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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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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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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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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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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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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.

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Digital partition bonding for porcelain veneers guided by sequence 3D printing templates
He Jinxiu, Gao Jing, Liu Chunxu, Xie Chenyang, Yu Jiayi, Yu Haiyang.
West China Journal of Stomatology    2022, 40 (3): 365-369.   DOI: 10.7518/hxkq.2022.03.019
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Obtaining optimal enamel bonding is a common recommendation to ensure the retention, edge closure, and clinical service life of porcelain veneers. Bonding surface is determined after tooth preparation. More or less dentin exposure often occurs due to the uneven thickness of the enamel. Identifying the enamel or dentin on the bonding surface and adopting the “selective etching” technique are useful to obtain the maximal bonding strength. Naked eye recognition in “selective etching” has uncertain results and is experience-based, whereas the proposed technique controls the preparation depth through the first target restoration space template to obtain the accurate enamel and dentin subarea. It is mapped to the second bonding template, depending on the treatment carried out on the enamel and dentin surface, to accurately predict the adhesion of porcelain veneers.

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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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Expert consensus on clinical management for early childhood caries
Zhang Qiong, Wang Jun, Xia Bin, Zhao Wei, Chen Xu, Jiang Beizhan, Huang Yang, Wu Li’an, Yuan Guohua, Zou Jing
West China Journal of Stomatology    2022, 40 (5): 495-503.   DOI: 10.7518/hxkq.2022.05.001
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Early childhood caries (ECC) is the most prevalent chronic oral disease and one of the worldwide public health problems of great urgency for children. ECC can affect children's teeth, dentition, craniomaxillofacial, and general health and development. Therefore, through dental caries etiologies and caries risk assessment, patient-centered, personalized planning and a combination of prevention and treatment should be implemented in the clinical management for ECC. Periodic and continuous cycle management can only be accomplished with the cooperation of medical staff, children, and their guardians. This expert consensus will expound the clinical management of ECC in the following aspects: caries risk assessment, early clinical prevention, treatment strategies, and postoperative management.

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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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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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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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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 changes in orbital volume in adult female patients with maxillary transverse deficiency treated with a maxillary skeletal expander
Shi Xiaoyang, Lin Xuefen, Ma Chi, Chen Muhan, Liu Dongxu.
West China Journal of Stomatology    2022, 40 (3): 314-319.   DOI: 10.7518/hxkq.2022.03.011
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Objective

The effects of using a maxillary skeletal expander (MSE) on the orbital volume and width between periorbital bones in the treatment of adult female patients with maxillary transverse deficiency (MTD) were evalua⁃ted.

Methods

A total of 20 adult female patients with MTD with an average age of (22.60±6.29) years were included in the study. The patients were treated with MSE. Cone beam computed tomography was performed before expansion (T0) and no more than 3 weeks after expansion (T1). Orbital volume and periorbital bone width were measured with Mimics 21.0 and analyzed with SPSS 20.0. Paired t-test was performed, and a P value of <0.05 indicated significant difference.

Results

After expansion, the orbital volume increased by (346.80±275.31) mm3 (P<0.05). The width between the right and left zygomaticomaxillary sutures increased by (1.69±0.57) mm (P<0.05), and the width between the right and left infraorbital points increased by (1.71±0.70) mm (P<0.05). However, the width between the right and left frontozygomatic sutures increased by (0.15±0.32) mm (P>0.05). Finally, the width between the right and left supraorbital points increased by (0.23±0.52) mm (P>0.05).

Conclusion

The maxillary skeletal expander slightly expanded the orbital volume in the adult female patients and increased the lateral widths of the periorbital bones.

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Clinical decision-making of anterior implant abutment
Yu Haiyang, Sun Manlin, Wang Zhongyi.
West China Journal of Stomatology    2022, 40 (5): 504-512.   DOI: 10.7518/hxkq.2022.05.002
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Abutment is an important component serving as a connecting link between the implant and the implant-supported prosthesis. In accordance with mechanical, biological, and other conventional norms, it can compensate the deviation between the implant and the prosthesis, which plays a significant role in maintaining the health of peri-implant tissue and the longevity, stability, and effectivity of prosthesis. However, choosing an anterior implant abutment correctly and conveniently is challenging, given the great variety of anterior abutment in clinical practice. Through virtual implant design, the correct implant site was compared and selected, and the supra-target prosthesis was coordinated before and after the operation. The implant level vertical of height of target restoration space (I) was measured to predict the availability and the retentive method of the implant restoration. After implantation, the primary selection of abutment type was selected according to the implant system (S), screw access position, and retentive method of the prosthesis. The final selection of abutment is accomplished by combining the measured values of peri-implant soft tissue thickness (T), gingival height (GH), and long axis of implant (L). Furthermore, the concepts and the classified applications of custom abutment were discussed in detail in this paper. The plan's main control variables L, I, GH, T, and S compose the words Lights, so this plan can be abbreviated as the anterior abutment decision tree. The decision tree has good decision-making efficiency and high clinical accessibility.

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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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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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Comparison of surgical effects between the modified West China method and Millard method in repairing unila-teral cleft lip
Liu Xiaolin, Wang Yu, Feng Xiaowei, Liu Wenjing, Li Xiangjun.
West China Journal of Stomatology    2022, 40 (3): 309-313.   DOI: 10.7518/hxkq.2022.03.010
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Objective

The purpose of this study is to compare the surgical effects of the modified West China method and Millard methods for repairing unilateral cleft lip.

Methods

A total of 34 cases of unilateral cleft lip were analyzed, composed of 16 cases in the experimental group subjected to the modified West China method and 18 cases in the control group, which was subjected to the Millard method. Photographs before and after operation were compared, and SPSS 21.0 was used in statistical analysis.

Results

After operation, no significant difference in symmetry between the healthy and affected sides of the nasal alar foot (sba), nasal alar point (al), lip peak point (cph), and mouth angle point (ch) in the experimental group (P>0.05), but no significant difference in symmetry was found between healthy and affected sides of cph and ch in the control group (P>0.05). No significant differences in the symmetry rates of the sba, cph, ch and the nasal columella regression rates were found between the experimental and control groups (P>0.05). The symmetry rates of the al in the experimental group were higher (P<0.05).

Conclusion

For unilateral cleft lip repair, two methods had better effects on lip repair, but the nasal symmetry showed greater improvement when the modified West China me-thod was used than when the Millard method was used.

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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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Comparative study on the influence of anterior and posterior scars of hard palate on maxillary growth after cleft palate surgery: a three-dimensional finite element analysis
Huang Wei, Zhang Xiao, Li Man, Ning Chunliu, Wu Shanshan, Li Xiangjun
West China Journal of Stomatology    2022, 40 (2): 210-217.   DOI: 10.7518/hxkq.2022.02.013
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Objective

This study aimed to compare the inhibition of anterior and posterior scars of the hard palate on maxillary growth after cleft palate surgery.

Methods

Ansys was used to establish two 3D finite element models of maxilla with complete and incomplete cleft palate. The palatal scar force with same magnitude and direction but different areas was applied in four groups in the two models. The loading force was applied to 1/4 of the anterior oral surface of the hard palate (group 1), 1/4 of the middle and anterior oral surface of the hard palate (group 2), 1/4 of the middle and posterior oral surface of the hard palate (group 3), and 1/4 of the posterior oral surface of the hard palate (group 4). The displacement of each group after loading was analyzed and compared.

Results

In the two models, maxillary deformation occurred in all groups. The total displacement and 3D displacement comparison of each group was arranged as follows: group 1>group 2>group 3>group 4.

Conclusion

Scars from different parts of the hard palate after cleft palate surgery can inhibit maxillary growth in a 3D direction. The anterior scars have more serious inhibition than the posterior scars.

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Application of digital guide plate based on drill-hole sharing in oral and maxillofacial surgery
Wang Lidong, Ma Wen, Fu Shuai, Zhang Changbin, Cui Qingying, Peng Canbang, Li Ming.
West China Journal of Stomatology    2022, 40 (1): 68-74.   DOI: 10.7518/hxkq.2022.01.010
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Objective

This study aimed to investigate the application of digital guide plate based on the drill-hole sharing concept in orthognathic surgery and mandibular reconstruction.

Methods

Sixteen patients with maxillofacial deformity requiring orthognathic surgery and 10 patients requiring mandibular reconstruction were selected as the research objects. Patients with maxillofacial deformity were scanned by computed tomography (CT), gypsum mold of the maxilla and mandibular arch were scanned using a laser surface scanner, and the fibula or iliac bone of the patients who needed mandibular reconstruction were scanned by CT to create a 3D model. The osteotomy and repositioning guides based on the drill-hole sharing concept were manufactured by digital technology. The guide plate was used to guide osteotomy and reposition the bone segment. Postoperative CT scan was performed. The displacement error of the bone segment was compared between the preoperative virtual surgery and the actual surgery to evaluate the accuracy of the guide plate, by measuring the distance between the landmarks and three reference planes and the distance between the two landmarks.

Results

The wounds healed well in all patients, and no serious complications were observed. The maximum mean values of LeFort Ⅰ osteotomy, genioplasty, fibular reconstruction, and iliac reconstruction were 0.84, 0.64, 1.27, and 1.18 mm, respectively; these values were acceptable by clinical standards.

Conclusion

The digital guide plate based on the drill-hole sharing concept has high accuracy and clinical application value in orthognathic surgery and mandibular reconstruction.

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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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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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Porphyromonas gingivalis upregulates calbindin 1 and thus promotes the proliferation of gingival epithelial cells
Zhang Yuwei, He Yuxuan, Ding Yi, Liu Chengcheng.
West China Journal of Stomatology    2022, 40 (1): 93-99.   DOI: 10.7518/hxkq.2022.01.014
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Objective

This study aims to investigate the effect of calbindin 1 on the proliferation and apoptosis of gingival epithelial cells affected by Porphyromonas gingivalis (P. gingivalis)invitro.

Methods

A model of P. gingivalis infecting CA9-22 was established in vitro. At 24 h after infection, the expression of calbindin 1 (CALB1) was detected by real-time fluorescent quantitative polymerase chain reaction, Western blot, and immunofluorescence analyses. The expression of CALB1 was further inhibited by RNA interference. Cell proliferation was detected by BrdU analysis, and cell apoptosis was detected by caspase 3 activity. The expression of MDM2 and p53 was detected by Western blot analysis.

Results

P. gingivalis infection upregulated the expression of CALB1 in CA9-22 cells with multiplicity-dependent manner. CALB1 promoted the proliferation of CA9-22 cells, increased the expression of MDM2, and inhibited the expression of p53. Inhibiting CALB1 expression did not affect the inhibitory effect of P. gingivalis infection on CA9-22 apoptosis.

Conclusion

P. gingivalis infection can promote the proliferation of CA9-22 cells by increasing CALB1 expression. The related mechanism may be associated with MDM2-p53.

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Surgical design and application of alar cartilage positioning and repositioning in correcting cleft lip nose deformity
Li Jingtao, Shi Bing.
West China Journal of Stomatology    2022, 40 (2): 134-138.   DOI: 10.7518/hxkq.2022.02.002
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Correction of nasal deformity is integral to modern cleft lip repair, and high risk of postoperative relapse remains a technical hurdle to overcome. The authors previously presented internal fixation of alar cartilage based on Chinese nasal morphology and lateral columella tissue increment for the correction of unilateral cleft nose deformity. Through the application and review of these techniques, the authors developed a new technique named alar cartilage positioning for primary cleft nose correction, or alar cartilage repositioning for secondary cases. Here, we introduce the theoretical foundation and preliminary experience in using this new technique.

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Comparing accuracy after guide access and microscope-assisted access for fiber post removal
Cai Pingping, Chen Xi, Jiang Yi, Lu Zhaojie, Lin Jie, Zheng Zhiqiang.
West China Journal of Stomatology    2022, 40 (3): 297-302.   DOI: 10.7518/hxkq.2022.03.008
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Objective

This study compared the accuracy of the guide-supported and the microscope-assisted fiber post removal systems by using the extracted teeth. These new idea and theory can be used by clinicians to remove fiber posts.

Methods

Twenty-eight human extracted premolars were randomly divided into the guide and microscope groups. After root canal treatment and fiber post restoration, the fiber posts were removed by using a digital guide and via microscope-assisted ultrasonic instrument, respectively. Mimics 10.0 was used to measure the deviation, and the accuracy of the two fiber post removal systems were compared.

Results

In the guide group, the apical vertical deviation was 0.99 mm±0.52 mm, the apical horizontal deviation was 0.75 mm±0.19 mm, the angle deviation was 2.32°±0.64°, and the volume loss was 8.09 mm3±1.42 mm3. In the microscope group, the apical vertical deviation was 0.44 mm±0.23 mm, the apical horizontal deviation was 0.23 mm±0.07 mm, the angle deviation was 0.64°±0.31°, and the volume loss was 15.25 mm3±3.94 mm3. No significant difference was found in the apical vertical deviation between the two groups (P>0.05), whereas the apical horizontal deviation, the angle deviation, and the volume loss were significantly different between the two groups (P<0.05).

Conclusion

The removal of fiber post supported by a digital guide helped reduce the volume loss of post-core restoration teeth, but its accuracy was lower than that of removal by using a microscope-assisted ultrasonic instrument.

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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.

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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.

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Clinical observation of a narrow alveolar ridge in the anterior area with a simple taper retention implant
Gong Jinmei, Xia Xun, Hu Changqi, Huang Jiangqin, Guo Shuigen, Wei Hongwu.
West China Journal of Stomatology    2022, 40 (2): 175-182.   DOI: 10.7518/hxkq.2022.02.008
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Objective

This study aims to determine the clinical effect of an external attachment implant, called JUST J1 MINI (hereafter referred to as J1 implant), with simple tonal retention on the narrow alveolar area of the anterior teeth (4.5-5.5 mm).

Methods

A total of 27 J1 implants were implanted in 12 patients in the Fourth Affiliated Hospital of Nanchang University who were treated with narrow alveolar ridge implants. In the absence of any bone increment, all the implants were implanted with tonal retention external connection, and the survival rate of the implants was evaluated using Wheeler retention standard. The average observation period was 24 months. The amount of bone absorption at the edge of the implant, abutment abscission rate, and fracture/fracture and loosening of the implant were observed.

Results

The marginal bone uptake of the 27 J1 implants in 12 patients was (0.069±0.032) mm 6 months after implantation and (0.142±0.079) mm 24 months after implantation. No significant difference in marginal bone uptake was observed between the implants 6 months and 24 months after implantation. No loosening of the abutment was found, and implant retention rate was 100% during the observation period.

Conclusion

The application of JUST J1 MINI to the narrow alveolar ridge in the anterior area can achieve a simple aesthetic effect within a short period under the condition of no bone increment.

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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.

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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.

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Oral cancer cells affect pancreatic β-cell function through transmissible endoplasmic reticulum stress
Li Ruohan, Huang Yingzhao, Liao Nailin, Wu Chenzhou, Li Yi.
West China Journal of Stomatology    2022, 40 (1): 22-31.   DOI: 10.7518/hxkq.2022.01.004
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Objective

In this study, we aimed to investigate whether oral cancer cells affect pancreatic β-cells function through transmissible endoplasmic reticulum stress (TERS).

Methods

Tunicamycin (TM) was selected as the endoplasmic reticulum stress (ERS) inducer. The human oral cancer cell lines CAl-27 and SCC-25 were selected as the donor cells, and mouse insulinoma 6 (MIN6) cell lines were chosen as the recipient cells. Quantitative real-time polymerase chain reaction (qPCR) and Western blot (WB) analysis were used to detect ERS markers and insulin expression. The TdT-mediated dUTP nick-end labeling (TUNEL) method was applied to detect apoptosis levels. The clone formation method was utilized to detect cell proliferation capability. The secretory function of pancreatic β-cells was detected with an enzyme linked immunosorbent assay (ELISA) kit and a bicinchoninic acid (BCA) kit.

Results

The MIN6 cells were subjected to TM stimulation. qPCR and WB analysis revealed that ERS markers were upregulated. This result implied that the MIN6 cells can induce ERS. The supernatant of oral cancer cells under ERS was added to the MIN6 cells. qPCR and WB analysis showed that the oral cancer cells that had been subjected to ERS could induce ERS in the MIN6 cells, that is, the phenomenon of TERS occurred. The TUNEL assay indicated that the apoptosis of the MIN6 cells increased under TERS. The clone formation assay demonstrated that the proliferation capability of the MIN6 cells decreased under TERS. qPCR and WB analysis revealed that under TERS, insulin synthesis by the MIN6 cells decreased and insulin synthesis was inhibited at the translation level. The ELISA and BCA kits demonstrated that insulin secretion by the MIN6 cells was reduced under TERS.

Conclusion

Oral cancer cells can affect pancreatic β-cells through TERS, resulting in increased apoptosis, decreased viability, and reduced insulin secretion and synthesis capability.

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A case of precise prosthesis under the direction of target restoration space analysis after multidisciplinary combination therapy
Yang Leining, Qin Hanglin, Zhang Jing, Han Xiaopeng
West China Journal of Stomatology    2022, 40 (5): 610-617.   DOI: 10.7518/hxkq.2022.05.016
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Quantitative grinding of abutment teeth is needed in crown and bridge restoration. Accurate quantitative preparation of teeth is one of the goals of minimally invasive restoration. In this paper, a case of congenital loss of upper and lower incisors was reported. Guided by the target restoration space (TRS), a personalized digital guide plate for tooth preparation was built to assist precise tooth preparation after the multidisciplinary combination therapy of orthodontic and periodontal teeth. Finally, the fixed bridge was prepared to meet the integrity, beauty, and function of the maxillary for the patient. In this case, the results suggest that the digital guide plate built under the guidance of TRS can be used to improve the accuracy of dental preparation.

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Evaluation of root-canal isthmus debridement efficacy of 3 kinds of activated irrigation technique
Cong Xinyu, Xue Ming.
West China Journal of Stomatology    2022, 40 (5): 554-559.   DOI: 10.7518/hxkq.2022.05.008
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Objective This study aimed to compare the capabilities of sonic, ultrasonic, and laser-activated irrigation for debris removal in the root canal isthmus. Methods A total of 32 human maxillary first premolars with root canal isthmus were prepared by Reciproc Blue, and were randomly divided into four groups (n=8, each group). The groups were subsequently subjected to different regimens as follows: the conventional syringe group (control group) was irrigated by No.27 side opening syringe, the sonic group with EDDY connected pneumatic motor, the ultrasonic group with IRRI Safe connected to a ultrasonic P5 handle, and the laser group with Er:YAG laser device connected to a 9 mm fiber tip for 20 s in each root canal. The first and last four samples in each group were irrigated for 80 and 120 s, respectively. All samples were fixed, decalcified, embedded, sectioned, and stained with hematoxylin-eosin. Image J software was used for measurement analysis of the isthmus and canal debridement efficacy, and SPSS 25.0 was utilized for statistical analysis of all data. Results The isthmus debridement efficacy of conventional syringe irrigation, sonic, ultrasonic, and laser groups after 80 s irrigation were 30.91%±3.14%, 52.22%±0.31%, 83.77%±5.64%, and 77.97%±7.97%, respectively. The isthmus debridement efficacy of the three experimental groups were better than the conventional syringe irrigation group (P<0.05). The isthmus debridement efficacies of ultrasonic and laser groups after 80 s were better than that of the sonic group (P<0.01, P<0.05). However, no significant difference was observed between the ultrasonic and laser groups. The isthmus debridement efficacy of conventional syringe irrigation, sonic, ultrasonic, and laser groups after 120 s were 75.72%±2.38%, 85.66%±4.42%, 88.07%±4.09%, and 89.12%±3.63%, respectively. The isthmus debridement efficacies of the three experimental groups were better than that of the conventional syringe irrigation group (P<0.05), but no significant difference was observed among the groups (P>0.05). The root canal debridement efficacy among the four groups also exhibited no significant difference (P>0.05). The debridement efficacies of the root canal and isthmus after 120 s irrigation were better than those after 80 s irrigation (P<0.01, P<0.001). Conclusion Ultrasonic, sonic, and laser-activated irrigation have better results in removing debris from the isthmus than conventional syringe irrigation. The isthmus debridement efficacy of sonic- and laser-activated irrigation are slightly better than that of ultrasonic activated irrigation. The debridement efficacies of 120 s irrigation are better than those of 80 s irrigaion.

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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.

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Effect of growth differentiation factor 11 on the steatosis of condylar chondrocytes in temporomandibular joint osteoarthritic mice
Wang Ruoxin, Liu Qian, He Feng, Zhang Mian, Wang Helin
West China Journal of Stomatology    2022, 40 (1): 14-21.   DOI: 10.7518/hxkq.2022.01.003
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Objective

To observe the effect of growth differentiation factor 11 (GDF11) on the steatosis of condylar chondrocytes in temporomandibular joint (TMJ) osteoarthritic mice.

Methods

Six-week-old female C57 mice were stimulated with unilateral anterior crossbite (UAC) and locally injected with GDF11. TMJ sections were stained with safranin O, and GDF11 and Adiponectin in the TMJ cartilage were detected by immunohistochemical staining. GDF11, Adiponectin, type Ⅱ collagen (Col-Ⅱ), Aggrecan, type Ⅰ collagen (Col-Ⅰ), fatty acid-binding protein 4 (FABP4), and Perilipin 1 mRNA were detected by real-time polymerase chain reaction (real-time PCR).

Results

The thickness and safranin O-positive area of TMJ cartilage in the UAC groups, as well as the mRNA expression of Col-Ⅱ and aggrecan, significantly decreased. The ratio of Adiponectin-positive cells significantly increased. The mRNA expression levels of Col-Ⅰ, Adiponectin, FABP4, and Perilipin 1 significantly increased. The TMJ cartilage of the GDF11 injection groups significantly thickened, and the safranin O-positive area significantly increased. The mRNA expression of Col-Ⅱ and Aggrecan significantly increased. The ratio of Adiponectin-positive cells significantly decreased. The mRNA expression levels of Col-I, Adiponectin, FABP4, and Perilipin 1 significantly decreased.

Conclusion

Extensive steatosis of chondrocytes and decreased expression of GDF11 in the degenerated cartilage of TMJ osteoarthritis are induced by UAC stimulation. Supplementation of exogenous GDF11 can effectively inhibit the steatosis of chondrocytes.

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Effects of grape seed proanthocyanidins on the expression of inflammatory mediators in gingival epithelial cells
Zhang Xiujuan, Wu Wei, Chen Xin, Fang Zhichun, Ye Jinxiang, Ou Xiaoyan.
West China Journal of Stomatology    2022, 40 (1): 39-44.   DOI: 10.7518/hxkq.2022.01.006
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Objective

This study aims to determine the effect of grape seed proanthocyanidin (GSP) pretreatment on lipopolysaccharide (LPS)-induced inflammation of human gingival epithelial cells (HGECs).

Methods

HGECs were cultivated with different concentrations of GSPs (0, 1, 5, 10, 20, 40, 60, 80, 100 μg·mL-1) for 6, 12, 24, and 48 h. CCK-8 was used to detect the proliferation activity of HGECs. HGECs were treated with different concentrations of GSPs (0, 10, 20, and 40 μg·mL-1) for 24 h and then cultured with 1.0 μg·mL-1 LPS. Enzyme-linked immunosorbent assay (ELISA) was used to detect the expression levels of pro-inflammatory cytokine tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 and anti-inflammatory cytokines IL-4, IL-10, and transforming growth factor-β (TGF-β). Quantitative real-time polymerase chain reaction (QRT-PCR) was used to detect the mRNA expression levels of TNF-α, IL-1β, IL-6, IL-4, IL-10, and TGF-β.

Results

When the GSP concentration was 0-40 μg·mL-1, the cell proliferation had no significant difference. When the action time reached 24 h, the cell proliferation was the highest. The results of ELISA and QRT-PCR showed that 10, 20, and 40 μg·mL-1 GSPS decreased the expression levels of TNF-α, IL-1β, and IL-6 (P<0.05) and increased the expression levels of IL-4, IL-10, and TGF-β compared with 0 μg·mL-1 GSPS (P<0.05).

Conclusion

GSPS (0-40 μg·mL-1) has no significant effect on the proliferation activity of HGECs. Pretreatment with GSPS can inhibit the expression of pro-inflammatory factors and enhance the expression of anti-inflammatory factors. Hence, GSPS has a certain preventive effect on the resistance of HGECs to the stimulation of endotoxin.

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Study on the inhibitory effect of selective estrogen receptor modulators on Streptococcus mutans
Liao Shengnan, Weitong Lü, Tang Quan, Ma Yuwen, Liu Lijia, Wang Liang, Peng Xian
West China Journal of Stomatology    2022, 40 (2): 218-224.   DOI: 10.7518/hxkq.2022.02.014
Abstract287)   HTML27)    PDF(pc) (1203KB)(118)       Save
Objective

To screen small-molecule antibacterial drugs and investigate the antibacterial effect and mechanism of selective estrogen receptor modulators (SERMs) against Streptococcus mutans (S.mutans).

Methods

The minimum inhibitory concentration of 426 Food and Drug Administration (FDA)-approved small-molecule drugs against S. mutans was determined using the microdilution method, and the target of SERMs acting on S. mutans was explored by employing a random transposon mutant library.

Results

Among the 426 FDA-approved SERMs, toremiphene, tamoxifen, clomiphene, and raloxifene exhibited excellent antibacterial effects against S.mutans. Results of mutant library screening showed that the two mutant strains were resistant to clomiphene. The gene sequence of the resistant strains showed that the transposon insertion sites were located in the genes of smu_546 and smu_874.

Conclusion

SERMs, such as toremifene, tamoxifen, clomiphene, and raloxifene, exerted obvious antibacterial effects on S. mutans, and their targets may be proteins expressed by smu_546 and smu_874 gene.

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Translation and validation of the Chinese version of the Child Perceptions Questionnaire for children aged 8-10 years
Zeng Xinyi, Cheng Bin, Zhang Lin, Guo Yuxuan, Li Yiling, Zou Jing, Wang Yan.
West China Journal of Stomatology    2022, 40 (1): 75-79.   DOI: 10.7518/hxkq.2022.01.011
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Objective

This study aimed to establish a Chinese version of the Child Perceptions Questionnaire for children aged 8-10 years (CPQ8-10) and evaluate its reliability and validity for a comprehensive and reliable assessment of oral health-related quality of life in children.

Methods

The Chinese CPQ8-10 was formed through translation, reverse translation, and cross-cultural adaption according to international standard procedures. It was used to evaluate the children's oral health-related quality of life to assess the reliability and validity of the scale.

Results

A total of 446 children received the survey, and 405 valid questionnaires were obtained. Cronbach's a for the full scale was 0.87, and the intraclass correlation coefficient for the total scale was 0.88. The CPQ8-10 score was significantly correlated with the score of two global questions (P<0.01). The dental caries group had the highest score of the full scale, followed by the malocclusion group; the healthy group had the lowest score (P<0.01).

Conclusion

The Chinese version of CPQ8-10 demonstrates great reliability and validity and provides a theoretical basis for its application in Chinese children aged 8-10 years.

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Effect of inward rectifier potassium 2.1 channel on the osteogenic differentiation of human dental follicle cells and its mechanism
Zhang Peng, Zuo Dongchuan, Mou Siyu, Zhong Yutong, Yuan Xiaoping, Zeng Jin
West China Journal of Stomatology    2022, 40 (2): 139-147.   DOI: 10.7518/hxkq.2022.02.003
Abstract269)   HTML38)    PDF(pc) (4528KB)(85)       Save
Objective

This study aims to explore the effect of inward rectifier potassium (Kir) 2.1 channel on the osteogenic differentiation of human dental follicle cells (hDFCs) and its mechanism.

Methods

hDFCs were isolated and cultured, and their source was verified by flow cytometry. Osteogenic differentiation ability of hDFCs was evaluated by osteogenic induction. Reverse-transcription polymerase chain reaction (RT-PCR) was performed to detect the gene expression of Kir2.1 gene (KCNJ2) in hDFCs. Real-time quantitative PCR (RT-qPCR) was performed to detect the expression of the Kir2.1 gene (KCNJ2) in hDFCs before and after osteogenic induction. Patch clamp technique was conducted to record the membrane potential changes of hDFCs before and after osteogenic induction. Moreover, the effect on the osteogenic differentiation of hDFCs was confirmed by increasing the concentration of extracellular potassium ions (50 mmol·L-1). Kir2.1 channel blockers cesium chloride (CsCl) and C19H20CINO (ML133) were applied to determine the effect of the Kir2.1 potassium channel on the osteogenic differentiation of hDFCs. At the same time, RT-qPCR was used to observe the expression changes of osteogenic differentiation related genes Runx related transcription factor 2 (Runx2) and osteocalcin (OCN) before and after the two intervention measures. Calcium imaging was performed to observe the effect of membrane potential hyperpolarization caused by decreased extracellular potassium level (2 mmol·L-1) on intracellular calcium concentration.

Results

RT-PCR results showed that hDFCs expressed the Kir2.1 channel gene (KCNJ2). The RT-qPCR results showed that the KCNJ2 gene expression in hDFCs was upregulated 7 days after osteogenic induction. The patch clamp results showed that the membrane potential of hDFCs hyperpolarized to (-47±5.2) mV from (-12±3.2) mV. Alizarin red and alkaline phosphatase staining results showed that increasing the concentration of the extracellular potassium or blocking the function of the Kir2.1 channel significantly inhibited the osteogenic mineralization ability of hDFCs. The membrane potential hyperpolarization increased the intracellular calcium concentration in hDFCs.

Conclusion

Membrane potential hyperpolarization mediated by the Kir2.1 channel plays an important role in the osteogenic differentiation of hDFCs.

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