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Consensus on the preparation margin and restoration margin in ceramic esthetic rehabilitation
Yu Haiyang, Yue Li, Liu Weicai, Liu Feng, Niu Lina, Shao Longquan, Liao Hongbing, Luo Xiaoping, Li Hongbo, Jiang Qingsong, Yu Hao, Zhao Bin, Wu Zhe, Li Changyi, Wu Guofeng, Wang Yan, Mou Yandong, Liu Yunsong, Zhang Haiyang, Chen Jihua, Liu Hongchen
West China Journal of Stomatology    2022, 40 (2): 123-133.   DOI: 10.7518/hxkq.2022.02.001
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In esthetic rehabilitation, methods used to enhance the margin quality have always been the focus and difficulty of improving the level of diagnosis and treatment, prevention and treatment of complications, and collaboration between clinicians and technicians. However, it is impeded by the ambiguous definition and classification of margin, unstandardized tooth preparation, manufacturing process of restoration, and lack of reliable means of checking the quantitative requirements of preparation or restoration. The digital technologies that are increasingly applied, such as intra-oral scanner, impression scanner, and computerized numerical control cutting machine, have strict requirements about margin quality. Failure of recognizing margins by these scanners will hinder the digital process of diagnosis and treatment. Even if these sharp and narrow margins are successfully scanned, they cannot be milled accurately. To overcome these problems, this article demonstrated the clear and complete definition of preparation margin and restoration margin, as well as their subclassifications, by analyzing the target restoration space from a geometric perspective. Practical approaches to measuring the margin width and inspecting the margin quality were proposed. The new and full understanding and proposal about preparation margin and restoration margin characterized by measurements will effectively support the thoroughly digitalized process of esthetic rehabilitation using porcelain in fixed prosthodontics, which is based on the guidance of values.

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China experts' consensus on preventive and interceptive orthodontic treatments of malocclusions of children
Li Xiaobing, Ye Quanfu, He Hong, Lu Haiping, Zhu Min, Jiang Ruoping, Zou Shujuan, Han Xianglong, Zhou Li, Chen Ke, Yuan Xiao, Zhang Junmei, Tan Lijun, Yin Chang, He Zhou, Li Ang, Cheng Bin, Ruan Wenhua, Huang Fang, Liu Juan, Ma Lan, Zou Rui, Yang Fang, Zhang Weibing, Tian Yulou, Jiang Beizhan, Shao Linqin, Huang Yang, Tang Liqin, Gao Li, Zhou Chenchen
West China Journal of Stomatology    2021, 39 (4): 369-376.   DOI: 10.7518/hxkq.2021.04.001
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Malocclusion is one of the three most common oral diseases reported by World Health Organization(WHO). In China, its incidence rate is rising. Malocclusion seriously affects the dental and maxillofacial function, facial appearance and growth development of nearly 260 million children in China, and what is more, it affects their physical and mental health development. Malocclusion occurrence is related to genetic and environmental factors. Early treatment of malocclusion can create a good dental and maxillofacial development environment, correct abnormal growth and control the adverse effects of abnormal genetic factors. It can effectively reduce the prevalence of children's malocclusion and enhance their physical and mental health. This is an urgent need from the economic perspective of our society, so it has great practical and social significance. Experts from the project group “standard diagnose and treatment protocols for early orthodontic intervention of malocclusions of children” which initiated by China National Health Institute of Hospital Administration wrote the “China Experts' Consensus on Preventive and Interceptive Orthodontic Treatments of Malocclusions of Children”, which aims to guide and popularize the clinical practice, improve the clinical theory and practice level, and accelerate the disciplinary development of early treatment of children's malocclusion in China. The consensus elaborates the harmfulness of malocclusion and the necessity of early treatment, and brings up the principles and fundamental contents. Based on the law of dental and maxillofacial development, this paper puts forward the guiding suggestions of preventive and interceptive treatments in different stages of dental development ranging from fetus to early permanent dentition. It is a systematic project to promote and standardize the early treatment of malocclusion. Through scientific and comprehensive stratified clinical practice and professional training, the clinical system of early treatment of malocclusion in China will eventually be perfected, so as to comprehensively care for children's dental and maxillofacial health, and improve their oral and physical health in China.

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Distal-triangular flap design for impacted mandibular third molars: a randomized controlled trial
Liu Jiyuan, Liu Chang, Pan Jian, Qu Tao, Hua Chengge.
West China Journal of Stomatology    2021, 39 (5): 598-604.   DOI: 10.7518/hxkq.2021.05.016
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Objective

This prospective study was performed to evaluate whether the distal-triangular flap was a practical alternative surgical approach for extracting mandibular third molars.

Methods

Sixty participants with impacted mandibular third molars were randomly divided into three groups: group A, distal-triangular flap; group B, Szmyd flap; and group C, envelope flap. The impacted third molars were extracted by the corresponding flapping method. During a three-month follow-up observation after the extraction, the postoperative pain, swelling, mouth opening, and periodontal status were recorded and analyzed by ANOVA and chi-square tests.

Results

The 60 participants had successful extraction and 3-month follow-up observation. No participant suffered from postoperative infections, lower lip disorder, or tongue sensory disorders. No statistical differences were found in the postoperative symptoms and signs of the three flap designs, such as postoperative pain, swelling, mouth opening, and periodontal status (P>0.05).

Conclusion

The distal-triangular flap was as safe and reliable as the Szmyd and envelope flaps but more advantageous because of its convenient operative field exposure and low requirement for the patient's mouth opening. Thus, the distal-triangular flap is one of the alternative flap options for extracting impacted mandibular third molars.

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Experts’ consensus on perioperative management of tooth extractions in patients receiving oral antithrombotic treatment
Pan Jian, Xue Yang, Zhao Jihong, Zhou Qing, Zou Duohong, Chen Songling, Han Bing, Cui Nianhui, Liu Xian, Wang Liao, Hu Kaijin
West China Journal of Stomatology    2022, 40 (3): 255-263.   DOI: 10.7518/hxkq.2022.03.002
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Thromboembolic diseases, which comprise venous thromboembolic diseases and arterial thromboembolic diseases, have become the number one cause of death worldwide. To prevent or treat thrombosis, patients with thromboembolic diseases need to take antithrombotic drugs, which would increase the risk of bleeding during and after surgery. Tooth extraction is the most common operation in oral and maxillofacial surgery clinics. Although patients given oral antithrombotic drugs do not need to undergo drug withdrawal, the perioperative management of such patients remains confusing to most clinicians. Moreover, the potential risk factors for bleeding warrant further study. To improve the clinicians’ knowledge of perioperative management for patients subjected to tooth extractions with oral antithrombotic drugs, experts have drafted this consensus focusing on preoperative bleeding risk assessment, intraoperative operating norms, and postoperative care to summarize the points needing attention.

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Clinical analysis on the root fracture of the maxillary first molar
Yuan Zhiyao, Zou Xihong, Dai Linlin, Ao Huizhi, Li Houxuan.
West China Journal of Stomatology    2021, 39 (5): 555-559.   DOI: 10.7518/hxkq.2021.05.009
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Objective

This study aimed to investigate the common types and directions of root fractures of the maxillary first molar and the influence of root canal treatment on the prevalent sites of root fractures.

Methods

A total of 274 maxillary first molars with root fractures diagnosed via cone beam computed tomography were included. The root fractures of nonendodontically and endodontically treated teeth were identified to be spontaneous and secondary root fractures, respectively. The sites, types, and directions of spontaneous and secondary root fractures were determined.

Results

Among the spontaneous root fractures, the proportion of palatal root fractures (56.1%) was higher than those of mesial buccal root fractures (36.1%) and distal buccal root fractures (7.8%). Among the secondary root fractures, the proportion of mesial buccal root fractures (52.7%) was higher than those of palatal root fractures (36.5%) and distal buccal root fractures (10.8%). The distribution of predominant fracture sites was statistically significant (P<0.05), and vertical root fracture was the most common type. Palatal and buccal roots were commonly fractured at the mesiodistal and buccal-palatal directions, respectively.

Conclusion

This study provided an epidemiological basis for the clinical features of root fractures of the maxillary first molar. During the dia-gnosis and treatment of the maxillary first molar, the possibility of palatal root fractures should be considered. The occurrence of mesial buccal root fractures may be related to root canal treatment. Therefore, the risk of mesial buccal root fractures caused by iatrogenic factors should be minimized.

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Experts’ consensus on space management of mixed dentition
Guo Weihua, Wang Jun, Chen Xu, Wang Xiaojing, Zhao Wei, Song Guangtai, Wu Li’an, Jiang Beizhan, Zhang Qiong, Wang Jun, Li Yu, Zhao Ning, Tan Jiali, Li Huang, Shu Rui, Zhou Chenchen, Fu Lei, Chen Xuepeng, Zou Jing
West China Journal of Stomatology    2022, 40 (3): 264-270.   DOI: 10.7518/hxkq.2022.03.003
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The mixed dentition stage is the period between primary and permanent dentition. The following biological processes are complicated and variable: jaw growth, development of inherited permanent teeth embryo, physiological absorption of primary teeth, restoration of surrounding alveolar bones, and growth and function establishment of soft tissues. For the normal development of the jaw, the establishment of the good occlusion relationship, development, and function of soft tissue is very important, whether or not the primary teeth are normally replaced by the permanent teeth in the mixed dentition stage. The eruption space is linked to the normal replacement of primary and permanent teeth. The presence of a mixed dentition space results in the incidence and progression of malocclusion and impacts the normal growth and development of the occlusion, jaw, and face. Space management in the mixed dentition stage is a crucial means to prevent and reduce malocclusion. The following were discussed and analyzed: the possible space problems, why the size of the space was affected, the content that needs to be assessed, and the methods of space management in the mixed dentition that can be used to unify and standardize the management of mixed dentition. This paper was developed to serve as a guide for regulated space management during the mixed dentition period.

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Progress and perspectives on cell-free regenerative endodontic therapy
Zhou Jian, Su Yingying, Wang Song-ling
West China Journal of Stomatology    2022, 40 (1): 1-6.   DOI: 10.7518/hxkq.2022.01.001
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Although teeth with pulpitis/apical periodontitis are saved after successful endodontic therapy, they are devitalized and susceptible to reinfections and fractures. The development of biology-based approaches for dental pulp regeneration or repair is possible today because of recent advances in tissue engineering and biomaterials. Cell-free regenerative endodontic therapy offers a promising strategy for the treatment of necrotic immature permanent teeth in children and adolescents. However, studies are underway to determine whether this procedure can be applied to mature teeth.

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Vessel anastomosis in free flap reconstruction for oral and maxillofacial defects: techniques and key points
Li Chunjie, Han Bo, Zhu Guiquan.
West China Journal of Stomatology    2022, 40 (3): 271-278.   DOI: 10.7518/hxkq.2022.03.004
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The quality of vessel anastomosis is a key element for the success of free flap reconstruction. When adopting free flaps for oral and maxillofacial defect reconstruction, skills in selecting vessels, determining the clinical manifestations of the recipient vessel, and anastomosis technique are needed. Key points on postoperative flap observation were also required. We are experienced on this subject given that we have accomplished more than 1 000 free flaps for patients with oral and maxillofacial defects in the last 5 years. In this article, we summarize the skills and key points in free flap reconstruction of oral and maxillofacial defects, including vessel anastomosis skills, vessel selection, and vessel crisis diagnosis.

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A retrospective study of endodontic microsurgery about 302 patients
Chen Yiyan, Pradan Siras Prasad, Yang Jinbo
West China Journal of Stomatology    2021, 39 (4): 458-463.   DOI: 10.7518/hxkq.2021.04.013
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Objective

To investigate the outcome of endodontic microsurgery and analyze the potential prognostic factors, and to evaluate the value of surgical classification by Kim and Kratchman.

Methods

Collecting clinical examination and radiographical examination of endodontic microsurgery cases (which were followed up at least 1 year), which were classified according to Kim and Kratchman, and we analyzed the outcome of endodontic microsurgery and its potential prognostic factors.

Results

302 patients (400 teeth) who received endodontic microsurgery were included. The one year success rate of endodontic microsurgery was 94.25%. Different classification had significant influences on the outcome of endodontic microsurgery (P<0.05), and the success rate of class B and C were better than those of class D, E, and F. The position of teeth had significant influences on the outcome of endodontic microsurgery (P<0.05). The success rate of maxillary teeth was higher than that of mandibular teeth. The success rate of anterior teeth was higher than that of posterior teeth (P<0.05). The quality of root end filling and first or second surgery had no effect on the outcome (P>0.05).

Conclusion

Endodontic microsurgery is an effective treatment method for saving affected teeth, and it can get a good result. Tooth position and classification are the potential prognostic factors. The surgical classification of Kim and Kratchman can help to predict the outcome of endodontic microsurgery.

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Retrospective study on the merits of bone grafts and the influence of implant protrusion length after osteotome sinus elevation surgery
Yang Dawei, Xiao Jingyi, Zhang Peng, Lu Boyao, Liang Xing.
West China Journal of Stomatology    2021, 39 (5): 570-575.   DOI: 10.7518/hxkq.2021.05.012
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Objective

This study aims to evaluate the endo-sinus bone remodeling of dental implants placed via osteotome sinus floor elevation (OSFE) after 6 months and using different implant protrusion lengths and bone grafts through cone beam computed tomography (CBCT).

Methods

Ninety-six patients with 124 implants were included and assigned into four groups. Group 1: implant protrusion length<4 mm with bone graft; group 2: implant protrusion length>4 mm with bone graft; group 3: implant protrusion length<4 mm without bone graft; group 4: implant protrusion length>4 mm without bone graft. Apical bone gain (ABG), cortical bone gain (CBG), bone density gain (BDG), and marginal bone loss (MBL) were observed and analyzed at baseline and 6 months after implant surgery.

Results

The CBG in grafted groups 1 and 2 was higher than that in non-grafted groups. The ABG and BDG were higher in non-grafted groups 3 and 4 than in grafted groups, and the levels in group 3 were higher than those in group 4. The CBG in grafted group 2 was higher than that in group 1. No significant difference was observed in MBL analysis.

Conclusion

The BDG of IPL<4 mm implants was higher than IPL>4 mm implant when bone grafts were not applied. No relevance was observed between IPL and CBG. Bone grafts can accelerate endo-sinus bone remodeling by increasing CBG and dissipating the influence of IPL on BDG.

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Minimally invasive treatment of calcified root canals in anterior teeth with digital guide technique
Gao Yuxuan, Wang Liu, Fu Yujie, Yang Fan, Zhang Lan, Huang Dingming
West China Journal of Stomatology    2022, 40 (1): 111-122.   DOI: 10.7518/hxkq.2022.01.017
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Objective

This study aims to establish a minimally invasive treatment using a customized digital template and a miniaturized bur for pulp canal obliteration (PCO).

Methods

Cone-beam computed tomography (CBCT) and digital oral scans of patients diagnosed with PCO in anterior teeth were obtained. Root canal morphology was reconstructed to accurately show the location, length, and direction of obliteration. A digital template was designed and fabricated using visual design software and 3D printing technology and used as guide for the miniaturized bur and drill sleeve during calcified tissue removal. A conventional root canal treatment was performed after the lumen of the root canal was reached.

Results

In both cases, the planned access cavity and glide paths were successfully established. In case 1, the deviated angle of the access cavity was 1.37°±0.07°, the deviation at the bottom of the miniaturized bur was 0.08-0.81 mm, the deviation at the tip of the bur was 0.05-1.13 mm, and difference in substance loss was 0.84-4.25 mm³. In case 2, the deviated angle of the access cavity was 3.09° ± 0.12°, the deviation at the bottom of the bur was 0.09-0.68 mm, the deviation at the tip of the bur was 0.29-0.66 mm, and the difference in substance loss was 0.55-3.79 mm3.

Conclusion

Micro-guided endodontics is a novel approach for localizing and negotiating obliterated root canals and guarantees long-term prognosis without requiring excessive hard tissue removal.

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Investigation on the quality analysis of 1 312 single crown digital models
Lu Jiayi, Zhao Junyi, Gao Jing, Yu Haiyang.
West China Journal of Stomatology    2022, 40 (1): 52-60.   DOI: 10.7518/hxkq.2022.01.008
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Objective

This study aimed to investigate the quality of single crown digital models, enhance communication between clinicians and technicians, and improve the quality of restorations to further reduce remake rate.

Methods

A total of 1 312 single crown digital models (180 anterior teeth, 294 premolars, and 838 molars) were randomly selected from a large commercial dental factory. The digital models were evaluated by three investigators with the same working experience with the same intraoral scanning system (CEREC). CEREC SW 4.4 was used in capturing the images of single crown preparations, and prepCheck 3.1 was used in evaluating the quality of single crown digital models.

Results

Approximately 6.55%, 0.08%, 81.17%, 19.59%, and 22.48% of 1 312 single crown digital models did not meet the standards of the undercut, surface quality, margin quality, buccal-lingual taper, and mesiodistal taper, respectively. Moreover, 23.25%, 28.51%, 28.43%, and 28.35% of the investigated single crown digital models did not meet the standards of the buccal inclination taper, lingual inclination taper, mesial inclination taper, and distal inclination taper, respectively. The quality of anterior teeth, premolars, molars at the margin quality, buccal-lingual taper, mesiodistal taper, buccal inclination taper, lingual inclination taper, mesial inclination taper, and distal inclination taper significantly varied in the evaluation results (P<0.01).

Conclusion

In addition to the undercut and surface quality met the standard, the overall situation of the quality of the single crown digital preparation model was poor, and the quality of the preparation needs to be improved urgently.

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The investigation of energy metabolism in osteoblasts and osteoclasts
Shi Yu.
West China Journal of Stomatology    2021, 39 (5): 501-509.   DOI: 10.7518/hxkq.2021.05.002
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The maintenance of bone homeostasis is critical for bone health. It is vulnerable to cause bone loss, even severely osteoporosis when the balance between bone formation and absorption is interrupted. Growing evidence has shown that energy metabolism disorders, such as abnormal glucose metabolism, irregular amino acid metabolism, and aberrant lipid metabolism, can damage bone homeostasis, causing or exacerbating bone mass loss and osteoporosis-related fractures. Here, we summarize the studies of energy metabolism in osteoblasts and osteoclasts and provide a better appreciation of how energy metabolism, especially glucose metabolism maintains bone homeostasis. With this knowledge, new avenues will be unraveled to understand and cue bone-related diseases such as osteoporosis.

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Clinical study of periodontal endoscope-assisted subgingival scaling in the treatment of residual pocket
Xu Yujuan, Zhao Lei, Wu Yafei, Duan Dingyu
West China Journal of Stomatology    2021, 39 (4): 441-446.   DOI: 10.7518/hxkq.2021.04.010
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Objective

To compare the treatment effects of periodontal endoscope-assisted and traditional subgingival scaling on residual pockets.

Methods

A total of 13 patients with periodontitis from Dept. of Periodontics, West China Hospital of Stomatology, Sichuan University were recruited. After 4-6 weeks of initial treatment, the residual pockets with a probing depth (PD) of ≥4 mm and attachment loss (AL) of ≥4 mm and bleeding on probing were examined with traditional (control group) and periodontal endoscope-assisted subgingival scaling (endoscopy group) in a randomly controlled split-mouth design. At baseline and 6 weeks and 3 months after treatment, plaque index (PLI), PD, AL, and bleeding index (BI) were measured. Differences in these clinical parameters within and between groups and patient-reported outcomes were compared.

Results

A total of the 694 sites of 251 teeth were included in this trial. Both groups showed significant improvement in each periodontal parameters 6 weeks and 3 months after treatment (P<0.001). For sites in a single-rooted tooth, sites with PD≥5 mm, and sites without vertical alveolar bone resorption and furcation involvement, the PD in endoscopy group was significantly lower than that in the control group at 6 weeks and 3 months after treatment (P<0.05).

Conclusion

Periodontal endoscope-assisted subgingival scaling resulted in better effects than traditional subgingival scaling when the residual pockets were in a single-rooted tooth, with a PD of ≥5 mm but without vertical alveolar bone resorption and furcation involvement.

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Effect of the thicknesses of bulk-fill composites on bonding strength
Wang Ying, Yang Jiaxue, Xie Haifeng, Chen Chen
West China Journal of Stomatology    2022, 40 (2): 169-174.   DOI: 10.7518/hxkq.2022.02.007
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Objective

This work evaluated the effects of thickness on resin bonding strength.

Methods

We set the two bulk-fill composites Filtek Bulk Fill Posterior (FBF) and Tetric N-Ceram Bulk Fill (TBF) as the experimental groups and the two conventional composites Filtek Z100 (Z100) and Spectrum TPH (ST) as the control groups. The translucency parameter (TP), color difference, Vickers hardness (HV), and microtensile bond strength (μTBS) of dentine and the resin composites were measured at different depths.

Results

In each group, TP and HV decreased with the increase in thickness. At the same depth, the TP of the bulk-fill composites was higher than that of the conventional composites. At the same depth, the HV of the four different resin composites followed the order of Z100>FBF>TBF>ST (except for the upper surface). Except for FBF at 3 and 4 mm, all of the other groups showed no visible color change at all the tested thicknesses. Although the μTBS values of the four different composites obtained through the bulk-fill technique were lower than those of composites obtained through the incremental fill technique, the μTBS of the bulk-fill composites obtained through the bulk-filling technique can reach 30 MPa.

Conclusion

Bulk-fill composites applied in single 4 mm increments can meet the requirements of clinical application. However, the color stability of some bulk-fill composites cannot be maintained.

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Evaluation of therapeutic effect and health economics of general anesthesia and routine outpatient dental treatment in children with severe early child caries
Liu Yaqi, Zhang Qiong, Wang Yan, Qu Xing, Zou Jing
West China Journal of Stomatology    2021, 39 (6): 703-708.   DOI: 10.7518/hxkq.2021.06.012
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Objective

To evaluate the efficacy and health economics of the comprehensive therapy for the children with severe early child caries (S-ECC) under dental general anesthesia (DGA) and conventional outpatient treatment to provide references for dentists and parents in the choice of clinical treatment.

Methods

A retrospective cohort study was conducted on S-ECC children aged 36-71 months and who received dental treatment under general anesthesia or routine outpatient situation. The filled tooth survival rate, treatment cost, and cost-filled tooth survival time of the two groups were compared, and the curative effect and health economics was evaluated.

Results

The filled tooth survival rate of the DGA group was higher than that of the routine outpatient group (P<0.05). The average direct medical cost per filled tooth was significantly higher in the DGA group than in the routine outpatient group (P<0.05). The direct medical cost-filled tooth survival time ratio in the DGA group was higher than that in the routine outpatient group (P<0.05), but no significant difference was observed in the total medical cost-filled tooth survival time ratio (P>0.05).

Conclusion

Compared with the conventional outpatient treatment group, the treatment outcomes of S-ECC under general anesthesia were better, and the costs were higher. However, no significant difference was observed in the total medical cost-filled tooth survival time between these two groups, and the conventional outpatient treatment did not have evident economic advantages.

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Finite element analysis of the effects of periodontal tissue temperature by continuous wave technique
Zhang Jianguo, Liu Jun, Cen Rong, Hu Fengling
West China Journal of Stomatology    2021, 39 (4): 447-452.   DOI: 10.7518/hxkq.2021.04.011
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Objective

The safety of root canal filling with 200 °C hot gutta-percha was investigated to study the effect of continuous wave technique combined with high-temperature injectable gutta-percha condensation technique on the surface temperature of periodontal tissue.

Methods

CT technique and Mimics, Geomagic, and Solidworks software were utilized to build the entity models of alveolar bone, dentin and root canal, periodontal ligament, and blood flow, respectively, which were then assembled in Solidworks into a finite element model of tooth with blood flow. By utilizing ABAQUS collaborative simulation platform, fluid-structure coupling was analyzed on the whole process of root canal filling. Consequently, the surface temperature of the periodontal tissue was obtained.

Results

In the absence of blood flow, the temperature of the periodontal ligament surface reached 50.048 ℃ during root canal filling with 200 ℃ gutta-percha. Considering blood flow, the temperature of periodontal ligament surface was 39.570 ℃.

Conclusion

The temperature of the periodontal ligament surface increased when the continuous wave root canal was filled with 200 ℃ gutta-percha, and the periodontal tissue was not damaged.

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Experts’ consensus on precaution and treatment for complications of sagittal split ramus osteotomy
Zhu Songsong, Wang Xudong, Yang Xuewen, Wang Xiaoxia, Tian Lei, Liu Shuguang, Zheng Guangsen, Tang Zhenglong, Wu Guomin, Li Zhiyong, Bai Xiaofeng, Huang Xuanping, Huang Li, Xi Weihong, Zhu Yaomin
West China Journal of Stomatology    2022, 40 (3): 247-254.   DOI: 10.7518/hxkq.2022.03.001
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Sagittal split ramus osteotomy (SSRO) is a versatile orthognathic procedure for correcting mandibular deformities. Various complications can possibly occur when performing SSRO, and it can even cause serious adverse consequences because of the complexity of anatomy and operative procedures. The types of complications and their accompanying clinical manifestations are closely related to the choice of diagnosis and treatment strategies and clinical outcomes. To discuss the causes, prevention, and treatment measures of various common complications of SSRO, domestic orthognathic surgery experts prepared this consensus to increase the awareness of SSRO complications, thereby ensuring safe surgical procedure and good results.

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Expanding the concept of patient-derived xenografts cohorts in head and neck cancer: current and future perspectives
Zhang Zhiyuan, Sun Shuyang
West China Journal of Stomatology    2021, 39 (6): 617-623.   DOI: 10.7518/hxkq.2021.06.001
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Head and neck cancer is the seventh common cancer in the world, and various existing treatment strategies provide modest benefit for most patients with head and neck cancer. Meanwhile, therapeutic strategies lacking molecular typing significantly hinder the development of individualized treatment for head and neck cancer. In recent years, connected by preclinical models, the novel ideal has gradually reached a consensus in terms of facilitating inter-transformation of clinical problems and basic achievements. As a bridge between basic research and clinical transformation, patient-derived xenografts (PDX) models precisely replicate genetic characteristics and tumor evolution, which are displaying great vitality in elucidating the mechanism of tumorigenesis and progression. Moreover, cohorts composed of several PDX models highlight the unique advantages of mice for drug screening and biomarker analysis for patients. This ideal preclinical model explores potential treatment strategies suited the ethical standards as much as possible for patients.

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The question about the numerical value and quantitative data transfer of implant prosthodontics—orom experience guidance to digital guidance
Yu Haiyang
West China Journal of Stomatology    2021, 39 (4): 386-397.   DOI: 10.7518/hxkq.2021.04.003
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The correct implant site design and placement are the basic clinical techniques that must be known for implant restoration. For a long time, most implants have been placed by free hands, and the choice of site is mostly dependent on the accumulation of long-term experience of the surgeon. The selection of implant site guided by this experience analogy logic is often based on the surgeon's level of experience,which often makes it very easy to produce complications related to the implant restoration of the incorrect site. In contrast, a clinical program using digital guidance and real-time measurable verification has emerged based on the restoration-oriented implantation concept, which marks the formation of an accurate, measurable and verifiable whole-process digital implant prototype. Furthermore, from the perspective of surveying, the numerical requirements that digital implant restoration relies on are actually incomplete to the four elements of measurement, which leading to the doubts about its authenticity. This article will question the numbers in implant restoration, and conduct a preliminary demonstration, and propose a new reliable actual measurement and verification method of the correct location and the numerical requirements of the restoration space and a new clinical program that relies on numbers from the perspective of the evolution of digital restoration, guided implantology and actual measurement technology. And this article further discusses the current mainstream implant restoration technology based on experience analogy which cannot effectively support the whole process of digital implant restoration and provides a new logical cognitive basis for the final realization of the entire process of digital implant restoration.

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Abnormal static and dynamic brain function in patients with temporomandibular disorders: a resting-state functional magnetic resonance imaging study
Yin Yuanyuan, Li Fei, He Shushu, Chen Song
West China Journal of Stomatology    2021, 39 (6): 682-689.   DOI: 10.7518/hxkq.2021.06.009
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Objective

This study was conducted to investigate the brain function of patients with temporomandibular disorders (TMD) by combining the static and dynamic amplitudes of low-frequency fluctuation (ALFF).

Methods

Thirty patients with TMD and 20 healthy controls were enrolled. All the participants completed their questionnaires, received clinical examinations, and underwent resting-state functional magnetic resonance imaging scanning. We compared the static and dynamic ALFF between the patients and healthy controls by conducting a two-sample t-test with AlphaSim correction for multiple comparisons. The correlation between the static and dynamic ALFF of the brain regions with significant group differences and clinical measurements was analyzed.

Results

The patients with TMD showed increased static and dynamic ALFF in the posterior cingulate cortex compared with that of the controls (whole-brain level, uncorrected P=0.005; region of interest level with AlphaSim correction, voxel level P<0.005, cluster level P<0.05). The dynamic ALFF of the posterior cingulate cortex was negatively correlated with bilateral condylar vertical discrepancies. The dynamic ALFF in the medial orbitofrontal cortex of the patients with TMD was greater than that of the controls (whole-brain level AlphaSim correction, voxel level P<0.005, cluster level P<0.05).

Conclusion

Our findings revealed that the resting-state brain function of the posterior cingulate cortex and the medial orbitofrontal cortex of patient with TMD increased. These changes probably indicated the potential central mechanisms underlying the increased self-relevant thoughts, negative emotion, and abnormal emotion regulation in TMD.

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Research progress on the application of framework nucleic acid in bone regeneration
Lin Yunfeng
West China Journal of Stomatology    2021, 39 (6): 624-632.   DOI: 10.7518/hxkq.2021.06.002
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Framework nucleic acid (FNA) is a set of DNA nanostructures characterized by the framework morphology. It can design rational DNA sequences and follow the principle of complementary base pairing to construct FNA. The recent discovery of FNA constructed by DNA nanotechnology has great application potential in the field of bone regene-ration. It plays a positive role in the osteogenic differentiation of stem cells, bone regeneration, vascular regeneration, neuromodulation, immune regulation, and drug delivery. Here, we reviewed the current study findings on FNA in the field of bone regeneration.

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Study on the application of oral digital design in aesthetic restoration of anterior teeth of cleft lip/palate patients
Yao Jinfeng, Deng Mengzhao, Xie Tian, Chen Kan, Wang Qiuxu, Liang Zhigang.
West China Journal of Stomatology    2021, 39 (5): 582-590.   DOI: 10.7518/hxkq.2021.05.014
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Objective

A study was conducted to investigate the clinical effects of oral digital design on the aesthetic restoration of anterior teeth of cleft lip/palate patients.

Methods

Nine adult cleft lip/palate patients who need aesthetic restoration of anterior teeth were recruited. Digital information of patients' dental arches, the surrounding soft tissue and face were captured by digital camera and scanner. The aesthetic analysis and design were conducted using keynote and 3shape software and were demonstrated to the patients. The optimized treatment plan was ensured by communicating with the patients. Digital wax-up models were exported and printed into resin diagnostic models, which were then utilized in the treatment process to guide the doctors and the technicians in tooth preparation and in making the final restorations, respectively. The adhesive procedure was completed after satisfactory try-in. Aesthetics assessment was conducted in accordance with the anterior esthetic evaluation form. The scores of patient's satisfaction were recorded on a questionnaire containing six items of aesthetic index and doctor-patient communication. Patients were interviewed and examined after 1, 3, 6, and 12 months, respectively, and the clinical effects of restorations were evaluated.

Results

All nine patients had satisfactory clinical results. The aesthetic defects of the patients were effectively addressed. All treatments met the requirements of the preoperative digital designs. The patients' scores were all above 90 on the satisfaction scale. At 12 months after the operation, the clinical effects of restorations of all cases achieved A class in each evaluation indicator.

Conclusion

For cleft lip/palate patients with esthetic defect in the anterior teeth, the digital design plays an important role in optimizing the treatment plan and guides the whole treatment process. This design can help clinicians achieve predictable satisfactory aesthetic results.

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Clinical retrospective study on the digital data of orthodontic cases by Andrews six elements
Liu Chaofeng, Xu Yanhua, Yi Chunyan, Liu Yan
West China Journal of Stomatology    2022, 40 (2): 183-188.   DOI: 10.7518/hxkq.2022.02.009
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Objective

Andrews six elements was used to explore the possible influences of gender, extraction/non-extraction, and different bracket types on the evaluation of orthodontic treatment outcome.

Methods

Digital data from 320 selected orthodontic cases in Kunming Medical University Affiliated Stomatological Hospital during the period of 2016—2020 were divided into groups in accordance with gender, tooth extraction, and type of orthodontic brackets (DamonQ self-ligating brackets and MBT brackets). Measurement was performed using Andrews six elements as standard. The mean and standard deviation of each individual score and total score for different groups were calculated and statistically tested.

Results

The differences in total scores between female and male cases exhibited no statistical significance (P>0.05). By contrast, the scores in skeletal width change of the maxilla between extraction cases and non-extraction cases presented statistical significance (P<0.05). Moreover, the scores in the anteroposterior change in the position of the maxillary incisors, the bucco-lingual border change of the mandibular arch, and the skeletal width change of the maxilla between the DamonQ self-ligating bracket and MBT bracket cases presented statistical significance (P<0.05). The cases with DamonQ self-ligating brackets had significantly lower scores than the cases with MBT brackets in the bucco-lingual border change of the mandibular arch, the skeletal width change of the maxilla, and the anteroposterior change in position of the maxillary incisors.

Conclusion

Digital 3D models can be used in the clinical retrospective studies of patients after orthodontic treatment. These models can be measured repeatedly and have clinical application value. For cases with incomplete orthodontic treatment, the control of the anteroposterior position of the incisor and the width of the arch of the upper tooth is crucial. Total treatment efficiency between female and male cases exhibited no difference, but the skeletal width change of the maxilla between extraction and non-extraction cases may exert an effect on cases with complete orthodontic treatment. The group that used DamonQ self-ligating brackets may achieve good adjustment of the bucco-lingual border change of the arch.

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Evaluation of hyperbaric oxygen therapy for the osteoradionecrosis of the jaws: Meta-analysis
Yin Yin, Zeng Wei, Jing Wei, Tang Wei, Guo Weihua
West China Journal of Stomatology    2021, 39 (6): 690-697.   DOI: 10.7518/hxkq.2021.06.010
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Objective

This study was performed to investigate the effects of hyperbaric oxygen and other approaches for treating the osteoradionecrosis of the jaws (ORNJ) systematically.

Methods

According to the preset inclusion and exclusion criteria, randomized controlled trials and cohort studies on hyperbaric oxygen in the treatment of ORNJ were screened, and foreign language databases such as PubMed, EMBASE, and Cochrane library were searched via a computer; Chinese databases such as CNKI, VIP, Wanfang data, and CBM were searched from the established database to September 2020. Relevant books were searched manually to collect all literatures on the efficacy of hyperbaric oxygen and its related therapies in ORNJ treatment. Two researchers were independent and mutually blind, the papers were selected, data were collected, and the bias risk was evaluated. If any difference was detected, it would be decided by discussion or arbitrated by a third party. The data related to the efficacy of hyperbaric oxygen and its related therapy in the treatment of the ORNJ were extracted, and the Revman5.4 software was used for Meta-analysis. In case of large heterogeneity, sensitivity analysis was performed. A funnel chart was used to evaluate possible publication bias qualitatively.

Results

Four randomized controlled trials and seven cohort studies were included in Meta-analyses. In ORNJ treatment, no significant differences between the group subjected to hyperbaric oxygen and both surgery and antibiotics and the group that underwent both surgery and antibiotics (RR=1.16, 95%CI: 0.86~1.58, P>0.05); between the group with hyperbaric oxygen and the group with antibiotics (RR=0.83, 95%CI: 0.63~1.09, P>0.05); between the group with hyperbaric oxygen and the group with antifibrotic drugs (RR=0.07, 95%CI: 0.00~155.86, P>0.05); between the group with single or combined use of HBO and the group with other intervention methods (RR=0.89, 95%CI: 0.67~1.19, P>0.05).

Conclusion

Hyperbaric oxygen therapy cannot replace surgery and antibiotic therapy. Hyperbaric oxygen therapy is not superior to antibiotics and antifibrotic drugs, but the benefits of antifibrotic drugs should be further explored.

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Tilted implantation technique for edentulous patients
Fan Zhen, Liu Yue, Wang Zuolin
West China Journal of Stomatology    2021, 39 (4): 377-385.   DOI: 10.7518/hxkq.2021.04.002
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The tilted implantation technique is characterized by placing the implant at an angle of more than 15° and less than 45° from the horizontal plane. This technique can avoid damaging the maxillary sinus, inferior alveolar nerve, nasal base, and other anatomical structures when the height of the upper and lower jaw available bone is insufficient, to maximize the use of available bone and avoid a large range of bone increment. The tilted implantation technique can reduce the trauma of the surgery, increase the possibility of immediate restoration and shorten the treatment cycle, which has been widely used clinically. In this review, the scope of application, design elements, design scheme and complications of the tilted implantation technique for edentulous patients will be described.

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An investigation of the microstructure and mechanical properties of dental zirconia manufactured by digital light processing 3D printing
Mei Ziyu, Lu Yuqing, Lou Yuxin, Zhang Junjing, Sun Manlin, Yu Haiyang.
West China Journal of Stomatology    2021, 39 (5): 576-581.   DOI: 10.7518/hxkq.2021.05.013
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Objective

This study was performed to investigate the microstructure and mechanical properties of dental zirconia manufactured by digital light processing (DLP) 3D printing and the clinical application prospects of this material.

Methods

The experiment (DLP) group was zirconia manufactured by DLP 3D printing, and the control (MILL) group was milled zirconia. The density, grain size, and phase composition were measured to study the microstructure. Flexural strength was measured by using three-point bending tests, while Vickers hardness was determined through a Vickers hardness tester. Fracture toughness was tested using the single-edge V-notched beam method.

Results

Zirconia density of the DLP group was (6.019 8±0.021 3) g·cm-3, and the average grain size was (0.603 0±0.032 6) μm, but without statistical difference with the corresponding values of the MILL group (P>0.05). Tetragonal phase was found in the X-ray diffraction patterns of the DLP and MILL groups. The flexural strength of the DLP group was (1 012.7±125.5) MPa, and Vickers hardness was (1 238.5±10.8) HV1, which was slightly lower than that of the MILL group (P<0.05). The fracture toughness of the DLP group was (7.22±0.81) MPa·m1/2, which was not statistically different from that of the MILL group (P>0.05).

Conclusion

Zirconia manufactured by DLP 3D printing had microstructure and mechanical properties similar to those of the milled zirconia. Only the flexural strength and the Vickers hardness of the experimental zirconia were slightly lower than those of the milled zirconia. Therefore, DLP-manufactured zirconia has a promising future for clinical use.

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Force balance reconstruction of orbicularis oris in correction of unilateral cleft lip deformity
Chen Yu, Liu Yingmeng, Zhang Bihe, Zheng Qian, Shi Bing, Li Chenghao
West China Journal of Stomatology    2021, 39 (6): 698-702.   DOI: 10.7518/hxkq.2021.06.011
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Objective

Short-term outcome evaluation for the correction of unilateral cleft lip deformity with a new technique.

Methods

Forty-four patients with unilateral cleft lip deformity were included in the study and in which the orbicularis oris muscle was reconstructed to achieve the optimal force balance of reconstructed orbicularis oris. The photometric two-dimensional indexes, including the philtrum oblique angle and asymmetry ratios (lip height, lip width, vertical distance from the white roll to the vermilion bottom at the Cupid’s bow point, and vertical distance from the Cupid ’s bow points to facial midline), were employed to measure and evaluate the outcome.

Results

Several indexes showed statistically significant difference, and they included the philtrum oblique angle, asymmetry ratio of the lip height, and asymmetry ratio of the vertical distance from the white roll to the vermilion bottom at Cupid ’ s bow points (P<0.05).

Conclusion

The results suggested that the new muscle reconstruction technique can significantly improve the short-term outcome of the correction of unilateral cleft lip deformity.

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Evaluation of the postoperative effect of computer-assisted free fibula mandibular reconstruction
Kang Zebiao, Mai Xiaoxue, Wang Xin, Xie Fuqiang
West China Journal of Stomatology    2022, 40 (2): 189-196.   DOI: 10.7518/hxkq.2022.02.010
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Objective

This study aims to establish a standardized, repeatable, and simple digital evaluation method for accurately determining the effect of computer-assisted free fibula mandibular reconstruction.

Methods

A total of 20 mandibular defect cases caused by tumors were analyzed retrospectively. The coronal, sagittal, and axial mandibular angles were measured and analyzed with Mimics Research 21.0 and 3-matic Research 13.0 software before and after surgery. The effect of computer-assisted free fibula mandibular reconstruction was evaluated.

Results

No significant difference was observed in the coronal and axial mandibular angles between the healthy and affected sides before operation (P>0.05). By contrast, a significant difference in sagittal mandibular angle (P<0.05) was noted. No significant difference was found in the coronal, sagittal, and axial mandibular angles between the healthy and affected sides after operation (P>0.05). Conversely, a significant difference was recorded in the absolute value of the coronal, sagittal, and axial mandibular angles between the healthy and affected sides pre-operation and post-operation (P<0.01). Meanwhile, a significant difference was observed in the sagittal mandibular angle between the healthy and affected sides before operation and the axial mandibular angle between the healthy and affected sides after operation in Type Ⅰ defect (P<0.05). Moreover, no significant difference in the 3D mandibular angle was found between the healthy and affected sides before and after operation in other types (P>0.05). Furthermore, no significant difference was recorded in the absolute values of the sagittal and coronal mandibular angles between the healthy and affected sides before and after operation in Type Ⅰ defect (P>0.05). Lastly, a significant difference was found in the absolute values of the 3D mandibular angles between the healthy and affected sides before and after operation in other types (P<0.05).

Conclusion

Computer-assisted free fibula mandibular reconstruction can significantly improve 3D mandibular deformities caused by tumors and effectively restore the accurate symmetry of the mandibular anatomical structure. The evaluation method used in this study can accurately evaluate the effects of mandibular reconstruction and provide guidance to preoperative design.

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Short-term efficacy of superficial X-ray treatment for infantile maxillofacial hemangioma
Tang Lina, Liu Gang, Yang Chao, Sha Xiaowei, Wang Siyu
West China Journal of Stomatology    2021, 39 (4): 464-468.   DOI: 10.7518/hxkq.2021.04.014
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Objective

This study aimed to explore the short-term clinical efficacy and factors influencing low-dose superficial X-ray for treating infantile maxillofacial hemangioma.

Methods

Retrospective analysis was conducted on 161 cases of infants with maxillofacial hemangioma treated with superficial X-ray in the Laser Center of Dermatology Department of Sichuan Provincial People's Hospital from January 2015 to December 2017. Clinical efficacy was analyzed by comparing the photos before and after treatment. Patients were further divided into groups according to different genders, age at the start of treatment, preterm birth or low birth weight, hemangioma site, longest diameter of hemangioma, and type of hemangioma to analyze whether differences existed in clinical efficacy and therapeutic dose between different groups.

Results

Twelve months after the end of treatment, the overall cure rate was 93.8%, and the significant efficiency was 97.5%. The clinical efficacy was related to the age of children at the beginning of treatment and the type of hemangioma (P<0.05). The clinical efficacy of children aged less than or equal to 12 months and superficial hemangioma group was better than that of children aged more than 12 months and deep subtype or mixed hemangioma group, respectively. Therapeutic doses associa-ted with hemangioma treatment with diameter, category, age (P<0.05), diameter greater than or equal to 4 cm hemangioma group, the mixed type or deep in the group, the children older than 12 months hemangioma group, respectively, the dia-meter is less than 4 cm hemangioma, superficial hemangioma group and age less than or equal to 12 months hemangioma total treatment group exposure dose is greater.

Conclusion

Low-dose superficial X-ray is safe and effective for the treatment of infantile maxillofacial hemangioma. Age and type of hemangioma at the time of treatment are the factors influencing therapeutic dose and clinical efficacy.

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Effect of piceatannol against malignant melanoma in vivo and in vitro
Yu Bo, Liu Wei, Hu Minqi, Tang Xiufa, Li Chunjie, Que Lin
West China Journal of Stomatology    2021, 39 (4): 413-418.   DOI: 10.7518/hxkq.2021.04.006
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Objective

To study the antitumor effect of piceatannol (PIC) on malignant melanoma in vitro and in vivo.

Methods

B16F10 cells were cultured in vitro and treated with gradient concentrations of PIC. Cell viability was detected with methyl thiazolyl tetrazolium (MTT) assay; matrix metalloproteinase (MMP)-2, MMP-9, vascular endothelial growth factor (VEGF), spleen tyrosine kinase (Syk), and p-Syk were detected with Western blot; migration ability was detected with wound healing assay; invasion ability was detected with Transwell assay. Syk expression was suppressed through RNA interference for the detection of the possible mechanism of PIC in melanoma. An in vivo study was established by creating B16F10-bearing mice with intraperitoneal injection of PIC.

Results

The cell viability of B16F10 decreased with increasing PIC concentration. The results of the Transwell assay showed that invasion ability decreased with increasing PIC concentration, and healing time was prolonged at increased PIC concentration in the wound healing assay. Western blot results showed that PIC mainly inhibited the phosphorylation of Syk and inhibited the expression of MMP-2, MMP-9, and VEGF. RNA interference pointed out that blocking the expression of Syk can reveal the same inhibition effect on B16F10 cells as PIC. In vivo study revealed that different concentrations of PIC cangreatly inhibit melanoma progression.

Conclusion

PIC might block the progression of malignant melanoma by inhibiting spleen tyrosine kinase.

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Prospect on the application of mesenchymal stem cell-derived extracellular vesicles in the regeneration of dental and maxillofacial tissues
Liao Li, Tian Weidong.
West China Journal of Stomatology    2022, 40 (1): 7-13.   DOI: 10.7518/hxkq.2022.01.002
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Extracellular vesicles (EVs) are the essential mediators of communication between different cells or tissues. EVs participate in the development, homeostasis, repair, and regeneration of tissues. Mesenchymal stem cells(MSCs) secrete a range of bioactive factors, which are important in MSC-mediated tissue regeneration. Great progress has been made in the research of EVs derived from MSCs (MSC-EVs) in the regeneration of dental and maxillofacial tissues. Emerging evidence confirmed that MSC-EVs can efficiently modulate the proliferation, differentiation, survival, and migration of stem or progenitor cells and stimulate the regeneration of the neurovascular system. MSC-EVs have been used in regenerating dental pulp, periodontium, jawbone, temporomandibular joint, and maxillofacial soft tissues. Having the advantages of low immunogenicity, versatile function, and suitability for large-scale production, EVs have excellent clinical application prospect. Along with investigations on molecular mechanisms of action and development of standard manufactory and testing systems, therapies u-sing MSC-EVs are promising strategies for regenerating dental and maxillofacial tissues.

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Use of two kinds of antioxidants to restore the bond strength of bleached enamel
Xu Yingxin, Li Wen, Su Min
West China Journal of Stomatology    2021, 39 (4): 453-457.   DOI: 10.7518/hxkq.2021.04.012
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Objective

This work aimed to evaluate the ability of two kinds of antioxidants, namely, grape-seed extract and sodium ascorbate, in restoring bond strength at the resin-enamel interface after bleaching.

Methods

Ten groups of samples with 15 teeth per group were prepared for shear-bond-strength test at the resin-enamel interface after bleaching. The groups were as follows: control; no antioxidant; 2.5%, 5%, 10%, or 15% grape-seed extract; and 2.5%, 5%, 10%, or 15% sodium ascorbate. The peak values of shear bond strength when resin was debonded from teeth and the failure modes under a microscope were recorded. Ten other groups of teeth with two teeth per group were prepared and treated in a similar approach before resin bonding. The samples were cut vertically to the bonding interface. The structures of the bonding interface were compared by scanning electron microscopy.

Results

No statistically significant difference in shear bond strength was found among the no-antioxidant, 2.5% grape-seed extract, and 2.5%, 5%, or 10% sodium ascorbate groups (P>0.05), which were statistically significantly lower than the control group (P<0.05). Evidence of marginal gap was observed at the resin-enamel interface, and resin tags in enamel were short, poorly defined, and fragmented. No statistically significant difference in shear bond strength was found among 5%, 10%, or 15% grape-seed extract, 15% sodium ascorbate, and control groups (P>0.05). No evidence of discontinuity was found at the adhesion interface, and resin tags in enamel were long, well defined, and structurally intact. Failure in the adhesive joint was the major debond mode in all experimental groups.

Conclusion

Immediately after bleaching, the bond strength of dental enamel significantly decreased. Bond strength can be restored by 5% grape-seed extract or 15% sodium ascorbate in 5 min.

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Targeting-YAP/TAZ therapies for head and neck cancer, directly or indirectly?
Feng Xiaodong.
West China Journal of Stomatology    2021, 39 (5): 493-500.   DOI: 10.7518/hxkq.2021.05.001
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YAP/TAZ are wild over-activated in head and neck squamous cell carcinoma (HNSCC) with high potential as a direct therapy target for HNSCC treatments. However, the efforts on the directly targeting-YAP/TAZ therapies over the past decade, have very limited impacts, mainly caused by: 1. There is still none effective and specific YAP/TAZ inhibitor with clinical potential; 2. YAP/TAZ might not be directly targeted, because of their multiple important biological functions, such as: regulation of cell proliferation and survival, stem cell maintain, regulation of organ development, organ size control, and tissue regeneration. Interestingly, the over-activation of YAP/TAZ in HNSCC mainly be regulated by upstream abnormal molecular or biological events, instead of genes alteration of YAP/TAZ. Therefore, exploring the alternative molecular events regulating YAP/TAZ activation and molecular mechanism in HNSCC might help to uncover novel indirect targets of YAP/TAZ therapies for HNSCC prevention and treatment.

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Application of vascularized mucosal flap for early-medium-term tongue cancer and floor of mouth cancer defect repair: a preliminary study
Jiang Yueyun, Tang Lingling, Ma Zhongkai, Liu Wei, Huang Nengwen, Li Chunjie
West China Journal of Stomatology    2022, 40 (2): 204-209.   DOI: 10.7518/hxkq.2022.02.012
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Objective

This study aimed to assess the efficacy and safety of facial artery musculomucosal (FAMM) flap for small-medium tongue or floor of mouth defects caused by surgical resection of early-medium stage tongue or floor of mouth cancer.

Methods

A retrospective cohort study was conducted and included patients with early-medium stage tongue or floor of mouth cancer and reconstructed by FAMM flap or traditional free or axial flaps. Demographic data and surgery-related data were collected. Patients were followed up for 6 months and evaluated with satisfaction, maximal mouth opening, satisfactory contour and speech, and oral intake function at months 3 and 6.

Results

Forty-five patients were included, with 15 in the FAMM group and 30 in the flap group. All patients finished 3 months follow-up, and 1 in each group was lost to follow-up at month 6. All followed-up patients had no recurrence or metastasis. The FAMM group had a significantly shorter surgical time than the flap group (P<0.05). The flap group had significantly more donor sites that were uncomfortable compared with the FAMM group (P<0.05). There was no statistical significance on satisfaction, but the FAMM group had better outcomes on contour, speech, and oral intake function at month 6 than the flap group (P<0.05). The FAMM group had smaller maximal mouth opening than the flap group (P<0.05) at month 3 but equivalent maximal mouth opening at month 6 (P>0.05).

Conclusion

FAMM flap has some advantages for small-medium tongue or floor of mouth defects caused by surgical resection of early-medium stage tongue or floor of mouth cancer, and it could be an ideal choice for clinical application.

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circ_0005379 inhibits the progression of oral squamous cell carcinoma by regulating the miR-17-5p/acyl-CoA oxidase 1 axis
Zhou Haixia, Wang Luyao, Chen Shuai, Wang Dandan, Fang Zheng
West China Journal of Stomatology    2021, 39 (4): 425-433.   DOI: 10.7518/hxkq.2021.04.008
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Objective

To investigate the effects of circ_0005379 on the proliferation, apoptosis, migration, and invasion of oral squamous cell carcinoma (OSCC) cells and its mechanism.

Methods

Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression levels of circ_0005379 and miR-17-5p in OSCC tissues and SCC15 cell lines. Western blot was used to detect the expression levels of acyl-CoA oxidase 1 (ACOX1). The circ_0005379 overexpression vector was transfected into SCC15 cells. Methyl thiazolyl tetrazolium blue staining, flow cytometry, Transwell, and Western blot were used to detect the effects of circ_0005379 overexpression on the proliferation, apoptosis, migration, and invasion of SCC15 cells and the expression of E-cadherin, β-catenin, and Snail proteins. Dual luciferase reporter assay and RNA immunoprecipitation were used to examine the regulation of circ_0005379, miR-17-5p, miR-17-5p, and ACOX1 in SCC15 cells. A nude mouse xenograft model of SCC15 cells stably overexpressing circ_0005379 was established, and the effect of circ_0005379 overexpression on the growth of xenografts in nude mice was observed.

Results

Compared with adjacent cancer tissues, the expression levels of circ_0005379 and ACOX1 proteins in OSCC tissues were decreased (P<0.05), and the expression level of miR-17-5p was increased (P<0.05). Compared with HOK-16A cells, the expression levels of circ_0005379 and ACOX1 proteins in SCC15 cell lines were decreased (P<0.05), and the expression level of miR-17-5p was increased (P<0.05). After overexpressing circ_0005379, the activity and number of migrating and invading SCC15 cells and the expression levels of β-catenin and Snail proteins were decreased (P<0.05); however, the apoptosis rate and expression level of E-cadherin protein were increased (P<0.05). In SCC15 cells, circ_0005379 targeted the negative regulation of miR-17-5p expression, and miR-17-5p targeted the negative regulation of ACOX1 expression. Overexpressing miR-17-5p or silencing ACOX1 could reverse the effects of circ_0005379 overexpression on the proliferation, apoptosis, migration, and invasion of OSCC cell lines. The tumor volume and weight of nude mice overexpressing circ_0005379 were decreased (P<0.05), the expression levels of circ_0005379 and ACOX1 protein in tumor tissues were increased (P<0.05), and the expression level of miR-17-5p was decreased (P<0.05).

Conclusion

circ_0005379 may inhibit the proliferation, migration, and invasion of OSCC cells by downregulating the expression of miR-17-5p and upregulating ACOX1, which promote apoptosis and inhibit tumor growth in vivo. circ_0005379 may be a potential target for OSCC treatment.

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Gingival plasma cell granuloma: a case report
Chen Dihui, Zhao Hanqing, Jia Baolong, Yang Rongyu, Duan Kaiwen
West China Journal of Stomatology    2022, 40 (1): 100-105.   DOI: 10.7518/hxkq.2022.01.015
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Plasma cell granuloma is extremely rare in the oral cavity. This paper reports a case of plasma cell granuloma in the oral cavity and reviews the literature. In this case, the plasma cell granuloma occurred in the gingiva, which was bright red and granular. The lesion was resected and diagnosed as gingival plasma cell granuloma by clinical pathological examination. Four months follow-up after operation surgery showed no signs of recurrence. Although gingival plasma cell granuloma is rare, it is easily confused with related diseases and should be identified and followed up closely.

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Guided bone regeneration-assisted orthodontic treatment for closing the space of missing central incisors
Chen Luyi, Huang Min, Wu Jiaqi, Luo Jun
West China Journal of Stomatology    2021, 39 (4): 482-488.   DOI: 10.7518/hxkq.2021.04.017
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Long-term missing teeth can lead to alveolar bone loss in the edentulous area. Guided bone regeneration (GBR) is a bone augmentation method. It is widely used in clinical practice and broadens the indications of orthodontic treatment to a certain extent. This article reports a case of an adult patient with edentulous space in the maxillary central incisor, which was successfully closed through orthodontic treatment combined with GBR. This study will provide a re-ference for future clinical work.

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Clinical application of double-layer soft tissue closure technology based on pedicled buccal fat pad in repairing maxillary defects after medication-related osteonecrosis of jaw surgery
Guo Yuxing, Zhao Ning, Wang Diancan, Wang Yang, Guo Chuanbin
West China Journal of Stomatology    2022, 40 (1): 61-67.   DOI: 10.7518/hxkq.2022.01.009
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Objective

This study aimed to analyze the clinical application effect of the double-layer soft tissue closure technique (DLST) based on pedicled buccal fat pad in repairing maxillary defects after medication-related osteonecrosis of the jaw (MRONJ) surgery.

Methods

Ten patients with maxillary MRONJ were diagnosed and treated via DLST based on pedicled buccal fat pad. Partial maxillary resection was conducted to remove the MRONJ lesion, and the inflammatory soft tissue in the maxillary sinus cavity was removed but the maxillary sinus mucosa was retained. Patients also underwent resection of the lower segment of the sphenoid pterygoid process. A pedicled buccal fat pad was used to line the maxillary sinus floor and oral mucosa to achieve double-layer soft tissue closure of the wound. The characteristics of the medication for the primary disease, the clinical characteristics and imaging characteristics of osteonecrosis, the surgical treatment effects, pain score, and functional status evaluation of the 10 patients were all reviewed and analyzed.

Results

Among the 10 patients, there were 5 cases of breast cancer, 2 cases of lung cancer, 1 case of prostate cancer, 1 case of multiple myeloma, and 1 case of kidney cancer. All 10 patients received zoledronic acid, and the average time of application of zoledronic acid was 34 months. Six patients had upper jaw exposure, and 4 patients had gingival soft tissue fistula; the average time to clinical symptoms was 5.6 months. Among them, 5 patients had a history of tooth extraction, 3 patients with apical periodontitis, 1 patient with periodontitis, and 1 patient with spontaneous teeth loss. The lesions of 10 patients were all located in the maxillary posterior area. CT images can often show sequestration near the maxillary sinus floor, and the maxillary sinus cavity was full of soft tissue inflammation in most patients. During the follow-up period, 8 patients healed by the first intention, and the other patient had partial liquefaction of the buccal fat pad 2 weeks after the operation, and the oral mucosa fistula closed 1 month after the operation. In another patient, MRONJ symptoms recurred 2 months after the operation, and the surgical site occasionally swelled and discharged pus. The patient’s symptoms were completely relieved after another operation. The patient’s pain and functional status improved significantly after the operation.

Conclusion

Maxillary MRONJ is commonly found in the posterior area. The buccal fat pad-based DLST is used to repair the defect after maxillary resection, which is beneficial to seal the oral-maxillary sinus fistula and improve the clinical symptoms of patients with MRONJ.

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Detection of peripheral blood circulating tumor cells in oral squamous cell carcinoma and its clinical significance
Zhang Shuaiyuan, Qin Shuo, Li Guanghui, Yi Yaqun, Fu Haojie, Gao Yajing, Sun Minglei.
West China Journal of Stomatology    2021, 39 (5): 591-597.   DOI: 10.7518/hxkq.2021.05.015
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Objective

This study aims to investigate the diagnostic value of peripheral blood circulating tumor cells (CTCs) in oral squamous cell carcinoma (OSCC) and its correlation with the clinicopathological features of OSCC.

Methods

Ninety-three patients diagnosed as OSCC in the First Affiliated Hospital of Zhengzhou University from May 2019 to May 2020 were selected as the experimental group, and 20 healthy volunteers were employed as the control group. The CTCs value of peripheral blood of the patients were measured by CTCs detection technology, and its clinical significance was analyzed.

Results

The CTCs values in the experimental group were higher than those in the control group, and the difference was statistically significant (P<0.000 1). The CTCs value in the peripheral blood of patients in the experimental group were not correlated with gender, site of onset, and presence or absence of peripheral tissue infiltration (P>0.05), but was correlated with age (P=0.022), tumor T stage (P=0.02), tumor N stage (P=0.007 5), tumor M stage (P=0.013), clinical stage (P=0.029), early or late stage (P=0.022), tumor differentiation degree (P<0.001), and node metastasis (P=0.006 4). The AUC value of CTCs in OSCC diagnosis was 0.925, and the energy efficiency was statistically significant [P=0.000, 95%CI (0.876, 0.974)]. When the CTC value was 8.450 FU/3 mL, the maximum value of the Yoden index was 0.853, and the sensitivity and specificity of OSCC diagnosis were 90.3% and 95.0%, respectively. The AUC value of CTCs in the diagnosis of OSCC metastasis was 0.691, and the energy efficiency was statistically significant [P=0.000, 95%CI (0.580, 0.803)]. When the blood CTC value was 12.250 FU/3 mL, the maximum value of Yoden index was 0.367, the sensitivity was 63.6%, and the specificity was 73.3%. Multivariate regression analysis showed that buccal tumor was negatively correlated with CTCs in patients with OSCC (P=0.001 08), N2 stage (P=0.000 74) and M stage (P=0.026 38). High differentiation (P<0.000 1) and moderate differentiation (P=0.001 5) were negatively correlated with CTCs values in patients with OSCC.

Conclusion

Peripheral blood CTCs has important clinical value for early screening, auxiliary diagnosis, evaluation of metastasis, and determination of malignant degree, progression, and pathological grade of OSCC and a relatively reliable tumor detection indicator.

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