01 January 2022, Volume 49 Issue 1 Previous Issue   
Orginal Article
Periodontal considerations in prosthetic dentistry
Cao Zhengguo
Int J Stomatol. 2022, 49 (1):  1-11.  DOI: 10.7518/gjkq.2022001
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The interrelationship between periodontics and prosthetics has been widely discussed by dentists. A healthy and stable periodontal condition is a necessary prerequisite for the success and long-term stability of prosthetic therapy and should be paid close attention to before, during, and after prosthetic therapy. At the same time, soft and hard tissue defects, aesthetic problems, and tooth loss related to periodontal issue need to be solved by prosthetic therapy. Periodontal considerations in prosthetic dentistry are of great clinical significance. Therefore, this paper will discuss the periodontal preparation and health maintenance before, during, and after prosthetic treatment, the influence of prosthetic treatment on periodontal health, and the relationship between periodontics and implantology to provide basis for clinical work of dentists.

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Research progress on the biomedical applications of photosensitive hydrogels
Liang Yi,Pei Xibo,Wan Qianbing
Int J Stomatol. 2022, 49 (1):  12-18.  DOI: 10.7518/gjkq.2022015
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Photosensitive hydrogels are water swollen three-dimensional polymers, which are responsive to light. Photosensitive hydrogels have properties similar to natural extracellular matrix. They can be operated remotely without contact and spatiotemporally controlled with high precision by light stimulation. Accordingly, they are widely studied and applied in the fields of biological scaffold, drug delivery, three-dimensional cell culture and stomatology. This study reviews the applications of photosensitive hydrogels in biomedical fields based on domestic and foreign literature. Their potential for development and potential future challenges are also outlined.

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Research progress on various dental pulp regeneration scaffolds
Zhou Yi,Zhao Yuming
Int J Stomatol. 2022, 49 (1):  19-26.  DOI: 10.7518/gjkq.2022002
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Pulp regeneration is a new treatment approach for pulp inflammation or necrosis of young permanent teeth and induces apical foramen closure, root canal wall thickening, and root length increase. To improve the success rate of dental pulp regeneration, suitable scaffolds are fundamental to provide proper three-dimensional space and regulate stem cell differentiation, proliferation, and metabolism. At present, many studies have shown that a variety of scaffolds have potential for pulp regeneration. These scaffolds originate from biological extraction or artificial synthesis, and each has its own advantages. Biological extraction scaffolds mainly include blood clot, platelet rich plasma, platelet rich fibrin, polysaccharides, collagen, silk, acellular extracellular matrix, etc. Synthetic scaffolds mainly include polymers, bioceramics and composite scaffolds. In this review, we searched the literature on dental pulp regeneration in the past fifteen years and summarized the research progress on the performance and application prospects of above-mentioned various dental pulp regeneration scaffolds.

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MicroRNA profile of exosomes derived from dental pulp stromal cells under three-dimensional culture condition
Ai Xiaoqing,Dou Lei,Qiao Xin,Yang Deqin
Int J Stomatol. 2022, 49 (1):  27-36.  DOI: 10.7518/gjkq.2022026
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Objective This study aims to analyze and compare microRNA (miRNA) profiles in exosomes (Exo) derived from human dental pulp stromal cells (DPSCs) under two-dimensional (2D) and three-dimensional (3D) culture condition. Methods DPSC-Exo was extracted from 2D and 3D culture of DPSCs and identified by transmission electron microscopy, Western blot analysis, and nanoparticle tracking analysis (NTA). Differentially expressed miRNAs were screened by high-throughput sequencing for bioinformatics analysis and target gene prediction related to tissue regeneration and repair by using Dr.Tom system and TargetScan Website. Results 2D-DPSC-Exo and 3D-DPSC-Exo showed “saucer-like” double-layer membrane structure, expressed CD63 and CD9 positively and had diameter consistent with Exo characteristics. A total of 253 Exo-derived miRNAs were detected, among which 222 were in the 3D group and 99 were specifically expressed. Compared with the 2D culture, a significant difference of 60 [︱log2(3D/2D)︱≥1, Qvalue≤0.001]. Differentially expressed miRNAs were mainly involved in cellular process and binding. The Kyoto encyclopedia of genes and genomes (KEGG) pathway showed that these miRNAs were significantly enriched in metabolic pathways. Candidate target genes of miR-302 include fibroblast growth factor (FGF) 19 and epidermal growth factor receptor. Candidate target genes of miR-24-3p may play a role in tissue regeneration and repair, including neuronal differentiation (NEUROD) 2, neuroepithelial cell transforming 1, NEUROD1, neuronal regeneration-related protein, FGF11, FGF binding protein 3, FGF receptor 3, platelet-derived growth factor receptor (PDGFR) beta polypeptide, PDGFR alpha polypeptide, angiopoietin 4, and insulin-like growth factor binding protein 5. Conclusion Compared with 2D culture, 3D culture could regulate the expression of some miRNAs in DPSC-Exo. Upregulated miRNAs are mainly related to regeneration and repair, and 3D culture might be suitable to optimize the therapeutic potential of Exo.
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Data simulation optimization of root canal preparation sequence
Ji Xiao,Jing Fangqi,Li Ya,Xue Jing
Int J Stomatol. 2022, 49 (1):  37-47.  DOI: 10.7518/gjkq.2022027
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Objective This study aims to evaluate the effect of existing nickel-titanium files in root canal preparation and explore the best root canal preparation sequence.Methods Excel 2016 was used to derive the formula for calculating the surface area and volume of the file with a specific diameter and taper. Numerical simulation was performed with the volume and surface area growth rate of the root canal taken as the main index, combining with line chart and taper coordinate chart.Results Among 26 products included, vTaper had the lowest average volume growth rate with the recommended preparation sequence. The best root canal preparation sequence corresponding to 1 glide path and 3 shaping files, 2 glide path and 3 shaping files, 1 glide path and 4 shaping files, 2 glide path and 4 shaping files were as follows: 2002—2003—2004—2504—3004, 2002—1803—1804—2004—2504—3004, 2002—1703—1704—2004—2504—3004,and 2002—1503—1703—1704—2004—2504—3004, individually.Conclusion According to data simulation, vTaper system with #20 K-file is the best sequence among the incorporated nickel-titanium file systems. The mean and variance of the root canal volume/surface area growth rates of the four optimal sequences are significantly lower than most existing systems. Results will provide a basis for subsequent experiments and help improve the success rate of root canal treatment and reduce complications.
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Finite element analysis of pressure distribution on the upper surface of the hard palate with different nasal ventilation
Xie Wenting,Xing Yaqin,Cui Yangyang,Yan Jiayin,Zhang Linkun
Int J Stomatol. 2022, 49 (1):  48-54.  DOI: 10.7518/gjkq.2022010
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Objective This study aims to analyze the mechanism of the effect of mouth breathing on hard palate descent and malocclusion by measuring the pressure of the upper surface of the hard palate with different nasal ventilation.Methods The three-dimensional models of the upper airway and nasal cavity of the healthy volunteer were reconstruc-ted by using cone beam computed tomography data and finite element software. The boundary conditions and numerical simulations were set under different breathing patterns after repairing the cavities, smoothing the model, and meshing.Results The upper airway and nasal cavity models of the healthy volunteer were established. Moreover, the pressure distribution cloud maps of inspiratory and expiratory of nasal breathing at different cross-sections of the upper airway and those of different nasal ventilation were obtained. The pressure on the upper surface of the hard palate with different nasal ventilation was also calculated.Conclusion With the decrease of nasal ventilation, the pressure of inspiratory airflow on the upper surface of the hard palate increased gradually, whereas that of expiratory decreased gradually. Both were getting closer to atmospheric pressure. The pressure gradient in the nasal cavity of inspiratory and expiratory decreased gradually.
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Effect of photon-initiated photoacoustic streaming Er: YAG laser on the water loss of dentin and compressive strength of root
Zhang Shan,Shen Shuping,Zhang Fang,Yang Weidong
Int J Stomatol. 2022, 49 (1):  55-59.  DOI: 10.7518/gjkq.2022004
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Objective This work aims to investigate the effects of photon-activated photoacoustic flow (PIPS) Er: YAG laser on root compressive strength and the water loss of the root canal wall dentin.Methods A total of 120 healthy orthodontic subtraction teeth extracted from the Department of Oral and Maxillofacial Surgery from July 2018 to September 2018 were randomly assigned into the following four groups using the random number table method: group A (PIPS Er:YAG laser washing group), group B (syringe washing group), group C (ultrasonic wave washing group), and group D (control group, untreated). Differences in the water content of root canal wall dentin and compressive strength of root before and after treatment were observed.Results The water content of the dentin of upper, middle, and lower root canals increased in all groups, but no significant difference was observed (P>0.05). In the upper segment of root canal wall, the water content of groups A and C was lower than that of groups B and D (P<0.05). In particular, that of group A was lower than that of group C (P>0.05), and that of group B was lower than that of group D (P<0.05). In the middle segment of the root canal wall, the water content of group A was lower than that of groups B, C, and D (P<0.05). In particular, that of group A was lower than that of group C (P>0.05), and that of group B was lower than that of group D (P<0.05). In the lower segment of root canal wall, the water content of group A was lower than that of groups B, C, and D (P<0.05). In particular, that of group A was slightly lower than that of group C (P>0.05), and that of group B was lower than that of group D (P<0.05). All groups had no significant difference in compressive strength (P>0.05).Conclusion Er: YAG laser PIPS technology can remarkably reduce the water content of dentin in the root canal wall but not the compressive strength of the root. Hence, this method has a good clinical application prospect.
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Value research on differential diagnosis of pleomorphic adenomas and adenolymphoma by histogram analysis of ultrasound gray
Xia Feifei,Qin Wenjuan,Feng Jia,Zhou Xuyang,Sun Ercan,Li Changxue
Int J Stomatol. 2022, 49 (1):  60-65.  DOI: 10.7518/gjkq.2022011
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Objective To investigate the value of gray-scale histogram in the differential diagnosis of pleomorphic Adenoma and Adenolymphoma of parotid gland.Methods The preoperative ultrasound images of 18 patients with pleomorphic Adenoma (PA) , and 13 patients with Adenolymphoma (AL) were analyzed for imaging gray-scale histograms parameters (mean, variance, skewness, Kurtosis, 1st, 10th, 50th, 90th, 99th percentiles).The Receiver Operating Characteristic (ROC) curve was used to calculate the differential diagnostic efficiency of each parameter.Results The variance of PA group was higher than that of AL group, but the skewness and kurtosis were lower than that of AL group, and the difference was statistically significant (P<0.05). The value of mean, the 1st, 10th, 50th, 90th and 99th percentiles between the two group had no significant difference (P>0.05). The analysis of ROC curve showed that the Kurtosis was the most effective parameter for differential diagnosis. The AUC was 0.744 (P=0.022), the best critical value was 1.71, the sensitivity was 76.9%, the specificity was 61.1%, and the yoden index was 0.380. Besides, The AUC, optimal critical value, sensitivity, specificity and Yoden index of variance were 0.735 (P=0.028), 864.94, 72.2%, 76.9% and 0.491 respectively.Conclusion The ultrasonic gray histogram has a certain value in the differential diagnosis between PA and Al.
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Research progress on applied clinical anatomy of spinal accessory nerve
Wu Xiaofen,Sun Rui
Int J Stomatol. 2022, 49 (1):  66-72.  DOI: 10.7518/gjkq.2022021
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Learning the clinical anatomy of spinal accessory nerve and its relevant structures is extremely important during neck dissection. In recent years, research results of anatomical variations in spinal accessory nerve, internal jugular vein and cervical nerves have been constantly updated. Thus, spinal accessory nerve imaging and whether to reserve level Ⅱb and cervical nerves can contribute to significantly reducing postoperative complications, such as shoulder syndrome.

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Research progress on the treatment of postoperative scar of cleft lip
Wu Min,Shi Bing,Li Chenghao
Int J Stomatol. 2022, 49 (1):  73-78.  DOI: 10.7518/gjkq.2022012
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Scar is a natural product of the process of wound repair. The incision made during cleft lip surgery inevitably leads to scar formation. The scar of cleft lip is an important factor affecting the overall postoperative appearance of the person. More importantly, it affects the physical and mental health of patients. On the basis of the characteristics of cleft lip scar, this paper reviews the mechanism, prevention, treatment and different intervention methods for managing cleft lip scar. Moreover, this paper explores the clinical effects of postoperative scar treatment.

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Mechanical properties of monolithic zirconia crowns and its relationship with clinical application
Yang Guangmei,Wang Jian
Int J Stomatol. 2022, 49 (1):  79-84.  DOI: 10.7518/gjkq.2022013
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Many types of zirconia materials are available for monolithic zirconia crown restoration in clinic. Traditional monolithic zirconia crowns have advantageous mechanical properties, while transparent zirconia crowns have favourable aesthetics but poor mechanical properties. After selecting the material, the mechanical properties of monolithic zirconia crowns are affected by clinical operation and intraoral use. With a whole clinical perspective including design, fabrication, try-on, bonding and intraoral use, this review intends to summarise and discuss problems such as making clinical decisions with the mechanical properties of monolithic zirconia crowns and determining the effects of clinical procedure on the mechanical properties to provide reference for the clinical application and research of monolithic zirconia crowns.

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Research progress on the role of specialized pro-resolving mediators in periodontitis
Bai Huimin,Zhang Yuwei,Meng Shu,Liu Chengcheng
Int J Stomatol. 2022, 49 (1):  85-93.  DOI: 10.7518/gjkq.2022022
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Periodontitis is a chronic inflammatory disease of periodontal supporting tissues initiated by oral biofilm. Specialised pro-resolving mediators (SPMs) are mediators derived from polyunsaturated fatty acids, and they can actively regulate the resolution of inflammation, change microbial composition, reduce pain and promote tissue regeneration. SPMs may serve as auxiliary means for the prevention and treatment of periodontal diseases. This paper summarised the classification and mechanism of SPMs and reviewed the latest research progress on its role in periodontal tissue inflammation and repair. This study aims to provide ideas and reference for further study on the mechanisms of the development of periodontitis and enhance the prevention and treatment of periodontitis.

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Research progress on motivational interviewing in the management of patients with periodontal disease
Mu Xinyue,Liu Shutai
Int J Stomatol. 2022, 49 (1):  94-99.  DOI: 10.7518/gjkq.2022005
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The consequences of insufficient compliance are always the focus and challenge in the management of patients with chronic diseases. Traditional health education is one-way knowledge dissemination, and patients usually abandon compliance shortly after passively receiving verbal or written advice. Motivational interviewing based on cross-theoretical models shows good intervention effects on the health management and behavior change of patients with chronic diseases in different fields. This low-cost, low-intensity psychological intervention technique has been recently used for the health management of patients with periodontal disease. Foreign studies found that MI shows a lasting intervention effect on improving the compliance of patients with periodontal disease in oral hygiene maintenance, smoking cessation, and other health behaviors. This psychological satisfaction indicates good development prospects and social value. Domestic research on MI to improve compliance in patients with periodontal disease is still in its early stage and faces certain problems, such as the insufficient understanding of its theoretical framework and limitations in the specific implementation process. With continuous promotion in China, MI provides a new psychological intervention in dental environment.

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Research progress on two-dimensional and three-dimensional cephalometric automatic landmarking
Liu Lijia,Mao Jing,Long Huan,Pu Yalong,Wang Jun
Int J Stomatol. 2022, 49 (1):  100-108.  DOI: 10.7518/gjkq.2022006
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Cephalometry is an indispensable measurement of orthodontic and orthognathic diagnosis and treatment. With the development of computer-aided technology, automatic landmarking of cephalometry has been achieved in two-dimensional cephalometry with high precision, which greatly reduces the workload of operators. However, without geome-tric distortion, tissue overlap, and other defects, the cone beam computed tomography images can accurately locate the anatomical landmarks of cephalometric analysis. This analysis is helpful for the diagnosis and analysis of congenital or deve-lopmental craniomaxillofacial asymmetry. Nowadays, the automatic landmarking of three-dimensional cephalometry is an important research direction in the field of cephalometry. Based on the classification of different automatic fixed-point methods, this study reviews the progress of two- and three-dimensional cephalometric automatic landmarking. Furthermore, the study discusses the accuracy of different automatic landmarking methods and proposes future research directions.

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Research progress on the mechanism and efficacy of molar distalization with clear aligner technique
Li Junlin,Xiao Liwei
Int J Stomatol. 2022, 49 (1):  109-115.  DOI: 10.7518/gjkq.2022009
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As a novel orthodontic treatment technology, the clear aligner technique is favored by patients and dentists for its aesthetic, comfort and convenient features. After more than ten years of technical improvement and material update, the efficacy of clear aligner technique is gradually optimized. Through its special way of applying orthodontic force, in addition to the torque and the anchorage control of attachment and auxiliary devices,the molars distally move with nearly bodily movement, meanwhile avoiding the mandibular rotation and reducing anchorage loss of the anterior teeth. This article reviews the mechanism and efficacy of clear aligner technique in molar distalization treatment, and points out the deficiencies in current research and the limitations in clinical application, providing a reference for clinical application and technical improvement.

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Research progress on the osteoprotegerin/receptor activator of nuclear factor-κB/receptor activator of nuclear factor-κB ligand signaling pathway of tooth eruption
An Ning,Li Jiao,Mei Zhidan
Int J Stomatol. 2022, 49 (1):  116-120.  DOI: 10.7518/gjkq.2022007
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Tooth eruption is a series of complicated and orderly physiological processes controlled by the dental germ, the alveolar bone, multiple cytokines, and multiple signaling pathways. In the tooth eruption processes, the dental germ moves toward the occasion plane and through the alveolar bone and the oral mucosa, until it finally reaches its functional position, which depends on the presence of osteoclasts. Moreover, the osteoprotegerin/receptor activator of nuclear factor-κB/receptor activator of nuclear factor-κB ligand (OPG/RANK/RANKL) signal pathway manipulates the alveolar remo-deling by regulating the differentiation and maturation of osteoclasts. This process may certify that among the tooth, the alveolar could be absorbed normally. However, the exact mechanism underlying tooth eruption remains unclear. Hence, this review describes the recent research progress on the OPG/RANK/RANKL signaling pathway of tooth eruption.

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Advancement of immediate dentin sealing
Ding Jingyu,Tian Zilu,Wang Huimin,Zhu Xuanyan,Yang Yubin,Zhu Song
Int J Stomatol. 2022, 49 (1):  121-124.  DOI: 10.7518/gjkq.2022003
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Immediate dentin sealing is the application of dentin bonding agent to seal exposed dentin immediately after the tooth preparation phase. Compared with delayed dentin sealing, immediate dentin sealing protects the freshly cut dentin, improves bond strength, and decreases bacterial leakage and dentinal sensitivity. This article reviews the rationale, clinical procedure, and effect of immediate dentin sealing.

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