Establishment and application of an in vitro model for apatite crystal mineralization / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To establish an in vitro model for the apatite crystal mineralization. To evaluate the influences of bovine serum albumin (BSA) and fluoride to the mineralization of apatite crystal.</p><p><b>METHODS</b>The model was constructed using cation selective membrane (CMV) and dialysis membrane. Double distilled water (DDW), BSA, 5, 20, 100 mg x L(-1) fluoride were added into the reaction space of the model. Reaction was carried out at 37 degrees C for 3 days under gentle stirring. The crystals were identified by scanning electron microscope (SEM) and X-ray diffraction (XRD).</p><p><b>RESULTS</b>The model was established successfully. When DDW and BSA were added respectively, the main component of the deposit was octacalcium phosphate (OCP), but the shape and size of the crystals differs from each other. When fluoride with different concentration were added, the main component of the crystal turned to rod-like and prism-like fluoroapatite (FAP) crystal. The size and crystallinity of the FAP increased with the increase of the fluoride concentration.</p><p><b>CONCLUSION</b>It is an effective way to evaluate the influence factors of the apatite crystal mineralization by using the in vitro model.</p>

Tissue engineering of dentin-pulp complex-like structures by human dental mesenchymal cells / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To establish three-dimensional culture model of human dental mesenchymal cells and bioengineer in vivo with ceramic bovine bone (CBB) and Collagraft as scaffolds.</p><p><b>METHODS</b>Human dental mesenchymal cells induced upon stimulation of bFGF and IGF-1 or TGF-beta(1) were implanted onto CBB and Collagraft containing the same kinds of growth factors respectively. Then cell/scaffold constructs were transplanted into nude mice to establish in vivo culture model of dental mesenchymal cells. Control groups were set up at the same time. After 4 weeks or 10 weeks, the implants were taken out for histological and immunohistochemical analysis.</p><p><b>RESULTS</b>Within 10-week implant tissues, typical dentin-pulp complex-like structures were generated in scaffolds containing growth factors. Human dentin sialoprotein (DSP) was expressed in the newly formed dentin. This phenomenon wasn't observed in control groups and 4-week implants.</p><p><b>CONCLUSIONS</b>Dentin-pulp complex-like structures could be bioengineered successfully with human dental mesenchymal cells and CBB or Collagrafts containing growth factors in nude mice.</p>

Immortalized human odontoblast-like cell line expressed dentin extracellular matrix in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To determine whether dentin matrix proteins were expressed by the human odontoblast-like cell line hTERT-hOd-1 in vitro.</p><p><b>METHODS</b>Collagen type I, bone sialoprotein (BSP), dentin matrix protein 1 (DMP1) and the marker for odontoblast, dentin sialophosphoprotein (DSPP) and dentin sialoprotein (DSP) were detected in these cells by immunohistochemistry, RT-PCR and in situ hybridization. During being cultured in mineralizing medium for 5 weeks, the secretion of OC and activity of ALP were measured once a week.</p><p><b>RESULTS</b>DSPP, DMP1, BSP and collagen type I were expressed in hTERT-hOd-1 either at mRNA or protein level. Under the induction of mineralizing medium, the cells showed higher activity of ALP and increased secretion of OC.</p><p><b>CONCLUSION</b>hTERT-hOd-1 expressed dentin extracellular matrix in vitro, which means the cell line has the potential of mineralization.</p>