about the effect of fresh frozen bone are scarce.

OBJECTIVE

Evaluation of new bone formation, following maxillary sinus grafting with autograft vs. fresh frozen allograft.

MATERIALS AND METHODS

A split-mouth edentulous design including 15 patients was used. Sinus floor augmentation was carried out using either autogenous bone harvested from the ramus area or fresh frozen bone from allogeneic femoral heads. The choice was determined randomly, using a randomized table. The grafted sinus was left to heal for 6 months. Biopsies were harvested from the lateral wall. The biopsies were used for bone histology and histomorphometric analysis. After collection of the biopsy, dental implants were placed. After a healing period of 6 months, the implants were loaded.

RESULTS

Implant survival, histology, and histomorphometry of sinuses grafted with autogenous or fresh frozen bone were similar. The new bone formation took place predominantly around and in-between particles.

CONCLUSIONS

The findings of the present study support the use of fresh frozen bone allografts for sinus floor augmentation.

Anorganic bovine bone (ABB) vs. autologous bone (AB) plus ABB in maxillary sinus grafting. A prospective non-randomized clinical and histomorphometrical trial

OBJECTIVES

This investigation focused on histological characteristics and 5-year implant survival after sinus floor augmentation with anorganic bovine bone (ABB, Bio-Oss) and ABB plus autologous bone (AB) with a ratio of 1/1.

MATERIAL AND METHODS

Nineteen consecutive patients with bony atrophy of the posterior edentulous maxilla and a vertical bone height ≤4 mm were prospectively included in this study. In the first surgical stage, the maxillary sinus was non-randomized either augmented with ABB alone (n = 12) or a 1/1 mixture of ABB and AB (n = 7). After a mean healing period of 167 days, biopsies were harvested in the region of the grafted sinus with a trephine burr and implants were placed simultaneously, ABB n = 18 and ABB + AB n = 12. The samples were microradiographically and histomorphometrically analyzed judging the newly formed bone (bone volume, BV), residual bone substitute material volume (BSMV), and intertrabecular volume (soft tissue volume, ITV) in the region of the augmented maxillary sinus. Implant survival was retrospectively evaluated from patient's records.

RESULTS

No significant difference in residual bone substitute material (BSMV) in the ABB group (31.21 ± 7.74%) and the group with the mixture of ABB and AB (28.41 ± 8.43%) was histomorphologically determined. Concerning the de novo bone formation, also both groups showed statistically insignificant outcomes; ABB 26.02 ± 5.23% and ABB + AB 27.50 ± 6.31%. In all cases, implants were installed in the augmented sites with sufficient primary stability. After a mean time in function of 5 years and 2 months, implant survival was 93.75% in the ABB and 92.86% in the ABB + AB group with no statistically significant differences.

CONCLUSION

The usage of ABB plus AB to a 1/1 ratio leads to an amount of newly formed bone comparable with the solitary use of ABB after grafting of the maxillary sinus. Considering that ABB is a non-resorbable bone substitute, it can be hypothesized that this leads to stable bone over time and long-term implant success. Importantly, in the sole use of ABB, bone grafting and therefore donor site morbidities can be avoided.

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.

Morphological evidences of Bio-Oss® colonization by CD44-positive cells

OBJECTIVES

Our objectives were to examine vascular and cellular colonization in anorganic bovine bone (ABB) after 6 months of healing in human maxillary sinus augmentation grafts.

MATERIAL AND METHODS

Fifty unilateral maxillary sinus augmentation procedures were performed on 50 consecutive patients. Bone cores were obtained through the implant receptor sites 6 months later and evaluated with morphological image analysis and immunohistochemical techniques.

RESULTS

Image analysis revealed a mean of 35.44 ± 16% vital bone, 31.66 ± 15% non-mineralized tissue, and 32.72 ± 25% remnant ABB particles. In our patients, neovascularization in 46.3% of cases was demonstrated within ABB particles 6 months after sinus floor augmentation surgery. Neovascularization of ABB particles was inversely related to age, directly to osteoclast number per mm², and not influenced by habits or disease. CD44-positive cells colonization was found in 74% of cases. An important correlation was found regarding CD44 expression and number of vessel in ABB particles (r = 0.624 P < 0.001, Pearson). Osteopontin expression was detected on the interstitial boundary of bone with ABB particles and within the osteocyte lacunae and bone canaliculi and was relationship with presence of CD44-positive cells inside ABB particles (r = 0.388, P = 0.046, Pearson).

CONCLUSION

In conclusion, images compatible with osteone colonized by osteocytes CD44 positive and neovascularization in ABB particles were observed after 6 months of graft maturation. These biologic events have not previously been morphologically and immunohistochemically documented.

Histomorphometrical evaluation of fresh frozen bone allografts for alveolar bone reconstruction: preliminary cases comparing femoral head with iliac crest grafts

PURPOSE

In the past few years, the use of fresh frozen bone (FFB) grafts has significantly increased. The aim of this study was to evaluate the reconstruction of alveolar bone using femoral head and iliac crest FFB grafts.

MATERIALS AND METHODS

The study included 10 patients who need endosseous implant insertion in severe atrophic maxillae. The patients were treated with FFB grafts collected from the femoral head or iliac crest. Bone regeneration was evaluated 6 months after surgery by macroscopic and microscopic analyses.

RESULTS

Our results showed good regenerative capacity, both with the FFB from the femoral head and iliac crest. In particular, similar percentages of new-bone formation and graft residual were observed, whereas differences between the percentage of total bone (higher for the iliac crest) and the percentage of non-mineralized tissue (higher for the femoral head) were present. A significantly higher percentage of CD34-positive vessels in the FFB allograft from the femoral head than in the iliac crest were observed.

CONCLUSIONS

These findings suggest that FFB allografts could represent a reliable option in oral and maxillofacial surgery. Nevertheless, differences between the use of femoral head or iliac crest bone allografts linked with their different structures should be considered for a more effective surgery.