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25 April 2022, Volume 31 Issue 2 Previous Issue    Next Issue

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CONTENTS 2022, 31 (2):  112-112.  Abstract ( 66 )   PDF (741KB) ( 74 )   Related Articles | Metrics

Original Articles

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Correlation between low expression of Hsp90 protein in keratinocytes and the number of small extracellular vesicles and its potential clinical significance CHEN Jun, SUN Kai, PAN Lei, DU Guan-huan, SONG Chen-cheng, CHEN Jun-jun, YANG Cheng-long, WANG Yu-feng, TANG Guo-yao 2022, 31 (2):  113-119.  doi: 10.19439/j.sjos.2022.02.001 Abstract ( 256 )   PDF (1225KB) ( 233 )   PURPOSE: To investigate the correlation between the level of heat shock protein 90(Hsp90) and the amount of small extracellular vesicles(sEVs) in keratinocytes. METHODS: Human keratinocytes(HaCaT) were cultured in vivo and divided into wild-type group, short hairpin RNA interference group (shRNA group, low expression of Hsp90), and 17-Allylamino-17-demethoxygeldanamycin group (17-AAG group, Hsp90 protein inhibitor). sEVs were isolated from culture system by ultracentrifugation, and their morphological characteristics were observed under transmission electron microscopy (TEM). Western blotting was applied to identify the biological characteristics of sEVs. The number of sEVs particles was detected by nanoparticle tracking analysis (NTA). GraphPad Prism8.0 software was used to analyze the difference in the number of sEVs among the groups by t test (non-parametric Mann-Whitney U test). RESULTS: HaCaT-derived sEVs, obtained by ultracentrifugation, were consistent with the criteria of morphological and biological identification. No expression of Hsp90 protein was detected in HaCaT-derived sEVs. When interfered with Hsp90-shRNA, the number of sEVs were significantly increased. On day 5, the sEVs number of shRNA-interfering group was (177.4±4.18)×108(n=3), while that of vector group was (82.34±4.83)×108(n=3), and the difference was statistically significant (P<0.0001). After 5 days of inhibition with 17-AAG, the sEVs number of 17-AAG group was （652.5±26.73）×108(n=3) and that of control group was (262.22±5.44)×108(n=3), the difference was statistically significant (P<0.000 1). CONCLUSIONS: Low expression of Hsp90 protein can promote the secretion of sEVs in HaCaT cells. sEVs may be involved in the transfer of molecules between epithelial cells and immune cells. References | Related Articles | Metrics

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Age-related changes in differentiation of bone marrow mesenchymal stem cells and the activity of Notch signaling pathway TANG Zhao-long, JING Wei 2022, 31 (2):  120-125.  doi: 10.19439/j.sjos.2022.02.002 Abstract ( 257 )   PDF (1293KB) ( 207 )   PURPOSE: To explore the age-related changes in differentiation and proliferation of murine bone marrow mesenchymal stem cells (BMSCs) and the activity of Notch signaling pathway in vitro. METHODS: BMSCs were harvested from the whole bone marrow of young, adult and aged C57BL/6 mice and were evaluated for cell-surface protein expression using flow cytometry. After osteogenic and adipogenic induction, osteogenic and adipogenic differentiation ability of BMSCs was evaluated. Cell viability was analyzed by proliferation and migration assays. The expressions of Notch-related genes were analyzed by real-time PCR. The experimental data were analyzed with SPSS 19.0 software package. RESULTS: Alizarin red S and Oil red O staining results indicated that the osteogenic ability of BMSCs gradually decreased with aging, while the adipogenic ability increased. Cell activity assays showed that the proliferative and migrated capacity did not decline with aging significantly, which suggested that the changes of osteogenic and adipogenic differentiation observed in aged BMSCs were not attributed to cell activity but to differentiation potential. Real-time PCR showed the aged cells exhibited significantly higher Notch signaling expression level than the younger ones (P<0.05). CONCLUSIONS: Decreased bone formation capacity and increased adipogenic differentiation ability were noted in aged BMSCs. At the same time, the activity of Notch signaling pathway shows an aging increase which would propose a new idea to restore the damaged osteogenic differentiation ability of aged BMSCs. References | Related Articles | Metrics

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Influence of bilateral coronoidectomy on temporomandibular joint stress distribution after costochondral graft reconstruction: a finite element analysis MAO Yi, CHEN Xu-zhuo, QIN Hai-yi, ZHEN Jin-ze, QIU Ya-ting, HUO Liang, ZHANG Shan-yong 2022, 31 (2):  126-131.  doi: 10.19439/j.sjos.2022.02.003 Abstract ( 376 )   PDF (1861KB) ( 162 )   PURPOSE: To explore the effect of bilateral coronoidectomy on stress distribution after reconstruction of temporomandibular joint (TMJ) by costochondral graft. METHODS: Ten groups of models were established to simulate costochondral graft reconstruction with simultaneously different distances (0, 2, 4, 6, 8 mm) of mandibular advancement, with or without coronoidectomy. Force and stress distribution in the rib-cartilage area were analyzed by finite element analysis. RESULTS: In the process of bilateral joint reconstruction with simultaneously mandible advancement ranging from 0 mm to 8 mm, when the coronoid processes were retained, the forward deformation of the cartilage occurred and the shear force decreased in turn, from 113.2 N to 26.7 N on the left side and from 133.7 N to 1.9 N on the right side. When the coronoid processes were removed, the cartilage deformed backward and the shear force increased successively, from 94.6 N to 188.5 N on the left and 70.1 N to 157.7 N on the right. The stress in the neck was obviously concentrated when mandible advanced 8 mm. CONCLUSIONS: Coronoidectomy has an important impact on stress distribution in the TMJ area, and keeping the coronoid process is beneficial to maintain the mechanical balance. Bilateral CCG reconstruction with coronoidectomy for lengthy mandible advancement (≥ 8 mm) may lead to prominent increase in shear force beyond CCG resistance, resulting in a costal-cartilage junction fracture. References | Related Articles | Metrics

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Effect of miR-199a regulating IGF1 expression on differentiation of osteoblasts under mechanical stimulation LIN Wei-long, WU Xiao-pei, WANG Xiao-ming, HE Wei-wei 2022, 31 (2):  132-137.  doi: 10.19439/j.sjos.2022.02.004 Abstract ( 223 )   PDF (1122KB) ( 190 )   PURPOSE: To investigate the expression change of microRNA (miR) - 199a in MC3T3-E1 cells stimulated by mechanical stretch and its mechanism of osteogenic differentiation. METHODS: MC3T3-E1 cells cultured in vitro were loaded with 12% stretch for 0, 3, 6, 12 and 24 hours, alkaline phosphatase (ALP) activity was detected by ALP activity test kit, the expressions of osteocalcin (OCN), osteoblast specific transcription factor osterix (OSX), Runt related transcription factor 2 (Runx2) mRNA and miR-199a were detected by real-time fluorescence quantitative PCR. MC3T3-E1 cells were divided into control group, stretch group, stretch + miR-NC group and stretch + miR-199a group, and the expressions of miR-199a, OCN, OSX, Runx2 mRNA and protein and ALP activity were observed after 12% stretch and transfection of miR-199a. Alizarin red S (ARS) staining was used to observe calcium nodule formation ability. The target relationship between miR-199a and insulin like growth factor-1 (IGF1) was detected by double luciferase reporter gene assay; in addition, the effect of miR-199a mimic on IGF1 mRNA and protein expression was detected by real-time fluorescent quantitative PCR and Western blot. SPSS 24.0 software package was used to analyze the data. RESULTS: Compared with those at the time point of 0 h, ALP activity and expression level of OCN, OSX and Runx2 mRNA of MC3T3-E1 cells at 3, 6, 12 and 24 hours after mechanical stretch stimulation were significantly higher, while the expression level of miR-199a was significantly lower(P<0.05), and the change was most significant at 12 h. Compared with those in the control group, the expression level of miR-199a was significantly lower in the stretch group, while ALP activity, the expression level of OCN, OSX and Runx2 mRNA and protein, calcium nodule formation level were significantly high in the stretch group(P<0.05); there was no significant difference in the above indexes between the stretch group and stretch + miR-NC group(P>0.05). Compared with stretch + miR-NC group, the expression level of miR-199a in stretch + miR-199a group was significantly higher; while ALP activity, OCN, OSX, Runx2 mRNA and protein expression level, calcium nodule formation level were significantly lower(P<0.05). miR-199a could targetedly bind to IGF1, and the expression level of IGF1 mRNA and protein in MC3T3-E1 cells was significantly reduced by miR-199a mimic(P<0.05). CONCLUSIONS: MiR-199a can inhibit the osteogenic differentiation of MC3T3-E1 cells induced by mechanical stretch stimulation, and its mechanism may be related to the targeted regulation of IGF1 expression. References | Related Articles | Metrics

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Detection and analysis of dental dust concentration in the department of prosthodontics YANG Xiang-wen, ZHONG Qun, WANG Jue 2022, 31 (2):  138-141.  doi: 10.19439/j.sjos.2022.02.005 Abstract ( 342 )   PDF (540KB) ( 242 )   PURPOSE: To detect and analyze dental dust pollution in the department of prosthodontics and propose reasonable protective measures. METHODS: Individual dust sampling pumps were used to detect the concentration of respirable dust produced by five common dental materials (hard resin base, advanced artificial teeth, photosensitive plastic, cobalt-chromium alloy, veneering ceramics) in the department of prosthodontics. X-ray diffraction (XRD) was used to detect the concentration of free silica respirable dust in veneer porcelain dust. Inductively coupled atomic emission spectrometry (ICP-AES) was used to detect the thoracic dust of cobalt element and the inhalable dust concentration of chromium element in cobalt-chromium alloy dust. The results were compared with the occupational exposure limits set by China and the United States. RESULTS: The respiratory dust concentration of the five common dusts in the department of prosthodontics was far lower than occupational exposure limits set by China and the United States. The concentration of free silica in veneer porcelain, cobalt and its compounds in cobalt-chromium alloys were below the lower detection limit. Chromium and its compounds can be detected, and its concentration was also far below the occupational exposure limit. CONCLUSIONS: Problem of dust pollution in the department of prosthodontics exists, which is mainly caused by heavy metal pollution (such as chromium). Protective measures such as ventilation and wearing professional mask should be taken to protect the health of dental practitioners. References | Related Articles | Metrics

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LLY-283 inhibits proliferation and metastasis of head and neck squamous cell carcinoma by targeting PRMT5 CHEN Qi, XIE Fei, JI Ying-ying, WEI Kui-jie, REN Qiang 2022, 31 (2):  142-147.  doi: 10.19439/j.sjos.2022.02.006 Abstract ( 288 )   PDF (1633KB) ( 206 )   PURPOSE: To explore the effect of LLY-283 on the biological behavior of Head and neck squamous cell carcinoma(HNSCC) proliferation and metastasis through protein arginine methyltransferase 5(PRMT5). METHODS: TCGA database was used to analyze the expression level of PRMT5 in HNSCC tissues and cell lines by RT-PCR and Western blot. Lentiviral technology was used to construct PRMT5 knockdown stable cell line, and analyze the effect of PRMT5 on the biological behavior of HNSCC. Drug killing experiment was used to observe the IC50 changes of LLY-283 in cell lines. Nude mouse xenograft experiments were further tested to observe the biological effects of LLY-283 on HNSCC through PRMT5. RESULTS: PRMT5 was highly expressed in HNSCC tissues and cell lines, which promoted the proliferation and metastasis of cell lines, and reduced the IC50 value of LLY-283. LLY-283 could significantly reduce the cell proliferation and metastasis, tumor volume and Ki-67 expression in nude mice in vivo of HNSCC through PRMT5. CONCLUSIONS: LLY-283 inhibits the expression of PRMT5 and Ki-67, thereby decreases the proliferation and metastasis of HNSCC and the ability to form transplanted tumors in nude mice, exerting anti-tumor effects. References | Related Articles | Metrics

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Effect of chronic sleep deprivation on condylar cartilage in rats BAI Yue-hui, LIU Yang, CUI Yu-lan, JIANG Shan-shan, SHANG Qing-long, ZHAO Chen 2022, 31 (2):  148-155.  doi: 10.19439/j.sjos.2022.02.007 Abstract ( 262 )   PDF (2158KB) ( 187 )   PURPOSE: The aim of this study was to investigate the morphological changes of condylar cartilage of temporomandibular joint (TMJ) and the expression changes of IL-1β,TNF-α,IGF-1 and VEGF in condylar cartilage of TMJ by establishing a chronic sleep deprivation model in rats. METHODS: Sixty rats were randomly divided into experimental group, control group and recovery group. Modified multiple platforms method (MMPM) was used to build chronic sleep deprivation models in experimental and recovery groups. Rats in the recovery group received 1 week of cage feeding after sleep deprivation. H-E staining was used to observe morphological change of the condyle. Immunohistochemical method was performed to detect the changes of IL-1β, TNF-α, IGF-1 and VEGF. The data was processed by using SPSS 23.0 software package. RESULTS: MMPM can establish chronic sleep deprivation model effectively. H-E staining showed condylar cartilage of the experimental group was split stripped, and the boundaries of cartilage cell layer became blurred. Compared with the control group, the recovery group had less cracks in the fibrous layer or some of the cracks were occupied by fibrous tissue. Immunohistochemistry showed that the positive expression intensity of IL-1β and TNF-α in the experimental group was significantly higher than in the control group (P<0.05), the positive expression intensity in the recovery group was significantly lower than in the experimental group(P<0.05). The positive expression intensity of IGF-1 and VEGF in the experimental group was significantly higher than in the control group(P<0.05). The expression of IGF-1 and VEGF decreased significantly in the recovery group which received sleep deprivation no more than 3 weeks(P<0.05). CONCLUSIONS: Chronic sleep deprivation can increase the expression of IL-1β, TNF-α and VEGF in condylar cartilage and aggravate osteoarthritis. Chronic sleep deprivation can lead to increase of IGF-1 in condylar cartilage tissue, which plays a crucial role in protecting and promoting the reconstruction of condylar cartilage. After chronic sleep deprivation, the expressions of IL-1β, TNF-α, IGF-1 and VEGF in the condylar cartilage of rats were decreased after 1 week of recovery, and the condylar cartilage underwent restorative reconstruction. References | Related Articles | Metrics

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Effect of low-energy microwave irradiation on orthodontic tooth movement and periodontal tissue remodeling in rats LIU Wei-jia, TANG Zhen, ZHANG Qi, JIANG Li-ping 2022, 31 (2):  156-161.  doi: 10.19439/j.sjos.2022.02.008 Abstract ( 239 )   PDF (2176KB) ( 224 )   PURPOSE: To investigate the effect of low-energy microwave irradiation on the movement of orthodontic teeth and periodontal tissue reconstruction in rats. METHODS: SD rats were randomly divided into control group and experimental group. Helical spring force method was used to construct a rat orthodontic model through a nickel-titanium tension spring device. Rats in the experimental group were irradiated with a microwave treatment apparatus once a day to move the first molars for 30 minutes, while rats in the control group were not given any intervention. The rats were sacrificed on the day of modeling, 7 d, 14 d, and 21 d thereafter. The movement distance of the rat's first molars was measured. Tartrate-resistant acid phosphatase (TRAP) staining was used to detect osteoclast counts in rat periodontal tissues, immunohistochemistry was used to detect the expression of cell differentiation factor (osteoclast differentiation factor, ODF) in rat periodontal tissues; real-time fluorescence quantitative PCR(RT-PCR) was used to detect the mRNA expression of interleukin 6(IL-6) and tumor necrosis factor-α (TNF-α). SPSS 20.0 software package was used to analyze the experimental data. RESULTS: At 7, 14, 21 d, compared with the control group, the distance of the first molar movement, the count of osteoclasts in the periodontal tissue, and the expression of ODF in the experimental group were significantly increased (P<0.05), while the mRNA expression of IL-6 and TNF-α in periodontal tissues was significantly decreased (P<0.05). CONCLUSIONS: Low-energy microwave irradiation can significantly accelerate the movement of orthodontic teeth, inhibit the expression of inflammatory genes, and promote the reconstruction of periodontal tissue. References | Related Articles | Metrics

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Establishment of a 3-dimentional finite element system simulating En masse retraction implemented by customized lingual appliances XU Zi-qing, WANG Te, JIANG Jian-yu, SHEN Gang 2022, 31 (2):  162-166.  doi: 10.19439/j.sjos.2022.02.009 Abstract ( 323 )   PDF (1360KB) ( 217 )   PURPOSE: This study was designed to establish a 3-dimentional finite element system to simulate the clinical scenario where labial segment was retracted with sliding mechanism in extraction cases treated by individualized lingual orthodontics. METHODS: A typical clinical case was selected. The subject was diagnosed with Class I malocclusion with alveolar protrusion and treated with extraction of 4 first premolars. The subject was under the treatment stage of frontal retraction by eBrace system, an individualized lingual appliance. The subject was also taken cone-beam CT (CBCT) based on which digital 3D reconstruction of dentition structures was formed with Mimics software. With the aid of software platform Pro/E 4.0, the important anatomical structures were defined, and relevant lingual devices, including lingual brackets, arch-wires, mini-screws and other accessories were formed. With the aids of software platform Geomagic Studio 13.0, the 3-dimentional structural mode, featuring maxillary alveolar, upper dentition, periodontal ligament, miniscrew and lingual applicance, were constructed. With the assistance of Ansys Workbench 15.0, 3D model for finite element system was finalised by conducting model meshing and defining the mechanical properties and the interface relations of the selected materials. RESULTS: Based on the digital information drawn from CBCT image, a 3-dimentional finite element system was successfully created, featuring all the elements mimicking the clinical scenario for En masse retraction. This system enabled an insight study on the effects of various retraction modes controlling the incisal torque and maintaining the dental arch integrity. CONCLUSIONS: The creation of a finite element system in this study is based on the digital data from the CBCT image of a real patient diagnosed with prognathic malocclusion and treated by lingual appliance. The clinical scenario of labial segment retraction via sliding mechanism is simulated in this finite element model. References | Related Articles | Metrics

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Expression of TNFAIP6 in oral verrucous carcinoma and oral squamous cell carcinoma and its relationship with clinicopathology CHEN Juan, CAO Ruo-yan, LIU Yang, HONG Peng-yu, TANG Zhan-gui 2022, 31 (2):  167-172.  doi: 10.19439/j.sjos.2022.02.010 Abstract ( 237 )   PDF (1075KB) ( 193 )   PURPOSE: To investigate the expression of tumor necrosis factor α-induced protein 6 (TNFAIP6 ) in oral verrucous carcinoma(OVC）and oral squamous cell carcinoma(OSCC), and its relationship with clinicopathology. METHODS: RNA-seq data of OSCC was downloaded from the TCGA database. Paired t test was used to compare the expression of TNFAIP6 from OSCC and normal oral mucosa. Receiver operating characteristic curve(ROC) and Kaplan-Meier curve were drawn to evaluate its diagnostic and prognostic value, respectively. Fifteen cases of normal oral mucosa （NM）, 22 cases of OVC and 24 cases of OSCC paraffin specimens were used for TNFAIP6 detection by immunohistochemistry; furthermore, the relationships between the positive expression rate and clinical factors was analyzed. Five pairs of OSCC cancer and adjacent tissues, 5 pairs of OVC cancer and adjacent tissues were verified by reverse transcription polymerase chain reaction and Western blotting. The measurement data was analyzed using Graph Pad Prism 7.0 software, and paired t test was used for comparison between groups with SPSS 21.0 software package. RESULTS: In the TCGA database, the expression of TNFAIP6 was significantly up-regulated in OSCC and had certain diagnostic value. The expression of TNFAIP6 in OSCC paraffin specimens was significantly up-regulated, which was related to alcohol consumption, cervical lymph node metastasis and clinical stage. The expression of TNFAIP6 in OVC paraffin specimens was significantly up-regulated, which was related to the size of the primary tumor. TNFAIP6 was significantly up-regulated in transcription and protein expression in OSCC tumor tissues. All the above results were statistically significant(P<0.05). CONCLUSIONS: TNFAIP6 is highly expressed in OSCC tissues and associated with diagnosis and prognosis, which can be used as a molecular marker for OSCC. References | Related Articles | Metrics

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Periodontal health survey and analysis of influencing factors in 916 patients with type 2 diabetes DING Yuan-sen, SHAO Zheng-wei, LIN Zong-jian, ZOU De-rong 2022, 31 (2):  173-177.  doi: 10.19439/j.sjos.2022.02.011 Abstract ( 270 )   PDF (648KB) ( 186 )   PURPOSE: To investigate the periodontal health status of type 2 diabetes patients in the Endocrinology Department of Shanghai Sixth People's Hospital, to explore relevant influencing factors of chronic periodontitis, so as to provide epidemiological basis for targeted prevention and treatment of periodontal diseases in patients with type 2 diabetes. METHODS: Periodontal examination and questionnaire survey of patients with type 2 diabetes who visited the Endocrinology Department of Shanghai Sixth People's Hospital from November 2018 to December 2018 were conducted. Criteria in "Basic Methods for Oral Health Survey" recommended by WHO was referred to check and score the relevant periodontal indicators, including probing depth, bleeding on probing, attachment loss, calculus index, plaque index, etc. Sociodemographic information, diabetes history, periodontal health-related behaviors, and other information were collected through questionnaires. SPSS 22.0 software package was used for statistical analysis. RESULTS: Of the 916 patients with type 2 diabetes who participated in the survey, 670 patients with periodontitis were detected. The overall prevalence of periodontitis was 73.14%, and the number of missing teeth per capita was 4.85. The age of diabetic patients, the duration of diabetes, and the presence or absence of complications were risk factors for periodontitis. As the patients grew, the duration of the disease increased, and diabetes-related complications appeared, the prevalence of periodontitis in patients with diabetes increased significantly (P<0.05). CONCLUSIONS: Periodontal health of patients with type 2 diabetes in the surveyed region is not optimistic. Early prevention and treatment of periodontitis is extremely important. It is necessary to pay attention to the periodontal health status of elderly patients with long-term disease and diabetes, and to carry out targeted oral prevention and health care work for this population. References | Related Articles | Metrics

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Expression of B cell activation factor and correlation analysis in patients of systemic lupus erythematosus and its correlation with periodontitis ZHANG Li-mu, WANG Ye, QI Shuai, LIN Xiao-ping 2022, 31 (2):  178-183.  doi: 10.19439/j.sjos.2022.02.012 Abstract ( 256 )   PDF (621KB) ( 145 )   PURPOSE: To detect the level of B cell activating factor (B - cell activating factor of the TNF family, BAFF) in the serum of patientes suffering from systemic lupus erythematosus (SLE) with periodontitis, and analyze the relationship between the expression of BAFF with periodontitis and SLE. METHODS: According to the inclusion criteria, patients visiting the Department of Stomatology and Rheumatology, Shengjing Hospital Affiliated to China Medical University were selected, including 19 patients in the periodontitis group(P group), 22 in the systemic lupus erythematosus group (SLE group), 24 in the systemic lupus erythematosus combined with periodontitis group(SLE+P group), and 20 in the healthy control group(H group). The general information, periodontal probing depth (PD), clinical attachment loss (CAL), gingival sulcus bleeding index(SBI) were collected. Serum samples of patients in each group were collected, and BAFF content was determined by Elisa. Rheumatic and immunological indexes of subjects in SLE group and SLE+P group were determined, and the correlation between BAFF content and periodontal indexes was analyzed. SPSS 20.0 software package was used for statistical analysis. RESULTS: CAL in P+SLE group was significantly higher than that in P group(P<0.05). Serum BAFF concentrations in SLE+P group, SLE group and P group were significantly higher than those in the healthy control group (P<0.05). Serum BAFF concentration in SLE+P group was significantly higher than that in SLE group(P<0.05). ESR, SLEDAI and disease duration in SLE+P group were significantly higher than those in SLE group (P<0.05). The expression level of BAFF in serum was positively correlated with CAL and SBI(P<0.01). The expression level of BAFF in serum was positively correlated with PD(P<0.05). There was significant positive correlation between serum BAFF level and duration of disease and hormone use(P<0.01). Serum BAFF level was positively correlated with C3 (P<0.05). CONCLUSIONS: SLE has certain correlation with periodontitis, and serum BAFF in SLE patients with periodontitis is significantly increased.BAFF may be associated with the development of SLE and periodontitis. References | Related Articles | Metrics

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Effect of invisible appliance without bracket and self-locking bracket appliance on periodontal and subgingival flora in patients with periodontitis ZHU Yong-cui, ZHU Feng-jie, ZHAI Lei, CUI Shu-xia 2022, 31 (2):  184-188.  doi: 10.19439/j.sjos.2022.02.013 Abstract ( 318 )   PDF (744KB) ( 255 )   PURPOSE: To observe the effect of non-bracket invisible appliance and self-locking bracket appliance on periodontal health and subgingival flora in patients with periodontitis. METHODS: One hundred and ten patients with periodontitis who received orthodontic treatment were divided into invisible group and self-locking bracket group. The periodontal index including probing depth (PD), gingival index (GI), sulcular bleeding index (SBI) and plaque index (PLI) ,and the levels of inflammatory factors in the gingival crevicular fluid were examined. Visual analogue scale (VAS) was used to evaluate periodontal pain before and after correction, and the curative effect was evaluated. The status of common pathogenic bacteria in the subgingival plaque of patients after correction was detected by PCR. The data were analyzed with SPSS19.0 software package. RESULTS: Twelve months after treatment and at the end of treatment, PLI of the self-locking bracket group was significantly higher than the invisible group(P<0.05), but PD, GI and SBI between the two groups had no significant difference. After correction, the inflammatory factors in the invisible group were significantly lower than those in the self-locking bracket group(P<0.05). At 1d after treatment, pain index in the invisible group was significantly lower than the self-locking group(P<0.05). The clinical total effective rate of the invisible group was significantly higher than the self-locking group (89.10% vs 76.36%). After treatment, the detection rate and the content of subgingival pathogenic bacteria in the self-locking bracket group were significantly higher than the invisible group(P<0.05). CONCLUSIONS: During orthodontic treatment of periodontitis, wearing non-bracket invisible appliance can effectively inhibit inflammatory response and proliferation of subgingival pathogens, which is more conducive to the maintenance of periodontal health and oral hygiene. References | Related Articles | Metrics

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The effect of four immunosuppressive drugs on oral manifestations after organ transplantation ZHAO Wen-jiao, JIN Ya-feng, LYU Ke-jia, YAN Duo-duo, YAO Hua 2022, 31 (2):  189-192.  doi: 10.19439/j.sjos.2022.02.014 Abstract ( 348 )   PDF (581KB) ( 194 )   PURPOSE: To assess the prevalence of oral manifestations in a group of allogenic liver, kidney or haematopoietic stem cell transplantation recipients and patients, and analyze the possible oral manifestations associated with the use of 4 immunosuppressive drugs. METHODS: One hundred and eighteen patients submitted to liver, kidney and hematopoietic stem cell transplantation who used tacrolimus, sirolimus,cyclosporine or mycophenolate mofetil were enrolled. Through a questionnaire survey and oral examination, their oral manifestations were recorded, and the possible statistical associations with immunosuppressive drugs were analyzed using SPSS 21.0 software package. RESULTS: The prevalence of oral lichenoid lesions and cheilitis for the group of patients using tacrolimus after transplantation was significantly lower than the group of patients who did not used the agent(P<0.01). The prevalence of oral lichenoid lesions for the group of patients who used cyclosporine was significantly higher than the group of patients who did not used the drug(P<0.05), and the prevalence of cheilitis for the group of patients who used cyclosporine was significantly higher than the group of patients who did not used the drug(P<0.01). The prevalence of oral lichenoid lesions and cheilitis for the group of patients who used tacrolimus was significantly lower than the group of patients who used cyclosporine(P<0.01). The group of patients who used mycophenolate mofetil after transplantation had a significantly lower prevalence of dry mouth than the group of patients who did not used the drug(P<0.01). The prevalence of oral manifestations in patients with sirolimus after transplantation was not significantly reduced. CONCLUSIONS: The use of tacrolimus improved the symptoms of oral lichenoid lesions and cheilitis and the effect was better than cyclosporine after transplantation. The use of mycophenolate mofetil improved dry mouth after organ transplantation. References | Related Articles | Metrics

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Clinical efficacy of the combination of miniscrew with clear aligner in controlling the roller coaster effect MA Xiao-qing, XIANG Fei, FAN Ming-yue, SONG Yi, WANG Xiao-hui, ZHANG Ling, QIAN Wen-hao 2022, 31 (2):  193-197.  doi: 10.19439/j.sjos.2022.02.015 Abstract ( 563 )   PDF (1173KB) ( 383 )   PURPOSE: To investigate the clinical efficacy of miniscrew in controlling the roller coaster effect in long-distance space closure with clear aligner. METHODS: Sixteen adult patients with bimaxillary protrusion were selected. All cases were treated with clear aligner and their four first premolars were extracted. G6 was designed in all cases. In the experimental group, four miniscrews were inserted at the beginning of treatment to control the teeth in three dimensions; while in the control group, the miniscrews were not applied until obvious roller coaster effect appeared. Paired t test was used to analyze the data with Graphpad Prism 6.0 software package. RESULTS: All the extraction space was closed successfully and the lateral profile was improved significantly. The torque of the upper incisor was under well control and no roller coaster effect happened in the experimental group; while in the control group, the lingual inclination of the upper incisors and open bite of the posterior teeth developed(P<0.05). After the miniscrews intrusion of the upper anterior teeth, the occlusion relationship improved significantly. CONCLUSIONS: Miniscrews effectively prevents and eliminates the roller coaster effect in the process of long-distance space closure with clear aligner. References | Related Articles | Metrics

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The influence of different preparation methods on interappointment emergency and filling effect of root canal therapy HU Yuan-ping, QIAN Yi 2022, 31 (2):  198-200.  doi: 10.19439/j.sjos.2022.02.016 Abstract ( 257 )   PDF (398KB) ( 172 )   PURPOSE: To compare the effect of different root canal preparation methods on the incidence of interappointment emergencies (IAE) and root canal filling. METHODS: A total of 96 teeth requiring root canal therapy due to pulpitis or periapical periodontitis from August 2018 to August 2021 were selected. They were randomly divided into 2 groups: MT group was treated with Mtwo root canal preparation method modified by Mtwo machine nickel-titanium file, while synchronous group was treated with modified Mtwo preparation method and synchronous root canal length measurement. After root canal preparation, the trial point film was taken, calcium hydroxide was used to seal the root canal, and routine thermoplasticizied gutta-percha root canal filling was performed during the follow-up visit. SPSS 22.0 software package was used to analyze the incidence of IAE and filling effect after root canal therapy. RESULTS: There was no significant difference in the incidence of IAE between the two groups immediately after operation, three days and 1 week after operation(P>0.05); the incidence of IAE in synchronous group was significantly lower than that in MT group at 1 and 2 days after operation(P<0.05). The qualified rate of root canal filling in synchronous group was significantly higher than that in MT group (P<0.05). CONCLUSIONS: Synchronous method can reduce mechanical stimulation of apical area during root canal preparation, strictly control the working length of root canal and maintain apical barrier, thus reducing the incidence of IAE and effectively improving the qualification rate of root canal filling. References | Related Articles | Metrics

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Analysis of microbial diversity in supragingival plaque and caries tissue of patients with different dental caries phenotypes WANG Shi-wei, YANG Jian-jun, ZHANG Song-zi 2022, 31 (2):  201-204.  doi: 10.19439/j.sjos.2022.02.017 Abstract ( 245 )   PDF (1056KB) ( 195 )   PURPOSE: To identify the microbial characteristics and diversity in supragingival plaque and caries tissue of patients with different dental caries phenotypes. METHODS: From January 2019 to December 2019, randomized double-blind method was used to select 10 healthy people without caries and 33 patients with caries of mild, moderate and severe degrees in dental clinic of our hospital. Supragingival plaque and caries tissues were collected, and detected by pyrosequencing through amplification of the 16S rRNA-cDNA hypervariable regions. Then the microbial species and relative abundance were compared among patients with different severity degrees. SPSS 23.0 software package was used to analyze the data. RESULTS: Compared with non-caries group, the content and abundance of microorganisms in supragingival plaque and carious tissue of caries group were significantly decreased (P<0.05). The main caries tissue of three severity degree groups were dominated by Bacteroidetes, Spirochaetes, Proteobacteria, Fusobacteria, Firmicutes and Actinobacteria, and the proportion of the predominant bacteria had significant difference among three groups(P<0.05). There were 21 species of supragingival bacteria in three groups, among which Fusobacteriales, Coriobacteriales, Neisseriales, Actinomycetales and Lactobacillales accounted for a high proportion, and the remainings were all below 1%, while the proportion of five main bacteria showed no significant difference among three groups (P>0.05). CONCLUSIONS: Caries is caused by a variety of bacteria, and is the result of microbial communities rather than a single pathogen; Moreover, the microbial abundance of plaque and caries tissue vary among patients with different dental caries phenotypes, and the microbial diversity has a decreasing trend in the progress of dental caries. References | Related Articles | Metrics

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Influencing factors of nutritional status and change in 50 patients with oral squamous cell carcinoma during treatment MAIERHABA·Maihemuti, BAI Jie, RUSITANMU·Yimiti, YAO Zhi-tao 2022, 31 (2):  205-210.  doi: 10.19439/j.sjos.2022.02.018 Abstract ( 263 )   PDF (723KB) ( 172 )   PURPOSE: To investigate the changes of nutritional status in patients with oral squamous cell carcinoma(OSCC) and analyze the influencing factors during treatment. METHODS: Anthropometry (weight, BMI, waistline, middle circumference of left and right upper arms) and laboratory index(serum prealbumin, serum albumin, transferrins, 25-hydroxyvitamin D) were measured to represent the nutritional status of 50 patients with OSCC before operation, two days, one month and three months after operation. SPSS 24.0 software package was used for statistical analysis of the data, and influencing factors of nutrition risk in OSCC patient were analyzed with binary logistic regression model. RESULTS: Univariate and multivariate analysis showed that advanced age(OR=1.127,95%CI: 1.053-1.207), low educational level (OR=5.250, 95%CI: 1.147-21.796), smoking(OR=6.182, 95%CI: 1.631-23.433), alcohol use(OR=5.227, 95%CI: 1.336-20.450), chemoradiotherapy (OR=3.984, 95%CI: 1.199-13.242), free flap surgery (OR=8.000, 95%CI: 2.060-31.068), tracheostomy(OR=3.960, 95%CI: 1.069-14.671), cervical lymph node metastasis(OR=4.821, 95%CI: 1.418-16.399), buccal carcinoma(OR=9.000, 95%CI:1.140-71.038), tongue cancer(OR=7.200, 95%CI: 1.081-47.962), tumor stage T3-4(OR=3.542, 95%CI: 1.066-11.771) were independent influencing factors of the nutritional status of patients with OSCC. CONCLUSIONS: Aging, low educational level, smoking history and drinking history in the general demographic characteristics of patients, and chemoradiotherapy, free flap surgery, tracheostomy during treatment, as well as buccal carcinoma, tongue cancer, advanced stage and cervical lymph node metastasis are clinical characteristics, which affect the nutrition level during the treatment for OSCC patients. References | Related Articles | Metrics

Clinical Reports

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Cone-beam CT measurement of morphological changes of the root and alveolar bone of the central incisor during orthodontic treatment with extraction LIN Yi-jun, YAN Jie-ya, WANG Tian-ge, ZHOU Zhi-jie, LIAO Sheng-hsuan, MAO Li-xia, LIU Jia-qiang 2022, 31 (2):  211-216.  doi: 10.19439/j.sjos.2022.02.019 Abstract ( 355 )   PDF (902KB) ( 176 )   PURPOSE: To study the effect of orthodontic treatment with extraction on root resorption and alveolar bone morphology of the central incisor in adult patients. METHODS: Eleven adult patients receiving orthodontic treatment were enrolled, and asked to take cone-beam CT(CBCT) scanning before and after treatment. Root resorption of the upper and lower central incisors after treatment, changes in alveolar bone thickness and height of alveolar bone were measured and compared. Statistical analysis was performed using SPSS 23.0 software package. RESULTS: The length of the tooth and root was reduced to a certain degree. The change in root length of the maxillary incisor was larger than that of the mandibular incisor. The alveolar bone width of the lingual and palatal neck of the central incisor showed some reduction, and alveolar bone width of the palatal neck of the upper central incisor and the middle lingual side of the mandibular central incisor changed to a certain extent. The width of the alveolar bone in the middle labial side of the mandibular central incisor increased, but the alveolar bone on the lingual and palatal side increased after orthodontic treatment, which was more obvious than that of the maxillary central incisor. CONCLUSIONS: Orthodontic treatment with tooth extraction is accompanied by a certain degree of root resorption of the central incisor and alveolar bone on the lingual and palatal side. However it is also accompanied by an increase in the amount of alveolar bone on the labial side. More fenestration and dehiscence are observed in the mandible. References | Related Articles | Metrics

Dental Education

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Application of Wechat public platform in teaching reform of prosthodontics CHEN Jian-zhi, LIN Wei-wei, SHI Yue-hua 2022, 31 (2):  217-220.  doi: 10.19439/j.sjos.2022.02.020 Abstract ( 316 )   PDF (773KB) ( 233 )   PURPOSE: To explore the law of development and existing problems in prosthodontics teaching in the new era, through flipped classroom teaching based on WeChat public platform. METHODS: WeChat public number was applied and WeChat groups were set up among the students of grade 2013, and 93 students were divided into 20 WeChat groups, with 4 to 5 students in each group. The main platform on reform of prosthodontics teaching was WeChat app, supplemented by platforms of Lediaocha and Youkaoshi. Teachers published courseware and learning resources with WeChat public number and WeChat groups. Two-dimensional codes on questionnaires and tests which were generated by Lediaocha and Youkaoshi could be published with WeChat and the final learning effectiveness was compared using SPSS 19.0 software package for t test. RESULTS: The results showed that 59.1% students admitted WeChat teaching effective, only 5.4% students believed ineffective. Based upon partial chapters of prosthodontics, the score of classroom test (91.35±4.45) was significantly higher than that of pre-class test(90.14±5.03, P<0.05). CONCLUSIONS: The reform of flipped classroom based on WeChat platform in prosthodontics have some advantages, such as more flexibility in teaching form and time arrangement, promoting students' learner autonomy, and increasing students' motivation and effects of learning prosthodontics. References | Related Articles | Metrics

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Application of CAD in custom tray design for teaching of dental postgraduates WANG Can, XIE Pei-jin, WU Jun-hua, SU Jian-sheng 2022, 31 (2):  221-224.  doi: 10.19439/j.sjos.2022.02.021 Abstract ( 214 )   PDF (563KB) ( 246 )   PURPOSE: To evaluate the teaching effect of making custom trays via CAD in dental postgraduates. METHODS: Twenty-seven dental postgraduates from first to third grade at the School & Hospital of Stomatology, Tongji University, Shanghai were given an informed consent to explain and request participation in the study. First, a lecture about the theory and process of fabricating custom tray via traditional hand-made method and CAD technique was given, then the students fabricated custom trays via the two methods and completed an online survey. The working time, margin extension and students' preference were analyzed with SPSS 22.0 software package. RESULTS: The working time was shorter, the margin extension was superior, and students' preference was higher via CAD than traditional method, the difference was significant(P<0.05). CONCLUSIONS: CAD is more conducive to enhance students' understanding of custom tray manufacturing process and relevant theoretical knowledge. It is recommended to integrate digital technology into dental curriculum. References | Related Articles | Metrics