Comparative Evaluation of Bone Repair with Four Different Bone Substitutes in Critical Size Defects

This study evaluated the osteoconductive potential of four biomaterials used to fill bone defects. For this, 24 male Albino rabbits were submitted to the creation of a bilateral 8 mm calvarial bone defect. The animals were divided into four groups—bovine hydroxyapatite, Bio-Oss® (BIO); Lumina-Bone Porous® (LBP); Bonefill® (BFL); and an alloplastic material, Clonos® (CLN)—and were euthanized at 14 and 40 days. The samples were subjected to histological and histometric analysis for newly formed bone area. Immunohistochemical analysis for Runt-related transcription factor 2 (Runx2), vascular endothelial growth factor (VEGF), and osteocalcin (OC) was performed. After statistical analysis, the CLN group showed greater new bone formation (NB) in both periods analyzed (p<0.05). At 14 days, the NB showed greater values in BIO in relation to LBP and BFL groups; however, after 40 days, the LBP group surpassed the results of BIO (p<0.001). The immunostaining showed a decrease in Runx2 intensity in BIO after 40 days, while it increased for LBP (p<0.05). The CLN showed increased OC compared to the other groups in both periods analyzed (p<0.05). Therefore, CLN showed the best osteoconductive behavior in critical defects in rabbit calvaria, and BFL showed the lowest osteoconductive property.

Application of Solution Plasma Surface Modification Technology to the Formation of Thin Hydroxyapatite Film on Titanium Implants

Hydroxyapatite (HA) coatings on titanium implants enhance rapid bone formation around the implant due to their osteoconductive property. The present study aimed to achieve a thin and uniform HA film coating on titanium implants by solution plasma treatment (SPT). Commercially pure titanium and porous titanium disks were employed. A pulse plasma generator was used on the disks for 30 min. Morphologic and crystallographic features of the deposited films were examined by scanning electron microscopy (SEM) and X-ray diffractometry (XRD). To evaluate the wettability of the disks, water droplet (20 µL) surfaces were measured using a contact angle analyzer. The initial attachment of osteoblast-like cells (MC3T3E1) on the titanium substrates before and after solution plasma treatment was evaluated by counting the number of attached cells after incubation for 4 h. After immersion in the mineralizing solution for up to seven days, no crystals were observed on the polished-Ti surface. A more uniform and dense precipitation of round and grown crystals with diameters of approximately 1–5 µm was observed on Ti-SPT. XRD clearly showed that the precipitated crystals on titanium disks were HA. The contact angle of the polished-Ti increased with time (θ = 37°–51°). The surface of the Ti-SPT remained hydrophilic (θ ˂ 5°) after up to 30 days of aging. The number of attached cells on the Ti-SPT after aging for 30 days remained above 85% of that on the Ti-SPT without aging. SPT in a mineralizing solution can be used to acquire a homogenous precipitation of HA on porous-surfaced titanium implants.

Age-related changes in bone architecture

ABSTRACT Objective : to evaluate the histologic and morphometric characteristics of bone biopsies of the anterior iliac crest of patients of different age groups. Methods : we studied 30 bone samples from the iliac crest, using brightfield optical microscopy. We divided the samples by donors' age groups in three groups: Group 1 (n = 10), subjects aged between 25 and 39 years; Group 2 (n = 10), subjects aged between 40 and 64 years; Group 3 (n = 10), individuals aged 65 years and over. We randomly divided the samples into two sets with 15 specimens. In the first study segment (n = 15), we used histological to assess the osteogenic property of the graft, through the analysis of cell reserve in the periosteum, the number of osteocytes in the lacunae and the number of Haversian and Volkmann's canals. In the second study segment (n = 15), we investigated the morphology of osteoconductive property of the graft, through quantification of the trabecular meshwork (Vv) and trabecular area (Sv). Results : histologically, we observed degeneration of bone occurring with age, characterized by thinning of the periosteum, with gradual replacement of the steogenic layer by fibrous tissue, small amount of Haversian and Volkmann's canals, osteocyte lacunae voids and fine spongy bone trabeculae, allowing ample medullary space, usually occupied by fat cells and adipocytes. Morphologically, with respect to the quantification of the trabecular meshwork (Vv), we found statistically significant differences between Groups 1 and 3 and between Groups 2 and 3, with reduction of the trabecular meshwork of about 45% in the elderly over 65 years old ; there was no statistically significant difference between Groups 1 and 2. There was also no statistical difference between the Groups regarding Sv. Conclusion : the results of this experiment suggest that, in the elderly (over 65 years old), the osteogenic property of autologous bone graft decreases and the osteoconductive property is compromised.

Modulation of the osteoconductive property and immune response of poly(ether ether ketone) by modification with calcium ions

A Ca-modified PEEK facilitates osteoblastic cell proliferation and differentiation and shifts macrophage phenotype towards anti-inflammatory/wound healing type.

Calcium Phosphate Mineralized GBR Membranes: Preparation and Properties

The osteoconductive property of calcium phosphate (CaP) biomaterials allow attachment, proliferation, migration, and phenotypic expression of bone cells leading to formation of new bone. The purpose of research is to develop new method of mineralizing commercial GBR membranes with calcium phosphate (CaP) and determine cell response. Resolut Adapt LT (Gore-tex) composed of co-polymer PGA/TMC and Biomend Extend (Zimmer) composed of bovine collagen were used. Membranes were mineralized with CaP using precipitation and new microwave methods. The mineralized and non-mineralized membranes were characterized using SEM, EDS, XRD, FT-IR, and TGA. Cell response to mineralized and non-mineralized membranes was determined using human osteoblastlike cells (MG-63). Microwave method was more efficient in terms of amount of minerals incorporated with membranes and time required. SEM, EDS, and FT-IR identified carbonate apatite in the mineralized membranes. No significant difference in cell proliferation was observed between mineralized and non-mineralized membranes. Greater production of type 1 collagen was observed with CaP mineralized membranes.

Osteoconductivity of Titania Films Prepared by Electron-Cyclotron-Resonance Plasma Oxidation of Implant Titanium

Surface titanium oxide (TiO2) films were fabricated on implant titanium (Ti) at low temperatures by electron-cyclotron-resonance (ECR) plasma oxidation. The relationship among the oxidization conditions, crystal structure, morphology and osteoconductive property were investigated. Although crystallized TiO2 film was not prepared by thermal oxidation at 300°C, crystallized rutile-type TiO2 film was formed by ECR plasma oxidation at 300°C. Rough morphology was observed in the substrate surface oxidized by ECR plasma. Mixtures of octacalcium phosphate (OCP) and dicalcium phosphate dihydrate (DCPD) were observed after calcification. The XRD peak intensities of the OCP and DCPD formed on the ECR plasma oxidized Ti were larger than those of calcified on the thermal oxidized Ti. ECR plasma oxidation at low temperature would induce osteoconductive calcium phosphate on implant Ti.

Bioactive Glass Efficacy in the Periodontal Healing of Intrabony Defects in Monkeys

The purpose of this study was the histomorphologic analysis of the efficacy of bioactive glass particles with a narrow size range (Biogran) in the periodontal healing of 2-wall intrabony defects in monkeys. The 2-wall defects were made in the mesial area of the left and right second premolars of four monkeys, filled with gutta-percha and, after 15 days, they were debrided and either naturally filled with coagulum (control) or implanted with bioactive glass (test). In the control sites, the junctional epithelium migrated up to the base of the defect. The presence of newly formed cementum was more significant in the test defects. Both control and test sites showed newly formed bone at the base of the defect. The test defects presented foci of newly formed bone around and within the glass particles localized in the middle third, distant from the defect walls. Histologic analysis showed that the 300- to 355-µm bioactive glass particles aided new periodontal insertion. In conclusion, the tested bioactive glass had better healing potential than debridement only. The graft material showed a promising inhibition of apical migration of the junctional epithelium and greater cementum deposition on the radicular surface of the intrabony defects. The replacement of bioactive glass particles by new bone occurred due not only to an osteoconductive property, but also to an osteostimulatory capacity. Future investigations should evaluate this potential comparatively or together with other grafting materials, regenerative techniques and biological modifiers, as well as assess the longitudinal stability of the new attachment.