Percentage Of New Bone Research Articles

Effectiveness of the Association of Fibrin Scaffolds, Nanohydroxyapatite, and Photobiomodulation with Simultaneous Low-Level Red and Infrared Lasers in Bone Repair.

Biomaterials and biopharmaceuticals for correcting large bone defects are a potential area of translational science. A new bioproduct, purified from snake venom and fibrinogen from buffalo blood, aroused interest in the repair of venous ulcers. Expanding potential uses, it has also been used to form biocomplexes in combination with bone grafts, associated with physical therapies or used alone. The aim of this preclinical study was to evaluate low-level laser photobiomodulation (PBM) in critical defects in the calvaria of rats filled with nanohydroxyapatite (NH) associated with the heterologous fibrin biopolymer (HFB). Sixty animals were used, divided into six groups (n = 10 each): G1 (NH); G2 (HFB); G3 (NH + HFB); G4 (NH + PBM); G5 (HFB + PBM); G6 (NH + HFB + PBM). PBM simultaneously used red (R) and infrared (IR) light emission, applied intraoperatively and twice a week, until the end of the experiment at 42 days. Microtomography, bone formation can be seen initially at the margins of the defect, more evident in G5. Microscopically, bone formation demonstrated immature and disorganized trabeculation at 14 days, with remnants of grafting materials. At 42 days, the percentage of new bone formed was higher in all groups, especially in G5 (HFB, 45.4 ± 3.82), with collagen fibers at a higher degree of maturation and yellowish-green color in the birefringence analysis with Picrosirius-red. Therefore, it is concluded that the HFB + PBM combination showed greater effectiveness in the repair process and presents potential for future clinical studies.

Critical-sized marginal defects around implants in the rabbit mandible.

The mandible of the rabbit is considered a reliable model to be used to study bone regeneration in defects. The aim of the present study was to evaluate the formation of new bone around implants installed in defects of either 5 or 10mm in the mandible of rabbits. In 12 rabbits, 3mm deep circumferential defect, either 5 or 10mm in diameter, were prepared bilaterally and an implant was placed in the center. A collagen membrane was placed to close the entrance. After 10 weeks, biopsies were taken, histological slides were prepared, and different regions of the defects were analyzed. Similar amounts of new bone were found in both defects. However, most of the 5mm defects were filled with new bone. New bone was observed closing the entrance of the defect and laid onto the implant surface. Only in a few cases the healing was incomplete. Despite a similar percentage of new bone found within the 10mm defects, the healing was incomplete in most of the cases, presenting a low rate of bone formation onto the implant surface within the defect. Only one case presented the closure of the entrance. The dimensions of the defect strongly influenced the healing so that a circumferential marginal defect of 10mm around an implant in the mandible body should be considered a critical-sized defect. The presence of the implant and of residues of teeth might have strongly influenced the healing.

The effect of a barrier membrane on the incorporation of deproteinized bovine bone mineral (DBBM) in experimental defects at the time of early implant placement. A preclinical study

ObjectivesThis study aimed to assess membrane use with a bone substitute graft for guided bone regeneration (GBR) in experimental dehiscence defects.Materials and methodsMaxillary second incisors (I2) in 9 dogs were extracted. Six weeks later, implants were inserted and experimental dehiscence defects (5 × 3 mm) created on the buccal aspect. The defects and surrounding bone were grafted with deproteinized bovine bone mineral. One side (test) was covered with a resorbable collagen membrane whereas the contralateral side (control) was not. After 6 weeks, histomorphometrical analysis was performed to evaluate: (a) first bone-to-implant contact (fBIC), (b) buccal bone thickness at 1 mm increments from implant shoulder, (c) regenerated area (RA), (d) area and percentages of new bone (B), bone substitute (BS) and mineralized tissue (MT).ResultsThe histological appearance was similar between test and control sites. At central and lateral sections, there were no differences between groups for fBIC, buccal bone thickness, RA, BS, B, %B, MT and %MT. At central sections, membrane use favoured more %BS and %MT (p = 0.052). There was significantly more B, %B and MT at lateral compared to central sections.ConclusionsMembrane use tended to retain more bone substitute, but had no effect on new bone ingrowth. Lateral sections showed significantly more bone ingrowth and mineralized tissue compared to central sections, confirming that new bone ingrowth takes place mainly from the lateral walls of the defect.Clinical relevancePreclinical research to clarify the dynamics of bone regeneration in GBR procedures is relevant in clinical practice.

Static and dynamic guided bone regeneration using a shape-memory polyethylene terephthalate membrane: An experimental study in rabbit mandible.

Periosteal expansion (PEO) results in the formation of new bone in the space created between existing bone by expanding the periosteum. PEO has already been performed on rabbit parietal bone and effective new bone formation has been demonstrated. In this study, the utility of a polyethylene terephthalate (PET) membrane as an activator was evaluated in the more complex morphology of the mandible. A PET membrane coated with hydroxyapatite (HA)/gelatine was placed in the rabbit mandibular bone at lower margin of mandibular molar region underneath periosteum, and screw-fixed. In the experimental group, the membrane was bent and screw-fixed along the lateral surface of the bone, with removal of the outer screw after 7 days followed by activation of the membrane. The experimental group was divided into two subgroups: with and without a waiting period for activation. Three animals were euthanized at 3 weeks and another three at 5 weeks postoperatively. Bone formation was assessed using micro-CT as well as histomorphometric and histological methods. No PET membrane-related complications were observed. The area of newly formed bone and the percentage of new bone in the space created by the stretched periosteum did not significantly differ between the control and experimental groups. However, in the experimental group a greater volume was present after 5 weeks than after 3 weeks. Histologically, bone formation occurred close to the site of cortical bone perforation, with many sinusoidal vessels extending through the perforations in the new bone into the overlying fibrous tissue. Inflammatory cells were not seen in the bone.

Effect of platelet rich plasma injection on bone formation in the expanded mid-palatal suture in rabbits: a randomized controlled animal study

BackgroundMid-Palatal suture expansion needs long retention period due to delayed bone formation in the expanded suture. Platelet-rich plasma (PRP) is a concentrated source of growth factors which increase bone formation. The aim of this study was to evaluate the effect of PRP injection on bone formation in expanded mid palatal suture in rabbits.MethodsIn this prospective randomized controlled animal study, Twenty male rabbits (8-weeks-old) were subjected to mid-palatal expansion for 5 days. Animals were afterwards randomly divided into control group A & study group B. PRP was prepared and injected in the mid-palatal suture in animals belonging to group B only. After 6 weeks of retention, all animals were euthanized, and premaxillae were prepared for histological, histomorphometric and immunohistochemical analysis. Student t-test and paired t-test were used to compare the means of the two groups and within the same group respectively. Significance level set at p ≤ 0.05.ResultsHistomorphometric analysis revealed a significant increase (p < 0.001) in the mean percentage of new bone in the study group (14.4%) compared to the control (1.4%). Suture width in study group was significantly wider than the control group (278.8 ± 9μms and 120.4 ± 3.4μms, p < 0.001). There was a significant increase in vascular density in study group than control group (309 ± 65.34 and 243.86 ± 48.1, p = 0.021). Osteopontin immuno-expression revealed a significant increase in optical density in study group than control group (0.21 ± 0.02 & 0.12 ± 0.01, p < 0.001).ConclusionsIn rabbit model, PRP injection can accelerate new bone formation in the expanded mid-palatal suture when compared to the control. This could hopefully result in a more stable midpalatal expansion and a reduced retention period.

Protein arginine methyltransferase 5 in osteoblasts promotes the healing of extraction sockets.

To explore the effect of protein arginine methyltransferase 5 (PRMT5) on tooth extraction sockets healing, we established an extraction sockets model in osteoblast-conditional Prmt5 knockout mice. The results provided clues for promoting extraction sockets healing in clinical settings. Maxillary first molars were extracted from 6 to 8-week-old mice to establish an extraction fossa model. Microcomputed tomography (Micro-CT), histology, and immunostaining assays were performed on samples harvested at 3-, 7-, and 14-day post-extraction. Prmt5-silenced cell lines were employed to explore the regulatory mechanisms underlying the osteigenic differentiation. PRMT5 expression was higher in the early stage of socket healing. Micro-CT analysis showed that the percentage of new bone in the extraction sockets was lower in OC-Cre; Prmt5fl/fl mice than in the control group, consistent with Masson staining. We found that, Prmt5 deficiency delayed the osteogenesis during extraction socket healing, which might be achieved through the decrease of H4R3me2s in the Sp7 promoter region. PRMT5 in osteoblasts may promote the differentiation of osteoblasts by regulating the Sp7 promoter H4R3me2s and participate in the healing of tooth extraction sockets.

Does defect configuration affect the outcomes of alveolar ridge preservation? An experimental in vivo study.

The purpose of this study was to compare the bone healing potential of 1-, 2-, and 3-wall defects following alveolar ridge preservation (ARP) treatment, as well as to evaluate the efficacy of ARP as a treatment option for destructive sites. Three groups, characterized by 1-, 2-, and 3-wall defects, were randomly assigned to the maxillary second, third, and fourth premolars in each of 8 beagle dogs. Each defect was created at either the mesial or distal root site of the tooth, which was hemi-sectioned and extracted. The contralateral root was preserved to superimpose with the experimental site for histomorphometric analysis. For each site, either spontaneous healing (SH; control) or ARP (test intervention) was randomly applied. Each group was divided in half and underwent a healing period of either 4 or 12 weeks. The Mann-Whitney U test and Kruskal-Wallis test were used for histomorphometric analyses. Statistical significance was set at P<0.05. Qualitative analysis revealed a higher percentage of new bone in the apical area compared to the coronal area, regardless of defect type and healing period. In quantitative analysis, the 3-wall defect exhibited a significantly higher percentage of mineralization in the ARP group after 12 weeks of healing (ARP: 61.73%±7.52%; SH: 48.84%±3.06%; P=0.029). An increased percentage of mineralization was observed with a greater number of remaining bony walls, although this finding did not reach statistical significance. Within the limitations of this study, ARP treatment for compromised sockets appears to yield a higher percentage of mineralization compared to SH. Although the effectiveness of the remaining bony walls was limited, their presence appeared to improve the percentage of mineralization in ARP treatment.

Implants Placed with a Ring Technique Using Inlay and Onlay Block Xenografts in the Mandible of Rabbits

Background: Xenogenous bone has been proposed as an alternative to overcome the disadvantages of autogenous grafting. The aim of the present study was to study bone dynamics at inlay and onlay xenografts used for bone augmentation applying a ring technique. Methods: The bone at the lateral surface of the mandibular angle of 12 adult male New Zealand White rabbits was exposed bilaterally. The cortical layer received multiple perforations on one side of the mandible, and a xenograft block of collagenated cancellous equine bone, 7 mm in diameter and 3 mm in width, was fixed on the prepared surface using an implant (onlay group). On the opposite side, a defect 7 mm in diameter and 3 mm in depth was prepared, and the xenograft block was adapted to the defect and fixed with an implant (inlay group). Results: After ten weeks of healing, in the onlay grafts, new bone was mainly formed on the trabeculae surface, reaching in some specimens the most coronal regions of the block. In the inlay grafts, new bone was found arranged on the trabecular surfaces but also occupying the spaces among the trabeculae. The entrance of the defect was often found close to the top of the block by newly formed bone. A higher percentage of new bone was found in the inlay (19.0 ± 9.3%) compared to the onlay (10.4 ± 7.4%) groups (p = 0.031). The mean gain in osseointegration at the implant in relation to the base of the original 3 mm deep defect was 0.95 ± 1.05% in the onlay group and 0.78 ± 0.71% in the inlay group (p = 0.603). Conclusion: The inlay grafts exhibited a higher new bone percentage than the onlay block grafts possibly due to the defect conformation that presented more sources for bone growth. The trabecular conformation and the composition of the grafts made possible the expression of the osteoconductive properties of the material used. This resulted, in several specimens, in the growth of bone on the graft trabeculae toward the most superior regions in both groups and in the closure of the coronal entrance of the defects in the inlay group. The clinical relevance of this experiment is that the ring technique applied as an inlay method could be suitable for bone augmentation.

Preclinical evaluation of a new synthetic carbonate apatite bone substitute on periodontal regeneration in intrabony defects.

To evaluate the potential of a novel synthetic carbonate apatite bone substitute (CO3 Ap-BS) on periodontal regeneration. The use of various synthetic bone substitutes as a monotherapy for periodontal regeneration mainly results in a reparative healing pattern. Since xenografts or allografts are not always accepted by patients for various reasons, a synthetic alternative would be desirable. Acute-type 3-wall intrabony defects were surgically created in 4 female beagle dogs. Defects were randomly allocated and filled with CO3 Ap-BS (test) and deproteinized bovine bone mineral (DBBM) or left empty (control). After 8 weeks, the retrieved specimens were scanned by micro-CT, and the percentages of new bone, bone substitute, and soft tissues were evaluated. Thereafter, the tissues were histologically and histometrically analyzed. Healing was uneventful in all animals, and defects were present without any signs of adverse events. Formation of periodontal ligament and cementum occurred to varying extent in all groups without statistically significant differences between the groups. Residues of both bone substitutes were still present and showed integration into new bone. Histometry and micro-CT revealed that the total mineralized area or volume was higher with the use of CO3 Ap-BS compared to control (66.06 ± 9.34%, 36.11 ± 6.40%; p = .014, or 69.74 ± 2.95%, 42.68 ± 8.68%; p = .014). The percentage of bone substitute surface covered by new bone was higher for CO3 Ap-BS (47.22 ± 3.96%) than for DBBM (16.69 ± 5.66, p = .114). CO3 Ap-BS and DBBM demonstrated similar effects on periodontal regeneration. However, away from the root surface, more new bone, total mineralized area/volume, and higher osteoconductivity were observed for the CO3 Ap-BS group compared to the DBBM group. These findings point to the potential of CO3 Ap-BS for periodontal and bone regeneration.

Histological Comparison of Collagenated Cancellous Equine Bone Blocks Used as Inlay or Onlay for Lateral Bone Augmentation in Rabbits.

The conformation of the recipient site for an inlay graft presents an increased contact with the parent bone compared to an onlay graft. This might favor bone growth within the inlay compared to onlay grafts. Hence, the objective of this study was to compare the bone incorporation and remodeling processes of xenogeneic en bloc grafts placed using two bone grafting techniques, i.e., onlay vs. inlay. In this prospective, randomized, split-mouth study (test and control sides in the same animal), two bone grafting techniques were comparatively evaluated. The lateral aspect of the rabbit mandible was used as the recipient site, bilaterally. On one side of the mandible, the cortical bone was perforated with drills to allow a better bone formation from the bone wound and the marrow spaces. A xenogeneic bone block was fixed in the center of the prepared region, representing the onlay site. On the other side of the mandible, a 7 mm wide and 3 mm deep circumferential defect was prepared using trephines and drills. A xenogeneic bone block was fixed in the center of the defect, representing the inlay site. Two healing periods were applied in the study: 2 and 10 weeks, each represented by 10 rabbits (n = 10 for each period). After 2 weeks of healing, the mean percentage of new bone was 10.4% and 23.3% at the onlay and inlay grafts, respectively (p = 0.022). After 10 weeks of healing, new bone increased to 13.2% at the onlay sites and 25.4% at the inlay sites (p = 0.080). In the 10-week period, the inlay grafts presented a homogeneous growth of new bone in all regions, while in the onlay grafts, low percentages of new bone were observed in the external regions. The percentage of new bone increased faster and was higher in the inlay grafts than in the onlay grafts. This outcome might be related to the self-contained conformation of the recipient site in the inlay group, which offered more sources for new bone formation compared to the one-wall conformation of the recipient sites in the onlay group. The osteoconductive properties of the biomaterial allowed the newly formed bone to reach the most peripheral regions in both groups. The osteoconductive properties of the biomaterial, together with the protection offered by the collagen membrane, allowed marginal closure of the defects by newly formed bone in the inlay group.

Alveolar Ridge Preservation with The Use of Demineralized Bone Matrix Putty: Clinical, Radiographic and Histological Observations in A Case Series

&lt;p&gt;Alveolar ridge preservation (ARP) can minimize alveolar ridge resorption following tooth ex&amp;not;traction and facilitate restorative-driven implant placement. Demineralized bone matrix (DBM) comprises a human allograft that is osteoinductive and osteoconductive. This report describes radiographic, histologic and clinical findings of ARP using DBM putty and non-resorbable high-density polytetrafluoroethylene (d-PTFE) membrane in three cases. &lt;/p&gt; &lt;p&gt;Materials and Methods: From January 2018 to May 2018, three patients underwent the ARP procedure. The surgery involved atraumatic extraction, socket debridement, filling the socket with DBM putty, applying a d-PTFE membrane, and suturing with 5-0 nylon. After healing for 6&amp;ndash;7 months, an implant was placed and biopsy specimens were collected simultaneously. Using the same customized surgical stent and computed tomography, the preoperative and postoperative alveolar ridge heights and widths were measured. Histological evaluations in&amp;not;cluding the percentage of newly formed bone, residual graft particles, and fibrous connective tissue were performed. &lt;/p&gt; &lt;p&gt;Results: In all three cases, the health status of the hard and soft tissue improved (mean fol&amp;not;low-up: 54 months). Guided bone regeneration was not required during implant placement. Radiographically, the mean change was 0.5 mm in the alveolar ridge height and 1.2, 0.87, and 0.73 mm in the alveolar ridge width at 2, 4, and 6 mm apical to the initial vertical measure&amp;not;ment, respectively. Histologically, the mean percentage of new bone, residual graft particles, and fibrous connective tissue was 40.5&amp;plusmn;5.9%, 10.7&amp;plusmn;6.9%, and 48.8&amp;plusmn;9.6%, respectively, and the voids were not included in these calculations. &lt;/p&gt; &lt;p&gt;Conclusion: This case series demonstrated the effectiveness of DBM putty as a biocompatible filler in extraction sockets for ridge preservation prior to implantation. Further longitudinal studies regarding the efficacy and stability of DBM putty in ridge preservation are required.&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Pretreatment of Mesenchymal Stem Cells with Electrical Stimulation as a Strategy to Improve Bone Tissue Engineering Outcomes.

Electrical stimulation (EStim), whether used alone or in combination with bone tissue engineering (BTE) approaches, has been shown to promote bone healing. In our previous in vitro studies, mesenchymal stem cells (MSCs) were exposed to EStim and a sustained, long-lasting increase in osteogenic activity was observed. Based on these findings, we hypothesized that pretreating MSC with EStim, in 2D or 3D cultures, before using them to treat large bone defects would improve BTE treatments. Critical size femur defects were created in 120 Sprague-Dawley rats and treated with scaffold granules seeded with MSCs that were pre-exposed or not (control group) to EStim 1 h/day for 7 days in 2D (MSCs alone) or 3D culture (MSCs + scaffolds). Bone healing was assessed at 1, 4, and 8 weeks post-surgery. In all groups, the percentage of new bone increased, while fibrous tissue and CD68+ cell count decreased over time. However, these and other healing features, like mineral density, bending stiffness, the amount of new bone and cartilage, and the gene expression of osteogenic markers, did not significantly differ between groups. Based on these findings, it appears that the bone healing environment could counteract the long-term, pro-osteogenic effects of EStim seen in our in vitro studies. Thus, EStim seems to be more effective when administered directly and continuously at the defect site during bone healing, as indicated by our previous studies.

Efficiency analysis of commercial polymeric membranes for bone regeneration in rat cranial defects.

To evaluate the in vivo efficiency of commercial polymeric membranes for guided bone regeneration. Rat calvarial critical size defects was treated with LuminaCoat (LC), Surgitime PTFE (SP), GenDerm (GD), Pratix (PR), Techgraft (TG) or control (C-) and histomorphometric analysis determined the percentage of new bone, connective tissue and biomaterial at 1 or 3 months. Statistical analysis used ANOVA with Tukey's post-test for means at same experimental time and the paired Student's t test between the two periods, considering p < 0.05. New bone at 1 month was higher for SP, TG and C-, at 3 months there were no differences, and between 1 and 3 months PR had greater increase growthing. Connective tissue at 1 month was higher for C-, at 3 months for PR, TG and C-, and between 1 and 3 months C- had sharp decline. Biomaterial at 1 month was higher for LC, in 3 months for SP and TG, and between 1 and 3 months, LC, GD and TG had more decreasing mean. SP had greater osteopromotive capacity and limitation of connective ingrowth, but did not exhibit degradation. PR and TG had favorable osteopromotion, LC less connective tissue and GD more accelerated biodegradation.

The impact of polydeoxyribonucleotide on early bone formation in lateral-window sinus floor elevation with simultaneous implant placement.

The aim of this study was to evaluate the impact of polydeoxyribonucleotide (PDRN) on histologic outcomes when implant placement and lateral sinus floor elevation are performed simultaneously. Three bimaxillary premolars (P2, P3, and P4) were extracted from 4 beagle dogs 2 months before lateral sinus floor elevation. After lateral elevation of the sinus membrane, each sinus was allocated to either the test or control group. Sinuses underwent either 1) collagenated synthetic bone graft with PDRN following lateral sinus floor elevation (test group) or 2) collagenated synthetic bone graft without PDRN after lateral sinus floor elevation (control group). Eight weeks after the surgical procedure, all animals were euthanised for a histologic and histomorphometric assessment. Augmented height (AH), protruding height (PH), and bone-to-implant contact in pristine (BICp) and augmented (BICa) bone were measured. The composition of the augmented area, which was divided into 3 areas of interest located in coronal, middle and apical areas (AOI_C, AOI_M, and AOI_A), was calculated with 3 parameters: the area percentage of new bone (pNB), residual bone graft particle (pRBP), and fibrovascular connective tissue (pFVT). AH, PH, BICp, BICa total, BICa coronal, and BICa middle values were not significantly different between sinuses in the control and test groups (all P>0.05). The BICa apical of sinuses in the test group (76.7%±9.3%) showed statistically higher values than those of sinuses in the control group (55.6%±22.1%) (P=0.038). pNB, pRBP, and pFVT showed statistically significant differences between the 2 groups in AOI_A (P=0.038, P=0.028, and P=0.007, respectively). pNB, pRBP, and pFVT in AOI_C and AOI_M were not significantly different between samples in the control and test groups (all P>0.05). The histologic findings revealed that lateral sinus floor elevation with PDRN might improve early new bone formation and enable higher bone-to-implant contact.

Healing Patterns of Non-Collagenated Bovine and Collagenated Porcine Xenografts Used for Sinus Floor Elevation: A Histological Study in Rabbits.

Objective: To compare healing of collagenated and non-collagenated xenografts used for maxillary sinus floor elevation. Materials and Methods: Two different xenografts were used: deproteinized bovine bone (DBBM group) and collagenated corticocancellous porcine bone (collagenated group). Healing was studied after 2, 4, and 8 weeks. The loss of dimensions of the elevated area and the percentages of new bone, xenograft remnants, osteoclastic zones, vessels, inflammatory infiltrates, and soft tissues were analyzed. Three regions were evaluated: close to the bone walls (bone wall region), subjacent the sinus mucosa (submucosa region), and the center of the elevated area (middle region). The primary variables were the percentage of new bone and xenograft remnants. Results: Between 2 and 8 weeks, the elevated areas showed a reduction of 16.3% and 52.2% in the DBBM and collagenated groups, respectively (p < 0.01 between the two areas after 8 weeks). After 8 weeks, the highest content of new bone was observed in the bone wall region, which was higher in the collagenated group than in the DBBM group (41.6% and 28.6%, respectively; p < 0.01). A similar quantity of new bone was found between the two groups in other regions. A higher percentage of vessels in all regions evaluated (p < 0.01) and soft tissue in the sub-mucosa region (p < 0.05) was found in the collagenated group than in the DBBM group. Conclusions: The present study showed that both xenografts allowed new bone formation. In comparison with the non-collagenated xenograft, the collagenated xenograft underwent higher resorption, resulting in greater shrinkage of the elevated space after sinus lifting and a higher content of new bone in the regions close to the bone walls. Clinical relevance: In this study, the region adjacent to the bone wall showed the highest new bone content. This region resembles the base of the sinus, closest to the sinus floor and walls, and is the most important region from a clinical point of view because it is where the implant will be installed. Residues of the biomaterial remained after 8 weeks of healing. Other reports have shown that these biomaterial residues may interfere with the integration of implants.

Contribution to Bone Formation of the Schneiderian Membrane after Sinus Augmentation: A Histological Study in Rabbits.

to evaluate bone formation in close contact with the sinus mucosa after different periods from sinus augmentation and the influence on healing of the presence of an inward dis-placed bone window. Eighteen rabbits were included in the experiment. A trap-door technique was applied at the test sites, and the bony window was elevated inward (inward window; IW) together with the sinus mucosa. At the control sites, the bony window was removed before the elevation of the sinus mucosa. The elevated space was filled with deproteinized bovine bone mineral (DBBM) and both access windows were covered with a collagen membrane. Histometric measurements were performed subjacent the sinus mucosa after 2, 4, and 8 weeks of healing. Very few sinuses presented small percentages of new bone in close contact with the sinus mucosa in the various period examined. The presence of bone in the neighbor areas might have influenced bone formation close to the sinus mucosa. The inward displaced bone window supported bone formation close to the sinus mucosa only in the earliest period of healing, while the bone walls increased their influence over time. The lack of increased new bone percentage over time in the most central regions of the elevated sinus mucosa do not support the hypothesis that the sinus mucosa may express its potential in bone formation. It can be speculated that the new bone found in the intermediate and middle regions of the control sites in the earliest period of healing might be due to residual of bone from the osteotomy. Very small amounts of new bone were found subjacent to the sinus mucosa, mostly formed from the bone walls, the inward displaced bone window or from possible bone residues from the osteotomy procedures. The lack of increased new bone percentage over time in the most central regions of the elevated sinus mucosa indicates that the contribution to bone formation provided by the sinus mucosa is limited.

Acceleration of Bone Fracture Healing through the Use of Bovine Hydroxyapatite or Calcium Lactate Oral and Implant Bovine Hydroxyapatite-Gelatin on Bone Defect Animal Model.

Bone grafts a commonly used therapeutic technique for the reconstruction and facilitation of bone regeneration due to fractures. BHA-GEL (bovine hydroxyapatite-gelatin) pellet implants have been shown to be able accelerate the process of bone repair by looking at the percentage of new bone, and the contact between the composite and bone. Based on these results, a study was conducted by placing BHA-GEL (9:1) pellet implants in rabbit femoral bone defects, accompanied by 500 mg oral supplement of BHA or calcium lactate to determine the effectiveness of addition supplements. The research model used was a burr hole defect model with a diameter of 4.2 mm in the cortical part of the rabbit femur. On the 7th, 14th and 28th days after treatment, a total of 48 New Zealand rabbits were divided into four groups, namely defect (control), implant, implant + oral BHA, and implant + oral calcium lactate. Animal tests were terminated and evaluated based on X-ray radiology results, Hematoxylin-Eosin staining, vascular endothelial growth Factor (VEGF), osteocalcin, and enzyme-linked immunosorbent assay (ELISA) for bone alkaline phosphatase (BALP) and calcium levels. From this research can be concluded that Oral BHA supplementation with BHA-GEL pellet implants showed faster healing of bone defects compared to oral calcium lactate with BHA-GEL pellet implants.

Effects of hydroxyapatite associated to collagen type I graft in bone repair of critical defects in rabbits

The aim of this investigation was to evaluate the influences of a malleable bone graft composed by hydroxyapatite and collagen type I in bone formation. Three surgical sites of critical size were prepared in twelve rabbits’ calvarias. The control defect was fulfilled with blood clot and the experimental defects were fulfilled with the graft. The euthanasia occurred in three times: 4, 8 and 12 weeks after the surgical procedures. The specimens were analyzed in light, fluorescence and scanning electronic microscopes. The quantitative evaluation was made by histomorphometric analysis, in order to calculate the percentage of new bone formed and the area of the hydroxyapatite particles. The results were submitted to two way ANOVA test and Tukey`s post hoc. New bone formation was accelerated in early stages of the healing process. It was seen more intensive bone formation in the periosteum side than in the dura mater membrane side in all groups. Besides that, in experimental sides the new bone was surrounding the hydroxyapatite particles with minimal amount of inflammatory cells, which confirmed the biocompatibility and osteoconduction properties of this material. Besides that, the hydroxyapatite particles showed gradual and progressive absorption at the same time that the bone was being formed.

Bone Response to Osteopontin-Functionalized Carboxyethylphosphonic Acid-Modified Implants. Experimental Study in a Minipig Model

Currently, dental implants have become a common and reliable treatment for restoring masticatory function in edentulous patients. Their surface topography is of great importance for the adhesion and remodeling of bone cells, both in the initial phases and over time, and different strategies have been proposed to improve the biological performance of conventional sandblasted, large-grit, acid-etched implant surfaces. Corrosion has been identified as one of the causes of implant failure due to contact with oral fluids. Carboxyethylphosphonic acid is a potent anticorrosive that would form stable bonds with titanium oxide, generating an organic layer on which modifications could be made to improve cell adhesion. Osteopontin is considered a molecule capable of improving the osseointegration of titanium. Our study evaluated the osseointegration capacity of titanium implants modified with carboxyethylphosphonic acid and functionalized with osteopontin in a minipig model. A total of 16 implants were inserted in the tibial diaphysis of two minipigs, 8 implants modified with carboxyethylphosphonic acid and functionalized with osteopontin from the experimental group and 8 from the control group with sandblasted, large-grit, acid-etched surface treatment. After 4 weeks, the animals were sacrificed and the samples were analyzed by histomorphometric analysis, assessing bone-implant contact, cortical bone-implant contact, percentage of new bone, peri-implant bone density and interthread bone area interthread. Statistical analysis was performed using SPSS v.18. Statistical significance was found between groups for the percentage of new bone (p = 0.04) and for interthread bone area interthread (p = 0.01). Functionalization of titanium surfaces by osteopontin may be of interest for conditioning bone remodeling in the early stages of osseointegration, although more in vivo studies are needed to determine its real influence in this aspect.

Biological Behavior of Xenogenic Scaffolds in Alcohol-Induced Rats: Histomorphometric and Picrosirius Red Staining Analysis.

In this experimental protocol, the objective was to evaluate the biological behavior of two xenogenic scaffolds in alcohol-induced rats through histomorphometric and Picrosirius Red staining analysis of non-critical defects in the tibia of rats submitted or not to alcohol ingestion at 25% v/v. Eighty male rats were randomly divided into four groups (n = 20 each): CG/B (water diet + Bio-Oss® graft, Geistlich Pharma AG, Wolhusen, Switzerland), CG/O (water diet + OrthoGen® graft, Baumer, Mogi Mirim, Brazil), AG/B (25% v/v alcohol diet + Bio-Oss® graft), and AG/O (25% v/v alcohol diet + OrthoGen® graft). After 90 days of liquid diet, the rats were surgically obtained, with a defect in the tibia proximal epiphysis; filled in according to their respective groups; and euthanized at 10, 20, 40 and 60 days. In two initial periods (10 and 20 days), all groups presented biomaterial particles surrounded by disorganized collagen fibrils. Alcoholic animals (AG/B and AG/O) presented, in the cortical and medullary regions, a reactive tissue with inflammatory infiltrate. In 60 days, in the superficial area of the surgical cavities, particles of biomaterials were observed in all groups, with new compact bone tissue around them, without complete closure of the lesion, except in non-alcoholic animals treated with Bio-Oss® xenograft (CG/B), where the new cortical interconnected the edges of the defect. Birefringence transition was observed in the histochemical analysis of collagen fibers by Picrosirius Red, in which all groups in periods of 10 and 20 days showed red-orange birefringence, and from 40 days onwards greenish-yellow birefringence, which demonstrates the characteristic transition from the formation of thin and disorganized collagen fibers initially to more organized and thicker later. In histomorphometric analysis, at 60 days, CG/B had the highest volume density of new bone (32.9 ± 1.15) and AG/O the lowest volume density of new bone (15.32 ± 1.71). It can be concluded that the bone neoformation occurred in the defects that received the two biomaterials, in all periods, but the Bio-Oss® was superior in the results, with its groups CG/B and AG/B displaying greater bone formation (32.9 ± 1.15 and 22.74 ± 1.15, respectively) compared to the OrthoGen® CG/O and AG/O groups (20.66 ± 2.12 and 15.32 ± 1.71, respectively), and that the alcoholic diet interfered negatively in the repair process and in the percentage of new bone formed.