Current Issue
01 August 2022, Volume 40 Issue 4
  • Core scientific issues of orthodontic tooth movement: position objective, efficiency, and accuracy
    Zhao Zhihe, Jin Zuolin, Bai Yuxing, Fang Bing, Bai Ding, Li Weiran, He Hong, Hu Min, Liu Yuehua, Chen Lili, Song Jinlin, Cao Yang, Li Yu, Shu Rui
    West China Journal of Stomatology. 2022, 40(4):  371-376.  doi:10.7518/hxkq.2022.04.001
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    Although the current technical systems of orthodontic tooth movement are practically mature, a noticeable gap still exists between the overall treatment results and the expectations. According to literature review, orthodontic tooth movement involves three core scientific issues, i.e., position objective, efficiency, and accuracy. Research concerning these three issues is the key to further improve orthodontic treatment outcomes and promote progress of the subject orthodontics.

    Receptor activator of nuclear factor-κB ligand and tumor necrosis factor-α promotes osteoclast differentiation through the exosomes of inflammatory periodontal ligament stem cells
    Dai Zhenning, Zheng Weihan, Li Shiyu
    West China Journal of Stomatology. 2022, 40(4):  377-385.  doi:10.7518/hxkq.2022.04.002
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    Objective Pathological bone resorption is common in chronic periodontitis. However, the effect of exosomes (Exo) secreted by periodontal ligament stem cells (PDLSCs) on bone resorption is unclear. This study explored the Exo of inflammatory PDLSCs, their protein components, and their effects on osteoclast differentiation. Methods PDLSCs were isolated from the periodontal ligament tissues of orthodontic patients and those with chronic periodontitis. The surface markers of PDLSCs were detected by flow cytometry. Exo were characterized by Western blot, transmission electron microscope (TEM), bicinchoninic acid assay (BCA), nanosight tracking analysis (NTA). The protein components of Exo were detected by protein profiling. The expression levels of differentially expressed proteins tumor necrosis factor-α (TNF-α), receptor activator of nuclear factor-κB ligand (RANKL), interleukin (IL)-1α, transforming growth factor β (TGF-β), and bone morphogenetic protein 2 (BMP-2) were verified by enzyme linked immunosorbent assay (ELISA). Then, 10, 100, and 1 000 μg·mL-1 of Exo-CP or Exo-WT were added to RAW264.7 medium, and the expression levels of osteoclast-related indicators were detected by real time quantitative polymerase chain reaction (RT-qPCR), Western blot, and tartrate resistant acid phosphatase (TRAP) staining at 5 days. Experimental data were statistically analyzed using SPSS 24.0 software. Results The differentially expressed proteins enriched in Exo-CP were mainly related to the tumor necrosis factor (TNF) signaling, osteoclast differentiation, and nuclear transcription factor κB (NF-κB) signaling pathways. ELISA experiments confirmed Exo-CP had high expression of TNF-α, RANKL, and IL-1α and low expression of TGF-β1 and BMP-2 (P<0.05). Adding Exo-CP to RAW264.7 significantly increased the expression of mRNA and proteins related to osteoclast differentiation of cells. In a concentration-dependent manner, the effect of Exo-CP on osteoclast differentiation at concentrations of 100 and 1 000 μg·mL-1 was significantly higher than that on the 10 μg·mL-1 concentration group (P<0.05). Conclusion Pathological bone resorption of chronic periodontitis may be caused by the activation of Exo-CP to promote osteoclast differentiation. The main protein in Exo may be RANKL and TNF-α. This research provides a new perspective on pathological bone resorption in chronic periodontitis.

    Effect of microRNA-663b on migration, invasion and epithelial‑mesenchymal transition of oral squamous cell carcinoma cells
    Cong Biqiao, Liu Xiaoping, Chen Jiawen, Li Hongli, Fan Xin
    West China Journal of Stomatology. 2022, 40(4):  386-393.  doi:10.7518/hxkq.2022.04.003
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    Objective To explore the effect of microRNA-663b (miR-6636) on migration, invasion and epithelial-mesenchymal transition (EMT) of oral squamous cell carcinoma cells (OSCC). Methods Use R Studio of gene expression omnibus (GEO) database to analyze expressions of miR-663b in the OSCC and adjacent normal tissues. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of miR-663b in tissues and cells. The transfection efficiency of HN30 cells with miR-663b knockout plasmid was detected. Transwell assay was used to detect the effect of the migration and invasion ability. Bioinformatics method was used to predict the targeted mRNA that may bind to miR-663b and double luciferase assay was used to verify the binding. Western blot assay was used to detect the expression of EMT-related markers. Results The expression of miR-663b was up-regulated in OSCC tissues and higher in HN30, CAL27 and SCC-9 cells than in HOEC cells (P<0.05). Knockout of miR-663b could inhibit migration and invasion of HN30 cells (P<0.05) and inhibit the occurrence of EMT. Bioinformatics prediction software predicts that SH3BP2 was the target gene of miR-663b, and patients with low SH3BP2 expression had a poor prognosis (P<0.05). MiR-663b could bind to SHBP2 (P<0.05). The expression of SH3BP2 was increased and the occurrence of EMT was inhibited in HN30 cells with miR-663b knocked out. Conclusion Knockout of miR-663b can inhibit the migration, invasion and EMT of OSCC by targeting SH3BP2.

    Effects of silencing farnesyltransferase on the migration, invasion, and epithelial-mesenchymal transition of salivary adenoid cystic carcinoma cells
    Li Wenjian, Tong Lei, Wang Qimin, Han Hongyu, Chen Zhenggang
    West China Journal of Stomatology. 2022, 40(4):  394-402.  doi:10.7518/hxkq.2022.04.004
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    Objective This study aimed to investigate the effects of farnesyltransferase (FTase) on the migration, invasion, and epithelial-mesenchymal transition (EMT) of SACC-LM and SACC-83 cells in salivary adenoid cystic carcinoma and determine the relative mechanism. Methods Three small interfering RNA (siRNA) sequences were designed and constructed based on the human FTase gene sequence. The SACC-LM and SACC-83 cells in the logarithmic growth period were used, and the expression of FTase was suppressed by liposomal transient transfection. The tested cells were categorized as the FTase-siRNA-1, FTase-siRNA-2, and FTase-siRNA-3 groups. Both negative control group (NC-siRNA) and blank control group (only transfection reagent was added) were set. The mRNA expression of FTase and HRAS was detected by quantitive real-time polymerase chain reaction, and the silencing efficiency was determined. The expression levels of FTase, HRAS, protein kinase B (AKT), phospho-AKT, p65, phospho-p65 (Ser563), E-cadherin, vimentin, matrix metalloproteinase (MMP)-9 protein, and HRAS membrane protein were detected by Western blot. Transwell assay and wound healing assay were used to detect the invasion and migration abilities of cells. Results The relative expression of FTase mRNA and protein in the FTase-siRNA-1 group decreased compared with those in the control group (P<0.05). HRAS mRNA and total protein expression had no significant difference (P>0.05), and the relative expression of HRAS membrane protein decreased (P<0.05). The relative expression of E-cadherin increased (P<0.05), vimentin decreased (P<0.05), and MMP-9 decreased (P<0.05). There was no significant difference in the relative expression levels of the RAS/PI3K/AKT/nuclear factor-κB signaling pathway-related proteins AKT and p65 (P>0.05), but the relative expression levels of phospho-AKT and phospho-p65 decreased. The invasion and migration ability of the FTase-siRNA-1 group significantly decreased compared with that in the control group (P<0.05). Conclusion Silencing FTase in vitro could effectively inhibit the invasion and migration of SACC-LM and SACC-83 cells by interfering with the localization of the HRAS membrane protein and regulating the RAS/PI3K/AKT/nuclear factor-κB signaling pathway to mediate EMT.

    Effect of core and veneer porcelain thickness and resin cement on opalescence property of glass-ceramic veneers
    Li Zhemin, Ma Wenjie, Yang Shuran, Yang Qiusong, Wang Jianing, Yao Zhangshun, Lin Yunhong, Li Xingxing
    West China Journal of Stomatology. 2022, 40(4):  403-408.  doi:10.7518/hxkq.2022.04.005
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    Objective This study aimed to analyze the effect of core and veneer porcelain thickness and resin cement on the opalescence property (OP) of glass-ceramic veneers, which were used to restore discolored teeth. Methods IPS e.max CAD LT A3 ceramic specimens were fabricated by computer aided design and computer aided manufacturing (CAD/CAM). The thickness values of core porcelain groups were 0.25 and 0.50 mm, and those of the core/veneer porcelain groups were 0.25 mm core/0.25 mm dentin, 0.50 mm core/0.25 mm dentin, 0.50 mm core/0.50 mm dentin, and 0.50 mm core/0.25 mm dentin/0.25 mm incisal. To simulate the clinical bonding procedure of porcelain veneer, resin cement Variolink N Bleach XL was coated at the bottom of CAD/CAM porcelain veneer specimens to make composite specimens of CAD/CAM porcelain veneer and resin cement. The L*a*b* values of specimens in the reflection and transmission pattern were measured by a spectrophotometer. Then, the OP was calculated. Results The OP values of 0.25 and 0.50 mm core porcelain groups, and 0.25 mm core/0.25 mm dentin, 0.50 mm core/0.25 mm dentin, 0.50 mm core/0.50 mm dentin, and 0.50 mm core/0.25 mm dentin/0.25 mm incisal core/veneer porcelain groups were 6.10±0.50, 7.00±0.24, 6.40±0.24, 7.08±0.28, 7.16±0.21, and 7.86±0.11 respectively. With increasing thickness of core porcelain, the OP values increased significantly (P<0.05). When 0.25 mm-thick dentin porcelain was added, no significant difference was found in the OP values of specimens with the same core porcelain thickness (P>0.05). For the 0.50 mm core porcelain group, no significant difference was found between 0.25 and 0.50 mm-thick dentin porcelain groups (P>0.05), but the OP values increased significantly after increasing the 0.25 mm incisal porcelain (P<0.05). The OP values of 0.25 mm core/0.25 mm dentin, 0.50 mm core/0.25 mm dentin, 0.50 mm core/0.50 mm dentin, and 0.50 mm core/0.25 mm dentin/0.25 mm incisal CAD/CAM porcelain veneer-resin cement composite specimens were 6.29±0.31, 7.56±0.36, 7.67±0.30, and 8.65±0.53. The OP values increased with increasing thickness of the porcelain layer (P<0.05), but no statistically signi-ficant difference was found between the groups of 0.50 mm core/0.25 mm dentin and 0.50 mm core/0.50 mm dentin (P=0.733). The influence of porcelain layer thickness and resin cement on the OP value was statistically different (P<0.05), and no interaction was found between the total thickness and the presence of resin cement (P>0.05). Conclusion When using glass-ceramic veneers for discolored teeth, the following are recommended to improve the OP and obtain a natural and realistic effect: adopt the design of direct sintering incisal porcelain with core porcelain; appropriately increase the thickness of core porcelain; and select resin cement with opaque effect.

    Settling effect of abutment and torque loss in different types of abutment after cyclic loading
    Shen Qinyuan, Huang Min, Wei Junchao, Zhang Qi, Wu Runfa.
    West China Journal of Stomatology. 2022, 40(4):  409-413.  doi:10.7518/hxkq.2022.04.006
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    Objective This study aimed to evaluate and compare the settling effect of implant-abutment assembly and the torque loss before and after cyclic loading in three types of abutments. Methods Thirty internal hexagon fixtures were randomly divided into three groups (n=10). Group A used original abutments, group B used pre-machined cast abutments, and group C used compatible abutments. In addition, the abutment morse taper angle was measured using an image measuring instrument. Removal torque values (RTVs) were recorded using a digital torque meter before and after cyclic loading. All samples were tested in a universal testing machine with a vertical load between 0 and 250 N for 100 000 cycles of 10 Hz. The settling effect was measured after cyclic loading. Paired t test was performed for intragroup analysis of removal torque loss before and after cycling and one-way ANOVA. Subsequently, Tukey’s honestly significant difference test was used for intergroup comparison (α=0.05). Results The paired t-test showed signi⁃ficant differences in the intragroup RTVs before and after cycling (P<0.001). ANOVA showed significant differences in the mean of removal torque loss after cycling (P=0.009), the abutment morse taper angle (P<0.001), and the settling values (P=0.01) among different groups. However, no significant difference was found between compatible abutments and pre-machined cast abutments. Conclusion The screw removal torque was significantly reduced for all groups in this study after cyclic loading. Differences could be found in the internal accuracy of implant-abutment assembly among different groups. Within the limitations of this study, the results showed the original abutments exhibited lower percentages of torque reduction after cyclic loading than the casting abutments and the compatible abutments.

    Association between bone morphology and sagittal disc position in temporomandibular joints of patients with anterior disc displacement
    Yan Li, Zhou Maoqiang, Qiu Jiaxuan
    West China Journal of Stomatology. 2022, 40(4):  414-421.  doi:10.7518/hxkq.2022.04.007
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    Objective To analyze the association between sagittal temporomandibular joint (TMJ) disc position of patients with anterior disc displacement evaluated by magnetic resonance imaging (MRI) and bone morphology of the TMJ evaluated by cone-beam computed tomography (CBCT). Methods One hundred and seventy-eight TMJs of 97 patients were retrospectively analyzed. The TMJ disc position was evaluated using MRI and classified into four types: control group (without disc displacement), slight group (disc slightly anteriorly displaced), moderate group (disc moderately anteriorly displaced), and severe group (disc severely anteriorly displaced). The measurements of TMJ bone morphology among four groups were evaluated by CBCT through Mimics software including condyle linear dimensions (condyle length, width, and height), condylar volume and surface area, and the depth and length of the glenoid fossa, joint anterior space, joint superior space, and joint posterior space. The sagittal plane position of the condyle was also assessed. The differences in all the morphologic measurement parameters among the four groups were detected using the one-way analysis of variance or the Kruskal Wallis test, and Chi-square tests. The correlations between disc sagittal position and all the morphologic measurements were also analyzed. Results There were significant differences in measurements of condyle linear dimensions, condylar volume and surface area, depth of the glenoid fossa, joint spaces, and distribution of the condyle sagittal positions among the four groups. By contrast, there were no statistical differences in terms of the length of the glenoid fossa among the four groups. Correlation analysis revealed that there is a statistically significant negative correlation among condyle linear dimensions, condylar volume and surface area, the depth of the glenoid fossa, joint superior space, and disc position. However, joint posterior space was positively correlated with disc position. Conclusion A statistically significant correlation was determined between TMJ bone morphology and different sagittal disc positions. Degenerative changes in TMJ bone morphology clinically diagnosed should be altered, which can be the patients' marker of anterior disc displacement.

    Clinical study on the pattern of lower-level lymphatic metastasis in primary tongue squamous cell carcinoma
    Yang Yunbo, Han Nannan, Wang Yupu, Li Huasheng, Yan Ming, Li Siyi, Ruan Min, Zhang Chenping
    West China Journal of Stomatology. 2022, 40(4):  422-427.  doi:10.7518/hxkq.2022.04.008
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    Objective To study and analyze the clinical patterns of lower-level lymph node (Ⅳ and Ⅴ) metastasis in primary tongue squamous cell carcinoma, and establish a reference for the decision-making of the lower-level neck dissection in tongue squamous cell carcinoma. Methods A total of 203 patients with primary tongue squamous cell carcinoma were recruited. These patients underwent simultaneous/secondary comprehensive neck (level Ⅰ-Ⅴ) dissection in Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine from January 2010 to December 2015. Their clinicopathological and follow-up data were obtained and analyzed to reveal the prognosis and risk factors of primary tongue squamous cell carcinoma with lower-level lymph node metastasis. Results Among the 203 patients, the metastasis rates of levels Ⅳ and Ⅴ are 14.78% and 4.93%, respectively. Level Ⅳ metastasis is more prevalent in males than females (P=0.04); non-smokers are more likely to have level Ⅴ metastasis than smokers (P=0.046). Lymph node status in levels Ⅲ and Ⅳ are significantly associated with the risk of metastasis in level Ⅴ (P=0.001). Patients with extracapsular invasion in level Ⅲ have a significantly increased risk of metastasis in levels Ⅳ (P=0.014) and Ⅴ (P=0.026). The 5-year survival rate of patients with lower lymph node (Ⅳ/Ⅴ) metastasis is only 14.70%, which is an independent poor prognostic factor for patients with primary tongue squamous cell carcinoma (P<0.000 1). Conclusion Most primary tongue squamous cell carcinoma metastases occur in levels Ⅰ-Ⅲ. However, the rate of lower-level lymph node metastasis is rather low. For the cN0 and cN+ patients with levels Ⅰ-Ⅱ lymph node metastases without extracapsular invasion, the strategy for level Ⅴ management may be observation rather than dissection.

    Effects of loupes and microscopes on a dental technician’s working posture from ergonomic aspects
    Yu Jiayi, Lou Yuxin, Zhu Liqing, Ren Wei, Yang Xingqiang, Yu Haiyang.
    West China Journal of Stomatology. 2022, 40(4):  428-435.  doi:10.7518/hxkq.2022.04.009
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    Objective This work aimed to study the effects of loupes and microscopes on a dental technician’s working posture during practical operation from ergonomic aspects. The technician's working postures under the conditions of the naked eye, loupes, and microscopes were compared. The practical value of loupes and microscopes was assessed based on the evaluation index of working posture from ergonomic aspects. Methods Three dental technicians who were skilled in using loupes and microscopes from West China Stomatology Technology Department of Sichuan University were involved in this prospective rando-mized controlled trial. Before the operation, cameras were installed in the sagittal position, top-view position, and dorsal position of the operation. Each technician made five porcelain veneers of the right maxillary central incisor following the standard process. A chairside computer-aided design and computer-aided manufacturing (CAD/CAM) system was used to mill and layer the ceramic block under the naked eye (A: control group), 3.5× headwear loupes (B: loupe group), and 9× desktop microscopes (C: microscope group). The working posture was recorded by videos throughout the entire process. After each operation, the investigator used OpenPose to recognize the working posture. The joint angles of the arm, elbow, wrist, neck, and trunk, as well as their corresponding rapid upper limb assessment (RULA) scores, were calcula-ted by MATLAB. The working posture was assessed from ergonomic aspects based on the joint angles, RULA scores, and operation time. Statistical analysis was performed using SPSS 26.0. Results The RULA score of upper limb joint angles showed that the angles of the arm, elbow, wrist, neck, and trunk under the naked eye were 14.93°±9.44°, 120.19°±2.99°, 23.97°±2.84°, 47.27°±5.72°, and 7.76°±2.30°, respectively. All of the joint angles were significantly different among the three groups (P<0.05). Compared with the control group, the angles of the neck and trunk in the loupe group were reduced by 29.09% and 42.53%, respectively, whereas those in the microscope group were significantly reduced by 43.99% and 87.11%, respectively. Multiple comparisons by LSD for the angles of neck and trunk revealed that the loupe group and the microscope group were significantly different from the control group (P<0.05), and they were also significantly different from each other (P<0.05). The mean RULA scores were 6.24±0.34 in the control group, 5.53±0.35 in the loupe group, and 3.31±0.19 in the microscope group. Compared with the control group, the mean RULA score in the loupe group was lower, and that in the microscope group was significantly lower. The differences between every two groups were statistically significant (P<0.05). The mean RULA score in the microscope group was significantly lower than that in the loupe group (P<0.05). The average operation times of the control group, loupe group, and microscope group were (50.69±36.78), (52.01±34.65), and (59.44±35.81) min, respectively. No significant difference was found among the three groups (P>0.05). Conclusion Use of loupes and microscopes showed an improvement in ergonomics and working posture of dental technicians. Microscopes had a better effect in the ergonomic convenience of the technician than loupes.

    Clinical application of double eyelid incision in internal fixation of zygomatic-frontal fracture
    Feng Dajun, Xu Peng, Sun Yunfeng.
    West China Journal of Stomatology. 2022, 40(4):  436-439.  doi:10.7518/hxkq.2022.04.010
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    Objective This study aimed to investigate the clinical application effect of double eyelid incision in the internal fixation of suturae zygomatico-frontalis fracture. Methods A total of 12 patients with zygomatic complex fracture and evident fracture segment displacement, accompanied by facial collapse or mouth opening limitation and other functional disorders, were selected for open reduction and internal fixation. The suturae zygomatico-frontalis fracture was fixed using a double eyelid approach. Postoperative evaluation was performed on fracture reduction and fixation to evaluate the improvement of function and deformity, postoperative scar, and other conditions. Results All fractures had convenient reduction and fixation, and all patients had satisfactory facial appearance, evident functional improvement, and hidden postoperative scar. Conclusion As a surgical approach to reduce and internally fix zygomatic complex fracture, double eyelid incision can reduce not only the fracture, but also the trauma, thereby indicating its certain clinical value.

    Evaluation and influencing factors of oral health-related quality of life of middle-aged and elderly in Chengdu
    Wu Kan, Li Weiming, Zhong Yisi, Cheng Li, Tang Tian, Yin Wei.
    West China Journal of Stomatology. 2022, 40(4):  440-445.  doi:10.7518/hxkq.2022.04.011
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    Objective This study aimed to investigate the oral health-related quality of life of middle-aged and elderly in Chengdu and analyze the influencing factors. Methods Six hundred middle-aged and elderly people in Chengdu were randomly selected, and their demographic and social characteristics, general health status, oral health behavior, and other information were investigated. The oral health-related quality of life of these individuals was evaluated using the oral health impact profile (OHIP-14). Results The score of oral health-related quality of life was 3.91±6.67, and regression analysis results indicated that its influencing factors included income level (OR=0.387, P<0.05), chronic diseases (OR=0.665, P<0.05), oral diseases (OR=0.260, P<0.05), self-evaluation of mental health status (OR=0.338, P<0.05), brushing teeth twice a day (OR=1.846, P<0.05), smoking (OR=0.566, P<0.05), oral health awareness (OR=2.431, P<0.05), and convenience of medical treatment (OR=0.499, P<0.05). Conclusion Oral health-related quality of life is affected by multiple factors. Comprehensive oral intervention measures should be actively carried out to improve the oral health behavior of residents and oral health-related quality of life of middle-aged and elderly people in communities.

    Radiofrequency thermocoagulation combined with doxorubicin injection for treatment of trigeminal neuralgia mandibular branch
    Zhang Lingge, Li Jie, Li Jihong, Tang Hongchao, Liu Yuxue
    West China Journal of Stomatology. 2022, 40(4):  446-450.  doi:10.7518/hxkq.2022.04.012
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    Objective This study aimed to evaluate the clinical application value of 3D printed template-guided radiofrequency thermocoagulation combined with doxorubicin injection for the treatment of trigeminal neuralgia mandibular branch. Methods A total of 50 patients with primary trigeminal neuralgia mandibular branch in the hospital from January 2019 to September 2020 were randomly divided into two groups: 3D printed template-guided radiofrequency thermocoagulation combined with doxorubicin injection was used as the research group (n=25), and 3D printed template guided radiofrequency thermocoagulation was used as the control group (n=25). Comparative analysis of visual analogue score (VAS) was conducted before and immediately after surgery and at 1, 3, 6, and 12 months after surgery. The Brisman efficacy evaluation criteria for trigeminal neuralgia was used to evaluate the therapeutic effect of each postoperative follow-up period, and postoperative complications were observed. Results The VAS immediately after surgery and at 1, 3, 6, and 12 months after surgery in the two groups was significantly lower than that before surgery, with statistical significance (P<0.05). According to Brisman efficacy evaluation criteria for trigeminal neuralgia, no significant difference was found in the efficacy between the two groups at 1 and 3 months after surgery (P>0.05). At 6 and 12 months postoperatively, the effectiveness of the research group was higher than that of the control group, and the differences were statistically significant (P<0.05). In the research group, no recurrence occurred during the follow-up period, whereas in the control group, one, two, and four recurrences occurred 3, 6, and 12 months after surgery, respectively. No obvious complications were found in both groups. Conclusion 3D printed template-guided radiofrequency thermocoagulation combined with doxorubicin injection for the treatment of trigeminal neuralgia mandibular branch could enhance the long-term curative effect and reduce the recurrence rate, thus worthy of clinical promotion and application.

    Comparative study on the effect of maxillary expansion on the displacement of maxillary alveolar bone before and after alveolar bone graft: a three-dimensional finite element analysis
    Yuan Wei, Hou Yan, Song Peng, Zhang Xiaohuan, Huang Wei
    West China Journal of Stomatology. 2022, 40(4):  451-456.  doi:10.7518/hxkq.2022.04.013
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    Objective This paper aimed to simulate and compare the effect of maxillary expansion on the displacement of maxillary alveolar bone before and after alveolar bone graft. Methods On the established finite element model of the maxilla before bone grafting, ANSYS was used to simulate alveolar bone graft to form the model of maxilla after bone grafting. The same expansion force was applied to the two models, and the three-dimensional displacement of alveolar bone was observed and compared between them. Results Comparison of the three-dimensional displacement showed that expansion before bone grafting was significantly larger than that after bone grafting (P<0.05). For horizontal displacement, in the expansion group before bone grafting, the displacement was gradually decreased from anterior to posterior alveolar bone. In the expansion group after bone grafting, the displacement was gradually increased from anterior to posterior alveolar bone. Displacement of noncleft side alveolar bone was significantly larger than that of cleft side alveolar bone with maxillary expansion before and after alveolar bone graft (P<0.05). In terms of vertical displacement, the anteromedial alveolar bone moved downward and the posterolateral alveolar bone moved upward with maxillary expansion before and after alveolar bone graft. For sagittal displacement, the anteromedial alveolar bone moved forward and the posterolateral alveolar bone moved backward with maxillary expansion before alveolar bone graft. However, the movement trend was opposite with maxillary expansion after alveolar bone graft. Conclusion The three-dimensional movement with maxillary expansion before alveolar bone graft is more obvious than that after bone grafting for patients with unilateral complete cleft lip and palate. Expander should be moved backward properly with maxillary expansion before alveolar bone graft and moved forward properly and cooperated with maxillary protraction with maxillary expansion after alveolar bone graft. Meanwhile, precaution must be taken in terms of asymmetric expansion and anterior open bite in operation.

    Occlusal analysis of patients with chewing side preference and symptoms of temporomandibular disorders
    Zhang Qiao, Huang Dongzong, Zhai Xiaoting, Li Hongbo, Hu Min, Liu Hongchen, Jiang Hua
    West China Journal of Stomatology. 2022, 40(4):  457-467.  doi:10.7518/hxkq.2022.04.014
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    Objective In this study, TeeTester digital occlusal analysis system was used to analyse the occlusal characteristics of chewing side preference (CSP) and non-CSP patients with TMD symptoms. Methods According to the questionnaire and oral examination, 80 subjects were screened and divided into four groups: 20 CSP patients with TMD symptoms, 20 CSP patients without TMD symptoms, 20 non-CSP patients with TMD symptoms, 20 non-CSP patients without TMD symptoms. TeeTester digital occlusal system was applied to measure the occlusal characteristics in all four groups, including total contect area (TCA), total occlution force (TOF), distribution of occlusal force (DOF), asymmetric index of occlusal force (AOF), occlusal time (OT), disclusion time (DT) and center of occlusal force(COF). SPSS 25.0 was used to analyze the statistical data. Results At intercuspal position, the data reveals significant differences in the maximum TOF and TCA among the four groups (P<0.05). There was significant difference in the distribution of occlusal force between the preferred side and the other side of CSP patients with or without TMD symptoms (P<0.05). Among the four groups, there were statistically significant difference in the position of the center point of occlusal force, the direction of the center point of occlusal force, and the vertical distance between the center point of occlusal force and the center line (P<0.05). The COF, maximum TOF and TCA of the preferred side of dentition were significantly positive correla⁃ted with CSP (P<0.05), according to Spearman correlation analysis. However, the maximum TOF and TCA of the both side of dentition were significantly negative correlated with TMD symptoms (P<0.05). Conclusion 1) The occlusal characteristics of CSP patients and non-CSP patients with TMD symptoms are different. TeeTester digital occlusal analysis system provides objective parameters for the dynamic evaluation of occlusion. 2) Among all the occlusal cha⁃racteristics, maximum TOF, TCA and COF of the preferred side of dentition were positively correlated with CSP. The abnormal occlusal characteristics (maximum TOF and TCA of the whole dentition) caused by CSP are related to TMD symptoms.

    Application of visualization technology of multimode data fusion in occlusal rehabilitation
    Sun Xinrong, Feng Yue, Liu Weicai.
    West China Journal of Stomatology. 2022, 40(4):  468-475.  doi:10.7518/hxkq.2022.04.015
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    Objective This study aimed to present a method for multi-modal medical data fusion that could be used for increased vertical dimension of occlusion (VDO) and occlusal rehabilitation in a digital manner, thus facilitating the process of clinical diagnosis and restoration. Methods With the aid of a computer software, a visual and operable four-dimensional virtual dental patient was created by data fusion of intraoral scan, extra-oral face scan, cone-beam computed tomography, and dynamic occlusal movement trace to conduct a systematical review of the occlusion and temporomandibular joint of the virtual patient. This approach could be used for increased VDO on the basis of the aesthetics of anterior teeth and the restoration space of posterior teeth. It allowed jaw reconstruction and occlusal rehabilitation with fixed prosthesis by using computer-aided design and manufacturing (CAD/CAM) devices. Results A visual and operable four-dimensional virtual dental patient was created by integrating the method for multimodal medical data fusion with CAD/CAM devices, thus making the process of occlusal rehabilitation with fixed prosthesis safer and more convenient than before. Conclusion With the method for multimodal medical data fusion, the presented application enables the fusion of different data sources of the patient at the same time and space by creating a virtual patient. It is useful for showing the function and anatomical structure of the patient’s oral and maxillofacial system in a visual and convenient manner, thus providing a powerful tool in the process of clinical diagnosis and restoration.

    Two cases of bilateral coronoid process hyperplasia causing restricted mouth opening
    Zhang Yanyan, Liu Fei, Shen Jiefei, Li Xiaoqing
    West China Journal of Stomatology. 2022, 40(4):  476-482.  doi:10.7518/hxkq.2022.04.016
    Abstract ( 89 )   HTML ( 13 )   PDF(pc) (6812KB) ( 38 )   Save
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    Coronoid process hyperplasia (CPH) is a rare condition characterized by the increase in the size of the coronoid process, mainly occurring in the second decades of human life. To provide a reference for the diagnosis and treatment of this disease, we reported the clinical manifestations of two cases, X-ray examination, treatment, and prognosis with mandibular movement and restricted mouth opening (RMO) caused by bilateral CPH. The opening degree of the two cases described in the article increased to almost 40 mm immediately after the elongated coronoid process was surgically removed and a case was maintained normal after 2 months. In another case, CPH recurred after 2 years of follow-up. The etiology of CPH is still unclear, which is associated with various factors. RMO caused by CPH is extremely rare in clinical practice, and it is easy for patients to get confused and be misdiagnosed. It should be diagnosed using comprehensive methods of clinical studies and imaging modalities. Currently, surgical coronoidectomy is an accepted treatment of CPH. Long-term effective opening training is crucial in maintaining its therapeutic effect.

    Non-syndromic familial congenital dental deficiency: two cases report
    Chen Xue, Li Yuangao.
    West China Journal of Stomatology. 2022, 40(4):  483-488.  doi:10.7518/hxkq.2022.04.017
    Abstract ( 65 )   HTML ( 10 )   PDF(pc) (2146KB) ( 40 )   Save
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    Congenital dental deficiency can lead to aesthetic and masticatory dysfunction, which have a great effect on the quality of life of patients. Genetic inheritance is the determining factor of congenital dental deficiency, which may follow the pattern of autosomal dominant, recessive, or sex chromosome inheritance. However, the specific genetic mechanisms are not clear. The prevalence of congenital absence of permanent teeth in the general population worldwide are not high, and familial oligodontia in clinically healthy patients is rare. This paper reported two cases of familial non-syndromic congenital teeth loss and included a review of literature referring to the etiology, clinical manifestations, and treatment of congenital dental deficiency.

    Conservative management with factorreplacement alone for hemophilic pseudotumor in the mandible: a case report
    Wu Juan, Su Jimei, Ye Xiaowei, Xu Weiqun
    West China Journal of Stomatology. 2022, 40(4):  489-493.  doi:10.7518/hxkq.2022.04.018
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    Hemophilic pseudotumor is a rare but serious complication that occurs less frequently in the jaw, and it may lead to bleed uncontrollably and even death. This paper reported a case of hemophilic pseudotumor with extensive osteo-destruction in the right mandible, treated by factor Ⅷ replacement and with no recurrence after 10 years of follow-up.

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