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Table of Content
20 December 2009, Volume 27 Issue 06
  • Minimal intervention dentistry: A vision of caries management for older patients
    CHU Bing -feng, ZHANG Ying, LIU Hong-chen
    West China Journal of Stomatology. 2009, 27(06):  583-587.  doi:10.3969/j.issn.1000-1182.2009.06.001
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    The ageing of Chinese population combined with development of geriatric dentistry results in increased retention of natural teeth and higher risk of dental caries in older patients. This means new challenge for clinicians. Minimal intervention dentistry(MID) is a new approach to caries management in older patients, which emphasize on early discussion, early diagnosis and early treatment. It focuses on stopping the disease process and patient-friendly surgical intervention only when required. This article describes the application of MID in geriatric caries management: Assessment of the risk of caries; early detection(before cavity appears); external and internal remineralization.

    Establishment and application of an in vitro model for apatite crystal mineralization
    WANG Jiang, NI Long-xing, WANG Han-guo
    West China Journal of Stomatology. 2009, 27(06):  588-591.  doi:10.3969/j.issn.1000-1182.2009.06.002
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    Objective 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. Methods The model was constructed using cation selective membrane(CMV) and dialysis membrane. Double distilled water(DDW), BSA, 5, 20, 100 mg·L-1 fluoride were added into the reaction space of the model. Reaction was carried out at 37 ℃ for 3 days under gentle stirring. The crystals were identified by scanning electron microscope(SEM) and X-ray diffraction (XRD). Results 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. Conclusion It is an effective way to evaluate the influence factors of the apatite crystal mineralization by using the in vitro model.

    Effect of nano-granule titanium films on synthesis of osteoblasts
    BA Kai1, ZHANG Jing1, WANG Hu1, LIU Yuan-yuan1, YANG Zhen-yu1, LI Ming-xia1, LI Wei1, MIAO Jing-wei2
    West China Journal of Stomatology. 2009, 27(06):  592-594.  doi:10.3969/j.issn.1000-1182.2009.06.003
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    Objective To compare the synthetic ability of osteoblasts on the surface of different nano -granule titanium films and investigate the correlation between nanophase titanium films and cellular biocompatibility. Methods Four different nano-granule titanium films were produced by direct current magnetron sputtering, at ambient, 100 ℃, 250 ℃, 380 ℃ substrate temperature, respectively. Rat osteoblasts were seeded on the surface of four treated groups of titanium film samples and non-treated Ti sample(control group). The production of osteocalcin(OC) in all five groups were detected by using double antibody sandwich enzyme-linked immunosorbent assay. Results The production of OC increased gradually from day 7 to day 14 in all groups. In the control group, it showed significant differences with other five groups on day 7. On day 14, the production of OC in 100 ℃ group was the highest, and it showed significant differences with 380 ℃, control group and blank group. In 250 ℃ group, the production of OC also showed significant differences with 380 ℃, control group and blank group(P<0.05). Conclusion Titanium with nano-modified surface had good biocompatibility and different nano-granule titanium films could affect the synthesis of osteoblasts.

    Study on maternal periodontal diseases of the relationships between Porphyromonas gingivalis, serum proimmflamatory mediators and preterm low birth weight
    LIN Yao1,2, TIAN Zong-rui1, CHEN Hong-bo2, TAI Bao-jun1, JIANG Han1, DU Min-quan1
    West China Journal of Stomatology. 2009, 27(06):  595-598.  doi:10.3969/j.issn.1000-1182.2009.06.004
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    Objective To investigate the associations between periodontal diseases, presence of Porphyromonas gingivalis(P.gingivalis), serum levels of pro-inflammatory mediators and preterm low birth weight(PLBW). Methods 60 women(30 PLBW and 30 healthy women), were recruited after postpartum within 3 days in this case-control study. Periodontal measurements including plaque index(PI), bleeding index(BI), probing pocket depth(PD) and clinical attachment loss(CAL) were assessed. The subgingival plaque was collected before periodontal examination and analysed by polymerase chain reaction(PCR) for the presence of the 16S rRNA gene specific to P.gingivalis, while the venous and umbilical cord blood specimens collected were determined by enzyme-linked immunosorbent assay(ELISA). Results The PLBW cases had a poorer oral conditions and the presence of P.gingivalis was found in a higher proportion in the PLBW than the healthy pregnant(56.7% vs. 30.0%, P<0.05). Both of the presence of periodontitis and P.gingivalis have been found to be associated weakly with a shorter gestational age and a lower birth weight(P<0.05). The levels of IL-1β, IL-6 and prostaglandin-E2 ( PGE2) in both of the blood samples showed higer levels between the PLBW and normal groups(P<0.01). The IL-1β and PGE2 levels in maternal serum were higher with a severe periodontal disease in the PLBW group(P<0.01). Conclusion There may be a possible link between periodontal diseases and PLBW.

    Quantitative analysis the effect of Ciclosporin on gingival tissue modality of rats
    LIU Pei-hong, MA Su, LIU Wei-ting
    West China Journal of Stomatology. 2009, 27(06):  599-602.  doi:10.3969/j.issn.1000-1182.2009.06.005
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    Objective Quantitative analysis the regional specificity and time dependence of Ciclosporin(CsP) on gingival tissue modality of rats. Methods Eighty SPF grade male Wistar rats of 7 weeks old were randomly divided into experimental group and control group, and each group was divided into 4 subgroups according to the duration of treatment(10, 20, 30 and 40 days). The experimental objects were given intragastric administration of fresh milk including CsP, and the control ones were given intragastric administration of fresh milk the same as the experimental objects. After giving perfusion 4% paraform trans -heart to internal fixation, the specimens were get and made bucco-lingual paraffin sections at lower first molar and made HE staining. The area of buccal and lingual gingival epithelial and connective tissue, the length of the longest rete pegs were measured with the image analysis system. Data were analyzed by two-way analysis of variance of factorial design. Results The rats of the experimental group took place gingival overgrowth, and the rete pegs of gingival epithelium of attached gingiva approach muco-gingival junction were prolonged. The area of buccal and lingual gingival epithelium and connective tissue, the length of buccal longest rete pegs of the experimental group were significantly higher than that of the control group rats(bucca P<0.01, lingua 0.01<P<0.05). The length of lingual longest rete pegs of the experimental group were no difference than that of the control group rats. The area of buccal and lingual gingival epithelial, connective tissue, the length of longest rete pegs among experimental groups were no difference. Conclusion CsP may have the regional specificity on the rats′ gingival epithelium of buccal attached gingiva approach muco-gingival junction, but the effect of CsP on the rats′ gingiva was no time dependence.

    Contrasting study of erythritol and xylitol on Streptococcus mutans
    YAO Jun1, ZHANG Jia-li2, WU Yu-qiong2, LU Zhao-jie1
    West China Journal of Stomatology. 2009, 27(06):  603-605.  doi:10.3969/j.issn.1000-1182.2009.06.006
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    Objective To study the inhibitory effect of erythritol by contrast to xylitol on growth and acid production of Streptococcus mutans(S.mutans). Methods S.mutans were incubated respectively in 0.5%, 1%, 2%, 4%, 8%, 12%, 16% erythritol or xylitol culture medium under anaerobic conditions. The A and pH value of the mediums were measured at 0, 2, 4, 6, 8, 10, 12, 18, 24 hours, following the profile plots by SPSS. Results The data of A were higher in 0.5%, 1%, 2% erythritol culture medium than in xylitol culture medium at the same concentration, while lower in 8%, 12%, 16% erythritol culture medium than in xylitol culture medium at the same concentration. The data of pH were lower in 0.5% , 1% , 2% erythritol culture medium than in xylitol culture medium at the same concentration, while higer in 8%, 12%, 16% erythritol culture medium than in xylitol culture medium at the same concentration. It indicated that the growth and acid production of S.mutans were higer in 0.5%, 1%, 2% erythritol culture medium than in xylitol culture medium at the same concentration, while lower in 8%, 12%, 16% erythritol culture medium than in xylitol culture medium at the same concentration. Conclusion Compared with xylitol, erythritol in low concentration has weaker effort on the growth and acid production of S.mutans, while having stronger effort in high concentration.

    Analysis of clinical features and mutation associated with oligodontia
    WANG Jing1, JIAN Fan1, WANG Sheng1, WANG Hu2, YANG Zhi1, LIAO Zheng-yu1, LAI Wen-li1
    West China Journal of Stomatology. 2009, 27(06):  606-609.  doi:10.3969/j.issn.1000-1182.2009.06.007
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    Objective To investigate the mutation characteristics of paired box homeotic gene 9(PAX9) and muscle segment homeobox gene 1(MSX1) of patients with congenital oligodontia. Methods Clinical manifestations were recorded by taking complete oral examinations in patients with congenital nonsyndromic oligodontia and some of his normal family members. Pedigree information was confirmed by extended interviews and a pedigree was constructed. Inheritance mode and clinical features were analyzed. Assessment of crown width compared to normal value of crown width in Chinese people was based on the registrations and measurements of study cast. Comparison of craniofacial form, malocclusion types and characteristics were conducted via cephalometric analysis by taking lateral cephalometric radiographics. Venous blood samples were collected and DNA was extracted from leukocytes. DNA sequencing and mutation analysis were analyzed in exon 1, 2, 3, 4 of PAX9 and exon 1, 2 of MSX1 coding region by polymerase chain reaction(PCR). Results The teeth shape abnormality of the patient was noticed by a measured smaller crown width compared to normal values of crown width in Chinese people. The result of cephalometric analysis indicated no obvious inherited tendency in the proband in terms of facial osseo type and jaw bone pattern. One mutation was found in the proband and his mother in exon 3 of PAX9, the missense mutation G718C causing a conservative change A240P was present. Mutation was not found in MSX1. Conclusion These findings suggest that the missense mutation G718C in exon 3 of PAX9 is likely the cause of oligodontia.

    Mutation analysis of the eda-A1 gene for hypohidrotic ectodermal dysplasia and construction of recombined eukaryotic expression vector
    LEI Ke1, CHE Tuan-jie2,3, WANG Jin-ming3, DENG Ni1, ZHANG Lin1, HE Xiang-yi1
    West China Journal of Stomatology. 2009, 27(06):  610-613.  doi:10.3969/j.issn.1000-1182.2009.06.008
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    Objective The purpose of this study was to clone and analyze mutation in the eda -A1 gene for hypohidrotic ectodermal dysplasia(HED), and to construct a new recombined eukaryotic expression vector(mutant M, wild W) as a basis for further study on the genetic function. Methods After total mRNA was extracted from peripheral blood lymphocytes from the HED affect patient and control, eda-A1 gene was amplified by reverse transcription polymerase chain reaction(RT-PCR) with a pair of specific primers containing the constriction enzyme sites of BamHⅠ and HindⅢ. When the vector pcDNA3.1(-) and eda-A1(M/W) were digested by BamHⅠ and HindⅢ respectively, eda-A1(M/W) fragment was then ligated to vector pcDNA3.1(-) and the new vector was named as pcDNA3.1(-)-eda-A1-M/W. Results eda-A1 gene was successfully cloned and a novel missence mutation was identified, which changes the codon 306 from glutamine to proline. PCR, restrictive endonuclease analysis and DNA sequencing were then performed to identify the recombinant eukaryotic expression vector pcDNA3.1(-)-eda-A1-M/W, and the results were surely confirmed. Conclusion Our result indicates that the novel missense mutation in eda is associated with the isolated tooth agenesis and provide preliminary explanation for the abnormal clinical phenotype at a molecular structural level. And also, the recombinant eukaryotic expression vector pcDNA3.1 (-)-eda-A1-M/W was successfully constructed, which will be thereafter taken use of further study on eda gene in odontogenesis.

    Cloning of the fimA gene of Porphyromonas gingivalis and its expression and purification in Escherichia coli
    LIU Wei, YU Fei, CHEN Wei-min,HE Wei
    West China Journal of Stomatology. 2009, 27(06):  614-617.  doi:10.3969/j.issn.1000-1182.2009.06.009
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    Objective To clone the fimA gene of Porphyromonas gingivalis(P.gingivalis) and detect its expression in Escherichia coli(E.coli). Methods The fimA gene was obtained by PCR from the genome of P.gingivalis to construct a prokaryotic expression plasmid pT -BAD/fimA. pT -BAD/fimA was transformed into E.coli BL21(DE3) competent cells and the recombination protein was characterized by means of matrix assisted laser desorption ionisation time-offlight mass spectrometry(MALDI-TOF-MS) analysis. The bound protein was eluted with different concentrations of imidazole(250, 200, 150, 100, 50 μmol·L-1) respectively. Results DNA sequencing showed that the fragment was 99.9% consistent with that of the published. After induction with L-arabinose, a new 3.8×104 protein appeared on SDS-PAGE gel. The protein was further identified by MALDI-TOF-MS. Purity of 95% of the target protein was purified by Ni-NTA Purification System after eluted with 100 μmol·L-1 imidazole. Conclusion The fimA gene of P. gingivalis was cloned successfully and its protein was expressed correctly in E.coli. A high purity of protein FimA was obtained and it could be applied for follow-up researches.

    Distribution of Bifidobacterium in oral cavities of children and the relations with caries
    ZHAI Jing-jing1, ZOU Jing2, LU Li-ying3
    West China Journal of Stomatology. 2009, 27(06):  618-621.  doi:10.3969/j.issn.1000-1182.2009.06.010
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    Objective To explore a selected-media of Bifidobacterium from oral cavity, to detect the distribution of Bifidobacterium in different sites of children and primarily investigate the relationship between oral Bifidobacterium and early childhood caries. Methods 70 children aged from 3 to 5 -year -old were selected, 30 children were caries-free and 40 were severe early childhood caries(S-ECC). Saliva was collected and plaque samples from the 30 healthy subjects were pooled. For S-ECC group, plaques were collected separately from four different sites as follows: Saliva, surfaces of intact enamel, surfaces of white spot-lesions, and deep dentin-lesions. Samples would be grown in the selected-media, and the whole DNA of bacteria was extracted. Polymerase chain reaction was performed with specific primers and the results were analyzed by the electrophoresis. Results Bifidobacterium were detected 0 in the caries-free children, while 47.5% in the S-ECC group. There was significant difference between two groups(P< 0.05) and there was no difference between different sites of teeth in S-ECC group(P>0.05). 27.5% Bifidobacterium were detected in saliva, 27.5% on surfaces of intact enamel, 20.0% on surfaces of white spot-lesions and 22.5% in deep dentin-lesions. 10% Bifidobacterium dentium were detected in saliva, 7.5% on surfaces of intact enamel, 7.5% on surfaces of white spot-lesions and 10.0% in deep dentin-lesions. Conclusion One type of modified selected media of Bifidobacterium in oral cavity was explored. Bifidobacterium may be related to the occurrence of the S-ECC and has nothing to do with different sites of teeth in children.

    An in vitro study of the fracture strength of tooth preparations for Empress 2 veneers and crowns and mandibular incisors restored with Empress 2 veneers and crowns
    West China Journal of Stomatology. 2009, 27(06):  622-625.  doi:10.3969/j.issn.1000-1182.2009.06.011
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    Objective To compare the fracture resistance of mandibular incisors′ preparations for veneers and crowns, mandibular incisors restored with Empress 2 veneers and crowns. Methods 50 human mandibular incisors were randomly divided into five groups. Each group consisted of ten teeth and the treatment obtained as follows: A, tooth preparations for veneers; B, tooth preparations for crowns; C, teeth restored with veneers; D, teeth restored with crowns; E, untreated group. The teeth received standardized preparation and the restorations were manufactured with Empress 2 system and cemented with resin luting agent. The fracture resistances of teeth were measured by Instron universal testing machine and statistically analyzed with one-way ANOVA. Results The fracture resistances of A, B, C, D, E were (576.11±91.53), (204.13±85.88), (451.50±116.81), (386.16±117.75) and (566.05±121.37)N, respectively. The statistical analysis demonstrated significant differences between five groups. There were no significant differences between group A and E, group C and D. Conclusion Tooth preparations for veneers did not significantly reduce the fracture resistance of mandibular incisor. The fracture resistance of teeth restored with Empress 2 veneers and crowns did not significantly differ from each other.

    Clinical observation of sequential occlusal adjustment for kinetic food impaction
    XU Juan1, FANG Bi-song2, MA Hong2, SUN Xiao-qiang2
    West China Journal of Stomatology. 2009, 27(06):  626-628.  doi:10.3969/j.issn.1000-1182.2009.06.012
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    Objective To study the effectiveness of sequential occlusal adjustment for kinetic food impaction. Methods 36 patients who claiming food impaction with normal proximal contact were examined and analyzed about their occlusal relationship and configuration. Sequential occlusal adjustment was made to reduce pestle-mortar-like cusp, to create food escaping groove and to decrease mesial surface of the distal tooth cusp. One week, two weeks and six months later, the patients were reexamined and their oral conditions were evaluated. Results An elimination of food impaction was claimed for 32 patients in one week appointment and all 36 patients in two-week appointment. Six months later, no patient reported food impaction. Conclusion The use of sequential occlusal adjustment results in an effective elimination of some kind of kinetic food impaction.

    Influence of slot size on torque control
    TIAN Jun1, LIU Zhong-hao1, ZHANG Ding2, WU Chuan-jun1
    West China Journal of Stomatology. 2009, 27(06):  629-632.  doi:10.3969/j.issn.1000-1182.2009.06.013
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    Objective To study the influence of two slot size brackets on torque control when teeth interacted in the same arch. Methods After the upper arch was aligned and leveled in Typodont study, the inclinations of upper teeth 5┼5 were measured when 0.457 2 mm×0.635 0 mm OPA-K brackets and 0.558 8 mm×0.711 2 mm OPA-K brackets were filled with 0.431 8 mm×0.635 0 mm stainless steel wire. This experiment was duplicated 10 times. The inclin of each tooth were transformed to the absolute values of the torque play angle ψ by computing program, and paired-t test was used. Results The two kinds of slot size brackets were different with statistical significance on torque control. When the brackets were filled with 0.431 8 mm×0.635 0 mm stainless steel wire, the absolute values of the angle ψ in 0.558 8 mm×0.711 2 mm and 0.457 2 mm×0.635 0 mm slot size brackets were 6.140°±3.758° and 2.608°± 1.479° respectively, and the average difference of that between the two slot size brackets was 3.532°. The absolute values of the angle ψ in the upper left and right canine brackets were 2.560°±2.605°, 4.230°±2.817°, 1.260°±0.747° and 2.070°±0.663° respectively, and average differences between them were smaller than that in the other teeth. Conclusion There was difference between the two kinds of slot size brackets on torque control, and 0.457 2 mm×0.635 0 mm slot size bracket controls torque better when filled with the same size wire. In this study, the teeth interaction in the same arch probably caused the result that the difference of two slot size brackets on torque control was less than the study results of the theory calculations and material studys before.

    Preliminary study of cranio-maxillofacial hard tissue structure feature of young mandibular retrusion orthognathic patients with Delaire cephalometric analysis
    ZHOU Jie1, SONG Jin-lin1, CHEN Meng-wei2, WANG Tao1, DENG Feng1
    West China Journal of Stomatology. 2009, 27(06):  633-636.  doi:10.3969/j.issn.1000-1182.2009.06.014
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    Objective To guide the orthodontic diagnosis, treatment planning and prognosis by analyzing the craniofacial morphology and reimbursement mechanism of young patients with mandibular retrusion in Chongqing territory by Delaire cephalometric analysis. Methods Both conventional cephalometric analysis and Delaire cephalometric analysis were conducted on the basis of the lateral cephalograms from 56 young mandibular retrusion patients and 40 teenagers with normal occlusion. Results Decreases in ∠SNB, Co-Go, Co-Pog, U1-L1 and increases in ∠ANB, ∠SN -MP, L1 -MP were seen in mandibular retrusion group by conventional cephalometric analysis. Decreases in ∠1, ∠5, (Cp-Oi)/C2 and increases in ∠2, (M-Cp)/C2, ∠3, ∠4 were seen in mandibular retrusion group by Delaire cephalometric analysis. Me-F1 and Me-Met were -8.70 mm±2.48 mm and 5.74 mm±2.58 mm respectively. Conclusion Delaire cephalometric analysis could evaluate cranio -maxillofacial architectural features of mandibular retrusion patients more visually and quantitatively, which suggests that mandibular retrusion is usually caused by the retrusion of mandibular position and the hypodevelopment of mandibule.

    Analysis of treatment templates of Angle′s Class Ⅲ malocclusion patients
    LI Sa1,2, XU Tian-min1, LIN Jiuxiang1
    West China Journal of Stomatology. 2009, 27(06):  637-641.  doi:10.3969/j.issn.1000-1182.2009.06.015
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    Objective To analyze the morphological characters of Angle′s Class Ⅲ malocclusion patients and the relationship between characters and treatment options. Methods A total of 472 Class Ⅲ patients were collected during 1997 -2000. The standardized coordinates′ values of the patients were obtained by Procrustes superimposition(PS). Cluster analysis was carried out to divide the patients into different subdivisions and the relationship between treatment options and subdivisions was analyzed. Results 472 patients were divided into 14 subdivisions with special characters. The morphological templates were formed by computer. There were certain relationships between characters and treatment options. Conclusion The mechanism of malocclusion of different Class Ⅲ patients are not necessarily same. The typing has significance to choose the treatment method.

    The effectiveness of oral health education programme for middle school student to improve oral health knowledge
    LI Qing1, FAN Xu2, LI Xue2
    West China Journal of Stomatology. 2009, 27(06):  642-644.  doi:10.3969/j.issn.1000-1182.2009.06.016
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    Objective To evaluate the effect of an oral health education programme for Chinese middle school student in the rural area to improve oral health knowledge. Methods The students of two middle schools in the rural area of Deyang city, Sichuan province, were randomly choosed and divided into experiment group and control group, each group 200 students. The students of experiment group were taken oral health education based on school and brushed the teeth with fluoride toothpaste under the supervision of parents. No intervention study was given to the students of control group. Before the experiment and after 1 year, the caries and oral hygiene status were examined, and the oral health knowledge, attitude and behavior were investigated by questionnaire. Results There were no significant changes of DMFT and DMFS of experiment group after 1 year(P>0.05), while the DMFT and DMFS of control group increased obviously(P<0.05). The oral hygiene index-simplified(OHI-S) of experiment group decreased(P<0.05), while that of control group increased(P<0.05). The knowledge and the attitude towards“using fluoride toothpaste was a good way for preventing tooth decay”and “eating and drinking sweet things can cause tooth decay”, and the behavior of“brush the teeth 2 or more times a day”,“use the toothpaste containing fluoride”, “visit to dentist at least once a year”in experimental group were improved compared with control group(P<0.05). Conclusion Oral health education based on school combined the use of affordable fluoride toothpaste can improve the oral health of middle school student in the rural area.

    Color changes induced by fluoride on nickel-titanium orthodontic wires
    MA Chang-bai1, LIU Xin-qiang2, LI Jin-hua3
    West China Journal of Stomatology. 2009, 27(06):  645-648.  doi:10.3969/j.issn.1000-1182.2009.06.017
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    Objective To observe the color changes of nickel-titanium(Ni-Ti) orthodontic wires induced by fluoride. Methods Each 40 samples of 4 kinds of nickel-titanium orthodontic wires(IMD, SL, TP, YY) were put into artificial saliva with sodium fluoride at different F- concentrations (0.05%, 0.10%, 0.15%) and artificial saliva, separately. Dislodged the species and immersed them into artificial saliva with sodium fluoride for 3 minutes, then washed them with deionized water, and put back to artificial saliva, this course should be repeated 3 times per day. The whole immersion test lasted for 28 days. The color and micro-morphous changing were observed. Results The color changes came to be more serious as the F- concentration growing(P<0.05). At the same F- concentration, the color changes of IMD and YY were higher than SL and YP(P<0.01), while there were no significant difference between IMD and YY, SL and TP(P>0.05). Conclusion Fluoride can change the color of Ni-Ti wire. Different Ni-Ti wires get different changes at the same F- concentration.

    Comparison of casting precision of two kinds of commercially available gypsum-bonded investment with different setting and thermal expansion characteristics
    TONG Xu1,2,, ZHAO Yao1, MENG Yu-kun3
    West China Journal of Stomatology. 2009, 27(06):  649-652.  doi:10.3969/j.issn.1000-1182.2009.06.018
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    Objective To investigate expansion characteristics of two kinds of commercial investment(Cristo balite MicroⅡ and Cristo Quick), and their effects on cast accuracy of a dental Ag-Pd casting alloy. Methods Two kinds of investment were mixed at the ratio of 1 ∶3. The setting and thermal expansion curves of the investment were recorded according to the requirements of ISO7490 and expansion rate calculated, respectively. Plate-like wax-patterns with pre-marked points were invested in casting rings(lined with ceramic fiber liners with thickness of 0.45 mm). Castwell M.C dental alloy were melted with gas flame and cast with a centrifugal casting machine. The differences between the castings and the wax patterns at corresponding points were calculated to represent the dimensional changes of the investment. Results The setting, thermal and total expansion rates were 0.68, 1.18, 1.86 for Cristo balite MicroⅡ, and 0.94, 1.03, 1.97 for Cristo Quick. The setting and thermal expansion rates were statistically significant between two kinds of investment(P<0.05), while not for the total expansion rates(P>0.05). Effect of different investment on the precision of castings was not statistically significant(P>0.05). Conclusion Within the scope of this study, gypsum-bonded investment with similar total expansion rates but different expansion characteristics has no effect on the casting precision of Ag-Pd dental alloys.

    Culture and identify the human umbilical vein endothelial cells and investigate the expression of tyrosine kinase-2 with immunoglobulin-like and epidermal growth factor homology domains in the cells
    WU Shiqing1, ZHENG Jun-fa1, ZENG Shu-guang1, CHEN Shao-peng2, XUE Guo-chu1, ZHANG Jin-cai1
    West China Journal of Stomatology. 2009, 27(06):  653-656.  doi:10.3969/j.issn.1000-1182.2009.06.019
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    Objective To study the cultural method and identification of human umbilical vein endothelial cells (HUVECs), and investigate the expression of tyrosine kinase-2 with immunoglobulin-like and epidermal growth factor homology domains(Tie-2) in HUVECs. Methods HUVECs were isolated from umbilical veins by the technique of irrigative digestion, and were cultivated in plates. The cells were identified by Ⅷ monoclonal antibody. Tie-2 mRNA and protein were detected by reverse transcription-polymerase chain reaction (RT-PCR) and SABC immunocytochemistry. Results HUVECs could adhere to the plates completely after 24 hours, and confluence a monolayer 4-5 days later. The band of Tie-2 mRNA was obviously and the expression of Tie-2 protein was strongly positive by immunocytochemistry in HUVECs. The positive rate was over 85%. Conclusion Highly purified endothelial cells were isolated. And there were overexpression of Tie-2 in HUVECs.

    Research on cooperation between Streptococcus mutans and Lactobacilli in dental caries lesion
    ZHANG Lihuan1, SUN Tao-sheng1, WU Hong-liang2, SUN Fang-ming2
    West China Journal of Stomatology. 2009, 27(06):  657-659.  doi:10.3969/j.issn.1000-1182.2009.06.020
    Abstract ( 1217 )   HTML ( 1 )   PDF(pc) (213KB) ( 827 )   Save
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    Objective To analyze the count of Streptococcus mutans(S.mutans) and Lactobacilli(LB) in different groups and the cases in dental caries. To research the synergistic effect of S.mutans and LB in the process of dental caries. Methods 110 cases with dental caries were selected and divided according to the different degree of caries, nature and ages. To culture bacteria in the selective culture medium, then count the number of colonies. The detection rate of two kinds of bacteria in different groups, means of the bacteria count and the cariogenic cases were analyzed. Results The means of the two bacteria count increased along with the degree of caries increased(P < 0.05), and increased in the older group(P<0.05) and the active stage(P<0.05). The cases of two bacteria increased with the degree of caries increased(P<0.05), and increased in the older group(P<0.05). But there were no significant differences in evolution period and arrested caries. Conclusion The pathopoiesis capability of S.mutans and LB enhanced with the extent of caries increased. In the older group, their synergism role play a lead position. In evolution period and arrested caries, S.mutans and LB were difference only in quantity and their solo cariogenic potential all enhanced in active stage, but there were not correlation on pathopoiesis capability and active or stationary phase.

    Comparative study of cultivation of hair follicle bulge stem cell
    DONG Gang1, WANG Cheng-lin1, PENG Li1, YE Ling1,2
    West China Journal of Stomatology. 2009, 27(06):  660-664.  doi:10.3969/j.issn.1000-1182.2009.06.021
    Abstract ( 1091 )   HTML ( 1 )   PDF(pc) (378KB) ( 668 )   Save
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    Objective The purpose was to compare two different ways of culturing hair follicle bulge stem cell: The defined keratinocyte -serum free medium(DK-SFM) method and the 3T3 feeder cell method. Methods The morphological features of cultured bulge stem cells were investigated by inverted phase control microscopy. Immunostaining of stem cell marker cluster of differentiation 34(CD34) and epithelial cell marker cytokeratin 19(CK19) were performed to identify the bulge stem cell. The stemness of bulge stem cells was evaluated by colony forming efficiency (CFE) and proportion of CD34 positive cells by flow cytometry. Results Hair follicle bulge stem cells could be successfully cultivated in vitro using two methods. They were both positive for CK19 and CD34. The colony forming efficiency of hair follicle stem cell cultured in DK-SFM and the 3T3 feeder cell was 69.4% and 62.2%, respectively. There was no significant difference in colony forming efficiency between these two methods(P>0.05), while the CD34 positive cells proportion was higher in DK-SFM as 72.3% than the other as 34.7%(P<0.05). Conclusion Two methods are applicable to culture bulge stem cells in vitro. The 3T3 feeder cell method is complicated and can propagate a lot bulge stem cells from hair follicle, while the DK-SFM method is easier to get pure bulge stem cell.

    Expression of Notch1 and epidermal growth factor receptor in human tongue squamous cell carcinoma and precancerous lesion
    HUANG Hong-jie1, PING Fei-yun2, HU Ji-an3, ZHAO Shi-fang4
    West China Journal of Stomatology. 2009, 27(06):  665-668.  doi:10.3969/j.issn.1000-1182.2009.06.022
    Abstract ( 1048 )   HTML ( 3 )   PDF(pc) (592KB) ( 572 )   Save
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    Objective To investigate the expression of Notch1 in human tongue squamous carcinoma(TSCC) and precancerous lesion, and to explore the potential relation between Notch1 and epidermal growth factor receptor (EGFR). Methods The expression of Notch1 and EGFR was detected in human TSCC(n=41), tongue leukoplakia (LP)(n=39) and normal tongue mucosa(n=7) by immunohistochemistry. Results In normal tongue mucosa and LP, the positive staining of Notch1 was mainly distributed in stratum corneum, partially in stratum granulosum and stratum spinosum, but not in stratum basale, while the positive staining of EGFR was mainly distributed in stratum basale, rarely in stratum spinosum, but not in stratum granulosum and stratum corneum. In TSCC, Notch1 expression was mainly distributed in locations of squamous metaplasia, but not in peripheral cells of carcinomas, while EGFR expression was detected mainly in peripheral cells of carcinomas, but not in locations of squamous metaplasia. Conclusion Notch1 promotes the differentiation of epithelial cells in tongue mucosa and acts as a tumor suppressor in TSCC. EGFR may act as a negative regulator of Notch1 expression in epithelium of tongue mucosa and TSCC, for maintaining cell proliferation and promoting the tumorigenesis and progression of TSCC.

    Study on the compatibility of yttria-stabilized zirconia framework bonded to the corresponding veneering ceramic
    YIN Jia-yue1, ZHANG Zhong-ti1, AI Hong-jun1, SI Wen-jie2, BAO Yang1
    West China Journal of Stomatology. 2009, 27(06):  669-672.  doi:10.3969/j.issn.1000-1182.2009.06.023
    Abstract ( 1147 )   HTML ( 2 )   PDF(pc) (302KB) ( 662 )   Save
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    Objective To investigate the bonding properties and interface characterization of a domestic 3mol yttrium-stabilized tetragonal zirconium polycrystal(3Y-TZP) framework fired on with 4 different veneering ceramics for zirconia. Methods 4 different commercial veneering ceramics for zirconia(VITA VM9, SHOFU VINTAGE ZR, IPS e.max Ceram, Cercon ceram kiss) were sintered on 3Y-TZP rectangulars(15 mm×5 mm×5 mm) according to the manufacturers′ instructions for shear bond strength test, a metal-ceramic system(Ni-Cr alloy/VITA VMK95) was fabricated in the same type as a control group. Two bilayered specimens(3Y-TZP/VITA VM9, Ni-Cr/VMK95) were prepared for scanning electron microscope(SEM) and energy distribution spectrum(EDS). Results The values of shear bond strength test were (18.83±1.77)MPa for 3Y-TZP/VITA VM9, (23.83 ±7.05)MPa for 3Y-TZP/SHOFU VINTAGE ZR, (17.87±2.30)MPa for 3Y-TZP/IPS e.max Ceram, (22.26±7.45)MPa for 3Y-TZP/Cercon ceram kiss, (20.55±5.13)MPa for Ni-Cr alloy/VITA VMK95. There was no statistically significant between all-ceramic groups and the control group (P>0.05). The failure modes in all-ceramic groups showed predominately adhesive at the interface. SEM showed the 3Y-TZP/VITA VM9 contacted tightly at the interface, while EDS detected Si element diffused into 3Y-TZP material. Conclusion The results indicate that domestic 3Y-TZP has a good interface compatibility with 4 commercial veneering ceramics, as a dental framework material, it can satisfy the clinical requirements.

    Effects of C-reactive protein on chemotaxis ability of monocytes in vitro
    MENG Shu1, ZHANG Lin1, YANG He2, WU Ya-fei2, GE Song3, ZHAO Lei2
    West China Journal of Stomatology. 2009, 27(06):  673-675.  doi:10.3969/j.issn.1000-1182.2009.06.024
    Abstract ( 1104 )   HTML ( 2 )   PDF(pc) (201KB) ( 589 )   Save
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    Objective To investigate the effects of C-reactive protein(CRP) on monocytes chemotaxis ability in vitro. Methods Transwell chemotaxis assay was used to evaluate the changes of chemotactic ability of THP -1 monocytes in each group treated with CRP in different concentration. Results CRP increased the number of attracted monocytes in response to MCP-1(monocyte chemoattractant protein-1). When treated with CRP concentration at 2 μg·mL-1, the number of chemotactic monocytes increased(P<0.05). The number of attracted monocytes increased as CRP concentration was elevated(P<0.05). Conclusion CRP can increase chemotactic ability of THP-1 monocytes in concentration dependent manner.

    Expression and significance of nitric oxide synthase in mandibular distraction osteogenesis of canine
    ZHOU Nuo, LIAO Ni, WEI Shan-liang, LIANG Fei-xin
    West China Journal of Stomatology. 2009, 27(06):  676-680.  doi:10.3969/j.issn.1000-1182.2009.06.025
    Abstract ( 1063 )   HTML ( 3 )   PDF(pc) (579KB) ( 478 )   Save
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    Objective To investigate the expression and significance of nitric oxide synthase(NOS) during mandibular distraction osteogenesis and bone trauma healing, to futher study the mechanism of distraction osteogenesis. Methods Twenty-eight adult dogs were randomly divided into DO group(12 dogs), acutely lengthening group(12 dogs) and control group(4 dogs). Immunohistochemical examination were carried out to test the expression of NOS during the sixth day in distraction period, the second and eighth week of consolidation. Results In DO group infiltration of inflammatory cell was found in the distraction gap, more red blood cells(RBC) leak out around vascellum and matrix in the sixth day in distraction period. The expression of local iNOS(inducible NOS) and eNOS(endothelinal NOS) in DO gruoup and acutely lengthening group was higher than that in the control group(P<0.05), the expression of local iNOS and eNOS in acutely lengthening group was lower than that in DO group(P<0.05)in the early of distraction period and the consolidation. The expression of local iNOS and eNOS was no statistic difference between three groups(P>0.05) in the eighth week of consolidation. Conclusion NOS as a sensitive index of tissue trauma are highly expressed, and RBC was found leaking out in the early of distraction, indicating that micro-trauma to some extent may occurr during DO procedure, the micro-trauma may be one of the significant factors which increasing regeneration of bone during DO.

    Morsicatio buccarum et labiorum:Two cases report
    WANG Jia-yi1, LIU Wen-zhao2, LI Xiao-ying1, LI Zhangwei1, ZENG Xin1
    West China Journal of Stomatology. 2009, 27(06):  681-682.  doi:10.3969/j.issn.1000-1182.2009.06.026
    Abstract ( 2038 )   HTML ( 45 )   PDF(pc) (184KB) ( 2231 )   Save
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    Morsicatio buccarum et labiorum is a form of chronic oral mucosa disease caused by habitual cheek or lip biting. The affected mucosa shows a shredded appearance. The patients may feel their oral mucosa rough. In present, there have not been unified denomination and systematic introduction about this disease in our country. Two cases were reported here. The pathogenesis, clinical manifestation, pathology, diagnosis, differential diagnosis, treatment and prognosis about this disease were also discussed.

    The oral exosyndrome and diagnosis of 3 patients with acquired immune deficiency syndrome
    LI Zhangwei1, LI Xiao-ying1, LIU Wen-zhao2, WANG Jia-yi1, ZENG Xin1
    West China Journal of Stomatology. 2009, 27(06):  683-685.  doi:10.3969/j.issn.1000-1182.2009.06.027
    Abstract ( 1322 )   HTML ( 2 )   PDF(pc) (245KB) ( 1847 )   Save
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    The aim of the report is to increase the dentists′, vigilance to the acquired immune deficiency syndrome (AIDS) by means of analyzing the oral exosyndrome and discussing the experience of diagnosis to 3 patients with AIDS. Vigilance to AIDS can make us to discover, diagnose and treat it in the early stage, and prevent us from transmission of the disease.

    Root canal treatment of mandibular first premolar with 3 root canals: A case report
    AN Kang-kang, ZHAO Shou-liang
    West China Journal of Stomatology. 2009, 27(06):  686-686.  doi:10.3969/j.issn.1000-1182.2009.06.028
    Abstract ( 1520 )   HTML ( 2 )   PDF(pc) (72KB) ( 389 )   Save
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    The occurrence of three canals in mandibular premolars is very rare. This article reported and discussed the treatment of a mandibular first premolar with 3 root canals, specially in aspect of root-detecting and root-shaping.