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25 June 2022, Volume 31 Issue 3 Previous Issue    Next Issue

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CONTENTS 2022, 31 (3):  224-224.  Abstract ( 72 )   PDF (735KB) ( 63 )   Related Articles | Metrics

Original Articles

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Effect of low magnitude tension on the inflammatory response of periodontal ligament cells induced by isoproterenol WANG Xue-chun, WU Yan-qi, MEI Peng, ZHANG Bo-jun, ZHU Min 2022, 31 (3):  225-231.  doi: 10.19439/j.sjos.2022.03.001 Abstract ( 284 )   PDF (1258KB) ( 210 )   PURPOSE: To investigate the effect of tension on the inflammatory response of human periodontal ligament cells (PDLCs) induced by isoproterenol (ISO) and its molecular mechanism. METHODS: Human PDLCs were cultured in vitro and stimulated with a certain concentration of ISO(0.01, 0.1, 1 μmol/L) for 24 h. Cyclic tensile strain with different degrees of elongation (5%, 10% and 15%) were applied. The expression of IL-1β and IL-6 mRNA in PDLCs was detected by real-time quantitative PCR(RT-qPCR). The protein expression of p-PERK, PERK, p-eIF2α, eIF2α and ATF4 related to ER stress was detected by Western blot. The expression of PERK gene in PDLCs was knocked down by cell transfection technique, and the expression of IL-1β and IL-6 mRNA in PDLCs with low expression of PERK was detected by RT-qPCR under the stimulation of ISO and low magnitude tension. Statistical analysis was conducted with SPSS 22.0 software package. RESULTS: ISO induction could significantly up-regulate the IL-1β and IL-6 mRNA expression in PDLCs(P<0.05). Compared with the control group, the expression of IL-1β and IL-6 mRNA in PDLCs induced by ISO was inhibited by low magnitude tension, and the difference was statistically significant(P<0.05). Western blot results showed that low magnitude tension could inhibit the ISO-stimulated phosphorylation of PERK and eIF2α and the expression of ATF4（P<0.05）. Compared with the negative control group, IL-1β and IL-6 mRNA expression was decreased in the ISO-stimulated PDLCs silenced by PERK gene. CONCLUSIONS: Tension with 5% degrees of elongation may inhibit ISO-stimulated periodontal inflammatory response through endoplasmic reticulum stress pathway. References | Related Articles | Metrics

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Effects of human periodontal ligament fibroblast-derived exosomes on reducing rat root resorption after delayed tooth replantation YIN Yue, TAO Shuo, ZHANG Qi 2022, 31 (3):  232-236.  doi: 10.19439/j.sjos.2022.03.002 Abstract ( 244 )   PDF (2126KB) ( 211 )   PURPOSE: To explore the effect of healthy human periodontal ligament fibroblasts (hPDLFs) -derived exosomes on tooth resorption after delayed tooth replantation in rats and its possible mechanism. METHODS: The exosomes derived from hPDLFs were isolated and identified in thirty six-week-old SD rats and randomly divided into control group and exosome group. The right maxillary first molar was extracted to establish a delayed tooth replantation model. The dislocated teeth were implanted back into the alveolar fossa after 30 minutes. 40 μL Hanks' balanced salt solution (HBSS) were injected into the periodontal tissue, and the experimental group was injected with 40 μL HBSS containing exosomes. The rats were sacrificed at 1, 2, and 4 weeks. Hematoxylin-eosin (H-E) staining was used to observe tooth resorption. Tartrate-resistant acid phosphatase(TRAP) staining was used to observe the number of osteoclasts. The expression of osteoprotegerin(OPG) in periodontal ligament was detected by immunohistochemical staining. The differences in distribution of each genotype were analyzed with SPSS 17.0 software package. RESULTS: The identification experiment showed that extracellular vesicles were exosomes. hPDLFs-derived exosomes inhibited root resorption after delayed tooth replantation, reduced the expression of TRAP-positive osteoclasts (P<0.05), and promoted expression of OPG in periodontal ligament (P<0.05). CONCLUSIONS: After delayed tooth replantation, PDLFs-derived exosomes reduce the number of osteoclasts, promote OPG expression in the periodontal ligament, and reduce tooth root resorption after replantation. References | Related Articles | Metrics

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Effects of miR-31-5p on HIF-1α/BNIP3 signaling pathway and the expression of osteoblast-related factors of dental pulp stem cells FU Hong-hai, SUN Le-gang, DING Chang-cheng, MA Xiang-rui, HUANG Yu-mei 2022, 31 (3):  237-242.  doi: 10.19439/j.sjos.2022.03.003 Abstract ( 250 )   PDF (865KB) ( 170 )   PURPOSE: To investigate the effects of microRNA-31-5p (miR-31-5p) on the signal pathway of hypoxia inducible factor-1α (HIF-1α)/Bcl-2/adenovirus E1B 19-kDa-interacting protein 3(BNIP3) and the expression of osteoblast-related factors of dental pulp stem cells(DPSCs). METHODS: Human dental pulp stem cells (DPSCs) were cultured in vitro and divided into the control group (no transfection), mimic NC group (transfected with negative control-miR-31-5p), miR-31-5p mimic group (transfected with hsa-miR-31-5p mimic), siRNA NC group (transfected with nonsense siRNA) and miR-31-5p siRNA group (transfected with miR-31-5p siRNA).The expressions of miR-31-5p, HIF-1α, BNIP3, alkaline phosphatase(ALP) and Runt-related transcription factor-2(Runx2) mRNA in DPSCs were detected by real-time fluorescence quantitative PCR; the proliferation of DPSCs was detected by MTT; ALP activity of DPSCs was detected by ALP activity test kit; and the protein expressions of HIF-1α, BNIP3 and Runx2 in DPSCs were detected by Western blot. Statistical analysis was carried out with SPSS 24.0 software package. RESULTS: Compared with the control group and mimic NC group, the A value, ALP mRNA expression level and activity, Runx2 mRNA and protein expression levels of DPSCs in miR-31-5p mimic group were significantly lower (P<0.05), ALP staining decreased significantly, and the expression levels of miR-31-5p mRNA, HIF-1α, BNIP3 mRNA and HIF-1α, BNIP3, Beclin1 protein were significantly higher (P<0.05). Compared with the control group and siRNA NC group, the A value, ALP mRNA expression level and activity, Runx2 mRNA and protein expression levels of DPSCs in miR-31-5p siRNA group were significantly higher (P<0.05), ALP staining enhanced significantly, and the expression levels of miR-31-5p mRNA, HIF-1α, BNIP3 mRNA and HIF-1α, BNIP3, Beclin1 protein were significantly lower(P<0.05). CONCLUSIONS: MiR-31-5p may inhibit the expression of osteoblast-related factors of DPSCs, and activating HIF-1α/BNIP3 signaling pathway. References | Related Articles | Metrics

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The effect of inflammation on proliferation and osteogenic differentiation of periodontal ligament cells DONG Jia-chen, SHU Rong 2022, 31 (3):  243-247.  doi: 10.19439/j.sjos.2022.03.004 Abstract ( 269 )   PDF (916KB) ( 246 )   PURPOSE: To investigate the effects of inflammatory microenvironment on proliferation and osteogenic differentiation of periodontal ligament cells(PDLCs) in vitro. METHODS: Human PDLCs were isolated and characterized. MTT was used to investigate the proliferation rate of PDLCs under different concentration of lipopolysaccharide（LPS）. The PDLCs' osteogenic differentiation was investigated using real-time PCR and Western blot. The date were statistically analyzed with SPSS 13.0 software package. RESULTS: Treatment with 0.1 μg/mL LPS increased proliferation of PDLCs and enhanced the expression of osteogenic gene and protein. The proliferation of PDLCs and expression of alkaline phosphatase(ALP), RUNX2, Collagen-I, BMP2 were significantly decreased by 10 μg/mL LPS. CONCLUSIONS: The inflammatory microenvironment (10 μg/mL LPS) inhibits the proliferation and osteogenic differentiation of human PDLCs. References | Related Articles | Metrics

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Preliminary establishment of an unsupervised quantification model of Ki-67 proliferation index based on local variable threshold method QIN Zhi-ming, JIE Wei-ping, CHI Yan-ting, LI Hong-feng, LI Bin-bin 2022, 31 (3):  248-254.  doi: 10.19439/j.sjos.2022.03.005 Abstract ( 265 )   PDF (2270KB) ( 152 )   PURPOSE: To develop an effective machine learning method for estimation of Ki-67 cell proliferation index. METHODS: Oral squamous cell carcinoma(OSCC) slices were selected for Ki-67 immunohistochemical staining. The digital pathology images were obtained through whole-slide imaging technology. Variable threshold method based on local statistics was applied to preprocess the images, aiming at reducing the noise in the images. Adaptive threshold method was used to remove the irrelevant light-colored background area in the image, retaining the nucleus part. A threshold method in space was applied to differentiate brown from blue content. Finally, the proliferation index was estimated and compared with manual and the color deconvolution method by paired sample t test and spearman correlation coefficients with SPSS 24.0 software package. RESULTS: A new nucleus detection and classification method was established, which can process pathologic images of different sizes, and effectively detect immunohistochemical brown positive cells and blue negative cells. There was no significant difference between this algorithm and manual counting（P>0.05）, but the speed was faster. The calculation efficiency advantage was more obvious when processing a large image, and the detection result of Ki-67 proliferation index was better than the commonly used color deconvolution method（P<0.05）. CONCLUSIONS: The automatic nucleus quantitative analysis method developed in this study can analyze Ki-67 staining of the nucleus in OSCC cells efficiently and calculate the proliferation index, which can be used for auxiliary diagnosis in pathology. References | Related Articles | Metrics

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The effect of osthole on lipopolysaccharide-induced macrophages polarization and inflammatory reaction WANG Fei-fei, RAO Ding-cheng, JIN Si-yu, YANG Pei-ming, ZHOU Yong-mei, WAN Guang-yong 2022, 31 (3):  255-259.  doi: 10.19439/j.sjos.2022.03.006 Abstract ( 230 )   PDF (1224KB) ( 244 )   PURPOSE: To investigate the effect of Osthole (OST) on lipopolysaccharide (LPS)-induced macrophage polarization and inflammatory reaction. METHODS: The effect of different concentrations of OST on proliferative activity of RAW264.7 macrophages was examined by CCK-8 method; the effect of OST at different concentrations (6.25, 12.5 and 25 μmol/L) on macrophage polarization and inflammation was investigated by using intracellular reactive oxygen species (ROS) detection kit (DCFH-DA), immunofluorescence staining, q-PCR and flow cytometry. The effects of OST on macrophage polarization and inflammatory responses were investigated by immunoblotting of proteins. Graphpad prism 8.0 software package was used for statistical analysis of the data. RESULTS: CCK-8 results showed that OST was not significantly cytotoxic to RAW264.7 at less than 25 μmol/L, immunofluorescence and q-PCR results showed that OST at 6.25, 12.5 and 25 μmol/L inhibited the expression of inflammatory factors in M1 macrophages, and iNOS, TNF-α, CCR7 were reduced in a concentration-dependent manner, and effectively upregulated the expression of M2 inflammatory factors IL-10, Arg-1 and CD206. Flow cytometry showed that OST effectively inhibited the expression of LPS-induced M1 marker CD86 in macrophages. CONCLUSIONS: OST can regulate lipopolysaccharide-induced M1 macrophages polarization and reduce inflammatory reaction. References | Related Articles | Metrics

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Evaluation of the effect of digital crown extension guide in aesthetic restoration of anterior teeth WANG Xue-chun, WANG Yong, XU Xiao-bo, HAO Xin-he 2022, 31 (3):  260-264.  doi: 10.19439/j.sjos.2022.03.007 Abstract ( 375 )   PDF (749KB) ( 448 )   PURPOSE: To evaluate the clinical effect of three-dimensional digital smile design (3D-DSD) combined with double positioning crown extension guide in aesthetic restoration of anterior teeth. METHODS: Twenty patients who needed aesthetic crown lengthening and full crown restoration of upper anterior teeth were selected and randomly divided into the experimental group and control group, with 10 cases in each group. The experimental group carried out 3D-DSD, after confirming the plan, 3D printed double positioning crown extension guides were used to guide aesthetic crown lengthening, and full crown was completed 3 months after operation. The control group used traditional aesthetic crown lengthening and full crown restoration. PES/WES evaluation was performed before operation, three months and six months after operation. Visual analogue scales(VAS) were used to evaluate patient satisfaction 6 and 7 months after surgery, and the repeatability evaluation of VAS was conducted. The correlation between PES/WES score and overall satisfaction was analyzed 6 months after operation. SPSS 23.0 software package was used for statistical analysis. RESULTS: The PES/WES scores of the two groups of patients at 3 months and 6 months after operation were higher than those before operation(P<0.05). The two groups showed that the scores of the experimental group were significantly higher than those of the control group for PES 3 months after operation, PES and WES 6 months after operation(P<0.05).Satisfaction survey results showed that the intra-group correlation coefficient of the two VAS results was 0.956(P<0.05),and crown length-to-width ratio, smile curve, personality characteristics, patient participation and overall satisfaction in the experimental group were better than those of the control group(P<0.05).The results of Speraman correlation analysis showed that PES and WES scores at 6 months after operation were positively correlated with overall satisfaction (rs1=0.905, P<0.001; rs2=0.460, P=0.041). CONCLUSIONS: 3D digital smile design combined with double positioning crown extension guide guides the anterior aesthetic crown lengthening and restoration treatment, which can improve the effect of pink and white aesthetics after treatment and patient satisfaction. References | Related Articles | Metrics

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Clinical effects of two different hydroxyapatite bone graft materials during maxillary sinus lifting surgery with bone grafting and simultaneous implantation of implants LIU Fang, LI Zhen, XIE Xiao-fei, LU Xiao-miao, ZHANG Rong-xiu, XU Li, ZHANG Kai 2022, 31 (3):  265-269.  doi: 10.19439/j.sjos.2022.03.008 Abstract ( 290 )   PDF (580KB) ( 181 )   PURPOSE: To compare the clinical effects of two different hydroxyapatite bone graft materials in maxillary sinus lifting surgery with bone grafting and implantation at the same time. METHODS: Seventy-two patients with implantation in the maxillary posterior dental area and insufficient bone mass admitted to the First Affiliated Hospital of Bengbu Medical College were collected from March 2018 to April 2019, and they were divided into experimental group(n=36) and control group(n=36) by random number table. Patients in the control group used hydroxyapatite composite material, while patients in the experimental group used nano-hydroxyapatite composite material. The clinical effects, bone increment and bone density changes of the two groups of implants were compared, and postoperative implant stability and complications of the two groups were compared. Statistical analysis was performed with SPSS 18.0 software package. RESULTS: The survival rate of implants in the experimental group was significantly higher than that in the control group at 24 months (P<0.05). Alveolar bone resorption in the experimental group was significantly lower than the control group 6 months after surgery(P<0.05). The bone mineral density of implants in the experimental group was significantly higher than the control group 6 months and 12 months after operation(P<0.05). The implant stability coefficient value of the experimental group was significantly higher than the control group 12 months after operation(P<0.05). There was no significant difference in the total complication rate between the two groups(P>0.05). CONCLUSIONS: In maxillary sinus lift, the survival rate of nano-hydroxyapatite composite material implanted in the same period is high, which can improve postoperative bone metabolism and increase implant stability with good safety. References | Related Articles | Metrics

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Differences between oral and intestinal microorganisms of 860 children aged 1-6 years in Nanjing city MA Hao-ran, LIU Zi-han 2022, 31 (3):  270-273.  doi: 10.19439/j.sjos.2022.03.009 Abstract ( 306 )   PDF (1253KB) ( 144 )   PURPOSE: To explore the differences between oral and intestinal microorganisms of 860 children aged 1-6 years in Nanjing city. METHODS: Eight hundred and sixty children aged 1-6 years who met the inclusion criteria were enrolled. 860 saliva samples and equivalent stool samples were collected. Microbial DNA was extracted and amplified using PCR. High-throughput sequencing was performed using Miseq sequencer, and bioinformatics analysis was performed to compare the differences of oral and intestinal microflora. SPSS 20.0 software package was used to perform the statistical analysis. RESULTS: At phylum level, Bacteroidetes (39.98%), Proteobacteria (25.32%) and Firmicutes (21.78%) were the most common microbes in oral cavity, while Firmicutes (45.21%) and Bacteroidetes (37.21%) were the most abundant microbes in the gut. At genus level, the top three microbes in the oral cavity included Prevotella(26.11%), Neisseria (12.39%), Porphyromonas(10.13%), while the top three microbes in the gut included Bacteroidetes(20.11%), Prevotella (9.13%), and Faecalibacterium (5.13%). There were significant alpha and beta differences in oral and intestinal microbial diversity. CONCLUSIONS: Bacteroidetes and Proteobacteria are the dominant species in the oral cavity, while Firmicutes and Bacteroidetes are the dominant species in the gut. There are significant differences in species composition and abundance between oral and intestinal microorganisms. References | Related Articles | Metrics

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Relationship between peripheral blood micronutrients and four kinds of oral mucosal diseases in children: clinical analysis of 217 cases ZHOU Yong, ZHOU Zheng-quan, LIU Xue-wei, ZHANG Li-mu, WANG Ye, LIN Xiao-ping 2022, 31 (3):  274-281.  doi: 10.19439/j.sjos.2022.03.010 Abstract ( 242 )   PDF (1074KB) ( 194 )   PURPOSE: To investigate the relationship between peripheral blood micronutrient levels and 4 kinds of oral mucosal diseases (minor recurrent aphthous ulcer, angular cheilitis, cheilitis and geographic tongue) in children aged 0~14 years. METHODS: One hundred and fifty-two children with oral mucosal lesions (COML) and 65 healthy children (health control group, HC) were included. The clinical data of each group were recorded separately to compare whether there existed differences in the levels of serum water-soluble vitamins (vitamins B1, B2, B3, B5, B6, B7, B9, B12, C), serum fat-soluble vitamins [vitamins A, E, K, 25(OH)D2, 25(OH)D3], zinc and serum calcium. Whether peripheral blood micronutrients were risk factors associated with the onset of COML was analyzed through disorder multiclass logistic regression with SPSS 23.0 software package. RESULTS: Peripheral blood micronutrients differed in children with minor recurrent aphthous ulcers, cheilitis, and geographic tongue (P<0.05). Compared with HC group, children in minor recurrent aphthous ulcer group had significantly lower levels of vitamin B1, B6, B7, C, A, and 25(OH)D3 (P<0.05), and relatively higher rates of vitamin B6 (50.00% vs 13.85%), vitamin B7 (36.76% vs 9.23%), 25(OH)D3 (64.71% vs 36.92%) deficiency and vitamin K excess (8.82% vs 0.00%)(P<0.005). Multiclass logistic regression analysis showed that vitamin B1, vitamin C, vitamin A deficiency, vitamin B5, and vitamin K excess were risk factors for incidence in children with minor recurrent aphthous ulcer, and each element was independent for each other. Compared with HC group, the levels of vitamin B7 and 25(OH)D3 in children with cheilitis were significantly lower(P<0.05), and the rate of vitamin B7 deficiency was significantly higher (P<0.005). Multiclass logistic regression analysis showed that vitamin B7 and vitamin A deficiency were risk factors for cheilitis in children, and the two were independent for each other. Compared with the HC group, vitamin K excess rate was significantly higher in children with geographic tongue (7.14% vs 0.00%) (P<0.005). Multiclass logistic regression analysis showed that vitamin C deficiency and vitamin K excess were risk factors for the incidence of geographic tongue, and the two were independent for each other. Compared with other groups, peripheral blood micronutrients had no correlation with the pathogenesis of angular cheilitis (P>0.05). CONCLUSIONS: The occurrence of COML is closely related to peripheral blood micronutrient levels, which suggests that children with COML need to monitor vitamin and mineral levels and supplement treatment when necessary. References | Related Articles | Metrics

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Research on the pathogeny of black tooth stain and association between black tooth stain and primary dentition caries in children MIAO Fen, MA Hao-ran, LIU Zi-han 2022, 31 (3):  282-285.  doi: 10.19439/j.sjos.2022.03.011 Abstract ( 375 )   PDF (544KB) ( 224 )   PURPOSE: To investigate the related factors of black tooth stain in primary teeth of 3~5 years old children and caries status of primary dentition in these children. METHODS: From December 2019 to August 2020, 182 3~5 years old children with black tooth stain and 200 children without pigmentation were investigated by oral examination and questionnaire survey to their guardians, while caries status , distribution range of the pigment, factors associated with black tooth stain were evaluated. SPSS 20.0 software package was used for data analysis. RESULTS: Children with black tooth stain had fewer dental caries. The lingual surfaces of the mandibular anterior teeth were the most affected sites. Factors associated with black tooth stain were foods with soy sauce and brushing teeth with parents' help. CONCLUSIONS: There is a negative correlation between the occurrence of primary dentition caries and blacktooth stain, but there is no significant correlation between formation of black tooth stain and most environmental factors. References | Related Articles | Metrics

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Relationship between CYP2A6 gene polymorphism and periodontitis, expression of inflammatory cytokines in 123 Han smokers with periodontitis XIANG Ying-hui, WANG Zhan-gang, LI Li-juan, WANG Li-juan, TANG Chen 2022, 31 (3):  286-289.  doi: 10.19439/j.sjos.2022.03.012 Abstract ( 218 )   PDF (512KB) ( 149 )   PURPOSE: To investigate the relationship between polymorphism of cytochrome P450, family 2, subfamily A, polypeptide 6(CYP2A6) and periodontitis, the expression of inflammatory cytokines in 123 Han smokers. METHODS: From October 2018 to October 2019, a total of 123 smokers with periodontitis were selected as the experimental group, and 125 non-smokers as the control group. The general data of the patients were collected, including age, gender, body mass index (BMI), chewing and brushing habits, as well as molar condition; plaque index (PLI), gingival bleeding index (BI), periodontal probing depth (PD) and attachment loss (AL) were detected. CYP2A6 was amplified by PCR. The level of interleukin (IL)-17, IL-1, IL-6, IL-23 and tumor necrosis factor-α (TNF-α) in GCF was detected by enzyme-linked immunosorbent assay(ELISA). SPSS 25.0 software package was used for statistical analysis of the data. RESULTS: There was significant difference in gender, PLI, IL-17, IL-1, IL-6, IL-23, TNF-α level in GCF between the two groups(P<0.05). All samples were amplified by PCR. Among them, 23 were not amplified, which were identified as CYP2A6 deletion type (CYP2A6del), including 5 in the experimental group and 18 in the control group; 225 were amplified and identified as CYP2A6 wild type(CYP2A6wt), including 118 in the experimental group and 107 in the control group. There was significant difference in CYP2A6 genotype between the two groups(P<0.05). In the experimental group, the level of IL-1 and PLI of different CYP2A6 genotypes was significantly different(P<0.05); and in the control group, the level of IL-17 and PLI of different CYP2A6 genotypes was also significantly different(P<0.05). CONCLUSIONS: There are differences in CYP2A6 genotype between smokers and non-smokers in Han population with periodontitis, but the relationship between CYP2A6 genotype and inflammatory cytokines is not clear. References | Related Articles | Metrics

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Effect of different adduction methods of maxillary incisor in adolescents on the shape of alveolar bone XIE Qin, LIN Shan, LIN Li, LI Duo 2022, 31 (3):  290-294.  doi: 10.19439/j.sjos.2022.03.013 Abstract ( 448 )   PDF (595KB) ( 167 )   PURPOSE: To explore the influence of different adduction methods of maxillary incisor in adolescents on the shape of alveolar bone. METHODS: Three hundred and twenty-eight maxillary incisors were collected from 82 patients with jaw protrusion deformity treated in Union Hospital of Fujian Medical University from June 2018 to June 2019. 135 incisors were included in the oblique adduction group, and 193 incisors were included in the root control adduction group. All patients took cone-beam CT(CBCT) to measure the adduction of the maxillary incisor and the changes in alveolar bone height, thickness, and bone density. Statistical analysis was performed with SPSS 18.0 software package. RESULTS: The length of the maxillary incisor to the mid-palatine vertical surface(IE-MP), the long axis of the maxillary incisor and the posterior inferior angle of the palatal plane (LAI-PP) in oblique adduction group were significantly greater than root control adduction group(P<0.05). The length of the maxillary incisor from the apex of the maxillary incisor to the mid-palatine vertical surface(RA-MP) in the oblique adduction group was significantly smaller than the root control adduction group (P<0.05). Postoperative L1, L2, L3, P1, T1 of the oblique adduction group were significantly lower than preoperative values(P<0.05), and postoperative P2, P3, T2, and T3 were significantly higher than preoperative value(P<0.05). Postoperative L1, L2, and L3 of the root control adduction group were significantly higher than those before operation (P<0.05), and postoperative P1, P2, P3, T1, T2, and T3 were significantly lower than those before operation(P<0.05). The changes of L2, L3, P3, T3 of the oblique adduction group were significantly higher than the control root adduction group(P<0.05), and the changes of L1, P1, P2, T1, T2 of the oblique adduction group were all significantly lower than the control root adduction group(P<0.05). There was no significant difference in bone mineral density of the upper and lower jaws between the two groups before and 6 months after operation(P>0.05). CONCLUSIONS: When adolescents' maxillary incisors are retracted in a wide range, the labial apical area, the palatal alveolar ridge area of the oblique adduction group, and the palatal root neck of the root control adduction group are all high-risk areas for alveolar bone resorption. References | Related Articles | Metrics

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Comparison of the effects of removable dentures made by 3D printing and traditional casting methods on patients' subjective feelings YE Rong-rong, ZHONG Qun, WANG Jue, BAO Xiang-jun, GONG Zhi-cheng, JIA Shuang 2022, 31 (3):  295-299.  doi: 10.19439/j.sjos.2022.03.014 Abstract ( 298 )   PDF (2429KB) ( 229 )   PURPOSE: To compare the different effects of removable dentures made by 3D printing and traditional casting methods on patients' subjective feelings. METHODS: A total of 80 patients with dentition defects of Ken’s Class Ⅰ and Subclass Ⅱ were selected from the Department of Prosthodontics. The patients were randomly divided into 2 groups, with removable dentures made by using 3D printing and plaster casting method, respectively. The patients were asked to re-visit 1 week after wearing the dentures to observe and record intraoral mucosal tenderness points. At the same time, mastication efficiency was measured by absorbance method. The patients were followed up for 2 months after wearing dentures, and questionnaires were issued to them to investigate subjective feelings and satisfaction. The subjective feelings of patients included masticatory ability, retention effect, convenience, comfort, speech function and facial appearance. Satisfaction evaluation included three aspects: treatment duration, cost and final outcome. Each aspect of evaluation used a 5-point system, with a minimum score of 1 and a maximum score of 5. The higher the score, the better the patient's subjective feelings or the higher the satisfaction. The data were statistically analyzed with SPSS 17.0 software package. RESULTS: The tender points in 3D printing group was less than the plaster casting group, while the chewing efficiency of 3D printing group was higher than the plaster casting group, the difference was statistically significant (P<0.05). The difference of subjective feeling and satisfaction was also significant between the two groups(P<0.05). CONCLUSIONS: 3D printing to make removable denture has certain advantages in improving the accuracy of removable denture and the comfort of patients. References | Related Articles | Metrics

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Short-term and long-term effects of all-ceramic onlay on restoration of premolars and its influence on dental function XIAO Sha, GAO Cheng-zhi, ZHOU Dong-ping 2022, 31 (3):  300-304.  doi: 10.19439/j.sjos.2022.03.015 Abstract ( 363 )   PDF (597KB) ( 216 )   PURPOSE: To investigate the short-term and long-term effects of all-ceramic onlay on restoration of premolars and its influence on dental function. METHODS: Ninety-five premolars receiving root canal treatment in People's Hospital of Peking University from January 2017 to January 2018 were enrolled, and randomly divided into two groups based on different repairing methods. Patients in the control group (n=47) received full crown restoration, while patients in the experimental group(n=48) received all-ceramic onlay restoration. The success, survival and failure rates of the teeth were compared. The United States Public Health Service(USPHS) and occlusal function of the prosthesis were compared 6, 12 and 36 months after treatment. The data were processed using SPSS 19.0 software package. RESULTS: The success and survival rate of the experimental group were higher than those of the control group, but without significant difference (P>0.05). The morphology, marginal integrity, marginal coloration, surface texture, secondary caries, gingival health and proximal contacts showed no significant difference between the two groups 12 months after treatment(P>0.05). Thirty-six months after treatment, the marginal integrity, marginal coloration and surface texture showed no significant difference between the two groups (P>0.05), while the morphology, secondary caries, gingival health and proximal contacts were significantly better in the experimental group than in the control group (P<0.05). The occlusal function between the affected side and contralateral side of both groups showed no significant difference 6, 12 and 36 months after treatment(P>0.05). CONCLUSIONS: All-ceramic onlay restoration of premolars has high success and survival rate, and good short-term and long-term restoration effect, which is beneficial to improve the occlusal function of the affected teeth. References | Related Articles | Metrics

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Effects of two implant systems on peri-implant soft tissue CAO Wei-yu, CAO Jie, LIU Bin-yi, XU Zhou 2022, 31 (3):  305-308.  doi: 10.19439/j.sjos.2022.03.016 Abstract ( 448 )   PDF (535KB) ( 158 )   PURPOSE: To investigate the effect of different implant systems on peri-implant soft tissue. METHODS: Forty patients requiring single implant therapy in posterior teeth at Dental and Ophthalmic Clinic of Putuo District from December 2020 to February 2021 were selected. Ten patients were implanted with bone level implants and 30 patients with soft tissue level implants. Periodontal exploration was performed at the buccal side, lingual side, mesial and distal axial angle of the implants, and the gingival crevicular fluid of these locations were taken to detect the enzyme level. The probing depth, aspartate aminotransferase (AST) and alkaline phosphatase (ALP) level of the two groups were compared at the day, 3 months, 6 months and 12 months after crown restoration. Statistical analysis was completed by SPSS 17.0 software package. RESULTS: The probing depth and ALP level of soft tissue level implants were significantly lower than those of bone level implants at the day, 3 months, 6 months and 12 months after crown restoration(P<0.05). At the day when crown restoration was accomplished, AST of soft tissue implant was significantly lower than that of bone level implant(P<0.05). AST in gingival crevicular fluid of bone level implants decreased rapidly in the following three time periods, and close to that of the soft tissue level implants(P>0.05) at last. CONCLUSIONS: Both bone level implants and soft tissue level implants have good clinical effects, but peri-implant soft tissues of the soft tissue level implants show better stability. References | Related Articles | Metrics

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Comparison of two-year stability between immediate implant action and delayed implantation for anterior teeth with periodontal disease ZHONG Lin, HE Chen-fei, WEI Ming-gui, LYU De-zhi, WANG Guo-shi, LI Shao-wei 2022, 31 (3):  309-312.  doi: 10.19439/j.sjos.2022.03.017 Abstract ( 310 )   PDF (486KB) ( 180 )   PURPOSE: To investigate the feasibility of immediate implantation after extraction of anterior teeth in patients with periodontal disease and its clinical effect within 2 years. METHODS: Thirty patients (36 implants) who underwent anterior dental implant treatment for periodontal disease from 2016 to 2018 were randomly divided into immediate implantation group (17 implants) and delayed implantation group (19 implants). The patients were followed up for 2 years, the clinical parameters such as periodontal probing depth, pink esthetic score（PES）and implant neck bone resorption volume of implant neck were obtained. The data was statistically analyzed with SPSS 21.0 software package. RESULTS: During the 2-year follow-up period, no implant loss, and there was no significant difference in the depth of peri-implant probing between the two groups at each time point(P>0.05). There was no significant difference in the volume of bone resorption at implant neck between the two groups(P>0.05). At 6, 12 and 24 months after completion of superstructure repair, there was no significant difference in pink esthetic score（PES）between the two groups (P>0.05), but there was significant difference in pink esthetic score（PES) at the third month after restoration (P<0.05). The immediate implantation group obtained more satisfactory soft tissue morphology around the implants. CONCLUSIONS: Under appropriate treatment conditions, there is no significant difference in implant success rate between immediate implantation and delayed implantation of anterior teeth in patients with periodontal disease. At the same time, it reduces the number of operations and shortens the course of treatment. In terms of soft tissue aesthetics, immediate implantation is slightly better than delayed implantation in the early stage after restoration, and can maintain a good soft tissue aesthetic effect. References | Related Articles | Metrics

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Clinical effect of digital impression combined with all-ceramic denture on restoration of 60 patients with dental defects CHEN Li-rong, LIANG Xue-jin, YANG Feng-ying, LUO Hao 2022, 31 (3):  313-317.  doi: 10.19439/j.sjos.2022.03.018 Abstract ( 251 )   PDF (760KB) ( 161 )   PURPOSE: To analyze the clinical effect of digital impression combined with all-ceramic denture restoration on patients with dental defects. METHODS: A study was conducted on 120 patients with dental defects admitted to Dongfeng Stomatological Hospital from June 2018 to June 2020. The two groups of patients were randomly divided into digital imprinting modules and silicone rubber imprinting modules using a random number table method. There were 60 cases in each group. The silicone rubber imprint module used traditional silicone impression combined with all-ceramic denture restoration, while the digital imprint module used digital impression combined with all-ceramic denture restoration.The clinical efficacy of the two groups was observed. Gingival index (GI), periodontal index (PI) before dental restoration, during dental restoration and 6 monthes after dental restoration were compared. The adjacent surface contact conditions, occlusion and adverse reactions of the two groups were compared. SPSS 22.0 software package was used for statistical analysis. RESULTS: The two groups of patients selected grade A and grade B for the evaluation of the restoration when the restoration was completed. The number of patients who chose grade A for the digital imprint module was more than that of the silicone rubber imprint module,but there was no significant difference(P>0.05). Six months after the tooth was worn, GI and PI indexes of the two groups of patients increased. GI and PI indexes of the silicone rubber stamping module were significantly higher than those of the digital stamping module(P<0.05). When dental restoration was completed and 6 months after the tooth was replaced, the pass rate of contact between the adjacent surfaces of the imprinting module patients was significantly higher than that of the silicone rubber imprinting module(P<0.05). When dental restoration was completed, the occlusion of the digital imprinting module patients was significantly better than that of the silicone rubber imprinting module(P<0.05). Six months after wearing the denture, there was no significant difference in occlusion between the two groups of patients(P>0.05). When dental models of the two groups of patients were taken, the incidence of adverse reactions in patients with digital imprints was significantly lower than that of silicone rubber imprints(P<0.05). CONCLUSIONS: The use of digital impressions combined with all-ceramic restorations to repair patients with dental defects can effectively improve the treatment effect, improve prognostic GI and PI indexes of the patients, increase the pass rate of the adjacent surface contact and occlusion of the tooth, and reduce the process of dental restoration. The incidence of adverse reactions are minimal, with good prognostic effects. It is worthy of clinical application. References | Related Articles | Metrics

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Comparative study on the effect of microscopic revascularization and apexification in the treatment of pulp necrosis of permanent teeth LIN Xiao-ming, SU Jiang-ling, PU Cui-ping 2022, 31 (3):  318-321.  doi: 10.19439/j.sjos.2022.03.019 Abstract ( 529 )   PDF (564KB) ( 260 )   PURPOSE: To compare the curative effect of microscopic revascularization and apexification in the treatment of pulp necrosis of permanent teeth. METHODS: Seventy-five cases of pulp necrosis in young permanent teeth were divided into two groups according to different treatment methods. Group A (n=30) underwent revascularization under microscope, while group B (n=45) underwent apexification. The treatment effect and pain improvement of the two groups were compared. The changes of the wall thickness and root canal length of the affected teeth before and after treatment were observed, and the bone-like deposition rate after treatment was recorded. SPSS 23.0 software package was used for statistical analysis. RESULTS: There was no significant difference in the length of root canal between the two groups before treatment (P>0.05); there was no significant difference in the length of root canal in group B before and after treatment (P>0.05); the length of root canal in group A was significantly longer than that in group B 6 months after treatment(P<0.05). There was no significant change in the thickness of root canal wall in group B before and after treatment (P>0.05). The thickness of root canal in group A was significantly higher than that in group A 6 months after treatment (P<0.05). Bone-like deposition rate of group A was significantly higher than that of group B 1 month and 6 months after treatment (P<0.05). The total effective rate of group A and B was 90.00% and 84.44%, the difference was not statistically significant (P>0.05). The cure rate of group A was 70.00%, which was significantly higher than that of group B (48.89%, P<0.05). COCLUSIONS: Microscopic revascularization for pulp necrosis of young permanent teeth can effectively promote root development, lengthen root canal and increase the thickness of canal wall, which is better than apexification. References | Related Articles | Metrics

Clinical Reports

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MRI findings of parotid acinic cell carcinoma in 19 consecutive cases XIAO Hua, TAO Xiao-feng, ZHU Wen-jing, CHEN Qian-qian 2022, 31 (3):  322-326.  doi: 10.19439/j.sjos.2022.03.020 Abstract ( 461 )   PDF (1403KB) ( 179 )   PURPOSE: To describe the MRI features of acinar cell carcinoma of parotid gland (AciCC) and to evaluate the diagnostic value of MR functional imaging. METHODS: A total of 269 cases of maxillofacial AciCC confirmed by surgery and pathology were analyzed. Among them, nineteen subjects with AciCC in the parotid gland underwent preoperative MRI examination (non-enhanced scan for one case, enhanced scan for 18 cases), seventeen patients underwent diffusion-weighted imaging scan, and 15 patients underwent dynamic contrast-enhanced scan. MRI findings of 19 patients were retrospectively analyzed. The lesion size, location, morphology, margin, internal composition, enhancement pattern and functional imaging characteristics were analyzed. SPSS 25.0 software package was used for statistical analysis. RESULTS: Among 269 cases of maxillofacial AciCC, there were 108 males and 161 females, male: female = 1:1.49, aged from 4 to 89 years, with a mean age of (45.95±17.33) years. 84.4% (227/269) were located in the parotid gland. On MRI images, 78.9% (15/19) had well-defined margin, 57.9% (11/19) were round or oval, and 36.8% (7/19) were lobed nodules. One case had irregular morphology and peripheral invasion. The range of maximum diameter was 6-56 mm, averaging (24.8±15.3) mm. Internal composition showed 57.9% (11/19) were cystic solid, 42.1% (8/19) were solid, 31.6% (6/19) had bleeding. T2-weighted MRI showed 52.6% (10/19) with envelope structure, 15.8% (3/19) with low signal separation inside, 38.9%(7/18) had uniform enhancement, and 61.1%(11/18) had uneven enhancement. Functional imaging showed the mean ADC value of tumor was (1.026±0.194)×10-3 mm2/s(n=17). 86.7%(13/15) TIC was type Ⅱ. CONCLUSIONS: Most maxillofacial AciCC are located in the parotid gland. It is difficult to distinguish AciCC from benign tumors with conventional MRI in morphology. The ADC value of AciCC is lower than that of benign tumors, and the type of TIC curve is mostly type Ⅱ. Combination of morphology and functional imaging can improve the diagnostic accuracy of this disease. References | Related Articles | Metrics

Dental Education

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Evaluation of the method to predict the difficulty of the test questions in a national dental board examination WANG Ning, HUANG Rong, ZHANG Quan-hui 2022, 31 (3):  327-329.  doi: 10.19439/j.sjos.2022.03.021 Abstract ( 242 )   PDF (360KB) ( 185 )   PURPOSE: To explore a possible method of improving prediction by analyzing the effect and influencial factors of difficulty prediction of a national board dental examinations. METHODS: The correlation between the predicted value and the measured value, and related influential factors were analyzed with SPSS 16.0 software package. RESULTS: The correlation between the predicted difficulty and the tested difficulty increased after the improvement of the method (P<0.05). The correlation was mainly reflected in the median score group of candidates. CONCLUSIONS: Improving the method of difficulty prediction can increase the prediction effect, and it is helpful to improve the forecasting ability of the test paper and to evaluate the candidates accurately. References | Related Articles | Metrics

Systematic Review

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Psychological intervention for negative emotion and quality of life of patients with head and neck cancer (HNC): a meta-analysis XIA Jia-lin, ZENG Yi-wei, ZHAO Xiao-mei, HOU Li-li 2022, 31 (3):  330-336.  doi: 10.19439/j.sjos.2022.03.022 Abstract ( 220 )   PDF (1740KB) ( 219 )   PURPOSE: To systematically assess the efficacy of psychological intervention for patients with head and neck cancer (HNC) in easing negative emotion and improving quality of life, so as to provide evidence-based reference for clinical psycho-intervention of HNC patients. METHODS: PubMed, Central, Embase, clinicaltrials.gov, ICTRP, Web of science, CBM, CNKI, VIP, and Wan Fang database were searched from inception to 15th, May for randomized controlled trails conducted to assess psychological intervention for HNC patients. The retrieval, screening, quality evaluation, and data extraction were elaborately proceeded by two reviewers independently. Meta analysis was performed using RevMan 5.4 software. RESULTS: Eighteen RCTs were included with 2 097 participants. Meta analysis showed that compared to control group, psychological intervention group manifested greater decrease in anxiety scores [SMD=-2.33, 95%CI（-2.96,-1.70）, P<0.000 01] and depression scores [SMD=-2.26, 95%CI（-2.78,-1.74）, P<0.000 01], and better increase in QOL scores [SMD=6.04, 95%CI（1.53,10.56）, P=0.009] and SQL-90 scores [MD=29.99, 95%CI（-36.22, -23.76）,P<0.000 01]. CONCLUSIONS: The anxiety and depression of HNC patients can be effectively relieved through psychological intervention, so that their quality of life and metal health status can be improved. Due to the limitation of quality of included RCT , the result remains to be further validated by more well-designed and better-qualified study. References | Related Articles | Metrics