Table of Content

    01 July 2022, Volume 49 Issue 4 Previous Issue   
    Expert Forum
    Difficulty assessment of invisible orthodontic treatment based on treatment plan and tooth movement pattern
    Zhao Zhihe.
    Int J Stomatol. 2022, 49 (4):  373-379.  DOI: 10.7518/gjkq.2022082
    Abstract ( 707 )   HTML ( 156 )   PDF(pc) (885KB) ( 547 )   Save

    The establishment of principles for assessing the difficulty in bracketless invisible orthodontic treatment for malocclusion based on the treatment plan and tooth movement patterns has practical significance and social value for improving the level of invisible orthodontic treatment in China and for promoting the rational distribution of medical resources. Malocclusion is one of three major oral diseases. China has a large demand for orthodontic medical resources, which used to be dominated by traditional fixed orthodontic technology. However, with the economic and social development of China and the advancement of invisible orthodontic technology, the demand for invisible orthodontic treatment is increasing. A reasonable assessment of the difficulty of implementing invisible orthodontic treatment plans to assist in clinical treatment plan decisions and to implement orthodontic tiered medical services has become a clinical problem that must be urgently solved. The author summarizes the research progress and individual clinical experience about the difficulty in assessment of invisible treatment. On the basis of the material mechanics of clear aligners and the principle of clinician-led treatment planning, the present paper discusses the key factors of assessment difficulty from the sagittal, vertical, and horizontal directions in extracted cases and non-extracted cases, as well as other factors that affect the difficulty of invisible orthodontic treatment. The author hopes that this paper can guide the clinical diagnosis and treatment of invisible orthodontics in China, promote the establishment of scientific and standardized tiered treatment, attract more clinicians and researchers to participate in the innovation of invisible orthodontic technology, and promote both academic and clinical levels of invisible orthodontics in China.

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    Tooth Development
    Research progress on expression distribution and regulation mechanism of clock genes in tooth development
    Zhao Manzhu,Song Jinlin
    Int J Stomatol. 2022, 49 (4):  380-385.  DOI: 10.7518/gjkq.2022057
    Abstract ( 202 )   HTML ( 22 )   PDF(pc) (1758KB) ( 59 )   Save

    The emergence of chronobiology has brought the change from static thinking to dynamic thinking in life s-ciences. The effects and mechanism of clock genes in dentistry, especially those involved in tooth development, have been the focus of research. Dental hard tissue shows the characteristics of clock rhythm. The phenomenon of incremental growth lines in tooth (e.g., horizontal pattern of glaze column, Retzius and von Ebner lines) was the histologic evidence for this condition. However, the molecular mechanism of how clock genes participate in the regulation of periodic mine-ralization of dental hard tissues still requires elucidation and has long been one of the research focuses in this field. Recent studies have focused on the dynamic expression and regulation of clock genes in tooth morphogenesis, especially in dental hard tissue mineralization. This paper aims to review the current development in the studies of the expression distribution, role, and molecular mechanism of clock genes in tooth development.

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    Research progress on the etiology of primary failure of eruption
    Zha Yunchen,Zhang Jiajia,Kong Weidong.
    Int J Stomatol. 2022, 49 (4):  386-391.  DOI: 10.7518/gjkq.2022072
    Abstract ( 780 )   HTML ( 145 )   PDF(pc) (796KB) ( 652 )   Save

    Primary failure of eruption (PFE) is a rare condition that causes posterior open bite. No obvious local or systemic factors can be found in clinical examination, and PFE is caused by a disturbance in the eruption mechanism. In recent years, scholars have carried out many studies on the aetiology of PFE. This review describes the recent research pro-gress on the possible aetiology of PFE and its related hypotheses.

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    Oral Microbiology
    Research progress on the relationship between Streptococcus mutans and Candida albicans in caries
    Li Shanshan,Yang Fang
    Int J Stomatol. 2022, 49 (4):  392-396.  DOI: 10.7518/gjkq.2022039
    Abstract ( 242 )   HTML ( 26 )   PDF(pc) (756KB) ( 95 )   Save

    The interaction among oral microbes is crucial for the occurrence of oral diseases. Streptococcus mutans and Candida albicans are common pathogenic microorganisms of childhood caries. The two kinds of microorganisms can cooperate or antagonize each other to cause caries through extracellular enzymes, quorum sensing signaling molecules, and compound metabolism. In this paper, the caries-inducing mechanism and synergistic and inhibitory effects in biofilm and the newly developed mixed biofilm as antibacterial therapy were reviewed. From the perspective of biofilm, the relationship between the two microorganisms and the occurrence of caries and the methods to inhibit the biofilm activity were explained. This work provides a new perspective for the development of new treatment strategies for dental caries.

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    Research progress on the role of Porphyromonas gingivalis on promoting the development of Alzheimer ’ s disease
    Wang Guanru,Feng Qiang.
    Int J Stomatol. 2022, 49 (4):  397-403.  DOI: 10.7518/gjkq.2022074
    Abstract ( 528 )   HTML ( 83 )   PDF(pc) (1661KB) ( 340 )   Save

    Periodontitis is an oral disease with high incidence in middle-aged and elderly individuals. It is also closely related to the increased risk of Alzheimer ’ s disease. Recent studies suggest that Porphyromonas gingivalis (P. gingivalis), the main pathogen of periodontitis, may be one of the pathogenic factors for Alzheimer ’ s disease. The DNA or specific antibodies of P. gingivalis can be detected in the cerebrospinal fluid or serum of patients with Alzheimer ’ s disease. Animal experiments showed that P. gingivalis or its toxic factors, such as lipopolysaccharide, gingival protease and peptidyl arginine deiminase, could reduce the learning and memory ability of mice. P. gingivalis could interfere with the host immune function by releasing a variety of inflammatory mediators, which cause a series of immune inflammatory reactions and destroy the function of host nerve cells. This study systematically reviewed the recent progress of P. gingivalis in the aetiology of Alzheimer ’ s disease to lay a foundation for comprehensively understanding the pathogenesis of Alzheimer ’ s disease.

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    Original Articles
    Effect of Zn-doped bioactive glass nanoparticles on the mechanical properties of modified composite resin
    Wang Luming,Cao Xiao,Wu Linyue,Li Yuncong,Lei Bo,Niu Lin
    Int J Stomatol. 2022, 49 (4):  404-411.  DOI: 10.7518/gjkq.2022063
    Abstract ( 206 )   HTML ( 17 )   PDF(pc) (1560KB) ( 48 )   Save

    Objective This study aimed to develop a novel composite resin modified using Zn-doped bioactive glass nanoparticles (Zn@BGN) with biological activity and to investigate the effect of Zn@BGN on the mechanical properties of the modified composite resin. Methods Three types of Zn@BGN with different ratios of zinc-doping ratios were synthesized using the sol-gel template method via the catalysis of dodecylamine. The optimum doping ratio of zinc was explored by performing a biological activity test in vitro. Three modified composite resin experimental groups were prepared by adding Zn@BGN with mass fractions of 10%, 15%, and 20%, and an unmodified composite resin served as the control group. The mechanical properties, such as flexural strength (FS), diametral tensile strength (DTS), compressive strength, and Vickers hardness, of the samples were tested using a universal material testing machine and a microhardness tester. ResultsZn@BGN prepared using the sol-gel template method showed relatively regular spherical particles with a diameter of approximately 150 nm and good monodispersity. In addition, it showed a good biological activity with 1.6%. No significant difference in mechanical properties was found between the modified groups and the control group when the ratios of Zn@BGN incorporation were 10% and 15% (P>0.05). However, the FS and DTS were significantly lower in the modified group with 20% incorporation than in the control group (P<0.05). Conclusion Zn@BGN featuring uniform particle size, good monodispersity, and excellent biological activity can be prepared using the sol-gel template method. Zn@BGN exerts no harmful effect on the mechanical properties of the modified composite resin with 15% incorporation.

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    In vitro cytotoxicity of composite resin and compomer and effect on osteogenic differentiation of osteoblasts
    Zhang Jingyi,Li Danwei,Sun Yu,Lei Yayan,Liu Tao,Gong Yu
    Int J Stomatol. 2022, 49 (4):  412-419.  DOI: 10.7518/gjkq.2022068
    Abstract ( 195 )   HTML ( 22 )   PDF(pc) (3559KB) ( 64 )   Save

    Objective To explore a new method for repairing root defects by observing the osteoblast toxicity of composite resin and compomer, as well as their effects on osteogenic differentiation. Methods An experimental model of MC3T3-E1 was established for osteogenesis induction in vitro. Scanning electron microscope (SEM), cell counting kit-8 (CCK-8) detection, apoptosis and cell cycle detection, scratch experiment, alkaline phosphatase (ALP) activity detection, Alizarin red staining, and quantitative real-time polymerase chain reaction (qRT-PCR) were performed to compare the biological effects of the two materials on MC3T3-E1 cells. Results The MC3T3-E1 cells adhered to the two kinds of materials well. The composite resin extract showed slightly higher cytotoxicity to MC3T3-E1 but could promote cell migration and upregulate osteocalcin (OCN), osteopontin (OPN), runt-related transcription factor 2 (RUNX2), and collagen 1 (COL-1) mRNA expression. The compomer extract significantly inhibited the expression of osteogenic differentiation-related genes (P<0.05). Conclusion The slight cytotoxicity of the composite resin and compomer did not considerably affect the adhesion, growth, and normal differentiation of osteoblasts; thus, both materials have potential as bone replacement materials.

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    Incidence and related factors of middle mesial canals in mandibular first molars in Haikou
    Wu Wenzhi,Feng Da-xing,Chen Chuizhuang,Zhou Lijuan.
    Int J Stomatol. 2022, 49 (4):  420-425.  DOI: 10.7518/gjkq.2022020
    Abstract ( 513 )   HTML ( 51 )   PDF(pc) (1214KB) ( 189 )   Save

    Objective This study aimed to evaluate the incidence of middle mesial canals (MMCs) in mandibular first molar in Haikou and analyse the related factors. Methods The cone-beam computed tomography images of 1 964 mandibular first molars from 1 032 patients from January 2018 to December 2020 were retrospectively analysed. The morphological characteristics of mesial root canals were observed, and the incidence of MMCs was analysed. The age, sex, ethnicity, living environment, tooth position, distance between mesial buccal (MB) and mesial lingual (ML) root canal orifi-ces and existence of root canal isthmus (RCIs) were collected and recorded. Logistic regression analysis was performed on the related factors of MMCS. Results The incidence of MMCs in mandibular first molars was 22.3% in Haikou, and the additional type (3-2) was the most common type of MMCs, accounting for 63.8%. The incidence of RCIS was 50.5%. Multivariate logistic analysis showed that patients ≤40 years old (OR=2.667, 95%CI: 1.185-6.004), city residence (OR=1.456, 95%CI: 1.036-2.048), accompanied by RCIs (OR=3.808, 95%CI: 1.353-10.718), distance between MB-ML root canal orifices<3 mm (OR=3.374, 95%CI: 1.168-9.741) were independent risk factors for MMCs in mandibular first molars. Conclusion The incidence of MMCs in mandibular first molars in Haikou is relatively high, and the independent risk factors for MMCS were ≤40 years old, city residence, accompanied by RCIs and distance between MB-ML root canal orifices<3 mm.

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    Case Report
    Centric relation centered, facial esthetically and prosthetically driven digital workflow for edentulism implant rehabilitation: a clinical report
    Luo Qiyue,Liu Yeyu,Luo Yilin,Man Yi.
    Int J Stomatol. 2022, 49 (4):  426-431.  DOI: 10.7518/gjkq.2022075
    Abstract ( 256 )   HTML ( 24 )   PDF(pc) (2167KB) ( 99 )   Save

    This clinical report proposed a digital workflow for edentulism implant rehabilitation. 3-dimensional (3D)-printed individual trays and Gothic arch were used to obtain optimal fit with the patient’s soft tissue and centric relation recording. A 3D virtual patient was created with craniofacial hard tissue, intraoral soft tissue and extraoral facial profile after data superimposition of cone beam computed tomography (CBCT) volumetric data, scanned impression data and 3D extraoral facial scan. Tooth alignment was performed in correct centric relation and virtual smile design under the gui-dance of 3D virtual patient. All data could be collected in only two clinical appointments. Computer-guided implant surgery and computer-assisted design and computer-assisted manufacturing (CAD/CAM) interim prostheses were finished, allowing functional and esthetic rehabilitation in a predictable way.

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    Research progress on the genetic polymorphism of periodontitis
    Zhou Jiajia,Zhao Lei,Xu Xin
    Int J Stomatol. 2022, 49 (4):  432-440.  DOI: 10.7518/gjkq.2022055
    Abstract ( 246 )   HTML ( 32 )   PDF(pc) (787KB) ( 112 )   Save

    Periodontitis is a chronic infectious disease resulting from the complex interaction among microbial, genetic, and environmental factors. Genetic polymorphisms that affect host innate immune and regulate the structure of the microbial community have been implicated in the development and prognosis of periodontitis. Early studies on genetic susceptibility of periodontitis have focused on single-nucleotide polymorphisms of cytokines, chemokines, metabolic regulators, and proteins of innate and acquired immune responses associated with the development of periodontitis. With the completion of the Human Genome Project and the development of high-throughput sequencing technology, the genome-wide association study has become an effective strategy to study genetic variation in periodontitis. In addition, the post genome-wide association study applied new statistical methods to identify more genetic mechanisms of periodontitis. This review summarized the progress on the genetic susceptibility of periodontitis obtained from single-nucleotide polymorphism, genome-wide association, and post-genome-wide association studies to advance the knowledge on periodontal high-risk po-pulation precision management from the genetic polymorphism perspective.

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    Research progress on the relationship between vitamin D and medication-related osteonecrosis of the jaw
    Ji Xiao,Zhu Guiquan.
    Int J Stomatol. 2022, 49 (4):  441-447.  DOI: 10.7518/gjkq.2022081
    Abstract ( 472 )   HTML ( 90 )   PDF(pc) (750KB) ( 336 )   Save

    Medication-related osteonecrosis of the jaw (MRONJ) is a complication during or after the use of antiresorptive or antiangiogenic agents. It has many risk factors, but the specific pathogenesis and effective treatment remain unclear. Vitamin D is closely related to oral and systemic health, and recent research has focused on the relationship between vitamin D and MRONJ. Studies found that the occurrence of MRONJ may be related to vitamin D deficiency. The high-risk populations for MRONJ appear to overlap with those with inadequate vitamin D levels. Moreover, the mechanism of MRONJ may involve the interaction of related drugs and vitamin D deficiency in the damage process of calcium homeostasis and immune function. Therefore, vitamin D may be effective means of combating MRONJ. This article reviewed the recent research progress on the relationship between vitamin D and MRONJ.

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    Application of digital template in the extraction of embedded supernumerary tooth
    Pang Yu,Liu Xian,Wang Liao
    Int J Stomatol. 2022, 49 (4):  448-452.  DOI: 10.7518/gjkq.2022073
    Abstract ( 673 )   HTML ( 142 )   PDF(pc) (762KB) ( 594 )   Save

    Supernumerary teeth are extra teeth that need to be extracted. Achieving an efficient, safe and minimally invasive extraction with rapid and precise intraoperative location determination has been a clinical challenge in extracting embedded supernumerary teeth. Advances in imaging, digital technology and materials science could realise the accurate and minimally invasive extraction of such teeth. Based on the patient’s cone beam computed tomography image and computerised 3D modelling, the digital template acts as a ‘bridge’ that helps in the application of a surgical design to the real surgery directly, which could greatly shorten the surgery time, reduce the trauma and decrease the risk. The aim of this review was to summarise the functional realization of the template-guided extraction of embedded supernumerary teeth and the current application of digital guides and explore its future development trend.

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    Research progress on nasal airway among patients with cleft lip and palate
    Huang Yixuan,Shi Bing,Li Jingtao.
    Int J Stomatol. 2022, 49 (4):  453-461.  DOI: 10.7518/gjkq.2022062
    Abstract ( 172 )   HTML ( 19 )   PDF(pc) (837KB) ( 58 )   Save

    The congenital deformities of cleft lip and palate have significant effects on various physiological functions of the maxillofacial region including breathing. The team approach protocol mainly focuses on restoring appearance, speech, and occlusal function, instead of nasal breathing. In fact, there are significant structural anomalies in the nasal airway of patients with cleft lip and palate, which exert critical impacts on the patient ’ s quality of life. Therefore, on the basis of elucidating the anatomical anomalies associated with nasal breathing in patients with cleft lip and palate, this article reviews the influence of sequential treatment on nasal breathing, introduces commonly used assessment tools for nasal breathing, and provides references on how to better incorporate nasal breathing into the treatment planning for cleft lip and palate.

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    Research progress on the use of photothermal therapy to treat oral squamous cell carcinoma
    Zhao Zhuoping,Xin Pengfei,Gao Yang,Zhang Caifeng,Zhang Kuanshou,Liu Qingmei
    Int J Stomatol. 2022, 49 (4):  462-470.  DOI: 10.7518/gjkq.2022044
    Abstract ( 392 )   HTML ( 46 )   PDF(pc) (846KB) ( 204 )   Save

    At present, the most clinically applied and researched treatments for oral squamous cell carcinoma (OSCC) mainly include surgery, radiotherapy, chemotherapy, traditional hyperthermia, gene therapy, immunotherapy, and photodynamic therapy. However, the therapeutic effect of these treatments is limited and often accompanied by varying degrees of side effects. Photothermal therapy (PTT) is a novel type of treatment method that can selectively kill cancer cells through photothermal effect with high safety. The two elements of PTT are near infrared with good tissue penetration and photothermal conversion agents with modifiability and selectivity. By building nanocar-rier platforms, PTT can synergistically enhance the efficacy of other therapies and reduce their side effects. In this paper, the current treatment status of OSCC, the photothermal conversion principle of PTT, and its application in the treatment of OSCC were reviewed to provide a theoretical basis for the treatment of OSCC using PTT.

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    Research progress on Nod-like receptor protein 3 inflammasome in oral mucosal diseases
    Chen Siting,Zhong Xiong,Meng Wenxia.
    Int J Stomatol. 2022, 49 (4):  471-475.  DOI: 10.7518/gjkq.2022069
    Abstract ( 127 )   HTML ( 17 )   PDF(pc) (658KB) ( 24 )   Save

    Nod-like receptor protein 3 (NLRP3) inflammasome is a cytoplasmic macromolecular protein complex that recognizes bacteria, viruses, and other pathogens, as well as a variety of danger signals. It plays an important role in the immune system’s resistance to pathogen invasion. NLRP3 inflammasome also induces the release of pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18 by activating caspase-1, thereby causing an inflammatory response. Previous studies confirmed that NLRP3 inflammasome plays an important regulatory role in autoimmune and infectious diseases, such as rheumatoid arthritis and cardiovascular infections. However, the current research on NLRP3 inflammasome in oral mucosal diseases is still in its infancy. Combined with the related research at home and abroad in recent years, this paper briefly summarizes the research progress on the correlation between NLRP3 inflammasome and common oral mucosa diseases (such as oral lichen planus, recurrent aphthous ulcer, and autoimmune bullous diseases) and provides reference for the further study and application of NLRP3 inflammasome in oral mucosal diseases.

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    Research progress on the development of mesoporous calcium silicate nanoparticles in endodontics and repairing maxillofacial bone defects
    Zhang Xidan,Sun Jiyu,Fu Xinliang,Gan Xueqi.
    Int J Stomatol. 2022, 49 (4):  476-482.  DOI: 10.7518/gjkq.2022067
    Abstract ( 255 )   HTML ( 11 )   PDF(pc) (729KB) ( 73 )   Save

    Mesoporous calcium silicate nanoparticles (MCSNs), a novel bioactive material with a nanoscale size and an ordered mesoporous channel structure, possess excellent biocompatibility, bioactivity, antibacterial properties, and drug delivery characteristics. Besides, they can be modified by metal elements and improve the properties of biocomposites. Therefore, the development of MCSNs is currently a research focus in stomatology. MCSNs have antibacterial activity against a range of common oral pathogens. Moreover, they can cover the root canal wall, infiltrate the dentinal tubules, and induce cementum tissue regeneration; therefore, they have a potential in the endodontics field. Furthermore, MCSN scaffold showed excellent ability in osteogenesis and modification and thus could be potentially applied in oral and maxillofacial surgeries. This article reviews the biological properties and research progress of MCSNs in endodontics and their application in the repair of maxillofacial bone defects and provides preliminary experimental basis for further research on MCSNs.

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    Research progress on the stem cells from human exfoliated deciduous teeth in the regeneration and repair of oral tissue
    Li Pei,Lin Ling,Zhao Wei.
    Int J Stomatol. 2022, 49 (4):  483-488.  DOI: 10.7518/gjkq.2022045
    Abstract ( 280 )   HTML ( 24 )   PDF(pc) (722KB) ( 161 )   Save

    Stem cells from human exfoliated deciduous teeth (SHEDs) are a kind of dental stem cells extracted from the residual pulp of deciduous teeth. They are easy to obtain, store, and culture and have excellent self-renewal as well as multidirectional differentiation. SHEDs have obvious advantages compared with other mesenchymal stem cells. In recent studies, stem cell therapy using SHEDs has achieved good results in the regeneration and repair of a variety of oral tissues. This article describes the stemness maintenance and differentiation regulation of SHEDs and their advantages in stem cell therapy. Moreover, it reviews the research progress on SHEDs in pulp-dentin complex regeneration, periodontal tissue regeneration, bone regeneration, neuroprotection, and immune regulation.

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    Research progress on exosome composite scaffolds in oral tissue engineering
    Cai Chaoying,Chen Xuepeng,Hu Ji’an
    Int J Stomatol. 2022, 49 (4):  489-496.  DOI: 10.7518/gjkq.2022060
    Abstract ( 307 )   HTML ( 24 )   PDF(pc) (765KB) ( 87 )   Save

    Defects in various oral and maxillofacial tissues will seriously affect the appearance and function of patients, and effective repair of the defects is the focus of current clinical work. Oral tissue engineering achieves tissue regeneration and functional reconstruction through the application of scaffolds, growth factors and stem cells. The composite materials of stem cells and scaffolds are widely used in the regeneration of oral tissues due to their good regeneration performance. However, the stem cells have poor biocompatibility and low availability, inducing a bottleneck in clinical application. Compared with stem cells, exosomes have lower immunogenicity and higher yield, and are expected to replace stem cells in clinical application. Increasingly abundant scaffold materials can effectively protect and deliver exosomes to target tissues. At present, researches on the application of exosome composite scaffolds have covered the regeneration of jaw bone, articular cartilage, pulp and periodontal tissues. This article reviews the researches upon exosome composite scaffolds in the regeneration of oral and maxillofacial tissues.

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