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    25 March 2016, Volume 25 Issue 2 Previous Issue    Next Issue
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    Editorial
    The classification of malocclusions with facial prognathism and its clinical implications
    SHEN Gang
    2016, 25 (2):  129-135. 
    Abstract ( 511 )   HTML ( 33 )   PDF (2376KB) ( 613 )  
    Severe skeletal malocclusions with facial prognathism keep high prevalence in Chinese population. The classification and diagnosis of these malocclusions remain challenging due to the complicity and variety in their clinical manifestations, cephalometric morphologies and perceived etiologies. Based on elaborated studies about the extensive clinical archives and records, this article introduced an innovative classification of this specific anomaly, which not only provides with diagnostic specifics, but also indicates the possible etiologies and therapeutic guidance.
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    Original Articles
    The expression of VEGF-C in the condylar cartilage after anterior disc displacement and its clinical significance
    XU Gao-li,WANG Shu-hua,SHI Qiu-tao,LIU Yi,YAN Fan,XU Ting,GU Zhi-yuan
    2016, 25 (2):  136-140. 
    Abstract ( 189 )   HTML ( 0 )   PDF (973KB) ( 217 )  
    PURPOSE: To investigate the expression and significance of vascular endothelial growth factor-C in the condylar cartilage after anterior disc displacement of temporomandibular joint. METHODS: Sixty healthy adult Japanese rabbits were used in this study. Forty-eight rabbits were subjected to surgical anterior disc displacement in the right TMJs, every 12 rabbits were sacrificed 1, 2, 4, 8 weeks post-operation, 12 rabbits without operation were used as normal control.The gene expression and distribution of VEGF-C in condylar cartilage were studied by gene chip, real-time quantitative PCR and SP immunohistochemical methods. Paired t test was used for analysis with SPSS19.0 software package. RESULTS: After anterior disc displacement, the expression of VEGF-C in the 2nd week reached to a minimum level, there was a significant difference (P<0.05), and increased in the 8th week. VEGF-C was expressed by cells of articular cartilage in the proliferative zone, hypertrophic zone and calcified cartilage zone. The expression in 1-week group was mainly found in the deep proliferative zone and hypertrophic zone, while the expression mainly found in the hypertrophic zone in 2-and 4-week group; calcified cartilage gradually enhanced, and there was significant difference (P<0.05) between 8-week group and control group. CONCLUSIONS: VEGF-C gene transcription and expression may be involved in the remodeling of the condylar cartilage after anterior disc displacement.
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    Comparison of the shear bond strength by using nano silica sol to zirconia basement and veneer porcelain
    WANG Si-qian, ZHANG Da-feng, ZHEN Tie-li, YANG Jing-yuan, LIN Ting-ting, MA Jian-feng
    2016, 25 (2):  141-145. 
    Abstract ( 211 )   HTML ( 0 )   PDF (976KB) ( 316 )  
    PURPOSE: To investigate the feasibility of using sol gel technique to produce thin layer nano silicon dioxide on zirconia ceramic surface and the effect of improving shear bond strength between zirconia and veneer porcelain. METHODS: The presintered zirconia specimen was cut into a rectangle block piece (15 mm×10 mm×2.5 mm), a total of 40 pieces were obtained and divided into 4 groups, each group had 10 pieces. Four different treatments were used in each group respectively. Pieces in group A (control group) were only sintered at 1450℃ to crystallization; pieces in group B underwent 30% nano silica sol infiltration first and then were sintered at 1450℃ to crystallization; piece in group C underwent crystallization first at 1450℃, then 30% nano silica sol infiltration and were sintered at 1450℃ again; pieces in group D was coated by nano silica sol and then sintered at 1450℃ to crystallization; ten rectangle block pieces (12 mm×8 mm×2 mm) in group E were made. Cylinder veneers 5 mm in diameter and 4 mm in height were produced in each group and the shear bond strength was tested. Data were statistically analyzed by SPSS 19.0 software package. RESULTS: The shear bond strength of the 5 group specimens were: (28.12±2.95) MPa in group A, (31.09±3.94) MPa in group B, (25.60±2.45) MPa in group C, (31.75±4.90) MPa in group D, (28.67±3.95) MPa in group E, respectively. Significant differences existed between the 5 groups, and group C had significant difference compared with group B and D. CONCLUSIONS:① Use of nano silicon sol gel on presintered zirconia surface to make thin layer of nano silicon dioxide can improve the shear bond strength between zirconia and veneer; ②Using nano silicon sol gel on crystallization zirconia surface to make thin layer of nano silicon dioxide will decrease the shear bond strength between zirconia and veneer; ③ Zirconia veneer bilayer ceramic has the same shear bond strength with porcelain fused to Ni Cr alloy; ④Use of sol gel technique to produce thin layer nano silicon dioxide on zirconia ceramic surface is feasible and can improve shear bond strength between zirconia and veneer porcelain.
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    The effect of human PBMC on the growth of oral squamous cell carcinoma cell
    LIU Qi, SUN Zu-jun
    2016, 25 (2):  146-149. 
    Abstract ( 230 )   HTML ( 0 )   PDF (865KB) ( 225 )  
    PURPOSE: To explore the effect and mechanism of activated peripheral blood mononuclear cell (PBM) on the growth and apoptosis of oral squamous carcinoma cells in vitro. METHODS: ELISA, RT-PCR, MTT and flow cytometry were used to detect cytokines secretion and oral squamous carcinoma cell growth and apoptosis affected by activated PBMCs with PHA. The data was analyzed using SPSS17.0 software pakage. RESULTS: The cytokines secretion, mRNA expression of granzyme B and perforin, inhibition of growth and induction of apoptosis of oral squamous carcinoma cells treated by the activated PBMCs with PHA were significantly higher than the control groups (P<0.05). CONCLUSIONS: The human PBMC can be activated effectively with the stimulations of PHA, which can significantly inhibit growth and induce apoptosis of oral squamous carcinoma cells in vitro.
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    The effect of fluoride on electrochemical corrosion of the dental pure titanium before and after adhesion of Streptococcus mutans
    GENG Li, QIAO Guang-yan, GU Kai-kai
    2016, 25 (2):  150-156. 
    Abstract ( 184 )   HTML ( 0 )   PDF (1364KB) ( 233 )  
    PURPOSE: To investigate the effect of fluoride on electrochemical corrosion of the dental pure titanium before and after adhesion of Streptococcus mutans. METHODS: The dental pure titanium specimens were tested by electrochemical measurement system including electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PD) methods in artificial saliva with 0 g/L and 1.0 g/L sodium fluoride before and after dipped into culture medium with Streptococcus mutans for 24 h. The corrosion parameters, including the polarization resistance (Rct), corrosion potential (Ecorr), pitting breakdown potential (Eb), and the difference between Ecorr and Eb representing the “pseudo-passivation” (△E) obtained from the electrochemical tests were used to evaluate the corrosion resistance of dental pure titanium. The data were statistically analyzed by 2×2 factorial statistical analysis to examine the effect of sodium fluoride and adhesion of Streptococcus mutans using SPSS 12.0 software package. RESULTS: The results showed that the corrosion parameters including Rct, Ecorr, Eb, and △E of pure titanium had significant difference between before and after adhesion of Streptococcus mutans in the same solution(P<0.05), and in artificial saliva with 0 g/L and 1.0 g/L sodium fluoride(P<0.05). CONCLUSIONS: The dental pure titanium was prone to corrosion in artificial saliva with sodium fluoride. The corrosion resistance of pure titanium decreased distinctly after immersed in culture medium with Streptococcus mutans.
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    Temporal and spacial expression of LIM mineralization protein 1 during rat pulp injury and reparation
    FANG Ping-juan, PAN Yi-huai, SUN Ren-yi, ZHAO Yu , SUN Yu
    2016, 25 (2):  157-161. 
    Abstract ( 144 )   HTML ( 0 )   PDF (1630KB) ( 229 )  
    PURPOSE: To investigate the expression and localization of LIM mineralization protein 1(LMP-1) during rat pulp injury and reparation. METHODS: Dental pulp injury models were established in maxillary first molars on one side of 12 Wistar rats, the isonym healthy teeth on the opposite side were used as the controls. Immunohistochemistry technique was used to observe the expression of LMP-1 at 1, 3 and 7 day after pulp injury. The results of staining were analyzed by Image-Pro Plus 6.0 and SPSS 17.0 software package. RESULTS: LMP-1 was not detected in normal rat dental pulp. Positive staining of LMP-1 was found in odontoblasts and some dental pulp cells at 1 day after pulp injury. The expression of LMP-1 was converged at cell proliferation zone under the injury site at 3 and 7 day after injury. CONCLUSIONS: LMP-1 might play a role in the dental pulp cell proliferation and differentiation and reparative dentin formation during pulp injury and reparation.
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    Three dimensional finite element analysis of the influence of stress on occlusal surface of the mandibular first molar
    GAO Guo-ning, WANG Guo-you, SONG Ji-wu, LU Shou-yi
    2016, 25 (2):  162-171. 
    Abstract ( 237 )   HTML ( 2 )   PDF (1526KB) ( 245 )  
    PURPOSE: Use of three-dimensional finite element to analyze stress distribution and transient displacement of mandibular first molar both at the occlusal surface level, to investigate the biomechanical basis of vertical root fracture occurring in the mesial root. METHODS: Mimics finite element software was used to build the horizontal and tilt abrasion of the mandibular first permanent molar. Each status was then divided into 4 kinds of wearing degree and 8 models were then established including sliced 1, sliced 2, sliced 3, sliced 4 and miter 5°,miter10°,miter15°,miter20° respectively. 200 N of bite force was loaded on the occlusal surface using MSC. Marc nonlinear finite element analysis software was used to investigate the distribution of stress and transient displacement. RESULTS: When distal tipping angle of the abrasion plane of mandibular first molar increased from 5° to 15°, the angle between instant displacement contours and tooth long axis become smaller, the mesial root suffered from the biggest stress concentration and thus the possibility of longitudinal root fracture increased. CONCLUSIONS: When the abrasion plane of mandibular first molar tilted distally, the possibility of the mesial root longitudinal fracture increased.
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    Effect of topical iron, fluoride application on eroded enamel in vitro
    Yue,, CHONG Yan, HUANG Ruizhe
    2016, 25 (2):  168-171. 
    Abstract ( 197 )   HTML ( 0 )   PDF (1238KB) ( 212 )  
    PURPOSE: To evaluate the effect of supplementation containing iron and/or fluoride on eroded enamel in vitro. METHODS: Eighty enamel specimens collected in orthodontic treatments were randomly allocated into 4 groups of 20 samples each: C (control,deionized water); Fe2+ (15 mmol/L FeSO4); F- (1.23% NaF) and Fe2+ + F- (15 mmol/L FeSO4 and 1.23% NaF ). Before all samples submitted to 6 alternating demineralization and remineralization cycles, they were pre-treated with one of the experimental solutions for 1 minute. One complete cycle consisted of the following steps: ①demineralization in 5 mL beverage (Coca-Cola, pH=2.58) for 5 minutes under gentle agitation; ②remineralization in 5 mL artificial saliva for 1 hour at 37℃. The effect of erosion was observed by enamel surface morphology and measured by superficial micro-hardness (SMH). One-way ANOVA was performed using SPSS18.0 software package for analysis of the data. RESULTS: The SMH of enamel after erosion by carbonated drinks was significantly lower than the SMH before erosion. When ferrous sulfate with or without fluoride was tested for the prevention of enamel demineralization, there was statistically significant increase in the SMH of enamel in comparison with the control (P<0.001). However, the experimental solutions did not differ significantly among them. Scanning election microscope showed the deposition on the enamel surface after iron or fluorine treatment ,and the damage degree of the enamel surface were reduced compared with the control. CONCLUSIONS: Iron and/or fluoride was shown to be effective to enhance the acid resistance of enamel,while the combined use of fluoride and iron in group Fe2++F- had no cumulative effects.
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    The effect of carboxymethyl chitosan zinc and peptide on IL-1, TNF-α and PGE-2 in gingival crevicular fluid of miniature pigs
    LIU Xue-yu, PAN Ke-qing, ZHANG Li, DENG Jing, GUO Hun, SONG Jia, LIU Wan-shun, SONG Fu-lai
    2016, 25 (2):  172-176. 
    Abstract ( 172 )   HTML ( 0 )   PDF (819KB) ( 246 )  
    PURPOSE:This experiment was aimed at exploring whether carboxymethyl chitosan zinc and peptide (CMC-Zn+-P) can reduce the occurrence and development of periodontal tissue inflammation effectively by observing the change of IL-1,TNF-α and PGE-2 level in gingival crevicular fluid (GCF) before and after brushing, so as to find a new effective material in preventing and treating periodontal diseases. METHODS:Miniature pigs were selected as experimental subjects and divided into 4 groups randomly: the control group; CMC-Zn+-P group (material group);brushing group; brushing + CMC-Zn+-P group (composite group). Gingival crevicular fluid before and one month after the experiment was collected. The levels of IL-1, TNF-α and PGE-2 were examined by enzyme-linked immune-sorbent assay, while the clinical periodontal index was recorded. SPSS 18.0 software package was used for statistical analysis. RESULTS:There was no significant difference in levels of IL-1, TNF-α and PGE-2 and clinical periodontal index between the 4 groups before experiment. After one month, the levels of IL-1, TNF-α, PGE-2 in GCF had significant difference between 4 groups. The levels of IL-1, TNF-α, PGE-2 in composite group were significant lower than that of the other three groups (P<0.008).The levels of IL-1, TNF-αand PGE-2 in the material group and brushing group were significantly lower than that of the control group (P<0.008). Compared with materials group, the brushing group had significantly lower level of IL-1,significantly higher level of PGE-2 ,but no difference in the level of TNF-α.In addition, the teeth calculus index of composite group was significantly lower than that of other groups (P<0.05). CONCLUSIONS: CMC-Zn+-P can effectively reduce periodontal tissue inflammation and cut down the speed of deposition of dental calculus. If used cooperatively with brushing, the effect will be better.
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    The influence of different treating agents on the shear bond strength between zirconia and orthodontic brackets
    DONG Jun-chao, WEN Li-ming, LI Ren, LI Jin-yuan
    2016, 25 (2):  177-180. 
    Abstract ( 238 )   HTML ( 0 )   PDF (1101KB) ( 379 )  
    PURPOSE: To compare the effect of different treating agents on the shear bond strength (SBS) between zirconia and orthodontic brackets. METHODS: Fifty zirconia specimens were randomly divided into 5 groups(n=10), and treated with sandblasted and 37% phosphoric acid.Group A was control sample without any treatment; Group B was treated with silane coupling agent; Group C was treated with silane coupling agent and SE Bond; Group D were treated with Z-PrimeTM Plus; Group E were treated with Z-PrimeTM Plus+SE Bond. The upper incisor brackets were bonded to each specimen using 3M Transbond light-cured resin adhesive. Each specimen was put into 37℃ water, and SBS tests were performed after 24 hours. Then statistical analysis was carried out regarding to the adhesive residual index(ARI) of the zirconia oxide surface after removing the brackets. The surface of zirconia in each group was scanned with scanning electron microscope after surface treatment, and the surface morphology changes were observed, infrared spectra analysis was conducted on zirconia and treating agents. SPSS 17.0 software package was utilized for statistical analysis. RESULTS: The mean SBS in each group was as follows: group A (3.12±0.84) MPa; group B (1.92±0.83) MPa; group C (5.26±0.80) MPa; group D (6.54±0.98) MPa; group E (9.47±2.11) MPa. Significant difference existed between each group (P<0.05), group A and B had lower ARI, while ARI in group E was highest. Group D and E achieved effective bond strength. CONCLUSIONS: Using Z-PrimeTM Plus can achieve effective bond strength, which is lower than Z-PrimeTM Plus combined with SE Bond. It's suggested to use Z-PrimeTM Plus combined with SE Bond to achieve higher SBS for orthodontic treatment.
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    Precision validation of 3-D reconstruction of the craniofacial hard tissues based on 2-D digital radiograph
    FENG Yao-pu, ZHOU Hong, ZHAI Pei-fang, ZHANG Yan-ning, SUN Lin-lin
    2016, 25 (2):  181-186. 
    Abstract ( 154 )   HTML ( 0 )   PDF (1026KB) ( 280 )  
    PURPOSE: In this study, we validated the precision of 3-D craniofacial reconstruction of hard tissues based on 2-D digital cephalometric radiograph, in order to increase the level of orthognathic diagnosis and treatment, and promote communication between doctors and patients. METHODS: Deformation modeling based on 2-D digital radiograph and CT modeling was performed in 7 volunteers. 64 items were measured which described craniofacial hard tissue structure, intuitive overlapping and objective analysis were conducted. SPSS 17.0 software package was used for paired t test. RESULTS: 58 measurement items were not statistically different. Deformation modeling and CT modeling of the consistency was very high. CONCLUSIONS: Deformation modeling based on 2-D digital radiograph of craniofacial hard tissues is accurate and reliable, and basic deviation was within the allowed range. This 3-D reconstruction system could be used in clinic for diagnosis and operation simulation.
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    The role of Wnt5b in the promotion of osteogenic differentiation by puerarin
    ZHANG Zhi-ming, LUO Shan-feng
    2016, 25 (2):  187-190. 
    Abstract ( 202 )   HTML ( 0 )   PDF (888KB) ( 350 )  
    PURPOSE: To investigate the capability of puerarin on osteogenic induction in bone marrow-mesenchymal stem cells (BMMSCs), and to explore the mechanism of osteoinductivity of puerarin in vitro. METHODS: After segregating and cultivation, bone marrow stromal cells from 3-weeks SD rats were induced by osteogenesis medium containing different concentrations of puerarin in induction groups; while in non-induction group, BMMSCs were still cultured with DMEM medium. Following continued culture for 2-4 weeks, alkaline phosphatase activity, osteocalcin and Wnt5b were measured. The capability of puerarin on osteogenic induction of BMMSCs and the relationship between this effect and Wnt signaling pathway were investigated. SPSS 16.0 software package was used for statistical analysis. RESULTS: After induction with puerarin, the level of alkaline phosphatase activity, osteocalcin and Wnt5b increased.10-5 mol/L group showed the best effect. CONCLUSIONS: Puerarin can induce BMMSCs differentiation into osteoblasts. The mechanism may be related to Wnt signaling pathway.
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    Comparison of the shaping ability of three Ni-Ti rotary instruments in the preparation of simulated curved root canals
    QIU Ning, WANG Chu-yu, LIU Yu-fei, YU Xiao-qing, XUE Ming
    2016, 25 (2):  191-194. 
    Abstract ( 185 )   HTML ( 1 )   PDF (921KB) ( 317 )  
    PURPOSE: To compare the shaping ability of three rotary Ni-Ti instruments in simulated root canals. METHODS: A total of 30 simulated resin blocks were divided randomly into 3 groups: ProTaper Universal, ProTaper Next and TF Adaptive. Each group consisted of 10 root canals. The preparation time and changes in canal curvature were measured. Pre- and post-instrumentation photograghs were taken by precise camera and superimposed through Photoshop. The material removed from the inner and outer canal walls at 9 points beginning at 0 mm from the foramen were measured with Image Pro Plus. Centering ability was determined accordingly. The data was analyzed with SPSS13.0 software package. RESULTS: During root canal preparation, no instruments fractured. ProTaper Next was much faster than ProTaper Universal(P<0.05). At the apical curvature, transportation was the least with TF Adaptive, followed by Protaper Next (P<0.05). There were no significant differences in 3 groups with respect to coronal curvature transportation (P>0.05). CONCLUSIONS: Under the conditions of this study, ProTaper Next was the most efficient instrument. TF Adaptive and Protaper Next showed better shaping ability. In general, all the instruments respected original canal curvature well and were safe to be used.
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    The application of microvascular anastomotic device for free flap transfer in reconstruction of oral and maxillofacial defects
    SUN Qiang,, ZHAO Jun-fang, FANG Zheng, WANG Hai-bin, HAN Xin-guang, LI Xin-ming, SUN Ming-lei
    2016, 25 (2):  195-198. 
    Abstract ( 257 )   HTML ( 1 )  
    PURPOSE: To evaluate the clinical effect and summarize the experience of vein anastomosis by microvascular anastomotic device in reconstruction of oral and maxillofacial defects. METHODS: From September 2014 to May 2015, twenty-one free flaps were used to repair oral and maxillofacial defects. During surgery, facial artery or supra thyroid artery were selected as feeding arteries, and external jugular vein or the branch of jugular vein was used as the recipient vein. Eighteen arteries of the free flap were anastomosed by hand, 3 arteries and 21 veins were anastomosed by microvascular anastomotic device. The time of anastomosis and patency of vessels were recorded. Statistical analysis was performed using SPSS l7.0 software package. RESULTS: There was no flap necrosis due to venous thrombosis in this series.The facial artery was used as feeding artery 16 times, supra thyroid artery was used 5 times. The external jugular vein was used as reflux vein 13 times, the branch of jugular vein was used 8 times. The duration of artery anastomosis were 17.20±2.31 minutes by hand and 5.48±1.33 minutes by microvascular anastomotic device. The duration of vein anastomosis were 18.39±3.48 minutes by hand and 6.45±0.60 minutes by microvascular anastomotic device. CONCLUSIONS: Application of microvascular anastomotic device can significantly improve the anastomotic speed and vein flow rate. The preliminary results show that blood vessel anastomosis by device is effective and safe.
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    Clinico-pathological analysis of 45 parotid gland cysts
    WANG Zhi-ming, YE Ming,, YANG Dong-sheng, MA Ying, SU Xin, ZHANG Wei-qing, PAN Yao, GUAN Qiao-dan
    2016, 25 (2):  199-203. 
    Abstract ( 617 )   HTML ( 1 )   PDF (1368KB) ( 271 )  
    PURPOSE: To discuss the clinical and pathological characteristics and management of parotid gland cyst. METHODS: Forty-five resected samples of parotid gland tumors were selected from Shengjing Hospital of China Medical University from January 2000 to June 2014 whose postoperative pathological diagnosis were parotid gland cysts. The clinico-pathological characteristics in different types of parotid gland cysts were analyzed. RESULTS: Of 45 cases of parotid gland cyst, 25 were males, 20 were females. The median age was 51 years old. 21 cases were located on the left side of parotid gland, while 24 on the right side. The main clinical symptom was painless swelling in parotid gland region. The sizes varied from 0.8 cm×0.6 cm×0.5 cm to 10 cm×2.8 cm×0.6 cm. Nine cases were accompanied with pain, and 36 without. 4 cases were seen with lymph node enlargement, and 41 without pain. The main treatment modality was simple resection of cyst without any injury of facial nerve. No recurrence was seen after following up for 1-10 years. Of the 45 postoperative histopathological results, 29 cases (64.4%) were simple cysts, 9 cases (20.0%) were polycystic disease cysts, and 7 cases (15.6%) were lymphoepithelial cysts. Besides the above-stated pathological manifestations, some non-specific microscopic changes were accompanied with parotid gland cysts, including tumor-like hyperplasia of fibrous tissue, inflammations, calcifications, synovial cyst-like changes, foreign-body giant cell reactions and granulomatous changes. CONCLUSIONS: The main symptom of parotid gland cyst is progressive enlargement, and simple resection of cyst is the first-line treatment without facial nerve injury or reoccurrence. The main pathological classifications are simple cysts, lymphoepithelial cysts and polycystic disease cysts.
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    Clinical management of calcified root canal with Mtwo NiTi files
    ZHAO Jun-jun, ZHOU Zhuo-jun, HAN Jun-li, ZHU Ya-qin
    2016, 25 (2):  204-207. 
    Abstract ( 290 )   HTML ( 0 )   PDF (907KB) ( 430 )  
    PURPOSE: To evaluate the effect of Mtwo NiTi files in the management of calcified root canals. METHODS: Thirty-five calcified root canals from 21 cases unsuccessfully prepared with C-Pilot files and EDTA were treated with Mtwo NiTi files and EDTA. The data was analyzed with SAS 9.4 software package. RESULTS: Twenty-three calcified root canals were successfully prepared. The success rate was 65.71%. Instrument separation occurred in 4 root canals, and ledge occurred in 3 root canals. Categorized by calcified position, the success rate of three groups had no significant differences (P>0.05). CONCLUSION: Mtwo NiTi files can effectively process calcified root canals.
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    Radiographic study on the efficacy of mandibular advancement in patients with obstructive sleep apnea syndrome
    LI De-hong, YANG Xiang-hong, ZHOU Jing, ZHANG Ling-peng, SHU Wen
    2016, 25 (2):  208-211. 
    Abstract ( 305 )   HTML ( 0 )   PDF (946KB) ( 431 )  
    PURPOSE: To investigate the efficacy and mechanism of mandibular advancement device (MAD) treatment on obstructive sleep apnea syndrome (OSAS) patients. METHODS: Eighty OSAS patients treated with a mandibular protraction appliance were included in the study. Three-dimensional reconstruction technique was used as to measure the changes of upper airway structure and volume before and after MAD treatment. The data was analyzed using SPSS 17.0 software package. RESULTS: The anatomic structure and the reinforcement of soft tissue's collapse in the upper airway changed after application of MAD in OSAS patients; velopharyngeal and laryngopharynx configuration was significantly increased (P<0.01), while oropharyngeal configuration was significantly decreased (P<0.05). CONCLUSIONS: This study demonstrated that pathogeny of OSAS based on morphological characteristics may be removed by mandibular advancement device, the mechanism of efficacy of MAD treatment can be the reduction of airway internal fluctuation and vortex of air.
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    The effect of GDNF on matrix-degrading and cell-adhesion during perineural invasion of salivary adenoid cystic carcinoma
    ZHENG Shan-chuan, ZHANG Yu-ru, LUO Shu-yu
    2016, 25 (2):  212-216. 
    Abstract ( 162 )   HTML ( 0 )   PDF (1410KB) ( 259 )  
    PURPOSE: To investigate the possible contribution of GDNF in matrix-degrading, cell-adhesion during perineural invasion (PNI) of salivary adenoid cystic carcinoma (ACC). METHODS: Totally 42 ACCs and 5 normal salivary tissues were included in the present study.Immunohistochemical staining SP method was used to detect the expression of GDNF,MMP-9,NF-κB,integrin β1 in ACC specimens and normal salivary tissues. Statistical analysis was performed using SPSS16.0 software package. RESULTS:GDNF was strongly expressed in ACC tumor cells and nerve fibers adjacent to ACC tumor cells. NF-κB, MMP-9, integrin β1 were positively expressed in ACC cell cytoplasm, integrin β1 was also found in ACC cell membrane, and NF-κB in nuclei occasionally. The positive expression rate was 69.05%(29/42),66.67%(28/42),61.90%(26/42), respectively. The differences between the expression of NF-κB, MMP-9, integrinβ1 in PNI group and non-PNI group were significant (P=0.005,P=0.011,P=0.001, respectively). Expression of NF-κB, MMP-9, integrin β1 was correlated to that of GDNF(r=0.443, P=0.003; r=0.401, P=0.009; r=0.535, P=0.000, respectively). Expression of MMP-9 and integrin β1 was positively correlated to that of NF-κB(r=0.501, P=0.001; r=0.429, P=0.005). Expression of MMP-9 was correlated positively to that of integrin β1 (r=0.381, P=0.013). CONCLUSIONS:GDNF may increase the matrix-degrading and cell-adhesion of ACC in the process of PNI. NF-κB, MMP-9 and integrin β1 involve in ACC cells invading nerves.
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    Expression of differentiated embryo-chondrocyte expressed gene l in oral squamous cell carcinoma and its clinical significance
    YOU Jing-min, SU Tong, XIA Kun, LIN Lu, LIU qiong, ZHU Teng-fei
    2016, 25 (2):  217-220. 
    Abstract ( 252 )   HTML ( 1 )   PDF (1243KB) ( 268 )  
    PURPOSE: To investigate the expression of differentiated embryo-chondrocyte expressed gene l(DEC1)in oral squamous cell carcinoma(OSCC)and its clinical significance. METHODS: Detection of the protein expression of DEC1 in tissue specimens from 80 primary OSCC patients and 30 cases of normal oral mucosa were performed using immunohistochemistry. SPSS10.0 software package was uses for statistical analysis. RESULTS: The result of immunohistochemistry showed that positive expression rate of DEC1 in OSCC tissues was 92.50%, 5.00% in normal oral mucosa tissue. The difference was statistically significant (P<0.05). In OSCC tissues, the difference in expression of DEC1 was statistically significant (P<0.05) between highly differentiated group and lowly differentiated group, between patients with lymph node metastasis and patients without lymph node metastasis. CONCLUSIONS: The significantly increased DEC1 gene may be associated with the tumorigenesis and development of OSCC.
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    Cephalometric study of tongue crib combined with chincup treatment for anterior crossbite
    CAO Yu -ming,ZHANG Yuan-yuan, YU Mo, YUE Yang, LI Ang, TIAN Yu-lou
    2016, 25 (2):  221-226. 
    Abstract ( 409 )   HTML ( 1 )   PDF (1235KB) ( 523 )  
    PURPOSE: To evaluate the effect of anterior crossbite patients with bad tongue habit treated by tongue crib combined with chincup by cephalometric analysis. METHODS: A total of 25 patients (8 males, 17 females, age range 7~13 years, average age 8.6 years) of anterior crossbite with bad tongue habit or incorrect tongue position were selected. All cases used tongue crib combined with chincup therapy. Lateral cephalometric films taken at the beginning and the end of treatment were analyzed by Winceph 9.0 cephalometric software. All 19 measurement items were assessed by SPSS 17.0 software package. Following the consistency test, Mann-Whitney U test and Wilcoxon singed-rank test were carried out to compare the differences between pre- and post-treatment. RESULTS: All 25 cases obtained satisfactory results, the saggital relative position of maxilla and mandible was improved, anterior crossbite was corrected, occlusion was perfect and bad tongue habit and position were improved. Compared with pre-treatment, SNA, ANB, convexity were U1-SN, U1-NA, overjet and upper lip to E line increased significantly (P<0.05). SN-PP, SN-OP, L1-MP, L1-NB decreased significantly after treatment (P<0.05). The measurement items related to gender were analyzed separately. ANS-PNS and Cd-Gn increased in both male and female (P<0.05). CONCLUSIONS: Tongue crib can effectively correct bad tongue position, promote maxillary forward growth, and prevent the mandible from going ahead combined with chincup. It is an ideal interceptive orthodontic scheme for anterior crossbite with bad tongue habit.
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    Clinical evaluation of the prevalence of endodontic interappointment emergencies during intracanal medication before and after root canal preparation
    YANG Hong-li, TANG Rui, GONG Yu, ZHANG Yu-hao
    2016, 25 (2):  227-230. 
    Abstract ( 322 )   HTML ( 4 )   PDF (883KB) ( 302 )  
    PURPOSE: To evaluate the incidence of pain during intracanal medication before and after root canal instrumentation for therapeutic reference. METHODS: Three hundred and twenty four teeth were selected in this study, and the teeth received root canal therapy with crown-down technique using ProTaper rotary system, followed by calcium hydroxide intracanal medication. The degree of reported pain was recorded as 4 levels after treatment according to the Negm criteria. The incidence of endodontic interappointment emergencies (EIAE) at various recording times starting from root canal preparation was evaluated based on the results analyzed with MATLAB and SPSS19.0 software package. RESULTS: All patients reported of pain immediately after root canal therapy and calcium hydroxide intracanal medication, of which 1.54% were diagnosed as EIAE, the prevalence and degree of pain were increased. The prevalence of EIAE reached 25.62% one day after treatment, and decreased to 3.70% 3 days later. Most of the pain released without treatment; however, few patients experienced severe pain. The relationship between the EIAE percentage and time duration after treatment was fitted by using MATLAB as P(t)=100%×0.066t exp (t: hour; RMSE=3.91). The patient started to report free of pain 6 hours after the treatment, 33.64% of the patients were painless 1 week after treatment, and 82.71% were painless 2 weeks later. There was significant difference between the pain level before and 2 weeks after treatment (P<0.01). CONCLUSIONS: During root canal preparation and intracanal medication, the prevalence and degree of pain were increased immediately after treatment, decreased 3 days later, and most of the pain was released 2 weeks after treatment.
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    Casting Nance arch which allowed the upper canine's self-adjustment in the extraction cases
    QIN Fei, MA Xiao-qing, XU Pei-cheng, XIANG Fei
    2016, 25 (2):  231-234. 
    Abstract ( 132 )   HTML ( 0 )   PDF (1059KB) ( 285 )  
    PURPOSE: To study the upper canine's self-adjustment after the first premolar extraction and the effect of casting Nance arch in the sustainment of the upper first molar position. METHODS: Twenty severely crowded adolescents whose upper canines were in labial malposition were chosen. After the treatment plan was made, the upper first premolars were removed, the individually made casting Nance arches were fixed on the upper first molars. The measurement and fixed orthodontic treatment began 6 months later. Graphpad Prism 6.0 software was used for data analysis. RESULTS: The average movement of the malpositioned canines was (3.6±0.1)mm (P<0.01); while the forward movement of the first molars was (0.2±0.16)mm (P>0.05). CONCLUSIONS: Extraction of the first premolars is beneficial to the canine's self-adjustment in adolescents and the casting Nance arch could help keeping the first molar's positions.
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    Clinical effect of Class Ⅱ malocclusion treated with Forsus appliance following growth spurts
    ZHANG Zi-jin, TAO Lie
    2016, 25 (2):  235-237. 
    Abstract ( 318 )   HTML ( 0 )   PDF (823KB) ( 318 )  
    PURPOSE: To evaluate the clinical effect of Forsus appliance in the treatment of patients with Class Ⅱ malocclusion after growth spurts. METHODS: Twenty-two patients with Class Ⅱmalocclusion were treated with Fursus appliance.Cephalogram pre-and post-treatment was taken,and the clinical effect was evaluated.SPASS14.0 software package was used for paired t test. RESULTS: Six to eight months after treatment, SNB increased (1.4±0.002)°,overbite and overjet decreased (5±0.000) mm and (5.5±0.000) mm, the relationship of molar reached ClassⅠ, upper incisiors were retruded (1.5±0.004)°, while low incisiors were proclined (1.3±0.005)°. Significant difference was found before and after treatment (P<0.05). CONCLUSIONS: The growth of mandible was promoted remarkably by Forsus appliance following growth spurts, the relationship of molar and profile were also improved.
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    Comparison of root resorption between self-ligating and conventional brackets using cone-beam CT
    LIU Yun,GUO Hong-ming
    2016, 25 (2):  238-241. 
    Abstract ( 350 )   HTML ( 4 )   PDF (872KB) ( 1028 )  
    PURPOSE: To analyze the differences of root resorption between passive self-ligating and conventional brackets, and to determine the relationship between passive self-ligating brackets and root resorption. METHODS: Fifty patients were randomly divided into 2 groups using passive self-ligating brackets or conventional straight wire brackets (0.022 system), respectively. Cone-beam CT was taken before and after treatment. The amount of external apical root resorption of maxillary incisors was measured on CBCT images. Student's t test was performed to analyze the differences of root apical resorption between the 2 groups with SPSS17.0 software package. RESULTS: No significant difference(P> 0.05) in root resorption of maxillary incisors was found between passive self-ligating brackets and conventional brackets. CONCLUSIONS: Passive self-ligating brackets and conventional brackets can cause root resorption, but the difference was not significant. Passive self-ligating brackets do not induce more root resorption.
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    Clinical Reports
    Management of labially and mesially impacted canine by using modified vertical loop
    HE Wu-cheng, YAN Yu
    2016, 25 (2):  242-244. 
    Abstract ( 146 )   HTML ( 0 )   PDF (1071KB) ( 286 )  
    PURPOSE: To manage labially and mesially impacted canine by using modified vertical loop. METHODS: Five patients with unilateral labially and mesially impacted canine were included from the Department of Orthodontics, Xining First People's Hospital during 2011-2014 periods. All patients were treated by using modified vertical loop. RESULTS: The average duration of traction was 13.6 months. All impacted teeth were brought into the arch and obtained normal occlusion. CONCLUSIONS: It is an effective approach to manage the labially and mesially impacted canine by using modified vertical loop.
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    Application of residual crown of premolar restored with two shapes of fiber post systems
    LIU Jing-yu, RIZIWAGULI Amuti, HUANG Qing-feng
    2016, 25 (2):  245-247. 
    Abstract ( 261 )   HTML ( 0 )   PDF (784KB) ( 266 )  
    PURPOSE: To compare the effects of premolars restored with 2 different types of fiber post systems, so as to provide experience for restoration of residual crown of premolars. METHODS: Fifty-three residual crowns of premolar restored with fiber post systems were collected, and randomly divided into 2 groups: parallel fiber post group and double taper fiber post group. Repairing effect and operation difficulty were compared. The data was analyzed with SPSS 13.0 software package. RESULTS: There was no significant difference in success rate between the 2 groups, four complications occurred in parallel fiber post group and one in double taper fiber post group. CONCLUSIONS: The success rate between parallel fiber post groups and double taper fiber post group was not different, but the complication in double taper fiber post group is lower than parallel fiber post group.
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    Evidence-Based Dentistry
    Effectiveness of Nd:YAG laser with non-surgical periodontal therapy on improvement of periodontitis: meta analysis
    ZHAO Xi-da, LIU Jing-bo, ZHANG Chong, PAN Ya-ping
    2016, 25 (2):  248-253. 
    Abstract ( 332 )   HTML ( 2 )   PDF (911KB) ( 367 )  
    PURPOSE: The aim of the present meta analysis was to systemically evaluate the scientific evidence for the effectiveness of neodymium-doped yttrium aluminium garnet(Nd:YAG) laser in combination with non-surgical periodontal therapy compared to non-surgical periodontal therapy alone for patients with periodontitis. METHODS: Electronic database searches of MEDLINE-PubMed, ISI Web of Science, Cochrane Controlled Clinical Trial Register, Cochrane Database of Systematic Reviews, China National Knowledge Infrastructure(CNKI), Wanfang Data Knowledge Service Platform, CQVIP Company Profile, and China Biology Medicine disc were performed to identify appropriate studies for clinical randomized controlled trials, as well as hand-searching of relevant journals, conference paper and thesis of master and Ph. D from the earliest records to September 30, 2015. Quality assessment was made according to Newcastle-Ottawa Quality Assessment Scale(NOS), and the datum were extracted. Then heterogeneity test and meta analysis were performed on the outcomes, and the publication biases of the outcome by meta analysis were assessed. Meta analysis of interleukin-1β(IL-1β), gingival crevicular fluid(GCF), plaque index(PI), gingival index(GI), probing depth(PD) and attachment loss(AL) were performed using weighted mean differences for continuous data with 95% confidence intervals. RESULTS: A total of 12 articles met the eligibility criteria and entered into the study. When compared to non-surgical periodontal therapy alone, Nd:YAG laser in combination with non-surgical periodontal therapy showed significant differences in GCF(I2=0.0%,P=0.000), GI(I2=0.0%,P=0.000) and PD(I2=85.8%,P=0.032) at 12 weeks post-therapy. No significant publication biases were found. CONCLUSIONS: The findings of this meta analysis suggest that use of Nd:YAG laser as an adjunctive therapy to non-surgical periodontal therapy could potentially provide an effect at 12 weeks post-therapy. However, the evidence is insufficient that Nd:YAG could yield more AL gain than non-surgical periodontal therapy alone. Further research will focus on the operating standard and interval of Nd:YAG laser in periodontal therapy.
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    Case Reports
    Synovial chondromatosis of the right temporomandibular joint: report of one case
    FAN Rui-xian, ZHANG Kui-hong, DING Wei, WANG Yan-ling
    2016, 25 (2):  254-256. 
    Abstract ( 269 )   HTML ( 0 )   PDF (931KB) ( 347 )  
    Synovial chondromatosis of the temporomandibular joint(TMJ) is an extremely rare condition. A case of synovial chondromatosis with postoperative recurrence and involvement of base of skull was reported. The clinic pathological features, diagnosis and treatment were discussed with literature review
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