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20 October 2014, Volume 23 Issue 5 Previous Issue    Next Issue

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Basic Study

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Effect of TGF-β1 expression on periodontal tissue reconstruction for rapid teeth movement through reducing resistance and distraction LI Ning, YANG Le-le, PENG Zao-xia, LI Pei, LI Mei-jing, CHEN Xi, XU Ran 2014, 23 (5):  513-518.  Abstract ( 212 )   HTML ( 1 )   PDF (1549KB) ( 252 )   PURPOSE: To investigate the role of transforming growth factor-β1 (TGF-β1) in periodontal tissue reconstruction during rapid teeth movement through reducing resistance and distraction. METHODS: Twenty Beagle dogs were randomly divided into five groups according to time points: distraction for 5 days, 10 days, 15 days, retaining 10 days after distraction for 15 days, and retaining 90 days after distraction for 15 days. The mandibular first premolar was moved by using reducing resistance and distraction (experimental group) or conventional distraction (control group) randomly. For each group, tooth movement distance was measured and first premolar periodontal tissue pieces were obtained in scheduled time. Hematoxylin-eosin stain, Picric acid-Sirius red, and immunohistochemistry were performed. The data was analyzed by using SPSS 18.0 software package. RESULTS: The speed of tooth movement and periodontal reconstruction of the experimental group were significantly faster than the control group. TGF-β1 positive expression in two groups had similar distribution area, and reached peak at most active stage of osteogenesis in both groups. But in different stages of distraction, the positive expression in the experimental group was significantly higher than the control group(P<0.05). CONCLUSIONS: Compared with conventional orthodontic method, reducing resistance and distraction can obviously increase the expression of TGF-β1 of tension side of the distracted tooth, and accelerate periodontal tissue reconstruction. References | Related Articles | Metrics

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Effect of fluoride on the viability and apoptosis of ameloblasts in vitro MA Lin, ZHANG Ying, ZHONG Ming, ZHU Li, ZHANG Kai-qiang, GU He-feng, LIU Lu, ZHANG Si-yu, CHENG Rui-bo 2014, 23 (5):  519-523.  Abstract ( 193 )   HTML ( 0 )   PDF (985KB) ( 216 )   PURPOSE: To evaluate the effect of fluoride on viability of rat ameloblasts in vitro. METHODS: The ameloblasts of rat was exposed to different concentrations of NaF (0, 0.4, 0.8, 1.6, 3.2, 6.4 mmol/L) for 24, 48 and 72 hours. CCK-8 assays were performed to measure the cells proliferation; The morphology of apoptosis was observed by Hoechst 33258 staining and the rate of apoptosis was determined by flow cytometry. The data was analyzed using SPSS 13.0 software package. RESULTS: ①The proliferation of ameloblasts was increased when concentrations of NaF between 0.4 mmol/L and 0.8 mmol/L, whereas inhibited at 1.6 mmol/L NaF and above. The effects were in time-dependent manner.②Cells in the 1.6 mmol/L NaF groups showed unclear karyorrhexis and apoptotic cell morphology. The effects were in concentration-dependent manner. CONCLUSIONS: ① Fluoride has two-phase effects to ameloblasts: At low doses, it promoted cell proliferation while at high doses it had negative effects. ②1.6 mmol/L NaF could induce apoptosis of ameloblasts. References | Related Articles | Metrics

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The effects of ADAM28 AS-ODN on biological function of human gingival fibroblasts ZHAO Zheng, WEI Li, Li Lu-jia, YE Yong, HUANG Zheng-nan, YANG Hai-qing 2014, 23 (5):  524-530.  Abstract ( 137 )   HTML ( 0 )   PDF (1194KB) ( 212 )   PURPOSE: To study the effects of a disintegrin and metalloproteinase 28 (ADAM28) antisense oligodeoxynucleotide (AS-ODN) on proliferation, differentiation and apoptosis of human gingival fibroblasts (HGFs), and analyze the possible mechanism. METHODS: Cell culture, gene transfection, MTT chromatometry, enzyme dynamics, and flow cytometry (FCM) techniques were used to detect the effects of ADAM28 AS-ODN on biological characteristics of HGFs after transfected into HGFs. The statistical differences were evaluated by SNK test with SPSS 16.0 software package. RESULTS: In ADAM28 AS-ODN group, the proliferation activity of HGFs decreased significantly. Cell percentage in S phase in AS-ODN group was notably lower than that of S-ODN and untransfected groups, and cell percentage in G2+M phase was remarkably lower than that of untransfected group. Cell proliferation index（PI=S+G2M）in AS-ODN group was significantly lower than that of the other two groups. There was a significant difference between the groups. In AS-ODN group, alkaline phosphatase (ALP) secretion activity and percentage of apoptotic cell notably increased. CONCLUSIONS: ADAM28 AS-ODN could inhibit HGFs proliferation significantly and influence the changes of cell cycle, promote HGFs differentiation and induce HGFs apoptosis remarkably. References | Related Articles | Metrics

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Effect of CORM-2 on atherosclerosis in experimental periodontitis of rats HOU Meng, WANG Ping, ZHAO Li, LI Ying, ZHAO Hua-qiang, SONG Hui 2014, 23 (5):  531-538.  Abstract ( 205 )   HTML ( 1 )   PDF (2112KB) ( 209 )   PURPOSE: To evaluate the effect of CORM-2 (carbon monoxide releasing molecule-2) on atherosclerosis in experimental periodontitis of rats. METHODS: Forty Wistar rats were divided into four groups randomly. Rats in control group did not receive any procedure; animals in the carbon monoxide group (CO group) and the chronic periodontitis group (CP group) were induced experimental periodontitis and treated with CORM-2 (10mg/kg per day), or normal saline solution (NaCl 0.9%), respectively; animals in the solvent group (DMSO group) received dimethylsulfoxide solution (DMSO 0.05%) only. Blood samples were collected after 1, 3, 7, 14 and 28 days from all animals for analysis of C react protein (CRP), oxidized low density lipoprotein (ox-LDL), soluble vascular cell adhesion molecule-1, (sVCAM-1) and interleukin-10 (IL-10) by enzyme-linked immunosorbent assay (ELISA). Rats were sacrificed after 28 days. Lipid deposition was checked by means of oil red staining in the descending aorta. Changes in alveolar bone levels were measured and periodontal tissues were histopathologically examined to assess the infiltration of inflammatory cells. SPSS17.0 software package was used to analyse the experimental data. RESULTS: The serum levels of CRP, ox-LDL and sVCAM-1 in CP group were significantly higher than that in CO and the other two groups (P<0.05). The level of IL-10 in CP group was significantly lower (P<0.05). Lipid deposition in the descending aorta was observed in CP group. The alveolar bone loss and the ratio of presence of inflammatory cell infiltration (ICI) in CP group were significantly higher compared with CO groups (P<0.05). CONCLUSIONS: This study demonstrated that CORM-2 can not only reduce the inflammatory response in periodontal tissues in rats with experimental periodontitis, but also inhibit atherosclerosis-associated cytokines and lipid deposition in descending aorta, which suggests a favorable potential in treatment of periodontitis and atherosclerosis. References | Related Articles | Metrics

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Experiment study on the repair of rabbit skull defect with HAP-GEL scaffolds combined with cultured osteoblasts GENG Hai-xia, GUO Xiu-juan, QIAN Jun-rong, FENG Wei 2014, 23 (5):  539-542.  Abstract ( 230 )   HTML ( 3 )   PDF (1313KB) ( 229 )   PURPOSE: To investigate the ability of composite graft of osteobalsts and HAP-GEL scaffolds to repair cranial bone defect. METHODS: HAP-GEL and osteoblasts were co-cultured.The rabbit cranial parietal bone defect models were established. HAP-GEL scaffolds and osteoblasts were implanted into the cranial bone defects with blank defect as negative control, autologous skull as positive control. After 4,8,12 weeks, the result was evaluated by gross inspection, three-dimensional computed tomographic scanning and histological examination, respectively. RESULTS: After 4, 8, 12 weeks, blank defects displayed significantly radiolucent area, HAP-GEL with osteoblasts and autologous skull restoration showed high density area, the edges were slightly blur. With time going by, part of the scaffolds were absorbed, and the new bone trabecula was observed in histological examination. In the control groups, only fibrous tissues were observed in the defect region, there was no new bone formation. CONCLUSIONS: The engineering bone constructed by osteoblasts and HAP-GEL scaffold can be applied to repair bone defect. References | Related Articles | Metrics

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Electrochemical impedance spectroscopic study of titanium in physiological environment with blood-serum protein LV Ji-xin, WENG Wei-min 2014, 23 (5):  543-546.  Abstract ( 170 )   HTML ( 0 )   PDF (622KB) ( 225 )   PURPOSE: Electrochemical impedance spectroscopy (EIS) was employed to study the corrosion behaviour of titanium in dummy environment with blood-serum protein. METHODS: EIS of titanium in PBS and cell culture fluid was acquired by advanced electrochemical system. The characteristic of EIS-Nyquist and EIS-Bode were investigated and the equivalent circuit was used to analyze the EIS results. The data was analyzed using SPSS 11.0 software package. RESULTS: The corrosion resistance of the titanium in cell culture fluid was significantly higher than that in PBS (P<0.05). The phase angle of TiO2-based passive film at low frequency decreased to 55° when titanium was in PBS, but 75° when in cell culture fluid. CONCLUSIONS: The blood-serum protein plays an important role in the corrosion behaviour of titanium in physiological environment. References | Related Articles | Metrics

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Coculture of stem cells from the apical papilla and human umbilical vein endothelial cells enhances the angiogenic potential of dental pulp tissues YUAN Chang-yong, WANG Peng-lai, ZHANG Cheng-fei, LIU Zong-xiang, LUO San-lian 2014, 23 (5):  547-552.  Abstract ( 176 )   HTML ( 0 )   PDF (1619KB) ( 212 )   PURPOSE: To observe the effect of coculture of stem cells from the apical papilla (SCAPs) and human umbilical vein endothelial cells (HUVECs) on the angiogenic potential of dental pulp tissues. METHODS: SCAPs were incubated in osteo/odontogenic, adipogenic, neurogenic induction medium and α-MEM medium, whose multilineage differentiation capacities were confirmed using alizarin red staining, oil red O staining and βⅢ-tubulin immunofluorescent staining. The tubular length, branching points number and junctional areas were detected after 3, 6, 9 h since cells were seeded onto matrigel, and the data was analyzed using SPSS 16.0 software package. RESULTS: SCAPs in the experimental groups were detected having more lipid droplets, mineralization nodules and neuron-like cells. Coculture of SCAPs and HUVECs formed more vessel-like structures in tubular formation assay. CONCLUSIONS: SCAPs are capable of differentiating into fat, bone, and nerve-like cells in vitro. Coculture of SCAPs and HUVECs can enhance the angiogenic potential of dental pulp tissues. References | Related Articles | Metrics

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Study of relationship between different contents of zinc and antibacterial activity on calcium phosphate coating modified by plasma electrolytic oxidation method WANG Dan-ning, JIANG Lu-lu, ZHANG Wei, HE Jing, SHANG Ya-wei, ZHAO Bao-hong 2014, 23 (5):  553-560.  Abstract ( 165 )   HTML ( 0 )   PDF (2531KB) ( 171 )   PURPOSE: Calcium phosphate activity coating containing different contents of zinc was deposited onto the surface of pure titanium modified by plasma electrolytic oxidation. The physical and chemical properties of different contents of zinc were compared among three groups, and the influence on antibacterial activity of P.gingivalis (Pg) and A.actinomycetemcomitans (Aa) was evaluated. METHODS: Pure titanium samples were treated in the electrolyte of plasma electrolytic oxidation with 0.08 mol/L calcium and 0.06 mol/L phosphorus, and 0.01, 0.03, 0.05 zinc was added to each group in order to deal with pure titanium plate. Titanium samples were divided into three groups: low, middle and high group according to zinc contents. The group without zinc was as control. The binding force of coating and titanium was tested by electric universal test machine. The topography of surfaces was observed under scanning electron microscope (SEM). The crystalline structure of surfaces was determined by XRD. The chemistry and elements of surfaces were determined by XPS. Pg and Aa were seeded onto samples surfaces, and the antibacterial properties of four kinds of materials were evaluated by using scanning electron microscopy and the paster method. Statistical analysis was performed using SPSS 13.0 software package. RESULTS: It was found that the aperture and roughness were increased with the increase of content of zinc. The crystallization of low zinc group was superior to high zinc group. The content of HA and Zn3P2 in low zinc group was more, but ZnO in high zinc group was more. Scanning electron microscope demonstrated that the number of Pg and Aa decreased on the surface with the increase of the content of zinc, while the bacteria of high zinc group underwent lysis and necrosis. By using the paster method, the number of Pg and Aa decreased on the surface with the increase of the content of zinc, and there was significant difference among the four groups. CONCLUSIONS: The change of zinc content will change the physical and chemical properties of the coating; at the same time, the antimicrobial property of calcium phosphate coating with high content zinc was the best. References | Related Articles | Metrics

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Experimental evaluation of pure traditional Chinese medical mouth rinse on skin and mucosa stimulation and bacteriostatic-bactericidal effect MA Mu-zhi, LIU Zhao-jun, LU Jia-tong, CHEN Gong-pei, YU Fei, ZHENG Yuan-na 2014, 23 (5):  561-565.  Abstract ( 591 )   HTML ( 4 )   PDF (1119KB) ( 932 )   PURPOSE: To observe the stimulating effect of pure traditional Chinese medical mouth rinse (PTCMMR) on skin and mucosa and to evaluate the efficacy of PTCMMR on inhibiting and killing oral common bacteria. METHODS: PTCMMR and normal saline (NS) were separately dripped onto 14 five-month rabbits' left and right eyes for 7 days, and were smeared on the left and right side of buttocks, abdomens, back of 10 seven-month guinea pigs (after hair removal) once a day for comparison between the two sides. Five animals were sacrificed after 3 and 7 days of smearing to make pathological sections. Bacterium suspension with Staphylococcus aureus, Escherichia coli, Candida albicans, Pseudomonas aeruginosa and Streptococcus B were dropped to nutrient solution containing different concentrations of PTCMMR or compound Borax solution to observe the growth situation of bacteria. Inhibition zone diameters were measured after 18h of incubation within 37℃ incubator. The data was statistically analyzed using SPSS 17.0 software package. RESULTS: There was no obvious change such as redness, dermatitis between rabbits’ left eye conjunctiva and the control group. The bacteriostatic and bactericidal effect of anaerobe and aerobe with dropping of PTCMMR was stronger than that of control group. CONCLUSIONS: PTCMMR has no stimulation to skin and mucosa, while it has strong efficacy to inhibit and kill oral common bacteria. References | Related Articles | Metrics

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A study on the development of TMPT-contained trial dentin sealant ZHOU Qin, LIN Tong, TAN Wen-hong, XIAO Min, LU Yi 2014, 23 (5):  566-570.  Abstract ( 208 )   HTML ( 0 )   PDF (644KB) ( 201 )   PURPOSE: To investigate the effect of resin curing system formulations of TMPT-contained trial dentin sealant on its bonding and polymerization properties. METHODS: Commercially available Hybrid Coat (HyC) and previously trial TMPT-contained dentin sealant T33 as control groups, adjusting camphorquinone (CQ) content to make CQ trial dentin sealants. Their dentin shear bond strength was tested to find the strongest group named CQn as the next test substrate. N-phenylglycine (NPG) content of original sponges was adjusted to make NC trial sponges. Bond strength and degree of conversion of CQn were tested using each NC trial sponges. The data was analyzed by SPSS13.0 software package. RESULTS：CQ3 showed the biggest bond strength in the group of CQ trial sealants of about 12.99 MPa. When CQ3 was used with every NPG trial sponges, NPG4.4 and NPG7.3 groups showed the statistically greatest bond strength of about 14.68 and 14.69 MPa (P<0.05). And NPG7.3 also showed the maximum degree of conversion of about 83.2%. CONCLUSIONS: The bonding strength and degree of conversion of trial TMPT-contained dentin sealant were the biggest when molar ratio of CQ and NPG was 1:4.4 or 7.3, but the material properties need to be tested in subsequent experiments. References | Related Articles | Metrics

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Effects of 5-aza-2-deoxycytidine on methylation status of RECK gene and cancer cell invasion in tongue cancer SCC-4 cells JIANG Xv 2014, 23 (5):  571-574.  Abstract ( 243 )   HTML ( 0 )   PDF (538KB) ( 224 )   PURPOSE: To investigate the effects of 5-aza-2-deoxycytidine on methylation status and invasion ability of RECK gene in tongue cancer SCC-4 cells. METHODS: Tongue cancer cell line SCC-4 cells were treated with 5-aza-dC at different concentrations for 72 h. Methylation status of RECK gene of SCC-4 cells was detected by methylation specific PCR (MSP), the expression of RECK gene mRNA was detected by real-time quantitative PCR. The expression of RECK protein was detected by Western blot, and the invasion ability of SCC-4 cell was examined by Transwell assay. SPSS13.0 software package was used for statistical analysis. RESULTS: RECK gene of SCC-4 cells was in high methylation status in untreated group, abnormal methylation was effectively reversed by 5-aza-dC treatment. After treatment with different concentration of 5-aza-dC for 72 h, relative mRNA expression level increased gradually (P<0.05). The relative expression level of RECK protein in 5-aza-dC treated group was significantly higher than that in the control group,the invasion ability of SCC-4 cell was decreased gradually. CONCLUSIONS: 5-aza-dC treatment for tongue cancer SCC-4 cells can successfully reverse high methylation status of RECK gene and restore the expression of RECK gene mRNA and protein, and reduced the invasion ability. References | Related Articles | Metrics

Clinical Study

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Correlation analysis of EphA7 expression with clinico-pathological parameters and prognosis in tongue squamous cell carcinoma LI Dan, XIANG Bing, YING Xiao-xia, DONG Hui 2014, 23 (5):  575-579.  Abstract ( 273 )   HTML ( 0 )   PDF (1172KB) ( 223 )   PURPOSE: To evaluate the relationship between the expression of EphA7 and its clinical correlation and function with tongue squamous cell carcinoma (TSCC). METHODS: The expression of EphA7 was determined in 54 pairs of human TSCC tissues and pair-matched adjacent noncancerous tissues by immunohistochemistry. Furthermore, association between EphA7 expression and patients’ clinicopathological characteristics, overall and disease-free survival were evaluated. Invasion and metastasis of SCC9 cell were detected before and after down regulation of EphA7 expression. Differences in measurement data were compared with paired-t test, and survival analysis was made by Kaplan-Meier method using SPSS17.0 software package. RESULTS: EphA7 was positive in all examined specimens. Significant associations were noted between high EphA7 expression and absence of lymph node metastasis, absence of vascular invasion, dense stromal inflammatory reaction and female gender. TSCC patients with higher EphA7 expression presented longer overall and disease-free survival compared with low EphA7 expression. The invasion and metastasis of SCC9 cell increased significantly after down regulation of EphA7. CONCLUSIONS: The study indicated that EphA7 may participate in the malignant transformation of TSCC, reinforcing their utility as targets for potential therapeutic intervention. References | Related Articles | Metrics

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Clinical effect of functional repair of bilateral cleft lip in 66 patients LI Ming, JIANG Hong-bing, YUAN Hua, DU Yi-fei, WU Yu-nong, WAN Lin-zhong 2014, 23 (5):  580-585.  Abstract ( 172 )   HTML ( 0 )   PDF (1370KB) ( 242 )   PURPOSE: To explore the clinical effect of functional repair for bilateral cleft lip using modified Mulliken method. METHODS: Sixty-six patients with bilateral cleft lip were selected and assigned to receive modified Mulliken method. During the operation, the prolabium was kept as narrow "tie" shape, the orbicularis oris was anatomically repositioned, and the orbicularis oris ring was re-built. Vermilion tubercle was reconstructed with the lateral red vermillion. The nasal deformity was preliminarily repaired. and the nasal columella was elongated at the same time. RESULTS: All the patients were followed-up for 0.5-2 years, there was no “trisection upper lip”. The symmetry and natural shape of Cupid’s bow were obtained in more than 80% patients. The width of philtrum was similar to normal children. Full vermilion of the lips, moderate-size vermilion tubercles and good dynamic and static shape were obtained without whistle deformities. Normal width of nasal base and nostril symmetry were gained. The columella was elongated. Satisfactory contour of the nasal tip was achieved. CONCLUSIONS: Modified Mulliken method could functionally repair bilateral cleft lip and effectively correct nasolabial deformities. It is worthy of wide clinical application. References | Related Articles | Metrics

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Evaluation of facial aesthetics in young population with beautiful faces in Nanchang city QU Jing, LU Xing, GE Hong-shan, LIU Wei-jia, ZHI Qiang, WANG Di-kan 2014, 23 (5):  586-589.  Abstract ( 255 )   HTML ( 0 )   PDF (438KB) ( 279 )   PURPOSE: To analyze the full-face and lateral aesthetical standards among fine looking young people in Jiangxi province, in order to provide reference for orthodontic treatment. METHODS: Fourteen young males and fifteen young females from universities in Nanchang city were selected through audition of young beauty within Jiangxi province. Their full-face and lateral pictures were then taken. Ten orthodontists and 85 non-orthodontists in different ages and sexuality who were randomly selected were asked to rank all of the selected pictures in descending order of attractiveness independently and also pick out the most beautiful male and female photos according to their own judgments. Comparisons were carried out to select the universally recognized beautiful males and females and analyze their soft tissue facial profile. RESULTS: Orthodontists held significantly different opinions on the facial esthetic profile for males and females, especially for males. On the other hand, although the non-professionals also had different views on the profiles, the evaluations for males were quite consistent. To be specific, young people selected No.13 male and No.1 female while the old people preferred to select No.7 male and the No.9 female. At the same time, men selected No.7 and No.13 male, and No.1 and No.9 female while women selected No.13 male and No.1 female. CONCLUSIONS: Both orthodontists and non-orthodontists have different opinions on the facial esthetic profile for young males and females. During orthodontic treatments, orthodontists should respect the opinions of the patients and their family members on the matter of facial improvements. References | Related Articles | Metrics

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Study on articulation characteristics of patients after cleft palate repair in Henan province HUANG Ying-ying, LI Xin-ming, ZHAO Jun-fang, LI Feng 2014, 23 (5):  590-592.  Abstract ( 209 )   HTML ( 1 )   PDF (403KB) ( 249 )   PURPOSE: To establish the pathological speech characteristic of patients after cleft plate repair in Henan province by unusual speech frequency and vowel formants. METHODS: One hundred normal speech patients and 121 patients after cleft palate repair were selected, their formant frequency of vowels/ a,o,e,i,u,ü/ were obtained. The pathological speech frequency was collected in 121 postoperative patients. The acoustic features of the vowel were compared by SPSS17.0 software package with two independent sample t test. RESULTS: According to articulation position, 21.9% of misarticulation of postoperative patients occurred in dental consonants, 5.2% in retroflex consonants, 21.6% in alveolar consonants, 19.2% in palatal consonants, 12.9% in velar consonants and 6.6% in dorsum consonants. The average value of F2 of/a, o, e, u/did not show significant difference between the two groups (P>0.05).The difference of average value of F2 of /i,ü/ was significant (P<0.05). The average value of F1 of/a, o, e, I, u/did not show significant difference between the two groups (P>0.05).Except /a/,the average value of F3 of vowel /o, e, i, u, ü/showed significant difference between the two groups (P<0.05). CONCLUSIONS: Misarticulation of patients after cleft palate repair in Henan province mainly occurred in dental consonants, alveolar consonants and palatal consonants; tongue over curly can be observed in operated patients with cleft palate. There was no significant difference between the two groups in mouth opening. References | Related Articles | Metrics

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An analysis of soft tissue profile features of beautiful men and women with polar coordinates WANG Shi-xing, ZHAO Jun-jie, FENG Yan, LIU Zong-xiang 2014, 23 (5):  593-596.  Abstract ( 155 )   HTML ( 1 )   PDF (463KB) ( 241 )   PURPOSE: To analyze the profile features of soft tissues of beautiful young men and women with Han nationality by polar coordinates. METHODS: Sixty-two beautiful college students (aged 18-23 years, average 20.1 years, 31 men, 31 women) were chosen according to inclusion criteria as study samples. The lateral cephalograms of the samples were taken in natural head position. The polar system was established with the Bolton (Bo) point as the pole, and the Bo-N line as the polar axis. The polar coordinates were measured of the mark points on the soft tissues of the samples’ maxillofacial regions respectively. The measured data were statistically analyzed with SPSS 17.0 software package. RESULTS: There were no significant differences among the polar angles of the marking points on the soft tissues (P>0.05), the results were not statistically significant; there were significant differences among the measured data of line distances (P<0.01); the ratios of the polar radius of each mark point and Bo-N were not significantly different (P>0.05); there were significant differences among the values of Bo-Pos/ Bo- Sn, Bo- LL/Bo-Pos between men and women, which was statistically significant (P<0.05). CONCLUSIONS: Polar coordinates can be applied to cephalometry to accurately and integrally describe maxillofacial profile features. There are minor differences between the profile features of beautiful men and women, and the differences are mainly shown in mandible and the fullness of lips. References | Related Articles | Metrics

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Efficacy evaluation of fixed Twin-block appliance and tooth extraction in skeletal Class Ⅱ malocclusion GONG Yao, YU Quan, LI Pei-lun, WANG Hong-hong, WEI Bin, SHEN Gang 2014, 23 (5):  597-600.  Abstract ( 311 )   HTML ( 1 )   PDF (465KB) ( 276 )   PURPOSE: To evaluate the skeletal and dentoalveolar effects of Twin-Block combined with straight wire appliances and tooth extraction in the treatment of skeletal Class Ⅱ malocclusion with mandibular retrognathia in growing individuals. METHODS: The sample comprised 31 growing individuals with skeletal Class Ⅱ and mandibular retrognathia,divided into 2 groups. One group (18 patients) was treated with fixed Twin-block combined with fixed appliance; the other group (13 patients) was only treated with fixed appliance after tooth extraction. Lateral cephalograms pretreatment and posttreatment were taken before and after Twin-block treatment and after all fixed appliance treatment. Pancherz’s cephalometric measurements were analyzed statistically. Intragroup and intergroup changes of the two groups were evaluated by test using SPSS 15.0 software package. RESULTS: According to Pancherz's analysis, mandibular length increased, point Pg, mandibular incisors and first molars moved forward, maxillary incisors moved backward, overjet decreased (P<0.05) after treatment with Twin-block and fixed appliance. Within the rectification of anterior overjet, proportion of dentofacial factor was 39.5%, skeletal factor was 60.5%. Within the rectification of posterior relationship, proportion of dentofacial factor was 44.9%, skeletal factor was 55.1%. CONCLUSIONS: Twin-block combined with fixed appliance treatment can efficiently promote mandibular growth, restrict forward growth of maxilla to some extent, correct incisor and molar relationship and improve skeletal profile in growing skeletal Class Ⅱ individuals with mandibular retrognathia. References | Related Articles | Metrics

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Study of the root canal characteristics of mandibular central incisors in 150 patients using cone-beam computed tomography ZHANG Lu-dong, WANG Hai-ning, ZHU Ya-qin 2014, 23 (5):  601-604.  Abstract ( 389 )   HTML ( 0 )   PDF (502KB) ( 200 )   PURPOSE: To investigate the root canal characteristics of mandibular central incisors using a cone-beam computed tomography (CBCT) technique. METHODS: One hundred and fifty patients (79 males and 71 females) receiving CBCT scan at Shanghai Ninth People’s Hospital were recruited into this study. A total of 295 image samples of mandibular central incisors were obtained and analyzed in terms of the number and type of root canals. RESULTS: The majority of mandibular central incisors had a single canal (61% possessed a Type I canal system). Although 39% of the roots possessed two canals, only 8.8% had two separate apical foramina. CONCLUSIONS: The prevalence of two canals of mandibular central incisors in this case series was 39% and is within the range reported by previous studies on case series of different racial origin. References | Related Articles | Metrics

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Oral candida species distribution in patients receiving radiotherapy for head and neck cancer ZHANG Yuan-yuan, LI Ai-qin, WANG Ning-ning, LIU Li-na, CUI Ji-li 2014, 23 (5):  605-608.  Abstract ( 255 )   HTML ( 1 )   PDF (501KB) ( 234 )   PURPOSE: To investigate the distribution of oral candida species in head and neck cancer (HNC) patients treated with radiation therapy, and provide the basis for planning of clinical preventive measures. METHODS: Saliva was sampled from 60 HNC patients before, during and after radiation. Concomitantly, 60 healthy individuals whose age and sex matched that of the patient group were selected as control group. Oral candida carriages were quantitatively detected and the different candida species were identified by multiple measures such as CHROMagar candida culture medium and API 20C AUX yeast identification system. Then the differences between the two groups in terms of the candida detection rate and the distribution of each species of candida were analyzed with SPSS 17.0 software package. RESULTS: Xerostomia and dysphagia was found in 54 HNC patients during radiotherapy, radiation-induced oral mucotitis(RIOM) was found in 50 HNC patients,and oral candidiasis was found in 18 HNC patients; In radiation group, the detection rate of candida colonization during radiation was 56.7%, 63.3% postradiation, which showed significant differences compared with pre-radiation (χ2=18.320,P<0.001 ); Among the 54 identified clinical isolates, candida albicans (n=42) was the most frequent, followed by candida parapsilosis (n=6), candida tropicalis (n=4) and candida glabrata (n=2). In radiation group, the oral candida pathogens detection rate was 30%, and candida colonization was 46.7%. CONCLUSIONS: The oral candida colonization rate was significantly higher in HNC patients after radiotherapy, which indicated that the candida infection may be closely related to RIOM. References | Related Articles | Metrics

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Correlation between anxiety, depression and pefectionistic tendencies in patients before orthodontic treatment LUO Heng, FENG Yun-zhi, XU Xue-fei, ZHANG Ji-biao 2014, 23 (5):  609-613.  Abstract ( 329 )   HTML ( 3 )   PDF (572KB) ( 343 )   PURPOSE: To discuss the relationships between the level of anxiety, depression and perfectionism in dental patients before orthodontic treatment. METHODS: A modified Corah Dental Anxiety Scale (MDAS), Self-Rating Depression Scale (SDS), Self-Rating Anxiety Scale (SAS) and Chinese Frost Multidimensional Perfectionism Scale (CFMPS) were used in 170 patients before orthodontic treatment. The data was analyzed by independent sample t test, correlation and multiple regression analysis using SPSS16.0 software package. RESULTS: 24.71% of the patients had obvious dental anxiety with MDAS scores≥11, there was significant difference in the scores of SAS, SDS between dental anxiety group and non-dental anxiety group (P<0.01), the scores of concern over mistakes (CM), personal standards (PS), doubts about actions (DA) and organization (OR) of dental anxiety patients were of significant difference compared with that in the non-dental anxiety group (P<0.05). Concern over mistakes (CM), personal standards (PS) and doubts about actions (DA) had significant positive correlations with the scores of SAS and SDS (P<0.01); while organization (OR) had negative correlation with the scores of SDS (P<0.05); Regression analysis showed that the scores of concern over mistakes (CM), organization (OR) and age seemed to be a strong predictor of the scores of SAS and SDS. CONCLUSIONS: The level of anxiety and depression of dental anxiety patients before orthodontic treatment is higher than non-dental anxiety group, and it has significant correlation with perfectionistic tendencies, for dental anxiety of patients with early intervention should be combined with different age and perfectionism personality characteristics. References | Related Articles | Metrics

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A clinical evaluation on the stability of orthodontic mini-implants using resonance frequency analysis FAN Li, MIAO Zhe, TANG Guo-hua 2014, 23 (5):  614-618.  Abstract ( 300 )   HTML ( 2 )   PDF (782KB) ( 227 )   PURPOSE: To evaluate the stability of mini-implant by resonance frequency analysis and to determine the optimal loading timing of orthodontic force. METHODS: Fourteen orthodontic patients who had upper first premolars extraction and needed mini-implants to reinforce the anchorage were enrolled in this study. The patients were divided into 2 groups: delay-loading group and selective-loading group. A joined head mini-implant was inserted in the buccal interradicular area on each side of maxilla for each patient and 28 mini-implants in total were used. Osstell resonance frequency device was used to measure the ISQ (implant stability quotients) value. The measurements were performed immediately after the implant insertion and weekly afterwards until week 16. After the ISQ value was stable, orthodontic force of 150g was loaded on the mini-implants in selective-loading group. The same level of force was applied in delay-loading group at week 12. The data was analyzed by one-way ANOVA and t test using SPSS 19.0 software package. RESULTS: Twenty-three mini-implants were stable during the study. Twelve unloading mini-implants in delay-loading group showed maximal ISQ values immediately after insertion and at week 1 (21.48±5.25). The ISQ values decreased gradually from week 2 to week 5 and reached a plateau after week 6 (11.26±3.36). Eleven mini-implants survived in selective-loading group were then loaded at week 6. There were no significant differences of ISQ values in loading and unloading mini-implants after 6 weeks. The remaining 5 mini-implants were loosing during the first 4 weeks, which showed a significant lower initial ISQ values compared to the successful implants. CONCLUSIONS: The stability of mini-implants decreases 1 week after insertion and maintains after 6 weeks. Orthodontic loading after week 6 has no influence on the stability. Lower initial stability is an important factor for the failure of mini-implants. References | Related Articles | Metrics

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Correlation analysis of VEGF and PTEN expression in gingival carcinoma LI Jing-dong, LIANG Rui-ying, ZHAO Yan-ping, XU Yan-li 2014, 23 (5):  619-623.  Abstract ( 300 )   HTML ( 1 )   PDF (1604KB) ( 239 )   PURPOSE: To study the expression of vascular endothelial growth factor (VEGF) and phosphatase and tensin homolog (PTEN) in gingival carcinoma and their correlation in order to provide reference for clinical treatment. METHODS: Sixty-six gingival cancer patients were determined by pathological examination, among which 31 were well-differentiated, 20 were moderately differentiated and 15 were poorly differentiated.15 adjacent normal tissues were chosen as control group. The expression of VEGF and PTEN was examined by immunohistochemical method. Correlation analysis was performed with SPSS13.0 software package. RESULTS: The positive rate of PTEN in control group was significantly higher than other groups (P<0.05). The expression of VEGF in poorly differentiated group was significantly higher than other groups (P<0.05). Correlation analysis showed that the expression of VEGF was positively correlated to recurrence and lymph node metastasis (P<0.05); PTEN was negatively correlated to recurrence and lymph node metastasis (P<0.05); VEGF and PTEN in gingival carcinoma was negatively correlated (P<0.05). CONCLUSIONS: The increased expression of VEGF and decreased expression of PTEN in gingival carcinoma may play a mutual role in the development of gingival cancer. References | Related Articles | Metrics

Clinical Reports

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Application of sonic endo-instruments in combination with Mtwo Ni-Ti files in root canal preparation of molars CHEN Zhan-hong 2014, 23 (5):  624-627.  Abstract ( 338 )   HTML ( 1 )   PDF (583KB) ( 206 )   PURPOSE: To evaluate the clinical outcome of sonic endo-instruments in combination with Mtwo Ni-Ti files in root canal preparation of molars. METHODS: One hundred patients (118 first molars, 428 root canals) were included in this study, they were randomly assigned into 2 groups (n=50).Group 1 was shaped with sonic endo-instruments in combination with Mtwo Ni-Ti files,while group 2 was treated with stainless-steel files, both groups were obturated with lateral condensation technique. The time of root canal shaping, acute post-operative pain, the quality of the root canal filling and the success rate after 1 year were recorded and analyzed using SPSS 11.0 software package. RESULTS: The average preparation time in group 1 was (5.3±0.6)min/canal and (12.7±0.9) min/canal in group 2 (t=100.89,P<0.001). The rate of acute postoperative pain was significantly lower （χ2=4.87, P<0.05）in group 1 (8.20%) than in group 2 (22.81%); in group 1, 92.86% root canals were filled adequately while only 78.92% in group 2, the difference was significant (χ2=17.45, P<0.05);higher success rate (χ2=3.95, P<0.05) after 1 year was achieved in group 1 (91.80%) compared with group 2 (78.95%). CONCLUSIONS: Compared with stainless-steel files, sonic endo instruments in combination with Mtwo Ni-Ti files in root canal preparation of molars seem more effective, cause less postoperative pain and offer higher success rates. References | Related Articles | Metrics

Systematic Review

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Effectiveness of acellular dermal matrix and parotid fascia in preventing Frey’s syndrome: meta analysis XIAO Meng, SHI Liang, LIU Yun-sheng 2014, 23 (5):  628-633.  Abstract ( 367 )   HTML ( 0 )   PDF (1114KB) ( 207 )   PURPOSE: To evaluate and compare the effectiveness of acellular dermal matrix (ADM) and parotid fascia in preventing Frey’s syndrome. METHODS: A literature research was performed using Wanfang Database, Chinese Biological Literature Database, China National Knowledge Infrastructure and Chinese Scientific Journals database of VIP from 2001 to 2013. Relative ratio (RR) was calculated and meta analysis was performed by Review Manager 5.2. RESULTS: A total of 16 controlled studies were included. Meta analysis showed that the use of ADM and preservation of the parotid fascia could significantly reduce the risk of Frey’s syndrome. The subjective incidence was decreased by 71% and 87%, and objective incidence was reduced by 64% and 85%, respectively. Significant difference was found between ADM and parotid fascia in reducing subjective incidence, in which ADM seemed to be more effective. CONCLUSIONS: The present study suggested that parotid fascia should be adopted as an effective method to reduce Frey’s syndrome in most circumstances for patients with benign parotid tumors. For those whose parotid fascia could not be preserved, ADM might be another good choice. References | Related Articles | Metrics

Dental Education

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Application of role-play simulation in pre-clinical practice of the fourth grade students in department of endodontics ZHU Lin-lin, QIU Li-hong, QU Liu, XUE Ming, YAN Lu 2014, 23 (5):  634-637.  Abstract ( 186 )   HTML ( 0 )   PDF (566KB) ( 264 )   PURPOSE: To apply role- play simulation in pre-clinical practice of the fourth grade students in department of endodontics. METHODS: Thirty-two students were randomly divided into 2 groups, there were 16 students in each group. Students in one group were taught with role-play simulation while the other group with lecture-based learning method. The teaching effect was measured with examination and questionnaire survey. The data was analyzed by using SPSS 17.0 software package. RESULTS: There were no significant differences in basic knowledge, case analysis and oral examination between 2 groups (P>0.05), but there was significant difference in history taking and medical records writing, practical examination and total scores between 2 groups (P<0.05). The role-play simulation was generally approved by both teachers and students in experimental group. CONCLUSIONS: The abilities of the fourth grade students can be developed by role-play simulation in different aspects. Role-play simulation can be applied in pre-clinical practice of the fourth grade students in department of endodontics. References | Related Articles | Metrics

Case Report

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Treatment of mandibular first premolars with complex root canals: report of 2 cases YU Xiao-fei, SUN Pei, ZHANG Hui, DENG Jing, CAO Ying-xiu 2014, 23 (5):  638-640.  Abstract ( 311 )   HTML ( 4 )   PDF (554KB) ( 194 )   Mandibular first premolars have complex root canals. Double root canals and three root canals usually happen. Clinicians should be aware of the normal anatomy of root canal system and vigilant about the possibility of canal variation. In this paper, two cases of mandibular first premolars with double (2-2, Verlucci) and three(1-3,Verlucci) root canals were reported. The root canal type and its incidence were discussed. Clinicians should carefully explore to confirm the existence of variation and avoid missed canals, which are necessary for a successful root canal therapy. References | Related Articles | Metrics