Shanghai Journal of Stomatology

Effect of sintering temperature on mechanical properties of dental zirconia toughened alumina ceramics

FAN Jiang-yuan, LIN Ting-ting, HU Fang-xuan, ZHENG Rui-bin, FAN Fan, MA Jian-feng

2017, 26 (2): 129-133. doi: 10.19439/j.sjos.2017.02.001

Abstract ( 468 )

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PURPOSES: To investigate the effect of sintering temperature on mechanical properties of dental zirconia toughened alumina (ZTA) ceramics prepared by gel-casting technique. METHODS: The samples prepared by gel-casting were sintered at 1100, 1200, 1250, 1300 and 1400℃ for each group. The flexural strength, fracture toughness, Vickers hardness and brittleness index were obtained and microscopic morphology of each group was observed under scanning electron microscope (SEM). The data were statistically analyzed using SPSS 19.0 software package. RESULTS: The flexural strength, fracture toughness and Vickers hardness increased with the increasing sintering temperature during 1100~1400℃. The lowest brittleness index (0.74±0.16) μm^-1/2 was observed in group sintered at 1200℃ and the highest (2.76±0.14) μm^-1/2 was at 1400℃ (P<0.05), while the flexural strength of these two groups was (46.89±3.24) MPa and (349.64±54.72) MPa, respectively. CONCLUSIONS: The ZTA dental ceramics exhibit good machinability with proper sintering temperature (1200℃) and the strength meets the requirement of clinical application.

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Elimination of Entercoccus faecalis with different disinfection methods in root canals in vitro

SUN Chu-wen, ZHU Ya-qin

2017, 26 (2): 134-138. doi: 10.19439/j.sjos.2017.02.002

Abstract ( 343 )

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PURPOSES: To compare the elimination effect against E.faecalis in root canals with different methods. METHODS: Fifty extracted premolars with single root canal were selected. After cleaning and autoclaving, they were contaminated by E.faecalis and incubated for 28 days as models. Then the models were randomly and equally divided into 5 groups and treated as below: specimens in group A were treated with saline irrigation, specimens in group B were treated with 3% NaClO irrigation (as positive control), specimens in group C were treated with PUI, specimens in group D were treated with diode laser radiation, specimens in group E were treated with combination of PUI and diode laser radiation. The specimens from root canals were collected by paper points. The bacterial suspensions were later serially diluted and plated on tryptic soy agar plates to enumerate the CFUs after 48 hours. Statistical analysis was performed using SAS 8.02 software package. RESULTS: As with all parts of the root canal in aggregate, the CFUs of the specimens treated with PUI, diode laser radiation and the combination of them were significantly lower than the specimens treated with saline irrigation (P<0.01), but there was no significant difference among 3 groups (P>0.05). However, the specimens treated with 3% NaClO irrigation had the best effect of disinfection. The number of CFUs in the specimens treated with 3% NaClO was almost zero. There was no significant difference between this group and others in CFUs(P<0.01). CONCLUSIONS: Specimens treated with PUI, diode laser radiation and the combination of them showed great effect of elimination against biofilm of Enterococcus faecalis compared with saline irrigation. Irrigation with 3% NaClO was the most efficient method in this experiment.

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Research on physical and mechanical properties, crown accuracy by using self- made FUS-invest dental investment

WU Jin-shuang, XING He-lin, DONG Chao-fang, GUO Tian-wen, YANG Se-fei

2017, 26 (2): 139-145. doi: 10.19439/j.sjos.2017.02.003

Abstract ( 336 )

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PURPOSES: To evaluate the physical and mechanical properties of pure titanium castings cast by self- made FUS-invest dental investment, and evaluate casting accuracy. METHODS: Seven pure titanium castings were cast by self-made FUS-invest zirconium investment and analyzed using servo hydraulic dynamic experiment system (JJG139-83 standard), scanning electron microscope and energy spectrum analysis. Thirty-eight crowns of pure titanium were cast by two different methods. One cast by FUS-invest zirconium embedding material was used for experiment and the other cast by phosphate embedding material was used as control. Casting accuracy was assessed through measuring the difference value d at the marginal marker points and distance between casting pieces of wall and working modes of casting were examined under microscope. Scanning electron microscope with energy-dispersive spectrum (EDS) was used to analyze the status of composition of the casting surface. SPSS 17.0 software package was used to investigate the difference of two groups. RESULTS: ①Qualitative analysis of servo hydraulic dynamic experiment system showed various mechanical properties: elastic modulus (123.5±14.2) GPa, yield strength (569.3±16.5) MPa, tensile strength (668.4±16.1) MPa, elongation (4.5±0.2)%. EDS analysis of the fracture was observed at different depth (13, 25, 50, 350 μm) under the surface of pollution layer, a little Si and Fe with different atomic percentage was found but no Zr. ②No significant difference (P>0.05) was found between each group of four markers on the marginal fit, and internal fit, whereas significant difference (P< 0.01) was found at different marker point. CONCLUSIONS: The mechanical properties of commercially pure titanium casting by self-made FUS-invest zirconium-based investment can meet the qualification of dental metal materials, although elongation was a little lower. Both the marginal adaptation and internal fit between the two groups had no significant difference. The mean marginal difference was 46 μm, the mean internal difference at axial angle was 56 μm and approximately 0 at axial wall.

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Effect of estrogen on genioglossus and hypoglossal nucleus of female rats

SUN Bing-cheng, LIU Lei, YANG Lin, ZOU Min, HOU Yu-xia

2017, 26 (2): 146-150. doi: 10.19439/j.sjos.2017.02.004

Abstract ( 317 )

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PUEPOSE: To study the hypoglossal nucleus spontaneous discharge and genioglossus function of SD rats with different estrogen levels, and explore the possible central pathways of estrogen protecting upper airway stability. METHODS: Thirty SD rats were randomly divided into 3 groups: sham operation group (Sham), ovariectomized group (OVX) and ovariectomized + estrogen covering group (OVX+E2). The hypoglossal nucleus spontaneous discharge frequency and maximum amplitude of spontaneous discharge were measured with extracellular recording technique;BL-420 biological was used to detect the genioglossus EMG and contraction. The measurements included the average frequency, the maximum frequency, the integral amplitude, the maximum amplitude of the genioglossus, the amplitude of the evoked EMG, the critical fusion frequency, the 50% tonic contraction, and the intensity of the stimulus. SPSS 13.0 software package was used to analyze the data with One-way ANOVA. RESULTS: The hypoglossal nucleus spontaneous discharge frequency and maximum amplitude of spontaneous discharge in OVX group were significantly lower than the Sham group and OVX+E2 group (P<0.05). The genioglossus EMG maximum frequency, average frequency, amplitude and integral maximum discharge magnitude, 50% tonic contraction drive of genioglossus in OVX group were significantly lower than the Sham and OVX+E2 group (P<0.05); the threshold stimulation strength and critical fusion frequency in OVX group were significantly higher than the Sham and OVX + E2 group (P<0.05); there was no significant difference between OVX+ E2 group and the Sham group (P>0.05); there was no significant difference among the three groups (P>0.05). CONCLUSIONS: Estrogen changes excitability of hypoglossal nucleus and affect contraction of genioglossus. Estrogen levels can affect genioglossus contraction function and the ability of resistance to fatigue.

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Investigation of the effect of nuclear factor κB on inflammatory cell recruitment phenotype of oral cancer associated macrophage

ZHOU Xiao-tian, CHEN Dong, JIN Zhen-ning, HUANG Ke, LIN Jie, MEN Yi, LI Chun-jie

2017, 26 (2): 151-155. doi: 10.19439/j.sjos.2017.02.005

Abstract ( 245 )

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PURPOSES: To explore the ability of nuclear factor κB (NFκB) in sustaining inflammatory cell recruitment phenotype of oral cancer associated macrophages, by using NFκB inhibitor(-Bay11-7082). METHODS: By primary culture, murine macrophages were harvested. Cal27 conditioned medium (CM) and Bay11-7082 were applied for stimulation of the macrophages. RT-PCR and ELISA were used for detecting the inflammatory cell recruitment related chemotactic factors. GraphPadPrism5 was used for statistical analysis. RESULTS: Bay11-7082 prevented the contour change into a spindle shape via Cal 27 CM. It also attenuated MCP-1, GM-CSF, MCP-5 and CCL-5 mRNA increase after Cal 27 CM stimulation (P<0.05). At protein level, impeding NFκB activation could significantly prevent MCP-1 and GM-CSF secretion from oral cancer associated macrophage (P<0.001). CONCLUSIONS: NFκB signaling may play a key role in sustaining the inflammatory cell recruitment phenotype of oral cancer associated macrophages.

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Effects of EMD on relapse and root repair after orthodontic tooth movement in rats

HU Qin, XU Xiao-lin, ZHOU Jian-ping, DAI Hong-wei

2017, 26 (2): 156-161. doi: 10.19439/j.sjos.2017.02.006

Abstract ( 339 )

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PURPOSE: To study the effect of enamel matrix derivative(EMD) on root repair and tooth movement relapse after orthodontic tooth movement in rats. METHODS: Twenty 10-weeks old male rats were divided into experimental and control group randomly (n=10). 100 g force was exerted to the left maxillary first molars for 14 days and then removed. EMD was injected in rats in the experimental group since appliance was removed. The control group received no injection. Micro-CT was taken to analyze the changes of root resorption volume and distance of tooth movement. The differences were analyzed by SPSS19.0 software package. RESULTS: Fourteen days after device removal, the repair volume of root resorption lacunae in the experimental group and the control group were (0.0295±0.0052)×107 μm3，(0.0189±0.0086)×107 μm3, respectively. The relapse distance and relapse percentage after tooth movement were (0.089±0.005) mm, (64.76±3.63)%, (0.127±0.010) mm and (92.28±1.90)%, respectively. Statistical analysis showed the repair volume of root resorption lacunae, the relapse distance and relapse percentage were statistically significant 14 days after device removal (P<0.05). CONCLUSIONS: EMD can enhance the effect of root repair and decrease early relapse after orthodontic tooth movement in a certain extent.

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Cytotoxicity of carboxymethyl chitosan zinc and peptide to human periodontal ligament cells

GUO Hui, PAN Ke-qing, DENG Jing, LIU Xue-yu, SONG Jia

2017, 26 (2): 162-166. doi: 10.19439/j.sjos.2017.02.007

Abstract ( 359 )

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PURPOSES: The purpose of this investigation was to study the cytotoxicity of carboxymethyl chitosan zinc and peptide to human periodontal ligament cells in vitro, in order to provide a reference for understanding materials' safety. METHODS: The primary cells were obtained from human periodontal tissues and cultured. The cultured cells were identified by observing the shape under microscope and by immunocytochemical method. HPDLCs were cultured in different concentrations of the tested materials extract and the activity of cells was evaluated using CCK-8 assay. The cytotoxicity grade was determined in term of the cell relative growth rates. The concentration of the tested materials extract was 100%, 75%, 50% and 25% in group 1-4, respectively. The fifth group had no materials. All statistical analysis was performed using SPSS 17.0 software package. RESULTS: The primary cells owned fibroblasts' shape. Immunocytochemical analysis showed the cells were stained positively to antibodies against vimentin, and negatively to antibodies against cytokeratin, which indicated that they were external embryo mesenchymal cell. The cell relative growth rates were more than 100%, no matter the concentrations of materials extract were. The cytotoxicity grade of CMC-Zn⁺-P was 0. CONCLUSIONS: CMC-Zn⁺-P exhibits no cytotoxicity to HPDLCs in vitro, which meets the requirements of the national standard.

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Experimental study on osteogenesis of acellular porcine pericardium in guided bone regeneration

GAO Jun-zhao, ZHANG Xue-jian, HOU Jia-li, DENG Yue, LI Yun-peng

2017, 26 (2): 167-170. doi: 10.19439/j.sjos.2017.02.008

Abstract ( 412 )

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PURPOSES: To observe the retention time and effect of acellular porcine pericardium (APP) in bone regeneration for rabbit femoral bone defects. METHODS: APP was prepared as follows: fresh porcine pericardium was chosen, high and low osmotic NaCl solution were used to soak the specimen alternately, trypsin+EDTA were used for digest, and then immersed with TritonX-100, cross-linked by using glutaraldehyde. 24 New Zealand rabbits were selected, and the area of bone defect was created 8 mm×8 mm×5 mm in size on bilateral distal femur. Stochastic method was used for grouping. One side of bone defect was covered with APP (experimental group); and the other side was covered without APP (control group). General observation, X-ray examination, histological examination, and bone mineral density (BMD) were performed 4 weeks, 8 weeks and 12 weeks after operation. SPSS18.0 software package was used for statistical analysis. RESULTS: After surgery, all wounds healed without complications. Under general observation, there were some fibrous cysts covered on the surface of APP. BMD (P<0.05) in the experimental group was significantly greater than that in the control group. On histological examination, the rate of osteogenesis in the experimental group was faster than that in the control group. CONCLUSIONS: Bone regeneration can be achieved using APP in the repair of rabbit bone defects. The retention time of APP can meet the needs of osteogenesis.

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Effect of PKC inhibition on cell migration and invasion of oral squamous cell carcinoma

CHEN Zhong, XU Yong, JI Qing

2017, 26 (2): 171-174. doi: 10.19439/j.sjos.2017.02.009

Abstract ( 203 )

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PURPOSES: By using HN4 cells, the correlation among protein kinase C(PKC), P120-catenin(P120ctn) and E-cadherin (E-cad) was investigated, and the role of them in migration and invasion of oral squamous-cell cancer(OSCC) was evaluated. METHODS: Plasmid pGFP-V-RS-P120ctn shRNA was used to transfect HN4 cells to significantly reduce the expression of P120ctn and PKC inhibitor staurosporine (STS) was added. mRNA and protein expression of PKC, P120ctn and E-cad were tested and Transwell cell invasion and cell migration assay was used to test the invasion and migration capacity before and after PKC inhibition. Statistical analysis was performed using SPSS 18.0 software package. RESULTS: When PKC was inhibited by STS, the expression of P120ctn and E-cad in OSCC cells were increased and the migration and invasion capacity of tumor cells decreased significantly (P<0.05). CONCLUSIONS: PKC may be involved in the process of HN4 migration and invasion by regulating cell adhesion through the effect of P120ctn and E-cad.

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Changes of cementum endotoxin levels in different teeth with periodontitis treated with root conditioning

FU Chang-sheng, LIU Rong-sen, LUO Yun, OU Long, LI Ying-chao, ZHANG Xian-hua, TIAN Lei, DU Yan

2017, 26 (2): 175-179. doi: 10.19439/j.sjos.2017.02.010

Abstract ( 275 )

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PURPOSES: To observe the changes of endotoxin levels after different teeth with periodontitis were treated with different methods. METHODS: Six healthy premolars extracted for orthodontic reasons and 36 posterior teeth extracted due to severe periodontitis were selected. Each tooth was processed from two 4 mm×4 mm×1 mm cementum pieces 2 mm under the cementum-enamel junction, each tooth with periodontitis was numbered. Healthy teeth served as negative control group, one of the two tablets from each tooth with periodontitis was selected in the periodontitis group, which was not treated with root surface treatment. The remaining 36 teeth with periodontitis were randomly divided into 6 groups: SRP group, SRP + antimicrobial peptide A group , SRP + antimicrobial peptide B group, SRP + EDTA group, SRP + Er:YAG laser group and SRP + Nd:YAG laser group. Endotoxin concentration in each tooth was determined by chromogenic substrate limulus reagent. The endotoxin concentration in each tooth was recorded according to the serial number, and the changes of endotoxin concentration were calculated before and after treatment. SPSS17.0 software package was used to analyze the data. RESULTS: Compared with the teeth with periodontitis, endotoxin concentration decreased to varying degrees, there were significant differences in each treatment group(P<0.01). Compared with SRP group, endotoxin levels in SRP + antimicrobial peptide A group, SRP + antimicrobial peptide B group, SRP + Er:YAG laser group were significantly decreased(P<0.01). No significant difference decreased was from between SRP + EDTA group and SRP + Nd:YAG laser group(P>0.05). CONCLUSIONS: Treatment of teeth with periodontitis using different methods can decrease the level of endotoxin, and the treatment of periodontitis root surface with antimicrobial peptide A + SRP may be more effective.

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Differentially expressed genes between the human mandible- and ilium- derived mesenchymal cells

YANG Quan-quan, WANG Jiao, LI Zhi-yong

2017, 26 (2): 180-183. doi: 10.19439/j.sjos.2017.02.011

Abstract ( 306 )

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PURPOSES: To explore the differentially expressed genes between human mandible- and ilium- derived mesenchymal cells. METHODS: Differentially expressed genes between the human mandible- and ilium- derived mesenchymal cells were obtained from the GEO database based on the analysis of GEO2R software, then the relationship among these genes were analysed using DAVID and Gene MANIA on-line database. RESULTS: Two hundred and ninety three differentially expressed genes between the human mandible and iliac derived mesenchymal cells were obtained, and most of them were homeobox genes that related to bone development. These genes could also be enriched into different subgroups based on the analysis of DAVID database, such as "skeletal system development", "forebrain development", "limb development" and "WNT signaling pathway". After the analysis from Gene MANIA database, the molecular networks of MSX1, MSX2, HAND2, SIX1, PITX2, OSR2, PAX3 and PRRX1 were built to show that these eight genes exhibited interactions, including co-expression, co-localization, genetic interactions. CONCLUSIONS: There are different gene regulating mechanisms between the human mandible- and ilium- derived mesenchymal cells. It implies that genetic modification may be applied to get iliac derived mesenchymal cells to be more suitable for tissue-engineered repair of jaw.

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Effect of hemostatic agent on bonding strength of deciduous tooth dentin

PAN Qiu-hua, HUANG Da-wei, WANG Qing-tai

2017, 26 (2): 184-187. doi: 10.19439/j.sjos.2017.02.012

Abstract ( 268 )

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PUPPOSE: To investigate the effect of hemostatic agent on bonding strength of deciduous tooth dentin. METHODS: Forty deciduous molars were used to make dentin grinding model and randomly divided into observation group and control group, 20 teeth in each group. Teeth in the observation group were covered with hemostatic agent for 30s, and then washed, followed by processing; while teeth in the control group were subjected to bonding directly. Micro tensile bond strength and micro leakage were measured and compared in the two groups. SPSS19.0 software package was used to analyze the data. RESULTS: Micro tensile bond strength of the observation group was (12.84±2.10) MPa, significantly lower than that of the control group (P<0.05); most resin protrusion in the observation group was > 35 μm and long and dense, extending into the open dentinal tubules; while resin protrusion in the control group was about 7 to 35 μm, with obvious collateral communication. There was no significant difference in the degree of micro leakage between the two groups (P>0.05). CONCIUSIONS: Hemostatic agent has certain impact on the dentin bonding strength of deciduous tooth, special attention should be paid during clinical application.

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Methods and effects of injection of salvianolic acid B combined with triamcinolone acetonide in the treatment of oral submucous fibrosis

XIAO Yi-cai, JIAN Xin-chun, ZHENG Lian, ZHOU Chao, DU Yong-xiu, ZHOU Ting, WANG Bin-ping

2017, 26 (2): 188-192. doi: 10.19439/j.sjos.2017.02.013

Abstract ( 448 )

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PURPOSES: To introduce the methods of triamcinolone acetonide (TA) and salvianolic acid B(SA-B) intralesional injection in the treatment of oral submucous fibrosis and evaluate the treatment effects. METHODS: TA combined with SA-B were consecutively applied intralesionally 1 time weekly for 30 times. The technique of intralesional injection was that syringe needle be emptied into submucous tissues 1 cm posterior to the corner of oral cavity running from the front to retromolar area by pushing the injection, then the syringe needle retained to the original point and upward from the front to retromolar area by pushing the injection, finally the syringe needle returned to the starting point and downward from the front to retromolar area by pushing the injection. Mouth opening, the color change of the buccal mucosa and the increase of capillary vessels as determined by degree I-IV visual analog scale were evaluated at 12, 24, and 36 month. The data were analyzed with SPSS 21.0 software package. RESULTS: One hundred and fourteen subjects fulfilled the study without obvious adverse reactions. After treatment for 36 months , the net gain in mouth opening of the early stage group,middle stage group and advanced stage group was (12.0±1.2) mm, (14.5±2.4) mm and (15.5±1.5) mm, respectively. The response rate of color change of the buccal mucosa and the increase of capillary vessels in early stage group, middle stage group and advanced stage group after treatment for 36 months was 100%, 94.7% and 90.7%, respectively. CONCLUSIONS: Triamcinolone acetonide and salvianolic acid B intralesional injection is effective in the treatment of oral submucous fibrosis.

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Morphometric analysis of maxillofacial bone in 48 patients with ectodermal dysplasia

WANG Hao-wei, WANG Feng, HUANG Wei, ZHOU Wen-jie, WANG Yue-ping, WU Yi-qun

2017, 26 (2): 193-197. doi: 10.19439/j.sjos.2017.02.014

Abstract ( 432 )

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PURPOSES: The study was performed to analyze the maxillofacial morphology of 48 patients with ectodermal dysplasia (ED) and to provide some reference for implant treatment of ED patients. METHODS: The study collected the clinical data and lateral cephalometric radiographs of 48 patients with ED treated between June 2013 and October 2016. The patients were grouped as follows: group 1, 23 patients, at least with two kinds of ectodermal disorder, besides hypodontia; group 2, 25 patients, only with one kind of ectodermal disorder, besides hypodontia. The number of missing teeth and maxillofacial cephalometric parameters were compared between 2 groups. SPSS 17.0 software package was performed for statistical analysis. RESULTS: The number of missing teeth was significantly larger in group 1(22.3±5.8) than group 2 (12± 6.6) (P<0.05). The number of retained deciduous teeth was significantly larger in group 1 (8±4) than in group 2 (2.4±2.7) in females (P<0.05). Cephalometric analysis showed a reduced maxilla length (ANS-Ptm), retrusive maxilla (S-Ptm, SNA, NA-PA), a normal size (S-Co) and length (Co-Po) of mandible, a protruding mandible (NP-FH) and chin (Y axis), skeletal Angle Ⅲ malocclusion(ANB<0) and a reduced facial height (N-Me) in two groups. SNA, NA-PA, ANS-Ptm, S-Ptm and Y axis were significantly decreased and NP-FH was significantly increased in group 1 compared to group 2 in males (P<0.05). CONCLUSIONS: Maxillofacial morphology of ED patients typically presented a reduced maxilla length and retrusive maxilla, a normal size and length of mandible, a protruding mandible and chin, skeletal Angle Ⅲ malocclusion and a reduced facial height. The severity of abnormalities in maxillofacial bone morphology was correlated positively with absence of permanent teeth. Furthermore, retained deciduous teeth might have positive effect on the development of maxillofacial bone.

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Expression of PTPRZ1 in oral squamous cell carcinoma originated from oral submucous fibrosis and its clinical significance

ZHU Rong, JIAN Xin-chun, LIU De-yu, ZHOU Chao, WANG Yuan

2017, 26 (2): 198-203. doi: 10.19439/j.sjos.2017.02.015

Abstract ( 395 )

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PURPOSES: This study was aimed to detect the expression of PTPRZ1 in oral squamous cell carcinoma (OSCC) originated from oral submucous fibrosis (OSF), and discuss its role in the development and progression of OSCC originating from OSF as well as its clinical significance. METHODS: Immunohistochemisty (IHC) and Western blot (WB) for the expression and distribution of PTPRZ1 were carried out in 36 cases of OSF transforming into OSCC, 23 cases of OSCC and 21 cases of healthy controls. The data were analyzed by Chi-square test using SPSS 21.0 software package. RESULTS: IHC results demonstrated that the expression of PTPRZ1 in OSCC originated from the OSF was strongly positive and the rate of positive expression was 72.22%; expression of PTPRZ1 in OSCC was weakly positive, the positive rate was 43.47%; and the expression of PTPRZ1 in healthy controls was negative. The rate of PTPRZ1 positive expression was significantly higher in OSCC originated from OSF and OSCC with non-OSF than that of the healthy controls (P<0.01). The positive expression rate of OSCC originated from OSF was significantly higher than that of OSCC with non-OSF (P<0.05).WB results showed the expression of PTPRZ1 was weak in the healthy controls and in OSCC with non-OSF, but strong in OSCC originated from OSF. Correlation analysis between PTPRZ1 and clinical data showed PTPRZ1 was correlated with recurrence and metastasis positively (r_k=0.642, P<0.05; r_k =0.656, P<0.05). CONCLUSIONS: Differential expression of PTPRZ1 in OSCC originating from OSF and OSCC with non-OSF was significant. PTPRZ1, which plays an important role in the processes of development, invasion and metastasis of OSCC originated from OSF, can be used as a molecular marker for early diagnosis and targeted gene for treatment of OSCC originating from OSF.

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A survey on knowledge, attitude and practice related to evidence-based dentistry among dental students

CHANG Zhong-fu, ZHU Ce, TAO Dan-ying, FENG Xi-ping, LU Hai-xia

2017, 26 (2): 204-208. doi: 10.19439/j.sjos.2017.02.016

Abstract ( 279 )

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PURPOSES: To investigate the knowledge, attitude and practice related to evidence-based dentistry among dental students, and to provide a reference for targeted evidence-based dentistry teaching and practice evidence-based dentistry in dental students. METHODS: Dental students who attended the internship in Shanghai Ninth People's Hospital and Pudong People's Hospital were invited to attend this survey. Information on knowledge, attitude and practices related evidence-based dentistry was collected through questionnaires. SPSS 21.0 software package was used for data analysis. RESULTS: A total of 62 dental students attended this survey. Evidence-based dentistry related knowledge and attitude scores were 5.5±1.9 and 5.1±1.0, respectively. Over three quarters of students took courses on evidence-based medicine, while around half of students (56.5%) self-reported that they knew little about evidence-based medicine. 70.5% students practiced evidence-based dentistry less than once in the process of clinical decision making per week. The majority of students (80.3%) used MEDLINE or other databases to search for practice-related literature less than once per week. 63.9% students used practice guideline. The top three barriers to practice evidence-based dentistry were lack of information resources, insufficient time and lack of search skills. CONCLUSIONS: Evidence-based dentistry related knowledge and practice among dental students is deficient, whereas they hold positive attitude on practice. The top three barriers to practice evidence-based dentistry are lack of information resources, insufficient time and lack of search skills.

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The relationship between periodontitis and arterial sclerosis without genetic confounding

HAN Ya-kun, LIN Xiao-ping

2017, 26 (2): 209-212. doi: 10.19439/j.sjos.2017.02.017

Abstract ( 216 )

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PURPOSES: The aim of this study was to evaluate periodontitis as a significant risk factor related to arterial sclerosis after eliminating genetic confounding. METHODS: Fifty two monozygotic twin pairs, 104 patients, were divided into 3 groups. group A: 24 pairs, 48 healthy people, as the blank group; group B: 28 patients with periodontitis, as the control group; group C: 28 patients with periodontitis, as the treatment group. The sample in group B and C had the same gene type. The index of CRP, IL-6, TNF-αand IMT were detected before treatment, 6 and 12 week after treatment. The data were analyzed using SPSS 17.0 software package. RESULTS: The index of CRP, IL-6, TNF-α and IMT decreased after treatment in group C, there was no significant change in group A and B at each check point. CONCLUSIONS: Periodontitis can promote the development of sclerosis without the intervening of gene.

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Investigation of related risk factors of temporomandibular disorders in 109 patients

HU Xin-xin, ZHU Yao-min, HE Liu-ting, GU Ying, LIANG Zhi-gang, ZHENG Cang-shang

2017, 26 (2): 213-216. doi: 10.19439/j.sjos.2017.02.018

Abstract ( 412 )

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PURPOSES: To investigate the related risk factors of temporomandibular disorders(TMD), and to provide evidences for clinical prevention. METHODS: One hundred and nine TMD patients were included in the study as case group, while 109 people with no TMJ symptoms and signs were selected randomly as control group. All subjects fulfilled questionaires. Logistics regression analysis was used to analyze the data with SPSS 22.0 software package. RESULTS: Females patients were more common than males, with 20~29 age group accounting for 44%. The proportions of patients with habits of bruxism or clenching, unilateral mastication and maxillofacial injure history were significantly greater than those of control group (P<0.05). The proportions of patients with life stress and habits of stay-up late, chewing hard food and orthodontic treatment history showed no significant difference compared with the control group (P>0.05). CONCLUSIONS: TMD has a higher prevalence in female than in male, with a peak incidence in 20~29 age group. Habits of bruxism or clenching, unilateral mastication and maxillofacial injury history may be risk factors of TMD, while life stress, habits of stay-up late, chewing hard food and orthodontic treatments show no significant correlation with TMD.

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Comparison of the differences in pain and the effect of ibuprofen in reducing endodontic flare-up after single-visit root canal therapy between Uyghur and Han patients with chronic apical periodontitis

YAN Lei, WANG Xin-ying, WAN Na, YIN Yan-jiao, WU Pei-ling

2017, 26 (2): 217-221. doi: 10.19439/j.sjos.2017.02.019

Abstract ( 455 )

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PURPOSES: To compare the incidence of postoperative pain of chronic periapical periodontitis patients with root canal therapy between Han and Uygur, and the effect of ibuprofen in reducing endodontic flare-up after single-visit root canal therapy between Uyghur and Han patients with chronic apical periodontitis, in order to provide a basis for clinical administration. METHODS: Two hundred and fifty Uyghur and 250 Han patients with chronic apical periodontitis in their incisor, canine and premolar were collected, and randomly divided into 2 groups: experimental group and control group. After single-visit root canal therapy, Uyghur patients in the experimental group (UEG) and Han patients in the experimental group (HEG) took ibuprofen capsules according to the drug instructions; while Uyghur patients in the control group (UCG) and Han patients in the control group(HCG) took placebo capsules. Both doctors and patient kept blind from the drug capsules and group of the patients. The incidence, degree of endodontic Flare-up at 6, 12, 24, 48, 72 hours and 1 week after root canal therapy were recorded and analyzed by χ² test using SPSS11.0 software package. RESULTS: During the experiment, the incidence of E flare-up in Uygur patients was higher than in Han patients; the incidence of E flare-up in different groups in orders from high to low was: UCG>HCG>UEG>HEG. Chi-square test showed that there were significant differences between the two groups. In view of time distribution, most of flare-up happened between 24~48 hours after root canal therapy with the highest degree in all 4 groups. Regardless of the incidence or degree of flare-up, HEG and HCG were significantly greater than UEG and UCG. CONCLUSIONS: Ibuprofen can reduce and prevent flare-up for both Uyghur and Han patients, but it has better effect on Han patients.

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Effect of functional appliance on upper airway in adolescent patients with skeletal Class Ⅱ malocclusion

LI Xuan, ZHOU Hui-ling, LOU Xin-tian, HU Zheng, SHEN Gang

2017, 26 (2): 222-227. doi: 10.19439/j.sjos.2017.02.020

Abstract ( 284 )

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PURPOSES: To investigate the effect of functional appliance on upper airway in adolescent patients with skeletal Class Ⅱ malocclusion based on cone-beam CT (CBCT). METHODS: Thirty adolescent patients (male:female=1:1) with skeletal Class Ⅱ malocclusion and their 30 counterparts with skeletal Class I malocclusion were selected. Skeletal Class Ⅱ malocclusion patients were treated with Activator for 12 months on average, meanwhile skeletal Class I malocclusion patients were treated with fixed appliance without extraction. Cone-beam CT (CBCT) films were taken before and 12 months after treatment. Films of skeletal Class Ⅱ malocclusion patients were measured (items about skeletal and upper airway, and the outline of upper airway depicted with 3D reconstruction) and compared with the reference standards and the measurements of their counterpart patients with skeletal Class I malocclusion. Independent t test was performed in inter-group comparison and paired t test was performed in inner-group comparison using SAS 8.0 software package. RESULTS: Before treatment, patients with skeletal Class Ⅱ malocclusion showed decreased SNB and APDI value, increased ANB, Wits, and OJ compared with standard value and value of skeletal Class I malocclusion patients. In addition, decreased MPW and PAS value, and downsized volume of upper airway and transverse diameter minimum were found in skeletal Class Ⅱ malocclusion patients. After treatment with Activator, patients with skeletal Class Ⅱ malocclusion showed increased MPW and PAS value, and enlarged volume of upper airway and transverse diameter minimum. All values of skeletal items of patients with skeletal Class Ⅱ malocclusion showed trends to get close to the reference standards and the values of skeletal Class I malocclusion patients. There was no significant difference between different genders of the two groups. CONCLUSIONS: Patients with skeletal Class Ⅱ malocclusion have constructed upper airways. Treatment with Activator can increase the MPW and PAS values and enlarge volume of upper airway and transverse diameter minimum. Functional appliance can ameliorate the narrowness of upper airway for skeletal Class Ⅱ patients.

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Anterolateral thigh flap for reconstruction of defects after en bloc resection of buccal cancer : a retrospective study of 23 cases

DENG Zhi-yuan, FANG Xiao-dan, PAN Hao, HU Yan-jia, TANG Zhan-gui

2017, 26 (2): 228-232. doi: 10.19439/j.sjos.2017.02.021

Abstract ( 507 )

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PURPOSES: This study was aimed to observe the effects of anterolateral thigh flap for reconstruction of tissue defects after en bloc resection of buccal cancer. METHODS: Twenty-three patients with soft tissue defects after en bloc resection of buccal cancer underwent simultaneous reconstruction with anterolateral thigh flap from May, 2013 to May, 2015 were observed. Anterolateral thigh flaps were designed and harvested in form of single or multiple islands to restore the defect in buccal region after surgery. The appearance and function of both the oral and maxillofacial region and the donor site were recorded and evaluated. RESULTS: All the 23 flaps survived. Only 3 of them experienced vascular crisis within 24 hours after surgery, and recovered gradually after salvage. The success rate was 100%. One to three years of follow-up showed satisfying morphology and function for both the receipt sites and the donor sites. Buccal abscess was observed in 1 patient and recovered after rinsing and drainage. Two patients died of recurrence. CONCLUSIONS: Good effects can be achieved using anterolateral thigh flap to reconstruct buccal defects after en bloc resection of cancer, which is suitable for application in clinical practice.

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Safety and efficacy of ultrasound hyperthermia combined with chemotherapy and radical operation for advanced oral squamous cell carcinoma

SHAO Cui-ling, ZHUANG Qian-wei, MENG Jian, GUO Wei, REN Guo-xin, ZHANG Jie, GU Qian-ping, LI Zhi-ping, WANG Xing, GU Jian-min, HAN Kun

2017, 26 (2): 233-236. doi: 10.19439/j.sjos.2017.02.022

Abstract ( 326 )

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PURPOSES: To explore the safety and efficacy of ultrasound hyperthermia combined with chemotherapy and radical operation for advanced oral squamous cell carcinoma (OSCC). METHODS: Nine patients who had definite pathological diagnosis were enrolled in this clinical trail from 2015 to 2016. All patients underwent ultrasound hyperthermia combined with chemotherapy before radical operation. The treatment regime was as follows: Docetaxel and cisplatin (75mg/m²) used on the first day, fluorouracil (750 mg/m²) infused from 1st to 5th day. All patients received 2 cycles of thermo-chemotherapy, the therapeutic temperature was set to be 40-42 ℃, ultrasound hyperthermia was performed for 40 minutes every other day for 5 times. The therapeutic outcomes were evaluated by observation of clinical tumor regression. RESULTS: Of the 9 patients, complete response（CR）was seen in 1 case, partial response (PR) was seen in 3 cases, stable disease（SD）was seen in 5 cases. Complications were not severe and tolerable. CONCLUSIONS: Ultrasound hyperthermia combined with chemotherapy (TPF) may improve the therapeutic effect in advanced OSCC without obvious adverse reactions, and the toxicity and side effects are well tolerated.

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Improving the teaching quality by multiple tools and technology in oral histopathology experimental course

TIAN Zhen, WANG Li-zhen, HU Yu-hua, ZHANG Chun-ye, LI Jiang

2017, 26 (2): 237-240. doi: 10.19439/j.sjos.2017.02.023

Abstract ( 213 )

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PURPOSES: Oral histopathology is a course which needs to be combined with theory and practice closely. Experimental course plays an important role in teaching oral histopathology. Here, we aim to explore a series of effective measures to improve the teaching quality of experimental course and tried to train observation, thinking, analysis and problem solving skills of dental students. METHODS: We re-edited and updated the experimental textbook "guidelines of experimental course of oral histopathology", and published the reference book for experimental course--"color pocket atlas of oral histopathology: experiment and diadactic teaching". The number of clinicopathological cases for presentation and class discussion was increased, and high-quality teaching slides were added and replaced the poor-quality or worn out slides. We established a variety of teaching methods based on the internet, which provided an environment of self-directed learning for dental students. Instead of simple slice-reading examination, a new evaluation system based on computer was established. RESULTS: The questionnaire survey showed that the students spoke positively on the teaching reform for experimental course. They thought that the reform played a significant role in enriching the teaching content, motivating learning interest and promoting self-study. Compared with traditional examination, computer-based examination showed a great advantage on mastering professional knowledge systematically and comprehensively. CONCLUSIONS: The measures adopted in our teaching reform not only effectively improve the teaching quality of experimental course of oral histopathology, but also help the students to have a clear, logical thinking when facing complicated diseases and have the ability to apply theoretical knowledge into clinical practice.

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