A clinical report of bone regeneration in maxillofacial surgery using bonelike synthetic bone graft

Randomized clinical study of injectable dextrin-based hydrogel as a carrier of a synthetic bone substitute

OBJECTIVES

This study aimed to improve the performance and mode of administration of a glass-reinforced hydroxyapatite synthetic bone substitute, Bonelike by Biosckin® (BL®), by association with a dextrin-based hydrogel, DEXGEL, to achieve an injectable and moldable device named DEXGEL Bone.

METHODS

Twelve participants requiring pre-molar tooth extraction and implant placement were enrolled in this study. BL® granules (250-500 µm) were administered to 6 randomized participants whereas the other 6 received DEXGEL Bone. After 6 months, a bone biopsy of the grafted area was collected for histological and histomorphometric evaluation, prior to implant placement. The performance of DEXGEL Bone and BL® treatments on alveolar preservation were further analyzed by computed tomography and Hounsfield density analysis. Primary implant stability was analyzed by implant stability coefficient technique.

RESULTS

The healing of defects was free of any local or systemic complications. Both treatments showed good osseointegration with no signs of adverse reaction. DEXGEL Bone exhibited increased granule resorption (p = 0.029) accompanied by a tendency for more new bone ingrowth (although not statistically significant) compared to the BL® group. The addition of DEXGEL to BL® granules did not compromise bone volume or density, being even beneficial for implant primary stability (p = 0.017).

CONCLUSIONS

The hydrogel-reinforced biomaterial exhibited an easier handling, a better defect filling, and benefits in implant stability.

CLINICAL RELEVANCE

This study validates DEXGEL Bone safety and performance as an injectable carrier of granular bone substitutes for alveolar ridge preservation.

TRIAL REGISTRATION

European Databank on Medical Devices (EUDAMED) No. CIV-PT-18-01-02,705; Registo Nacional de Estudos Clínicos, RNEC, No. 30122.

Regeneration of critical-sized defects, in a goat model, using a dextrin-based hydrogel associated with granular synthetic bone substitute

The development of injectable bone substitutes (IBS) have obtained great importance in the bone regeneration field, as a strategy to reach hardly accessible defects using minimally invasive techniques and able to fit to irregular topographies. In this scenario, the association of injectable hydrogels and bone graft granules is emerging as a well-established trend. Particularly, in situ forming hydrogels have arisen as a new IBS generation. An in situ forming and injectable dextrin-based hydrogel (HG) was developed, aiming to act as a carrier of granular bone substitutes and bioactive agents. In this work, the HG was associated to a granular bone substitute (Bonelike^®) and implanted in goat critical-sized calvarial defects (14 mm) for 3, 6 and 12 weeks. The results showed that HG improved the handling properties of the Bonelike^® granules and did not affect its osteoconductive features, neither impairing the bone regeneration process. Human multipotent mesenchymal stromal cells from the umbilical cord, extracellular matrix hydrolysates and the pro-angiogenic peptide LLKKK18 were also combined with the IBS. These bioactive agents did not enhance the new bone formation significantly under the conditions tested, according to micro-computed tomography and histological analysis.

In vivo systemic toxicity assessment of an oxidized dextrin-based hydrogel and its effectiveness as a carrier and stabilizer of granular synthetic bone substitutes

The worldwide incidence of bone disorders is raising, mainly due to aging population. The lack of effective treatments is pushing the development of synthetic bone substitutes (SBSs). Most ceramic-based SBSs commercially available display limited handling properties. Attempting to solve these issues and achieve wider acceptance by the clinicians, granular ceramics have been associated with hydrogels (HGs) to produce injectable/moldable SBSs. Dextrin, a low-molecular-weight carbohydrate, was used to develop a fully resorbable and injectable HG. It was first oxidized with sodium periodate and then cross-linked with adipic acid dihydrazide. The in vivo biocompatibility and safety of the dextrin-based HG was assessed by subacute systemic toxicity and skin sensitization tests, using rodent models. The results showed that the HG did not induce any systemic toxic effect, skin reaction, or genotoxicity, neither impaired the bone repair/regeneration process. Then, the HG was successfully combined with granular bone substitute, registered as Bonelike (250-500 μm) to obtain a moldable/injectable SBS, which was implanted in tibial fractures in goats for 3 and 6 weeks. The obtained results showed that HG allowed the stabilization of the granules into the defect, ensuring effective handling, and molding properties of the formulation, as well as an efficient cohesion of the granules. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1678-1689, 2019.

Comparison of the effect of hemihydrate calcium sulfate granules and Cerabone on dental socket preservation: An animal experiment

Background. Early bone loss due to tooth extraction can be significantly reduced by socket preservation. The aim of this study was to compare the in vivo effects of hemihydrate calcium sulfate granules (an alloplastic material) and Cerabone (a bovine-derived xenograft) on socket preservation in dogs. Methods. Six male Mongrel dogs were randomly divided into 2 groups (n=3) for sacrificing and histological evaluation 4 and 8 weeks after a surgery. The second and third premolars on both sides of the lower jaw were extracted surgically. The sockets on one side were filled with Cerabone, and with calcium sulfate on the opposite side. In the slides, the ratio of the area of newly formed bone to the area of the entire cavity, and the ratio of the area of fibrous connective tissue to the area of the entire cavity were measured. The presence of inflammation was also examined. Wilcoxon signed-rank test, Sign test and McNemar test were used for statistical analyses (ɑ=0.05). Results. The means of new bone proportion were 11% and 8% for Cerabone and calcium sulfate, respectively (P=0.58). The means of connective tissue proportion were 29% and 33% for Cerabone and calcium sulfate, respectively (P=0.72). No inflammatory cells were observed in the Cerabone group, although 50% of the samples in the calcium sulfate group showed inflammation (P=0.50). Conclusion. The effects of calcium sulfate and Cerabone on socket preservation in dogs on bone formation, fibrous connective tissue and inflammation levels were not significantly different at 4- and 8-week postoperative intervals.

Application of Bonelike® as synthetic bone graft in orthopaedic and oral surgery in veterinary clinical cases

Autologous bone remains the gold standard grafting substrate for bone fusions used for small gaps and critical defects. However, significant morbidity is associated with the harvesting of autologous bone grafts and, for that reason, alternative bone graft substitutes have been developed. In the present case series, a glass-reinforced hydroxyapatite synthetic bone substitute, with osteoinductive and osteoconductive proprieties, was applied. This synthetic bone substitute comprises the incorporation of P2O5-CaO glass-based system within a hydroxyapatite matrix, moulded into spherical pellets with 250-500 μm of diameter. A total of 14 veterinary clinical cases of appendicular bone defects and maxillary / mandibular bone defects are described. In all clinical cases, the synthetic bone substitute was used to fill bone defects, enhancing bone regeneration and complementing the recommended surgical techniques. Results demonstrated that it is an appropriate synthetic bone graft available to be used in veterinary patients. It functioned as a space filler in association with standard orthopaedic and odontological procedures of stabilization, promoting a faster bone fusion without any local or systemic adverse reactions. This procedure improves the animals' quality of life, decreasing pain and post-operative recovery period, as well as increasing bone stability improving positive clinical outcomes.

Inflammatory response to dextrin-based hydrogel associated with human mesenchymal stem cells, urinary bladder matrix and Bonelike® granules in rat subcutaneous implants

Increasing relevance has been attributed to hydrogels due to their ability to provide an extracellular matrix (ECM)-like environment for cellular adhesion and proliferation, acting as mechanical scaffolds for tissue remodeling or as delivery matrices. In vivo biocompatibility of a hybrid dextrin hydrogel produced from oxidized dextrin and adipic acid dihydrazide and its combinations with human mesenchymal stem cells (hMSCs), ECM from a porcine bladder (urinary bladder matrix) and ceramic granules (Bonelike^®), was evaluated following ISO 10993 after subcutaneous implantation in a rat model. Histological analysis after 3 and 15 d showed typical acute and chronic inflammatory responses, respectively, with a more severe reaction exhibited whenever the ceramic granules were present. However, the dextrin hydrogel was able to stabilize granules in the implant site. Dextrin hydrogel was scored as slight irritant after 3 d, similar to its combination with UBM, and as non-irritant after 15 d. The presence of viable hMSCs in the subcutaneous tissue could be confirmed by the presence of anti-human nuclei antibody (HuNu⁺) cells. The production of growth factors and inflammatory and immunomodulatory cytokines by these cells was also quantified in peripheral blood confirming the successful encapsulation of hMSCs into the hydrogel matrix for cell survival promotion. The presence of hMSCs seemed to modulate the inflammatory response by accelerating its progression when compared to the acellular experimental groups. Dextrin hydrogel has proven to be a biocompatible multifunctional matrix for minimally invasive biomedical procedures, including orthopedic surgeries when associated with bone substitutes and also as a possible encapsulation matrix for cell-based therapies.

Treatment of a Large Cystic Lesion in Anterior Maxilla Using Glass Reinforced Hydroxyapatite – A Case Report

Jaw cysts are common lesions in the maxillofacial area. Their treatment varies from surgical enucleation alone to enucleation followed by bone grafting depending on the size of the lesion. Various bone substitutes ranging from autografts, allografts, xenografts and alloplasts have been tried and tested with varying degrees of success. Here, the author present a case report of large cystic lesion of anterior maxilla and its treatment using a glass reinforced hydroxyapatite composite (Bonelike®) following enucleation. One year follow up demonstrated satisfactory clinical and radiological treatment outcomes.Keywords: Jaw cyst, enucleation, defect filling, alloplast, Bonelike®, bone grafts.

Guided Bone Regeneration Using Glass-Reinforced Hydroxyapatite and Collagen Membrane in the Treatment of Peri-Implantitis

Implant therapy has provided the clinician a wide variety of treatment options with respect to the replacement of missing natural teeth. With more number of dentists practicing implant dentistry, one is likely to be presented with peri-implantitis and implant related failures in day to day practice. Peri-impant mucositis can be reversed by elimination of the biofilm but peri-implantitis which results in bone loss and subsequent exfoliation of the implant if left unattended have to be treated using a regenerative approach in addition to conventional non surgical therapy. The present case demonstrates the guided bone regeneration procedure using a glass-reinforced HA and collagen membrane in the treatment of an intrabony defect around the implant. Nine months post operative radiograph revealed complete resolution of the defect. This novel composite alloplast shows promise in treating such lesions.Keywords: Peri-implantitis, Guided bone regeneration, Alloplast, Dental implant, Bone graft, Collagen membrane, Implant decontamination.

Evaluation of the osteoconductive potential of bone substitutes embedded with schneiderian membrane- or maxillary bone marrow-derived osteoprogenitor cells

AIM

Sinus augmentation procedures commonly employ osteoconductive scaffolding materials to stimulate and support bone formation. The aim of this study was to develop a simple screening methodology for the evaluation of the osteoconductive potential of various bone graft materials prior to clinical use.

MATERIALS AND METHODS

Materials tested were Bio-Oss, Bi-Ostetic, OraGraft, and ProOsteon. These Simple and composite bone substitutes were embedded with osteoprogenitor cells derived from either the human maxillary sinus schneiderian membrane (hMSSM) or from maxillary tuberosity bone marrow and then monitored both in vitro and in vivo.

RESULTS

Cell adherence and proliferation was most pronounced in OraGraft, followed by ProOsteon. In vivo bone formation, within the bone graft, was also observed, with most marked results in OraGraft and ProOsteon grafts.

CONCLUSIONS

The proposed osteoconductivity testing method proved simple, informative, and reliable for the purpose of screening candidate biomaterials for sinus lifting or sinus augmentation.

Osteogenesis of mineralized collagen bone graft modified by PLA and calcium sulfate hemihydrate: in vivo study

In this study, the biocompatibility and bone regeneration performance of nano-hydroxyapatite/collagen/poly(L-lactide) (nHAC/PLA) and nano-hydroxyapatite/collagen/calcium sulfate hemihydrate (nHAC/CSH) as bone-filling materials were evaluated and compared in a critical box-shaped defect model in the mandible of the rabbits. In vivo results indicated that there was significant difference in early bone remodeling between two types of bone substitutes. nHAC/PLA has shown excellent biocompatibility, but no adequate handling properties. The addition of CSH to nHAC provided better manipulability compared to nHAC/PLA. Furthermore, nHAC/CSH possesses superior properties in restoring critical-sized bone defects of maxillofacial region at the early stage of remodeling over nHAC/PLA. Our results suggested that nHAC/CSH could be an alternative to the conventionally used bone tissue engineering materials.

A glass-reinforced hydroxyapatite and surgical-grade calcium sulfate for bone regeneration: In vivo biological behavior in a sheep model

A glass-reinforced hydroxyapatite (HA) composite (Bonelike®) was developed for bone grafting. This biomaterial is composed of a modified HA matrix with α- and β-tricalcium phosphate secondary phases, resulting in higher solubility than single HA type of materials. Several in vitro and in vivo studies demonstrated that Bonelike® has a highly bioactive behavior, which was also confirmed by employing granular forms of this biomaterial in orthopedics and dental applications. However, a fast consolidation vehicle was needed to promote the fixation of Bonelike® granules if applied in larger defects or in unstable sites. Surgical-grade calcium sulfate (CS), which is widely recognized as a well-tolerated and inexpensive bone graft material, was the chosen vehicle to improve the handling characteristics of Bonelike® as it can be used in the form of a powder that is mixed with a liquid to form a paste that sets in situ. After application in non-critical monocortical defects in sheep, histological, and scanning electron microscopy evaluations demonstrated that Bonelike® associated to CS functioned as a very satisfactory scaffold for bone regeneration as it achieved synchronization of the ingrowing bone with biomaterial resorption and subsequent preservation of the bone graft initial volume. Therefore, our results indicate that CS is an effective vehicle for Bonelike® granules as it facilitates their application and does not interfere with their proven highly osteoconductive properties. In the opposite way, the incorporation of Bonelike® improves the bone regeneration capabilities of CS.

Application of Glass Reinforced Hydroxyapatite Composite in the Treatment of Human Intrabony Periodontal Angular Defects – Two Case Reports

Bony defects caused by periodontitis are often treated by regenerative therapy using autografts and/or allografts. Alloplasts such as hydroxyapatite or ceramics and bioactive glasses are used as osteoconductive materials that serve as scaffold for new bony ingrowth. The purpose of this study was to ascertain the possible regenerative capability of glass reinforced hydroxyapatite (Bonelike¬)¬¬¬ an osteoconductive synthetic graft in the treatment of human periodontal intrabony angular defects. The material was placed in 2 defects in 2 individual patients and clinical parameters such as probing depth (PD) and clinical attachment level (CAL) have been included. Bone fill was determined using an intra oral periapical radiograph (IOPA) and Autocad Software. After 3 months implantation period, there was an improvement in CAL and reduction in PD along with bone fill was observed.

Growth and phenotypic expression of human endothelial cells cultured on a glass-reinforced hydroxyapatite

Glass-reinforced hydroxyapatite composites (GR-HA) are bone regenerative materials that are characterized by their increased mechanical properties, when compared to synthetic hydroxyapatite. Bonelike is a GR-HA that is a result of the addition of a CaO-P(2)O(5) based glass to a HA matrix. This biomaterial has been successfully applied in clinical bone regenerative applications. This work aims to evaluate the ability of Bonelike to support the adhesion, proliferation and phenotypic expression of human endothelial cells, aiming to establish new bone tissue engineering pre-endothelialization strategies. Bonelike discs, regardless of being submitted to a pre-immersion treatment with culture medium, were seeded with first passage human umbilical vein endothelial cells, and characterized regarding proliferation and differentiation events. Pre-immersed Bonelike allowed the adhesion, proliferation and phenotype expression of endothelial cells. Seeded materials presented positive immunofluorescent staining for PECAM-1 and a tendency for the formation of cord-like arrangements under angiogenesis-stimulating conditions, although, compared to standard culture plates, a slight decreased cell growth was observed. In this way, Bonelike may be a suitable candidate for pre-endothelialization approaches in bone tissue engineering applications.