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20 December 2017, Volume 26 Issue 6 Previous Issue    Next Issue

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Study of endoplasmic reticulum stress response in osteogenic differentiation of human periodontal ligament cells LI Li-fen, WEN Yang, JIANG Long, ZHU Ya-qin 2017, 26 (6):  577-581.  doi: 10.19439/j.sjos.2017.06.001 Abstract ( 351 )   PDF (3585KB) ( 237 )   PURPOSE: The aim of this study was to establish whether endoplasmic reticulum (ER) stress is involved in osteogenic differentiation of periodontal ligament cells (PDLCs) and to better understand the mechanism of PDLCs osteogenic differentiation. METHODS: PDLCs were isolated from extracted teeth and cultured in presence or absence of osteogenic medium, which can induce osteogenic differentiation of PDLCs. Alkaline phosphatase and alizarin red S staining were performed to characterize the osteogenic differentiation of PDLCs. The mRNA and protein levels of ER stress markers were examined by RT-PCR and Western blot analysis. The data were analyzed with SPSS 17.0 software package. RESULTS: Cell treated with osteogenic medium showed increased expression of alkaline phosphatase, increased matrix, and mineralized nodule formation compared with untreated controls. Treatment with osteogenic induction resulted in up-regulation of genes, such as splicing x-box binding protein-1 (sXBP1), activating transcription factor 4 (ATF4) and glucose-regulated protein 78 (GRP78). The expressions of ER stress protein markers, phosphorylated RNA-activated protein kinase-like ER-resident kinase (p-PERK), phosphorylated eukaryotic initiation factor-2α (p-eIF2α), increased in osteogenic induction cells compared with controls. CONCLUSIONS: The results indicate that ER stress response is involved in the process of osteogenic differentiation of PDLCs. References | Related Articles | Metrics

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Expression pattern of Krüpple-like factor 5 in odontoblasts DU Jian-xin, HU Wei 2017, 26 (6):  582-585.  doi: 10.19439/j.sjos.2017.06.002 Abstract ( 231 )   PDF (2967KB) ( 123 )   PURPOSE: To investigate the expression of Krüpple-like factor 5 (KLF5) in human pulp-dentin complex and the function of KLF5 in differentiation and dentinogenesis of odontoblasts. METHODS: Immunohistochemistry staining was used to investigate the expression of KLF5 in human pulp-dentin complex and dental pulp cells. Western blot was used to analyze the expression patterns of KLF5 during dental pulp cell differentiation. Significant differences between groups were evaluated using one-way ANOVA and Tukey's test with SPSS17.0 software package. RESULTS: Immunohistochemical staining showed KLF5 was positively expressed in the odontoblasts and odontoblast-like cells, but not in dentin and predentin in both normal and carious teeth. Moreover, during mineralization of human dental pulp cells, KLF5 was primarily localized in the nuclei of dental pulp cells. Western blot showed KLF5 was significantly up-regulated during odontoblast differentiation. CONCLUSIONS: KLF5 may play an important role in odontoblast differentiation and dentin formation. References | Related Articles | Metrics

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Effect of ball attachments with different materials on retention of mandibular implant supported overdenture SHE Wen-jun, HE Jia-jing, LIU Yun-jia, JIAO Ting 2017, 26 (6):  586-589.  doi: 10.19439/j.sjos.2017.06.003 Abstract ( 331 )   PDF (3119KB) ( 151 )   PURPOSE: To investigate the effect of ball attachments with different materials on retention of mandibular implant supported overdenture. METHODS: The experimental groups were divided into group A (titanium ball / titanium cap group) and group B (titanium ball / golden cap group), each group had 3 samples. A standard mandibular edentulous model was made, and the implants (4.8*10 RN SP) were embedded in the bilateral canine region. Mandibular complete dentures were made routinely and the attachments were attached. Five thousand times of insertion-separation cycles were carried out. After 200 times of cycles, the retention force was tested. The difference between 2 groups was compared by using SPSS 13.0 software package. The change of positive structure surface morphology was observed under scanning electron microscope at the beginning and the end of the experiment. RESULTS: The retention force of group A decreased from （27.00±0.16） N to （4.18±0.03） N, and the retention force of group B decreased from （21.58±0.06） N to （19.15±0.06）N. Decay of retention of group A was significantly greater than that of group B. At the end of the experiment, the globular structure of group A was severely broken, while a smooth and clear spherical structure was displayed in group B. CONCLUSIONS: The retention of mandibular implant supported overdenture decreases with the increase of insertion-separation times. The decay of retention force is related to destruction of positive structure surface. The fatigue resistance of the precious metal material is better. References | Related Articles | Metrics

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Experimental research of hot alkaline solution etching treatment on zirconia/resin bonding strength WAN Li-yang, ZHU Hong -shui 2017, 26 (6):  590-593.  doi: 10.19439/j.sjos.2017.06.004 Abstract ( 352 )   PDF (2907KB) ( 239 )   PURPOSE: In this experiment, we applied hot alkaline solution (20%NaOH solutions) to treat the surfaces of zirconia ceramics in vitro, then evaluated the changes of bond strength of zirconia ceramics and resin cement. METHODS: Eighteen pieces of zirconia ceramic specimens were made, using the same method of grinding and polishing, and then randomly divided them into 3 groups: group A with hot alkali solution treatment (20%NaOH) (n=6), group B underwent sand blasting with a diameter of 110 μm alumina particles (n=6), group C was as the control group. Atomic force microscope was used to measure the roughness of the surface of the specimens, and the zirconia surfaces were scanned to get topography maps, then made them into ceramic/resin-bonded specimens. After 24 h of water reservoir processing, shearing bonding strength (SBS) test was conducted and their bond interfaces were observed to investigate the lesions of different degree in these specimens. The data were analyzed with SPSS20.0 software package. RESULTS: Surface roughness was group B> group A > group C, SBS was group B>group A>group C. CONCLUSIONS: Under the condition of 180℃, bonding strength between zirconia and resin cement after treatment with 20% NaOH solution was significantly higher than without any treatment, but lower than sand blasting treatment. References | Related Articles | Metrics

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Cytotoxicity of 3 resin cements to human gingival fibroblasts ZHANG Chang-yuan, NIU Gang, JIN Yi-yi, YU Hao, CHENG Hui 2017, 26 (6):  594-598.  doi: 10.19439/j.sjos.2017.06.005 Abstract ( 786 )   PDF (3785KB) ( 176 )   PURPOSE: To study the cytotoxicity of 3 resin cements to human gingival fibroblasts (HGFs). METHODS: Three resin cements (Panavia F, RelyXTM Unicem and Multilink Speed) test samples were immersed and incubated in the culture medium for 48 h at 37℃. Cultured HGFs were exposed to two concentrations (50% and 100%) of material elutes for 24 h, 72 h and 120 h. The proliferation rate was evaluated using CCK-8 assay. The data were statistically analyzed by one-way analysis of variance using SPSS 20.0 software package. RESULTS: Relative growth rate(RGR) of all experimental groups ranged from 10.67% to 100.02%, the cytotoxicity grade of all groups was 0 to 4. There was no significant difference in the RGR among 3 resin cements, but the experimental group of Panavia F (uncovered with antioxidant) showed significantly lower RGR than other experimental groups. CONCLUSIONS: Panavia F, RelyXTM Unicem and Multilink Speed exhibit no cytotoxicity to HGFs, Panavia F(uncovered with antioxidant) shows moderate cytotoxicity. References | Related Articles | Metrics

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Klf10 silencing inhibited mechanical force induced osteogenic differentiation of human periodontal ligament cells YU Xiao-qin, LI Yun-long, Gao Jin-yu, LIU Hua 2017, 26 (6):  599-604.  doi: 10.19439/j.sjos.2017.06.006 Abstract ( 312 )   PDF (4318KB) ( 204 )   PURPOSE: To investigate the effect of Klf10 silence on human periodontal ligament cells (HPDLCs) under mechanical force. METHODS: HPDLCs were isolated and transfected with Klf10 siRNA, and then exposed to centrifugal force for 6 h at 631 r/min. Purmorphamine, an hedgehog signaling pathway agonist, was used for intervention. The activity of alkaline phosphatase (ALP) was detected by ELISA. RT-PCR and Western blot were performed to detect the mRNA and protein expression of Klf10, Runt related transcription factor 2 (Runx2), osteopontin (OPN) and osteocalcin (OCN). The protein expression of glioma associated oncogene homolog 1 (Gli1) and patched-1 (PTCH1) was detected by Western blot. SPSS 20.0 software package was used to analyze the data. RESULTS: Mechanical force increased mRNA and protein level of Klf10, Runx2, OPN and OCN, and elevated ALP activity significantly (P<0.05). Mechanical force also upregulated the protein expression of GLI1 and Ptch1 significantly (P<0.05). Compared with the control group, Klf10 siRNA transfection significantly decreased mRNA and protein level of Klf10 (P<0.05). Klf10 siRNA significantly inhibited the activity of ALP, and downregulated mRNA and protein expression of Runx2, OPN and OCN (P<0.05). Moreover, Klf10 siRNA significantly inhibited protein expression of GLI1 and Ptch1 (P<0.05), and purmorphamine obviously inhibited the effect of Klf10 siRNA (P<0.05). CONCLUSIONS: Klf10 silencing could inhibit bone differentiation of human periodontal ligament cells under mechanical force, which may be through regulation of hedgehog signaling pathway. References | Related Articles | Metrics

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Retrospective analysis of 896 cases of parotid gland tumor ZHAO Zhi-guo, GAO Dan, WANG Jin, ZHANG Li-ping 2017, 26 (6):  605-609.  doi: 10.19439/j.sjos.2017.06.007 Abstract ( 666 )   PDF (3764KB) ( 408 )   PURPOSE: To review the clinical data of patients undergoing operation, in order to summarize the incidence, proportion, clinical examination and diagnostic methods of parotid tumors. METHODS: Eight hundred and ninty-six cases of parotid gland tumors were collected from 2008 January to 2015 July from department of oral and maxillofacial surgery in Shengjing Hospital of China Medical University. A retrospective study of the clinical data was carried out, including age, gender, tumor location, diagnostic methods and pathological results. RESULTS: In 896 patients with parotid gland tumor, 432 were male, 464 were female, the ratio was 1:1.07; 431 cases were on the left side, 454 cases were on the right side, 11 cases were bilateral; The proportion of parotid tumor was higher in patients aged 31 to 70 years old. 786 cases were benign, 110 cases were malignant, the ratio of benign to malignant was 7.15:1. Pleomorphic adenoma, Warthin tumor and basal cell adenoma were the most common types of benign tumors, while mucoepidermoid carcinoma, acinic cell carcinoma and adenoid cystic carcinoma accounted for the most of malignant tumors. CONCLUSIONS: The pathological types of parotid gland tumor are complicated. Clinical examination and imaging features are helpful to diagnosis. The accuracy is high in diagnosis of parotid gland tumor by frozen section, which is useful to assist making treatment plan. References | Related Articles | Metrics

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Clinical research for non-extraction treatment of maxillary mild-to-moderate crowding with Damon technology ZHANG Wei, YAN Chuan-jie, LI Li 2017, 26 (6):  610-614.  doi: 10.19439/j.sjos.2017.06.008 Abstract ( 480 )   PDF (3621KB) ( 210 )   PURPOSE: To compare the clinical efficacy of non-extraction treatment in maxillary mild-to-moderate crowding cases with Damon self-ligating system and Roth traditional brackets. METHODS: Sixty skeletalⅠorthodontic patients were selected in this study. They were divided into DamonⅠ, RothⅠ, DamonⅡ and RothⅡ group according to the bracket species and maxillary crowding degrees. Lateral cephalometric radiographs and models were measured before and after aligning and leveling to analyze the changes in dental arch and soft and hard tissue using SPSS 19.0 software package. RESULTS: After non-extraction treatment of cases with mild (Ⅰ) crowding, significant increase was found in dental width ,dental length and upper incisor torque produced by two brackets. However, there was no significant difference between the two groups. After non-extraction treatment of cases with moderate(Ⅱ) crowding, the width of maxillary canines (1.81 mm) and premolars (2.29 mm) of Damon Ⅱ group were significantly greater than those of Roth Ⅱ group (1.66 mm, 1.80 mm) (P<0.05). The changes of arch length (3.19 mm)and upper incisor torque (9.1°) in Damon Ⅱ group were significantly less than those in Roth Ⅱ group (3.85 mm, 14.5°). There was no significant difference of increased widths between maxillary molars in the two groups. CONCLUSIONS: With the increase of maxillary crowding level, the advantages of expansion and controlling the torque of anterior teeth are more obvious in non-extraction treatment using Damon self-ligating system. References | Related Articles | Metrics

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Expression and correlation of HPV16E6 and tumor suppressor gene p53 in oral squamous cell carcinoma LI Huai-qi, WU He-ming, DING Xu, YE Jin-hai, WU Yu-nong 2017, 26 (6):  615-618.  doi: 10.19439/j.sjos.2017.06.009 Abstract ( 293 )   PDF (2728KB) ( 225 )   PURPOSE: To exploring the expression of PV16E6 gene and p53 gene in patients with oral carcinoma and the correlation between pathological grade and clinical stage of oral cancer and expression of HPV16E6 gene and p53 gene. METHODS: One hundred and seventy-three cases of oral cancer, 98 cases of oral precancerous lesions and 79 cases of peri-cancerous normal tissue were selected. The expression of HPV16E6 and p53 was detected by immunohistochemistry. The data were analyzed using SPSS 21.0 software package. RESULTS: In oral carcinoma, the expression rate of HPV16E6 was 81.5% (141/173), the expression rate of p53 was 23.7% (41/173); in oral precancerous lesions, the expression rate of HPV16E6 was 39.8% (39/98), the expression rate of p53 was 57.1% (56/98); in peri-cancerous normal tissues, the expression rate of HPV16E6 was 2.5%(2/79), the positive expression rate of p53 was 89.9%(71/79). There was significant difference in the positive expression rate of p53 and HPV16E6 among 3 groups. The expression of HPV16E6 in oral cancer was significantly higher than in the other two groups(P<0.05); the expression rate of p53 in oral cancer was significantly lower than the other two groups. In addition, with the advance of clinical stage and pathological grade, the positive expression rate of HPV16E6 increased gradually, while the positive expression rate of p53 was significantly decreased (P<0.05). CONCLUSIONS: HPV16E6 protein and p53 protein may play an important role in the occurrence and progress of oral cancer. References | Related Articles | Metrics

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Clinical observation on different kinds of laser on 60 molars with abrasion SUN Hai-yan, QIU Li-hong, YANG Di 2017, 26 (6):  619-622.  doi: 10.19439/j.sjos.2017.06.010 Abstract ( 295 )   PDF (3118KB) ( 192 )   PURPOSE: To evaluate the clinical effect of different kinds of laser on 60 molars with abrasion. METHODS: Thirty patients with 60 abrasive molars were selected according to the inclusion criteria. Molars and premolars were divided into 2 groups randomly. Teeth in the experimental group were treated with Er,Cr:YSGG laser combined with AdperTM Easy One, while teeth in the control group were treated with Nd:YAG laser combined with AdperTM Easy One, composite resin Z350 was selected to restore the defect. The modified USPHS criteria was used to evaluate the treatment effects at recall periods.The data were analyzed using SPSS 13.0 software package. RESULTS: On retention, the B level rate of the experimental group was significantly lower than that of the control group(P<0.05) 12 months later. For success rate at 18 months,the difference between the experimental group and the control group was significant（P<0.05）. At the same time, sensitivity of tooth and overall response in the two groups had no significant difference (P>0.05). CONCLUSIONS: Although the overall response between the two groups had no significant difference,Er,Cr:YSGG laser shows better effect of retention, which is the preferred option for treatment of abrasive molars. References | Related Articles | Metrics

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Study of three-dimensional anatomical relationship between infrazygomatic crest and maxillary sinus for mini-screw insertion WANG Peng, CHEN Zheng-xi, WU Jun, CHEN Zhen-qi 2017, 26 (6):  623-627.  doi: 10.19439/j.sjos.2017.06.011 Abstract ( 875 )   PDF (3653KB) ( 416 )   PURPOSE: To measure the thickness of the infrazygomatic(IZ) crest above the maxillary first molar and analyze its relationship with maxillary sinus as to derive clinical implications and provide guidance for placements of orthodontic mini-screw. METHODS: Thirty seven cone-beam CT(CBCT) images of infrazygomatic crest sites were collected from data of 19 adult inter-treatment orthodontic patients. Based on the relationship of maxillary sinus floor and mesiobuccal root of the maxillary first molar, the subjects were divided into high sinus floor group (n=13) and low sinus floor group (n=24). Both lengths of mesial and distal buccal root of the maxillary first molar were measured as a reference for mini-screw positioning. Statistical analysis of the data was conducted using SPSS 20.0 software package. RESULTS: IZ crest thickness above the maxillary first molar in high sinus group was larger than that in low sinus group, and the thickness decreased as the measurement moved towards the skull base in both groups. Lengths of mesial and distal buccal root of the maxillary first molar were (12.62±0.55)mm and (12.30±0.48)mm respectively in male patients alongside (11.53±0.24)mm and (11.15±0.26)mm respectively in female patients. CONCLUSIONS: Our data indicated pre-insertion evaluation of the appropriate level of maxillary sinus floor should be performed before placement of mini-screw using CBCT. In order to avoid injury to the mesiobuccal root of the maxillary first molar and enhance the stability of inserted miniscrew, positions for miniscrew implant insertion should be over 13.62 mm in Chinese male patients and 12.53 mm in female patients at the vertical level from buccal CEJ. References | Related Articles | Metrics

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Application of Nd:YAP laser in dental pulp revascularization LIU Xian, YAO Yun-feng, XU Xin-Yi 2017, 26 (6):  628-632.  doi: 10.19439/j.sjos.2017.06.012 Abstract ( 416 )   PDF (3623KB) ( 226 )   PURPOSE: To compare the effect of Nd:YAP laser and Hoshino's triple antibiotic paste on root canal disinfection in the treatment of pulp revascularization, and to provide reference for root canal disinfection in dental pulp revascularization. METHODS: Forty immature permanent teeth diagnosed as acute or chronic periapical periodontitis were included. The periapical lesions and root development were recorded. The cases were divided into 2 groups: the control group and the Nd:YAP laser disinfection experimental group. Clinical examination and X-ray evaluation of each case were performed after treatment. Statistical analysis was performed using SPSS 19.0 software package. RESULTS: Two cases showed symptoms in control group 1 week after treatment, while 4 cases had symptoms in the experimental group. The clinical symptoms disappeared in the control group 2 weeks after treatment, while 1 case still had symptoms in the experimental group. There was no significant difference between the two groups (P>0.05). Clinical evaluation at 18 months of follow-up showed that 2 and 3 cases had recurrent symptoms in the control group and the experimental group, respectively; continuous development of the root was noted in 12 and 10 cases on X-ray film in the control and experimental group, respectively, while 3 and 4 teeth had no obvious root development in the control and experimental group, respectively. There was no significant difference between the control group and the experimental group (P>0.05). CONCLUSIONS: Nd:YAP laser can be used for effective root canal disinfection without obvious effect on the prognosis of dental pulp revascularization. References | Related Articles | Metrics

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Clinical evaluation of simple maxillary sinus elevation with simultaneous implant in patients with serious posterior maxillary deficiency JIANG Yin-hua, TAO Hai-biao, JIN Xiao-ming, LI Xiao-kun 2017, 26 (6):  633-636.  doi: 10.19439/j.sjos.2017.06.013 Abstract ( 331 )   PDF (2755KB) ( 205 )   PURPOSE: To evaluate the clinical effect of simple osteotome sinus floor elevation without bone grafting in the posterior maxilla area with less bone height. METHODS: Twenty eight cases with posterior maxillary bone deficiency were included.Their residual alveolar bone height (RBH) was less than 7 mm. 40 ITI implants were implanted. Among them, 6 implants were implanted in the sites with RBH less than 4 mm (group 1), 34 were implanted in the sites with RBH between 4 to 7 mm (group 2).16 implants were inserted with bone graft, while 24 implants were inserted without bone graft. 6~12 months after operation, the alveolar bone height were measured and recorded. SPSS19.0 software package was used for data analysis. RESULTS: All 40 implants in 28 patients had good initial stability and good osseointegration, the success rate was 100%. RBH in group 1 and group 2 was (3.44±0.57) mm, (5.50±1.00) mm, respectively; postoperative bone increase was (7.91+1.06) mm in group 1, (8.77+1.15) mm in group 2, respectively (P>0.05).Preoperative RBHin bone graft group was (5.37±1.24) mm and (5.07±1.19) mm in patients without bone graft. Postoperative bone increase was (8.47±1.18) mm in bone graft group, and (8.89±1.13)mm in patients without bone graft, responsively (P>0.05). CONCLUSIONS: Maxillary sinus elevation can be successfully performed in patients with RBH<4 mm, and the effect is similar to that of conventional maxillary sinus lifting. Simple osteotome sinus floor elevation without bone grafting, which is with less trauma and lower cost, is effective in improving bone height in posterior maxillary region. References | Related Articles | Metrics

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Evaluation of nutrition risk and analysis of relative factors of patients with oral and maxillofacial cancer LIU Ying, JIN Wu-Long 2017, 26 (6):  637-640.  doi: 10.19439/j.sjos.2017.06.014 Abstract ( 228 )   PDF (2730KB) ( 179 )   PURPOSE: To evaluate the potential nutrition risk and analyze relative factors in patients with oral and maxillofacial cancer, and explore the treatment method of nutrition risk. METHODS: Eighty eight patients with oral and maxillofacial cancer were included in the present study. Their age, height, weight, clinical classification, level of hemoglobin、albumin and prealbumin,present treatment were recorded and patients' body weight index (BMI) was calculated and scored based on a table of nutrition risk evaluation. The data were analyzed using SPSS 17.0 software package. RESULTS: In 88 cases of patients with oral and maxillofacial cancer, 18 patients had malnutrition (BMI<18.5 kg/m2), accounting for 20.45%; 49 patients had nutrition risk (NRS2000≥3 points), accounting for 55.68%. CONCLUSIONS: Patients with oral and maxillofacial cancer had high nutrition risk. The older the age, the higher the nutrition risk will be. Anemia, low albumin and low prealbumin will increase the incidence of nutrition risks. References | Related Articles | Metrics

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Evaluation of effects of fluoride varnish on prevention of first permanent molar caries ZHANG Lu-dong, ZHOU Yin, ZHU Ya-qin 2017, 26 (6):  641-645.  doi: 10.19439/j.sjos.2017.06.015 Abstract ( 451 )   PDF (3683KB) ( 217 )   PURPOSE: To compare fluoride varnish and fluoride foam's effectiveness of preventing first permanent molar caries, and discuss patients' acceptance of the 2 materials among pupil patients. METHODS: Six hundred pupils aged 6~8 years from 3 primary schools in Shanghai Yangpu District were randomly selected.The subjects were randomly divided into 3 groups, with 200 students having 800 teeth in each. Two of these groups were experimental groups that receive fluoride varnish (Group A) and fluoride foam (Group B) respectively, and the third group (group C) was control group.Pupils in group A and group B received 2.26% Toro fluoride fluoride varnish, 1.23% fluoride foam was applied to the first molars. In the next 2 years, all pupils received dental health education every half year. The pupils' conditions of first permanent molar caries were checked in the sixth, twelfth, eighteenth and twenty-fourth month since the study started. Statistical analysis was performed using SPSS 10.0 software package. RESULTS: After 6 months, there was no significant difference between the 3 groups (P>0.05), the rate of caries incidence in the experimental group B was significantly higher than group A during the observation period after 12 months (P<0.05). Caries incidence in both group A and B was lower than the control group, with significant difference (P<0.05). CONCLUSIONS: Both duraphat fluoride varnish and fluoride foam prove to be effective in caries prevention. Moreover, considering other factors such as safety, convenience and cost, fluoride protector will be an even better choice in practical use. References | Related Articles | Metrics

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Clinical analysis of spectrum CT imaging reducing metal artifacts of oral and maxillofacial region SUN Qi, DONG Min-jun, YANG Xing, JIANG Meng-da, TAO Xiao-feng 2017, 26 (6):  646-649.  doi: 10.19439/j.sjos.2017.06.016 Abstract ( 399 )   PDF (3069KB) ( 247 )   PURPOSE: To assess the capability of monochromatic energy images of gemstone spectral imaging(GSI) by using spectral CT in reducing metal artifacts of oral and maxillofacial region. METHODS: Spectral CT imaging was applied to 46 patients with metallic implants with GSI sequence to measure CT numbers (expressed in Hounsfield units, HU) and SD (standard deviation) numbers of the soft tissues. 11 monochromatic-image groups were obtained, ranging from 40 keV(kiloelectronvolts) to 140 keV (every 10 keV as one group). The data were analyzed with SPSS19.0 software package. RESULTS: Images in 20 subjects with orthodontic appliance, the minimal average AI ranged between (23.86±10.90) to (24.42±11.54) HU. Similarly, in 12 subjects with titanium implants, the minimal average AI ranged between (26.49±9.40) to (26.95±8.97) HU. In 10 images from 14 subjects with dental fillings or fixed dentures, the minimal average AI ranged between (29.84±13.04) to (30.97±13.15) HU. The average AI values were (63.36±70.52), (70.82±105.14) and (107.35±147.57) HU from 40 keV to 140 keV in 3 groups, respectively, which was similar to the average AI values of 70keV monochromatic images (61.46±32.06, 70.18±62.86, 110.28±78.70) HU in each corresponding group. There was a significant difference about AI value among 3 energy spectrum groups (P<0.05). CONCLUSIONS: Spectral CT imaging could obviously reduce metal artifacts, and improve the display capabilities of the structures around the metallic implants. 70 keV is the dividing point of metal artifact subtraction. The optimal energy range is at 110-140 keV in reducing metal artifacts of oral and maxillofacial region. References | Related Articles | Metrics

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Survey on dental caries status of migrant children aged 6-12 years in Minhang district of Shanghai XU Xiao-ming, SHI Hong-yan, LI Cong-hua, NIE Li, FENG Lin, QIN Yan 2017, 26 (6):  650-653.  doi: 10.19439/j.sjos.2017.06.017 Abstract ( 247 )   PDF (2343KB) ( 205 )   PURPOSE: To investigate the prevalence of dental caries among migrant children aged 6-12 years in Minhang district of Shanghai, so as to provide some basic data for children health care. METHODS: Ten thousand and eleven school children in 8 primary schools of Minhang district of Shanghai were investigated by cluster random sampling. Visual examination combined with probe inspection was used to diagnose caries, and then rate of caries and DMFT (decayed,missing and filled teeth) were calculated. SPSS 13.0 software package was used for statistical analysis. RESULTS: The prevalence of caries among children aged 6-12 years was 67.07%, which was significantly higher than that in children from government-owned schools (61.99%)(P<0.01). The prevalence of caries was 75.82% in 6-year-old group and highest compared to other groups. CONCLUSIONS: It can't be optimistic about the caries prevalence among migrant children aged 6-12 years in Minhang district,Shanghai.More attentions should be payed in prevention and early intervention of dental caries for children above 6 years old. References | Related Articles | Metrics

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Effect of rhEGF on the levels of serum EGF and inflammatory cytokines in patients with oral and maxillofacial trauma YIN Zhi-fa, WANG Si-ming 2017, 26 (6):  654-657.  doi: 10.19439/j.sjos.2017.06.018 Abstract ( 209 )   PDF (2833KB) ( 155 )   PURPOSE: To investigate the effect of debridement combined with recombinant human epidermal growth factor (rhEGF) on wound healing, scar formation, serum epidermal growth factor and inflammatory factors in patients with oral and maxillofacial trauma. METHODS: Eight-two cases with oral and maxillofacial trauma treated in our hospital (January 2015 to December 2016) were retrospectively analyzed. All patients received routine treatment, 41 received rhEGF besides routine treatment (experimental group), 41 patients received only cosmetic debridement and suturing (control group). The effect, wound healing time of 2 groups were recorded and compared. The serum epidermal growth factor, interleukin -6 (IL-6), tumor necrosis factor alpha (TNF-α) and interleukin -1 (Interleukin-1, IL-1) before and after operation were compared between 2 groups. SPSS16.0 software package was used to analyze the data. RESULTS: The average wound healing time of the patients in the experimental group was 5.1±1.3 days, and the average wound healing time of patients in the control group was 7.4±1.9 days, the difference between 2 groups was statistically significant (t=6.397, P<0.01). The effective rate of the experimental group was significantly higher than the control group (P<0.05). Before operation, the serum epidermal growth factor, IL-6, TNF-α and IL-1 in 2 groups had no significant differences (P>0.05); 2 days and 5 days after operation, the serum epidermal growth factor level of the experimental group was significantly higher than the control group(P<0.05). The serum IL-6, TNF-α , IL-1 level of the experimental group were significantly lower than the control group(P<0.05).The side effects happened in the experimental group were significantly lower than control group (P<0.05). CONCLUSIONS: Patients with oral and maxillofacial trauma treated by debridement combined with rhEGF can promote wound healing and reduce the degree of inflammation. References | Related Articles | Metrics

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Changes of soft tissues in patients with functional and skeletal Angel Class Ⅲ malocclusion after FRⅢ appliance therapy ZHANG Nan, WANG Sun, FAN Lin-feng, CHEN Xiao-min, LI Xiao-xin 2017, 26 (6):  658-661.  doi: 10.19439/j.sjos.2017.06.019 Abstract ( 378 )   PDF (3033KB) ( 186 )   PURPOSE: To compare the changes of soft tissues before and after treatment of functional and skeletal Angle class Ⅲ malocclusion with FRⅢ appliance. METHODS: Thirty patients with functional and skeletal Angel Class Ⅲ malocclusion were selected and treated with FRⅢ appliance,SPSS 22 software package was used to analyzed soft tissue changes before and after treatment. RESULTS: After treatment, FCA,NLA, Pog labial angle,upper lip to E line were increased significantly (P<0.05). Z angle was decreased significantly (P<0.05). Lower lip to E line was decreased significantly (P<0.01). There was no significant difference in H angle, superior sulcus depth, inferior sulcus to H-line, basic upper lip thickness, upper lip strain measurement (P>0.05). CONCLUSIONS: After FRⅢ appliance treatment of Angel Class Ⅲ malocclusion, the convexity of facial profile was increased, type Ⅲ concave profile tends to be flat, the facial profile of patient become more attractive; the protrusion of upper lip was found, the retrusion of lower lip was also present, the convexity of upper lip was increased. References | Related Articles | Metrics

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Effects of ultra thin porcelain veneers in repair of anterior teeth gaps HONG Yu-rui, XIE Xiao-ling, LUO Wei-yan 2017, 26 (6):  662-665.  doi: 10.19439/j.sjos.2017.06.020 Abstract ( 313 )   PDF (2733KB) ( 221 )   PURPOSE: To evaluate the clinical effect of ultra thin porcelain veneers in the repair of the anterior teeth gaps. METHODS: The anterior teeth gaps in 42 patients were repaired from 2013 to 2014 with ultra thin porcelain veneers ,the clinical results of 145 porcelain veneers were evaluated at 6,12 ,24 and 36 months after repair. RESULTS: Thirty six months after repair, 145 ultra thin porcelain veneers were successful retained, 99.3% veneers were found to be intact .Small wane existed in one veneer at the incisal areas. 98.6% teeth had acceptable marginal adaptation .Few teeth had little hyperesthesia of dentin early after repair, but disappeared after 12 months. Patients were satisfied with the colour and shape of veneers. CONCLUSIONS: Ultra thin porcelain veneer is an satisfactory method to quickly repair anterior teeth gap. References | Related Articles | Metrics

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Treatment of 48 cases of benign lower posterior tumor of the parotid gland with C-shaped small incision GAO Zhen-ran, MA Song-bo, ZHANG Guo-qin 2017, 26 (6):  666-668.  doi: 10.19439/j.sjos.2017.06.021 Abstract ( 322 )   PDF (1906KB) ( 153 )   PURPOSE: To summarize the feasibility and advantages of C-shaped small incision for the treatment of benign lower posterior tumor of the parotid gland. METHODS: Forty-eight cases of benign lower posterior tumor of the parotid gland were treated with C-shaped small incision. The treatment outcomes were recorded and analyzed. RESULTS: The wound healed primarily in all 48 cases. The follow-up period was 1-5 years, and there was no recurrence of tumor and the shape of parotid region recovered well. The residual parotid tissue had certain secretory functions postoperatively. CONCLUSIONS: C-shaped small incision is an effective way of surgical treatment for lower posterior benign tumor of the parotid gland, which can reduce surgical trauma, shorten operation time, reduce facial scars, facial nerve injury, reduce tumor recurrence rate and preserve the function of the remaining parotid tissues. References | Related Articles | Metrics

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Comparative study of pain releasing effect of two approaches to acute pulpitis in the night emergency LIU Jian, SHI Cun-shan 2017, 26 (6):  669-671.  doi: 10.19439/j.sjos.2017.06.022 Abstract ( 851 )   PDF (2254KB) ( 265 )   PURPOSE: To compare the clinical effect of 2 methods for acute pulpitis in the night emergency. METHODS: Two hundred and twenty-three patients with acute pulpitis were randomly divided into experimental group (107 cases) and control group (109 cases). Patients in the experimental group was enclosed formaldehyde cresol (FC) with CAVITON-GC after removal of crown pulp, while patients in the control group was treated with open drainage. Pain releasing effect was evaluated and analyzed 2 days after treatment.The data were analysed by t test and χ2 test with SPSS19.0 software package. RESULTS: The average pain index of the experimental group was 1.23, which was lower than that of the control group (3.58), the difference was significant (P<0.05). The treatment efficiency was 93.46% in the experimental group, significantly higher than that in the control group (77.98% , P<0.05). CONCLUSIONS: Treatment in the experimental group is more effective to relieve pain than simple drainage in the control group. References | Related Articles | Metrics

Systemic Review

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Outcome of one-visit and multiple-visit root canal treatment for cracked tooth with pulpitis: a meta analysis WANG Wen, WANG Peng-lai, XIE Ni-na, WU Cui, LIU Zong-xiang 2017, 26 (6):  672-679.  doi: 10.19439/j.sjos.2017.06.023 Abstract ( 412 )   PDF (5957KB) ( 253 )   PURPOSE: To compare the treatment effect between one-visit and multiple-visit endodontic treatment for cracked tooth with pulpitis. METHODS: The literatures published before 2016-06-01 regarding to one-visit and multiple-visit root canal treatment for cracked tooth with pulpitis were searched through MEDLINE, CNKI, VIP, Wanfang Database et al. Then the included studies were chosen according to the inclusion criteria. Collection of features, quality evaluation and analysis of treatment effect, follow-up results (half year/1 year) and postoperative pain of the included studies were analyzed using Stata/SE12.1 software. RESULTS: A total of 24 Chinese literatures were included and no eligible foreign literatures were found. There were 3065 cases including 1608 with one-visit endodontic treatment and 1457 with multiple-visit endodontic treatment. Meta analysis showed that the effective rate (96.90%) and follow-up success rate (94.90%,94.60%) of one-visit endodontic treatment were significantly higher than multiple-visit one (84.00%,81.40%,89.00%),while there was no significant difference in postoperative pain [RR=0.96，95%CI (0.82，1.13)].The results did not change after sensitivity analysis. However，there were some differences in assignment methods and operations details among the literatures. CONCLUSIONS: The existing limited evidences show that one-visit endodontic treatment has higher effective rate than multiple-visit endodontic treatment and its postoperative pain is acceptable. However, more standard randomized controlled trials are needed. References | Related Articles | Metrics

Dental Education

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Case-based learning based on CBCT software in clinical teaching of oral and maxillofacial radiology ZHU Ling, CAO Xia, TAO Xiao-feng 2017, 26 (6):  680-683.  doi: 10.19439/j.sjos.2017.06.024 Abstract ( 277 )   PDF (2951KB) ( 158 )   PURPOSE: To compare the teaching result of case-based learning based on cone-beam CT (CBCT) software and traditional pantomography. METHODS: Thirty-eight interns (7-year programme) of grade 2011 from College of Stomatology, Shanghai Jiao Tong University were enrolled. The inner diameter of the nasopalatine ducts (A), the length of upper canine's pulp cavity (B), the length between root furcation of upper first molar and the maxillary sinus (C), the length between the root of lower wisdom tooth and the inferior alveolar nerve (D) were measured on pantomographic films and CBCT in the same case. The results of 38 interns were evaluated by Chi-square test with SPSS 16.0 software package. A questionnaire, given to the whole group of interns, was used to evaluate the teaching effect and the understanding of the 2D and 3D conception of the radiologic films. RESULTS: Only 3 data A, 14 data B, 10 data C, and 16 data D were measured on pantomography, respectively. Thirty-eight data A, 36 data B, 37 data C, and 38 data D were measured on CBCT. Significant difference was found between measurements on CBCT and pantomography in 4 groups (P<0.05). 38 interns finished the questionnaires survey. More than 95% interns delivered positive comments in inspiring interest, deepening knowledge, improving clinical thinking ability, and etc. CONCLUSIONS: Case-based learning based on CBCT software for measuring anatomic structures and building 3D concept can improve the quality in oral and maxillofacial radiology learning, deepen the understanding of the specialty, and increase efficacy of clinical teaching. References | Related Articles | Metrics

Review Article

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Features and influence of impacted maxillary permanent canine on surrounding structures LIU An-qi, QIAN Yu-fen 2017, 26 (6):  684-688.  doi: 10.19439/j.sjos.2017.06.025 Abstract ( 657 )   PDF (3766KB) ( 242 )   Impacted maxillary permanent canine is the tooth that most commonly fails to erupt after the third molars. It can probably affect the dental arch alignment and form, occlusal function and facial profile as well. In this review, the epidemiology, etiology and influence on surrounding tissue of the impacted maxillary permanent canine were analyzed based on related literatures with the hope of providing references for clinical practice. References | Related Articles | Metrics