Allogenic vs. synthetic granules for bone tissue engineering: an in vitro study

Comparison of Osteoblastic Differentiation of Human Periodontal Ligament Stem Cells through Application of Two β-tricalcium Phosphate Products: An in vitro Study

Statement of the Problem

Osteoblastic differentiation of periodontal ligament stem cells (PLSCs) is essential for alveolar bone regeneration.

Purpose

The purpose of this study was to compare the potential of two β-tricalcium phosphate (βTCP) products to induce osteoblastic differentiation of human PLSCs.

Materials and Method

In this in vitro study, human PLSCs were cultured in mediums supplemented with Guidor Easy-Graft [βTCP+polylactide-co-glycolide (PLCG)+n-methyl-2-pyrrolidone (NMP)] [Sunstar Company, Swiss] or Sorbone [βTCP] [Meta Company, South Korea] as two alloplasts experimental groups, mesenchymal cells differentiated into osteoblasts without alloplast as positive control group, and mesenchymal cells without osteoblastic induction as negative control group. Osteoblastic differentiation was evaluated using Alizarine Red staining and spectrophotometry to assay calcium deposits and real-time polymerase chain reaction to examine expression of alkaline phosphatase (ALP) and osteopontin (OPN) antigens on day 21. Data were analyzed by using SPSS 22 software and one-way ANOVA and Bonferoni tests (p< 0.05).

Results

Spectrophotometry confirmed that calcium deposits were higher in Guidor Easy-Graft group compared to Sorbone group (p< 0.001) and higher in two experimental groups than controls (p< 0.05). According to real-time polymerase chain reaction, level of ALP expression was higher in Sorbone than Guidor and the levels of Guidor, positive control and negative control were equal; OPN levels of the positive control were more than the other groups. OPN levels of Sobone, Guidor and negative control were the same.

Conclusion

These findings indicated that Guidor Easy-Graft and Sorbone enhanced differentiation of human PLSCs to osteoblasts, and could be employed as appropriate bone-graft materials.

Biocompatibility of a HA/β-TCP/C Scaffold as a Pulp-Capping Agent for Vital Pulp Treatment: An In Vivo Study in Rat Molars

Bioceramic materials possess desirable biological properties, highlighting their non-reactivity and osteoconductivity. Their use has been extended in vital pulp treatment. The purpose of this study was to evaluate and compare the effects of beta-tricalcium phosphate (β-TCP), hydroxyapatite (HA), and collagen (C) scaffold with mineral trioxide aggregate (MTA) on the vital pulp of rat molars. Thirty-two molars of Sprague–Dawley rats underwent direct pulp capping with β-TCP/HA/C (n = 16) and MTA (n = 16). After 30 days, the following parameters were evaluated in the tested samples: the degree of pulp inflammation and pulp vitality, the presence of reparative dentin, the homogeneity of the odontoblastic layer, and the presence of pulp fibrosis. No statistically significant differences were observed between HA/β-TCP/C and MTA in terms of the degree of inflammation (p = 0.124). Significant differences were found in reparative dentin formation between the treatment groups (p = 0.0005). Dentin bridge formation was observed in the MTA-treated group. The local action of HA/β-TCP/C is similar to that of MTA when used as an agent for pulp vital treatment in terms of absence of inflammation and maintenance of pulp vitality, although there are significant differences between both materials regarding the formation of dentin bridges.

Can the Combination of Simvastatin and Melatonin Create a Synergistic Effect on Bone Regeneration?

PURPOSE

The present study evaluated the potential bone regeneration capacity of combining melatonin and simvastatin, with a goal of producing more osteogenic bone substitutes.

MATERIALS AND METHODS

A total of 48 male Wistar rats were randomly divided into 4 groups. The following were administered into critical-sized calvarial defects of the rats: Group I-human allograft; Group II-human allograft + 10 mg melatonin; Group III-human allograft + 0.1 mg simvastatin; and Group IV-human allograft + 10 mg melatonin + 0.1 mg simvastatin. Histopathologic, histomorphometric, and microcomputed tomographic evaluations were performed postprocedurally at 4 and 8 weeks. A P value < .05 was considered significant for all evaluations.

RESULTS

Groups II and III had significantly superior regeneration compared to Group I at weeks 4 and 8. Group III had significantly superior regeneration compared to Group II, particularly in week 4. Group IV had significantly superior regeneration compared to all groups at week 8.

CONCLUSIONS

The local administration of melatonin and simvastatin resulted in increased new bone mass and quality of bone microstructure than was seen in the control group. Simvastatin shortened the defect regeneration time more effectively than melatonin did. The combined use of melatonin and simvastatin provided a synergic effect on bone regeneration, particularly in the late phase of healing.

Photoencapsulated-mesenchymal stromal cells in biodegradable thiol-acrylate hydrogels enhance regeneration of craniofacial bone tissue defects

Aim: This study investigated biodegradable thiol-acrylate hydrogels as stem cell carriers to facilitate cranial bone regeneration. Materials & methods: Two formulations of thiol-acrylate hydrogels (5 and 15 wt% Poly[ethylene glycol]-diacrylate [PEGDA] hydrogels) were used as stem cell carriers. Bone marrow mesenchymal stromal cells and dental pulp mesenchymal stromal cells were photoencapsulated and cultured in basal or osteogenic medium 3 days before the surgery. Using New Zealand White Rabbits, four defects (5 mm diameter and 2 mm thickness) were created and hydrogel scaffolds were implanted in each rabbit cranium for 6 weeks. Results & Conclusion: AlamarBlue assay showed increasing metabolic activity levels in 5 wt% PEGDA hydrogels than 15 wt% PEGDA hydrogels. Photoencapsulated-mesenchymal stromal cells in 15 wt% PEGDA hydrogels demonstrated significantly increasing alkaline phosphatase activity levels on day 7 compared with days 1 and 3. Histological diagnosis showed 5 wt% PEGDA hydrogels resulted in lower averaged residual gel areas than 15 wt% PEGDA hydrogel specimens and control groups 6 weeks postimplantation.