With the continuous development of maxillary sinus floor elevation technology, the osteogenesis mechanism of maxillary sinus floor elevation has always been a concern of scholars. The membrane of the maxillary sinus is an indispensable physiological structure in the process of space osteogenesis under the sinus floor after elevation of the sinus floor. In recent years, the role of the maxillary sinus floor mucosa in sinus floor space osteogenesis has been a research hotspot. Recent studies have found that the maxillary sinus floor membrane plays a role as a natural biological barrier membrane in the process of sinus floor space osteogenesis after maxillary sinus floor elevation; in addition, it has the ability to undergo osteogenesis. It has also been found that maxillary sinus membrane stem cells (MSMSCs) derived from the maxillary sinus floor membrane have characteristics of mesenchymal stem cells, which can differentiate into osteoblasts and participate in sinus floor space osteogenesis after maxillary sinus floor elevation. New studies have also found that small RNAs such as microRNAs, long noncoding RNAs and circular RNAs can regulate the osteogenic differentiation of MSMSCs, which may be important biological targets for promoting osteogenesis in the sinus floor space. In this paper, the relationship between the maxillary sinus floor mucosa and bone formation after maxillary sinus floor elevation, the barrier and osteogenic function of the maxillary sinus floor mucosa, the sources of osteoblasts involved in osteogenesis of the sinus floor space, and the molecular regulatory mechanisms of stem cells derived from maxillary sinus mucosa will be elucidated step by step.
Objective To investigate the clinicopathological features and survival rate of oral squamous cell carcinoma patients in China. Methods The clinicopathological characteristics, stage, treatment modality, and 5-year disease-specific survival (DSS) rate of 1 915 OCSCC patients who received initial treatment at the Sun Yat-sen University Cancer Center from 1990 to 2013 were collected and analyzed. The clinicopathological characteristics, stage, treatment modality, and 5-year disease-specific survival (DSS) rate of OCSCC patients treated during the successive decades of 1990-1999, 2000-2009, and 2010-2013 were analyzed retrospectively to show the trends over time. Results The average age of all OCSCC patients who received initial treatment at this cancer center from 1990 to 2013 was 54.8 years (SD, 12.6 years). The sex ratio was approximately 2:1. The oral tongue was the site most prone for OCSCC, accounting for 63.6% of all cases. The proportions of early-stage (Ⅰ-Ⅱ) and advanced-stage (Ⅲ-Ⅳ) cases were approximate. Regarding the treatment modality, surgery-based treatment accounted for 80.4%. Survival analysis showed that the 5-year DSS rate of all cases was 57%. Survival decreased with age. The survival of females, nonsmokers, and nondrinkers was higher than that of males, smokers, and drinkers. The 5-year DSS rates of patients with squamous cell carcinoma of the lips, oral tongue, and other sites of the oral cavity were 81%, 63%, and 42%, respectively. The 5-year DSS rates of patients who received surgery-based treatment and nonsurgical treatment were 66% and 19%, respectively. The analysis of trends over time showed that in the period of 1990-1999 and 2010-2013, the age and sex ratio were relatively stable. The proportion of patients with squamous cell carcinoma of the lips and oral tongue gradually decreased, while the proportion of those with squamous cell carcinoma of the other sites of the oral cavity gradually increased. The proportion of surgery-based treatment increased from 77.7% to 91.3%. The 5-year DSS rate gradually increased from 53% in 1990-1999 to 64% in 2010-2013. The 5-year DSS rate of female patients increased significantly from 55% to 78%. However, the 5-year DSS rate of male patients was relatively stable. The 5-year DSS rate of patients who received surgery-based treatment gradually increased from 62% to 69%. Conclusion The 5-year DSS rate has steadily improved for OCSCC patients at this cancer center from 1990-2013, especially in female patients. The 5-year DSS rate of patients with squamous cell carcinoma of the oral tongue has reached the rate in developed countries worldwide. The proportion and survival rate of patients who received surgery-based treatment gradually increased. The survival rate of patients with squamous cell carcinoma of the other sites of the oral cavity was significantly lower than that of patients with squamous cell carcinoma of the lips and oral tongue, suggesting that more effort should be put into the treatment of patients with squamous cell carcinoma of the other sites of the oral cavity to improve the survival rate in the future.
Objective Comparision of the central location ability and clearance rate of ProTaper retreatment, Fengdu O-file and M3-RT three kinds of nickel-titanium instruments and hand stainless instruments K-file, H-file. Observe the form of the root canal wall. To provide experimental basis and reference for the clinical application of nickel-titanium instruments for root canal retreatment. Methods 40 simulated resin blocks with the same specification were randomly divided into four groups (n=10). Each group was separately prepared with hand stainless instruments K-file and H-file (group A1), ProTaper retreatment (group B1), Fengdu O-file (group C1), and M3-RT (group D1). Using scanner to obtain the pre- and post-operative images and overlapping the images through Photoshop. Measuring the root canal inner and outer wall resin removal with Image J, compared the central location ability of the four group. A total of 60 mandibular single canal premolars extracted due to orthodontics were collected. The teeth were randomly divided into four groups (n=15) after filling the root canal. Use hand stainless instruments K-file,H-file(group A2), ProTaper retreatment (group B2), Fengdu O-file(group C2) , M3-RT(group D2) to remove the filling materials. The roots were longitudinally sectioned, and the image of the root surface was photographed under the 10 × magnification microscope. The software was used to trace the area of the root canal wall and residual root filling, and the root filling clearance rate of each group was calculated. Two teeth were randomly selected in each group and observed under scanning electron microscope. Results Within 9 mm from the root tip hole, the central location ability of group B1, C1, D1 was better than that of group A1(P ＜ 0.05). At 4 mm from the root tip hole, group D1 has the best central location ability(P ＜ 0.05). There was no difference of the four instruments at a distance of 10 mm from the root tip hole（P ＞ 0.05）. There were various degree of filling material remained in the root canal after the four groups of instruments for retreatment canal preparation. There was no significant difference between group B2, C2, D2（P ＞ 0.05）, and both were higher than group A2(P ＜ 0.05). Scanning electron microscope observation results shown that the root canal wall prepared by group B2, C2, D2 was more smooth and continuous than group A2, and the residual filling material was less. Conclusion The central location ability of three kinds of nickel-titanium root canal retreatment instruments were significantly better than that of hand stainless instruments. ProTaper retreatment, Fengdu O-file and M3-RT three kinds of nickel-titanium root canal retreatment instruments showed good performance, the central location ability of M3-RT was slightly better. Nickel-titanium root canal retreatment instruments are more efficient than traditional hand stainless instruments in removing root fillings and the root canal wall after preparation is smoother and has good continuity.
Objectives The purposes of this study were to evaluate the long-term mechanical property, bacteria-killing ability, protein resistance and cytotoxicity of a novel antibacterial methyl methacrylate (MMA) resin. Methods The 2-methacryloyloxyethyl phosphorylcholine (MPC) has been added into the MMA used for making Hawley orthodontic retener according to the mass percentage 0% (control group), 1.5%, 2.25%, 3%, 4.5% and 6%. Specimens from the control group and MPC group were water-aged for 1 d, 90 d and 180 d, and then the universal material testing machine was used to investigate the long-term mechanical properties of the modified MMA specimens in the oral environment. The biofilm metabolic activity, colony-forming unit (CFU) and live/dead staining assay of the biofilms in the control group and MPC group in the oral environment were tested using the dental plaque biofilm model. The micro-bicinchoninic acid (BCA) method was used to determine the amount of protein adsorbed on the specimens. The MTT method was used to evaluate the cytotoxicity of the control group and MPC group. Results In the simulated oral environment, the addition of 0% to 3% MPC had no significant effect on the mechanical properties of the MMA specimen (P > 0.05). The control group and the modified MMA specimens with 3%MPC were statistically significant in time and the interaction effects between the two groups (P < 0.05). With increasing intervention time, the mechanical strength of both groups decreased, and the effect of time varied with grouping. The protein adsorption on the surface of the modified MMA material after adding 3% MPC decreased by approximately 80%, the metabolic activity of the biofilm decreased by approximately 50%, and biofilm CFU counts decreased by approximately 70% (P < 0.05) compared with the control. There was no statistically significant difference in time or interaction effects between the two groups. The amount of live green bacteria in the 3% MPC group decreased significantly after 1, 90, and 180 d of water aging. There was no significant difference in cytotoxicity between the control group and the MPC group (P > 0.05). Conclusions The addition of MPC into the MMA resin did not compromise the mechanical properties of the resin and exhibited long-lasting antibacterial and protein-repellent effects.
Objective The serum levels of iron, zinc, copper and vitamin D in severe early childhood caries (S-ECC) patients were investigated and analyzed to provide reference for primary prevention and diagnosis of S-ECC children. Methods A total of 184 children were enrolled in the Children Health Department of Xinjiang Medical University Health Management Center from June 2018 to June 2019. They were divided into the caries-free (CF) group (n=89) and S-ECC group (n=95). The contents of iron, zinc, copper and vitamin D were detected. Results The serum iron content of the CF group and S-ECC group was (8.36 ± 0.42) mmol/L and (8.13 ± 0.44) mmol/L, respectively, and the difference was statistically significant (t=3.50, P < 0.001); the serum content of zinc was (83.18 ± 7.28) μmol/L and (79.23 ± 6.38) μmol/L, respectively, and the difference was statistically significant (t=3.92, P < 0.001); the serum content of 25-hydroxyvitamin D was (86.72 ± 15.83) nmol/L and (77.75 ± 11.38) nmol/L, respectively, and the difference was statistically significant (t=4.42, P < 0.001). The serum copper content of CF group and S-ECC group was (20.18 ± 4.84) μmol/L and (19.49 ± 4.62) μmol/L, but the difference was not statistically significant (t=0.97, P=0.33). Conclusion The contents of iron, zinc and vitamin D in the serum of S-ECC patients are low, suggesting that iron, zinc and vitamin D supplementation should be emphasized in the prevention and treatment of S-ECC.
Objective To investigate the clinical characteristics, differential diagnosis and treatment of cheek mass caused by hyaluronic acid injection. Methods From March 2014 to December 2018, data from 5 patients with cheek masses caused by cosmetic fillings admitted to the First Hospital of Shanxi Medical University were collected, and their clinical, imaging, surgical and pathological features were summarized. Results All 5 patients were young females with a history of facial hyaluronic acid filling injection. Their clinical features were buccal and facial nodular masses, all of which were treated with surgery. The pathological report was fibrous adipose tissue with fat necrosis, and chronic inflammatory cell infiltration was observed in the interstitium. After the operation, the face shape was basically symmetrical, and there were no symptoms such as infection, limited mouth opening or facial paralysis. Conclusion The injection of facial hyaluronic acid may cause complications of nodular masses in the cheek, and intraoral resection is an effective treatment with good prognosis.
Objective To investigate the oral health behavior of urban and rural students in the 12~15 year age group in Guangdong Province, aiming to provide informational support for adolescent oral health care. Methods A multistage stratified sampling method with equal capacity and simple random sampling was applied to obtain representative samples. A total of 7 680 students aged 12 to 15 were selected from Guangdong Province, with 1 920 in each age group of 12, 13, 14 and 15 years; half were male and half were female, and half were from urban areas and half were from rural areas. According to the Fourth National Oral Health Epidemiology Questionnaire Survey Program, a standard questionnaire was designed to conduct on-the-spot investigations on sugar intake, brushing, dental floss usage, fluoride toothpaste usage. Results ① Eating before a meal and before bed: the proportion of sweet snacks, sweet drinks and sugary drinks consumed ≥2 times/day was higher in the rural group than in the urban group (P < 0.001), with only sugary drinks consumed significantly differently by age (P < 0.001). ② The rural group had a significantly lower proportion of brushing ≥ 2 times/day, flossing habits and fluoride toothpaste habits than the urban group (P < 0.001), whereas only fluoride toothpaste habits were significantly different across age groups (P < 0.001). Conclusions Among the students aged 12 to 15 in Guangdong Province, the rural group had a higher proportion of consuming desserts, sweet drinks and sweetened drinks. The proportion of brushing ≥ 2 times/day was lower, and the usage rate of floss and fluoride toothpaste was lower.
Objective To explore the cause and preventive measures of floor-of-mouth hematoma after dental implant placement. Methods The prevention of hematoma of the floor of the mouth in a case of lower anterior teeth implant placement was analyzed, and the literature was reviewed. Results Four mandibular vascular canals were found on the lingual side of the anterior mandible before dental surgery in the reported case. Two of them were quite thick (1.4 mm and 1.0 mm, respectively) and were located adjacent to the crest of the alveolar bone and superior to the mental spine. These two thick endosseous branches from the sublingual artery were dissected and ligated , and there was no obvious hematoma in the patients immediately after the operation and at the postoperative 3 d review. The results of the literature review show that the incidence of endosseous branches from the lingual vascular canal of the mandible is 90%-100%. The distribution of the vessels on the lingual side of the mandible is highly variable and adjacent to the lingual cortical plate. Accidental injury of the lingual cortical plate during implant surgery would probably lead to bleeding or hematoma on the floor of the mouth. Conclusion Mastering the anatomy of blood vessels on the floor of the mouth, elaboratively examining preoperative three-dimensional radiographic imaging, and cautiously exploring the lower jaw bone morphology after flap elevation are preventive measures to avoid damage to the arterial supply on the lingual side of the anterior lower jaw and to prevent complications of hematoma in the floor of the mouth.
Orthodontic resident training has a long history abroad. Its purpose is to teach general practitioners in dentistry about basic knowledge and operating standards and to lay a solid foundation for the normalization and standardization of techniques. Osaka Dental University, established in 1911, is one of the oldest dental higher education facilities in Japan and Asia. Its systematic orthodontic resident training program has specific characteristics, including a thorough foundation in basic training, sufficient practice time in clinical work, and an emphasis on both clinical thinking ability and technical detail mastery. Recently, orthodontic resident training programs in China have achieved significant progress in a short period. In this manuscript, we introduce the orthodontic training program of Osaka Dental University in terms of enrollment, training arrangements, orthodontic basic education and clinical training in order to offer a reference for the continuous improvement of the standardized training system for resident doctors of stomatology in China.
Objective To discuss the application of digital technology in the education of implant dentistry. Methods According to the teaching method that combines case-, problem- and team-based learning, a course on implant theory was carried out in a class of 20 students. Then, all the students in this class were divided into two groups to receive two clinical operation training courses. The first was the training of a free-hand implant, and the second was an implant operation under a digital template. The courses introduced digital technology into preclinical education and simulated implant training. After the two courses, students were organized to analyze the accuracy of the implant, the operation time and the experiences of these two courses. Through the comparison of students′ operations of free-hand and template implants, students could analyze their own faults and propose a method of improvement. The students scored the two classes. Results Through the two classes, all the students completed the implant operation under the guidance of a template and free-hand method and found their own problems and solutions. The combination of theory and practice deepened the students′ understanding of the teaching content. Finally, the classes were graded comprehensively by students, showing that the students′ satisfaction with the digital template class was higher than that with the free-hand class (P < 0.05). Conclusion The addition of a digital implant technology class significantly improved students′ comprehensive assessment, improved the teaching effect and was more acceptable to students in terms of gaining additional professional skills.
Sonodynamic therapy (SDT) is a cutting-edge method for the biological effects of ultrasound combined with sound-sensitive agents. In recent years, SDT has been a concern of experts and scholars in the oral field, and a series of experimental studies has been carried out. We will introduce the progress of SDT in the field of stomatology from three aspects: the therapeutic mechanism of SDT, the application of SDT in the oral field, and the current situation and future of SDT in the treatment of oral diseases. It is currently believed that singlet oxygen theory, cavitation effects, and induction of apoptosis are the main therapeutic mechanisms. The research of SDT on oral disease prevention mainly focuses on oral tumors (especially squamous cell carcinoma and osteosarcoma) and infectious diseases (such as periodontitis, maxillofacial infection, and oral mucosal disease). Although the current research is still in the experimental stage, with the continuous exploration of sonosensitizers and nanotechnology, SDT will provide great help for the clinical prevention and treatment of oral diseases in the future.
The colonization of microorganisms planted on the surface of teeth and restoration materials is the main cause of oral disease and treatment failure. How to improve the antibacterial properties of dental materials is a hot topic in dentistry. Nano-sized antibacterial materials have attracted much attention. Among them, metal and metal oxide nanoparticles are prominent due to their strong and broad-spectrum antibacterial activity. Thus, in recent years, many studies have used metal and metal oxide nanoparticles to develop antimicrobial dental materials for resin restoration, root canal therapy, orthodontic treatment, and implant surface and removable denture repair and have found that the antibacterial properties of nano-sized materials are significantly enhanced. However, the mechanical properties and esthetic properties of the modified materials are affected, so it is still necessary to explore appropriate modification methods. In addition, most of the experiments are carried out in vitro, which cannot accurately simulate the oral environment. Therefore, the antibacterial effect, cytotoxicity and immune response of these materials in vivo still need further research and exploration. This paper reviewed the potential antibacterial mechanisms and the safety of those nanoparticles and their applications in dentistry.
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