S-nitroso albumin enhances bone formation in a rabbit calvaria model

Nitric oxide (NO) is a mediator involved in bone regeneration. We therefore examined the effect of the novel NO donor, S-nitroso human serum albumin (S-NO-HSA) on bone formation in a rabbit calvaria augmentation model.Circular grooves (8 mm diameter, two per animal) were created by a trephine drill in the cortical bone of 40 rabbits and titanium caps were placed on the rabbit calvaria bone filled with a collagen sponge soaked with either 100 μL S-NO-HSA (5%, 20%) or human albumin (5%, 20%). After 4 weeks the titanium hemispheres were subjected to histological and histomorphometric analysis. Bone formation and the volume of the residual collagen sponge were evaluated.S-NO-HSA treatment groups had a significantly higher volume of newly formed bone underneath the titanium hemispheres compared to the albumin control groups (5%: 15.5 ± 4.0% versus 10.6 ± 2.9%; P < 0.05; 20%: 14.0 ± 4.6% versus 6.0 ± 3.8%; P < 0.01). The volume of residual collagen sponge was also significantly lower in the S-NO-HSA groups compared to the control groups (5%: 0.4 ± 0.5% versus 2.6 ± 2.4%; P < 0.05 and 20%: 1.5 ± 2.7% versus 13.0 ± 18.7%; P < 0.01).This study demonstrates for the first time that S-NO-HSA promotes bone formation by slow NO release. Additionally, S-NO-HSA increases collagen sponge degradation.     

Enhanced ridge preservation by bone mineral bound with collagen-binding synthetic oligopeptide: a clinical and histologic study in humans

Background: The ridge‐preservation technique has been applied with membrane alone or membrane plus graft. Synthetic peptides, mimicking bioactive growth factor or extracellular matrix protein, have been attempted to provide an active surface of the biomaterials in inducing bone formation while alleviating the limitations of whole protein such as short half‐life, immunologic responses. The aim of the present clinical study is to examine the osteogenic effect of synthetic oligopeptide–coated bone mineral compared to bone graft without peptide when applied with collagen membrane in a ridge‐preservation technique. Methods: Synthetic oligopeptide from the collagen‐binding domain of osteopontin was chemically synthesized and coated onto the surface of bone mineral particulates. Ridge preservations were performed at 44 extraction sites in 42 patients (20 males and 22 females). Analyses of clinical parameters and histomorphometric evaluations were conducted to compare the osteogenic effects of the grafts between baseline and 6 months. Results: In the bone grafts of the control group treated without synthetic peptide, new bone formation was only seen around borders and basal areas. However, new bone was observed broadly in the defects of the test group treated with synthetic peptide–coated bone mineral, as seen not only at peripheries but also in the central and coronal parts of bone cores in the defects. The average percentage of new bone formation was significantly higher in the test group (5.3% ± 8.3% versus 10.4% ± 4.6%). The contact percentages between the graft particles and the new bone were 8.2% ± 11.3% for the control group and 20.4% ± 7.5% for the test group (P <0.05). Conclusions: The ridge‐preservation approach using synthetic oligopeptide–coated bone mineral with collagen membrane effectively prevented the resorption of hard tissue with higher bone‐to‐graft contact, and the oligopeptide‐coated bone may be a choice for ridge‐preservation procedures while assuring new bone formation.     

Efficacy of doxycycline release collagen membrane on surgically created and contaminated defects in rat tibiae: A histopathological and microbiological study

BackgroundThe effects of systemic antibiotics on controlling infective pathogens after guided bone regeneration(GBR) procedures especially in membrane exposures are limited. However, local administrations of antibiotics are rare in GBR techniques.AimThe aim of this study was to investigate the osteogenesis potential and the antibacterial effect of a doxycycline releasing collagen membrane in surgically created and contaminated defects in rat tibiae.Material and methodsDefects were created in 20 rats that were randomly divided in to two groups: control group (defect contaminated by Porphyromonas gingivalis, filled with bone graft and covered by collagen membrane); test group (defect contaminated by P. gingivalis filled with bone graft and covered by collagen membrane containing 1 mg/cm² doxycycline. Animals were sacrificed post surgically on the 14th day for microbiologic evaluation and on the 28th day for histopathological evaluation.ResultsThe degree of osteogenesis in the test group was seen to be significantly higher than control group (p: 0.011; p < 0.05). Furthermore in test group, no bacterial growth was observed. The bacteria counts were determined between 1 × 104 and 268 × 104 CFU/g with a median of 1.32 × 104 for control group.ConclusionsWithin the limitations of this study, the results of the present study suggests that the use of a doxycycline releasing membrane has a positive effect on contaminated GBR procedures for limiting P. gingivalis infections leading to bone formation following GBR procedures in a rat model.     

Staged horizontal bone augmentation for dental implants in aesthetic zones: A prospective randomized controlled clinical trial comparing a half-columnar bone block harvested from the ramus versus a rectangular bone block from the symphysis

In this study, the clinical outcomes of horizontal ridge augmentation using half-columnar bone grafts from the ramus (group I: 27 patients, 32 implants) versus rectangular bone grafts from the symphysis (group II: 19 patients, 27 implants) were compared; grafts were combined with organic bovine bone and collagen membrane. Cone beam computed tomography images were obtained preoperatively, immediately after restoration (baseline), and 1 year after loading. Four months after grafting, horizontal bone resorption at the alveolar crest did not differ significantly between the two groups (P = 0.291). At 4 mm apical to the alveolar crest, horizontal bone resorption in group I was significantly less than that in group II (P = 0.041). One year after loading, horizontal bone resorption in group I was lower than that in group II, with no significant difference. The residual thickness of the labial bone at the implant site in group I was significantly higher than that in group II. Horizontal ridge augmentation with either a half-columnar autogenous graft from the ramus or a rectangular autogenous graft from the symphysis can provide acceptable results in aesthetic regions. The half-columnar group demonstrated better graft stability both at 4 months after augmentation and 1 year after loading.     

Radiographic outcomes of lateral sinus floor elevation with and without bone window repositioning: one-year results of a randomized controlled trial

The objective of this study was to perform a comparative evaluation of the radiographic outcomes of lateral sinus floor elevation with and without bone window repositioning (BLSFE and LSFE, respectively) when applied concomitantly with implant placement. A randomized controlled clinical trial was conducted between February 1, 2016 and May 1, 2017 including 26 individuals with at least one missing tooth. Participants were randomized 1:1 to undergo BLSFE (10 participants, 16 implants) or LSFE (13 participants, 19 implants). Bovine-derived xenograft was used in both groups and the implants were inserted concomitantly. In the BLSFE group, the antrostomy was covered with a repositioned bone window and then with a concentrated growth factors (CGF) membrane. In the LSFE group, the antrostomy was covered with a CGF membrane. Panoramic radiographs were taken before surgery (T0), immediately postoperative (T1), and at 12 months postoperative (6 months after loading) (T2). Marginal bone loss (MBL), apical bone gain, augmented alveolar bone height, and intra-sinus bone augmentation were evaluated on panoramic radiographs at T2. A linear regression analysis with generalized estimating equation models was performed. The implant survival rate was 100% at 1 year after implant surgery. The residual alveolar bone height at T0 was comparable in the BLSFE and LSFE groups (3.58 ± 1.49 mm vs 4.12 ± 1.61, P = 0.32), as was the alveolar bone height at T1 (13.61 ± 1.82 mm vs 12.38 ± 1.82 mm, P = 0.06). At T2_, significantly higher alveolar bone height, intra-sinus bone augmentation, and apical bone gain, and lower distal MBL were observed in the BLSFE group when compared to the LSFE group, with adjusting for covariates (β = 2.44, 95% CI 1.42–3.46, P < 0.0001; β = 2.38, 95% CI 1.35–3.41, P < 0.0001; β = 2.33, 95% CI 1.23–3.42, P < 0.0001; and β = ?0.43, 95% CI ?0.83 to ?0.02, P = 0.038, respectively). No significant difference was observed for mesial MBL or apical bone resorption at T2. Lateral sinus floor elevation with bone window repositioning may result in higher bone augmentation after 1 year than the traditional approach. Further research is needed to elucidate the effect of lateral sinus floor elevation with bone window repositioning.     

Simultaneous sinus membrane elevation and dental implant placement without bone graft: a 6-month follow-up study

Background: Previous studies have shown that simultaneous elevation of the sinus mucosal lining and placement of dental implants without graft materials can be a predictable procedure. Nevertheless, few prospective, controlled, and randomized studies have evaluated this technique. The aim of this prospective, controlled, and randomized clinical study is to evaluate whether sinus membrane elevation and simultaneous placement of dental implants without autogenous bone graft can create sufficient bone support to allow implant success 6 months post‐surgically. Methods: Sinus membrane elevation and simultaneous placement of dental implants were performed bilaterally in 15 patients in a split‐mouth design. The sinuses were assigned to two groups: the test group, with simultaneous sinus mucosal lining elevation and placement of dental implants without graft materials; and the control group, with simultaneous sinus mucosal lining elevation and placement of dental implants with intraoral autogenous bone graft. After 6 months of healing, abutments were connected. For each implant, length of implant protrusion into the sinus, resonance frequency analysis, and bone gain were recorded at baseline and 6 months follow‐up. Results: Clinical complications were not observed, except for two postoperative fistulas and suppuration in both groups. Only one implant of the test group was lost, reaching a success rate of 96.4% and 100% for the test and control groups, respectively. After healing, radiographic new peri‐implant bone was observed in both groups ranging between 8.3 ± 2.6 and 7.9 ± 3.6 mm for the control and test groups, respectively (P >0.05). Resonance frequency analysis values were lower for the control group compared to baseline (P <0.05). However, these values were similar at 6 months (P >0.05). A significant positive correlation was found between the protruded implant length/bone gain and implant survival/sinusitis (P <0.0001). Conclusion: Implants placed simultaneously to sinus membrane elevation without graft material resulted in bone formation over a period of 6 months.     

Evaluation of bone gain in horizontal ridge augmentation using titanium mesh in combination with different flap advancement techniques: a randomized clinical trial

The aim of this study was to investigate and compare the clinical and radiographic bone gain in guided bone regeneration with titanium mesh, for four different advancement techniques: periosteal releasing incision (PRI), double flap incision (DFI), modified periosteal releasing incision (MPRI), and coronally advanced lingual flap (CALF). Forty patients with a partially edentulous mandible were allocated randomly to four study groups (PRI, DFI, MPRI, CALF; 10 patients in each). Clinical bone gain (primary outcome) and radiographic bone gain were evaluated. In addition, correlations between study variables (clinical and radiographic bone gain, flap advancement, mesh exposure area and percentage exposure, pain, and swelling) were explored. CALF exhibited the highest mean clinical bone gain (4.12 ± 1.37 mm) and PRI the lowest (2.60 ± 1.36 mm); the mean clinical bone gain differed significantly among the groups (P < 0.001). The highest mean radiographic bone gain was seen in the CALF group (3.54 ± 1.65 mm) and the lowest in the PRI group (2.06 ± 1.11 mm); the mean radiographic bone gain also differed significantly among the groups (P < 0.001). The correlation analysis revealed positive correlations between flap advancement and radiographic bone gain (P = 0.003) and between swelling and pain (P = 0.007). An inverse correlation was found between flap advancement and swelling (P = 0.049), mesh exposure area and clinical bone gain (P = 0.022), and mesh exposure percentage and clinical bone gain (P = 0.017). In summary, the highest clinical and radiographic bone gain was observed for CALF, while the lowest was observed for PRI.     

Ridge Preservation Comparing Socket Allograft Alone to Socket Allograft Plus Facial Overlay Xenograft: A Clinical and Histologic Study in Humans

Background: Previous studies of ridge preservation showed a loss of ≈18% or 1.5 mm of crestal ridge width in spite of treatment. The primary aim of this randomized, controlled, masked clinical trial is to compare a socket graft to the same treatment plus a buccal overlay graft, both with a polylactide membrane, to determine if loss of ridge width can be prevented by use of an overlay graft. Methods: Twelve patients who served as positive controls received an intrasocket mineralized cancellous allograft (socket group), and 12 patients received the same socket graft procedure plus buccal overlay cancellous xenograft (overlay group). Horizontal ridge dimensions were measured with a digital caliper, and vertical ridge changes were measured from a stent. Before implant placement, at 4 months, a trephine core was obtained for histologic analysis. Results: The mean horizontal ridge width at the crest for the socket group decreased from 8.7 ± 1.0 to 7.1 ± 1.5 mm for a mean loss of 1.6 ± 0.8 mm (P <0.05), whereas the same measurement for the overlay group decreased from 8.4 ± 1.4 to 8.1 ± 1.4 mm for a mean loss of 0.3 ± 0.9 mm (P >0.05). The overlay group was significantly different from the socket group (P <0.05). Histologic analysis revealed that the socket group had 35% ± 16% vital bone, and the overlay group had 40% ± 16% (P >0.05). Conclusions: The overlay treatment significantly prevented loss of ridge width and preserved or augmented the buccal contour. The socket and overlay groups healed with a high percentage of vital bone.     

Extraction socket preservation graft before implant placement with calcium sulfate hemihydrate and platelet-rich plasma: a clinical and histomorphometric study in humans

Background: The aim of this investigation is to evaluate clinical and histologic outcome of using medical‐grade calcium sulfate hemihydrate (MGCSH) mixed with platelet‐rich plasma (PRP) for extraction socket preservation graft before implant placement. Methods: This study is a single‐site, randomized and controlled investigation. Sixteen patients with a non‐restorable tooth requiring extraction followed by implant placement were enrolled in this study. After extraction of a tooth, eight selected patients randomly received MGCSH mixed with PRP in the extraction sockets (test group), and eight selected patients randomly received collagen resorbable plug dressing material (control group). At the time of extraction and 3 months later (at implant placement surgery), vertical and horizontal socket dimensions were measured. Bone core samples were retrieved from the center of the healed socket before implant placement for histomorphometric analysis. Results: There was a statistically significant difference between the two groups based on histomorphometric analysis (P <0.05). New vital bone percentage regenerated after 3 months of healing was 66.5% ± 10.4% in sockets grafted with MGCSH mixed with PRP compared to 38.3% ± 9.3% collagen resorbable plug. There was no statistically significant difference in the amount of vertical and horizontal bone resorption (P >0.05) between groups. In all cases but two in the control group, implants were placed with primary stability. Conclusion: MGCSH mixed with PRP showed greater vital bone volume at 3 months with rapid enhancement of bone healing compared to PRP‐free collagen resorbable graft.     

Clinical comparison of a xenogeneic collagen matrix versus subepithelial autogenous connective tissue graft for augmentation of soft tissue around implants

Dental implant placement is a predictable therapy for replacing teeth. Nevertheless, mechanical, biological, and aesthetic complications frequently occur. The aim of this study was to compare the clinical outcomes of a xenogeneic collagen matrix (XCM) used at the time of implant placement as an alternative to a subepithelial connective tissue graft (SCTG), for soft tissue augmentation. This was a prospective clinical trial with 12 months of follow-up. In the control group, soft tissue augmentation at the time of implant placement was performed with a SCTG, while in the test group, a XCM was employed. At 12 months postoperative, all xenografts showed no postoperative complications. In both groups, a significantly greater thickness was observed on the buccal and occlusal sides from preoperative to 3 months postoperative (P < 0.05). No statistically significant difference in pink aesthetic score (P = 0.379, 6 months postoperative) or marginal bone loss (P = 0.449 at 3 months postoperative, P = 0.778 at 6 months postoperative) was observed between the groups. Statistically significant differences in pain perceived by the patients (P < 0.0001) and the time to complete the surgical procedure (P = 0.0008) were detected. At 12 months after surgery, XCM provided similar clinical results in terms of soft tissue augmentation on the buccal and occlusal sides as compared with the SCTG.     

Bone regeneration after topical BMP-2-gene delivery in circumferential peri-implant bone defects

Objectives: The aims of this study were to evaluate the rate of bone formation and osseointegration after topical gene delivery with a liposomal vector system carrying bone morphogenetic protein (BMP)‐2 cDNA in combination with a collagen carrier and autologous bone as a carrier in freshly created peri‐implant bone defects. Materials and methods: Eight domestic pigs received nine calvariae defects each (10 × 7 mm). A dental implant was inserted into the centre of each defect. In the test groups, the remaining space was filled with the liposomal vector/BMP‐2 complex combined with a collagen carrier (n=18) or an autologous bone graft (n=18). Control groups were collagen only (n=18) and autologous bone graft only (n=18). Results: There was a significant difference in mineralisation rate in the BMP‐2/bone graft (29.9%± 4.8 and 68.3%± 7.2) and bone graft only (22.6%± 2.6 and 49.4%± 13.9) groups after 7 and 28 days. Mineralisation values were also significantly higher in the BMP‐2/collagen group (21.2%± 16.2 and 53.1%± 12.5) compared with the collagen‐only group (8.2%± 7 and 41%± 8.1) in two different regions after 28 days. Also the bone‐to‐implant contact was significantly increased in the BMP‐2/bone graft group after 28 days and in the BMP‐2/collagen group after 7 and 28 days compared with their control groups. Conclusions: The results of this study show a significantly positive effect of liposomal vector/BMP‐2 on bone regeneration and osseointegration in bony circumferential peri‐implant defects.     

Comparison of procedures for immediate reconstruction of large osseous defects resulting from removal of a single tooth to prepare for insertion of an endosseous implant after healing

This study evaluated the treatment outcome of immediate reconstruction of 45 large osseous defects resulting from removal of a single tooth with a 1:2 mixture of Bio-Oss^® and autologous tuberosity bone, and three different procedures for soft tissue closing (Bio-Gide^® membrane, connective tissue graft, full-thickness palatal mucosa graft; n = 15 per group). All defects had an unfavourable osseous–gingival relationship and vertical bone loss of >5 mm. The hard and soft tissues were immediately reconstructed after removal of the tooth. Implants were inserted after 3 months. Patients’ acceptance, complications and postoperative morbidity were prospectively evaluated by standardized clinical and radiographic examinations up to 12 months after the augmentation procedure. The patients completed a questionnaire on subjective complaints related to the procedure. All hard–soft tissue procedures resulted in sufficient bone volume for the insertion of implants and a favourable aesthetic outcome. The gingival mid-buccal aesthetics before, and 1 year after, treatment significantly favoured the full-thickness palatal mucosa graft, showing a gain in gingival contour of 0.5 ± 0.8 mm; the other procedures resulted in a 1.2 ± 1.6 mm decrease. Of the procedures evaluated, a full-thickness palatal mucosa graft was the most predictable for immediate reconstruction of the socket after tooth removal.     

Role of Space Provision in Regeneration of Localized Two‐Wall Intrabony Defects Using Periosteal Pedicle Graft as an Autogenous Guided Tissue Membrane

Background: Marginal pedicle periosteum (MPP) has been used as a rigid membrane in guided tissue regeneration (GTR) for osseous defects. The present study aims to study the effect of space provision by an alloplastic graft material in bone defect area (BDA) reduction of 2‐wall defects. Methods: Twenty interproximal intrabony 2‐wall defects in healthy non‐smoking patients with chronic periodontitis were randomly divided in control (group 1, periosteum alone) and experimental (group 2, periosteum with alloplastic graft material) groups. Measurements of probing depth (PD), clinical attachment level (CAL), and radiographic BDA were done at the baseline and 6‐month postoperative evaluations. Results: The 6‐month postoperative assessment showed clinical and radiographic improvements with PD reduction, CAL gain, and changes in BDA in both groups, which was statistically significant compared with baseline (P <0.05). However, BDA reduction was statistically greater in group 2 (48.88% ± 18.61%) compared with group 1 (14.08% ± 12.97%) at the 6‐month follow‐up (P = 0.009). Conclusion: Within the limitations of this study, it can be concluded that space provision by an alloplastic graft material increases the regenerative potential of MPP as a GTR membrane and results in increased defect fill.     

Comparative study of the osseous healing process following three different techniques of bone augmentation in the mandible: an experimental study

The aim of this study was to evaluate the osseointegration of three different bone grafting techniques. Forty-eight mature New Zealand rabbits were divided randomly into three groups of 16 each. Horizontal augmentation was performed on the corpus of the mandible using three different techniques: free bone graft (FBG), free periosteal bone graft (PBG), pedicled bone flap (BF). The animals were sacrificed at postoperative weeks 1, 3, or 8. Specimens were decalcified for histological examination, and histomorphometric measurements were performed. The histological evaluation demonstrated bony fusion between the grafts and the augmented mandibular bone after 8 weeks in all groups. At week 8, the bone volume was significantly greater in the BF group than in the FBG (P < 0.001) and PBG (P = 0.001) groups, and also the trabecular thickness was significantly greater than in the FBG (P = 0.015) and PBG (P = 0.015) groups. Trabecular separation was significantly lower in the BF group than in the FBG group at week 8 (P = 0.015). BF demonstrated greater osseous healing capacity compared to FBG and PBG. The preserved vascularization in BF improves the bone quality in mandibular bone augmentations.     

Comparable efficacy of silk fibroin with the collagen membranes for guided bone regeneration in rat calvarial defects

PURPOSE

Silk fibroin (SF) is a new degradable barrier membrane for guided bone regeneration (GBR) that can reduce the risk of pathogen transmission and the high costs associated with the use of collagen membranes. This study compared the efficacy of SF membranes on GBR with collagen membranes (Bio-Gide®) using a rat calvarial defect model.

MATERIALS AND METHODS

Thirty-six male Sprague Dawley rats with two 5 mm-sized circular defects in the calvarial bone were prepared (n=72). The study groups were divided into a control group (no membrane) and two experimental groups (SF membrane and Bio-Gide®). Each group of 24 samples was subdivided at 2, 4, and 8 weeks after implantation. New bone formation was evaluated using microcomputerized tomography and histological examination.

RESULTS

Bone regeneration was observed in the SF and Bio-Gide®-treated groups to a greater extent than in the control group (mean volume of new bone was 5.49 ± 1.48 mm³ at 8 weeks). There were different patterns of bone regeneration between the SF membrane and the Bio-Gide® samples. However, the absolute volume of new bone in the SF membrane-treated group was not significantly different from that in the collagen membrane-treated group at 8 weeks (8.75 ± 0.80 vs. 8.47 ± 0.75 mm³, respectively, P=.592).

CONCLUSION

SF membranes successfully enhanced comparable volumes of bone regeneration in calvarial bone defects compared with collagen membranes. Considering the lower cost and lesser risk of infectious transmission from animal tissue, SF membranes are a viable alternative to collagen membranes for GBR.     

Histological evaluation of the healing process of autografted mandibular bone defects in rats under treatment with zoledronate

ObjectiveThis study aims to evaluate the healing process of autografted mandibular bone defects in rats treated with zoledronate (ZOL).Subjects and methodsA total of 180 Wistar rats were divided into four groups: group L received intravenous infusion of two doses of 0.06 mg/kg ZOL, nine weeks apart; group H received 0.06 mg/kg ZOL, while groups C and NC received normal saline at three-week intervals for nine weeks. Three weeks following the last infusion, a unilateral mandibular bone defect (5 mm) was created. Except in the NC group, all defects were repaired with autologous iliac bone graft. Fifteen animals from each group were sacrificed on postoperative Day 20, Day 40, and Day 60. Graft healing was scored using a histological grading system (ranging from 1 to 6).ResultsHistological evaluations performed on postoperative Day 60 showed that the mandibular defects were mainly repaired with fibrous tissue in the NC and H groups (93.00% ± 7.51% and 82.67% ± 13.08%, respectively) and with bone in the C and L groups (75.33% ± 14.20% and 92.67% ± 8.84%, respectively). The percentage of fibrous tissue and bone as well as the healing score of the NC and H groups were significantly different (P = 0.001) from those of the C and L groups. However, these were not different between neither the NC and H groups nor the C and L groups.ConclusionBased on the results of the present study the hypothesis can be established that there also might be a dose-dependent effect of ZOL on the healing of bone grafts in humans. This hypothesis has to be verified or rejected in clinical trials.     

Osteogenic potential of calcium silicate-doped iron oxide nanoparticles versus calcium silicate for reconstruction of critical-sized mandibular defects: An experimental study in dog model

ObjectiveTo evaluate bioactivity and osteogenic potential of calcium silicate (CS)-doped iron oxide (Fe₂O₃) nanoparticles versus pure CS in the reconstruction of induced critical-sized mandibular defects.DesignCS-doped Fe₂O₃ was prepared; morphological and microstructure identification of nanoparticles were made. An in vivo randomised design was developed on 24 adult male dogs where four critical-sized mandibular defects were created in each dog. Bone defects were allocated into control, CS, CS-3% Fe₂O₃ and CS-10% Fe₂O₃ group. Dogs were euthanized at 1 and 3 months (12 dog/time) for histopathologic and histomorphometric evaluation.ResultsAt three months, bone formation and maturation were evident where mean ± SD percent of mature bone was 2.66 ± 1.8, 9.9 ± 2.5, 22.9 ± 4.9, and 38.6 ± 8.1 in control, CS, CS-3% Fe₂O₃, and CS-10% Fe₂O₃ groups respectively. A high significant (P < 0.001) increase in area percent of mature bone was recorded in CS, CS-3% Fe₂O₃, and CS- 10% Fe₂O₃ groups compared to control group (73%, 88% and 93.3% respectively). Significant increase (P < 0.001) in area of mature bone was recorded in CS-3% Fe₂O₃ and CS-10% Fe₂O₃ groups compared to CS group. A significant increase (P < 0.001) in area of mature bone formation was detected in CS-10% Fe₂O₃ group compared to other groups.ConclusionCS-doped Fe₂O₃ has good osteoconductive, biocompatible properties with promoted bone regeneration. Fe₂O₃ has synergistic effect in combination with CS to promote bone formation. Increasing concentration of Fe₂O₃ nanoparticles resulted in improved osteogenesis and maturation. Results suggests that the novel CS-Fe₂O₃ alloplasts could be used for reconstruction of critical-sized bone defects.     

Histologic and histomorphometric results of three bone graft substitutes after sinus augmentation in humans

The aim of this study was to compare the histological behavior of three bone graft materials placed in human. The comparison was made among Bio-Oss? (BO), Engipore? (EP), and PepGen P-15? (P-15). Five biopsies for each group of biomaterial, retrieved 6 months after sinus lift augmentation, were analyzed. The investigation was carried out using light microscope (LM), scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS), and circularly polarized light microscope (CPLM). Under LM, the amount of newly formed bone was significantly higher in BO than P-15 (P < .05), while the amount of residual graft material was significantly higher in P-15 than BO (P < .05). The extension of marrow spaces was significantly higher in EP than both BO and P-15 (P < .05). SEM-EDS analysis showed a Ca/P ratio of 1.8 for BO, 2.2 for EP, and 1.5 for P-15. Under CPLM, BO showed no significant difference for transverse (18.4 ± 2.7%) and longitudinal (16.3 ± 1.8%) bone collagen fibers (P = .195); EP showed a significant difference between transverse (4 ± 0.7%) and longitudinal (7.6 ± 2.5%) bone collagen fibers (P = .015); finally, P-15 showed no significant difference for transverse (3.8 ± 1.6%) and longitudinal (4.9 ± 1.2%) bone collagen fibers (P = .279). No investigated biomaterial was completely resorbed, but all the residual particles demonstrated a close bone integration to form a hybrid tissue. BO particles appeared perfectly osseointegrated in the trabecular bone. EP showed a tendency to concentrate the bone apposition into the microporosities; P-15 particles appeared bridged by newly formed bone trabeculae.     

Demineralization of the Contacting Surfaces in Autologous Onlay Bone Grafts Improves Bone Formation and Bone Consolidation

Background: Autologous bone grafts are usually well consolidated after 4 to 5 months but can be incompletely interlocked with the native bone. This study investigated the effect of acid demineralization of the graft–bed interface on graft consolidation. Methods: Onlay bone grafts were performed on the calvaria of 36 guinea pigs. Half of the animals had the graft–bed contacting surfaces demineralized with 50% citric acid (pH 1.0) for 3 minutes (test group). The other half received no demineralization (control group). The bone grafts were immobilized by a resorbable membrane glued to the recipient bed with cyanoacrylate. After 7, 30, and 90 days, specimens (n = 6) were obtained for light microscopy. Data from qualitative analysis and computerized histomorphometry were statistically processed at a significance level of 5%. Results: Osteogenesis was not seen at the interface after 7 days. After 30 days, the test group showed 34.39% ± 13.4% of the interface area filled with mineralized tissue, compared to 17.14% ± 8.6% in the control group (P = 0.026). After 90 days, the mean percentages of mineralized tissue at the interface in the test and control specimens were 54.00% ± 11.23% and 38.65% ± 7.76% (P = 0.041), respectively. Within groups, a higher percentage of the area filled with mineralized tissue was seen at 90 days compared to 30 days (P = 0.004 for control and 0.041 for test). Conclusions: Demineralization of the contacting surfaces between autologous bone graft and bone bed improved new bone formation and bone consolidation. These data need to be confirmed in humans.     

Efficacy of tissue engineered bone grafts containing mesenchymal stromal cells for cleft alveolar osteoplasty in a rat model

The development of sufficient tissue engineered bone grafts for alveolar cleft osteoplasty could reduce the necessity of autogenous bone grafts and its donor site morbidity. The aim of the study was to evaluate tissue engineered bone grafts in an artificially created bone defect.Bone grafts were created in vitro colonizing a synthetic hydroxyapatite–tricalciumphosphate scaffold (BONITmatrix^®) with either undifferentiated mesenchymal stromal cells (group 1) or osteogenic differentiated mesenchymal stromal cells (group 2). Cells were multiplied from bone marrow of donor rats. Unmodified scaffolds (group 3) and the tissue engineered bone grafts were inserted into artificial maxillary defects of 54 Lewis rats. In 18 animals the defects remained unfilled (control). After one, three and six weeks the rats were sacrificed. The defect was evaluated radiologically and histologically with regard to the remaining defect volume and diameter. Statistical analysis followed.The bone grafts led to a specific bone formation at the defect margin. No complete reunion of any defect was observed within the healing time. After six weeks, the remaining defect volume was 6.86 ± 3.21 mm³ (control), 4.08 ± 1.36 mm³ (group 1), 5.00 ± 0.84 mm³ (group 2) 5.50 ± 1.05 mm³ (group 3). The remaining defect diameter measured 2.63 ± 0.52 mm (control), 2.39 ± 0.23 mm (group 1), 2.53 ± 0.22 mm (group 2) and 2.70 ± 0.66 mm (group 3). In all experimental groups the defect volume and diameter decreased over time, which was significant for group 1 (p = 0.014), group 2 (p = 0.025) and group 3 (p = 0.048). The defect volume and width was significantly reduced for bone grafts containing undifferentiated cells compared to control (p = 0.035) or scaffolds only (p = 0.05).ConclusionTissue engineered bone grafts induce a pronounced bone formation in artificial bone defects compared to unfilled controls or scaffolds only.