Expression and biological roles of heat shock protein 25 in rat dental follicle cells / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To examine the expression of heat shock protein 25 (HSP-25) in dental rat follicles in vivo and in vitro in order to investigate the possible effect of HSP-25 on cell proliferation and alkaline phosphatase (ALP) activity.</p><p><b>METHODS</b>The expression of HSP-25 in mandibles of postnatal rats from day 1, 3, 5, 7, 9, 11 was examined by immunohistochemistry in vitro, the expression of HSP-25 in the dental follicle cells was detected by the indirect immunofluorescence method. Methyl thiazolyl tetrazolium (MTT) assay, flowcytometry and ALP assay were used to detect the effect of HSP-25 on rat dental follicles.</p><p><b>RESULTS</b>HSP-25 expression was absent or weak in rat dental follicle cells at early postnatal stage and present from day 5 till day 11. HSP-25 was detected in the cytoplasm of cultured dental follicle cells. MTT results showed no effect could be detected on dental follicle cell proliferation after stimulation of different concentrations of HSP-25 on day 1, 2, 3. Flowcytometry results also exhibited no difference in cell cycles after stimulation of HSP-25 at 0 microg/L and 100 microg/L. HSP-25 at a concentration of 50 microg/L and 100 microg/L could up-regulate the ALP activity on day 9.</p><p><b>CONCLUSIONS</b>Expression of HSP-25 increases chronologically in the rat dental follicle cells. HSP-25 locates in the cytoplasm of cultured rat dental follicle cells. HSP-25 has no effect on the proliferation of dental follicle cells, however it can up-regulate the ALP activity.</p>

HSP25 affects the proliferation and differentiation of rat dental follicle cells / 国际口腔科学杂志·英文版

<p><b>AIM</b>To detect the expression of HSP25 in rat dental follicles both in vivo and vitro, and explore the underlying mechanism of HSP25 on the proliferation and differentiation of rat dental follicle cells (DFCs).</p><p><b>METHODOLOGY</b>Immunohistochemistry was performed to detect the expression of HSP25 in mandibles of postnatal rats on days 1, 3, 5, 7, 9 and 11 in vivo. In vitro, the expression of HSP25 in DFCs was detected by an indirect immunofluorescence assay. Thiazolyl blue tetrazolium bromide (MTT) assay, flow cytometry and alkaline phosphatase (ALP) assay were used to identify the time-course effect mediated by different concentrations of recombinant murine HSP25 of 0, 1, 10, 50 and 100 ng/mL on rat DFCs.</p><p><b>RESULTS</b>Expression of HSP25 was not detected in dental follicles of the rats until day 5 after birth, but became up-regulated in a time-dependent manner till day 11. HSP25 was detected in the cytoplasm of cultured rat DFCs. No significant difference could be observed in the proliferation of DFCs after stimulation with different concentrations of HSP25 on days 1, 2 and 3 (P > 0.05). HSP25 at concentrations of 50 ng/mL and 100 ng/mL up-regulated the ALP activity of DFCs on day 9 (P < 0.05).</p><p><b>CONCLUSION</b>HSP25-immunoreactivity increased chronologically during the development of dental follicles. The protein had no significant effect on cell proliferation but may play a role in cementoblast/osteoblast differentiation of DFCs.</p>

Clinical evaluation of periapical endodontic surgery for endodontic failure / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the clinical outcome of periapical endodontic surgery for teeth that can't be treated by nonsurgical endodontic methods.</p><p><b>METHODS</b>Sixty-two affected teeth were chosen for surgical endodontic treatment, of which 31 teeth underwent periapical curettage and the others were treated by root-end resection, retrograde preparation and filling. A radiography was taken immediately after surgery and was compared with those taken at 12 and 24 months. The results of two groups were analyzed using the chi2 test.</p><p><b>RESULTS</b>The success rate for retrograde filling was higher (85% after 12 months, 88% after 24 months) compared with that of periapical curettage (52% after 12 months, 45% after 24 months). The difference in success rate between the two groups was statistically significant.</p><p><b>CONCLUSIONS</b>Ultrasonic root-end preparation and retrograde filling is a good choice of treatment when the teeth can't be treated appropriately by nonsurgical treatment.</p>

Evaluation of sealing ability of three kinds endodontic materials as root canal sealers / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To compare the apical microleakage of Vitapex (calcium hydroxide based paste) with that of AH-plus and zinc oxide eugenol sealer when used with laterally condensed gutta percha obturation technique.</p><p><b>METHODS</b>One hundred single rooted human anterior teeth were instrumented and randomly divided into three experimental groups (A, B, C) of 30 teeth each and two control groups (D, E) of 5 teeth each. Group A was filled with laterally condensed gutta-percha using Vitapex as sealer. Group B was filled with laterally condensed gutta-percha using AH-plus as sealer. Group C was filled with laterally condensed gutta-percha using zinc oxide eugenol as sealer. Group D was the positive control. Group E was the negative control, which were coated with nail polish to entire root surface. Teeth were then suspended in 2% methylene blue. After this, teeth were demineralized dehydrated and cleared. Linear dye penetration was determined under stereomicroscope with calibrated eye piece.</p><p><b>RESULTS</b>The mean dye penetration for group A, B, C were respectively (0.57 +/- 0.56) mm, (0.79 +/- 0.96) mm and (1.07 +/- 1.12) mm. Group D demonstrated maximum dye penetration. Group E showed no dye penetration. There was no statistically significant difference between group B and group C (P > 0.05). However, there was statistically significant difference between group A and group B, C (P < 0.01).</p><p><b>CONCLUSION</b>This study showed that Vitapex used as endodontic sealer material are better than AH-plus sealer and zinc oxide eugenol sealer.</p>

Clinical management of open apices teeth with mineral trioxide aggregate (MTA) as apical barrier in adults / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the clinical effect of treatment of open apices teeth with mineral trioxide aggregate (MTA) compared with apexification using Vitapex in the adult.</p><p><b>METHODS</b>The root canals of 41 anterior teeth and premolars with single canal and open apices in adults were cleaned and shaped, and then disinfected with calcium hydroxide. The apical root canals of 21 teeth in experimental group were filled with MTA to create a 3-5 mm apical barrier. The remainder of the canals was filled with AH plus and Obtura II gutta-percha. The canals of 20 teeth in control were treated with Vitapex. The root canals were then filled with Obtura II gutta-percha when the apical barrier could be detected. The visit times, period and result of the treatment were recorded for all cases.</p><p><b>RESULTS</b>Good result was achieved in the most cases in the experimental group. The postoperative X-ray films showed that the canals of 15 teeth were obturated well. 6 teeth showed over-filling by 0.5-2 mm. The recalled patients declared their teeth to be asymptomatic except one. The recall radiographs indicated that the apical radiolucent areas of the teeth with pre-existing apical lesion decreased apparently or disappeared completely, except one tooth with large apical radiolucency. No new radiolucency was found around the roots. In the control group, the apexification of 11 teeth succeeded, and 9 failed. The average visit times was 3.5 in experimental group and 6.0 in control. The average period of the whole endodontic treatment was 11.8 days in experimental group and 306.8 in control.</p><p><b>CONCLUSION</b>MTA is more effective and quicker than apexification in treatment of teeth with open apices in adults.</p>

Clinical evaluation of two types of NiTi rotary instruments in preparation of root canals / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate clinical effects of two types of nickel-titanium rotary instruments in preparation of molars' root canals.</p><p><b>METHODS</b>100 molars with pupal and periapical involvement were instrumented by Protaper and Hero642 files with crown-down technique. All teeth were obturated with lateral condensation method. Straightening of canal curvature was determined. The efficiency of preparation and obturation was analyzed with radiograph before, during and after operation.</p><p><b>RESULTS</b>The operating time of each NiTi group was short. The two NiTi rotary instruments could achieve continuously tapered root canal shape. The curvature of the canal reduced by -4.02 degrees +/- 2.80 degrees with Protaper and 1.72 degrees with Hero642 (P < 0.001). Five pieces of Protaper with broken, whereas no Hero642 was broken (P < 0.05).</p><p><b>CONCLUSIONS</b>Protaper, Hero642 files showed good shaping ability and improved predictability in root canal obturation. Protaper can lessen canal curvature more significantly. Hero642 files are easy to operate and not easy to separate.</p>

Establishment of cultivating technology of dental follicle cells of rat and their identifying / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To establish a method for culturing dental follicle cells of rat and observe the growth characteristics of the cultured cells in vitro.</p><p><b>METHODS</b>Dental follicle and associated enamel organs were dissected from the first and second mandibular molars of 6-7-day-old rats, and then cultured in vitro. Purified dental follicle cells derived from the third or the fourth passage cells were utilized in the following experiments. The shape and ultrastructure of dental follicle cells were observed by light-microscopy and transmission electron microscopy. Immunocytochemistry was used to detect the expression of vimentin, type I collagen and fibronectin.</p><p><b>RESULTS</b>The cultured cells were fibroblastic in shape, elongate with processes, and transmission electron microscopy revealed that they contained electron-dense granules, an abundant rough endoplasmic reticulum, but did not form desmosomes. Vimentin, type I collagen and fibronectin were present in dental follicle cell.</p><p><b>CONCLUSION</b>The dental follicle cells of rat could be successfully cultured in vitro and the cultured cells had the same characteristics of dental follicle cells of normal rat.</p>

Colony-stimulating factor-1 receptor in rat dental follicle cells / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study localization and expression of CSF-1 receptor protein, in order to discover the CSF-1 and IL-1alpha effects on CSF-1 receptor mRNA levels and to determine if the autocrine effect is inhibited through the CSF-1 receptor.</p><p><b>METHODS</b>Immunolocalization of CSF-1 receptor in the cultured dental follicle cells and in mandibles of the post-natal rats from day 1 to 11 were performed. The effects of different concentrations of CSF-1, IL-1alpha on CSF-1 receptor gene expression were detected by means of RT-PCR.</p><p><b>RESULTS</b>Cultured dental follicle cells were immunostained for the CSF-1 receptor. In vivo, immunostaining showed that the CSF-1 receptor was present in the dental follicle of the first mandibular molar at early post-natally and was either absent or greatly reduced by day 11 post-natally. High concentrations of cvCSF-1 reduced the gene expression of the CSF-1 receptor. IL-1alpha had no effects on CSF-1 receptor mRNA levels.</p><p><b>CONCLUSIONS</b>The expression of CSF-1 receptor reaches a peak early post-natally in the dental follicle of the first mandibular molar of the rat and then subsequently declines. High concentrations of CSF-1 inhibits the expression of CSF-1 receptor, IL-1alpha has no effect on the expression of CSF-1 receptor mRNA.</p>