Bone formation with two types of grafting materials: a histologic and histomorphometric study

Biological Effects of Orthodontic Tooth Movement on the Periodontium in Regenerated Bone Defects: A Scoping Review

The aim of this scoping review is to analyse the biological effects of the orthodontic tooth movement (OTM) in areas with bone defects that are undergoing regeneration using different types of regenerative materials and techniques. The electronic research was performed on four databases as follows: PubMed, Scopus, EMBASE, and Web of Science. Data were extracted according to publication information, study design, sample characteristics, parameters of OTM, biological repercussions on the periodontium complex, methods of analysis, and conclusions. A total of thirty studies were included in the final review. In twenty-two studies, the most widely adopted grafting materials were alloplastics. In most studies, the orthodontic force used was 10 or 100 g, and the timing of application ranged from immediate to 6 months after grafting surgery. Twenty-four studies showed an increase in osteogenesis; in five studies, the clinical attachment level (CAL) increased; in five others, the probing pocket depth (PPD) decreased; in sixteen studies, there was root resorption of a different magnitude. Though the effects of OTM on the periodontium in the grafted areas were positive, the outcomes should be interpreted with caution as future preclinical and clinical studies are needed to extrapolate more valid conclusions.

Experimental model of normotrophic pseudarthrosis of a rabbit’s tibia

Background. The formation of a pseudarthrosis is one of the most severe complications of bone fractures. Pseudarthrosis occurs as a result of a disorder in the fracture union, has a poor prognosis and requires long-term treatment and repeated surgeries. A small number of representative pseudarthrosis models makes it difficult to conduct preclinical studies of promising pharmacological substances, bone replacement materials and surgical methods of treatment.The aim. To develop and to validate an experimental model of normotrophic pseudarthrosis of a rabbit’s tibia by creating diastasis between bone fragments, forming local vascularization disturbance and using unstable fixation.Materials and methods. The study was carried out on Soviet Chinchilla rabbits. The animals were divided into 2 groups: in experimental group, we formed tibial pseudarthrosis; in control group, we made a simple transverse tibial fracture. The pseudarthrosis was formed by segmental resection (5 mm) of the middle third of the tibia, bone fragments dilatation for 5 mm, removal of periosteum and bone marrow within 5 mm followed by daily destabilization of a fracture in an external fixation device. The duration of the experiment was 6 weeks. X-ray examination of the fracture area was carried out weekly, multi-layer spiral computed tomography (MSCT) and histological examinations were carried out at the end of the experiment.Results. The survival value in the experiment was 100 %. According to weekly X-ray examination, fracture union was registered only in the control group and occurred on average on the 22,8 ± 5,1 day, while the formation of pseudarthrosis was observed only in the experimental group, and radiographic signs of a pseudarthrosis were noted on average on the 33,6 ± 3,5 day. The formation of a pseudarthrosis by the end of the experiment was confirmed by MSCT and histological studies.Conclusions. The developed model of the normotrophic pseudarthrosis of a rabbit’s tibia can be used for experimental tests of various factors for stimulating reparative regeneration and methods for treatment of the pseudarthrosis.

Evaluation of New Octacalcium Phosphate-Coated Xenograft in Rats Calvarial Defect Model on Bone Regeneration

Bone graft material is essential for satisfactory and sufficient bone growth which leads to a successful implant procedure. It is classified into autogenous bone, allobone, xenobone and alloplastic materials. Among them, it has been reported that heterogeneous bone graft material has a porous microstructure that increases blood vessels and bone formation, and shows faster bone formation than other types of bone graft materials. We observed new bone tissue formation and bone remodeling using Ti-oss^® (Chiyewon Co., Ltd., Guri, Korea), a heterologous bone graft material. Using a Sprague–Dawley rat calvarial defect model to evaluate the bone healing effect of biomaterials, the efficacy of the newly developed xenograft Ti-oss^® and Bio-Oss^® (Geistilch Pharma AG, Wolhusen, Switzerland). The experimental animals were sacrificed at 8 and 12 weeks after surgery for each group and the experimental site was extracted. The average new bone area for the Ti-oss^® experimental group at 8 weeks was 17.6%. The remaining graft material was 22.7% for the experimental group. The average new bone area for the Ti-oss^® group was 24.3% at 12 weeks. The remaining graft material was 22.8% for the experimental group. It can be evaluated that the new bone-forming ability of Ti-oss^® with octacalcium phosphate (OCP) has the bone-forming ability corresponding to the conventional products.

Osteogenic Potential of Bovine Bone Graft in Combination with Laser Photobiomodulation: An Ex Vivo Demonstrative Study in Wistar Rats by Cross-Linked Studies Based on Synchrotron Microtomography and Histology

BACKGROUND

Alveolar bone defects are usually the main concern when planning implant treatments for the appropriate oral rehabilitation of patients. To improve local conditions and achieve implant treatments, there are several methods used for increasing bone volume, among which one of the most successful, versatile, and effective is considered to be guided bone regeneration. The aim of this demonstrative study was to propose an innovative analysis protocol for the evaluation of the effect of photobiomodulation on the bone regeneration process, using rat calvarial defects of 5 mm in diameter, filled with xenograft, covered with collagen membrane, and then exposed to laser radiation.

METHODS

The animals were sacrificed at different points in time (i.e., after 14, 21, and 30 days). Samples of identical dimensions were harvested in order to compare the results obtained after different periods of healing. The analysis was performed by cross-linking the information obtained using histology and high-resolution synchrotron-based tomography on the same samples. A comparison was made with both the negative control (NC) group (with a bone defect which was left for spontaneous healing), and the positive control (PC) group (in which the bone defects were filled with xenografts and collagen membrane without receiving laser treatment).

RESULTS

We demonstrated that using photobiomodulation provides a better healing effect than when receiving only the support of the biomaterial. This effect has been evident for short times treatments, i.e., during the first 14 days after surgery.

CONCLUSION

The proposed analysis protocol was effective in detecting the presence of higher quantities of bone volumes under remodeling after photobiomodulation with respect to the exclusive bone regeneration guided by the xenograft.

Comparison between fractal analysis and radiopacity evaluation as a tool for studying repair of an osseous defect in an animal model using biomaterials

OBJECTIVES

To evaluate bone repair of an osseous defect in a rat animal model through fractal analysis and radiopacity analysis in radiographic images.

METHODS

120 rats were subjected to extraction of their first molar and divided into four groups (n = 6/group) according to the material used for bone grafting: mineralized bovine bone, demineralized bovine bone (DBB), blood clot (BC - control) or Bio-Oss^® (BO). The animals were sacrificed after 1, 7, 14, 21 and 49 days and subjected to radiographic evaluation. For fractal analysis (FA), a square regionof interest of 30 × 30 pixels was used, and radiopacity was measured as the mean gray scale (MGS) value for three points of 5 × 5 pixels in the apical, medial and coronal regions of the defect. Histomorphometric evaluation was realized as the gold standard for bone neo-formation and maturation of the new osseous matrix.

RESULTS

Histomorphometric evaluation suggested that DBB showed faster mineralized deposition and resulted in more mature bone at the final time point of evaluation. Mineralized bovine bone and Bio-Oss presented similar results. The mineralized groups did not show significant differences in bone maturation. The radiopacity analysis revealed a significant difference (p < 0.05) between the DBB and blood clot groups at the final time point. FA did not show any significant differences at the final time point.

CONCLUSIONS

Mean gray scale seemed to be more effective for the quantification of bone repair than FA in the demineralized group in this animal model. Results for the mineralized groups did not reveal a significant difference, leading to the conclusion that both methods are effective.

Complications after craniofacial reconstruction with calcium phosphate cements: a case report and review of the literature

Among different graft materials for craniofacial reconstruction, calcium phosphate cements have the advantages of alloplastic grafts and wide use. The authors report a case of foreign body reaction following frontal reconstruction with JectOS (an injectable calcium orthophosphate cement; Kasios) and reviewed the literature on complications of this material after craniofacial reconstruction from 2002 to 2017. Complications were categorized into two groups: immunologic reactions (consisting of seroma collection, chronic sinus mucosa swelling, and foreign body reaction) and non-immune events (infection, fragmentation, and ejection). It is wise to use calcium phosphate-based material only in selected cases with small defects, and long-term follow-up is needed to observe their consequences.

Vitamin K and Bone Metabolism: A Review of the Latest Evidence in Preclinical Studies

Bone is a metabolically active tissue that renews itself throughout one's life. Cytokines along with several hormonal, nutritional, and growth factors are involved in tightly regulated bone remodeling. Accordingly, vitamin K as a multifunctional vitamin has been recently deemed appreciable as a topic of research as it plays a pivotal role in maintenance of the bone strength, and it has been proved to have a positive impact on the bone metabolism. Vitamin K exerts its anabolic effect on the bone turnover in different ways such as promoting osteoblast differentiation, upregulating transcription of specific genes in osteoblasts, and activating the bone-associated vitamin k dependent proteins which play critical roles in extracellular bone matrix mineralization. There is also credible evidence to support the effects of vitamin k2 on differentiation of other mesenchymal stem cells into osteoblast. The main objective of the present paper is to comprehensively outline the preclinical studies on the properties of vitamin K and its effects on the bone metabolism. The evidence could shed light on further clinical studies to improve osteogenesis in bone graft surgeries.

Purification processes of xenogeneic bone substitutes and their impact on tissue reactions and regeneration

Xenogeneic bone substitute materials are widely used in oral implantology. Prior to their clinical use, purification of the former bone tissue has to be conducted to ensure the removal of immunogenic components and pathogens. Different physicochemical methods are applied for purification of the donor tissue, and temperature treatment is one of these methods. Differences in these methods and especially the application of different temperatures for purification may lead to different material characteristics, which may influence the tissue reactions to these materials and the related (bone) healing process. However, little is known about the different material characteristics and their influences on the healing process. Thus, the aim of this mini-review is to summarize the preparation processes and the related material characteristics, safety aspects, tissue reactions, resorbability and preclinical and clinical data of two widely used xenogeneic bone substitutes that mainly differ in the temperature treatment: sintered (cerabone^®) and non-sintered (Bio-Oss^®) bovine-bone materials. Based on the summarized data from the literature, a connection between the material-induced tissue reactions and the consequences for the healing processes are presented with the aim of translation into their clinical application.

Effect of Semelil, an Herbal Selenium-Based Medicine, on New Bone Formation in Calvarium of Rabbits

Background

This study aims to analyze the effect of Semelil, an herbal selenium-based medicine, on osteogenesis in rabbit calvarium defects.

Methods

Four identical bony defects (8 mm) were created in the calvarium of 16 New Zealand male rabbits and filled randomly with xenogenic bone substitute material (Bio-Oss®) and semelil herbal drug (ANGIPARS™). One site was filled with Bio-Oss (B); the second site was treated with ANGIPARS (A); the third site was treated with ANGIPARS + Bio-Oss (AB); and the fourth site was left as untreated control (C) and defects were left unfilled. Rabbits were randomly divided into two groups (n = 8) and sacrificed at four and eight weeks. Percentage of new bone formation, type of the newly formed bone, percentage of the remaining xenograft biomaterial, and foreign body reaction (FBR) were evaluated via histological and histomorphometric analyses.

Results

The percentage of new bone formation was significantly different among four groups. The highest effect was observed in AB, followed by A, B, and C groups, respectively. The difference in the mean percentage of new bone formation between four and eight weeks was significant for all four groups (P < 0.001). Regarding bone formation, the interaction effect of A and B was significant at four (P < 0.001) and eight weeks (P = 0.002). ANGIPARS alone and in presence of Bio-Oss enhanced new bone formation at both four and eight weeks (P < 0.001). The mean amount of new bone formation was significantly different at four and eight weeks in groups C (P = 0.008), A (P < 0.001), B (P < 0.001), and AB (P = 0.003). FBR was not observed in any group.

Conclusion

Semelil may be useful as an adjunct to conventional osteoconductive materials in order to enhance osteogenesis.

Design of novel injectable in-situ forming scaffolds for non-surgical treatment of periapical lesions: In-vitro and in-vivo evaluation

Periapical lesions are considered one of the common pathological conditions affecting alveolar bone. The primary focus of this study was to investigate the effectiveness of formulating an injectable in-situ forming scaffold-loaded with risedronate (bone resorption inhibitor) and with lornoxicam (anti-inflammatory drug) for the non-surgical treatment of periapical lesions. The scaffolds were prepared using solvent-induced phase inversion technique. Two insoluble copolymers were investigated namely; PLGA (ester-terminal) and PLGA-A (acid-terminal), additionally, SAIB was added as a high viscosity water-insoluble carrier. The addition of porogenic agents like hydrolyzed collagen was also investigated. The prepared scaffolds were characterized by analyzing their in-vitro release, DSC and rheological properties, besides their morphological properties. The results showed that the scaffolds prepared using 30% (w/v) PLGA or combined PLGA: SAIB (1:1, w/w) with total polymer concentration of 30% (w/v) possessed the most sustained drug release profile. Selected scaffolds were tested for their therapeutic effect to study the effect of porogenic agent, anti-inflammatory drug and risedronate in periapical lesions induced in dogs' teeth. Results declared that the selected scaffolds succeeded in improving the inflammation and enhancing the formation of new bony regions confirming the success of the prepared scaffolds as an innovative approach in the treatment of bone defects.

Histologic and histomorphometric evaluation of bone regeneration using nanocrystalline hydroxyapatite and human freeze-dried bone graft : An experimental study in rabbit

PURPOSE

Bone regeneration is an important concern in periodontal treatment and implant dentistry. Different biomaterials and surgical techniques have been used for this purpose. The aim of the present study was to compare the effect of nanocrystalline hydroxyapatite and human freeze-dried bone graft (FDBG) in regeneration of rabbit calvarium bony defects by histologic and histomorphometric evaluation.

METHODS

In this experimental study, three similar defects, measuring 8 mm in diameter, were created in the calvaria of 16 white New Zealand rabbits. Two defects were filled with FDBG and nanocrystalline hydroxyapatite silica gel, while the other one remained unfilled to be considered as control. All the defects were covered with collagen membranes. During the healing period, two animals perished; so 14 rabbits were divided into two groups: half of them were euthanized after 6 weeks of healing and the other half after 12 weeks. The specimens were subjected to histologic and histomorphometric examinations for assessment of the following variables: percentage of bone formation and residual graft material, inflammation scores, patterns of bone formation and type of newly formed bone.

RESULTS

The percentages of new bone formation after 6 weeks were 14.22 ± 7.85, 21.57 ± 6.91, and 20.54 ± 10.07% in FDBG, NanoBone, and control defects. These values were 27.54 ± 20.19, 23.86 ± 6.27, and 26.48 ± 14.18% in 12-week specimens, respectively. No significant differences were found in the amount of bone formation between the groups. With regard to inflammation, the control and NanoBone groups showed significantly less inflammation compared to FDBG at the 6-week healing phase (P = 0.04); this difference was not significant in the 12-week specimens.

CONCLUSIONS

Based on the results of this experimental study, both NanoBone and FDBG exhibited a similar effect on bone formation.

Histological and histomorphometric evaluation of the synthetic biomaterial Natix® in horizontal reconstruction of alveolar ridge

BACKGROUND

Following loss of teeth, atrophy of alveolar ridge of the jaws is a substantial problem and unintended outcome that compels clinicians to perform bone reconstruction ahead of implant placement. Although autogenous bone is recommended as the gold standard in bone reconstruction, aninvasive second surgery harvestinga limited volume of bone (from intraoral source) has led a significant approachingthe use of synthetic bone substitute materials. The aim of this study was to evaluate the histologic and histomorphometric properties of porous titanium granules (Natix^®) used in horizontal reconstruction of alveolar ridge before implant placement.

MATERIALS AND METHODS

In the present quasi-experimental clinical trial, four patients (three females and one male) needed horizontal bone augmentation on ten areas of edentulous mandibular ridge before implant treatment. During surgery, the buccal aspect of edentulous ridge was augmented by Natix^®, covered by resorbable membrane (Cytoplast^®). After 8 months, 10 core biopsies were obtained.

RESULTS

In histological study, no foreign body reaction at the site of the newly formed bone or around the biomaterial residue was observed. Newly formed bone was fully vital with large lacunae containing osteocytes. In 60% of cases, connective tissue was observed at the biomaterial - new bone interface. In histomorphometric study, mean percentage of bone formation was 40.56% ± 19.83% and mean bone trabecular thickness was 39.98 ± 17.54 μ.

CONCLUSION

Despite acceptable histological and histomorphometric bone formation findings, in clinical terms, no increase was created in the horizontal dimension. Thus, it seems that application of this biomaterial in horizontal reconstruction of alveolar ridges with noncontained defects is inappropriate.

Assessment of bone healing in rabbit calvaria grafted with three different biomaterials

This study evaluated the bone regeneration process in rabbit calvaria induced by three types of biomaterials: two xenogenous, consisting of deproteinized bovine bone, while the other was alloplastic, based on biphasic calcium phosphate. Five New Zealand white rabbits weighing between 2,900 and 3,500 g were submitted to four standard 8 mm-diameter perforations at the parietal bone. Three perforations were filled with three grafts and biomaterials, two of them received bovine Bio-Oss® and Endobon® Xenograft Granules, and the other consisted of fully alloplastic Straumann® Bone Ceramic. The fourth remaining cavity was used as control with coagulum. After eight weeks, the animals were sacrificed, and the samples were prepared for morphometric and qualitative analysis. The cavities filled with alloplastic biomaterials showed higher percentages of newly formed bone (p<0.05), while the cavities with xenogenous biomaterials showed higher amount of residual graft (p<0.05). Although the results showed greater bone formation with Straumann® Bone Ceramic, further studies are required to prove which is the more effective biomaterial for bone induction process.

Tissue reaction of deproteinized bovine bone matrix grafting in ectopic site: histological study on sheep

The aim of this paper was to evaluate through histological analysis of the tissue reaction of deproteinized bovine bone matrix (DBBM) when inserted into the site of intramuscular ectopic sheep. In this study, 16 sheep received 3 groups and these were divided into 2 experimental times: Group 1-sham group, Group 2-particulate autogenous bone and Group 3-DBBM granules. All animals underwent surgical procedures for insertion of materials in an ectopic site (muscles of the lower back and after 3 and 6 months postoperatively, the samples were evaluated by histological analysis. The results indicated that the Sham group showed dense collagen fibers and thin, characterizing fibrosis at 3 and 6 months. In the autograft group there was a significant amount of collagen deposition and decreased inflammation at 6 months postoperatively. Group of DBBM, it was noted the presence of dense connective tissue and surrounding remaining particles was observed the formation of with osteoid characteristic tissue. The DBBM demonstrated biocompatibility, osteoconductivity and small osteogenesis capacity on ectopic site.

Radiographic and histological evaluation of ectopic application of deproteinized bovine bone matrix

OBJECTIVE

To evaluate, through radiographic and histological analysis, the tissue reaction induced by a biomaterial based on deproteinized bovine bone matrix (DBBM) in the muscle of sheep.

MATERIALS AND METHODS

Sixteen sheep were used. The animals underwent surgery to insert polyethylene tubes containing the biomaterial in the muscle of the lower back (ectopic site) and were euthanized after 3 and 6 months. Each sheep received three tubes: Group 1 - sham group (negative control - tube without biomaterial), Group 2 - particulate autogenous bone (positive control), and Group 3 - DBBM biomaterial (GenOx Inorg). The material removed was evaluated by radiographic, macroscopic, and microscopic analysis, descriptively.

RESULTS

Macroscopic analysis showed that Group 3 had a greater tissue volume maintenance. Microscopic analysis indicated that Group 1 had a higher concentration of dense, thin collagen fibers (3 and 6 months); in Group 2, there was a decrease in the inflammatory process and the deposition of dense, thin collagen fibers (3 and 6 months); in Group 3, the presence of a dense connective tissue was noted, in which the DBBM particles (3 months) were found. On the periphery of these particles, a deposition of basophilic material was found, indicating the formation of mineral particles and the formation of tissues with osteoid characteristics (6 months).

CONCLUSION

Based on the results obtained, it can be concluded that the biomaterial based on DBBM led to the formation of tissue with similar characteristics to an osteoid matrix in a postoperative period of 6 months. However, none of the groups evaluated showed ectopic bone neoformation.

Regenerative Effects of Three Types of Allografts on Rabbit Calvarium: An Animal Study

OBJECTIVES

The aim of this study was to histologically compare the regenerative properties of two allografts manufactured by two Iranian companies.

MATERIALS AND METHODS

In this study, four 8-mm defects were produced in the calvaria of 12 rabbits. In three defects, three types of allografts namely ITB, CenoBone and Grafton were placed and one defect served as control. Samples were prepared and histomorphometric evaluations were carried out after healing periods of four weeks (interval 1) and eight weeks (interval 2). Qualitative and quantities variables were compared and analyzed with SPSS software.

RESULTS

Mild inflammation was observed in 45% and 12.5% of the samples in the first and second intervals, respectively. Foreign body reaction was observed in only 5% of the samples. The quality of regenerated bone was immature, mixed and lamellar in 54.5%, 15.9% and 4.5% of the samples, respectively. The rate of allograft resorption was the highest and lowest in the CenoBone and Grafton samples, respectively. The mean amount of regenerated bone was higher in areas containing Grafton; however, the differences were not statistically significant.

CONCLUSION

Despite the differences in the numerical values of bone regeneration, there were no statistically significant differences in bone generation among the material groups, and allografts manufactured in Iran can be suitable alternatives to Grafton with the same good properties. Further studies are necessary to clarify the efficacy of these allografts.

Bone Ceramic® at Implants Installed Immediately into Extraction Sockets in the Molar Region: An Experimental Study in Dogs

PURPOSE

The aim of this paper was to study the healing of 1-1.4 mm wide buccal defects at implants placed immediately into extraction sockets (IPIES) filled with a mixture of synthetic hydroxyapatite (HA) 60% and beta-tricalciumphosphate (TCP) 40% or left with the clot alone and both covered with collagen membranes.

MATERIAL AND METHODS

Eight Labrador dogs were used and implants were placed immediately into the extraction sockets of the first molar bilaterally. A mixture of synthetic HA 60% and beta-TCP 40% at the test or the clot alone at the control sites were used to fill the defects. All surgical sites were subsequently covered by a resorbable collagen membrane and a non-submerged healing was allowed. After 4 months, the animals were euthanized, biopsies harvested and processed for histomorphometric analysis.

RESULTS

At the time of installation, residual buccal defects occurred that were 1.1 mm and 1.4 mm wide and 3 mm and 4 mm deep at the control and test sites, respectively. After 4 months of healing, the top of the bony crest and the coronal level of osseointegration were located respectively at 0.1 ± 1.8 mm and 1.5 ± 1.8 mm at the test, and 0.6 ± 1.6 mm and 1.2 ± 0.7 mm at the control sites apically to the implant shoulder. Bone-to-implant contact at the buccal aspect was 34.9 ± 25.9% and 36.4 ± 17.3% at the test and control sites, respectively. No statistically significant differences were found between test and control sites for any of the variables analyzed at the buccal aspects.

CONCLUSIONS

The use of a mixture of synthetic HA 60% and beta-TCP 40% to fill residual buccal defects 1-1.4 mm wide at IPIES did not improve significantly the results of healing.

Ectopic osteoid and bone formation by three calcium-phosphate ceramics in rats, rabbits and dogs

Calcium phosphate ceramics with specific physicochemical properties have been shown to induce de novo bone formation upon ectopic implantation in a number of animal models. In this study we explored the influence of physicochemical properties as well as the animal species on material-induced ectopic bone formation. Three bioceramics were used for the study: phase-pure hydroxyapatite (HA) sintered at 1200°C and two biphasic calcium phosphate (BCP) ceramics, consisting of 60 wt.% HA and 40 wt.% TCP (β-Tricalcium phosphate), sintered at either 1100°C or 1200°C. 108 samples of each ceramic were intramuscularly implanted in dogs, rabbits, and rats for 6, 12, and 24 weeks respectively. Histological and histomorphometrical analyses illustrated that ectopic bone and/or osteoid tissue formation was most pronounced in BCP sintered at 1100°C and most limited in HA, independent of the animal model. Concerning the effect of animal species, ectopic bone formation reproducibly occurred in dogs, while in rabbits and rats, new tissue formation was mainly limited to osteoid. The results of this study confirmed that the incidence and the extent of material-induced bone formation are related to both the physicochemical properties of calcium phosphate ceramics and the animal model.

Occlusive barriers in combination with particulate Bio-Oss® graft: a pilot study on rabbit calvaria

The aim of this study was to histologically evaluate the potential for vertical bone augmentation of the Bio-Oss® graft compared to a blood clot in conjunction with an occlusive barrier in the rabbit calvaria defect model. Metallic dome shaped barriers with 4.5 mm width and 3.5 mm height were positioned in six adult rabbit skulls. At the right side, the barrier was filled with Bio-Oss®, and the left side was filled with a blood clot. After a healing period of three months, the animals were sacrificed, and the samples were prepared for histological and histomorphometric analyses. The total mineralized area (TMA) as well as the newly formed bone (NBA) was calculated as the percentage of the bone augmentation inside the metallic barriers, and parametric statistical analysis was used to describe the findings. The samples with blood clots exhibited significantly less TMA formation than the Bio-Oss® group. However, the difference in the amount of NBA was not statistically significant. Furthermore, the Bio-Oss® specimens exhibited remaining graft particles within the sample. In conclusion, the barriers filled with Bio-Oss® exhibited significantly higher TMA than those with only blood clots, and the remaining Bio-Oss® particles were integrated into newly formed bone tissue to fill the spaces and promote a greater volume than the samples from the blood clot groups.

Bone formation with deproteinized bovine bone mineral or biphasic calcium phosphate in the presence of autologous platelet lysate: comparative investigation in rabbit

Bone substitutes alone or supplemented with platelet-derived concentrates are widely used to promote bone regeneration but their potency remains controversial. The aim of this study was, therefore, to compare the regenerative potential of preparations containing autologous platelet lysate (APL) and particles of either deproteinized bovine bone mineral (DBBM) or biphasic calcium phosphate (BCP), two bone substitutes with different resorption patterns. Rabbit APL was prepared by freeze-thawing a platelet suspension. Critical-size defects in rabbit femoral condyle were filled with DBBM or DBBM+APL and BCP or BCP+APL. Rabbits were sacrificed after six weeks and newly formed bone and residual implanted material were evaluated using nondemineralized histology and histomorphometry. New bone was observed around particles of all fillers tested. In the defects filled with BCP, the newly formed bone area was greater (70%; P < 0.001) while the residual material area was lower (60%; P < 0.001) than that observed in those filled with DBBM. New bone and residual material area of defects filled with either APL+DBBM or APL+BCP were similar to those observed in those filled with the material alone. In summary, osteoconductivity and resorption of BCP were greater than those of DBBM, while APL associated with either DBBM or BCP did not have an additional benefit.

Comparative, Histological and Histomorphometric Analysis of Three Anorganic Bovine Xenogenous Bone Substitutes: Bio-Oss, Bone-Fill and Gen-Ox Anorganic

INTRODUCTION

Anorganic bovine xenogenous grafts show the best performance as bone substitutes in implantodontics. Bio-Oss is the world's most widely used and investigated anorganic bone substitute. This article compares two anorganic bovine bone substitutes (Bone-Fill and Gen-Ox anorganic) with Bio-Oss.

MATERIALS AND METHODS

Eight New Zealand rabbits were implanted with 4 titanium cylinders randomly filled with Bio-Oss, Bone-Fill, Gen-Ox anorganic or a blood clot. Four animals were sacrificed after 8 weeks; 12 weeks later, the remaining four were sacrificed. The contents of the cylinders were removed, cut and stained with HE before they were evaluated with an optical microscope. The samples were submitted to histomorphometry for analysis.

RESULTS

The bone formation with Bio-Oss at 8 weeks was 8.43 mm(2); at 12 weeks, it was 9.32 mm(2). The bone formation with Bone-Fill at 8 weeks was 7.24 mm(2); at 12 weeks, it was 9.01 mm(2). The bone formation with Gen-Ox anorganic at 8 weeks was 2.78 mm(2); at 12 weeks, it was 3.02 mm(2). The bone formation with the blood clot at 8 weeks was 0.65 mm(2); at 12 weeks, it was 0.63 mm(2).

CONCLUSION

Following this model, Bone-Fill was comparable to Bio-Oss and superior to Gen-Ox and blood clot.

Comparison of bone regeneration using three demineralized freeze-dried bone allografts: A histological and histomorphometric study in rabbit calvaria

Background:

It has been stated that the bone allografts from different tissue banks may lead to various amount of bone induction, so the aim of this study was to evaluate bone regeneration of three demineralized allografts both histologically and histomorphometrically in rabbits calvaria bone defects.

Materials and Methods:

In this double-blind randomized experimental animal study, 32 critical size defects (11-mm diameter) in the calvaria of 16 male New Zealand white rabbits were randomly filled with three demineralized freeze-dried bone allografts (DBM, CENOBONE, DEMBONE), while the nongrafted defect was regarded as control group. After 6 and 12 weeks of healing, the experimental animals were euthanized for specimen preparation. After histological evaluation, histomorphometric analysis was performed to quantify new bone formation and remained graft particles. The data were analyzed by one-way ANOVA with Tukey's ad-hoc test and t-test. (P < 0.05 was considered to be statistically significant).

Results:

Mean percentage of bone formation increased between two healing time, but it was not statistically significant in all groups except DBM which the bone formation significantly decreased (P = 0.04). There were not statistically significant differences between three allografts in remained particles and bone formation in both healing times and they could not induce significantly more bone formation than control group.

Conclusion:

Both test and control groups resulted in successful new bone formation. No difference was noted in bone formation and remained particles between three commercial bone allografts. Further studies in this issue may be needed.

Evaluation of healing processes of intraosseous defects with and without guided bone regeneration and platelet rich plasma. An animal study

BACKGROUND

In most cases, the natural healing of intrabony defects only leads to restoration of tissue continuity without differentiation and function. However, repair is not regarded to be an optimal treatment method, as confirmed in many clinical cases. Thus it is important to choose a surgical procedure which makes it possible to achieve restitution ad integrum of the bone structure. The choice of the GBR technique is crucial, in terms of the clinical conditions and limitations resulting from the use of a particular material.

OBJECTIVE

The objective of this study has been the analysis of effectiveness of selected surgical treatment techniques of intrabony defects in rabbits.

MATERIALS AND METHODS

Research was conducted on 36 white rabbits. The operation technique was a criterion of division into 3 groups: BG/BOC (Bio-Oss Collagen(®)+Bio-Gide Perio(®)), BOC/PRP (Bio-Oss Collagen(®)+PRP), C (control group). Qualitative and quantitative histopathological evaluation was carried out after 1, 3, 6 and 12 months.

RESULTS

The highest value of the bone surface area 31.9% (SD 1.8) was achieved in BOC/BG group three months after the implantation, while the lowest was revealed in C - group - 12.5% (SD 1.32) one month following the procedure.

CONCLUSIONS

Upon quantitative histological assessment, the bone tissue presented the most intensive osteogenesis within one month from the application of BOC/PRP, whereas this was observed after the application of BOC/BG in later stages. The application of two regenerative methods influenced the rate, quality and overall treatment of intraosseus defects.

Histological evaluation of Accell Connexus(®) and Bio-Oss(®) on quality and rate of bone healing: a single blind experimental study on rabbit's calvarium

OBJECTIVE

The objective of this study was to evaluate the effect of Accell Connexus(®) on the quality and rate of healing in experimental defects of rabbit calvarium compared to Bio-Oss®.

MATERIALS AND METHODS

Twelve 2.5-3.5 kg weighing New Zealand white rabbits were used. Three defects (3×6 mm) were created in the cranium of the animals subsequently filled with Accell Connexus(®), Bio-Oss® or served as controls. The animals were sacrificed four, six and eight weeks postoperatively and the histology blocks were studied in terms of inflammation, trabeculation thickness, bone type regeneration, foreign body and remained biomaterial by light microscope. The data were subject to Mann-Whitney U test.

RESULTS

Increased inflammatory reaction, foreign body reaction, delayed bone formation and lower rate of ossification were observed in DBM-filled defects compared to Bio-Oss® or controls. However, no significant differences were observed in bone formation between Bio-Oss®, Accell Connexus(®) and control specimens in the three time intervals. Furthermore, no significant differences were noted between Bio-Oss® and control groups.

CONCLUSION

Accell Connexus(®) showeda lower rate of ossification and bone healing compared to Bio-Oss® or controlgroups. Other studies in this field seem necessary.