Posttreatment disease is a difficult clinical problem. Periradicular surgery is an important and effective method for cases that cannot be resolved by root canal therapy. In recent years, with the application of microscope for oral surgery and the development of microsurgical instruments, microsurgery in endodontics has reduced treatment trauma compared to traditional periradicular surgery and further improved the success rate of clinical treatment. However, as an invasive surgical method, the indications and timing of microsurgery in endodontics should be strictly defined for clinical applications. This paper reviews the literature on this important issue and discusses it with regard to the clinical experience of the author′s team. Explaining the effective root canal retreatment and good coronary closure are the primary considerations when posttreatment disease occurs. When root canal retreatment fails or cannot be completed after the initial treatment, the anatomical factors, lesion extent and periodontal lesion combination should be fully considered, and the microsurgery treatment strategy should be carefully formulated.
Objective To investigate the effects of X-ray irradiation on the proliferation and protein secretion in vitro in a cultured mouse osteoblast precursor cell line (MC3T3-E1) and to provide a basis for the prevention and treatment of radiation-induced bone injury.Methods Mouse osteoblast precursor cells (MC3T3-E1) in the logarithmic growth phase were divided into a 0 Gy control group, 2 Gy group, 4 Gy group and 8 Gy group according to the irradiation dose. The corresponding dose of X-rays was applied, and the changes in cell morphology after irradiation were observed. Cell proliferation was detected by the CCK-8 method, and alkaline phosphorus was detected at 7 days after irradiation. The alkaline phosphatase (ALP) activity and expression of secreted proteins were detected by high-throughput protein chip technology. The differential expression of proteins due to radiation damage was screened and verified by an ELISA.Results After irradiation, the soma and nucleus of MC3T3-E1 cells were enlarged. Compared to the control group, the cell proliferation rates of the 4 Gy and 8 Gy groups were significantly decreased starting at 3 days in culture (P < 0.05), and the cell proliferation decreased in a dose-dependent manner. After 7 days of culture, the ALP activity in the cells of each irradiated group was lower than that of the control group, and the difference was statistically significant (P < 0.05). Compared to the control group, 36 differentially expressed proteins were found in the supernatant after irradiation. Among them, the content of regulated upon activation, normal T cell expression and secreted factor (RANTES) was significantly increased in a dose-dependent manner.Conclusion A certain dose of irradiation can inhibit the proliferation of mouse osteoblast precursor cells (MC3T3-E1), and RANTES may be an important signaling factor induced by radiation damage.
Objective To compare the effects of four nickel-titanium root canal preparation instruments on removing fillings in severely curved root canals.Methods Forty single-bend resin root canals were selected to simulate curved root canals. A ProTaper Universal tool was used to prepare the canals to F2. Photographs were taken under a stereomicroscope. Photographs were then retaken after the canals were filled tightly using the hot gutta-percha continuous wave filling method. The canals were stored in a water bath at 37 ℃ and 100% humidity for 21 days. Forty processed root canal samples were randomly divided into four groups, with 10 in each group. ProTaper NEXT, Reciproc, Mtwo and Twisted File Adaptive (TFA) tools were used to remove fillings in the root canal. The time of the procedure was recorded, and photographs were taken again after the procedure was completed. The residual rate of filling materials, root canal displacement and procedure time were compared.Results The rates of remaining filling materials in the four groups were not significantly different (P > 0.05), and the amount of remaining filling material in the apical third was greater than in other parts of the canal (P < 0.05). At 1 mm (F=4.245, P=0.014), 2 mm (F=5.893, P=0.003), 3 mm (F=2.969, P=0.049), 6 mm (F=7.447, P=0.001) and 8 mm (F=3.567, P=0.027) from the apical point, the transportation of the Mtwo group was significantly greater than that in the other three groups. At the 4 mm from the apical point, the transportation of the Mtwo group was significantly greater than that in the ProTaper NEXT and TFA groups (P < 0.05). At the 5 mm from the apical point, the transportation of the Mtwo group was significantly greater than that of the TFA group (P < 0.05). The procedure times of the four experimental groups were not significantly different (F=0.925, P=0.44).Conclusion Four types of nickel-titanium root canal preparatory instruments can be used to remove fillings in severely curved root canals; the root canal deviations caused by the ProTaper NEXT, Reciproc and TFA instruments are different, but these tool can all be used in the treatment of curved root canals. None of the four instruments could completely remove the filling materials from the root canals, and the residual rate was highest for fillings in the apical third. Therefore, it is necessary to use other instruments or methods to further clean root canal fillings.
Objective To evaluate the mechanical properties and bacterial adhesion of the glass fiber-reinforced composite resin space maintainer.Methods The mechanical properties of the composite resin high-strength fiber （experimental group） and the band and loop type （control group） space maintainer were tested by universal material testing machine. The two types of space maintainer were placed on a plate with a strain of Streptococcus mutans. Scanning electron microscopy and viable cell counts were used to observe bacterial attachment.Results There was no significant difference in the maximum shear resistance between the experimental group（32.02 ± 4.315）N and the control group （33.35 ± 5.154）N space maintainer （P > 0.05）. Scanning electron microscope showed that streptococcal bacteria were attached to the surface of the two groups. The colony count quantity of the experimental group （10.02 ± 2.315） ×104 CFU/mL was decreased compared with that of the control group （14.35 ± 2.154） ×104 CFU/mL. The difference was statistically significant （P < 0.05）.Conclusion The composite resin high-strength fiber and the band and loop type space maintainer have comparable mechanical strength; however, the composite resin high-strength fiber bacteria adheres less than the band and loop type, and the self-cleaning function is relatively good.
Objective To observe the clinical effects of direct current iontophoresis (DCI) of triamcinolone acetonide (TA) on treatment of oral submucous fibrosis. Methods Fifty-one patients were randomly divided in group A (n=25), which underwent local submucous injection with TA (20 mg for each side) once a week for 8 weeks, and group B (n=26), which underwent local TA administration by DCI (20 mg for each side) for 8 weeks, follow-up was performed 12 weeks after treatment. The distances between the upper and lower central incisors were recorded. The visual analogue scale (VAS) was used to evaluate the pain caused by the two treatments. The Oral Health Impact Profile (OHIP)-14 was used to assess the entire effect of treatments. Results At 8 weeks of treatment, the mouth opening was increased by 3.25 ± 0.77 mm in group A and 3.76 ± 0.88 mm in group B (P＜ 0.05). At 20 weeks after treatment, the mouth opening was increased by 2.61 ± 0.62 mm in group A and 2.53 ± 0.52 mm in group B (P > 0.05). After the first treatment, the VAS score of group A was 7.88 ± 0.80, and the VAS score of group B was 2.47 ± 0.64, resulting in a statistically significant difference (P＜ 0.001). After the last treatment, the VAS score was 7.29 ± 0.53 in group A and 1.77 ± 0.48 in group B, resulting in a statistically significant difference (P＜ 0.001). The VAS scores of the two groups were decreased after treatment, and the difference between groups was statistically significant (P＜ 0.001). The OHIP-14 score of patients in group A before treatment was 31.44 ± 2.55, while that in group B was 32.04 ± 2.20 (P > 0.05). At 20 weeks after treatment, the score in group A was 13.52 ± 3.31 and that in group was 12.04 ± 2.84 (P > 0.05). The OHIP-14 scores of the two groups were significantly decreased before and after treatment, and the difference between groups was statistically significant (P＜ 0.001). Conclusion The results suggest that local TA administration by DCI might be a promising method for treatment in the early and middle disease periods in OSF patients.
Objective To explore the relationship between a short lingual frenulum and functional articulation disorders and to offer a reference for clinical diagnosis and treatment.Methods A total of 259 patients with functional articulation disorders who visited the West China Hospital of Stomatology from October 2016 to February 2019 were included. The lingual ligaments of patients were clinically examined under natural light and classified into 4 groups according to the distance between the ligament and tongue tip, the functional position of the tongue, and the shape of the tongue tip. Statistical analyses of speech error types and the correlation between functional articulation disorders and the lingual ligament were performed.Results Among all 259 patients, 220 patients had a normal lingual ligament, while only 39 patients had a short lingual ligament. The speech evaluation results of patients with a normal lingual ligament were as follows: no gas delivery 75, postconstructive tone 36, preconstructed tones 67, palatalized misarticulation 19, and consonant deletion 23. The speech evaluation results with a short lingual ligament were as follows: no gas delivery 12, postconstructive tone 5, preconstructed tones 13, palatalized misarticulation 4, and consonant deletion 5. No correlation was observed between functional articulation disorders and the lingual ligament (P=0.939).Conclusion No correlation was found between functional articulation disorders and the lingual ligament. Patients with functional articulation disorders should not be encouraged to undergo ankylotomy; however, speech training should be encouraged instead.
Objective To establish the first dento-maxillofacial deformity diagnosis and treatment database in China, provide reference for the clinical diagnosis and treatment of dento-maxillofacial deformity in China, and lay the data foundation for prospective and retrospective clinical research. Methods The database was designed by surgeons combined with clinical practice, and then the programmer is responsible for the programming of the database. Personal files were established for patients at the time of the initial diagnosis. In future diagnosis and treatment processes, patients’ medical information will be recorded, patients’ case data will be collected, the database system will be improved according to clinical feedback, and the adjustment and improvement phases will be continued. Results A database and statistical analysis system was successfully established for dental and maxillofacial deformities, the clinical diagnosis and treatment information of patients were recorded, and the effective management of clinical data of patients with dental and maxillofacial deformities was achieved. The database functions include data entry management, data query, statistical analysis, image management, information exporting, system management, database management and updating. Conclusion Patients with dental and maxillofacial deformities have a longer folow-up period and greater regularity of diagnosis and treatment, information of which suitable for the collection and management using this database. The application of this database will improve the management of diagnosis and treatment information for patients with dental and maxillofacial deformities, and the database has a statistical analysis function. It has provided assistance for clinical research, which is conducive to the cultivation of specialist talents and the treatment of dental and maxillofacial deformities.
Exosomes are bilayer lipid vesicles formed by a series of regulatory processes including endocytosis, fusion and efflux. Exosomes can be secreted by a variety of cells, including epithelial cells, mast cells, dendritic cells, T lymphocytes, and mesenchymal stem cells. Mesenchymal stem cells play an important role in tissue repair and regeneration, immune regulation, and tumor growth regulation and have a strong secretory capacity. The therapeutic mechanism of mesenchymal stem cells is related to their exosomes. Although this therapeutic mechanism is not fully understood, it has shown strong therapeutic potential. Dental pulp stem cells are undifferentiated mesenchymal stem cells that present in dental pulp tissue. Their use has many advantages, such as a lack of ethical controversy, easy access, and good safety. Recent studies have found that exosomes secreted by dental pulp stem cells have great potential for applications in pulp regeneration, anti-inflammation treatment, neurodegenerative diseases and tumors. This article reviews the synthesis, secretion, extraction and identification of exosomes, the biological functions of mesenchymal stem cell exosomes, and the related research on dental pulp stem cell exosomes and diseases to improve clinicians′ understanding of the mechanism of the occurrence and development of dental pulp stem cell exosomes in diseases. Treatment and further research of these diseases provide new ideas and targets.
Liposomes are microspheres that are similar to cell membranes. They have good sustained release, biocompatibility and targeting ability and can reduce the toxicity of encapsulated drugs. This article reviews the research progress of the use of liposomes in periodontal drug delivery systems and periodontal tissue engineering scaffolds. Liposomes have shown unique advantages and broad prospects in the field of periodontal drug delivery. Liposomes loaded with bioactive molecules and combined with periodontal tissue engineering scaffolds can improve the pharmacokinetics and local efficacy of these molecules. Modification of various extracellular matrix proteins on the surface of the scaffolds can promote the absorption of liposomes. Attachment of these proteins to the surface of the scaffold can reduce the requirement for bioactive molecules, improve the effective conversion rate and prolong the half-life of the scaffold in vivo. However, the development, clinical efficacy and safety evaluation of new liposomes still need to be further explored.
Dens invaginatus is a congenital tooth developmental malformation with substantial differences in anatomical morphology. Clinically it can be divided into malformed lingual fossa, root groove deformity, lingual cusp deformity and dens in dente. Most scholars believe that dens invaginatus is caused by the folding of the nipple during tooth development. Because of the complex anatomical shape, this condition often causes periodontal pulp joint lesions, which increases the difficulty of treatment. Therefore, this paper reviews the classification, morbidity, histopathology, clinical manifestations, imaging features and treatment methods of Oehlers crown indentation type III and malformation of the root groove to provide a reference and basis for clinical treatment. The literature review results show that the use of CBCT contributes to the diagnosis, treatment and prognosis of dens invaginatus. A personalized treatment plan should be developed based on different conditions by combining periodontal pulp therapy, pulp microsurgery, pulp revascularization, intentional replantation and other treatment techniques to preserve the teeth and improve the cure and preservation rates of teeth.
Myofibroblasts are fibroblasts with contractile function. As a contractile cell, myofibroblasts can regulate the function of normal organs in normal tissues. After tissue injury, myofibroblasts play an important role in mediating injury repair, but at the same time, myofibroblasts can also play an abnormal role in the formation of exocytic matrix during tissue fibrosis. This article reviews the relevant literature and discusses the role of myofibroblasts in orthodontic tooth movement. The literature review shows that mechanical stress and chemical stimulation can significantly promote the differentiation of precursor cells into myofibroblasts. TGF-β, Rho and Hippo signal transduction pathways play an important regulatory role in the differentiation process. Orthodontic tooth movement is a complex process of periodontal tissue remodeling, in which the periodontal ligament and gingiva are important periodontal soft tissues. In vivo studies have shown a large number of differentiated myofibroblasts in the tension-side periodontal ligament. Myofibroblasts participate in the remodeling of the periodontal ligament during orthodontic tooth movement and thus are closely related to orthodontic tooth movement.
Adenoid hypertrophy may cause abnormal breathing habits in children, which may cause abnormal development of soft and hard tissues of the maxillofacial region. Hypertrophic adenoids can cause the mandible to rotate backwards, forming a Class Ⅱ malocclusion. Recent studies have shown that such patients may progress to a Class Ⅲ malocclusion due to insufficient maxillary development. This article mainly discusses the mechanism, types and treatment of adenoidal hypertrophy and the formation of dental and maxillofacial deformities in children. The literature review results showed that adenoid hypertrophy causes abnormal mouth breathing habits, which causes patients to have a high arch, upper anterior labial tilt, mandibular retraction and other typical facial features; additionally, the buccal muscle strength is increased, resulting in upper and lower jaw arch stenosis, increasing the degree of dental and maxillofacial deformity in patients. However, some studies have found that hypertrophic adenoids are not directly related to dental and maxillofacial deformities. Such patients should be evaluated by a multidisciplinary team of orthodontists, otolaryngologists, and pediatricians to better provide effective treatment.
Implant denture repair technology has become a superior repair method for dentition defects and missing teeth. With the rapid increase in the number of implants placed, the rate of implant failure has also increased. The occurrence of disease around the implant is not caused by a single factor, and once it occurs, it will largely lead to implant restoration failure. To reduce the failure rate of implant restoration, clinicians are exploring the causes of diseases around implants. Among these causes, adhesive residue has been a focus of research in recent years. This article discusses common factors of adhesive residue and implants. The relevance of diseases in the tissue surrounding the implants and their treatment is reviewed. The literature review results indicate that factors that lead to adhesive residue include the unique biological composition around the implant, the edge position of the implant abutment, the type of adhesive, and the diameter of the implant, which eventually leads to the occurrence of diseases around the implant, resulting in implantation failure. Current mechanical debridement techniques and postoperative maintenance can achieve good therapeutic results.
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