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25 February 2021, Volume 30 Issue 1 Previous Issue    Next Issue

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Classification for mandibular deviation and facial asymmetry and its clinical significance SHEN Gang 2021, 30 (1):  1-6.  doi: 10.19439/j.sjos.2021.01.001 Abstract ( 1255 )   PDF (4956KB) ( 923 )   Judged from the clinical manifestations, etiological mechanisms and jaw morphological structures, malocclusions with mandibular deviation and facial asymmetry are classified into three main categories, i.e., those with mandibular positioning factors, those with mandibular condyle defects, and those with jaw congenital deformities. In the first category, three subtypes, including mandibular rotation caused by dentitional irregularities, by dental compensation and by habitual posturing, are further defined. In the second category, mandibular deviation caused by condylar asymmetrical resorption or hyperplasia are defined as the two subtypes. The third category is further divided into two subtypes, i.e., jaw and facial asymmetry resulting from maxillary or mandibular structural deformities. The prime goal of orthodontic therapy is to displace and restore the deviated mandible to its right position, followed by correction of occlusal intercuspation. As an important procedure of the whole treatment protocol, It is critical to detect and localize the correct mandibular position by manipulation and then register it by wax pattern and articulator transferring. For the cases with mandibular functional elements and condylar asymmetrical length, the treatment modalities include orthopedic repositioning of the mandible by using occlusal and bite plane, SGTB and SGHB therapies; for cases with growth and developmental anomalies, orthognathic intervention should be an optimal solution. References | Related Articles | Metrics

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Comparison of fracture strength of two chairside CAD/CAM ceramic blocs with different thickness LIN Chen-guan-lu, HU Xiao-kun, YAN Yu-xin, QU Yan-hui, LIU Mei, ZHANG Fei-min 2021, 30 (1):  7-12.  doi: 10.19439/j.sjos.2021.01.002 Abstract ( 312 )   PDF (4683KB) ( 250 )   PURPOSE: To provide theoretical basis for clinical CAD/CAM restorations with a comparison of the fracture strength between two chairside CAD/CAM immediate restorative materials (IPS e.max CAD and Vita Enamic) with different occlusal thickness in vitro. METHODS: IPS e.max CAD and Vita Enamic full-crowns with occlusal thicknesses 1.5/2.0/2.5 mm were fabricated with CEREC and adhesively seated to dies customized by manufacturer (n=42). All specimens were stored in distilled water at 37 ℃ for 24 h. Later, static fractural loading was performed. The fracture surface was observed through scanning electron microscope (SEM) and energy dispersive spectrum (EDS). The composites of two materials were detected by X-Ray diffraction (XRD) techniques. The results of fracture strength were analyzed by one-way ANOVA and t-test via SPSS 20.0 software package. RESULTS: With the increase of occlusal thickness, the fracture strength of IPS e.max CAD increased remarkably. However, the Vita Enamic's fracture strength remained the same with no significant difference. With the occlusal thickness increased from 1.5 to 2.0 mm, there was no significant difference in the fracture strength between IPS e.max CAD group and Vita Enamic group. As the thickness increased from 1.5 to 2.0 mm, the fracture strength of IPS e.max CAD group was significantly higher than that of Vita Enamic group. The results of SEM showed that the filler particles of IPS e.max CAD were smaller compared to that of Vita Enamic. Cone cracks were mainly found in the fracture surface of IPS e.max CAD, while radical cracks appeared in Vita Enamic. EDS showed the metal oxide and SiO2 in Vita Enmic was significantly higher than that in IPS e.max CAD. XRD showed that the primary crystal phase of IPS e.max CAD was lithium silicate, while Vita Enamic was amorphous. CONCLUSIONS: Both IPS e.max CAD and Vita Enamic can meet the standard of clinical application as the occlusal thickness reaches 1.5 mm. IPS e.max CAD showed better fracture resistance when the thickness was greater than 2.0 mm. References | Related Articles | Metrics

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Expression of hypoxia inducible factor-1alpha during mouse mandibular first molar eruption and its significance HU Xiu, KANG Fei-wu 2021, 30 (1):  13-16.  doi: 10.19439/j.sjos.2021.01.003 Abstract ( 217 )   PDF (3188KB) ( 169 )   PURPOSE: To investigate the expression of hypoxia inducible factor-1alpha (HIF-1α) during the eruption of mouse lower first molar, and to explore the correlation between its expression and the activity of osteoclasts. METHODS: Mouse mandibles were dissected from mice at day 1.5 to 14.5 after birth. They were then serially sectioned and stained respectively using hemotoxylin, tartrate-resistant acid phosphatase (TRAP) staining, and immunohistochemical staining. SPSS 25.0 software package was used for data analysis. RESULTS: During the eruption of mouse lower first molar, the thickness of the crown alveolar bone gradually decreased, so did the number of osteoclasts and the expression of HIF-1α. CONCLUSIONS: During the eruption of mouse lower first molar, the less expression of HIF-1α, the fewer osteoclasts there were. HIF-1α may be involved in the eruption of mouse lower first molar by regulating the activity of osteoclasts. References | Related Articles | Metrics

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The effect of low-magnitude high-frequency loading on peri-implant bone healing and implant osseointegration in Beagle dogs WANG Shu-hua, SUN Zhe, LI Hui, YE Xin-jian, ZHENG Sheng, FENG Jian-ying 2021, 30 (1):  17-22.  doi: 10.19439/j.sjos.2021.01.004 Abstract ( 229 )   PDF (4710KB) ( 210 )   PURPOSE: Low-magnitude, high-frequency（LMHF） loading has been confirmed to play an important role in bone healing. The present study aimed to evaluate the effect of LMHF loading applied directly to titanium dental implants on peri-implant bone healing and implant. METHODS: The mandibular premolars and molars were extracted from six male Beagle dogs. Three months post-extraction, six titanium implants (Aadva Standard Implant Narrow, 3.3 mm×8 mm) were inserted into the mandibular premolar and molar area (three implants per side) in each of the six dogs. In each animal, one side was randomly selected to undergo daily LMHF loading (experimental group), while the other side had no further intervention (control group). The loading was applied directly to the implant abutment using an individual jig and a custom-made loading device (8 μm,100 Hz). The implant stability quotient (ISQ) was tested every week. Three dogs were euthanized after 2 weeks, and three were euthanized after 8 weeks. Tissue samples were fixed and stained for micro-computed tomography(micro-CT) and histomorphometric analyses. The data were statistically analyzed using SPSS 13.0 software package. RESULTS: The experimental group had significantly increased peri-implant bone volume relative to tissue volume in region of interest 2 (100-500 μm) compared with the control group after 2 weeks of loading (P<0.05); however, there was no significant difference between the two groups after 8 weeks (P>0.05). The ISQ value and the micro-CT results did not differ between the two groups during the study period. CONCLUSIONS: LMHF loading positively influences peri-implant bone healing and osseointegration in the early healing period. References | Related Articles | Metrics

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Effect of ipriflavone on reconstruction of periodontal tissues during recurrence of orthodontic teeth in rats DAI Shu-lin, WANG Xu-xia, NIE Fu-jiao, CUI Qun, HAN Yuan-yuan, ZHANG Jun 2021, 30 (1):  23-27.  doi: 10.19439/j.sjos.2021.01.005 Abstract ( 241 )   PDF (4194KB) ( 144 )   PURPOSE: To investigate the effect of ipriflavone on reconstruction of periodontal tissues during recurrence of orthodontic teeth. METHODS: Twenty-four male SD rats were randomized into 2 groups, ipriflavone group(IP group) and control group, there were 12 rats in each group. The model of recurrence after movement of orthodontic teeth in rats was established. After continuous loading for 10 days, the loading devices were removed. Rats in ipriflavone group (IP group) were given ipriflavone intragastrically for 10 mg/(kg·d) after the devices were removed, while rats in the control group were given an equivalent amount of normal saline after the devices were removed. On the 0th, 1st, 3rd, 7th, and 10th day of administration, the rat maxillary impression and plaster model of two groups were prepared under local anesthesia, the distance between maxillary first molar lingual sulcus point and third molar in lingual groove point was measured to evaluate the relapse distance. After drug infusion for 10 days, the collected tissue specimens were stained with H-E to observe periodontal reconstruction, and expression of bone morphogenetic protein-2(BMP-2) was detected by immunohistochemical staining. Software Image-Pro 6.0 was used to analyze the optical density values of the stained sections. The data were analyzed with SPSS 22.0 software package. RESULTS: After removing the orthopaedic devices for 10 days , there was a significant recurrence of the movement of the orthodontic teeth in both groups. The recurrent distance of IP group was significantly smaller than that of the control group, and still significantly smaller than that of the control group at 10 d. H-E staining and immunohistochemical staining results showed that the IP group had more new bone formation and more BMP-2 expression in the periodontal tissues compared to the control group in vivo. CONCLUSIONS: In the process of recurrence of orthodontic tooth movement, ipriflavone can promote the expression of BMP-2 in periodontal tissue, improve bone remodeling of periodontal tissue, and effectively reduce the recurrent rate of orthodontic tooth movement. References | Related Articles | Metrics

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Evaluation of the effect of 3D printed HAP-GEL scaffold combined with BMSCs and HUVECs in repairing rabbit skull defect WANG Hong, FAN Hai-xia, CHENG Huan-zhi, LI Ran, GUO Xiu-juan, GENG Hai-xia 2021, 30 (1):  28-32.  doi: 10.19439/j.sjos.2021.01.006 Abstract ( 261 )   PDF (3850KB) ( 172 )   PURPOSE: To qualitatively analyze the effect of 3D printed hydroxyapatite-gel (HAP-GEL) scaffold combined with bone marrow mesenchymal stem cells (BMSCs) and human umbilical vein endothelial cells (HUVECs) in repairing rabbit skull defect. METHODS: The third generation BMSCs and HUVECs were co-cultured with 3D printed HAP-GEL scaffold to construct tissue engineering bone. The rabbit model of skull defect was established and randomly divided into 4 groups. HAP-GEL stent, HAP-GEL stent + BMSCs and HUVECs cells were implanted respectively, and positive control (autologous bone tissue) and blank control were set up. Twelve weeks after operation, X-ray, cone-beam CT (CBCT) scan and H-E staining were performed to observe and analyze the changes of bone defect qualitatively. RESULTS: Twelve weeks after operation, imaging examination (X-ray and CBCT) showed that there was still obvious circular transmission in the blank control group, and the density was increased and the defect boundary was blurred in both HAP-GEL stent combined cell group and HAP-GEL group, among which the bone was continuous and the bone mineral density was the highest in HAP-GEL stent composite cell group, which was close to normal tissue. The results of H-E staining at twelve weeks showed that compared with the blank control group and the HAP-GEL group, the defect area of the HAP-GEL composite group was filled with new bone and bone-like tissue, the scaffold material was degraded and there was new bone formation inside the scaffold, and the bone repair effect was good, and the osteogenic effect was similar to that of the positive control group. CONCLUSIONS: 3D printed HAP-GEL scaffold + BMSCs + HUVECs cell complex has good osteogenic ability and biocompatibility with a good effect on repairing rabbit skull defect. References | Related Articles | Metrics

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Inhibitory effects of theaflavin on planktonic and sessile bacterial cells of Streptococcus mutans in vitro ZHENG Pei, ZHANG Yu, WANG Sa 2021, 30 (1):  33-37.  doi: 10.19439/j.sjos.2021.01.007 Abstract ( 259 )   PDF (4026KB) ( 236 )   PURPOSE: Inhibitory effects of theaflavin(TF) on planktonic and sessile bacterial cells of Streptococcus mutans were investigated in the present study. METHODS: MIC and MBC of TF/EGCG/CHX on S. mutans UA159 were determined. Furthermore, biofilms were formed and treated with agents, then proliferative activity and viability of bacterial cells were detected. SPSS 22.0 software package was used for statistical analysis. RESULTS: TF was found to inhibit planktonic cells of S. mutans UA159 with MIC of 500 μg/mL and MBC of 1 mg/mL. Moreover, bacterial cells of S. mutans UA159 in the biofilms treated with TF at concentrations higher than 2 × MIC had lower proliferative activity and viability than those in control-treated biofilms. CONCLUSIONS: TF efficiently suppressed proliferative activity and viability of S. mutans biofilms, which provided theoretical basis for clinic applications of TF. References | Related Articles | Metrics

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Experimental study on the effect of tooth movement with thin and thick aligners in rabbits LI Guang-hui, PAN Xiao-gang 2021, 30 (1):  38-43.  doi: 10.19439/j.sjos.2021.01.008 Abstract ( 399 )   PDF (4668KB) ( 220 )   PURPOSE: To explore the effect of tooth movement on lower incisors of rabbits with thin and thick aligners. METHODS: A group of 6 male New Zealand rabbits were randomly divided into 2 groups, the experimental group(n=3) was designed to move the lower incisors distally by 3 steps with thin and thick aligners(0.625 and 0.75 mm),0.33 mm each;the control group (n=3) was designed to move the teeth by 3 steps with aligner of conventional thickness (0.75 mm), 0.20 mm each. Polyvinyl siloxane impressions were taken before and after aligner placement. The data of tooth movement were measured. SPSS 19.0 software package was used for statistical analysis. RESULTS: The accuracy of tooth movement expression in both groups decreased gradually from the incisal part to the gingival part. The rate of tooth movement in the experimental group was significantly higher than that of the control group（P<0.001）. CONCLUSIONS: The tooth movement of rabbit mandibular central incisor was tipping with the clear aligner. The rate of tooth movement was increased by applying thin and thick aligners,but the accuracy of tooth movement was decreased. References | Related Articles | Metrics

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MiR-99a inhibits proliferation of oral squamous cell carcinoma by targeting mTOR pathway WANG Ke, PENG Guo-guang, TAN Yu-lian, HE Shan-zhi, LUO Cui-fen 2021, 30 (1):  44-49.  doi: 10.19439/j.sjos.2021.01.009 Abstract ( 203 )   PDF (4754KB) ( 194 )   PURPOSE: To investigate miR-99a expression and its effect on proliferation of oral squamous cell carcinoma (OSCC). METHODS: miRNA microarrays associated with OSCC were identified in GEO database. The expression levels of miR-99a were detected in 63 OSCC tissues and adjacent normal tissues and cell lines. The relationship between clinicopathological parameters and miR-99a expression was analyzed by using ANOVA analysis. The ability of cell growth and clone formation were examined in SCC9 and SCC25 cells transfected with miR-99a mimics. The target genes of miR-99a were predicted by Targetscan software. There resulting data were analyzed using SPSS 19.0 software package.RESULTS: The differently expressed miRNAs were analyzed based on GSE103931 microarray. miR-99a was significantly downregulated in OSCC tissues and cell lines. miR-99a expression was significantly associated with T stage, pathological grading and patients’ prognosis. miR-99a overexpression inhibited OSCC cell proliferation and clone formation, while miR-99a inhibition contributed to decreased proliferation and clone formation ability. In addition, miR-99a combined with mTOR gene’s 3’UTR was negatively correlated with mTOR expression in OSCC tissues. CONCLUSIONS: miR-99a functions as a tumor suppressor in OSCC and inhibits OSCC cell proliferation by targeting mTOR. References | Related Articles | Metrics

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Adsorption behavior of low density lipoprotein on titanium surface XU Li-na, YU Ying-juan, SUN Jian 2021, 30 (1):  50-54.  doi: 10.19439/j.sjos.2021.01.010 Abstract ( 240 )   PDF (3673KB) ( 140 )   PURPOSE: The purpose of this study was to investigate the adsorption of low density lipoprotein (LDL) on titanium surface. METHODS: Pure titanium specimens were soaked with different concentrations of LDL (0, 1, 2 mg/mL). Low density lipoprotein essay was used to analyze the change of LDL adsorption on titanium surface with time going on. Scanning electron microscope(SEM) and X-ray photoelectron spectroscopy(XPS) were used to observe and analyze the adsorption of LDL on titanium surface and its effect on element composition of titanium surface. Contact angle of titanium surface was detected before and after LDL adsorption. SPSS 22.0 software package was used for statistical analysis of the data. RESULTS: The adsorption amount of LDL on titanium surface gradually increased as time went on. XPS analysis results showed that LDL was adsorbed on the titanium surface, the content of titanium and oxygen elements seemed to decrease on the titanium surface, and the hydrophilicity of the titanium surface declined. CONCLUSIONS: LDL can adsorb on titanium surface, which can change the physical and chemical properties of titanium surface to a certain extent. References | Related Articles | Metrics

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Study on cushioning and energy absorption of sports mouthguard BAO Shi-jie, YE Sheng-jia, REN Xiao-wei, LI Yi-han, CHEN Qu-yi, WEI Bin, GONG Yao 2021, 30 (1):  55-60.  doi: 10.19439/j.sjos.2021.01.011 Abstract ( 433 )   PDF (4496KB) ( 247 )   PURPOSE: Using impact test to study cushioning and energy absorption of sports mouthguard of different thickness, material and combination. METHODS: According to the thickness, material and combination, the mouthguards were divided into 7 groups with 6 testing pieces in each group. A pendulum device was used to apply impact energy to the mouthguard and dentition model, and the magnitude of the impact energy was measured by changing the release height of the pendulum. The force sensor and the laser vibrometer were respectively connected to the data acquisition and signal analyzer to obtain the incident speed, rebound speed, maximum collision force, collision start time and collision end time of the hammer head. Collision time, energy absorption and energy absorption ratio of the mouthguard were calculated, which reflected different mouthguard cushioning and energy absorption characteristics. One-way analysis of variance and t test in SPSS 22.0 software package was used to analyze the difference between different groups. RESULTS: No matter what type of mouthguard was worn by the dentition model, the impact force was significantly reduced than without mouthguards. At the same height, there was significant difference between the average maximum collision force and the average collision time among soft mouthguards with thicknesses of 2, 3, 4, and 5 mm(P<0.05); among which the average maximum collision force of the 5 mm was the smallest and the average collision time was the shortest. There was no significant difference in the average energy absorption and the average energy absorption ratio among these 4 groups. There was significant difference in the average maximum collision force, average collision time, average energy absorption and average energy absorption ratio between the two groups of mouthguards with the same thickness of splints and different materials(P<0.05). Among them, the average maximum impact force of the 4 mm soft mouthguard was smaller and the average collision time was longer. CONCLUSIONS: Wearing sports mouthguard can reduce the risk of tooth fracture during collision. Soft mouthguard has the best cushioning performance and it is positively related to thickness. Locally strengthening hard materials can enhance energy absorption and provide better protection. References | Related Articles | Metrics

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Preliminary clinical study on the effect of metformin on prognosis of patients with oral squamous cell carcinoma after surgical treatment HUANG Dan-ni, CHEN Wen-xin, XIONG Hao-feng, HU Xin, MAO Ting, SU Tong 2021, 30 (1):  61-65.  doi: 10.19439/j.sjos.2021.01.012 Abstract ( 887 )   PDF (3482KB) ( 195 )   PURPOSE: To investigate the effect of metformin on the prognosis of patients with oral squamous cell carcinoma after surgical treatment. METHODS: Three hundred and forty-six patients with oral squamous cell carcinoma after operation in Xiangya Hospital of Central South University from October 2015 to October 2016 were selected and divided into experimental group and control group. In the experimental group, 71 patients with oral squamous cell carcinoma received metformin after surgery. The control group included 275 patients without metformin after surgery of oral squamous cell carcinoma. The clinical follow-up results of patients in the two groups were compared. SPSS 21.0 software package was used to analyze the data. RESULTS: Compared with the control group, the recurrent rate of the experimental group was lower. The difference was more significant in male patients, patients with primary tongue tumor, patients with highly differentiated squamous cell carcinoma, patients with cervical lymph node metastasis, and patients with a history of chewing areca nut (P<0.05). CONCLUSIONS: Metformin can decrease postoperative recurrent rate and metastatic rate of oral squamous cell carcinoma after surgery. References | Related Articles | Metrics

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Evaluation of caries prevention effect of multi-dimensional oral cleaning intervention model for regional preschool children CHEN Qi-wen, YUAN Shuang, SHI Le 2021, 30 (1):  66-70.  doi: 10.19439/j.sjos.2021.01.013 Abstract ( 226 )   PDF (3627KB) ( 222 )   PURPOSE: Caries prevention for preschool children (aged 3-6 years) was always the focus of oral public health work for children. The purpose of this study was to explore the caries prevention effect of multi-dimensional oral cleaning intervention model for regional preschool children in shanghai. METHODS: Twelve kindergartens were randomly selected and divided into control group and experimental group（each group with 300 children aged 3-4 years old） in October 2016. Children in the control group received routine oral health education, while children in the experimental group adopted multi-dimensional oral cleaning intervention model. After 2 years of follow-up, oral cleaning behavior and caries status of children were analyzed with SPSS 22.0 software package. RESULTS: The experimental group was significantly higher than the control group in brushing frequency, brushing time, correct brushing method, fluoride toothpaste and floss using (P<0.01), and caries rate and dmft index of the experimental group were significantly lower than the control group(P<0.01). CONCLUSIONS: For caries prevention in preschool children, multi-dimensional oral cleaning intervention mode plays a positive and effective role in changing children's and parents' oral health knowledge, trust and practice. It also guides and monitors parents to conduct effective oral cleaning behavior in preschool children and reduce the risk of caries. References | Related Articles | Metrics

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Factors associated with psychological distress after surgery and quality of life before and after radiotherapy in 216 patients with oral squamous cell carcinoma WANG Shu-bin, QIN Shuai-hua, YI Ya-qun, LI Xin-ming 2021, 30 (1):  71-76.  doi: 10.19439/j.sjos.2021.01.014 Abstract ( 651 )   PDF (4913KB) ( 184 )   PURPOSE: To investigate the degree of psychological distress of patients with oral squamous cell carcinoma after operation and its influencing factors, and the impact of radiotherapy on their quality of life. METHODS: Univariate analysis and regression analysis were used to evaluate the relationship between psychological distress and socio-economic and therapeutic factors. The quality of life of the subjects before and after radiotherapy was evaluated by paired t-test using the Chinese version of European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30/ Head and Neck 35. SPSS 22.0 software package was used to deal with the data. RESULTS: Age, AJCC stage and median incision of lower lip were the main factors affecting psychological distress. In addition, there were significant differences in scores of most functional areas and specific items before and after radiotherapy. CONCLUSIONS: Clinicians should select individualized treatment programs and procedures for patients of different ages and stages, and screen high-risk groups for psychological distress and provide additional psychological and social support. In addition, radiotherapy can improve or aggravate some special symptoms of patients. Clinicians should take targeted preventive measures. References | Related Articles | Metrics

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Effect of conservative treatment on jaw symmetry of children with unilateral condylar fracture YAO Zhi-tao, AN Wei, MAIMAITITUXUN·Tuerdi 2021, 30 (1):  77-80.  doi: 10.19439/j.sjos.2021.01.015 Abstract ( 238 )   PDF (3316KB) ( 161 )   PURPOSE: To investigate the effect of conservative treatment of unilateral condylar fractures on jaw symmetry in children. METHODS: Twenty-four children with unilateral condylar fractures were divided into control group and experimental group according to the treatment methods, with 12 cases in each group. The control group received surgery, and the experimental group received conservative treatment with intermaxillary traction combined with occlusal pads. The treatment effects of the two groups were compared, and the imaging improvement, three-dimensional structure of the jaw, mandibular motor and occlusal relationship, and facial nerve injury were compared after treatment. SPSS 17.0 software package was used for statistical analysis. RESULTS: There was no significant difference in the total effective rate, total effective rate of imaging, disturbance of occlusal relationship, and incidence of facial nerve injury between the two groups (P>0.05). The transverse diameter of the condyles was significantly longer in the experimental group than in the control group, and the width of the condyles and bony condylar deflection in the experimental group were significantly smaller than those in the control group (P<0.05). The degree of mouth opening after treatment in both groups was increased, which was more remarkably in the experimental group after treatment than in the control group (P<0.05). CONCLUSIONS: Children with unilateral condylar fractures can obtain similar treatment effects with surgical treatment with conservative treatment. After treatment, the children's mandibular motor function and jaw symmetry are well restored. References | Related Articles | Metrics

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Study on the changes of soft and hard tissue before and after early treatment of ClassⅡskeletal malocclusion with Twin-block appliance NIU Shu-qiang, HOU Feng-chun, ZHANG Qian-qian, ZANG Yan-jun 2021, 30 (1):  81-84.  doi: 10.19439/j.sjos.2021.01.016 Abstract ( 528 )   PDF (2958KB) ( 259 )   PURPOSE: To investigate the effect of early correction with Twin-block appliance on soft and hard tissues of patients with Class Ⅱ skeletal malocclusion. METHODS: Sixty patients with Angle Class Ⅱ skeletal malocclusion were prospectively selected. The patients were divided into 2 groups, 30 cases in each group, by random number table method. Patients in the experimental group were treated with a Twin-block appliance combined with straight wire appliance, while patients in the control group were treated with a straight wire appliance. The soft and hard tissue indexes(SNA, SNB, ANB, U1-NA angle, U1-NA distance, L1-NB distance, L1-NB angle, U1-L1) before, and 12 months after treatment were measured. Soft tissue measurement indicators included UL-U1, LL-L1, over jet, overbite, E-upper-lip from the upper lip to the E-line, and the lower lip to the E-line, changes in the vertical distance (E-lower-lip), the dip angle of the sulcus, and the thickness of the soft tissue. SPSS 25.0 software package was used for statistical analysis of the data. RESULTS: U1-NA, U1-NA, L1-NB, L1-NB, overjet, overbite, E-upper-lip, and E-lower-lip were significantly less than the control group at 12 months and 36 months after treatment in the experimental group(P<0.05). U1-L1, nasolabial angle, sulcus angle, and soft tissue thickness of the experimental group were significantly greater than those of the control group(P<0.05). CONCLUSIONS: Twin-block appliance combined with straight wire appliance can significantly improve the relationship between the jaw and the soft and hard tissues of patients with Class Ⅱ skeletal malocclusion, and the long-term effect is good. References | Related Articles | Metrics

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Effects of different orthodontic treatments on sputum chemokines CX3CL1, RANKL/OPG levels in patients with malocclusion LIN Jia-xu, ZHANG RU-hong, ZHANG Jian-na, WU Xiao-ping 2021, 30 (1):  85-88.  doi: 10.19439/j.sjos.2021.01.017 Abstract ( 234 )   PDF (2951KB) ( 175 )   PURPOSE: To investigate the effects of different orthodontic treatments on gingival crevicular fluid chemokine CX3CL1, nuclear factor κB receptor activating factor ligand/osteoprotegerin(RANKL/OPG) levels in patients with malocclusion. METHODS: Ninety-six patients with malocclusion who were scheduled to undergo orthodontic treatment were randomly divided into four groups. All patients were treated with square wire appliance, and 0, 50, 150, 250 g of far-distal orthodontic force were given respectively. The levels of CX3CL1 and RANKL/OPG in gingival crevicular fluid were detected in four groups after 1, 2, 3, and 4 weeks of treatment. SPSS 25.0 software package was used for statistical analysis of the date. RESULTS: The levels of CX3CL1, RANKL and RANKL/OPG in the gingival crevicular fluid of the four groups were continuously increased after treatment for 1-3 weeks, and decreased after 4 weeks of treatment (P<0.05). The OPG in the gingival crevicular fluid was at a low level after 1-3 weeks of treatment. There was an increase after 4 weeks of treatment (P<0.05). The levels of CX3CL1, RANKL, OPG and RANKL/OPG in gingival crevicular fluid increased gradually in group A, B, C and D (P<0.05), and the differences between the groups were statistically significant (P<0.05).CONCLUSIONS: The levels of CX3CL1 and RANKL/OPG in gingival crevicular fluid are closely related to orthodontic force and treatment time, and can be used as an index to evaluate orthodontic treatment of alveolar bone remodeling. References | Related Articles | Metrics

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Therapeutic effect of Actovegin on acute oral mucositis caused by radiotherapy DONG Zhen-yao, YANG Shi-rong, YAO Yi-zhang 2021, 30 (1):  89-92.  doi: 10.19439/j.sjos.2021.01.018 Abstract ( 315 )   PDF (2998KB) ( 171 )   PURPOSE: To explore the clinical effect of Actovegin in the treatment of acute oral mucositis in patients with radiotherapy. METHODS: One hundred and thirteen patients with acute oral mucositis caused by radiotherapy for nasopharyngeal carcinoma admitted to the Department of Oncology, the Fifth People's Hospital of Qinghai Province from July 2015 to September 2017 were randomly divided into the experimental group (57 cases) and control group (56 cases). Patients in the experimental group were treated with Aiweizhi, while patients in the control group were treated with new rehabilitation. The changes of VAS score, oral mucositis grade, serum CRP, IL-6, TGF-β1 and TNF-α were compared between the 2 groups. The data were analyzed with SPSS 16.0 software package. RESULTS: Before treatment, there was no significant difference in VAS score between the 2 groups (P>0.05). After 1 week and 2 weeks of treatment, the VAS scores of the two groups were significantly lower than those before treatment (P<0.05). The VAS score of the experimental group was significantly lower than that of the control group (P<0.05). After 2 weeks of treatment, oral mucositis grade of the experimental group was significantly lower than that of the control group (P<0.05). There was no significant difference in serum CRP, IL-6, TGF-β1, and TNF-α level between the 2 groups before treatment (P>0.05). After 2 weeks of treatment, the level of serum CRP, IL-6, TGF-β1, and TNF-α in both groups was significantly lower than that before treatment (P<0.05). The serum level of CRP, IL-6, TGF-β1 and TNF-α in the experimental group was significantly lower than that in the control group (P<0.05). CONCLUSIONS: Actovegin has a clear clinical effect on acute oral mucositis in patients with radiotherapy, which can significantly alleviate the pain of patients and reduce the level of serum inflammatory factors. References | Related Articles | Metrics

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Clinical application of vascularized free fibular bone flap for repairing segmental mandibular defects in 40 cases WU Yuan, GAO Peng, LI Hai-tao 2021, 30 (1):  93-96.  doi: 10.19439/j.sjos.2021.01.019 Abstract ( 179 )   PDF (3016KB) ( 151 )   PURPOSE: To investigate the effect of vascularized free fibular flap in repairing segmental mandibular defects. METHODS: Eighty patients with segmental mandibular defects treated in our hospital from June 2015 to May 2018 were enrolled. Both groups of patients were operated by the same group of medical staff with more than 5 years of clinical experience. Patients were divided into 2 groups using a random number table method, 40 in each group. Patients in the control group underwent non-vascularized iliac bone graft while patients in the experimental, group underwent vascularized free fibular bone flap repair. The graft survival, pain, quality of life, negative emotions and complications were compared between the two groups using SPSS 22.0 software package. RESULTS: There was no significant difference in the scores of the proximal gingival papilla, distal gingival papilla, labial margin and labial margin (P>0.05). The gingival texture, color score and total score of the root surface of the experimental group were significantly higher than the control group (P<0.05). The scores of VAS, anxiety and depression in both groups were significantly decreased after operation, but the decrease in the experimental group was greater(P<0.05). Physical function, psychological and social function, life quality of the two groups were significantly increased, but the increase of the experimental group was greater (P<0.05).Three cases (7.5%) developed complications in the control group, including 1 case of pneumonia, 1 case of infection and 1 case of wound recurrence. Two cases(5%) in the experimental group developed of complications, including 1 case of wound recurrence and 1 case of pneumonia, the difference was not statistically significant (P>0.05). CONCLUSIONS: Repair of mandibular segmental defect with vascularized free fibular bone flap can significantly improve the overall effect, relieve pain and negative emotion, improve quality of life of patients and decrease incidence of complications. References | Related Articles | Metrics

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Clinical effect of subgingival sandblasting with glycine powder on prevention of peri-implantitis WU Zhen, ZHU Cao-yun, XIA Ye 2021, 30 (1):  97-99.  doi: 10.19439/j.sjos.2021.01.020 Abstract ( 312 )   PDF (2589KB) ( 194 )   PURPOSE: To evaluate the clinical effect of subgingival sandblasting with glycine powder on prevention of peri-implantitis. METHODS: One hundred and eight patients underwent dental implantation at First Outpatient Department from January 2017 to January 2018 were divided into 3 groups, i.e., subgingival sandblasting group(group A,n=60), subgingival ultrasound group (group B, n=60) and control group (group C, n=60). The occurrence of peri-implantitis among 3 groups was compared. Statistical analysis was conducted with SPSS 17.0 software package. RESULTS: Eighteen months after dental implantation, the rate of peri-implantitis in subgingival sandblasting group was significantly lower than that of subgingival ultrasound group and control group (P=0.04). There was significant difference in probe depth, bleeding index and plaque index among the three groups(P<0.05). CONCLUSIONS: Subgingival sandblasting with glycine powder can significantly reduce the occurrence of peri-implantitis, and can be an effective maintenance method for implant denture. References | Related Articles | Metrics

Clinical Reports

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Short-term prognosis of laterally luxated primary teeth left without treatment: a retrospective study of 45 consecutive cases SHENG Kai, LAI Guang-yun, ZHAO Shi-min 2021, 30 (1):  100-103.  doi: 10.19439/j.sjos.2021.01.021 Abstract ( 335 )   PDF (3210KB) ( 197 )   PURPOSE: To study the clinical prognosis of laterally luxated primary teeth after 6-month follow-up without treatment. METHODS: Patients with laterally luxated primary teeth, visiting Department of Pediatric Dentistry, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from March 2018 to March 2019, were selected for the study. Based on the inclusion and exclusion criteria, totally 45 patients with 57 primary teeth were included. The reposition outcomes and pulp prognosis were reviewed at the end of follow-up. The data were analyzed using SPSS 23.0 software package. RESULTS: During a 6-month follow-up, 92.98% of the luxated teeth showed spontaneous reposition while only 31.58% of the traumatic teeth were back to the original position. Regarding the pulp healing complications, 54.39% of the luxated teeth exhibited no clinical symptoms, and 14.04% of the evaluated teeth displayed pulp canal obliteration, and pulp necrosis happened in 31.58% of the injured teeth. There was significant difference in the reposition outcome between labial-palatal luxation and mesial-distal luxation(P<0.05), but no significant difference was found in pulp prognosis between the two luxation types(P>0.05). Spontaneous reposition and crown discoloration observed in most of the evaluated cases, were the earliest signs after one-month follow-up. Periapical translucent image and root resorption due to periapical inflammation showed within the first three months after injury, pulp canal obliteration appeared after 6 months. CONCLUSIONS: In general, most of the laterally luxated teeth left without treatment can reposition spontaneously and show lower incidence of pulp necrosis compared with mature permanent teeth in half a year after injury. The direction of luxation does not affect pulp prognosis but has an influence on teeth reposition procedure. References | Related Articles | Metrics

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Clinical analysis and countermeasures of 739 cases treated in the emergency department of stomatology in general hospital during COVID-19 epidemic LYU Chun-hua, ZHANG Guo-qin, GAO Zhen-ran, SHENG Lei, MA Song-bo, LIU Jian 2021, 30 (1):  104-108.  doi: 10.19439/j.sjos.2021.01.022 Abstract ( 369 )   PDF (3825KB) ( 238 )   PURPOSE: In this paper, based on the age, sex, disease type, and consultation time of dental emergency during COVID-19 epidemic, a comprehensive analysis of dental emergency management and prevention and control of COVID-19 was conducted. METHODS: A total of 739 emergency dental cases were collected from January 29 2020 to February 28 2020. They were divided into 3 groups,including adolescents (≤18 years), young adults (18 ~ 60 years), and elderly ( ≥60 years old). The data was analyzed using SPSS 21.0 software package. RESULTS: The ratio of male to female was 1.24∶1. There were 655 emergency cases during the day and 84 cases during the night. The types of diseases included pericoronitis (15.83%), apical periodontitis (14.21%), pulpitis (13.40%), periodontitis (12.31%), oral mucosal disease (12.18%), Oral and maxillofacial trauma (10.55%), oral and maxillofacial space infection (8.39%), dental disease in children (5.41%), oral and maxillofacial tumors (2.84%), temporomandibular joint dislocations and disorders (1.76%), and others (3.11%). CONCLUSIONS: Under the epidemic situation of the new coronavirus, as one of the high-risk departments, it is of great significance to enhance the clinical emergency skills and ability of emergency treatment, improve patients' oral health awareness, address the diagnosis and treatment of essential diseases, for the improvement the quality of dental medical care and the prevention and control of COVID-19 epidemic. References | Related Articles | Metrics

Dental Education

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Application of Vectra® 3D facial imaging technology in orthodontic teaching program LIU Qian, YAO Ying, BI Hui-xian, JIN Zuo-lin, YANG Hong-xu, GUO Tao 2021, 30 (1):  109-112.  doi: 10.19439/j.sjos.2021.01.023 Abstract ( 241 )   PDF (3228KB) ( 231 )   PURPOSE: To evaluate the effectiveness of Vectra® 3D facial imaging technology in enhancing orthodontic teaching and training efficiency. METHODS: Thirty-two dental students, enrolled in 2014 as five-year and eight-year curriculum in School of Somatology, Air Force Military Medical University were selected as the subjects of this research. As an important teaching facility for training the students to practice orthodontic clinical examinations, 2D and 3D facial imaging systems were selected in this study for the students to collect and analyze the data relating to the facial complexion and appearance. The students were at first instructed to use the traditional 2D facial imaging system for 20 minutes, and then Vectra® 3D facial imaging system for another 20 minutes. The students were required to deliberate on the specifically designed questionnaires to input their own assessment on these two modalities. The outcomes were quantitatively analyzed using SPSS 24.0 software package. RESULTS: As to the items 2, 5, 6 and 7 in the questionnaire, which indicated the following queries respectively: whether the use of imaging systems could inspire students’ learning interest, whether the results drawn from these two imaging facial systems were accurate and reliable, whether the subjective bias were trivial , and whether these two imaging systems were feasible for orthodontic treatment appraisals. The results showed that there were significant differences in these four items between the two groups（P<0.05). As to the Items 1, 3 and 4 , namely, whether the acquisition of the teaching materials was an easy access, whether these two facial analytical regimes were beneficial for the students to obtain the new knowledge, and whether this specific teaching facility was easy for the students to manage, there was no significant difference between the two groups (P>0.05). CONCLUSIONS: Served as a new teaching syllabus facilitation, Vectra® three-dimensional facial imaging system demonstrates a more satisfactory impetus for the students to learn than the traditional two-dimensional imaging system. Pragmatically, the analytical data resulted from the former remains more accountable than that of the latter. References | Related Articles | Metrics