Stabilization of Bio-Oss® particulates using photocurable hydrogel to enhance bone regeneration by regulating macrophage polarization

Bone substitutes are widely used in maxillofacial and oral surgeries. However, in clinical practice, bone substitutes with various forms, including separated particulates, powders, and blocks, have exhibited poor handling properties and space maintenance characteristics, resulting in long surgery procedures and unstable volume of the newly formed bone. Movable separated particulates with high stiffness have induced local inflammatory responses that hinder bone regeneration. The present study aimed to develop a new method to enhance the stability and operability of bone substitutes commonly used in dentistry by premixing with photocurable hydrogel GelMA. The GelMA-encapsulated particulate had a strong capacity to aggregate separated particulates and firmly attach to the host bone defect after photocuring compared to particulates alone. Additionally, macrophages at the surface of the GelMA-stabilized particulates tended to present a more M2-like phenotype than those at the surface of Bio-Oss^®, leading to more MMR⁺ multinucleated giant cell formation and the induction of blood vessel invasion and new bone formation. In conclusion, this hydrogel-coated bone substitute strategy facilitates bone regeneration with increased operability, a stable volume of osteogenic space, and a favorable osteogenic microenvironment, indicating its potential value in the field of maxillofacial and oral surgeries when bone substitutes are needed.

Characterization of a cotton-wool like composite bone graft material

Bone graft materials are applied in patients to augment bone defects and enable the insertion of an implant in its ideal position. However, the currently available augmentation materials do not meet the requirements of being completely resorbed and replaced by new bone within 3 to 6 months. A novel electrospun cotton-wool like material (Bonewool^®, Zurich Biomaterials LLC, Zurich, Switzerland) consisting of biodegradable poly(lactic-co-glycolic) acid (PLGA) fibers with incorporated amorphous ß-tricalcium phosphate (ß-TCP) nanoparticles has been compared to a frequently used bovine derived hydroxyapatite (Bio-Oss^®, Geistlich Pharma, Wolhusen, Switzerland) in vitro. The material composition was determined and the degradation behavior (calcium release and pH in different solutions) as well as bioactivity has been measured. Degradation behavior of PLGA/ß-TCP was generally more progressive than for Bio-Oss^®, indicating that this material is potentially completely resorbable. Graphical abstract.

Biocompatibility of mesoporous SBA-16/hydroxyapatite nanocomposite and dentin demineralized particles on human dental pulp stem cells

In the present work, a biomaterial (SBA-16/HA) based on the growth of hydroxyapatite (HA) particles within an organized silica structure SBA-16 (Santa Barbara Amorphous-16) was developed to evaluate its application to act as a porous microenvironment promoting attachment and viability of human dental pulp stem cells of healthy deciduous teeth (SHED). First, SHED were isolated and their phenotypes were evaluated by flow cytometry. The samples of SBA-16/HA were characterized by X-ray diffraction (XRD), small and wide angle X-ray scattering (SWAXS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) equipped with energy dispersive spectra detector (EDS). Afterward, cells were cultured in the eluates of the above-mentioned biomaterial aged for 24 hr, 7. and 14 days. Bio-Oss® and dentin particles are involved for comparison and cells are cultured in the eluates of these two materials also. Thiazolyl Blue Tetrazolium bromide assay-MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide assay) was used for the determination of cell viability. The results obtained by all aforementioned characterization methods of SBA-16/HA, revealed a uniform spherical mesoporous structure, an intrinsic characteristic of this material. This material displayed excellent biocompatibility on SHEDs, and even proliferative potential, indicating that SBA-16/HA could potentially serve as a suitable substrate for bone regeneration. Contrary to SBA-16/HA, dentin particles showed low cytotoxicity at all time points, compared to control and Bio-Oss®groups. Our results substantiate the idea that SBA-16/HA has a beneficial effect on SHEDs, thus paving the way toward developing new material for bone replacement.

Comparison of the performances of low-crystalline carbonate apatite and Bio-Oss in sinus augmentation using three-dimensional image analysis

BACKGROUND

In locations where the alveolar bone height is low, such as at the maxillary molars, implant placement can be difficult, or even impossible, without procedures aimed at generating new bone, such as sinus lifts. Various types of bone graft materials are used after a sinus lift. In our study, a three-dimensional image analysis using a volume analyzer was performed to measure and compare the volume of demineralized bovine bone mineral (Bio-Oss®) and carbonate apatite (Cytrans®) after a sinus lift, as well as the amount of bone graft material resorption. Patient data were collected from cone-beam computed tomography images taken before, immediately following, and 6 months after the sinus lift. Using these images, both the volume and amount of resorption of each bone graft material were measured using a three-dimensional image analysis system.

RESULTS

The amount of bone resorption in the Bio-Oss®-treated group was 25.2%, whereas that of the Cytrans®-treated group was 14.2%. A significant difference was found between the two groups (P < 0.001).

CONCLUSIONS

Our findings indicate that the volume of bone resorption was smaller in the Cytrans®-treated group than in the Bio-Oss®-treated group, suggesting that Cytrans® is more promising for successful implant treatments requiring a sinus lift.

Histological Evaluation of the Healing Process of Various Bone Graft Materials after Engraftment into the Human Body

The purpose of this study was to measure the level of new bone formation induced by various bone graft materials to provide clinicians with more choices. The samples were divided into three groups: group 1 (n = 9: allograft + xenograft, DBX^®, San Francisco, CA, USA + Bio-Oss^®, Princeton, NJ, USA), group 2 (n = 10: xenograft, Bio-Oss^®), and group 3 (n = 8: autogenous tooth bone graft, AutoBT^®, Korea Tooth Bank, Seoul, Korea). The average duration of evaluation was 9.56, 2.50, and 3.38 months, respectively. A tissue sample was taken from 27 patients during the second implant surgery. New bone formation was measured via histomorphometry, using a charge-coupled device camera, adaptor, and image analysis software. Total bone area, total area, and ((total bone area/total area) × 100) was measured to determine the extent of new bone formation. The mean value of the total bone area was 152,232.63 μm²; the mean value of the total area was 1,153,696.46 μm²; and the mean total bone area/total area ratio was 13.50%. In each comparison, there was no significant difference among the groups; no inflammation or complications were found in any of the groups. AutoBT^®, an autogenous tooth bone graft, resulted in a level of bone formation similar to that using allografts and xenografts.

Effect of rhBMP-2 Immobilized Anorganic Bovine Bone Matrix on Bone Regeneration

Anorganic bovine bone matrix (Bio-Oss®) has been used for a long time for bone graft regeneration, but has poor osteoinductive capability. The use of recombinant human bone morphogenetic protein-2 (rhBMP-2) has been suggested to overcome this limitation of Bio-Oss®. In the present study, heparin-mediated rhBMP-2 was combined with Bio-Oss® in animal experiments to investigate bone formation performance; heparin was used to control rhBMP-2 release. Two calvarial defects (8 mm diameter) were formed in a white rabbit model and then implanted or not (controls) with Bio-Oss® or BMP-2/Bio-Oss®. The Bio-Oss® and BMP-2/Bio-Oss® groups had significantly greater new bone areas (expressed as percentages of augmented areas) than the non-implanted controls at four and eight weeks after surgery, and the BMP-2/Bio-Oss® group (16.50 ± 2.87 (n = 6)) had significantly greater new bone areas than the Bio-Oss® group (9.43 ± 3.73 (n = 6)) at four weeks. These findings suggest that rhBMP-2 treated heparinized Bio-Oss® markedly enhances bone regeneration.

A Bone Sample Containing a Bone Graft Substitute Analyzed by Correlating Density Information Obtained by X-ray Micro Tomography with Compositional Information Obtained by Raman Microscopy

The ability of bone graft substitutes to promote new bone formation has been increasingly used in the medical field to repair skeletal defects or to replace missing bone in a broad range of applications in dentistry and orthopedics. A common way to assess such materials is via micro computed tomography (µ-CT), through the density information content provided by the absorption of X-rays. Information on the chemical composition of a material can be obtained via Raman spectroscopy. By investigating a bone sample from miniature pigs containing the bone graft substitute Bio Oss^®, we pursued the target of assessing to what extent the density information gained by µ-CT imaging matches the chemical information content provided by Raman spectroscopic imaging. Raman images and Raman correlation maps of the investigated sample were used in order to generate a Raman based segmented image by means of an agglomerative, hierarchical cluster analysis. The resulting segments, showing chemically related areas, were subsequently compared with the µ-CT image by means of a one-way ANOVA. We found out that to a certain extent typical gray-level values (and the related histograms) in the µ-CT image can be reliably related to specific segments within the image resulting from the cluster analysis.

Bio-Oss(®) for delayed osseointegration of implants in dogs: a histological study

We evaluated the effects of Bio-Oss® (a natural bone substitute derived from the mineral portion of bovine bone) on delayed osseointegration of implants. The bilateral third and fourth mandibular premolars of 4 adult, healthy, male and female dogs were extracted. We randomly selected 2 extraction sockets in each dog to be filled with Bio-Oss® (the experimental group); the other 2 extraction sockets, which were not treated, served as controls. Dental implants were inserted into the alveolar bone of the experimental group and the control group 3 months after insertion of the Bio-Oss®. The osteogenic activity in the bone around the implants was assessed by evaluating the histological morphology and estimating histomorphometric variables at 3 and 6 months after delayed implantation. After 3 months, Goldner's trichrome staining analysis showed that the rate of content between the bone and the implant and the mineralised area of bone around the implant were significantly higher in the experimental group (76%(9%) and 69.5% (9.6%), respectively) than those in the control group (56.1% (8.2%) and 52.8% (7.3%), respectively, p=0.003 and 0.000). However, the 2 groups did not differ significantly at 6 months. Fluorescence microscopy showed that the mean rates of mineralisation of the bony tissue around the implant in the experimental group at months 3 and 6 were 6.8 (0.4) μm and 8.4 (0.8) μm, respectively, which were significantly higher than those in the control group (p=0.000 and 0.03). These data indicate that putting Bio-Oss® into the extraction sockets can promote osseointegration after delayed implantation, and may be a promising option for clinical use.

Alveolar bone grafts distal to the lower second molar

INTRODUCTION

This paper presents case and technique reports on the use of Bio-Oss® and Bio-Gide® implantable material for the establishment of a mineral and protein scaffold for reconstruction of the distal alveolus of the lower distal second molar (lower dM2).

METHODS

Such 'alveolar bone grafts' were undertaken immediately following the removal of deep horizontal or mesio-angular impacted wisdom teeth, and which had the following associations. 1) Partial eruption of the third molar, 2) Preoperative radiographic (OPG) evidence of loss of bone height (≥3mm) below the distal Cemento-Enamel Junction (CEJ) of the lower dM2, and 3) Patient aged ≥26 years of age. Following a presentation of radiographs (in three patients) taken preoperatively and postoperatively (at ∼6 months), a brief description of the technique is offered as well as a brief literature review on the subject.

CONCLUSION

The author suggests that for older patients (≥26 years) were there is the presence of partially exposed deep mesio-angular or horizontal impacted wisdom teeth, and which are associated with the radiographic appearance of bone loss to the distal surface of the lower second molar tooth, then alveolar bone grafting utilising Bio-Oss® and Bio-Gide® is an effective and stable treatment option to prevent development of periodontal pocketing in the area. The author advises for more guided and systematised study in this area.