Fused teeth are usually formed by the partial or complete fusion of two normal tooth germs during the development process and belong to dental developmental abnormalities. Fused teeth are relatively rare clinically, and those occurring in the posterior tooth area are even rarer. This article reports a case of fused teeth between the first permanent molar and the second permanent molar in the right mandible. This fused tooth had a complex root canal anatomical structure (seven root canals). The number and location of the root canals were analyzed by cone beam computed tomography, and root canal treatment was successfully completed with the assistance of microscope.
Humans ; Molar/diagnostic imaging* ; Mandible ; Dental Pulp Cavity/abnormalities* ; Cone-Beam Computed Tomography ; Root Canal Therapy/methods* ; Fused Teeth/surgery*

Dental trauma is one of the relatively common emergencies in clinical dental practice, with a high incidence rate, and the maxillary central incisors are the most frequently affected. This article reports a case of a 17-year-old female patient who suffered traumatic complete avulsion of teeth 11 and 21, with tooth 21 lost after avulsion. The prognosis for replantation was poor due to the absence of the buccal alveolar bone wall of tooth 11. Therefore, tooth 11 was treated with extracorporeal root canal therapy and then replanted into the alveolar socket of tooth 21, which had better conditions, followed by elastic splint fixation. After 20 months of follow-up observation, the affected tooth maintained a stable functional position, with no periapical inflammation or ankylosis observed. Subsequently, delayed implant restoration at the site of tooth 11 was performed, ultimately achieving a favorable treatment outcome. This case may provide new insights and references for future clinical practices in tooth replantation.
Humans ; Female ; Tooth Replantation/methods* ; Incisor/injuries* ; Adolescent ; Tooth Avulsion/therapy* ; Maxilla ; Root Canal Therapy

Digital guided therapy (DGT) has been advocated as a contemporary computer-aided technique for treating endodontic diseases in recent decades. The concept of DGT for endodontic diseases is categorized into static guided endodontics (SGE), necessitating a meticulously designed template, and dynamic guided endodontics (DGE), which utilizes an optical triangulation tracking system. Based on cone-beam computed tomography (CBCT) images superimposed with or without oral scan (OS) data, a virtual template is crafted through software and subsequently translated into a 3-dimensional (3D) printing for SGE, while the system guides the drilling path with a real-time navigation in DGE. DGT was reported to resolve a series of challenging endodontic cases, including teeth with pulp obliteration, teeth with anatomical abnormalities, teeth requiring retreatment, posterior teeth needing endodontic microsurgery, and tooth autotransplantation. Case reports and basic researches all demonstrate that DGT stand as a precise, time-saving, and minimally invasive approach in contrast to conventional freehand method. This expert consensus mainly introduces the case selection, general workflow, evaluation, and impact factor of DGT, which could provide an alternative working strategy in endodontic treatment.
Humans ; Consensus ; Endodontics/methods* ; Tooth ; Printing, Three-Dimensional ; Dental Care ; Cone-Beam Computed Tomography ; Root Canal Therapy

OBJECTIVE: To investigate the clinical application of cone-beam computed tomography (CBCT) among endodontic practitioners, and to analyze the indications and reasonability of CBCT in the diagnosis and treatment of pulpal and periapical diseases. METHODS: The clinical data were collected from patients who visited the Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology and underwent CBCT examination from January to December, 2021. The data with their complete clinical information (including clinical records, radiology request forms/reports, two-dimensional and three-dimensional imaging data) were included. Those who underwent CBCT examination for orthodontic or prosthodontics were excluded. The experience and training background of the endodontic specialists, the number of patients treated in the whole year, the objective and region of interest (ROI) of CBCT examination, technical parameters, such as machine type, field of view (FoV) and radiographic reports were collected and analyzed to evaluate the impact on diagnosis. Wilcoxon and Mann-Whitney tests were used to compare the distribution of CBCT ROI. Chi-squared test and pairwise comparison were used to compare the application of CBCT by endodontic specialists with different clinical experience (senior, middle and junior). RESULTS: In 2021, a total of 3 308 CBCT scans were prescribed by 61 endodontic specialists who treated 34 952 patients throughout the year. 3 218 patients (male ∶female about 1 ∶2) amounting for 10% of the patients treated in the whole year who received CBCT scans with an median age of 35 years (28, 49). Around 98% CBCT examinations were performed after clinical examination and two-dimensional periapical radiographs were taken. The FoV of CBCT scanning less than 10 cm×10 cm accounted for 96% of the total number of the images. Among the 3 308 CBCT scans, 83% of the ROI were in posterior teeth, with a higher number of anterior teeth (Z=-2.278, P < 0.05). Maxillary and mandibular first molars accounted for 35% of the examined teeth. The objectives of CBCT scanning included three aspects: clarifying clinical diagnosis, guiding surgical and non-surgical endodontic treatment (including management of endodontic complications), and outcome assessment, accounting for 1 111 (34%), 1 745 (54%), 311 (10%), respectively. and the others 2%. In the diagnosis process, CBCT was mainly used for the diagnosis of chronic periapical periodontitis, root fracture, root resorption and dental trauma. In the study, 353 CBCT were used in the diagnosis of root fracture, with a positive diagnosis rate of 35% (125/353). 846 CBCT used to reveal the anatomy of the root canal system, of which 297 cases were used to find missed/extra canals after treatment failure, and 58% (171/297) were used to confirm the missed/extra canals. In the management of complications or errors, CBCT was mainly used to assist the diagnosis of perforation and to locate the separated instruments. In the study, 311 CBCT scans were used for outcome assessment, including 240 cases related to non-surgical treatment and 71 cases related to surgical endodontic treatment for follow-up or presence of clinical symptoms, and persistent lesions on 2D films. Among the 61 endodontic specialists who used CBCT, 23 (45%) were with senior experience, 15 (30%) with middle experience, and 23 (25%) with junior experience. The proportion of senior or junior experience prescribing CBCT examination was 10%, higher than that of middle experience (8%, χ₁²=39.4, χ₂²=29.1, P < 0.001). The application rate of chief endodontists was 18%, which was higher than that of associate chief endodontists (9%, χ₁²=139.4, P < 0.001). 31% (1 109/3 308) cases of diagnosis or treatment plans were changed after CBCT was taken. CONCLUSION Use of CBCT in endodontic practice could provide more clinical information, which is helpful for diagnosis, accurate treatment and prognosis evaluation.
Humans ; Male ; Adult ; Prevalence ; Root Canal Therapy/methods* ; Cone-Beam Computed Tomography/methods* ; Tooth ; Imaging, Three-Dimensional

Pulp and periapical diseases are common and frequently occurring diseases of which diagnosis and treatment must be dealt with by the dental clinicians. The diagnostic techniques of these diseases include evaluation of pulp vitality, measurement of pulp blood circulation and analysis and judgment of root canal anatomy. With the continuous emergence of digital and imaging technologies, the correct application of these technologies in clinic will help clinicians improve their abilities in diagnosis and treatment of related diseases. The present article summarizes and reviews the progress of assistant technology for diagnosing dental pulp and periapical diseases in recent years and puts forward some suggestions for its application.
Humans ; Periapical Diseases/diagnostic imaging* ; Root Canal Therapy/methods*

Compared with cold lateral condensation and continuous wave of condensation which are classically used in clinical, newly emerging single-cone obturation technique is easy-to-operate as well as time-saving. Especially when combined with bioceramic root canal sealers of improved physicochemical and biological properties, single-cone obturation technique showed satisfactory short-term outcomes in clinical observations. However, difficulties still exist in avoiding the root canal overfilling and in operating the retreatment. Besides, the long-term effects of single-cone obturation with bioceramic sealers still remain unclear. This article makes an overview on the history and development of single-cone obturation ,and provides analysis of its pros and corns. Furthermore, we would also like to summarize its clinical application and look into its future improvements.
Epoxy Resins/chemistry* ; Gutta-Percha/chemistry* ; Retreatment ; Root Canal Filling Materials/therapeutic use* ; Root Canal Obturation/methods* ; Root Canal Therapy

The aim of this study was to investigate the cytotoxicity of modified nonequilibrium plasma with chlorhexidine digluconate (CHX) on human gingival fibroblasts (HGFs), and to evaluate the biosecurity of modified nonequilibrium plasma with 2% CHX as a new method of root canal treatment. Tissue samples taken from human gingiva were primarily cultured and passaged. Cells from passages 3-7 were used. HGFs were treated by modified nonequilibrium plasma with 2% CHX for 0 min (control group), 30 s, 1 min, 1.5 min, 3 min, 5 min, and 10 min, respectively, and then they were incubated for 0, 24, and 48 h. After that, cell counting kit-8 (CCK-8) assay was applied to analyze the cytotoxicity of modified nonequilibrium plasma with 2% CHX on HGFs. There was no significant difference between the 0 h group treated with the modified nonequilibrium plasma for 1 min and the control group (P>0.05). However, there were significant differences between all the other treated groups and the control group (P<0.05). When treated for 1.5 min or shorter, the cell viability was obviously increased; while treated for 3 min or longer, it was obviously reduced. Moreover, when successively cultured for 0, 24, and 48 h, cell viability was decreased at first and then increased in the 3-min-treated and 5-min-treated groups. The modified nonequilibrium plasma with 2% CHX was of no influence on cell viability in 1.5 min treatment, and it could be safely used on root canal treatment.
Adolescent ; Adult ; Anti-Infective Agents, Local ; adverse effects ; toxicity ; Cell Survival ; drug effects ; Cells, Cultured ; Chlorhexidine ; adverse effects ; analogs & derivatives ; toxicity ; Fibroblasts ; drug effects ; Gingiva ; cytology ; Humans ; Plasma ; chemistry ; Root Canal Therapy ; instrumentation ; methods

Mineral trioxide aggregate (MTA) is considered at the present time as the gold standard for root-end filling in endodontic surgery. However, this biocompatible material presents several drawbacks such as a long setting time and handling difficulties. The aim of this article is to present a new commercialized calcium silicate-based material named Biodentine with physical improved properties compared to MTA in a clinical application. Two endodontic microsurgeries were performed by using specific armamentarium (microsurgical instrumentation, ultrasonic tips) under high-power magnification with an operatory microscope. Biodentine was used as a root-end filling in order to seal the root canal system. The two cases were considered completely healed at 1 year and were followed for one more year. The 2-year follow-up consolidated the previous observation with absence of clinical symptoms and radiographic evidence of regeneration of the periapical tissues.
Calcium Compounds ; therapeutic use ; Female ; Follow-Up Studies ; Humans ; Microsurgery ; instrumentation ; Middle Aged ; Periapical Diseases ; therapy ; Periapical Tissue ; diagnostic imaging ; physiology ; Radiography, Bitewing ; Regeneration ; physiology ; Retrograde Obturation ; methods ; Root Canal Filling Materials ; therapeutic use ; Root Canal Preparation ; instrumentation ; Silicates ; therapeutic use ; Ultrasonic Surgical Procedures ; instrumentation ; Wound Healing ; physiology

Effective final irrigation regimen is an important step in order to achieve better disinfection and ensure residual antimicrobial effects after root canal preparation. The aim of this study was to compare the residual antimicrobial activity of 0.2% cetrimide, and 0.2% and 2% chlorhexidine in root canals infected with Enterococcus faecalis. Biofilms of E. faecalis were grown on uniradicular roots for 4 weeks. After root canal preparation, root canals were irrigated with 17% ethylenediaminetetraacetic acid (EDTA) to remove the smear layer. The roots were randomly divided into three experimental groups (n=26) according to the final irrigating solution: Group I, 5 mL 0.2% cetrimide; Group II, 5 mL 0.2% chlorhexidine; and Group III, 5 mL 2% chlorhexidine. Samples were collected for 50 days to denote the presence of bacterial growth. The proportion of ungrown specimens over 50 days was evaluated using the nonparametric Kaplan-Meier survival analysis. Differences among groups were tested using the log-rank test and the level of statistical significance was set at P<0.05. The highest survival value was found with 2% chlorhexidine, showing statistically significant differences from the other two groups. At 50 days, E. faecalis growth was detected in 69.23% specimens in Groups I and II, and in 34.61% specimens of Group III. There were no significant differences between 0.2% cetrimide and 0.2% chlorhexidine. Final irrigation with 2% chlorhexidine showed greater residual activity than 0.2% chlorhexidine and 0.2% cetrimide in root canals infected with E. faecalis.
Anti-Infective Agents, Local ; administration & dosage ; therapeutic use ; Bacterial Load ; drug effects ; Biofilms ; drug effects ; Cetrimonium Compounds ; therapeutic use ; Chlorhexidine ; administration & dosage ; therapeutic use ; Dental Pulp Cavity ; microbiology ; Edetic Acid ; therapeutic use ; Enterococcus faecalis ; drug effects ; Gram-Positive Bacterial Infections ; drug therapy ; Humans ; Microscopy, Electron, Scanning ; Root Canal Irrigants ; administration & dosage ; therapeutic use ; Root Canal Preparation ; methods ; Smear Layer ; Time Factors

In this study, we evaluate the influence of post surface pre-treatments on the bond strength of four different cements to glass fiber posts. Eighty extracted human maxillary central incisors and canines were endodontically treated and standardized post spaces were prepared. Four post pre-treatments were tested: (i) no pre-treatment (NS, control), (ii) sandblasting (SA), (iii) silanization (SI) and (iv) sandblasting followed by silanization (SS). Per pre-treatment, four dual-cure resin cements were used for luting posts: DMG LUXACORE Smartmix Dual, Multilink Automix, RelyX Unicem and Panavia F2.0. All the specimens were subjected to micro push-out test. Two-way analysis of variance and Tukey post hoc tests were performed (α=0.05) to analyze the data. Bond strength was significantly affected by the type of resin cement, and bond strengths of RelyX Unicem and Panavia F2.0 to the fiber posts were significantly higher than the other cement groups. Sandblasting significantly increased the bond strength of DMG group to the fiber posts.
Aluminum Oxide ; chemistry ; Composite Resins ; chemistry ; Curing Lights, Dental ; classification ; Cuspid ; pathology ; Dental Bonding ; Dental Etching ; methods ; Dental Materials ; chemistry ; Dental Stress Analysis ; instrumentation ; Glass ; chemistry ; Humans ; Incisor ; pathology ; Materials Testing ; Microscopy, Electron, Scanning ; Polymerization ; Post and Core Technique ; instrumentation ; Resin Cements ; chemistry ; Root Canal Preparation ; methods ; Self-Curing of Dental Resins ; methods ; Silanes ; chemistry ; Stress, Mechanical ; Surface Properties ; Tooth, Nonvital ; therapy