ABSTRACT
Bioceramic tooth powders were prepared via heat treatment of extracted human teeth using sintering temperatures between 600°C and 1200°C, and their properties were investigated for potential tooth tissue engineering. The sintered human tooth powders were characterized using thermal analysis (thermogravimetric analysis (TG) and differential thermal analysis (DTA)), field emission scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, and Fourier transformed infrared (FTIR) spectroscopy. Additionally, the phase constitutions and chemical homogeneities of the composite samples were examined using a quantitative chemical analysis with inductively coupled plasma spectroscopy. The results revealed that the annealing process produced useful hydroxyapatite-based bioceramic biomaterials when annealed above 1000°C. The FTIR spectra and the TG/DTA thermograms of the tooth powders indicated the presence of organic compounds, which were completely removed after annealing at temperatures above 1000°C. The tooth powders annealed between 1000°C and 1200°C had good characteristics as bioceramic biomaterials. Furthermore, the biocompatibility of each tooth powder was evaluated using in vitro and in vivo techniques; our results indicate that the prepared human tooth powders have great potential for tooth tissue engineering applications.
Subject(s)
Calcium Phosphates/chemistry , Ceramics/chemistry , Tissue Engineering/methods , Tooth/physiology , Animals , Biocompatible Materials/chemistry , Bone Marrow Cells/cytology , Humans , Male , Materials Testing , Mice , Mice, Inbred BALB C , Microscopy, Electron, Scanning/methods , Powders/chemistry , Regeneration , Spectroscopy, Fourier Transform Infrared/methods , Stem Cells/cytology , Temperature , Thermogravimetry/methods , X-Ray Diffraction/methodsABSTRACT
BACKGROUND: LHX8 (LIM-homeobox gene 8) is known as an important regulating factor in tooth morphogenesis. Odontoma is a mixed odontogenic tumor where epithelium and mesenchyme differentiated together, resulting in anomalous tooth structures. In this study, gene and protein expressions of LHX8 were analyzed in human odontoma-derived mesenchymal cells (HODC) compared to adult dental mesenchymal stem cells (aDSC), as well as morphological and histological characteristics of odontoma were analyzed. METHODS: aDSCs were isolated from normal teeth, and HODCs were isolated from surgically removed odontoma mass. Morphological and histological evaluations were performed to compare between compound odontomas and normal premolars. RT-PCR and real-time PCR were performed to identify LHX8 mRNA expression in the HODCs and aDSCs. LHX8 protein expression levels were observed by immunoblotting and immunofluorescent staining. RESULTS: The compound odontoma was composed of multiple tooth-like structures, which contained disorganized but recognizable enamel matrix, dentin, pulp, and cementum. LHX8 mRNA and LHX8 protein expressions were all higher in HODCs compared to those in aDSCs examined by RT-PCR, immunoblot, and immunofluorescent staining. Especially, real-time PCR showed 2.77-fold higher LHX8 expression in HODCs than in normal periodontal ligament stem cells (PDLSCs), while alveolar bone marrow stem cells (ABMSCs) expressed 0.12-fold LHX8 than PDLSCs. CONCLUSIONS: Based on these observations, LHX8 might play an important role in odontoma formation. This is the first report regarding the comparison of LHX8 expression between HODC and normal aDSCs and its overexpression in human samples. The specific mechanism of LHX8 in odontoma morphogenesis awaits further study.
