Impacted teeth are a kind of complex malocclusion, and their incidence differs among different races, sexes and dental positions. The causes of impacted teeth include systemic factors and local factors, such as endocrine disorders, malnutrition, and acute and chronic infectious diseases. Local factors can cause abnormal tooth development or eruption during the process from tooth development to tooth eruption, such as damaged permanent tooth embryos caused by local inflammation or trauma, insufficient eruption space caused by premature loss of deciduous teeth, and eruption disorders caused by local lesions for example hyperplasia or odontoma. The clinical manifestation of impacted teeth is the absence of a permanent tooth in a normal position. We can use cone beam CT (CBCT) to locate the impacted teeth. Comprehensive orthodontic treatment includes surgical-assisted eruption, extraction of retained deciduous teeth or supernumerary teeth, removal of lesions such as odontomas and cysts, and expansion of the orthodontic space. When the dysfunctional local soft and hard tissues are removed during a surgical operation, the tooth still cannot sprout smoothly, and it needs to be assisted by orthodontic traction-guided eruption or extracted and autotransplantation. A clear diagnosis, evaluation of the difficulty of treatment and appropriate treatment are the keys to improving the success rate of treatment. In this paper, the epidemiology, etiology, diagnosis and corresponding treatment methods of impacted teeth will be reviewed, and the orthodontic treatment of impacted teeth will be comprehensively described to provide a reference for clinicians about the treatment of impacted teeth.

With the development of computer-aided surgery and rapid prototyping via 3D printing technology, digital surgery has rapidly advanced in clinical practice, especially in the field of oral and maxillofacial surgery. 3D printing technology has been applied to the functional restoration and reconstruction of the jawbone. Before surgery, a 3D digital model is constructed through software to plan the scope of the osteotomy, shape the bone graft and plan the placement of the implant. Additionally, 3D models of personalized surgical instrument guides are printed prior to surgery. With these 3D-printed models and guides, accurate excision of the jaw tumor, accurate placement of the grafted bone and precise placement of implants can be achieved during surgery. Postoperative evaluation of accuracy and function shows that 3D printing technology can aid in achieving the biomechanical goals of simultaneous implant placement in jaw reconstruction, and in combination with dental implant restoration, the technology can improve patients' postoperative occlusal and masticatory functions. Nevertheless, 3D printing technology still has limitations, such as time-consuming preparation before surgery. In the future, further development of 3D printing technology, optimization of surgical plans, and alternative biological materials are needed. Based on domestic and foreign literature and our research results, we have reviewed the process and clinical application prospects of jaw reconstruction via 3D printing technology to provide a reference for oral and maxillofacial surgeons.

Gingival recessions (GRs) result in root hypersensitivity, root surface caries, and esthetic problems. Various root coverage surgeries are being developed for periodontal plastic therapy. The tunnel technique (TUN) is one of the most widely applied surgeries due to its features of being minimally invasive, practical, excellent outcomes and long-term stability; however, there are still some limitations of this technique. The history and evolution from the envelope flap to TUN, including its efficiency when compared with coronally advanced flaps with a connective tissue graft (CTG), are reviewed in this paper. The limitations of TUN are discussed in consideration of our clinical experience; for example, there is high technique sensitivity when TUN is applied in GR>5 mm because of the great difficulty in covering the grafts. The advantages of surgical access, including vertical incisions in the vestibule, “W” type and pinhole access, are discussed for different situations. Mattress sutures and sling sutures in a single tooth or multiple teeth are applied in TUN. The different types of grafts, such as CTG, platelet-rich plasma, articular dermal matrix and xenogeneic collagen matrix, are described. Mechanical, chemical and biological conditioning of the root surface are recommended during surgery. Protecting the surgical area and taking antibiotics postoperatively are also very important. Finally, the modifications when TUN is applied with other kinds of techniques are discussed, including lateral closed TUN, laterally positioned flaps, double papilla flaps and frenuloplasty. Minimally invasive, esthetic, long-term stability and simplified techniques are the development trends of TUN in the future.

The functional reconstruction of large maxillofacial defects is a major issue in oral and maxillofacial surgery, and autologous bone transplantation is the main method. However, bone is readily absorbed following an autologous bone transplant. Even with vascular anastomosis, spontaneous osteoporosis of transplanted bone is still serious, which affects dental implantation and functional recovery. Therefore, osteoporosis of the grafted bone has become one of the main complications of jaw reconstruction, and there is no preventive measure. The problem that autologous bone with sufficient blood supply cannot avoid osteoporosis suggests that systemic factors such as nerves, which have been neglected in traditional methods, may regulate the internal environment of the transplanted bone. Based on previous studies on the regulation of mesenchymal stem cells by the neural microenvironment, we initiated a new surgical procedure for innervated and vascularized iliac bone flaps based on animal model and cadaver studies. In the innervated and vascularized iliac bone flap, vascular microanastomosis was performed in conjunction with microneuronal anastomosis between the simultaneously harvested ilioinguinal nerve (which innervates the iliac bone and is usually sacrificed and neglected in the conventional vascularized iliac bone flap) and the inferior alveolar nerve proximally and with the mental nerve distally. By conducting clinical retrospective studies and prospective randomized controlled trials, we proved that the novel method of simultaneous innervated iliac bone transplantation can not only prevent bone resorption but also restore the sensation of adjacent soft tissues such as the lip. This may solve the key problems of sensory loss and osteoporosis after mandibular reconstruction, ensure the success of dental implant dentures, and put forward the new concept of "blood supply + innervation" bi-system bone transplantation.

Ankylosis of primary molars is a kind of eruption abnormality of the teeth, where the periodontal membrane disappears, owing to a bony union between bone and root. Studies have shown that the common proportion of ankylosed primary molars is 1.3%~8.9% with an equal occurrence. In the primary dentition, the mandibular first primary molar is the most commonly affected tooth, while in the middle mixed dentition stage of development, the second primary molar is more affected. Its etiology may be related to genetics, signaling pathways of mineralization metabolism of local alveolar bone or cementum, cytokines secreted by epithelial rest cells of Malassez, and enhanced inflammatory reactions during physiological absorption of roots. Ankylosis of primary molars can be diagnosed by clinical symptoms and imaging and is classified as mild, moderate and severe according to the degree of infraocclusion. As it may cause a series of complications, such as occlusal disturbances, delayed exfoliation and incomplete alveolar process development, multidisciplinary treatment, including in the departments of pediatric dentistry, orthodontics, periodontics and prosthodontics, should be adopted, and long-term treatment is determined based on the patient's age, severity of infraocclusion, and presence of permanent teeth. This review summarizes the etiology, diagnosis, complications and treatment of ankylosed primary molars to provide a reference for the clinical diagnosis and treatment of decidual molar fixation.

After tooth extraction, labial contour collapses due to inevitable physiologic bone remodeling. To achieve optimal outcomes for pink esthetic treatment at anterior implant sites, bone or soft tissue augmentation has been advocated to maintain or reconstruct the labial tissue contour. When choosing soft tissue augmentation for esthetic restoration, it is necessary to strictly grasp the indications for surgery. Soft tissue augmentation to maintain or reconstruct the labial tissue contour could be considered in patients with healthy soft tissue and no bone defects or only mild horizontal bone defects. In immediate, early and late implant placement, the timing of soft tissue augmentation may vary. In immediate implantation, the labial bone plate is intact, so it is highly recommended to simultaneously manage soft tissue during implant placement. However, patients may have large bone defects with early or late implant placement. The risk of augmenting bone and soft tissue simultaneously is likely too high, and bone augmentation surgery is often performed at the first stage while soft tissue augmentation surgery is performed at the second stage. Therefore, soft tissue surgery is often carried out simultaneously with abutment connection. Currently, soft tissue augmentation is achieved mostly with adjacent autologous soft tissue grafts, such as free gingival grafts, subepithelial connective tissue grafts or pedicle palatal flaps, which are often accompanied by a second surgical area. The replacement of autogenous soft tissue grafting with new biological materials will become an inevitable trend. In this article, we analyze and summarize the indications, timing and different methods of soft tissue augmentation to maintain and reconstruct the labial contour.

Objective To study the clinical efficacy of biological ceramics (iRoot BP Plus ) and mineral trioxide aggregate (MTA) in direct pulp capping of mature permanent teeth, to provide referrence for clinical application. Methods Seventy-four patients with pulp exposure due to deep caries or reversible pulpitis in 75 mature permanent teeth were selected and were randomly divided into two groups. iRoot BP Plus were used as pulp capping agents in the treatment group and MTA were used as pulp capping agents in the control group respectively. The clinical efficacy and imaging analysis were performed at 1, 3, 6 and 12 months after operation. Treatment success rate of the two groups were calculated, and the influence of various factors including gender, age, tooth position, cavity, number and size of pulp exposure on the efficacy of direct pulp capping were analyzed. Results Sixty patients with 61 mature permanent teeth were selected. Twelve mouths after treatment, 61 teeth of 60 patents were completely investigated (iRoot group: 31 teeth 30 patients; MTA group: 30 teeth 30 patients). The success rates of the 2 groups were 90.3% (iRoot BP Plus) and 90.0% (MTA), respectively. There was no statistical difference between 2 groups (P>0.05). Statistical analysis also showed that gender, age, tooth position, cavity, number and size of pulp exposure had no significant difference between the two groups (P>0.05). Conclusion Both iRoot BP Plus and MTA are effective in direct pulp capping of mature permanent teeth with carious pulp exposure, while the operation of iRoot is simple and convenient.

Due to advances in digital technology, intraoral impressions have been increasingly used to fabricate implant restorations because of its simplicity, high efficiency, comfortableness and convenience. In clinical practice, the accuracy of intraoral impressions depends on various factors, including scanner technique, status of dentition and implants, auxiliary devices, materials and environment, which might influence its accuracy and limit its application. When applied to patients missing more teeth, its accuracy may be insufficient. It is suggested that intraoral impressions be used cautiously when there are multiple and far apart implants and that the scan body not be tightened excessively and that maintain appropriate environmental conditions. In this article, we have reviewed recent relevant literature and the factors affecting the accuracy of intraoral impressions for implant restoration.

Objective To explore the trajectory of the development of permanent caries in 12- to 16-year-old students in Liuyang and to provide a reference for the prevention and management of caries. Methods Primary and secondary school students who were registered within the Liuyang jurisdiction were screened for caries from September to November by the Liuyang Center for Disease Control and Prevention. A total of 7 297 students between the ages of 12 and 16 years with complete permanent dentition caries monitoring records and traceable deciduous dentition caries monitoring records were selected from 2013 to 2019, and a zero-inflated negative binomial-latent class growth model (ZINB-LCGM) was established to describe the trajectory of the development of individual caries using the decayed missing filled teeth (DMFT) indicators. Results DMFT of 12- to 16-year-old students in Liuyang were mainly decayed teeth (DT), with the majority occurring in the first permanent molar. According to the ZINB-LCGM model, the students were classified into three latent categories, "slow growth pattern" (28.55%), "rapid growth pattern" (6.59%), and "stable pattern" (64.86%), which followed different nonlinear caries growth trajectories. Females with deciduous teeth caries were more likely to have trajectories showing a “rapid growth pattern” and a “slow growth pattern”. There were significant differences in the trajectories between men and women, as well as between those with and without primary dentition caries. Conclusion The trajectory of the development of caries in 12-16-year-old students shows heterogeneity in terms of different developmental patterns of latent categories, suggesting that females with deciduous dental caries should receive more attention.

Porphyromonas gingivalis (P. gingivalis) is closely related to the occurrence and development of periodontitis. It is considered to be one of the important pathogens leading to alveolar bone resorption. At present, research on P. gingivalis mostly adopts standard laboratory strains whose genetic characteristics have been confirmed, are guaranteed and are traceable, such as ATCC 33277. The virulence phenotypes (endotoxin, firmbria, etc.) of clinically extracted isolates are quite different from those of standard strains, and the pathogenic effects and ability of the host are also widely different. In addition, P. gingivalis is considered to have a significant correlation with a variety of systemic diseases, and the virulence characteristics and pathogenic ability of different strains will have different effects on systemic diseases. However, at present, there is a lack of research on clinical strains and standard strains, and there is a lack of systematic comparison between the two sources of bacteria. In this paper, the differences in the virulence phenotypes and pathogenic effects between clinical isolates and standard strains of P. gingivalis in the last 5-10 years are reviewed. The aim is to elucidate the important virulence gene loci in the P. gingivalis gene sequence, which will play an important role in improving therapeutic methods and the development of related drugs.

Three-dimensional tooth segmentation is the segmentation of single-tooth models from a digital dental model. It is an important foundation for diagnosis, planning, treatment and customized appliance manufacturing in digital orthodontics. With the deep integration of artificial intelligence technology and big data from stomatology, the use of deep learning algorithms to assist 3D tooth segmentation has gradually become mainstream. This review summarizes the current situation of deep learning algorithms that assist 3D tooth segmentation from the aspects of dataset establishment, algorithm architecture, algorithm performance, innovation and advantages, deficiencies of current research and prospects. The results of the literature review showed that deep learning tooth segmentation methods could obtain an accuracy of more than 95% and had good robustness. However, the segmentation of complex dental models, operation time and richness of the training database still need to be improved. Research and development of the "consumption reduction and strong core" algorithm, establishment of an authoritative data sample base with multiple centers, and expansion of data application depth and breadth will lead to further development in this field.

Objective To discuss the correlation between the extraction timing of mesiodens and the orthodontic treatment duration of its eruption-related complications in children to provide a reference for the clinic. Methods The mesiodentes of 187 children were classified as eruption type (typeⅠ), dental crown impacted type (type Ⅱ), interdental impacted type (type Ⅲ), and dental root impacted type (type Ⅳ). According to the timing of extraction, mesiodentes in typeⅠ, type Ⅲ, and type Ⅳ were divided into Groups A: before the eruption of the adjacent central incisor and B: after the eruption of the adjacent central incisor. Mesiodentes in type Ⅱ were divided into Group A: before the eruption of the contralateral central incisor and B: after the eruption of the contralateral central incisor. Eruption-related complications and orthodontic treatment durations caused by mesiodens were statistically analyzed. Results There were 106 cases of displacement, 28 cases of failed eruption, 27 cases of tooth rotation, and 26 cases of individual cross-bite among the eruption-related complications caused by mesiodens. The mean orthodontic treatment cycle in Group A of type Ⅰ (7.07 ± 2.45 month), Group A of type Ⅱ (6.57 ± 1.12 month), and Group A of type Ⅲ (6.95 ± 2.52 month) were lower than that in Group B of type Ⅰ (9.67 ± 3.04 month), Group B of type Ⅱ (10.25 ± 1.29 month), and Group B of type Ⅲ (9.33 ± 3.26 month), and the differences were statistically significant (P<0.01). Meanwhile, there was no significant difference in the mean orthodontic treatment duration between Groups A (6.00 ± 0.94 month) and B (6.33 ± 0.80 month) of type Ⅳ (P>0.05). Conclusion In most cases, the mesiodens are removed before the eruption of the adjacent central incisor, which can reduce the duration of orthodontic treatment for eruption-related complications in children.

Objective To investigate the diagnosis and treatment for oral mucositis induced by low-dose methotrexate and to provide a reference for clinicians. Methods A case of severe chemotherapy-induced oral mucositis caused by short-term use of low-dose methotrexate (the maximum cumulative dose within 1 week) was reported and reviewed in combination with the literature. Results The patient was treated with low-dose methotrexate (2.5 mg orally every other day at weeks 1, 2, and 4; the third week, 2.5 mg each time for 3 consecutive days for twice, with a maximum cumulativedose of 15 mg within a week). After irregular medication for approximately three weeks, the patient gradually developed severe erosion of the lips, pain, difficulty eating, and skin erosion on both legs. Methotrexate was stopped after admission, and local symptomatic treatments such as Kangfuxin solution were given. Recombinant human granulocyte colony-stimulating factor was used systemically when combined with neutropenia. After treatment, the chemotherapy-induced oral mucositis and skin lesions were improved. A literature review shows that chemotherapy-induced oral mucositis is a toxic reaction to high-dose methotrexate, while cases of severe chemotherapy-induced oral mucositis caused by low-dose methotrexate are rare. Studies have found that the more risk factors patients have, such as poor local oral conditions and systemic diseases such as liver and kidney dysfunction and diabetes, the higher the risk of chemotherapy-induced oral mucositis. Clinicians should cooperate with dentists to address oral diseases as much as possible before using chemotherapy drugs. In addition, when ordering patients to take methotrexate, we should pay attention to the patient's general condition and susceptibility factors, standardize the frequency and dose of administration, adopt personalized treatment plans, and give patients detailed medication education to prevent the occurrence of adverse consequences caused by medication errors. If methotrexate poisoning occurs, the drug should be stopped in time, detoxification and active symptomatic and supportive treatment should be given. Basic oral care, cryotherapy, laser therapy, nutritional support and analgesic drugs are common treatments for chemotherapy-induced oral mucositis. Systemic administration of granulocyte colony-stimulating factor may be considered when accompanied by neutropenia. Conclusion It is necessary to be alert to the occurrence of severe chemotherapy-induced oral mucositis caused by low-dose methotrexate in clinical practice.

Objective To explore the effects of red LED light mediated by the Kelch-like ECH-associated protein 1-nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (KEAP1-NRF2/HO-1) pathway on osteogenic differentiation and oxidative stress damage of human periodontal ligament stem cells (hPDLSCs) induced by high glucose, which provides a basis for the application of red light-emitting diode (LED) light in cell antioxidative damage. Methods hPDLSCs were identified by flow cytometric analysis, alkaline phosphatase (ALP) staining and Alizarin red-S staining; hPDLSCs were pretreated in a high glucose environment for 48 hours and irradiated with 1, 3, or 5 J/cm² red LED light. A CCK-8 assay was performed to choose the radiant exposure that had the strongest effect on promoting the cell proliferation rate for subsequent experiments. hPDLSCs were divided into a control group, a high glucose group and a high glucose+light exposure group. ALP staining, ALP activity, Alizarin red-S staining and quantitative calcified nodules were used to detect the osteogenic differentiation of hPDLSCs; qRT-PCR and Western blot were used to detect the gene and protein expression levels of ALP, runt-related transcription factor 2 (RUNX2) and osterix (OSX); the relative mRNA expression levels of antioxidant enzyme-related genes superoxide dismutase 2 (SOD2) and catalase (CAT) in hPDLSCs were detected by qRT-PCR; reactive oxygen species (ROS) levels were detected by fluorescence microscopy and flow cytometry; the tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels in cell supernatants were detected by ELISA; the NRF2-specific inhibitor ML385 was used to inhibit the NRF2 pathway; ALP staining and ALP activity were used to detect the markers of early osteogenic differentiation; qRT-PCR was used to detect the gene expression of ALP, RUNX2 and OSX; and the protein expression levels of KEAP1, NRF2 and HO-1 were detected by Western blot. Results Identified, and irradiant exposure of 5 J/cm² was chosen for subsequent experiments. Red LED light irradiation (5 J/cm²) improved the osteogenic differentiation of hPDLSCs induced by high glucose (P<0.05), increased the mRNA and protein levels of ALP, RUNX2 and OSX (P<0.05), upregulated the mRNA expression levels of SOD2 and CAT (P<0.05), reduced the levels of ROS (P<0.05), and reduced TNF-α and IL-1β levels in the cell supernatants (P<0.05). When ML385 was added to inhibit the NRF2 pathway, the ALP activity of cells was decreased (P<0.05); the gene expression levels of ALP, RUNX2 and OSX were downregulated (P<0.05); the protein level of KEAP1 was upregulated (P<0.05); and the protein levels of NRF2 and HO-1 were downregulated (P<0.05). Conclusion Red LED light may promote the proliferation and osteoblastic differentiation of hPDLSCs induced by high glucose through the KEAP1-NRF2/HO-1 pathway and reduce the oxidative stress damage to hPDLSCs induced by high glucose.

Eutrophils are the first innate immune cells to reach the site of inflammation. Neutrophils produce neutrophil extracellular traps (NETs) that can quickly capture and limit the spread of pathogens, facilitating the removal of pathogens and their debris. Neutrophils in the oral cavity are specifically transformed from circulating neutrophils in the blood, and the number of NETs released by oral neutrophils is much higher than that of circulating neutrophils, thus better maintaining the balance of the oral microenvironment. As a bimorphic fungus, only the mycelium phase of Candida albicans can induce NETs, which is related to the neutrophils' ability to sense the size of pathogenic microorganisms through neutrophil elastase. However, spherical Staphylococcus aureus are much smaller than Candida albicans, and they can still induce NETs. Porphyromonas gingivalis, as one of the microorganisms in the periodontitis complex, induces fewer NETs than Streptococcus oralis and Actinomycetes, which are two common oral microorganisms, and there may be a mechanism allowing them to escape neutrophilic immunity in the early stage of periodontitis. Although the two main pathways of NET production have been studied in detail, the mechanisms involved in the induction of NETs by different microorganisms, especially from oral neutrophils, are not well understood. This review describes the mechanism of the immune effects of pathogenic microorganisms on neutrophil NETs in the oral cavity, providing a reference for the search for therapeutic targets and the development of key drugs for treating oral infectious diseases.

Objective To investigate the histological damage recovery of temporomandibular joint condylar cartilage caused by chronic unpredictable moderate stress, aiming to provide an experimental basis for the prevention and treatment of temporomandibular disorder. Methods This animal experiment was approved by the Laboratory Animal Ethical Inspection, School of Stomatology, The Fourth Military Medical University (No. 2020081). 60 male SD rats were randomly divided into control group, stress group, and 2-, 4- and 8-week post-stress recovery groups. Rats were subjected to chronic unpredictable moderate stress (CUMS) for 8 weeks including damp sawdust for 24 hours, tilted cage for 12 hours, noise for 4 hours, light/dark cycle reversal, water immersion, tail clamp, and restraint stress. The serum assessment, behavioral tests, histological and ultrastructural observation were performed 2-, 4- and 8-weeks after stress factors were removed. Serum levels of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were determined with ELISA. The sucrose preference test (SPT) and the forced swim test (FST) were used to assess the depressive-like behavior. The expression level of interleukin-1α (IL-1α) and matrix metalloproteinases-3 (MMP-3) were determined by Immunohistochemistry and Western blot. Results At the end of 8 weeks of CUMS, the serum levels of CORT and ACTH were significantly higher in stress group compared with control group (P<0.01). The sucrose preference decreased significantly and the immobility time increased significantly in the stressed rats compared with those in the control group, indicating a successful establishment of CUMS. The condylar cartilage showed significant degenerative changes, with disorganized collagen fibers and reduced proteoglycan synthesis on the cartilage surface. IL-1α and MMP-3 were expressed in the intracellular and extracellular matrix of the condylar cartilage, and their expression levels were increased (P<0.01). After 2 weeks of stress removal, the serum levels of CORT and ACTH were decreased but higher than control group (P<0.01), and behavioral changes were still different from the control group (P<0.01); the loosened collagen fibers could still be seen on the surface of condylar cartilage, and some free cell areas were visible within the proliferative layer; additionally, IL-1α and MMP-3 expression in the condyle was reduced in all layers of cartilage when compared with the stress group, but was still higher than in the control group (P<0.01). After 4 weeks of stress removal, the serum levels of CORT and ACTH changes returned to normal levels and behavioral changes were still different from control group (P<0.05); a few collagen fibers could be seen on the surface of the condylar cartilage and the expressions of IL-1α and MMP-3 decreased significantly compared with the stress group (P<0.01), with the similar level of IL-1α (P>0.05) and higher expression of MMP-3 comparing with the control group (P<0.01). After 8 weeks of stress removal, behavioral changes returned to normal levels, with no statistically significant differences compared with the control group (P>0.05). The condylar collagen fibers increased and showed a corrugated pattern, and no serious subchondral bone damage as well as irreversible damage occurred. Both of the expression levels of IL-1α and MMP-3 approached those of the control group after 8 weeks of stress removal (P>0.05). Conclusion The behavioral changes and condylar cartilage damage caused by CUMS could be self-repaired. The decline in IL-1α and MMP-3 expression may be one of the intrinsic mechanisms of this self-repair process.

Objective To investigate the clinical features, diagnosis and treatment of osteomyelitis of the jaw caused by an actinomycotic infection and to provide a reference for clinical diagnosis and treatment. Methods A case of osteomyelitis in the bilateral maxilla and the left zygomatic bone and arch caused by a mixed bacterial infection dominated by Actinomycetes was reviewed and analyzed in combination with the literature. Results The patient had left upper posterior tooth pain with repeated left facial swelling for 7 months. The patient's left face was swollen before surgery, the left maxillary alveolar bone was necrotic, and the upper palate showed fistula discharge. A maxillofacial magnetic resonance imaging scan excluded tumors and other space-occupying lesions. According to CBCT images, the initial diagnoses were left infraorbital space infection and osteomyelitis of the bilateral maxillary, the left zygomatic bone, the left zygomatic arch and the lateral orbital wall. Necrosis of the left maxilla and the zygomatic bone was excised, the focus was cleared and the focal tooth was extracted under general anesthesia. Histopathological results confirmed osteomyelitis and actinomycotic infection. Anti-inflammatory therapy with penicillin sodium was given before surgery, and piperacillin sodium and tazobactam sodium, dexamethasone sodium phosphate, tranexamic acid and mecobalamine were given after surgery. The patients' 6-month follow-up results showed that the maxillofacial shape was basically symmetrical; no ulceration, pus or abnormal secretion was found in the skin or intraoral mucosa; and the surgical area showed good recovery. A review of the relevant literature showed that Actinomyces is an opportunistic pathogen, and factors such as trauma and dental infection have been implicated in the pathogenesis of osteomyelitis. In addition to surgery, antibiotics are used to treat the disease and multidisciplinary symptomatic treatment combined with supportive treatment is required to achieve a better prognostic effect. Conclusion Actinomycotic osteomyelitis occurring in the maxilla and the zygomatic bone is an extremely rare disease that can be diagnosed by clinical manifestations, bacteriological examination and biopsy. Appropriate and effective penicillin drugs should be given at the initial stage of treatment, more sensitive antibiotics should be selected according to the results of the drug sensitivity test, and the lesions should be surgically removed when the patient's condition improves. Active symptomatic and supportive treatment should be performed during the treatment period.

Lack of alveolar bone height is a major challenge for dental implants. In recent years, the use of "sandwich" osteotomy to increase alveolar bone height has become a topic of discussion within the research community. In theory, "sandwich" osteotomy is a U-shaped osteotomy in the bone defect area, to preserve the blood supply of the mucoperiosteal on the lingual side and to create an artificial "four-wall bone bag" to build a favorable space for osteogenesis and to increase the height of the alveolar bone. Histological studies have shown that the osteogenesis speed of "sandwich" osteotomy is fast, and the bone is good. Sandwich osteotomy is suitable for buccal-lingual alveolar bone height defects less than 50% of the implant length or for unilateral defects more than 50% of the implant length. In the operation of "sandwich" osteotomy, the horizonal incision should be 10-12 mm below the crest of the buccal alveolar ridge. The design of the osteotomy line should ensure the height of the osteotomy block and that the mandibular canal does not sustain damage and that it fits the shape of the bone defect. There was no significant difference in the osteogenic effect of different types of bone graft materials used for "sandwich" osteotomy. The osteotomy block was rigorously fixed by a titanium plate, titanium nail, implant and other materials, and finally, the intraoperative area was tensioned and sutured. The effect of bone augmentation was evaluated and compared with other bone augmentation techniques; the evaluation showed that sandwich osteotomy was better for moderate vertical bone defects. This technique is highly sensitive and postoperative transient sensory loss is common. With advances in technology, the application of digital technology and ultrasonic bone knives, the risk of complications is greatly reduced and advances in digital osteotomy will promote apply of "sandwich" osteotomy, which will become a popularized technique for clinical alveolar bone augmentation.

Objective The aim of this study was to investigate the effect of changes in nasal tip protrusion on the sense of upper lip protrusion in different populations and to provide a reference for the improvement of soft tissue beauty. Methods Informed consent and portrait authorization were obtained from the model. A female model whose face met the criteria was selected, and a 3D model of her was obtained using a 3D stereo camera. Based on the original model, ZBRUSH2019 software was used to simulate changes in nose tip protrusion. Then, 9 segments of facial dynamic rotation videos were produced, and an electronic questionnaire was created through a questionnaire website to evaluate the effect of different nose tip protrusions on perceived upper lip protrusion. Randomly selected orthodontic patients, orthodontics professionals and general adults completed the electronic questionnaire. In the questionnaire, a Visual Analog Scale was used to evaluate the perceived degree of protrusion of the upper lip. The higher the score, the more prominent the upper lip of the model in the image. The questionnaire data were statistically analyzed using a generalized linear mixed model. Results As the nasal tip position became progressively more retracted, the subjects' upper lip protrusion scores increased. Among male subjects, the results showed that the general population thought that the upper lip protrusion was higher than the patients did when the nasal tip protrusion was +6 mm and +4.5 mm (P = 0.023, P = 0.047). When the nasal tip protrusion was +6 mm, the scores of the general population were higher than those of the orthodontics professionals (P = 0.023). However, when the nasal tip variable was -6 mm, their score was lower than that of the patients (P = 0.003), and there was no significant difference in other retest distances between groups (P>0.05). Conclusion When the protrusion of the nasal tip decreased, the three groups experienced a visual illusion of upper lip protrusion. When the nasal tip protrusion is too large, the general population perceived the visual illusion of the upper lip protrusion as being more obvious.

Objective To investigate the effect of isoprene cysteine carboxymethyltransferase (ICMT) gene on the migration and invasion of salivary adenoid cystic cancer cells (SACC) and the related mechanism, to provide experimental evidence for molecular targeted therapy of SACC. Methods Adenoid cystic cancer cells SACC-LM and SACC-83 were cultured in vitro, and siRNA was transfected into human SACC-LM and SACC-83 cells (experimental group) by transient transfection of a liposome vector. A blank control group and negative control group were set up respectively (transfected NC-siRNA). qRT-PCR was peformed to measure the mRNA expression of ICMT and RhoA in each group after transfection and to determine the silencing efficiency. The expression of ICMT, membrane RhoA, total RhoA, matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) and Rho associated with coiled helical binding protein kinase 1 (ROCK1) in each group was detected by Western blot. The proliferation abilityies of SACC cells was detected by CCK-8 assay. The migration and invasion ability of SACC cells were detected by comparing the relative healing area of cell scratch assay and the number of Transwell assay cells. Results After transfection of ICMT-siRNA into SACC-LM and SACC-83 cells, the expression of ICMT gene and protein in the experimental group was significantly decreased compared with the negative control group and blank control group (P<0.05), but there were no significant differences in the expression of RhoA gene and total protein among all groups (P>0.05). The expression of RhoA membrane proteins, ROCK1, MMP-2, MMP-9 in the experimental group was significantly decreased compared with that in the negative control group and blank control group (P<0.05). Cell proliferation ability was significantly decreased (P<0.05). The migration and invasion abilities were significantly decreased (P<0.05). Conclusion In vitro silencing of ICMT gene can effectively inhibit the migration and invasion of human SACC-LM and SACC-83 cells, and the mechanism may be related to RhoA-ROCK signaling pathway.

It has been traditionally believed that a 1:1 cortical bone remodeling/tooth movement ratio has been preserved during orthodontic treatment for tooth movement, with the alveolar bone on the tension side growing and the alveolar bone on the pressure side resorbing to maintain the balance of the alveolar bone. However, recent studies have shown that alveolar bone loss has been found in patients who have undergone orthodontic treatment, suggesting that the alveolar bone does not change as the teeth change over time. Whether the morphology of the alveolar bone will change when the anterior teeth are moved has been the clinical focus. The changes of anterior alveolar bone in patients who have undergone tooth extraction after orthodontic treatment were summerized by literature review in this paper. The results of the review showed that the alveolar bone at the lingual/palatal root-cervical site of the anterior root is more prone to bone loss after extensive movement of the anterior teeth. With the development of imaging technology, CBCT is now more commonly used for analysis instead of two-dimensional images for measurement, as its results are more accurate. However, there are few multifactorial studies in which CBCT has been used to assess the morphological changes in the alveolar bone. The focus of future research is to compare the long-term changes in the anterior alveolar bone of patients of different ages based on three-dimensional imaging, and to study the correlation between different skeletal features, tooth movement patterns and alveolar bone remodeling.

Objective To investigate the biomechanical effects of upper lip pressure on the maxilla in patients with a unilateral alveolar cleft and provide evidence for clinical diagnosis and treatment. Methods A 3D finite element maxillary model was generated based on cone beam CT (CBCT) data from an 11-year-old female patient with a unilateral alveolar cleft. Two different kinds of upper lip pressure, postsurgery pressure and normal pressure, were applied to the model. The displacement and stress of each reference node were compared and analyzed. Results By loading upper lip pressure, the maxillary alveolar crest rotated toward the defect and was displaced downward and backward. The displacement of the noncleft side was greater than that of the cleft side and it decreased gradually from the anterior to the posterior. The stress was concentrated on the anterior portion of the alveolar crest. The stress on the noncleft side was greater than that on the cleft side and it decreased gradually from the anterior to the posterior. The maximum stress was concentrated on the palate around the defect. The displacement and stress in the postsurgery group were greater than those of the normal group (P<0.05). Conclusion By loading upper lip pressure, the maxilla demonstrated asymmetry three-dimensionally. The adverse effects on the maxilla could be mitigated by reducing the upper lip pressure.

Antimicrobial peptides have antibacterial effects on various pathogenic microorganisms, including natural antimicrobial peptides and synthetic antimicrobial peptides. According to the structure of natural antimicrobial peptides, synthetic antimicrobial peptides can be obtained by recombining different functional domains, adjusting the original amino acid sequence, or completely redesigning the peptides from scratch. Antimicrobial peptides can inhibit the growth of various cariogenic microorganisms and the formation of microbial biofilms. They also reduce acid production and acid resistance of microorganisms. Natural antimicrobial peptide genes can be used as genetic susceptibility markers for predicting the development of caries, thus, showing potential applications in the prevention and treatment of dental caries. The instability of natural antimicrobial peptides and the inability to achieve targeted sustained release limit their application in the prevention and treatment of oral caries. Synthetic antimicrobial peptides can enhance their stability and the antibacterial effect. Synthetic antimicrobial peptides can also be polymerized with common oral adhesives to reduce the incidence of microleakage after filling treatment for caries and to prevent the occurrence of secondary caries. The pH-sensitive antimicrobial peptides are slowly released to promote remineralization in the process of caries. However, the safety and biocompatibility of synthetic antimicrobial peptides are worse than those of natural antimicrobial peptides. Moreover, the combined effect of antibacterial peptides and anticaries drugs, such as fluoride, is still uncertain. Therefore, in this paper, we will review the design methods, application and underlying mechanisms of antimicrobial peptides to introduce novel methods and ideas for the prevention and treatment of dental caries.

Cell therapy based on mesenchymal stem cells (MSCs) has been a hot research topic in recent years, including the traditional cell therapy strategy based on living cells and the new cell-free therapy strategy based on soluble proteins or bioactive molecules such as extracellular vesicles (EVs). At present, MSC-induced cells have mature functions and specific structures, and insitu transplantation combined with biomaterials or organic technology has greatly improved the settlement rate and function. On the other hand, as the large-scale culture technique and EVs separation technique evolve, it is possible to obtain a large number of pure EVs, and EVs are gradually becoming a hot spot of current research. An increasing number of studies have shown that the therapeutic effect of MSCs not only occurs by implantation and differentiation but also manifests as the paracrine effect of MSCs. In this review, we discuss the emerging outcomes of cell therapies and acellular therapies to alleviate these pathological conditions.

Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa. The pathogenesis of OLP is still unclear. Immune abnormalities mediated by T cells and related cytokines play a crucial role in the pathogenesis of OLP. In recent years, glycolytic metabolism-related transporters, enzymes and regulators, such as glucose transporter-1 (Glut1), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), lactate dehydrogenase A (LDHA), mammalian target of rapamycin (mTOR) and hypoxia inducible factor-1α (HIF-1a), have attracted an increasing amount of attention in OLP by regulating the proliferation and differentiation of T cells and the secretion of inflammatory factors. It has been shown that 2-deoxy-D-glucose (2-DG) or rapamycin (RAPA) inhibits the glycolytic metabolism of T cells and then inhibits OLP. This article reviews the research progress of glycolytic metabolism-related transporters, enzymes and regulatory factors in OLP in recent years.

Objective To investigate the effect of erythropoietin producing hepatocyte kinase receptor ligand B2-erythropoietin producing hepatocyte kinase receptor B4 (EphrinB2/EphB4) on the osteogenic differentiation of MC3T3-E1 cells in a hypoxic environment to provide experimental evidence for hypoxia regulation of osteoblast differentiation. Methods Control groups and cobalt chloride (CoCl₂)-induced hypoxia groups were set up first. qRT-PCR was used to detect the mRNA expression of the osteogenic markers alkaline phosphatase (ALP), collogen1 (COL I), runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN). ALP staining was used to detect the activity of cell alkaline phosphatase after osteogenic induction. The mRNA and protein expression levels of hypoxia inducible factor-1α (HIF-1α), EphrinB2 and EphB4 in the two groups were detected via qRT-PCR and Western blot. Then, the CoCl₂ + inhibitor group was established. NVP-BHG712, an EphB4 phosphorylation inhibitor, was added to this group to prevent EphrinB2 from binding to EphB4 and producing signals. qRT-PCR and Western blot were used to detect the mRNA and protein expression of osteogenic markers, including ALP, RUNX2, COL I, and OCN. ALP staining and Alizarin red S staining were used to measure osteoblast differentiation and mineralization. Results Compared with the control group, the mRNA expression of the osteogenic differentiation markers ALP, RUNX2, COL-1, and OCN in MC3T3-E1 cells increased, and ALP activity and mineralization were enhanced under CoCl₂-induced hypoxia in vitro (P<0.05). Additionally, the expression of HIF-1α, EphrinB2 and EphB4 was upregulated at the mRNA and protein levels under hypoxia (P<0.05). When NVP-BHG712 was used to block the connection between EphrinB2 and EphB4, the expression of osteogenic markers and ALP activity and mineralization were decreased (P<0.05). Conclusion EphrinB2/EphB4 can promote osteogenic differentiation of MC3T3-E1 cells and increase the expression of osteogenic markers and tissue mineralization in a hypoxic environment.

Objective To investigate the application of indocyanine green in near-infrared fluorescence imaging to determine the scope of necrotic bone resection in osteoradionecrosis of the jaw and to provide a reference for clinicians. Methods Eight patients with osteoradionecrosis of the jaws were enrolled. Indocyanine green was intravenously injected through the elbow vein 10 minutes before osteotomy. After conservative resection of necrotic bone lesions based on imaging results, the scope of potential dead bone resection in the area of low fluorescence intensity was gradually expanded at an initial distance of 0.3 cm. Near-infrared fluorescence imaging and fluorescence intensity determination of bone cross-section were performed before and after extended resection. Statistical differences were analyzed. All patients with osteonecrosis underwent regular follow-up to evaluate the postoperative efficacy. Results Indocyanine green was injected into all 8 patients with osteoradionecrosis for near-infrared fluorescence imaging and the scans were clear; the fluorescence intensity of fresh bone wounds with an expanded mandibular resection range of (0.95 ± 0.14) cm was (226.2 ± 15.8) au, which was higher than that based on intraoperative macroscopic observation and radiological results (108.8 ± 3.4) au, (t = 20.718, P<0.001). The postoperative follow-up improvement rate of 8 patients was 87.5%. Conclusion Near-infrared fluorescence imaging with indocyanine green can assist in the successful removal of necrotic bone until fresh bleeding of the jaw wound occurs, which has important clinical value in defining the resection range of osteoradionecrosis of the jaw.

Objective To investigate the application value of 3D microscope in vascular anastomosis in oral and maxillofacial surgery, to provide a reference for clinicians. Methods Eighty-seven cases of free flap reconstruction in oral and maxillofacial surgery were retrospectively included, including 30 cases in the 3D microscope group and 57 cases in the optical microscope group. The differences in intraoperative vascular anastomosis time, postoperative flap survival rate and doctor evaluation scores between the 3D microscope group and the optical microscope group were compared and statistically analyzed, and the feasibility of using three-dimensional microscope in surgery was evaluated. Results The arterial anastomosis time was (26.53±3.83) min/root in the 3D microscope group and (24.88 ± 2.97) min/root in the optical microscope group, and the difference was statistically significant (P<0.05). The venous anastomosis time was (30.68 ± 3.51) min/root in the three-dimensional microscope group and (28.70 ± 2.91) min/root in the optical microscope group, and the difference was statistically significant (P<0.05). There was no significant difference in the survival rate of flaps between the 3D microscope group (n = 28, 93.33%) and the optical microscope group (n = 53, 92.98%) (P>0.05). The doctor's evaluation scores of visual fatigue, training and learning, operative difficulty index, image sharing in the three-dimensional microscope group were higher than those in the optical microscope group, and the differences were statistically significant (P<0.05). Conclusion 3D microscope has good reliability and safety in surgery, a strong sense of three-dimensionality, and the convenience of teaching and training. It can be well applied to vascular anastomosis in oral and maxillofacial surgery.

Objective To investigate the distribution characteristics and functional genes of cariogenic bacteria in oral microorganisms of patients with type 2 diabetes mellitus and to improve the understanding of the relationship between type 2 diabetes mellitus and dental caries. Methods The experimental group included 10 patients with type 2 diabetes treated in the Department of Endocrinology, the First Affiliated Hospital of Air Force Medical University. The normal control group included healthy oral subjects without type 2 diabetes in the community population (10 cases). Samples of supragingival plaque from patients with type 2 diabetes mellitus and normal controls were collected and sequenced. Bioinformatics and statistical analysis of cariogenic bacteria such as Streptococcus mutans, Lactobacillus, Actinomyces viscosus and Candida albicans were carried out. Results There were slightly fewer cariogenic bacteria such as Streptococcus mutans, Lactobacillus, Actinomyces viscosus and Candida albicans in supragingival plaque samples of type 2 diabetic patients than in normal controls, but the difference was not statistically significant (P>0.05). The results of KEGG pathway functional metabolic differences showed that the metabolic pathways of D-arginine and D-ornithine metabolism, biofilm formation-Escherichia coli, carolactam degradation and arginine biosynthesis were more abundant in the T2DM group than in the normal control group, while metabolic pathways such as tyrosine metabolism, selenocompound metabolism and pyruvate metabolism showed the opposite trend. Conclusion There was no significant difference in the content of cariogenic microorganisms between type 2 diabetic patients and normal control group. The differential metabolic pathways of the functional genes indicated that an increase in the arginine metabolic pathway was beneficial to the maintenance of acid-base balance in the oral microecological environment.

Objective To investigate the effect of pathogenic bacterium-Porphyromonas gingivalis (P.g) on the proliferation and inflammatory factor expression of human colorectal cancer Caco-2 cells, to determine whether the Janus kinase 2-signal transducers and activators of transcription 3 (JAK2-STAT3) pathway is involved in the regulation of Caco-2 cell proliferation by P.g and to provide an experimental basis for further exploring the relationship between P.g and colorectal cancer. Methods Caco-2 cells were cultured in vitro, and P.g at different multiplicities of infection (MOIs) (0, 1, 10, 25) was selected to stimulate for 12, 24 and 48 h. The effect of P.g on the proliferation of Caco-2 cells was detected by CCK8. The stimulation time was set as 12, 24 and 48 h. MOI=0 was the control group, and MOI=1, 10 and 25 comprised the experimental group. qRT-PCR and Western blot were used to detect the changes in interleukin-6 (IL-6), interleukin-10(IL-10), JAK2 and STAT3 gene and protein (phosphorylated protein) levels in each group. Results After P.g infection of Caco-2 cells, P.g had a sustained stimulatory effect on the cells for 12, 24 and 48 h at MOI=1 and MOI=10 compared with the control group. Compared with that in the control group, the expression of pro-inflammatory factor IL-6 and related proliferative pathway protein JAK2 and STAT3 in Caco-2 cells with P.g infection increased in a concentration- and time-dependent manner (P<0.05). Additionally, the expression of IL-10, an anti-inflammatory factor, in Caco-2 cells infected with P.g decreased (P<0.05). After the addition of the JAK2 inhibitor AZ960, the proliferation of Caco-2 cells infected with P.g decreased, and the mRNA expression of STAT3 and JAK2 and the protein expression of p-STAT3 and p-JAK2 decreased (P<0.05). Conclusion P.g can promote the proliferation of the colorectal cancer cell line Caco-2, and the effect of P.g on Caco-2 cells may promote cell proliferation through the JAK2-STAT3 pathway while promoting the expression of the proinflammatory factor IL-6 and inhibiting the expression of the anti-inflammatory factor IL-10, creating an inflammatory environment conducive to cell proliferation, which may be the mechanism by which P.g affects the proliferation of Caco-2 cells.

Objective To evaluate the effect of anatomical healing abutments for mandibular first molars on the morphological changes of gingival soft tissue after implant restoration, as well as on peri-implant gingival molding, food ingrowth and patient satisfaction, to provide a basis for clinical selection. Methods Twenty-six patients who received implant restoration for a single missing mandibular first molar between September 2020 and September 2021 at the Oral Implant Center of Changsha Stomatological Hospital were randomly divided into a control group (13 cases with 14 implants) and a trial group (13 cases with 14 implants), of which 12 were male and 14 were female; the trial group had anatomical healing abutments applied for 4 weeks and then underwent crown restoration, while the control group finished five time points (before the second stage surgery, 4 weeks after the second stage surgery, immediately after the crown restoration, 4 weeks after the crown restoration, and 12 weeks after the crown restoration). A 3Shape intraoral scanner was used to scan the jaw before and 4 weeks after the second stage surgery to quantify the soft tissue changes and compare the effect of the healing abutment on gingival molding between the two groups. The incidence of food impaction was recorded and compared between the two groups at 4 weeks and 12 weeks after crown restoration. Patient satisfaction was recorded and compared between the two groups immediately after crown restoration, 4 weeks after crown restoration and 12 weeks after crown restoration. Results Four weeks after implant surgery, it was observed that the gingival proximal and distal gingival papillae increased on the coronal side in the test group compared to the control group, 0.50 (0.26, 0.72) mm in the near-medium test group and 0.27 (0.24, 0.38) mm in the control group, with a statistically significant difference (P = 0.029), and 0.48 (0.26, 0.62) mm in the far-medium test group and 0.23 (0.13, 0.39) mm in the control group, with a statistically significant difference (P = 0.004). There was no statistically significant difference (P>0.05) in the buccolingual to gingival margin apex to coronal molding or in the buccolingual to lingual soft tissue at 0, 1, or 2 mm of the root of the middle 1/3 apex of the buccal and lingual gingival margins between the two groups. Compared to the control group, there was no statistically significant difference in the incidence of food impaction observed 4 weeks and 12 weeks after crown restoration in the test group (P>0.05). The satisfaction scores were higher in the trial group than in the control group immediately, 4 weeks, and 12 weeks after crown restoration, and the difference between the groups was statistically significant (P < 0.05). Conclusion The anatomical healing abutment for the implant mandibular first molar was superior to the finished healing abutment in terms of soft tissue contouring with an increase in the coronal aspect of the proximal and distal gingival papillae, resulting in high patient satisfaction.

Objective To explore the preventive effect of nicotinamide (NAM) on cleft palate induced by all-trans retinoic acid (RA), to provide research evidence for the prevention of cleft palate. Methods The mouse cleft palate model was induced by intragastric administration of 70 mg/kg all-trans retinoic acid at embryonic day 10.5 (E10.5) in the control group. The mouse cleft palate model was treated by caudal vein injection of 20 mg/kg NAM at E8.5 to E13.5 in the experimental group (1). The cleft palate model was treated by caudal vein injection of 40 mg/kg NAM at E8.5-E13.5 in the experimental group (2). The cleft palate of fetal rats was observed by laparotomy on E16.5 and statistically analyzed. Annexin V-FITC/PI double staining was used to detect the apoptosis of mouse embryonic palatal mesenchyme (MEPM) cells treated with RA 1 μmol/L (RA 1 group), NAM 200 μmol/L (NAM 200 group), and both NAM 200 μmol/L and RA 1 μmol/L (NAM 200+RA 1 group) for 24 hours by flow cytometry and the apoptosis rate in groups were compared. Culture without RA or NAM was used as a control. Results The cleft palate rate in the control group was 98%. The cleft palate rate in experimental group (1) was 87%. There was no significant difference between groups (P>0.05). The cleft palate rate in the experimental group (2) was 63%, compared with the control group, there was a significant difference (P<0.01). The cell apoptosis rate was 16.53%±2.89% in the CONTROL group. The cell apoptosis rate was 22.9%±1.85% in the RA 1 group, which was a significant increase compared with the CONTROL group (P<0.01). The apoptotic rate of the NAM 200 group was 9.23%±1.39%, which was a significant decrease compared with NA 1 group (P<0.01). The apoptosis rate of the NAM 200+RA 1 group was 14.9%±7.67%, which was a significant decrease compared with the RA 1 group (P<0.01). Conclusion NAM can prevent cleft palate. 40 mg/kg nicotinamide during pregnancy is an effective concentration for the prevention of RA-induced cleft palate. The mechanism by which NAM prevents cleft palate may be that NAM inhibits RA-induced apoptosis of MEPM cells.

Periodontitis is a widespread disease worldwide, with the primary cause of tissue loss being an immune inflammatory response mediated by bacteria. Increasing evidence has revealed a significant correlation between mitochondrial dysfunction and the occurrence and progression of periodontitis. This paper provides a review of current research on the role of mitochondrial dysfunction in the occurrence and development of periodontitis and related therapies from the perspectives of oxidative stress, inflammatory responses, and the regulation of mitochondrial homeostasis. Mitochondria are the main source and target of cellular reactive oxygen species. Mitochondrial dysfunction can generate large amounts of reactive oxygen species, exacerbating local oxidative stress in periodontal tissues and causing cell toxicity and tissue damage. Mitochondria are also the center of cellular inflammatory responses, and the positive feedback loop of inflammation induced by mitochondrial dysfunction may explain the persistent and unresolved nature of periodontitis. Biomaterials loaded with pharmacological agents show potential in restoring mitochondrial function, controlling the development of periodontitis, and promoting periodontal tissue regeneration. However, the key sites of mitochondrial dysfunction in the occurrence and development of periodontitis are not yet fully understood, and the improvement of mitochondrial function in periodontal therapy is still in the experimental stage. Future research efforts should focus on the effect of mitochondrial dysfunction on periodontal cells and explore its specific mechanism in the occurrence and progression of periodontitis in order to provide new insights into the treatment of periodontitis.

Objective To study the effect of artificial intelligence in the pathological diagnosis of periapical cysts and to explore the application of artificial intelligence in the field of oral pathology. Methods Pathological images of eighty-seven periapical cysts were selected as subjects to read, and a neural network with a U-net structure was constructed. The 87 HE images and labeled images of periapical cysts were divided into a training set (72 images) and a test set (15 images), which were used in the training model and test model, respectively. Finally, the target level index F1 score, pixel level index Dice coefficient and receiver operating characteristic (ROC) curve were used to evaluate the ability of the U-net model to recognize periapical cyst epithelium. Results The F1 score of the U-net network model for recognizing periapical cyst epithelium was 0.75, and the Dice index and the areas under the ROC curve were 0.685 and 0.878, respectively. Conclusion The U-net network model constructed by artificial intelligence has a good segmentation result in identifying periapical cyst epithelium, which can be preliminarily applied in the pathological diagnosis of periapical cysts and is expected to be gradually popularized in clinical practice after further verification with large samples.

Recurrent aphthous ulcer (RAU) is one of the most common diseases of the oral mucosa. At present, no effective method is available for RAU treatment, especially for refractory RAU, which significantly affects patients’ oral health and quality of life. Research shows that combination with systemic diseases greatly increases the difficulty of curing refractory RAU, making conventional oral ulcer treatment harder to perform effectively. This is probably because dentists commonly only focus on handling oral ulcers but neglect to think about the etiology of oral ulcers from a holistic perspective. Thus, we summarized some conditions of refractory RAU accompanied by systemic diseases, including inflammatory bowel disease, iron deficiency anemia, diabetes mellitus, Behçet’s disease, Reiter’s syndrome, sprue syndrome, Sutton syndrome, and acquired immunodeficiency syndrome. We also outlined the treatment principles of these patients. To be specific, on the one hand, dentists should cooperate with the relevant specialists to treat the systemic diseases, while on the other hand they should take measures including topical/general use of medicine, local physical therapy, Traditional Chinese medicine treatment, and psychotherapy for RAU management. This paper aims to provide clinicians with a more comprehensive understanding of the diagnosis and treatment of refractory RAU, in order to make personalized treatment plans for patients and improve the clinical efficacy of refractory RAU.

Objective To investigate the effect of micro/nano hierarchical structures on the adhesion and proliferation of MC3T3-E1 cells, evaluate the drug delivery potential of titanium surfaces, and provide a reference for the modification of selected areas of titanium surfaces to enhance drug delivery and slow drug release. Methods Pure titanium samples (10 mm in diameter and 2.5 mm in thickness) were randomly divided into a polished group (T), anodized group (TO), and micro/nano hierarchical structure group (FTO) according to the surface treatment of the titanium. The T group was polished, the TO group was treated with anodic oxidation technology, and the FTO group was treated by femtosecond laser etching combined with anodic oxidation technology. The three surface morphologies were observed by scanning electron microscopy (SEM), the wettability of the surface was measured by the contact angle, and the surface chemical composition was analyzed by X-ray energy dispersive spectroscopy (EDS). The depth of the FTO structure and the surface roughness were measured by confocal laser scanning microscopy (CLSM). MC3T3-E1 cell adhesion proliferation and differentiation on the surface of each group of samples was assessed by immunofluorescence staining, CCK-8, and semiquantitative analysis of Alizarin staining. A freeze-drying method was applied to load recombinant human bone morphogenetic protein-2 (rhBMP-2), and an enzyme-linked immunosorbent assay (ELISA) was used to assess the drug-loading potential of different surface structures. Results SEM revealed that the surface of T group titanium plates showed uniform polishing marks in the same direction. The surface of the TO group was a nanoscale honeycomb-like titanium dioxide (TiO₂) nanotube structure, and the FTO group formed a regular and ordered micro/nano layered structure. The contact angle of the FTO group was the smallest at 32° ± 1.7°. Its wettability was the best. The average depth of the first-level structure circular pores was 93.6 μm, and the roughness was 1.5-2 μm. The TO and FTO groups contained a high percentage of oxygen, suggesting TiO₂ nanotube formation. The FTO group had the most significant surface cell proliferation (P<0.001) and the largest cell adhesion surface area (P<0.05). rhBMP-2 was slowly released for 14 d after loading in the FTO group and promoted extracellular matrix mineralization (P<0.001). Conclusion Titanium surface microprepared hierarchical structure has the effect of promoting MC3T3-E1 cell adhesion, proliferation, and osteogenic differentiation with drug loading potential, which is a new method of titanium surface treatment.

Objective To analyze the current status, hotspots, and trends in the field of stem cell therapies for periodontal tissue engineering based on bibliometric analysis. Methods The literature on stem cell therapies for periodontal tissue engineering in animal experiments and clinical studies was searched in the Web of Science core database up to December 31, 2021. The bibliometric analysis of the relevant literature data was carried out by using the "Bibliometrix" package of R language. Results A total of 304 articles were included, and the number of publications and the citation frequency are increasing. The number of related studies from China ranks first in the world with 166 publications; the institution with the largest number of publications is the Fourth Military Medical University; the author with the largest number of publications is Jin Y; and Tissue Engineering Part A had the most related publications. The hotspots of stem cell therapies for periodontal tissue engineering are mainly focused on tissue engineering and periodontal ligament regeneration, while the frontiers are mainly focused on exosomes, gold nanoparticles, and angiogenesis. Conclusion Research on stem cell therapies for periodontal tissue engineering continues to expand, and the academic influence is gradually increasing. Future research directions should focus on periodontal ligament regeneration, exosomes, gold nanoparticles and angiogenesis.

Traditional titanium implants do not completely meet the clinical requirements because they are bioinert. The surface of titanium implants, modified by strontium ions, can enhance osseointegration and reduce peri-implantitis. In this paper, the biological properties of titanium implant surfaces modified by strontium ions were reviewed. Strontium ions can be coated on the implant surface by hydrothermal treatment, electrochemical deposition, phosphate chemical conversion, flame-spraying, supramolecular self-assembly, magnetron sputtering, laser deposition and alkali etching. Implant surfaces modified by strontium ions can not only promote osteogenesis and early osseointegration but also inhibit bacterial growth and reduce postoperative infections. Even better osseointegration and antibacterial effects can be achieved when strontium ions are incorporated with other elements, such as silver, zinc, gallium, and calcium. However, most of the studies on the use of strontium ion-modified titanium implants are animal experiments and in vitro experiments, and the observation time is short compared with the actual service life of the implants. Thus, the conclusions obtained may be different from the actual clinical application, and the long-term effects need to be studied. In addition, the osteogenic effects of various modification methods also need to be compared. Future research can focus on the following points: ① to find efficient modification methods that can be widely used in the clinic; ②to study how to control the concentration of strontium ions near the implant to exert their biological function and reduce their toxic side effects; and ③ to conduct long-term follow-up clinical trials to observe their osteogenic and antibacterial effects.

Free tissue flap transplantation is the preferred option for repairing and reconstructing postoperative defects in oral and maxillofacial-head malignant tumors. However, challenges remain for oral and maxillofacial-head and neck oncology surgeons in terms of ischemia-reperfusion (I/R) injury, airway management, quality of life and prognosis. I/R injury is an inevitable complication of free-flap transplantation surgery. In addition to shortening the vascular anastomosis time as much as possible during the surgical process, many studies have attempted to further prevent and treat free-flap I/R injury using physical intervention therapy, antioxidant and reactive oxygen species (ROS) scavenger therapy, hyperbaric oxygen therapy, etc. However, there is a lack of large-scale clinical randomized controlled trial evidence to further support these methods. Postoperative tracheal management of patients receiving free tissue flap transplantation is very important. In recent years, delayed extubation has been proposed as an alternative to traditional tracheostomy. This method can facilitate wound care for patients, reduce infections, speed up patient recovery, and reduce the incidence of vascular crises. In the future, such management is expected to improve the practicality and safety of delayed extubation by formulating more appropriate patient selection criteria and intensive care plans. Preoperative selection of suitable free tissue flaps according to the defect for repair and reconstruction is beneficial for improving the quality of life and survival rate of patients. At the same time, for patients who require postoperative radiotherapy, reducing the complications of postoperative radiotherapy and improving the quality of life of patients can be achieved through intraoperative nerve anastomosis, preradiation oral hygiene maintenance, early speech training, and other methods.

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.