Introduction: Regeneration of pulp tissue after infection is complicated and has frequently failed because current methods cannot control inflammation or eliminate bacterial infection. Numerous studies have demonstrated the effects of flavonoids on regeneration. Scrophularia is an exceptional plant source rich in flavonoids, and many flavonoid compounds have been extracted from it. This study aimed to determine the effects of Scrophularia striata and adipose tissue-derived stem cells on the expression of Kruppel-like factor 4 (KLF4), monocyte chemoattractant protein-1 (MCP-1), and brain-derived neurotrophic factor (BDNF) genes during pulp tissue regeneration in an animal model. Method: This experimental-laboratory study was conducted on 16 male Wistar rats. The methanolic extract of Scrophularia striata was prepared by maceration (Scro). Adipose tissue was harvested from the bilateral inguinal region of rats that did not undergo surgery, and adipose-derived stem cells (SC) were isolated and characterized. Pulp inflammation was induced in the rats, and pulpectomy was performed at the end of the second week. After placement of a triple-antibiotic paste for 2 weeks, regenerative treatment with drugs and materials was performed. Three weeks after tooth filling, the teeth were randomly divided into four groups (n = 4/group): (1) control (blood clot only), (2) Scrophularia alone (Scro), (3) stem cells alone (SC), and (4) Scrophularia + stem cells (SC+Scro). One to four weeks after tooth filling, the dental pulp was harvested from the animals. Real-time PCR was used to measure the expression levels of KLF4, MCP-1, and BDNF genes. Data were analyzed using one-way ANOVA and Tukey's test (alpha = 0.05). Result: Injection of Scro, SC, and SC+Scro significantly increased KLF4 gene expression compared with the control group (P = 0.001). The highest level of KLF4 expression was observed in the SC group (P = 0.001), which was significantly reduced in the SC+Scro group compared with the SC group (P = 0.001). Injection of Scro significantly decreased MCP-1 gene expression compared with the control group (P = 0.001). Injection of SC did not significantly alter MCP-1 expression compared with the control group; however, injection of SC+Scro significantly increased MCP-1 expression compared with all other groups (P = 0.001). Injection of Scro, SC, and SC+Scro significantly increased BDNF gene expression compared with the control group (P = 0.001). The highest BDNF expression was observed in the Scro group (P = 0.001), which was significantly reduced in the SC+Scro group compared with the Scro and SC groups (P = 0.001). Conclusion : The results of this study showed that application of the Scro extract increased the expression of KLF4 and BDNF genes and decreased MCP-1 expression. Application of the Scro+SC combination increased the expression of KLF4, BDNF, and MCP-1 genes. Application of adipose-derived stem cells increased the expression of KLF4 and BDNF genes, with no significant effect on MCP-1. According to this study, the plant extract enhanced the expression of dentinogenesis-related factors during pulp regeneration.

This study evaluated the mechanical and biological performance of a zinc-modified bioactive glass-resin pulp-capping agent (NPA) under clinically relevant conditions and compared it with MTA Angelus and Biodentine in the presence of blood and phosphate-buffered saline (PBS). Setting time (n = 4; ISO 9917) and Vickers microhardness (n = 10) were measured after exposure to blood- or PBS-moistened pellets. Dental pulp stem cell (DPSC) adhesion (n = 6) was examined by scanning electron microscopy, and DPSC migration (n = 6) was assessed using a scratch assay with material extracts diluted at 1:1, 1:4, and 1:8. The results showed that blood exposure significantly prolonged setting times for all materials (p < 0.05), with NPA showing the longest and Biodentine the shortest. NPA demonstrated the highest microhardness in both media (p < 0.01), although blood reduced hardness across groups. At 1:1 dilution, no measurable cell migration was observed; therefore, statistical analysis was limited to diluted concentrations. Lower concentrations enhanced cell migration, reaching 124% for MTA, 104.5% for NPA, and 86% for Biodentine at 1:8. SEM confirmed DPSC adhesion on all materials, with improved spreading on MTA and NPA. Despite slower setting, NPA showed superior microhardness and favorable cellular responses, suggesting its potential as a candidate material for vital pulp therapy.

Dental anomalies can be challenging for clinicians to diagnose and treat, such as fusion/gemination, which can be considered one of the most challenging anomalies to present a treatment plan for, due to esthetic, orthodontic, and periodontal problems they can cause in most cases. This case report describes an 8-year-old patient who complained of the unpleasant appearance of her right central incisor. Oral and radiographic examinations revealed a supernumerary tooth unilaterally fusing with the maxillary permanent central incisor. Two major factors in choosing a treatment plan in this case included: patient's age and presence of anomaly in the esthetic zone. This case report describes a treatment approach involving endodontic, periodontal, and restorative interventions for preserving a tooth in a child who could not undergo routine treatments such as implant placement due to incomplete growth of her dentoalveolar region, and bone deficiency caused by the dental anomaly.

Background: Information about root canal anatomical variations is important for successful root canal treatment. This study assessed the frequency of common anomalies of permanent mandibular first and second molars using cone-beam computed tomography (CBCT). Methods: In this cross-sectional study, 505 CBCT scans were evaluated by an oral radiologist and an endodontist to determine the presence/absence of the mid-mesial canal, the C-shaped canal configuration and its type, the third root and its type, taurodontism and its percentage, and dilaceration and its degree. To assess intra- and inter-observer agreements, all CBCT scans were evaluated twice at a one-week interval by both observers. The data were analyzed using the kappa coefficient and univariate logistic regression. Results: The kappa values showed acceptable inter-observer (0.780) and intra-observer (0.983) agreements. Of all, 21 teeth (4.17%) had a mid-mesial canal, 20 teeth (3.96%) had a third root, and 38 teeth (7.52%) had a C-shaped canal. The frequency of the third root (P=0.01) and C-shaped canal (P<0.000) in mandibular second molars was significantly higher than that in mandibular first molars (P<0.000). Taurodontism was detected in 6 teeth (1.19%), while root dilaceration was present in 162 teeth (34.23%). Age and gender had no significant association with the presence of a mid-mesial canal, third root, C-shaped canal, or dilaceration (P>0.05). Conclusion: Mandibular first and second molars were not significantly different in the frequency of mid-mesial canal, taurodontism, and dilaceration. Considering the relatively high prevalence of dilaceration and C-shaped canals in the study population, these anatomical variations should be taken into account in root canal treatment.

The addition of zinc oxide (ZnO) to mineral trioxide aggregate (MTA) has been shown to prevent tooth discoloration; however, its biological effects remain unclear. This study aimed to evaluate the pulpal responses to MTA containing 5% ZnO in full pulpotomy of dogs’ teeth. Forty caries-free premolars from mixed-breed dogs were subjected to full pulpotomy. Exposed pulpal tissues were randomly capped with either Angelus MTA (MTA) or Angelus MTA mixed with 5% ZnO (MTA + ZnO) (n = 20 each). After 4 weeks, the teeth were extracted, processed for histological evaluation, and stained with hematoxylin and eosin. Tissue response data were analyzed using the Mann-Whitney U test at a 95% significance level. The incidence, thickness, and continuity of hard-tissue bridge formation were significantly lower in the MTA + ZnO group (p = 0.007, p = 0.001, and p = 0.002, respectively). Most samples in both groups exhibited no inflammatory cells, and none showed signs of necrosis. Incorporating ZnO into Angelus MTA compromised the quantity and quality of hard-tissue bridge formation following full pulpotomy in dogs’ premolars.

OBJECTIVES:This study aimed to compare the effects of different laser-activated irrigation (LAI) methods on apical extrusion of indocyanine green (ICG). MATERIALS AND METHODS:In this in vitro study, 40 extracted single-canal premolars were instrumented and randomly assigned to 4 groups (n = 10) of (I) ICG (1 mg/mL) + photon-induced photoacoustic streaming (PIPS) with 2940 nm erbium laser, 20 mJ energy, and 50 µs pulse width for 30 s, (II) ICG + shockwave enhanced emission photoacoustic streaming (SWEEPS) with 2940 nm erbium laser with 20 mJ energy, and 50 µs pulse width (two 25 µs pulse widths) for 30 s, (III) ICG + 810 nm diode laser with 250 mW power for 30 s, and (IV) ICG without activation. Photoluminescence (PL) was used to quantify the ICG volume extruded through the apex, and determine the excitation wavelength of the ICG samples. To calibrate the PL results, one random ICG sample underwent inductively-coupled plasma (ICP) test to quantify the sulfur content of the extruded ICG. Considering the chemical formulation of ICG, the concentration of extruded ICG was calculated accordingly. Data were analyzed by one-way ANOVA (alpha=0.05). RESULTS:The best spectrum was obtained at 390 nm excitation wavelength with 700 V voltage and slit number=10. The study groups had no significant difference in the concentration of apically extruded ICG (P = 0.611). CONCLUSION:The tested LAI protocols had no significant difference with each other or with the no activation protocol regarding the apical extrusion of ICG.

Key Clinical MessageSuccessful management of a rare case involving both dens evaginatus and dens invaginatus in the same tooth, monitored over a 24‐month follow‐up.AbstractDens invaginatus (DI) is a congenital dental anomaly characterized by the presence of a tooth that resembles a “tooth within a tooth.” Conversely, dens evaginatus (DE) is a developmental anomaly distinguished by an additional tubercle or cusp on the tooth's crown. Both DI and DE can result in pulpal and periapical diseases in the affected tooth. This article presents a case of a healthy 14‐year‐old male with recurrent swelling under the chin and a wound with pus drainage on the right side of the submental area, associated with his left mandibular lateral incisor affected by both DI and DE. Clinical and radiographic examinations revealed that the tooth was necrotic and had a chronic apical abscess. Cone beam computed tomography (CBCT) confirmed Oehlers' type III DI and a talon cusp on the lingual surface of the same tooth. The patient underwent orthograde endodontic treatment. Passive ultrasonic activation of a 5.25% NaOCl solution and a mixture of Ca(OH)2 and a 2% chlorhexidine solution were utilized to effectively clean and eliminate the persistent pus discharge. After the resolution of the patient's symptoms, the apical third of the root canal and the invaginated space were filled with a plug of mineral trioxide aggregate (MTA), while the remaining root canal was filled using a sealer‐based obturation technique. A 24‐month follow‐up visit revealed complete bone regeneration in the previously affected periradicular tissues.

Background and Aim: Artificial Intelligence (AI) models, such as Convolutional Neural Networks (CNNs) and Artificial Neural Networks (ANNs), are increasingly being utilized to analyze Cone Beam Computed Tomography (CBCT) images. This comprehensive review aims to explore the diagnostic and prognostic accuracy of AI when applied to CBCT imaging in endodontic practices, highlighting its potential to enhance clinical outcomes. Materials and Methods: A comprehensive electronic literature search was conducted using prominent electronic databases, including Google Scholar, PubMed, Medline, and Scopus. The search strategy spanned publications from 2000 to the present, employing targeted keywords such as "AI", "machine learning", "deep learning", "endodontics", "CBCT", "advanced analytics", "computational linguistics", "automation", "intelligent agents", "probabilistic reasoning", "CNN", and "ANN". Results: The initial search identified a total of 2072 articles, of which 37 met the stringent inclusion criteria for this review. The analysis revealed a significant concentration of research on key areas within endodontics, including the verification of working lengths, detection and projection of periapical pathologies, assessment of root canal morphologies, and predictions related to root fractures. Recent studies emphasize the growing focus on improving the precision and efficiency of endodontic diagnostics through AI-powered CBCT applications. Conclusion: The findings of this review underscore the pivotal role that AI-enhanced CBCT imaging plays in advancing diagnostic accuracy and improving prognostic evaluations in endodontics. The integration of AI with CBCT heralds a new era of precision in endodontic care, facilitating more efficient workflows and standardized diagnostic practices while reducing the potential for human error.

Background Several efforts have been made to improve mechanical and biological properties of calcium silicate-based cements through changes in chemical composition of the materials. This study aimed to investigate the physical (including setting time and compressive strength) and chemical (including calcium ion release, pH level) properties as well as changes in cytotoxicity of mineral trioxide aggregate (MTA) after the addition of 3 substances including CaCl 2 , Na 2 HPO 4 , and propylene glycol (PG). Methods The systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Electronic searches were performed on PubMed, Embase, and Scopus databases, spanning from 1993 to October 2023 in addition to manual searches. Relevant laboratory studies were included. The quality of the included studies was assessed using modified ARRIVE criteria. Meta-analyses were performed by RevMan statistical software. Results From the total of 267 studies, 24 articles were included in this review. The results of the meta-analysis indicated that addition of PG increased final setting time and Ca 2+ ion release. Addition of Na 2 HPO 4 did not change pH and cytotoxicity but reduced the final setting time. Incorporation of 5% CaCl 2 reduced the setting time but did not alter the cytotoxicity of the cement. However, addition of 10% CaCl 2 reduced cell viability, setting time, and compressive strength. Conclusion Inclusion of 2.5% wt. Na2HPO4 and 5% CaCl2 in MTA can be advisable for enhancing the physical, chemical, and cytotoxic characteristics of the admixture. Conversely, caution is advised against incorporating elevated concentrations of PG due to its retarding effect. Trial registration PROSPERO registration number: CRD42021253707.

Background: Addition of zinc oxide (ZnO) to mineral trioxide aggregate (MTA) has been shown to overcome the problem of tooth discoloration; however, the biological effects of ZnO addition have not been elucidated. The aim of this study was to evaluate the pulpal responses to MTA containing 5% ZnO when used in full pulpotomy in dogs’ teeth. Methods: Forty caries-free premolars were selected from mixed-breed dogs and were subjected to full pulpotomy. The exposed pulpal tissues were randomly capped with either Angelus MTA (MTA) or Angelus MTA mixed with 5% ZnO (MTA+ZnO) (n = 20 each). After 4 weeks, the teeth were extracted and processed for histological evaluation and stained with hematoxylin and eosin. Data related to tissue response were analyzed by the Mann-Whitney U test with a significance level of 95%. Results: The incidence, thickness and continuity of hard-tissue bridge formation was significantly lower for the MTA+ZnO (p = 0.007, p =0 .001 and p=0.002, respectively). In both experimental groups, most samples exhibited no inflammatory cells. None of the samples in either group demonstrated necrosis. Conclusions:Incorporation of ZnO into Angelus MTA compromised the quantity and quality of hard-tissue bridge formation observed subsequent to full pulpotomy in dogs’ premolars.

Key Clinical Message Management of supernumerary teeth fused to the labial surface of permanent maxillary central incisors would require a multidisciplinary approach comprising of endodontic treatment, periodontal recontouring, and cosmetic composite restoration. Abstract The reported cases of supernumerary teeth fused to the labial surface of maxillary central incisors are rare. Such cases need multidisciplinary approaches. Herein, management of a supernumerary tooth fused to the labial surface of a maxillary central incisor is reported. Due to the presence of a communication path between the root canal systems of the two fused teeth, root canal therapy was performed first for the maxillary left central incisor and the supernumerary tooth. The crown of the supernumerary tooth was then removed in a surgical setting while preserving the root to maintain the thin covering of alveolar bone and prevent future periodontal problems. Subsequently, an esthetic composite restoration was performed.

Objectives:This study aimed to assess the effect of addition of fluorohydroxyapatite (FHI) on biological and physical properties of mineral trioxide aggregate (MTA) Angelus.Materials and Methods:In this in vitro, experimental study, nano-FHI powder was first synthesized, and the morphology and chemical structure of particles were evaluated by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Three groups were evaluated in this study: MTA Angelus, MTA modified with 10% FHA, and MTA modified with 15% FHA. After mixing, the materials were applied to ring molds (10 mm diameter, 1 mm height), and the setting time of the three groups was evaluated according to ISO6876 and ASTMC266-03 with a Gillmore needle. The pH was measured using a pH meter at 24 and 48 hours and 7 days after mixing. The cytotoxicity of the materials was assessed in freshly mixed form and after 1 and 7 days using the methyl thiazolyl tetrazolium (MTT) assay according to ISO10993-5. Data were analyzed by one-way and repeated measures ANOVA and Tukey's test (alpha = 0.05).Results:The addition of FHA to MTA significantly decreased the initial setting time (P < 0.05) and had no significant effect on cell viability (compared with pure MTA Angelus) at 1 and 7 days. However, modified MTA groups in freshly mixed form showed significantly lower cell viability (P < 0.05). The pH remained alkaline at all time points.Conclusion:Addition of 15% FHA to MTA Angelus decreased its setting time with no adverse effect on cell viability (except for fresh form) or pH.

Aim: The aim of this study is to measure and compare the amount of apical extrusion of the methylene blue as photosensitizer using Laser-activated irrigation(LAI) techniques (SWEEPS, PIPS) and photodynamic therapy (PDT).Materials and methods: 40 single-rooted premolar teeth were selected and their root canals were cleaned and prepared. The photosensitizer, Methylene blue (MB), was used as dye which applied inside the root canals and the access cavities. Then the teeth were randomly allocated to 4 groups. Different techniques (SWEEPS, PIPS, PDT) were used in 3 groups. One group received no activation. Data related to the concentration of the extruded methylene blue was measured using ultraviolet and visible (UV-Vis) absorption spectroscopy. Absorption peak intensity of MB in the wavelength of 668 nm was considered as the concentration index according to Beer Lambert law. Taking into account the normal distribution of this data, one-way ANOVA analysis was used to evaluate the effects of the independent variables on the amount of apical extrusion of the irrigant.Results: Based on the results of ANOVA analysis, there was no significant difference between the amounts of apical extrusion of MB between different groups (p = 0.628)Conclusion: Using SWEEPS and PIPS techniques, despite diffusion of the photosensitizer, didn't lead to any dif-ference in the amount of apical extrusion. Therefore, these LAI techniques can be used safely for root canal irrigation.

BACKGROUND AND AIM:Regenerative endodontic procedures (REPs) are oriented by the principles of tissue engineering, incorporating dental pulp stem cells (DPSC), crucial growth factors like Transforming growth factor-β (TGF-β1), and scaffolds to facilitate the regeneration of dental pulp tissues. The present study aimed to investigate the effect of photobiomodulation (PBM) therapy, using an 808 nm diode laser on cellular modulation mechanisms in REPs. METHOD AND MATERIAL:A total of 108 human dentin discs obtained from intact single root teeth were randomly assigned into six groups (n = 8): 1. Positive control (EDTA), 2. PBM-1 (3 J/cm2), 3. PBM-2 (5 J/cm2), 4. EDTA+PBM-1, 5. EDTA+PBM-2, and 6. Negative control (NaOCl). Then, an extract solution was prepared from each disc and the concentration of released TGF-β1 from the discs was measured using enzyme-linked immunosorbent assay (ELISA). Moreover, the extract solution was added to DPSC culture medium to evaluate cell viability and migration through MTT assay and scratch test, respectively. RESULT:The group exposed to PBM-1 showed the highest cell viability, while treatment with EDTA and EDTA+PBM-2 decreased cellular viability. Also, the PBM-treated groups showed significantly higher release of TGF-β1 compared to the negative control. EDTA and EDTA+PBM-1 showed the highest release among all the groups. No significant difference was found between EDTA and EDTA+PBM-1, as well as between PBM-1 and PBM-2. Moreover, the PBM-1 group exhibited the highest migration after 24 h, which was significantly greater than other groups, except for the PBM-2 group. CONCLUSION:According to the obtained data, 808 nm mediated-PBM (3 J/cm2), both independently and in conjunction with EDTA, enhanced the release of TGF-β1 from dentin and improved cell viability and migration of DPSCs. It seems that, PBM under the specific parameters employed in this study, could be an effective adjunctive therapy in REPs.

This study aimed to synthesize and characterize a novel dental pulp capping cement containing bioactive glass (BG)/zinc oxide modified with an organic resin. BG (45S5) with or without ZnO (Zn) and hemaphosphate (HP) combined with a liquid consisting of polyacrylic and itaconic acids (AA) were synthesized and the structural, physical, and mechanical properties were assessed. Hydroxyapatite formation was evaluated by immersion in simulated body fluid. Biological analysis including methyl thiazolyl tetrazolium assay, alizarin red staining, alkaline phosphatase (ALP) activity, and gene expression of odontogenic markers were performed to evaluate the cytotoxic effect and biomineralization potential of the cements on human dental pulp stem cells (hDPSCs). A commercial mineral trioxide aggregate (MTA) served as control. The highest compressive strength value and the shortest setting time were belonged to the BG + HP + AA and BG + AA groups, respectively. The shear bond strength to dentin was the highest for the BG + HP + AA cement. Scanning electron microscope showed only scarce deposits of calcium phosphate formation on the surface of the synthesized cements. BG + HP + AA and BG + HP + Zn + AA groups had significantly lower cytotoxicity than MTA. The mineralization potential of hDPSCs after stimulation by the novel cements increased. Quantitative reverse-transcription-polymerase chain reaction showed higher odontogenic marker expression in hDPSCs exposed to the BG + HP + Zn + AA cement compared to other synthesized cements, although it was higher in MTA group. Based on the obtained results, the novel synthesized cements can be used as appropriate capping agents in the treatment of dental pulp.

Key clinical message A successful management of an advanced external cervical resorption using a conservative approach with CBCT, dental operating microscope, and a new bio‐ceramic material. Abstract External cervical resorption (ECR) is a pathologic condition that is initiated on the external aspect of the root, below the epithelial attachment in the cervical position. This article will report a case of external cervical resorption (ESR) in an advanced stage, which was asymptomatic and was incidentally detected in a follow‐up radiograph after the end of orthodontic treatment. Cone‐beam computed tomography (CBCT) was prescribed to accurately diagnose the resorptive lesion and differentiate it from internal root resorption (IRR), and the final diagnosis was Heithersay's class IV ECR. Considering the health of the periodontium and the absence of attachment loss, it was decided to use a conservative internal approach to the management of this case. After the treatment, the patient was asymptomatic and the radiographic examinations showed no signs of peri‐radicular pathology during the follow‐up period. With the correct case selection and the availability of the appropriate materials and equipment such as a dental operating microscope (DOM) and bio‐ceramic materials, the internal approach can be a successful and minimally invasive treatment, even for the management of advanced ECR cases.

Revitalizing the root canals of previously treated teeth with open apices is appealing to clinicians and patients. However, there are fundamental differences in the microbiome and the microenvironment between a canal with a primary endodontic infection and a canal with a persistent endodontic infection. The aims of this report are to report a case where a previously treated tooth with an open apex and a large apical radiolucency was treated successfully using regenerative endodontic treatment (RET), and to review and critically appraise the literature on procedures and outcomes of RET that results in revitalization of canal(s) in previously treated teeth with open apices. A maxillary central incisor with poor quality root filling, a large apical radiolucency and an open apex was retreated using RET using platelet-rich fibrin as the scaffold. After 24 months, there was complete healing of the periapical lesion and obvious radiographic signs of apical root closure. Electronic searches were performed in MEDLINE, Scopus and Embase and the baseline, procedural and outcome data of qualified articles were collected. An assessment tool was developed to rate the quality of evidence reported in these case report/series. Nine articles, three case series and six case reports, with a total of 17 teeth of all types were included in the reports identified. The age of patients ranged from 7-48 years (mean: 19.4 years). The recall period ranged from 12-72 months (mean: 29 months). All 17 teeth survived and were functional with healing/healed outcomes. "Apical closure" was the most common radiographic finding regarding root development. The quality of evidence using the new assessment tool was rated "Excellent" in three case reports but only "Fair" in the other six articles. The present case report as well as the review of the literature suggest that revitalizing the root canal system of teeth with open apices and post-treatment disease using RET is a potentially valid treatment option. However, more clinical studies with higher levels of evidence and higher quality of evidence are required to confirm the viability of this treatment approach.

Revitalizing the root canals of previously treated teeth with open apices is appealing to clinicians and patients. However, there are fundamental differences in the microbiome and the microenvironment between a canal with a primary endodontic infection and a canal with a persistent endodontic infection. The aims of this report are to report a case where a previously treated tooth with an open apex and a large apical radiolucency was treated successfully using regenerative endodontic treatment (RET) and to review and critically appraise the literature on procedures and outcomes of RET that result in revitalization of canal(s) in previously treated teeth with open apices. A maxillary central incisor with poor-quality root filling, a large apical radiolucency and an open apex was retreated using RET using platelet-rich fibrin as the scaffold. After 24 months, there was complete healing of the periapical lesion and obvious radiographic signs of apical root closure. Electronic searches were performed in MEDLINE, Scopus and Embase, and the baseline, procedural and outcome data of qualified articles were collected. An assessment tool was developed to rate the quality of evidence reported in these case report/series. Nine articles, three case series and six case reports, with a total of 17 teeth of all types, were included in the reports identified. The age of patients ranged from 7 to 48 years (mean: 19.4 years). The recall period ranged from 12 to 72 months (mean: 29 months). All 17 teeth survived and were functional with healing/healed outcomes. "Apical closure" was the most common radiographic finding regarding root development. The quality of evidence using the new assessment tool was rated "Excellent" in three case reports but only "Fair" in the other six articles. The present case report, as well as the review of the literature, suggests that revitalizing the root canal system of teeth with open apices and post-treatment disease using RET is a potentially valid treatment option. However, more clinical studies with higher levels of evidence and higher quality of evidence are required to confirm the viability of this treatment approach.

Revitalizing the root canals of previously treated teeth with open apices is appealing to clinicians and patients. However, there are fundamental differences in the microbiome and the microenvironment between a canal with a primary endodontic infection and a canal with a persistent endodontic infection. The aims of this report are to report a case where a previously treated tooth with an open apex and a large apical radiolucency was treated successfully using regenerative endodontic treatment (RET) and to review and critically appraise the literature on procedures and outcomes of RET that result in revitalization of canal(s) in previously treated teeth with open apices. A maxillary central incisor with poor-quality root filling, a large apical radiolucency and an open apex was retreated using RET using platelet-rich fibrin as the scaffold. After 24 months, there was complete healing of the periapical lesion and obvious radiographic signs of apical root closure. Electronic searches were performed in MEDLINE, Scopus and Embase, and the baseline, procedural and outcome data of qualified articles were collected. An assessment tool was developed to rate the quality of evidence reported in these case report/series. Nine articles, three case series and six case reports, with a total of 17 teeth of all types, were included in the reports identified. The age of patients ranged from 7 to 48 years (mean: 19.4 years). The recall period ranged from 12 to 72 months (mean: 29 months). All 17 teeth survived and were functional with healing/healed outcomes. “Apical closure” was the most common radiographic finding regarding root development. The quality of evidence using the new assessment tool was rated “Excellent” in three case reports but only “Fair” in the other six articles. The present case report, as well as the review of the literature, suggests that revitalizing the root canal system of teeth with open apices and post-treatment disease using RET is a potentially valid treatment option. However, more clinical studies with higher levels of evidence and higher quality of evidence are required to confirm the viability of this treatment approach.