Human dental pulp stem cell is a promising autologous seed cell for bone tissue engineering / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The seed cell is a core problem in bone tissue engineering research. Recent research indicates that human dental pulp stem cells (hDPSCs) can differentiate into osteoblasts in vitro, which suggests that they may become a new kind of seed cells for bone tissue engineering. The aim of this study was to evaluate the osteogenic differentiation of hDPSCs in vitro and bone-like tissue formation when transplanted with three-dimensional gelatin scaffolds in vivo, and hDPSCs may become appropriate seed cells for bone tissue engineering.</p><p><b>METHODS</b>We have utilized enzymatic digestion to obtain hDPSCs from dental pulp tissue extracted during orthodontic treatment. After culturing and expansion to three passages, the cells were seeded in 6-well plates or on three-dimensional gelatin scaffolds and cultured in osteogenic medium. After 14 days in culture, the three-dimensional gelatin scaffolds were implanted subcutaneously in nude mice for 4 weeks. In 6-well plate culture, osteogenesis was assessed by alkaline phosphatase staining, Von Kossa staining, and reverse transcription-polymerase chain reaction (RT-PCR) analysis of the osteogenesis-specific genes type I collagen (COL I), bone sialoprotein (BSP), osteocalcin (OCN), RUNX2, and osterix (OSX). In three-dimensional gelatin scaffold culture, X-rays, hematoxylin/eosin staining, and immunohistochemical staining were used to examine bone formation.</p><p><b>RESULTS</b>In vitro studies revealed that hDPSCs do possess osteogenic differentiation potential. In vivo studies revealed that hDPSCs seeded on gelatin scaffolds can form bone structures in heterotopic sites of nude mice.</p><p><b>CONCLUSIONS</b>These findings suggested that hDPSCs may be valuable as seed cells for bone tissue engineering. As a special stem cell source, hDPSCs may blaze a new path for bone tissue engineering.</p>

Clinical effect of the use of dental operating microscope and ultrasonic instruments in the management of blocked canals / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of using dental operating microscope and ultrasonic instruments in treating blocked canals.</p><p><b>METHODS</b>The etiology of canal blockage included calcification, broken instruments, posts, resinifying, etc. 236 blocked canals were treated with ultrasonic tips under dental operating microscope. The success rate was calculated.</p><p><b>RESULTS</b>178 blocked canals were successfully managed with a success rate of 75.4%. The success rate of each category of the blocked canals were: 71.7% for calcified canals, 81.1% for broken instruments, 100% for canals blocked by posts, 62.5% for canals blocked by resinifying therapy, and 84.1% for canals blocked by filling materials.</p><p><b>CONCLUSION</b>The use of dental operating microscope and ultrasonic instruments is proved to be an effective method in the management of blocked canals.</p>