Pulpal Disease Research Articles

Neural Regeneration in Regenerative Endodontic Treatment: An Overview and Current Trends

Pulpal and periapical diseases are the most common dental diseases. The traditional treatment is root canal therapy, which achieves satisfactory therapeutic outcomes-especially for mature permanent teeth. Apexification, pulpotomy, and pulp revascularization are common techniques used for immature permanent teeth to accelerate the development of the root. However, there are obstacles to achieving functional pulp regeneration. Recently, two methods have been proposed based on tissue engineering: stem cell transplantation, and cell homing. One of the goals of functional pulp regeneration is to achieve innervation. Nerves play a vital role in dentin formation, nutrition, sensation, and defense in the pulp. Successful neural regeneration faces tough challenges in both animal studies and clinical trials. Investigation of the regeneration and repair of the nerves in the pulp has become a serious undertaking. In this review, we summarize the current understanding of the key stem cells, signaling molecules, and biomaterials that could promote neural regeneration as part of pulp regeneration. We also discuss the challenges in preclinical or clinical neural regeneration applications to guide deep research in the future.

Factors that influence the outcome of pulpotomy in permanent teeth.

The promotion of minimally invasive treatments focussed on the maintenance of pulp vitality has become a priority area in Endodontics. These vital pulp treatments (VPT) include partial and full pulpotomy, during which diseased coronal pulp tissue is removed prior to placement of a capping biomaterial and restoration. Traditionally, pulpotomies were confined to the treatment of carious primary and traumatized permanent teeth. However, these treatments have now been proposed as definitive solutions for cariously exposed permanent teeth with mild symptoms or even symptoms indicative of irreversible disease. Until recently, it was recommended that carious exposure of mature permanent teeth be managed by root canal treatment. The promotion of pulpotomy as an alternative treatment has opened up a wave of laboratory and clinical research aimed at improving therapies or evaluating clinical outcomes. In modern evidence-based endodontics, it is imperative that the outcomes of both partial and full pulpotomy are considered and important prognostic factors identified, so that improvements can be made to aid clinical decision-making and to direct new research. In this narrative review, the outcomes of partial and full pulpotomy are discussed, before analysis of patient, intraoperative and postoperative factors that influence the outcome of the pulpotomy procedure. The review highlights that although partial and full pulpotomy for the treatment of even pulpal disease are highly successful procedures, this is based on low-quality evidence with a lack of prospective, comparative trials investigating potential prognostic factors. Based on current evidence, it appears that age, gender, tooth type, root development and intraoperative pulpal haemorrhage do not impact significantly on pulpotomy outcome, whilst others such as caries depth, inflammatory status of the pulp, capping material, level of inflammatory pulpal-biomarkers and the final restoration integrity do. Other factors, including the influence of exposure type, periodontal condition, pulpal lavage, magnification, operator experience, isolation of the operating field and type of pulpotomy, require further experimental investigation before definitive conclusions can be made relating to the success of the pulpotomy procedure. Finally, there is not only a need for future well-designed prospective research addressing these issues but also a widening of our understanding of outcome to include patient-reported as well as clinician-reported outcomes.

Evaluation of the transdentinal capability of the intrinsic antibacterial cetylpyridinium chloride/cholesterol sterosomes in vitro and in vivo.

Dentinal tubules serve as disease-causing channels for infiltration and penetration of bacteria and their by-products; which are regarded as the major driver of pathogenesis in pulpal inflammation and infection. In this study, we aimed to evaluate the transdentinal potential of nanoscale cetylpyridinium chloride/cholesterol (CPC/Chol) sterosomes, which are a recently developed type of cationic non-phospholipid liposomal nanocarrier; as well as their intrinsic and universal antibacterial activity. Cetylpyridinium chloride/cholesterol sterosomes were formulated, with a hydrodynamic diameter of 134 ± 4nm, a low polydisperse index of 0.161 ± 0.007, and a positive zeta potential of 41 ± 3mV at pH7.4. Transdentinal diffusion ability of sterosomes was evaluated using human dentine blocks in vitro, and Wistar rat molar teeth in vivo. The intrinsic antibacterial activities of CPC/Chol sterosomes against Enterococcus faecalis, Streptococcus mutans, Fusobacterium nucleatum, and Porphyromonas gingivalis were further examined. Cetylpyridinium chloride/cholesterol sterosomes successfully penetrated through the dentinal tubules, and diffused into the pulp, which could be internalized by dental pulp cells with a high efficiency. In addition, they exhibited substantial levels of intrinsic antibacterial activity against these Gram-positive and Gram-negative endodontic bacteria and their biofilms. Given its high penetration and diffusion ability through the dentine and pulp, great potential for multi-drug delivery, and distinct intrinsic antibacterial activity; sterosome-based nanocarriers might serve as a promising therapeutic strategy aimed at targeting various specific pathways associated with pulpal diseases. This will help determine and characterize the most appropriate prophylactic and therapeutic targets for early intervention in our future dentistry practice.

MicroRNA and their implications in dental pulp inflammation: current trends and future perspectives.

MicroRNAs (miRNAs) are short, 19-23 nucleotide non-coding RNA molecules that regulate gene expression by silencing or degrading the target mRNA gene. Since their discovery in the nineties of the last century, they have emerged as key inflammatory regulators. Inflammation induces the synthesis of various miRNAs that modulate the expression of multiple molecules involved in orchestrating the inflammatory response. This review aims to provide an insight into the role of miRNAs as potential biomarkers, mediators, and potential therapeutic targets of dental pulp inflammation. A literature search was conducted using the keywords; biogenesis of microRNA, human dental pulp cells, pulpitis, and inflammation in PubMed and Scopus index databases for all the published articles dealing with the role of miRNAs in pulp inflammation in the last 10years. According to the literature, there is a clear correlation between miRNAs and several physiological events, as well as their role as mediators of innate immune response and inflammation in dental pulp cells. Our narrative review stipulates that numerous miRNAs play a key role in modulating inflammation, delaying or enhancing cell repair, cell differentiation, and survival in dental pulp diseases. However, further studies are required for the validation of miRNAs as reliable biomarkers in dental pulp pathology and their targeted therapy.

The role of saliva in maintaining oral health: Aid to diagnose systemic ailments-A review

Saliva is a complex secretion from three major and various minor salivary glands present in mouth. From clinical point of view saliva is an ideal diagnostic fluid because it is non-invasive fluid and can be easily be collected from the patients for biochemical analysis. The other significant characteristic pertinent to saliva is the handling procedure which is much simpler in comparison with serum or blood. There is plethora of studies which shows a positive correlation between blood biomarkers and salivary biomarkers in different clinical conditions of oral and systemic diseases. Saliva has an important role in maintain oral health through variety of its secretions like calcium, phosphorus, Bacteriocins, salivary leukocyte protease inhibitors different enzymes like ptyalin, amylase for carbohydrate and protein metabolism which maintains tooth integrity when there is demineralization and also acts as first line defense against various bacterial and viral infections. In 21 century endodontic there is a paradigm shift in research on the change in composition of the saliva and biomarkers in presence of periodontal / pulpal and other systemic diseases. Molecular methods for identification and quantification of salivary biomarkers like IL-6, IL-8, MMPs are available at chair side for rapid diagnosis of various inflammatory or infective etiology of oral diseases.

Case Description of Oral Cavity Hard Tissue Disease in Banjarmasin 2017-2020

Disease that rank first from the list of ten major diseases that are often complained by Indonesian people is oral cavity diseases. The Hard Tissue of oral cavity lesions can be in the form od caries, periodontal disease, periapical abnormalities, cysts, and tumor in the oral cavity. Based on the Riset Kesehatan Dasar (Riskesdas) in 2018 the prevalence of dental and oral problem in Indonesia in South Kalimantan was 59,6%. The purpose of this study is to determine the description of oral hard tissue lesions in Banjarmasin city in 2017-2020. This research is descriptive study using a cross sectional approach. The variables on this study were oral hard tissue disease and gender, the data used were secondary data that obtained from the recording and reporting of the LB-1 form at Banjarmasin Community Health Center. The results showed that the most common type of disease on oral hard tissue case in 2017-2020 was pulp and periapical tissue disease, in 2017 it was 12,640 cases (78.37%), in 2018 it was 18,184 cases (51,45%). In 2019 it was 22,493 cases (57.07%) and in 2020 it was 3,220 cases (58.59%). In 2017, the most cases were in men with total of 7,887 cases (62.50%),while in 2018, 2019, and 2020, the most cases were in women with a total of 11,621 cases (64,29%), 14,285 cases (63.51%) and 1,892 cases (58.76%). It is necessary to prevent oral hard tissue disease, especially in pulp and periapical tissue disease.

Antibacterial activity of chrysophsin-3 against oral pathogens and Streptococcus mutans biofilms.

Dental caries and pulpal diseases are common oral bacterial infectious diseases, the prevention and treatment of these diseases require the control of the causative pathogens, such as Streptococcus mutans (S. mutans) and Enterococcus faecalis. As a cationic antimicrobial peptide, Chrysophsin-3 has broad-spectrum bactericidal activity against both Gram-positive and Gram-negative bacteria which may cause a variety of oral infectious diseases. The present study evaluated the potential of chrysophsin-3 against several oral pathogens and S.mutans biofilms. The cytotoxic activity of chrysophsin-3 against human gingival fibroblasts (HGFs) was investigated for potential oral application. We use minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and time-kill assay to evaluate the killing effect of chrysophsin-3. Then scanning electron microscopy (SEM) and Transmission Electron Microscope (TEM) were used to analyze the change of morphology and membrane of the pathogens, Live/Dead staining and confocal scanning laser microscopy (CSLM) was used to observe S. mutans biofilms. The results indicate that chrysophsin-3 has varying antimicrobial activities against different oral bacteria. Chrysophsin-3 did not cause obvious cytotoxicity in HGFs at concentrations of 32-128 μg/ml for 5 min or 8 μg/ml for 60 min. SEM revealed membranous blebs and pore formation on the bacterial cell surface, and TEM showed loss of the nucleoid and dissolution of the cytoplasmic space. Furthermore, the CSLM images indicate that chrysophsin-3 can reduce the viability of the cells within the biofilms significantly and had a comparatively lethal effect against S. mutans biofilms. Taken together, our finding suggests that chrysophsin-3 has potential clinical application in oral infectious disease, especially in preventing and treating dental caries.

Melatonin exerts anti-fibrinolytic effects by regulating IL-1β-induced changes in uPA, uPAR, and PAI-1 expression/production in human dental pulp cells

Interleukin-1b (IL-1β) is a pro-inflammatory cytokine and its expression is increased in inflamed dental pulp. IL-1β affects plasminogen activation system molecules, which are crucial for tissue inflammation, fibrinolysis, matrix turnover, and cell adhesion and migration. Melatonin, which provides circadian and seasonal signals, is a physiological endocrine generated by the pineal gland. It has anti-oxidant and anti-inflammatory properties. Studies are warranted to determine whether melatonin prevents IL-1β-induced expression/production of plasminogen system molecules. Human dental pulp cells (HDPCs) were exposed to IL-1β or melatonin alone or to IL-1β with/without pretreatment with melatonin or other inhibitors. The mRNA expression of uPA, uPAR, and PAI-1 was quantified using real-time polymerase chain reaction analysis. The cellular uPA, PAI-1, and soluble uPAR (suPAR) production was determined using an enzyme- linked immunosorbent assay. Signaling molecules’ protein expression was analyzed by immunofluorescent staining. We found that IL-1β (0.1–10 ng/mL) stimulated uPA and uPAR expression/production but inhibited PAI-1 expression/production of HDPCs. Melatonin inhibited uPA but stimulated uPAR/suPAR and PAI-1 expression/production. Intriguingly, melatonin prevented IL-1β-induced uPA mRNA expression/production. Conversely, melatonin enhanced the IL-1β-induced uPAR and PAI-1 mRNA expression/protein production of HDPCs. IL-1β-induced suPAR production was attenuated by U0126 (a MEK/ERK inhibitor), SB203580 (a p38 inhibitor), and 5Z- 7oxozeaenol (a TAK1 inhibitor), whereas SB203580 prevented an IL-1β-induced decline of PAI-1 production. Moreover, melatonin attenuated the IL-1b-induced p-ERK, p-p38, p-Akt and p-TAK1. These results revealed the crucial role of IL- 1β in the pathogenesis of pulpal inflammation/repair via stimulation of uPA and uPAR and inhibition of PAI-1, which can be differentially regulated by p38, Akt, MEK/ERK, and TAK1. Melatonin exerts an anti-fibrinolytic effect on IL-1β- induced changes in uPA, uPAR, and PAI-1 in HDPCs. Clinically, the melatonin levels of patients may affect pulpal inflammatory response. Melatonin and signal transduction inhibitors may be administered concomitantly for the prevention and treatment of pulpal inflammatory diseases

Profile of dental use for diseases of pulp and periapical tissues under the National Health Insurance system in Taiwan in 2020

Background/purposeThe penetration rate of National Health Insurance (NHI) of Taiwan is as high as 99.9%. This study investigated the profile of dental use for diseases of pulp and periapical tissues under the NHI system of Taiwan in 2020. Materials and methodsData on the population and medical records of the NHI system were obtained from the websites of Ministry of the Interior and the NHI Administration, respectively. The dental patient data were divided into 18 age groups to analyze dental treatment records claimed in 2020. ResultsUnder the NHI system in Taiwan in 2020, the dental use rate for treatment of diseases of pulp and periapical tissues had the highest peak (12.76%) in the 5–9-year age group. It dropped abruptly to the lowest point (2.71%) in the 10–14-year age group, raised gradually with increasing age, reached to the second and third highest peaks in the 70–74-year (10.75%) and 65–69-year (10.72%) age groups, respectively, and finally declined to 4.40% in the greater than 85-year age group. Furthermore, the number of out-patient visits per 1000 people and the medical expenses per person for diseases of pulp and periapical tissues among the same 18 age groups also showed a similar trend to the dental use rate. ConclusionDiseases of pulp and periapical tissues are still the main diseases of the oral cavity. From a cost-effectiveness viewpoint, Taiwan government should develop a better oral health care policy to prevent dental caries from deteriorating into diseases of pulp and periapical tissues for all citizens.

Ambiguity of lateral canals

For successful endodontic therapy, clinicians must have a thorough understanding of the complexities present in the root canal system such as accessory canals, lateral canals, furcal canals, and apical ramifications. It has been reported in the literature that lateral canals and/or apical canals are likely to be associated with pulp disease and canal reinfection. As a result, this emphasizes the importance of infection control not only in the main canal but also throughout the root canal system and its variations. The current article presents with an insight into the clinical aspects of lateral canals.

Endodontic Challenges in the Management of Multiple Pulp Stones and Root Canal Calcification - A Case Report

Root canal calcification is currently a challenging and interesting case for endodontists. Removing microorganisms and their by-products from the root canal system is the goal of root canal treatment. Worse outcomes from root canal procedures can occur due to root canal calcification, as it can block access to the root canal and hinder cleaning and shaping. Iatrogenic errors may occur in the treatment of such cases which will lead to failure of endodontic treatment. This case report describes a 20-year-old woman with multiple pulp stones in the pulp chamber of the mandibular left first molar. In addition, there were also calcified root canals in the mesiolingual and mesiobuccal canals. The patient had asymptomatic irreversible pulpitis and had to undergo endodontic treatment. Several challenges were faced in this case. The initial challenge was to determine the location of the pulp stone in the pulp chamber. Radiographs taken from multiple angles, as well as a direct assessment of the cavity during access preparation, addressed this initial challenge. Retrieval of the pulp stone which in this case is the embedded type that was carried out by grinding it with the help of an ultrasonic tip. Other difficult challenges were avoiding perforation of the pulp chamber floor during treatment, especially when removing the pulp stone, and identifying the location of the orifice. With clinical knowledge, magnification aids and ultrasonic tips, successful treatment in this challenging case was achieved.
 Calcific metamorphosis, sometimes known as pulp canal obliteration (PCO), is the extensive formation of tertiary dentin in the pulp chamber leading to circumferential narrowing of the pulp chamber and root canal.[1] According to the AAE (American Academy of Endodontics), PCO is radiographic evidence of increased dentin production mainly in response to trauma. The result is a calcified canal and does not necessarily indicate pulp disease.[2] Pulp calcification is a common occurrence. The incidence varies, but overall it can be estimated that 50 % of teeth have one or more calcifications.[3]
 There is no evidence to explain whether pulp calcification is a pathological process associated with various forms of injury or natural phenomena.[3] In general, the pulp chamber becomes progressively smaller and often very small, a phenomenon known as calcified metamorphosis or obliteration of the pulp canal. Dentin can be accelerated by caries, trauma, abrasion, restoration, and periodontal disease and is not uniform.[1]
 Calcifications are divided into denticle (pulp stones) and diffuse (linear) calcifications. Pulp stones are divided into free, attached, and embedded types. Pulp stones tend to be found in the coronal pulp, and diffuse calcifications are found in the radicular pulp. It has been speculated that the nidi of calcification arise from degenerating nerves or blood vessels, but this has not been proven.[1

Correlation between the beverage serving activities and the dental use of health care resources of National Health Insurance for common oral diseases

Background/purpose: Taiwanese get use to drinking hand-shaken beverages. However, excessive sugar intake is strongly associated with the occurrence of dental caries. This study evaluated the correlation between the beverage serving activities and the dental use of National Health Insurance (NHI) for common oral diseases in 2016. Materials and methodsData on the population, the beverage serving activities, and the dental records of NHI were obtained from the related websites of government. These data were divided by cities and counties to investigate the beverage serving activities and the dental use of NHI for common oral diseases in 2016. ResultsIn Taiwan, the value of beverage consumption per person had a moderate to high positive correlation with the dental use rate, the number of out-patient visits per 1,000 people, and the medical expenses per person for common oral diseases. For dental caries, diseases of pulp & periapical tissues, and gingivitis & periodontal diseases, their Pearson’s r values were 0.52–0.61, 0.18–0.40, and 0.58–0.65, respectively. These results indicate that the higher the beverage consumption per capita, the higher the dental use per capita. ConclusionThere is a long-term benefit for oral health and systemic health through reducing or avoiding unnecessary excessive sugar intake. Therefore, from a cost-effectiveness viewpoint, Taiwan government should develop a better oral health care policy including a health education strategy of appropriate sugar intake to prevent dental caries and other non-communicable diseases in Taiwanese people.

Effect of Epinephrine Combined with Articaine in the Treatment of Dental Pulp Diseases and Its Influence on Inflammatory Factors

Effect of Epinephrine Combined with Articaine in the Treatment of Dental Pulp Diseases and Its Influence on Inflammatory Factors

Failure of Regenerative Endodontic Procedures: Case Analysis and Subsequent Treatment Options

IntroductionRegenerative endodontic procedures (REPs) are considered effective treatments for immature necrotic permanent teeth, with favorable outcomes. However, failed cases require subsequent treatment. This study aimed to review and analyze failed cases after REPs and suggest a treatment algorithm to aid clinical decision-making. MethodsA total of 111 REP cases were selected that were conducted between 2015 and 2020. Clinical outcomes were assessed based on clinical and radiographic evaluations. The criteria for failure included persistence of clinical signs or symptoms and/or periapical radiolucency showing persistent apical periodontitis. Cases requiring any treatment intervention, including extraction, were also considered failures. ResultsSixteen cases were included as failures. The etiology of pulpal disease was stratified into dental trauma (56%), dens evaginatus (25%), and dental caries (12.5%), with the remaining one case having an undocumented cause. The primary reasons for treatment failure were persistent infection (81.3%) and root resorption (18.7%). The identification time of failure varied, with 6 cases (37.5%) detected in less than 6 months and 10 cases (62.5%) later than 6 months after REPs. Sixteen failed cases received 5 different interventions: second REPs, apexification, conventional root canal treatment, surgical approach, and extraction. ConclusionsInterventions for failed REPs are challenging. Consideration of the treatability of the tooth, accessibility to the canal, and the presence of an apical seat might be key factors in clinical decision-making to obtain a successful outcome.

Impact of Coronavirus Disease 2019 on Dental Service Utilization of Korean Children and Adolescents

This study aimed to investigate the frequency of dental visits after coronavirus disease 2019 (COVID-19) in children and adolescents in comparison to that of adults. The data on the number of dental visits on the basis of different classification and treatment codes for all the age groups were provided by the Health Insurance Review and Assessment Service from January 2017 to December 2020. To reduce the impact of the population change, dental visits per 1000 people was used. After the start of the pandemic, dental visits per 1000 people decreased in all age groups when analyzed for the diseases of pulp and periapical tissues classification code and dental visits per 1000 people decreased over 5 years age groups when analyzed for the pulp treatment code. Regarding the restorative treatment code, visits in the 0 - 19 years age group decreased after the pandemic. Based on the comparison of the number of confirmed COVID-19 cases to that of monthly dental visits by treatment codes, the change rate of pulp and restorative treatments gradually decreased after the waves of the pandemic in February and August 2020 in Korea. Furthermore, dental visits per 1000 people for gingivitis and periodontal disease classification code increased after the pandemic in all age groups. The rate of decrease in dental visits per 1000 people for restorative treatments in children and adolescents was higher than that in adults. The rate of decrease in the number of dental visits for multi-visit pulp treatments showed a rapid decrease as compared to that of 1-visit pulp treatments after the pandemic. This study identified changes in the number of dental visits of children and adolescents after COVID-19 transmission in comparison to that observed in adults.

Bioceramics in Vital Pulp Therapy

The goal of vital pulp therapy (VPT) is to protect and maintain the vitality of pulp ally involved teeth that have been compromised by pulpal diseases. Due to a greater understanding of pulp physiology and bio ceramic materials linked with adhesive technology, significant progress has been made in this field. The enhanced biological competence related to the high pH and long-term calcium release are the main features of bioceramics which are intended to improve the clinical outcome of pulp capping procedures. In this article, we would discuss bio ceramics and their role in improving clinical outcomes in vital pulp therapy. Keywords: Vital pulp therapy, bioceramics.

Endodontic management of pulp canal obliteration: A case report of two cases

Pulp canal obliteration (PCO) is defined as a deposition of hard tissue within the root canal space and a yellow discoloration of clinical crown. These tissues can eventually produce the radiographic appearance of a root canal space that has become partial or completely calcified. These teeth provide an endodontic treatment challenge. The critical management decision being whether to treat these teeth endodontically immediately upon detection of the pulpal obliteration or to wait until symptoms or signs of pulp or periapical disease occur. Success in root canal treatment is based on proper debridement, disinfection and obturation of the root canal system. However, this procedure may be difficult or even impossible to achieve if the pulpal space is calcified. The endodontic treatment performed under these circumstances pose the risk of root perforation, a complication that seriously affects the long-term prognosis of tooth. The present article discusses a series of cases of endodontic treatment in teeth with partially or completely PCO and methods for the clinical management of these cases using contemporary endodontic techniques.

Prescription Pattern of Antibiotics among General Dental Practitioners in Karnataka—A Cross-Sectional Survey

Abstract Introduction There is a lack of clear guidelines for the use of antibiotics and analgesics in medically healthy patients as well as endodontic pain management strategies. Diseases of the dental pulp and periapical tissue are mainly caused by microorganisms; however, not all cases of dental infections require the administration of systemic antibiotics. The purpose of the present survey was to evaluate the prescription pattern of antibiotics among general practitioners and specialists practicing in Karnataka. Methods This descriptive cross-sectional survey was based on a structured questionnaire in Google Form with 17 questions, including the demographic characteristics and the knowledge and practice of the dentists on the antibiotic prescription. Completed questionnaires were analyzed using the SPSS software to determine relationships between factors affecting the prescription patterns and educational qualification. Results Of the 200 participants surveyed, 169 (84.9%) felt that the overuse of antibiotics can lead to resistance of bacteria. Amoxicillin 500 mg was the most prescribed antibiotic (97%) and cephalexin by only 3% of the participants. Majority of the dentists prescribed antibiotics on a weekly basis (51.8%) during their practice and the preferred duration was for 5 days (62.8%). Conclusion The results of the present study indicated a lack of knowledge and uncertain diagnosis on prescribing antibiotics leading to overprescription and further antibiotic resistance. The majority of the dentist feels there is an overuse of antibiotics, but at the same time prescribes it on a daily basis.

Hypoxia‑induced mitophagy regulates proliferation, migration and odontoblastic differentiation of humandental pulp cells through FUN14 domain‑containing 1.

FUN14 domain-containing 1 (FUNDC1) is a receptor that has been previously reported to activate hypoxia-induced mitophagy. However, the potential role of FUNDC1 in the pathophysiology of dental pulp diseases remains unknown. Therefore, present study first collected tissue specimens from patients with pulpitis and from healthy individuals. The results of reverse transcription-quantitative PCR and immunohistochemical staining revealed markedly increased FUNDC1 and hypoxia-inducible factor-1α expression in pulpitis tissue specimens compared with those from healthy individuals. To provide a theoretical basis for the study of the occurrence, development and reparative mechanisms in the dental pulp after tissue injury, the present study then investigated the role of hypoxia-induced mitophagy in the regulation of proliferation, migration and odontoblastic differentiation in human dental pulp cells (HDPCs), in addition, to the possible involvement of FUNDC1. The surface markers and multipotent differentiation capabilities of HDPCs were performed by flow cytometry (surface markers), alizarin red (osteogenic capabilities), alcian blue (chondrogenic capabilities) and oil red O (adipogenic capabilities). Following culture under hypoxia conditions (1% O2) for varying time periods, the proliferation, migration and odontoblastic differentiation of HDPCs were measured using Cell Counting Kit-8, wound healing and Transwell migration assays, alkaline phosphatase staining and activity tests and western blotting (runt-related transcription factor 2, collagen I, osterix and osteopontin), respectively. Immunofluorescence and western blotting were performed to measure the expression levels of hypoxia-inducible factor-1α, pro-fission dynamin-related protein 1, mitochondria-related proteins translocase of inner mitochondrial membrane 23 and translocase of outer mitochondrial membrane 20, in addition to those of autophagy markers (p62, LC3II, Beclin-1 and autophagy-related 5). Transmission electron microscopy was also used to image the autophagosomes and mitochondrial morphology. In addition, to study the functional role of FUNDC1, its expression was silenced by liposome-mediated transfection with small interfering RNA into HDPCs. Compared with those in HDPCs cultured under normoxic conditions (21% O2), the ability of autophagy in HDPCs cultured under hypoxic conditions for 18 h was markedly increased, whilst the proliferation, migration and odontoblastic differentiation were also enhanced. Increased numbers of autophagosomes could also be observed in the hypoxic group. However, FUNDC1 knockdown in HDPCs reversed the aforementioned effects. Overall, data from the present study suggest that hypoxia can promote the proliferation, migration and odontoblastic differentiation of HDPCs, where the underlying mechanism may be associated with the activation of mitophagy downstream of FUNDC1.

Overview of technical advances in the diagnosis of pulp and periapical diseases

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