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Table of Content
20 October 2006, Volume 24 Issue 05
  • Differential Regulation of P2X3 Protein Expression in the Rat Trigeminal Ganglion after Experimental Tooth Movement
    CAO Yang1, LAI Wen-li2, CHEN Yang-xi2
    West China Journal of Stomatology. 2006, 24(05):  389-392. 
    Abstract ( 861 )   HTML ( 2 )   PDF(pc) (196KB) ( 498 )   Save
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    Objective  To investigate the regulation of P2X3 protein expression in the trigeminal ganglion sensory neurons after the nociceptive stimulation by orthodontic tooth movement force. Methods  Male Sprague-Dawley rats weighing 200-250 g were used. The mimic tooth movement appliance was used in experimental group rats. The animals were sacrificed after 4 h, 1 d, 2 d, 3 d, 5 d, 7 d and 14 d. The semi-quality of P2X3 protein was measured by Western blot. The expression place and strength of P2X3 was detected by in situ hybridization with an oligonucleotide probe in the same time. Results  A major specific protein of 4.5×104 was found by Western blot in trigeminal ganglion of rats. The expression strength of P2X3 receptor increased after given force to the teeth of rats from 1 day of experiment, 3 day group rats showed peak change. 14 day group had returned to control values. The level change of P2X3 mRNA expression showed the same result. Conclusion  The results suggest that the P2X3 receptor expression is transiently upregulated and anterogradely transported in trigeminal primary sensory neurons after orthodontic tooth movement and that P2X3 receptor may play role in the pathomechanism of nociceptive in primary sensory neurons during orthodontic clinic treatment.

    Biomechanical Study of Rigid Internal Fixation for Mandibular Angle Fracture
    WANG Hang1, CHEN Meng-shi2, TANG Wei3, TIAN Wei-dong3
    West China Journal of Stomatology. 2006, 24(05):  393-396. 
    Abstract ( 1083 )   HTML ( 3 )   PDF(pc) (161KB) ( 484 )   Save
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    Objective  To develop a functional biomechanical mandibular model, and to observe the stress distribution of angle-fractured mandible under different rigid internal fixation(RIF) methods. Methods  A biomechanical model of mandible was built which include the simulative temporal-mandibular joint(TMJ) and was under mechanical loads of masseter, temporalis, medial pterygoid and lateral pterygoid. The different stress pattern was measured by strain gauges. Under the standard mandibular angle fracture, bilateral molar biting and four pairs of muscles loading, the strains were compared to evaluate the stability of one-or two-miniplate fixation. Results  The fixation of miniplate in the lateral oblique line can recover the main stress on the non-fracture side, but it was broken in the fracture side. The tension increased in the lower border of mandibular angle. Conclusion  Through the biomechanical study based on the functional mandibular model, only one miniplate fixation in lateral oblique line for mandible angle fracture was insufficient buttressing of the segments, while the additional miniplate in the lower margin can recover the stress pattern and provide more stability.

    Time Varied Stress Effects on the Shape-alteration of Myoblast in Rats
    SONG Jin-lin1, FAN Yu-bo2, ZHAO Zhi-he2, DENG Feng1, ZHENG Lei-lei2
    West China Journal of Stomatology. 2006, 24(05):  397-399. 
    Abstract ( 855 )   HTML ( 1 )   PDF(pc) (224KB) ( 288 )   Save
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    Objective  To investigate the effects of time varied stress on the shape-alteration of myoblast in rats and to provide a theoretic base to determine the mechanics of myoblast in orthodontic therapy. Methods  Based on the pulsatile mechanical system our group founded, this study loaded different strain(2.5 kPa、5.0 kPa and 10.0 kPa) to the myoblast of lateral pterygoid muscle. The alterations in shape under time varied stress of 6 h and 12 h were assessed by phase-contrast microscopy, scanning electron microscope. Results  The orientation of myoblast seemed no obvious orderliness before loading. But after loading the lower time varied strain(2.5 kPa, 5.0 kPa), they were changed their orientation to paralel with the direction of strain along with the membrane. Meanwhile, there had one trend to set the shape of myoblast more upright along with the membrane after loading the higher time varied stress(10.0 kPa). Conclusion  It was proved that the different time varied stress in vitro expressed the different influence on the remolding of myoblast.

    Cloning of the RgpAcd Gene of Porphyromonas gingivalis and Its Expression in E. coli
    XU Jing1, LI Ang2, GOU Jian-zhong3, XU Yuan-chao2, RAO Guo-zhou2, LIU Zheng3, XIE Hong-guo3
    West China Journal of Stomatology. 2006, 24(05):  400-403. 
    Abstract ( 1047 )   HTML ( 2 )   PDF(pc) (279KB) ( 427 )   Save
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    Objective  To clone the catalytic domain gene sequence of RgpAcd of Porphyromonas gingivalis(P.gingivalis) and to induce its fusion expression in E. coli. Methods  The desired DNA fragment RgpAcd was obtained by PCR and was separately sequenced and identified by inserting into inter-vector pMD18-T vector. The correctly fragment was linked with and cloned into a prokaryotic expression vector pET-15b. The recombinant expression plasmid which had been confirmed by enzymes digestion was transformed to E. coli competent cells BL21(DE3) and expression of fusion protein was induced by IPTG. Results  A 1 476 bp specific fragment was obtained and DNA sequencing showed that the fragment was consistent with those of the published. After induction with IPTG, a fusion protein of 5×104 was visualized on SDS-PAGE gel. Conclusion  The protein of RgpAcd will be obtained for further study and its protein was correctly expressed in E. coli BL21 cells.

    Influence on Mechanical Properties and Microstructure of Nano-zirconia Toughened Alumina Ceramics with Nano-zirconia Content
    WANG Guang-kui1, KANG Hong1, BAO Guang-jie1, LV Jin-jun2, GAO Fei2
    West China Journal of Stomatology. 2006, 24(05):  404-406. 
    Abstract ( 963 )   HTML ( 2 )   PDF(pc) (349KB) ( 548 )   Save
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    Objective  To investigate the mechanical properties and microstructure of nano-zirconia toughened alumina ceramics with variety of nano-zirconia content  in centrifugal infiltrate casting processing of dental all-ceramic. Methods  Composite powder with different ethanol-water ratio, obtained serosity from ball milling and centrifugal infiltrate cast processing of green, then sintered at 1 450 ℃ for 8 h. The physical and mechanical properties of the sintered sample after milling and polishing were tested. Microstructures of the surface and fracture of the sintered sample were investigated by SEM. Results  The experimental results showed that there had statistical significience (P<0.01) on static three-point flexure strength and Vickers Hardness in three kinds of different nano-zirconia content sintered sample. Fracture toughness of 20% group was different from other two groups, while 10% group had not difference from 30% group(P<0.05). The mechanical properties of this ceramic with 20% nano-zirconia was the best of the three, the static three-point flexure strength was(433±19) MPa and fracture toughness was(7.50±0.56) MPa·m1/2. The intra/inter structure, fracture of intragranular and intergranular on the surface and fracture of sintered sample in microstrucre was also found. Conclusion  Intra/inter structure has strengthen toughness in ceramics. It has better toughness with 20% nano-zirconia, is suitable dental all-ceramic restoratives.

    Effect of K2O Addition on the Crystallization Property of Dental Glass-ceramics
    LIU Xiao-qiu1, SONG Wen-zhi2, SUN Hong-chen1, YANG Hai-bin3, ZOU Guang-tian3, WANG Jing-yun1, YE Chang-li4
    West China Journal of Stomatology. 2006, 24(05):  407-409. 
    Abstract ( 894 )   HTML ( 1 )   PDF(pc) (270KB) ( 493 )   Save
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    Objective  To evaluate the effect of K2O addition on the crystallization property of dental glass-ceram-ics in the Li2O-SiO2-Al2O3-P2O5-ZnO system.  Methods  Different content of K2O was added into Li2O-SiO2-Al2O3-P2O5-ZnO glass system. The heat-treated system of the glass-ceramics was determined by differential thermal analyses(DTA), then the crystallization components and the microstructure of the glass-ceramics with different content of K2O were investigated from X-ray diffraction(XRD) analyses and scanning electron microscopy(SEM). Results  Addition of K2O helped to reduce the viscosity of the glass system and improved crystallization. More lithium disilicate crystals appeared after heated-treatment of the glass system which contained 5.3wt% addition of K2O, and the homogeneously lath-shaped crystals were 4 μm in length.  Conclusion  Certain content of K2O can improve the crystallization property of dental glass-ceramics in the Li2O-SiO2-Al2O3-P2O5-ZnO system.

    Research on Investing Methods and Mold Cooling Methods of the Self-made Investment for Pure Titanium Castings
    ZHAO Juan1, HUANG Xu2, ZHAO Yun-feng3, XIAO Mao-chun3, LI Yong3
    West China Journal of Stomatology. 2006, 24(05):  410-414. 
    Abstract ( 879 )   HTML ( 1 )   PDF(pc) (1898KB) ( 509 )   Save
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    Objective  To observe the influence of different investing methods and mold cooling methods on pure titanium castings invested in the self-made investment, and to provide theoretic base for the development for the investment. Methods  The influence of investing methods(one-step investing method and two-step investing method) on castability and crown fit of titanium castings were investigated, and the influence of cooling methods on reaction layers, mechanical properties and crown fit of titanium castings were investigated. Results  Both the investing methods exhibited good castability, but only the titanium full crowns by one-step investing method showed clinically acceptable fit. Although the quenching group showed thinner reaction layer(100 μm), lower strength and similar elongation rate, the titanium castings by bench cooling showed clinically acceptable full crown fit with 115 μm thick reaction layer as cast. Conclusion  The one-step investing method and the bench cooling are recommended for the self-made investment.

    Effects of Different Beverages on Plaque pH of Different Caries-sensitive Children
    LIU Yuan1, ZOU Jing2, SHANG Ran1
    West China Journal of Stomatology. 2006, 24(05):  415-418. 
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    Objective  To compare the impacts of different beverages on plaque pH of caries-sensitive and caries-free children and to evaluate the applicability of in situ pH measurements in human dental plaque using Beetrode microelectrode. Methods  The subjective population consisted of 20 children(aged 3-5 years). Ten of them were caries-free(dmft=0); the other were caries-active(dmft>4). The dental plaque pH were measured in situ with a pH microelectrode within 1 h after drinking three different beverages respectively. Then the resting pH value(pHrest), minimum pH value(pHmin), the range of the pH(△pH) was analyzed by ANOVA. Results  There was a significant difference in pHrest between caries-free and caries-sensitive children. All the pH responses in the plaque following drinking three different beverages showed a classic Stephan-type response. The differences of the pHmin, △pH in sound sites were no statistic significance(P>0.05) after drinking beverages in caries-free children. However the changes in the caries-sensitive group were more pronounced than the non-caries group. There were significant differences on the pHmin, △pH among different beverages(P<0.05). Conclusion  The cariogenicity of plaque in caries-active children was stronger than that of the caries-free group. Different beverages have different potential cariogenicity.

    Stereology Investigation of Muscle Spindles in Human Masseter and Temporalis Muscle
    ZHANG Yue-rong1, LIU Jing2, HUANG Yue3
    West China Journal of Stomatology. 2006, 24(05):  419-422. 
    Abstract ( 1052 )   HTML ( 1 )   PDF(pc) (242KB) ( 548 )   Save
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    Objective  To find out the characteristic topographic distribution of the muscle spindles in human masseter and temporal muscle, and to clarify the neurobiology roles of masticatory muscles during chew and adjusting mandibular position. Methods  The muscle spindles of masseter and temporal muscle on both sides of 5 human corpses fixed in formalin for more than 1 year were observed and quantitatively analyzed by picture analysis equipment. Results  The muscle spindles were maldistributed and spindles were commonly clustered in some individual portions, and the muscle spindle figures were diversiform, which were predominantly composed of the spindle simple and spindle complexes. the masseter spindles of the deep portion were obviously more than that of the superficial. Spindles of temporal muscle were concentrated in the anterior approach to the coracoid. Conclusion  The distribution of muscle spindles in the masseter and temporal muscle is heterogeneous, spindle density in the deep portion of masseter and the anterior of temporolismuscle is greater than others. The deep of masseter and the anterior of temporal muscle play an important part in maintaining mandibular position and balance.

    Primary Study of the Method for Repair of Severe Unilateral Complete Cleft Lip
    LIU Yun-sheng1, YANG Chun-hui2, MU Zong-zhi1, WANG Ke-tao1, WANG Bing1
    West China Journal of Stomatology. 2006, 24(05):  423-425. 
    Abstract ( 865 )   HTML ( 1 )   PDF(pc) (194KB) ( 411 )   Save
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     Objective  To evaluate the probability of repairing the severe cleft lip and nose in one time. Methods  35 patients were included. A revised method was presented based on the popular methods used. Results  Among 35 patients, the length of lip in two sides was equal in 33 patients, and the appearance of the nose shape was satisfactory in 31 patients evaluated by third expert group. Conclusion  The method presented in this paper could repair the abnormalities of the lip and nose effectively in severe cleft lip patients in one time and was adapted in the patients who could not be treated with serial methods because of a bad economic state.

    Influence of Timing Preparation on Coronal Microleakage of Cemented Cast Posts and Cores
    ZHOU Zheng, SHI Bin
    West China Journal of Stomatology. 2006, 24(05):  426-428. 
    Abstract ( 1096 )   HTML ( 4 )   PDF(pc) (237KB) ( 473 )   Save
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    Objective  To investigate the effect of coronal microleakage of cemented cast posts and cores after different interval time preparation. Methods  Cast posts and
    cores were fabricated for 60 of 66 extracted single-root mandibular premolars which randomly divided into 6 groups and cemented with zinc phosphate cement. The other 6 specimens acted as negative control group and positive control group. After 2, 10, 30 minutes interval time, preparation would do for preparation groups and three control groups without preparation. After dying and making transparent, the assessment of the coronal microleakage was done. Results  The results showed significant differences between each prepared group and unprepared group. No differences were defected in 3 unprepared groups. But significant differences were recorded between after 2, 10 minutes preparation groups and 30 minutes group. Conclusion  High-speed preparation had a significant negative effect on the coronal microleakage of posts. The interval time of preparation after cemented cast posts and cores was at least between 10 and 30 minutes.
    Comparison of Penetration and Obturation Density Using Nickel-titanium and Stainless-steel Spreader in Curved Canals
    XIA Zhi-min1, PENG Bin2, BIAN Zhuan2, FAN Ming-wen2
    West China Journal of Stomatology. 2006, 24(05):  429-431. 
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    Objective  To compare the initial penetration depth of nickel-titanium(NiTi) and stainless-steel(SS)spreader during lateral compaction and the quality of the seal in curved canals. Methods  Forty extracted mandibular premolars with a single curved canal were divided into two groups: no more than 20° and more than 20° based on degree of curvature. All canals were instrumented using a rotary instrumentation technique. NiTi and SS spreaders were used to obturate the canals containing a master cone while the penetration depths were measured. Horizontal sections were cut in 2 and 4 mm from the apex and photographed under stereomicroscope. The percentage of gutta-percha-filled are(PGP) of cross-sections was measured using an image analysis program. Results  In canals of more than 20°, the penetration depths and PGP of 2 mm from the apex of NiTi spreaders were higher than SS spreader. In canals of no more than 20°, there were no significant difference between them(P>0.05). At 4 mm from the apex, there was no significant difference between two groups. Conclusion  NiTi spreaders has a higher penetrated depth and obturation density than SS spreaders in severed curved canals.
    Clinical Study of Autotransplanting of Impacted Anterior Tooth and Premolar
    HUANG Jian-sheng, ZHOU Lei, XU Shu-lan, WU Ying, SONG Guang-bao
    West China Journal of Stomatology. 2006, 24(05):  432-434. 
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    Objective  To evaluate the effect of autotransplantation of impacted anterior tooth and premolar. Methods  Nineteen teeth of 19 patients were made
    autotransplantation. Fifteen impacted anterior teeth were transplanted to their normal positions. Four premolars were transplanted into missing anterior spaces. Four weeks after surgical procedure, root canal therapy was underwent. Clinical and radiographic examintation of 19 transplanted teeth were carried out after 18-months to 5-years. Results  Nineteen teeth were stable with no sign of inflammatory resorption or periapical lesion. Conclusion  Autotransplantation may be a better treatment method to impacted tooth and missing anterior when they can′t be treated by orthodontic method.
    Effect of Periodontitis on Circulating C-reactive Protein in Type 2 Diabetes Patients
    GU Yu-xin1, LI Qing-xing1, YOU Yan-ling1, LIU Guang-shun1, HAN Xu2
    West China Journal of Stomatology. 2006, 24(05):  435-437. 
    Abstract ( 1119 )   HTML ( 3 )   PDF(pc) (32KB) ( 532 )   Save
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    Objective  To investigate the effect of periodontal infection on circulating C-reactive protein(CRP) in type 2 diabetes patients. Methods  32 diabetes patients
    with advanced periodontitis participated in this study. They were compared to a group of 32 diabetes patients without periodontal disease, who were mathed with regard to age(±3 years), gender and body mass index(±1 kg/m2). The concentration of CRP on circulation was measured by ELISA.
    Results  Significant difference was found in the level of CRP and the percentage of subjects with elevated CRP levels≥3 mg/L on circulation between the two groups (P<0.05). Conclusion  Periodontal infection results in higher circulating CRP in type 2 diabetes patients. This elevated inflammatory factor may exacerbate insulin resistance and increase the risk for great vessels complications of  diabetes mellitus.
    Evaluation of Acid Diffusion and Fluoride Selective Electrode to Measure the Total Fluoride in Toothpastes
    WANG Xiao-ling, CHENG Chuo-yue, GE Yao, WANG Qin
    West China Journal of Stomatology. 2006, 24(05):  438-440. 
    Abstract ( 1099 )   HTML ( 1 )   PDF(pc) (30KB) ( 517 )   Save
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    Objective  To evaluate the reliability of a method of measuring the total fluoride in fluoride-containing toothpastes with acid diffusion and fluoride selective
    electrode. Methods  Four brands of commercially available non-fluoride toothpastes and fluoride-containing toothpastes were sampled. Fluoride was extracted from the toothpastes in 2 mol/L HClO4 at room temperature overnight and then subjected to the measurement with fluoride electrode. Results  Fluoride recovery of the non-fluoride toothpastes containing calcium as abrasive by this method was 99.5%-100.5%,more than 94% of total fluoride was measured from the marketed fluoride toothpastes, and the variation coefficient of this method was less than 1.54%. While the abrasive was silicon, the fluoride recovery of the non-fluoride toothpastes was 83.4%, and 89.7% of total fluoride was measured from the marketed fluoride-containing toothpastes. Conclusion  The amount of total
    fluoride in the calcium containing toothpaste can be detected simply and accurately measured by acid diffusion and fluoride selective electrode. 
    Influence of Adhesion on the Color of Glass Infiltrated Alumina Ceramic Restorations
    JIANG Li, YANG Liu, XU Qiang, GUAN Hong-yu, WAN Qian-bing
    West China Journal of Stomatology. 2006, 24(05):  441-443. 
    Abstract ( 1114 )   HTML ( 1 )   PDF(pc) (31KB) ( 444 )   Save
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    Objective  To investigate the effects of luting agent on the final color of glass infiltrated alumina ce-ramic restorations. Methods  12 plate-shaped specimens
    with 12.5 mm in diameter and 0.5 mm thickness were fabri-cated from GI-II(color IG2). Vitadur alpha veneering porcelain(color A2) with 1.0 mm thickness was fired  to GI-Ⅱ glass/alumina composite. 12 plate-shaped background specimens simulating the metal alloy post-and-core 12.5 mm in diameter and 2 mm thickness were also made  from Ni-Cr alloy. All-ceramic specimens were luted to the metal alloy by Zinc Phosphate cement, glass ionomer cement and composite resin. The color shifts of the specimens were measured by colorimeter. Results  Luting agents had effect on the final color of restorations. The influence of composite resin was least, followed by  glass ionomer cement and Zinc Phosphate cement. The color difference between with and without Zinc Phosphate cement could be identified by the eye. Conclusion  To  reduce the effect of luting agents, composite resin is recommended to all-ceramic restorations′ adhesion.
    Morphological Study and Ca/P Ratio Analysis of Er, Cr:YSGG Laser Irradiation on Periodontal Diseased Root Surfaces
    SUN Shu-ping, PAN Ya-ping, ZHANG Dong-mei, ZOU Bo
    West China Journal of Stomatology. 2006, 24(05):  444-446. 
    Abstract ( 1045 )   HTML ( 1 )   PDF(pc) (609KB) ( 560 )   Save
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    Objective  To observe the morphological transformation and Ca/P changes of the periodontally disease root surfaces irradiated by Er, Gr:YSGG Laser. Methods 
    18 periodontally diseased teeth and 6 wisdom teeth were collected in vitro. After 18 periodontally diseased teeth were planed, 12 teeth were randomly selected as the  laser treatment group, the others as the acid treatment group. The 6 wisdom teeth were selected as the healthy control.Then the evaluation for root surfaces
    morphological transformation was conducted by SEM. An energy spectrum analyzer was used to analyze the Ca/P ratio of root surfaces. Results  The root surfaces were clean and even in the laser treatment group. Smear layer could also be effectively eliminated in the laser treatment group and the acid treatment group, but the SEM results were different. Atom content analysis showed that the Ca/P ratio of the laser treatment group and the acid treatment group had no distinct difference. Conclusion  It is effective to remove smear layers and infected cementum of surface layers with Er, Cr:YSGG irradiating on the planed periodontal root surfaces
    Effect of Hyperthermia on Multidrug Resistance of Tongue Squamous Cell Carcinoma Cell Line(Tca8113)and Its Multidrug Resistance Cell Line Tca8113/CBDEA
    LENG Wei-dong1, WANG Da-zhang2, FENG Ge2, HE Jia2
    West China Journal of Stomatology. 2006, 24(05):  447-450. 
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     Objective  To study the effect of hyperthermia on expressions of multidrug resistance(MDR)genes intongue squamous cell carcinoma cell line Tca8113 and its MDR cell line Tca8113/CBDEA and intracellular ADM concentration. Methods  Cell lines were hyperthermia-treated(42 ℃ for 0.5 h), 4 h and 24 h later real-time quanti-tative reverse transcriptase-polymerase chain reaction(RT-PCR) detected expressions of MDR relative genes(MDR1, MRP1, GST-π)and HTS 7000 Plus Bio Assay Reader measured intracellular ADM concentration. Results  Expres-sions of MDR1, MRP1, GST-π genes in Tca8113/CBDEA significantly descended at 4 h and 24 h post-hyperthermia(P<0.01). Expressions of MDR1, MRP1 genes in Tca8113 significantly descended at 4 h and 24 h post-hyperthermia (P<0.05), but there was not statistical difference between 4 h and 24 h post-hyperthermia. GST-π expression had not statistical descent at 4 h, but there was significantly descend at 24 h post-hyperthermia(P<0.01). Drug tolerance decreased and hyperthermia increased intracellular drug concentration in Tca8113/CBDEA and Tca8113(P<0.01).Conclusion  Hyperthermia enhance chemotherapy effect and reverse MDR genes expression in tongue squamous cell carcinoma cell line. It is suggested that hyperthermia could be used as a method to overcome MDR, which is worth more investigation.
    Relationship between Nuclear Factor Kappa B Signal Transduction Way and the Sensitivity of Tongue Carcinoma Cell to Pingyangmycin Chemotherapy
    WU Jun-lou1, LIANG Xin-hua2, MAO Zu-yi2, XIAO Gui-zhou3
    West China Journal of Stomatology. 2006, 24(05):  451-454. 
    Abstract ( 984 )   HTML ( 1 )   PDF(pc) (747KB) ( 573 )   Save
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     Objective  To examine the relationship between NF-κB signal transduction way and the sensitivity of Tca8113 carcinoma cell to Pingyangmycin chemotherapy.
    Methods  2 mg/L antisense p65 oligodeoxynucle-otides(5′-GAACAGTTCGTCCATGGCCG-3′) was transfected into Tca8113 cells through Lepofectin vectin, then the cells were treated with 8 mg/L Pingyangmycin. After 3 h and 6 h, the expression of p65 in nucleus was studied with im-munohistochemical methods and Western blot analyses. After 48 h, the inhibitory rate of cell growth was detected with MTT assay. Results  The NF-κB/p65 signal  transduction way in Tca8113 cells was activated after treated  with Pingyangmycin. But the transfection of antisense p65 oligodeoxynucle-otides inhibited the activation of  the sig- nal transduction, the p65 expression in nucleus was decreased significantly(P<0.05) at 6 h, and the inhibitory rate of cell growth was increased significantly(P<0.05) at 48 h. Conclusion  The results suggested the chemotherapeutic sensitivity of Tca8113 carcinoma cell to Pingyangmycin was improved by the inhibition of NF-κB/p65 signal transduction.
    Study on the Effect of Concentrations of Glucose on Initial Adherence of Streptococcus mutans
    JIANG Ying1, YANG Jin-bo2, LIU Tian-jia2, TAN Hong2, HUANG Ding-ming2
    West China Journal of Stomatology. 2006, 24(05):  455-457. 
    Abstract ( 1362 )   HTML ( 2 )   PDF(pc) (34KB) ( 537 )   Save
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    Objective  To study the effect of concentrations of glucose on the initial adherence of Streptococcus mutans(S.mutans) to saliva-coated hydroxyapatite(SHA
    ), and to compare the initial adherence of S.mutans from caries-active group with that of S.mutans from caries-free group. Methods  Each 10 clinical isolates of S.mutans from caries-active and caries-free subjects were used in  this study. And S.mutans UA159 was also included in this experiment. SHA was used to simulate tooth surface in oral cavity. S.mutans clinical isolates and strain UA159  were cultured in TPY liquid medium containing 3H-TdR in the same radioactive concentration and glucose in 0.2%, 1.0%, 5.0% concentration. Then grown cells were  harvested to produce a suspension. SHA and radiolabelled bacterial suspension(A550 nm=0.52) were mixed for 90 minutes, samples were assayed by using liquid scintillation counter, and binding abilities of strains were evaluated by the count per minute(CPM). Results  The initial adherence ability of S.mutans from caries-active group was higher than that of S.mutans from caries-free group(P<0.05). And the initial adherence ability of S.mutans cultured in different concentration of glucose was also significantly different(P<0.05), 5.0% glucose group had the highest  adherence ability, and 0.2% glucose group had the lowest adherenceability. Conclusion  ①Difference of the initial adherence of S.mutans might relate to difference of carious experiences; ②Glucose may play an important role in  S.mutans initial adherence, to some extent, S.mutans cultured in the higher concentration of glucose has the higher initial adherence property.
    Effect of Erigeron Breviscapus on the Expression of Vascular Endothelial Growth Factor in the Periodontal Tissues of Rabbits during Orthodontic Tooth Movement
    LIU Chang-geng1, HUANG Sheng-gao1, LING Tian-you1, FENG De-yun2, HUANG Ping3, ZHANG Jian-xing1
    West China Journal of Stomatology. 2006, 24(05):  458-461. 
    Abstract ( 1154 )   HTML ( 2 )   PDF(pc) (174KB) ( 463 )   Save
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    Objective  To detect the effect of erigeron breviscapus on the expression of vascular endothelial growth factor(VEGF) in the periodontal tissues during
    orthodontic tooth movement. Methods  45 rabbits were divided into 3 groups(groups A, B and C). Groups A and B included experimental group of 1, 3, 7 and 14 days respectively. The mandibular first molar of each experimental rabbit was observed. The rabbits of group A and group B received iontophoresis with erigeron breviscapus  into the right(group A-R and group B-R) and with normal sodium into the left as the control(group A-L and group B-L). Additionally, the rabbits of group B were designed orthodontic appliance, by which 0.78 N mesial force was applied to pull the mandibular first molars. Group C, group of 0 day, was no iontophoresis and  orthodontic appliance as the control. After killed on schedule, the amount of experimental tooth movement was measured and the expression of VEGF was examined by  immunohistochemical method. Results  The amount of experimental tooth movement increased successively from 1 to 14 days. The differences among days 3, 7 and 14  were significant in the comparison between group B-R and group B-L(P<0.01). The expression of
    VEGF in groups A-R and B-L enhanced apparently compared with that in groups C and A-L(P<0.01), but that in group B-R was the most apparent(P<0.01). The expression of VEGF reached the peak level on day 3 in groups A-R and B-R(P<0.01), but it reached the peak level on  day 7 in group B-L(P<0.01). Conclusion  Erigeron breviscapus by iontophoresis can accelerate orthodontic tooth movement, and can meanwhile up-regulate the  expression of VEGF in periodontium in the earlier period of orthodontic tooth movement. Thus it can be presumed that one of its mechanisms for erigeron breviscapus to
    accelerate orthodontic tooth movemen is erigeron breviscapus effects the metabolism and differentiation of osteoblast and osteoclast through up-regulating the
    expression of VEGF in periodontium.
    Preliminary Study on Transformation of the Biological Function of the Cryopreserved Osteoblasts Cultured in vitro 
    TAN Wan-ye1, SUN Ming-xia2, WEI Feng-cai1, DING Guang-yao3, DONG Zuo-qing1,LIU Yun-sheng1
    West China Journal of Stomatology. 2006, 24(05):  462-465. 
    Abstract ( 1093 )   HTML ( 1 )   PDF(pc) (302KB) ( 541 )   Save
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    Objective  To culture and amplify the young rabbit′s bone marrow stromal cells(BMSCs) in vitro, and to observe the effect of hypothermia on the cells′ growing
    behavior and biological function. Methods  BMSCs were acquired from the rabbit′ tibia bone marrow and induced to mature osteoblasts in vitro. The cultured cells growing well in vitro were preserved in liquid nitrogen. The anabiotic cells having cryopreserved for 1 week were chosen as the experimental group, and the routine 7th generation as the control group. Their biological function in comparion by the examination of morphological changes, cells′ proliferation ability, colone forming ratio, synthesis ability of ALP and protein, mineralized nodes forming ability were observed. Results  As contrast to the control groups, the anabiotic cells also grew and proliferated well in vitro except a little more slowly than before. They had the similar general shape in all the time segments, but a little differences in cells′ ultrastructure. The experimental groups also had the typical characters of mature osteoblasts, and high abilities of the synthesis of ALP and proteins. The statistic data showed that these two groups had no significant difference(P>0.05). Conclusion  The cryopreserved osteoblasts had the same biological functions and the similar growing behaviors as before. These results suggest that it is practical to use the cryopreserved osteoblasts for further study on bone tissue engineering.
    Effects of Programmed Cell Death on Human Dental Follicle Cells and Changes of Programmed Cell Death under Different Hydrostatic Pressures
    IN Zuo-lin1, LUO Song-jiao2, LIN Zhu1, JIAO Guang-hai3, WANG Hai-xue1
    West China Journal of Stomatology. 2006, 24(05):  466-468. 
    Abstract ( 876 )   HTML ( 1 )   PDF(pc) (94KB) ( 412 )   Save
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    Objective  Tooth eruption requires the presence of the dental follicle(DF) around the unerupted tooth. This study is to investigate programmed cell death on
    human dental follicle cells and changes of programmed cell death under different hydrostatic pressures: 0, 50 and 100 kPa. Methods  Human dental follicles from third mandibular molars were surgically removed from adolescents who need for orthodontics treatment after informed con-tent, then trypsinized and cultured. Human dental follicle cells were divided into three groups according to different hydrostatic pressures: 0, 50 and 100 kPa and their programmed cell death were labeled by using TdT-medi-ated-dUTP nick and labeling(TUNEL). Results  Dental follicle cells cultured were elongate shape and exhibited fibroblastic
    characteristics. Compared with 0 kPa, programmed cell death cells on human dental follicle cells were increased 0.23% and 31.65% under 50 kPa and 100 kPa
    hydrostatic pressures respectively. 100 kPa group increased signnificantly (P<0.01). Conclusion  It suggested that programmed cell death occured in human dental follicle cells cultured in vitro and was influenced by different hydrostatic pressures. Hydrostatic pressure may improve tooth erup-tion through dental follicle.
    Study on Differential Estrogen Receptor β Expression of Mandibular Condylar Chondrocyte in Temporo-mandibular Joint Osteoarthritis
    FANG Ze-qiang, MA Xu-chen
    West China Journal of Stomatology. 2006, 24(05):  469-472. 
    Abstract ( 967 )   HTML ( 2 )   PDF(pc) (382KB) ( 412 )   Save
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    Objective  To test the differential Estrogen Receptor(ER) beta levels of mitochondrial proteome of mandibular condylar chondrocyte in the rat model of temporomandibular joints osteoarthritis(TMJOA). Methods  25 SD rats were divided into experimental group(15 rats) and control group(10 rats) randomly. TMJOA models were created in left sides of TMJ of 15 SD rats by the partial resection of the articular disc. The experimental rats were killed 3 months after operation. After the chondrocytes culture, Immunohistochemistry, semiquantitative RT-PCR and Western blot were used to test the differential ER beta expression levels in mitochondrial proteome of mandibular condylar chondrocytes. Mitochondrial proteins identification was carried out by two-dimensional electrophoresis and peptide mass fingerprint(PMF). Results  PMF showed that one of the differential proteins was ERβ. Immunohistoche-mistry and Western blot results suggested the significant difference of ERβ protein levels between operation-treated and control group. The operation-treated group had
    lower ERβ levels(P<0.01). Conclusion  It has been demonstrated that ERβ protein levels were decreased in mitochondria of TMJOA mandibular condylar chondrocytes, which suggests a role for mitochondrial ERβ in the effects on TMJOA. The pathological role of ERβ in the regulation of TMJOA progress remains to be elucidated.