The plasma matrix is a kind of autologous blood conduct. It has been widely used in maxillofacial tissue regeneration, skin cosmetology and some other fields. Recently, to preserve the dental pulp as well as the teeth, pulp regeneration therapy and apical surgery have become increasingly important as well as the applications of bioactive materials. As a kind of autologous bioactive material, the plasma matrix has some natural advantages as it is easy to obtain and malleable. The plasma matrix can be used in the following cases: ①pulp revascularization of young permanent teeth with open apical foramina that cannot stimulate apical bleeding; ② apical barrier surgery with bone defects and large area perforation repair with bone defects or root sidewall repair surgery; ③ apical surgeries of teeth with large area of apical lesions, with or without periodontal diseases. The plasma matrix is a product derived from our blood, and there are no obvious contraindications for its use. Several systematic reviews have shown that the plasma matrix can effectively promote the regenerative repair of dental pulp in patients with periapical diseases. However, the applications of plasma matrix are different because its characteristics are affected by different preparation methods. In addition, there is still a lack of long-term clinical researches on the plasma matrix, and the histological evidences are difficult to obtain, so a large number of in vitro and in vivo experimental studies are still needed. This article will describe the applications of different kinds of plasma matrix for dental pulp regeneration and bone tissue regeneration in apical surgeries to provide references for clinicians in indication selection and prognosis evaluation.

Cone beam computed tomography (CBCT) has been widely used in various fields of dentistry. The diagnosis of root fractures, especially vertical root fractures (VRFs) with CBCT images, has been a research hotspot since then. Research on this area mainly includes the following five aspects: ① the diagnostic efficiency of CBCT images for root fractures; ② the influence of scanning parameters on the diagnostic accuracy of CBCT images in root fractures, such as scanning field of view, spatial resolution, tube current and tube voltage; ③ whether the application of image postprocessing techniques, especially metal artifact reduction (MAR), can improve the diagnostic accuracy of root fractures after root canal treatment and/or there is a post core in the root canal; ④ establishment and validation of clinical diagnosis model for vertical root fracture; and ⑤ application of artificial intelligence technology and contrast agent in root canals for the diagnosis of CBCT image in root fractures. Compared with periapical radiographs, CBCT images can improve the diagnostic accuracy of root fractures in nonendodontic treated teeth; however, for teeth that have undergone endodontic treatment, the diagnosis of VRF must be combined with clinical signs. Vertical bone resorption in the buccolingual (palatal) direction is a characteristic indicator of VRF. The width of the VRF is an important factor affecting the diagnostic accuracy, but the voxel size used in CBCT scanning is not a necessary factor affecting its diagnostic accuracy; the fracture direction does not affect the diagnostic accuracy of the VRF. Image postprocessing techniques, especially MAR, cannot improve the diagnostic accuracy of VRF and may also reduce the diagnostic efficiency, so they are not recommended for clinical application.

Endodontic microsurgery is a vital treatment modality for teeth with persistent periradicular pathoses that have not responded to nonsurgical retreatment. The principle is to determine the reason for failure, completely eliminate the infection and promote periapical healing. Within recent years, endodontic microsurgery has evolved to become standardized and presents with a high success rate. However, its outcome is still influenced by many factors, including anatomy, periodontal condition, crown-to-root ratio, occlusion, the type of periradicular lesion, and prosthesis. Moreover, endodontists always concentrate on “the apex”, paying little attention to the general preoperative evaluation, accurate diagnosis, and comprehensive treatment plan. This article reviews the latest literature on these issues and the clinical experience of our research group and discusses the correlation between endodontic microsurgery and other oral disciplines, including periodontology, prosthodontics, oral implantology, oral and maxillofacial surgery and orthodontics. The oral interdisciplinary assessment should be made with comprehensive consideration of the root canal system, periradicular lesion, adjacent anatomical relationships, periodontal condition, occlusion, and esthetic rehabilitation. Based on these findings, the continuity of treatment will be optimized, and the best treatment plan will be proposed to provide clinical strategies for the diagnosis and treatment of complex periradicular diseases.

Root fracture is a kind of dental trauma involving dentin, cementum, pulp tissue, periodontal membrane ligament and even the surrounding alveolar bone. It occurs frequently between the ages of 10-20, mostly in the area of the maxillary anterior teeth with high aesthetic requirements. The treatment goal for root fracture in permanent teeth is to maintain the physiological and functional integrity of the tooth as much as possible and to reduce the incidence of complications. Clinicians usually classify the affected teeth according to the position of the root fracture, including the apical, mid-root, cervical-mid-root and cervical segments, since it determines the treatment plan and the prognosis of the affected teeth. CBCT examination can avoid misdiagnosis and missed diagnosis of root fracture to the greatest extent. The sequential treatment plan of root fracture after permanent anterior tooth trauma includes initial emergency treatment, pulp vitality monitoring and complication management during follow-up. Emergency treatment mainly includes local anesthesia and repositioning, if displaced, the coronal segment of the tooth as soon as possible. Then, after checking its position radiographically, adjustment occlusion and flexible splinting for 4 weeks (4 months for cervical root fracture). The process of root fracture repair includes many tissues and is affected by many clinical factors. Timely and standardized treatment and close follow-up according to the Dental Trauma Guideline guarantee a good prognosis of root fracture. The closer the root fracture line is to the apex, the higher the survival rate is. In addition to the location of the root fracture line, the prognosis is affected by many other clinical factors, such as the displacement of the coronal fragment of the root fracture, the pathological state of the dental pulp, patient age, developmental stage of the root, timely and good replacement of the root fracture, splinting method, and the presence of other dental trauma complications. Pulp vitality should be monitored regularly, and root canal therapy of the coronal segment should be carried out only when infection of the pulp is established. This article reviews the classification, diagnosis, emergency treatment, sequential follow-up treatment, and prognostic assessment of root fracture trauma to provide suggestions for clinicians to manage root fracture trauma in permanent teeth.

Contemporary endodontic microsurgery has emerged as a significant treatment modality in the retention of teeth with persistent apical periodontitis. This article proposes the concept of the full-cycle clinical management of endodontic microsurgery based on the condition of the patient and tooth, attempting to develop a comprehensive strategy for the examination, treatment and follow-up to save natural teeth. Full-cycle clinical management included preoperative consideration of the general condition and surgical site and selection of cases for endodontic microsurgery; intraoperative application of techniques such as lasers, "bone window" technique and targeted endodontic microsurgery to make the surgical approaches more varied and the operation minimally invasive; postoperative outcome assessment according to the history, clinical and radiographic examination; and analysis of the short- and long-term outcomes.

Vital pulp therapy aims to maintain healthy pulp tissue as much as possible to improve the long-term survival of teeth. It has limited indications and uncertain curative effects. The pathological changes in inflamed pulp are the histological basis for the determination of treatment strategies and the treatment outcome; however, pulp sensitivity testing cannot reflect the actual histological status of the pulp. With the development of basic and clinical research on vital pulp therapy, the innovation of modern diagnostic and therapeutic technology and capping material, vital pulp therapy can be used as a treatment of teeth on which it was previously thought pulpectomy was necessary. Based on the evidence-based literature, this paper analyzes and summarizes the pathological changes of pulpitis and clinical research on the treatment of pulpitis. Vital pulp therapy can be a treatment for mature teeth with carious exposure and symptoms of irreversible pulpitis if comprehensive applications, including laser Doppler flowmetry, tissue oxygen monitoring, magnetic resonance imaging and microscopy, are used to determine the degree of pulp retention and if infection control and the use of biocompatible capping material are emphasized. In the future, it will be necessary to improve the success rate of vital pulp therapy for the treatment of pulpitis through research on the mechanism of pulp repair and regeneration, the precise diagnosis of pulpitis, and the development of pulp capping materials.

Root canal isthmus(RCI) is defined as a narrow, ribbon-shaped communication between two root canals that contains pulp or tissue derived from pulp. Any root that contains two or more root canals has the potential to contain an isthmus. The incidence of RCI from different tooth positions varies, with the highest RCI incidences usually found in the mesial root of the mandibular first molar and the mesiobuccal root of the maxillary first molar. The presence of RCI increases the difficulty of root canal therapy and introduces uncertainty regarding the prognosis for dental treatment. It is recommended to use CBCT and dental microscopy to identify teeth with suspected RCI in clinical practice. At the same time, for treatment of teeth with RCI, appropriate instruments should be selected, and enhanced root canal irrigation assisted by ultrasound should be considered to improve the success rate of root canal treatment and endodontic root-end surgery. The current technology still has some limitations regarding the cleaning and filling of RCI and additional research and development. Improvement of the corresponding technology and equipment is a current research hotspot and a future research direction.

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.

With the gradual maturity of laser technology, it has become widely considered a new method for disease treatment. Nd：YAG laser and Er：YAG laser are two representative solid-state lasers. These lasers are easy to use, comfortable and safe, and thus, they have recently become a research hotspot in dental treatment. Nd：YAG laser and Er：YAG laser have been used for the treatment of dentin hypersensitivity and dental caries, root canal therapy, pulp preservation and apical surgery. They are effective adjuvant methods for the treatment of dental pulp diseases and provide new avenues for clinical treatment. In this paper, the application of Nd：YAG laser and Er：YAG laser in the treatment of dental pulp disease is described to provide a reference for clinical treatment options.

Tooth defects due to dental caries, trauma, abrasion, etc., are extremely common and can be treated by direct or indirect restoration. Compared with resin directly filling the body, an inlay can better restore the occlusal contact relationship and the adjacent surface contact relationship and has good mechanical properties. In recent years, with the development of ceramic materials and bonding systems and the popularity of chairside CAD/CAM technology, the chairside CAD/CAM porcelain inlay restoration program has been well received by doctors and patients because of its accuracy, convenience, aesthetics, hardness and stability, and this program is widely used clinically. This review covers the research status of various aspects such as indications and contraindications for chairside CAD/CAM inlay restoration, pre-restoration preparation, tooth preparation, hole type, impression taking and design, porcelain block selection, bonding, polishing, postoperative doctor’s instructions, and common postoperative complications. It is expected to provide a reference for the clinical application of and research on chairside CAD/CAM inlay restoration technology.

Cracked tooth is a common type of tooth fracture with diverse symptoms, different treatment principles and unpredictable prognosis. The available remedies for immediate, intermediate and definitive managements include occlusal adjustment, orthodontic band, bonded composite resin, onlay, full crown and so on. For teeth with localized crack and vital pulp, bonded composite resin and onlay with cuspal coverage are also protective remedies besides traditional full-crown restoration. Once pulpal infection occurs, root canal therapy and full-crown restoration is indicated. Clinical determination should be made with comprehensive consideration of the location and depth of the crack, risk of extension and pulpal condition. This review will focus on the traits and prognosis of various therapy options, so as to provide evidence-based treatment planning of cracked tooth.

Dental operating microscope is recommended to complicated root canal therapy, for it could provide increased lighting and superior magnification, so that the survival rate of tooth is highly increased. More refined access of cavity preparation, canal cleaning, shaping and obturating are realized under microscope. This article combined literature reviews with the writers’ clinical experience, and it aims at helping clinicians to improve their ability to more accurately performance and minimally invasive endodontic procedures, such as locating hidden canals obstructed by calcifications, canals reduced in size, removing materials, reducing ledge formation, apical transportation, and repairing perforations.

Traditional resin-based composites have been placed in cavities by incremental layering technique. The shrinkage stress may result in microleakage, post-operative sensitivity which lead to the failed restorations. In 2009, bulk-fill resin-based composites were reported to have the capability to be placed and cured in 4-5 mm increments, because of the improved resin matrix, modified nano-hybrid fillers and new photo initiators. This group of materials can simplify operation in clinical application in addition to decrease shrinkage stress and polymerization shrinkage. The aim of this review is to summarize the classification and properties of bulk-fill resin-based composites and to discuss the development of these new materials in the future.

Minimally invasive root canal therapy should be defined as a discipline which adhere to a concept of preserving the healthy tooth structure as much as possible during all the root canal therapy procedure. In the past 15 years, the concept of minimally invasive has spread and developed fast throughout the diagnosis and treatment of endodontics, which made the root canal therapy (RCT) procedure safer, more accurate and efficient. Minimally invasive endodontics rely on the development of various kinds of therapeutic devices and materials, including the 3D image auxiliary equipment, operation microscope, the NiTi instrument systems and the disinfection and obturation material. Minimally invasive endodontics is a therapeutic concept of the modern root canal therapy which redefined the standard of what a successful RCT is.

Tissue engineering has been applied to induce pulp-dentin complex regeneration, and proposed the concept of regenerative endodontics. As a new subject in stomatology, regenerative endodontics promotes root development and pulp regeneration with the combination of dental stem cells, biomaterial scaffolds and growth factors. Clinically, pulp regenerative technique has been used to treat necrosis and periapical periodontitis of immature permanent teeth. Numerous case reports and studies have proved the possibility of pulp regeneration, and regenerative endodontics will become a potential new treatment alternative of dental pulp diseases for dental clinician. In the present paper, we will summarize and analyze the current process and prospective of regenerative endodontics.

Endodontic treatment failure is usually characterised by the presence of post-treatment apical periodontitis, which may be persistent, emergent or recurrent. Understanding the causes of endodontic treatment failure and making a correct diagnosis are of paramount importance for the proper management of this condition. In clinical practise, endodontic treatment failure is mainly related to the poor quality of root canal treatment (RCT), the nature of the disease and the concomitant disease of the tooth. This article focuses on the above three factors and discusses the indications and basics of the procedures for optimal clinical management of this condition.

During oral treatment, accidental foreign body ingestion not only caused the psychological and physical damage to patient, but in severe case may endanger the patient’s life. This paper focus on this accidental situation by systematic review of literature, in order to alarm the dentists in terms of medical security.

With the advent of dental operating microscope, periradicular microsurgery significantly improved success rate of traditional periradicular surgery, which includes periradiacular curettage, apicoectomy and retrograde filling. The present paper summarizes indication, apical sealing inspection, incision and flap design in anterior aesthetic region, and healing criteria for periradicular microsurgery.

Over the past ten years, with the progress of science and technology and improvement of equipment, the root canal treatment level has been promoted rapidly, and the root canal treatment effect has realized qualitative improvement. The 3 elements for the success of the root canal therapy which were the understanding of the root canal, sufficient preparation, close obturation were summarized and analyzed in this paper.