Comparative Evaluation of Osteogenic Potential of Conventional Glass-ionomer Cement with Chitosan-modified Glass-ionomer and Bioactive Glass-modified Glass-ionomer Cement An In vitro Study

Chitosan-Reinforced Gelatin Microspheres-Modified Glass Ionomer Cement (GIC): A Novel Bone Alloplast Graft Material Synthesis and an In Vivo Analysis

Aim and objective The study aimed to assess and evaluate the efficacy of glass ionomer modified with chitosan-reinforced gelatin microspheres on bone formation. Materials and methods  The study involved three groups: Group I comprised plain glass ionomer cement; Group II comprised glass ionomer cement/gelatin (70:30 wt%); in Group III, glass ionomer cement/gelatin/chitosan (70:30%) scaffold were made into discs; the gelatin microspheres were synthesized by oil emulsion method. The synthesized scaffold was subjected to the following in vitro testing, Instron Universal Testing Machine (UTM), U3000, (Instron Corporation, Norwood, Massachusetts, United States) to assess compressive strength, scanning electron microscope (SEM) examination, and biocompatibility testing using hemocompatibility assay. The material was then tested in vivo; male Wistar albino rats, a total of nine animals, were utilized for this purpose. Three animals were used in each group; a femoral defect model was the model of choice for the experiment and the animals were observed for a period of four weeks, following which the animals were sacrificed and sent for histopathological analysis. Results The compression testing was carried out using UTM; test group I was 33 MPa, test group II was 2.3 MPa, and test group III was 25.75 MPa. SEM (JSM-IT800 Schottky Field Emission NANO SEM (JEOL, Tokyo, Japan)) analysis was done to observe the porosity of the fabricated scaffold with the average measurement of 0.12 ± 0.2 μm in test group II and 0.29 ± 0.4 μm in test group III. Hemocompatibility reports noted 0.4-0.8% lysis for the synthesized scaffolds. Histopathology staining of the femur defects showed that group III favoured bone formation. One-way analysis of variance (ANOVA) and post hoc Bonferroni test was done on the data. The optical density values of the alizarin red stained slide showed statistical significance for group III. Conclusion In conclusion, the synthesized scaffolds are biocompatible, distribution of porosity and pore characteristics in the glass ionomer cement/gelatin/chitosan group is better than that of the glass ionomer cement/gelatin group. The glass ionomer cement/gelatin/chitosan group had better compressive strength and induced more bone formation compared to the other test group and the control. Thus, the novel glass ionomer modified with chitosan-reinforced gelatin microspheres has optimal properties to be used as a bone graft material.

Chitosan Resin-Modified Glass Ionomer Cement Containing Epidermal Growth Factor Promotes Pulp Cell Proliferation with a Minimum Effect on Fluoride and Aluminum Release

The development of biomaterials that are able to control the release of bioactive molecules is a challenging task for regenerative dentistry. This study aimed to enhance resin-modified glass ionomer cement (RMGIC) for the release of epidermal growth factor (EGF). This RMGIC was formulated from RMGIC powder supplemented with 15% (w/w) chitosan at a molecular weight of either 62 or 545 kDa with 5% bovine serum albumin mixed with the same liquid component as the Vitrebond. EGF was added while mixing. ELISA was used to determine EGF release from the specimen immersed in phosphate-buffered saline at 1 h, 3 h, 24 h, 3 d, 1 wk, 2 wks, and 3 wks. Fluoride and aluminum release at 1, 3, 5, and 7 d was measured by electrode and inductively coupled plasma optical emission spectrometry. Pulp cell viability was examined through MTT assays and the counting of cell numbers using a Coulter counter. The RMGIC with 65 kDa chitosan is able to prolong the release of EGF for significantly longer than RMGIC for at least 3 wks due to its retained bioactivity in promoting pulp cell proliferation. This modified RMGIC can prolong the release of fluoride, with a small amount of aluminum also released for a limited time. This biomaterial could be useful in regenerating pulp-dentin complexes.

Comparison of Antibacterial Activity, Cytotoxicity, and Fluoride Release of Glass Ionomer Restorative Dental Cements in Dentistry

BACKGROUND This study aimed to compare the antibacterial activity, cytotoxicity, and fluoride release of 4 different glass ionomer cements (GIC). MATERIAL AND METHODS A total of 200 samples were prepared: Riva Silver, a silver-reinforced GIC; Equia Forte HT, a glass hybrid GIC; ChemFil Rock, a zinc-added GIC; and Ketac™ Molar Easymix. Using the agar diffusion test for antibacterial activity, 30 samples from each group were analyzed for Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces naeslundii. The areas around the samples where no bacterial growth occurred were digitally measured and recorded. For cytotoxicity analysis, the WST-1 test was performed on 10 samples from each group using the L929 mouse fibroblast cell line. The fluoride release property was evaluated using an ion-selective electrode method on 10 samples from each group. RESULTS The group that used Ketac™ Molar Easymix showed the lowest antibacterial activity against S. mutans, L. acidophilus, and A. naeslundii. In all 3 days of cytotoxicity testing, the group that used Riva Silver was found to be the least toxic material, while the group that used ChemFil Rock did not have viable cells after the 1st day. In all 4 materials, fluoride release values gradually increased since the first day, with Ketac™ Molar Easymix having the highest fluoride release. CONCLUSIONS Of all the GICs tested, Ketac™ Molar Easymix demonstrated the least antibacterial activity despite having the highest fluoride release, while Riva Silver was found to be the least cytotoxic material.

Dual-Functional Polyetheretherketone Surface with an Enhanced Osteogenic Capability and an Antibacterial Adhesion Property In Vitro by Chitosan Modification

A chitosan layer was covalently bonded to a polyetheretherketone (PEEK) surface using a simple facile self-assembly method to address inadequate biological activity and infection around the implant. The surface characterization, layer degradation, biological activity, and antibacterial adhesion properties of chitosan-modified PEEK (PEEK-CS) were studied. Through chitosan grafting, the surface morphology changed, the surface roughness increased, and the contact angle decreased significantly. PEEK-CS boosted cell adhesion, proliferation, increased alkaline phosphate activity, extracellular matrix mineralization, and expression of osteogenic genes. PEEK-CS demonstrated less adhesion to Porphyromonas gingivalis as well as less bacterial adhesion to P. gingivalis and Streptococcus mutans. According to our findings, chitosan modification significantly improved the osteogenic ability and antibacterial adhesion of PEEK in vitro.