Introduction: Stem cells from human exfoliated deciduous teeth (SHED) are highly proliferative, clonogenic cells capable of differentiating into osteoblasts and inducing bone formation. It is a potential alternative for stem cell bone regeneration therapy. However, stem cell therapy carries the risk of immune rejection mediated by inflammatory cytokines of the human defense system. Objective: This preliminary research studies the interaction between SHED and the immune system by determining the inflammatory cytokines profile and osteogenic potential of SHED. Methods: Human fetal osteoblasts (hFOb) cell line and isolated SHED were cultured and total RNA was extracted, followed by reverse transcription cDNA synthesis. Semi-quantitative reverse transcription PCR and Multiplex PCR were performed to detect the expression levels of OPG/RANKL and TNF-α, IL-1β, IL-6, IL-8 and TGF-β in both cell types. Results: Analysis showed that SHED expressed significantly lower amounts of IL-1β, IL-6, and IL-8 compared to hFOB. IL-1β is a potent bone-resorbing factor, while IL-6 and IL-8 induce osteoclastogenesis and osteolysis respectively. SHED did not express TNF-α which stimulates osteoclastic activity. SHED demonstrated high OPG/RANKL ratio, in contrast with that of marrow stem cells described in previous studies. Our findings suggest that SHED may have improved immunomodulatory profile in terms of promoting relatively lower inflammatory reaction during transplant and enhancing bone regeneration. Conclusion: SHED has a potential to be a good source of osteoblasts for bone regeneration therapy. Further studies on the immunomodulatory properties of SHED-derived osteoblasts are necessary to enable stem cell therapy in immunocompetent hosts.
Use of synthetic hydroxyapatite (HA) in biomedical applications is well warranted. It has shown to have an excellent biocompatibility in human tooth and bones. Additionally it has been documented to possess antibacterial potentials. The present study was conducted to assess the presence of any such potential in locally produced (HA) using Streptococcus mutans, a common pathogen in the oral cavity. The study was carried out using 50, 100, 150, 200, 300, 400 and 800 mg/ml concentration of HA. The antibacterial property of HA was assessed using Miles and Misra method. Our studies showed that bacterial growth inhibitions of S. mutans occurred from 50 mg/ml, and complete inhibition was perceived at concentrations at 200mg/ml of HA. The antibacterial property HA should be used to good advantage as a bioactive biomaterial in dental and maxillofacial applications.
Mutagenicity of CORAGRAF (natural coral) and REKAGRAF (hydroxyapatite) was tested in Ames test with and without an external metabolic activation system (S9). The test revealed no mutagenic activity of both locally produced osseous substitutes.
The aim of this study was to isolate stem cells from dental pulp of primary molars and incisors to be used as possible source for tissue engineering. Human primary molars and incisors were collected from subjects aged 4-7 year-old under standardized procedures. Within 24 hours, the tooth was cut at the cemento-enamel junction using hard tissue material cutter. The dental pulp tissue was extracted, digested and then cultured in Alpha Modified Eagles's Medium (α-MEM) supplemented with 20% FCS, 100 mM L-ascorbic acid 2-phosphate, 200 mM L-glutamine and 5000 units/ml Penicillin/Streptomycin. The cells were observed daily under the microscope until confluence. Children's tooth pulp- derived progenitor cells were found positive for stem cell markers CD105 and CD166, which are consistent with the finding for mesenchymal stem cells (MSCs) from bone marrow.
The human fibroblast MRC-5 cells incubated with PHB granules (TM) added at a final concentration of 4 mg/ml showed a time-course pattern of survival. The percentages of dead cells obtained were at the rate of 3.8% after 7 days, respectively. When the MRC-5 cells grown in different material, using the test concentration of 4 mg/ml PCM, they were found to show a similar time-course increasing pattern of death as that obtained with PHB. However, the death was noted in the cells incubated for 7 days, the death rates obtained was 40.54% respectively.
The aim of this study was to evaluate the in vitro cytotoxicity of biomaterials; Hydroxyapatite (HA), Natural coral (NC) and Polyhydroxybutarate (PHB). Three different materials used in this study; HA (Ca10(PO4)6(OH)2), NC (CaCO3) and PHB (Polymer) were locally produced by the groups of researcher from Universiti Sains Malaysia. The materials were separately extracted in the complete culture medium (100mg/ml) for 72h and introduced to the osteoblast cells CRL-1543. The viability of osteoblast CRL-1543 cultivated with these extraction materials after 72h incubation period was compared to negative control with neutral red assay by using spectrophotometer at 540nm. The results showed the non-cytotoxicity of the materials. After 72h of incubation period, HA showed 123% viable cells, NC was 99.43% and PHB was 176.75%. In this study, cytotoxicity test dealt mainly with the substances that leached out from the biomaterial. The results obtained showed that the materials were not toxic and also promoted cells growth in the sense of biofunctionality.