Search

Background: Regenerative endodontic therapy (RET) is still coming up short to demonstrate histological evidence for true regeneration with clinically feasible protocol of cell homing in single visit approach., Aim: The aim of the present study is to evaluate the regenerative potential of photobiomodulation (PBM) on RET in immature roots when photodynamic therapy (PDT) protocol is implemented for root canal disinfection in canine model., Materials and Methods: Seventy-two root canals were recruited, with sixty assigned to experimental groups and twelve to positive and negative controls. Following the induction of pulp necrosis and apical periodontitis, the roots were divided into two experimental groups: Group I received RET followed by PBM (seven sessions with an 808 nm diode laser at 300 mW for 90 s), and Group II received RET without PBM. Follow-ups were conducted at 1, 2, and 3 months (subgroups A, B, and C respectively). Qualitative and quantitative assessment was carried out histologically. All data were statistically analyzed with the Mann-Whitney U test and Bonferroni's adjustment, as well as Chi square test., Results: The newly formed hard tissue highly resembled true dentine where the dentinal tubules looked well organized lined by poly layers palisading pattern of rounded odontoblast-like cells with cytoplasmic processes extending through the predentine layer. GI exhibited statistically significantly higher scores of vital tissue infiltration and hard tissue deposition in subgroups A and B (P ≤ 0.05). The inflammatory cells scores were significantly lower in GI than in GII at all time intervals. However, no significance could be detected regarding apical closure., Conclusion: The disinfection protocol of PDT and subsequent irradiation with low power laser in PBM protocol pose a promising potential for regenerative endodontics in immature teeth., Competing Interests: Declarations. Ethics approval: The study at hand was reviewed and the ethical approval was obtained from the research ethics committee at the Faculty of Dental Medicine for Girls, Al-Azhar University under approval number REC-EN-21-09. Additionally, the protocol was registered in preclinicaltrial.eu with the registration number: PCTE0000162. Consent for application: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: Bioceramic-based root canal sealers are increasingly important in root canal treatment because of their biocompatible properties. This study aimed to evaluate postobturation pain incidence and intensity after root canal obturation with NeoSealer Flo, MTA-Bioseal, and GuttaFlow bioseal calcium silicate-based sealers and AH Plus epoxy resin-based sealer in patients with asymptomatic irreversible pulpitis or necrotic pulp with chronic apical periodontitis., Methods: A total of 120 participants with single-rooted teeth were included and randomly divided into four groups according to the root canal sealer used (n = 30). The patients were subsequently categorised based on the pulp vitality (vital or nonvital) in each group (n = 15) and all teeth were obturated in a single-visit. The postobturation pain scores were recorded on a visual analogue scale (VAS) at 6 h, 24 h, 48 h, 72 h, 7 d and 30 d. Moreover, analgesic intake was also noted at 24 h and 48 h. The Mann-Whitney U test, Kruskal‒Wallis H test, Friedman test, and Spearman's correlation test were used, and a p value < 0.05 was considered significant., Results: VAS scores were highest for the 6 h > 24 h > 48 h ≈ 72 h ≈ 7 d ≈ 30 d time intervals for both pulp status in each root canal sealer. A significant decrease in the VAS score was observed for all sealers from 6 h to 48 h (p 0.05). Nonvital cases had lower VAS scores at all time intervals. Analgesic intake was greater in the first 24 h (p < 0.05) in vital cases (p < 0.05) and also in females than males., Conclusion: The level of pain experienced after obturation was similar in patients with different pulp status for all the root canal sealers. Analgesic intake was greater in vital cases and females within 24 h., Trial Registration: ClinicalTrial.gov , NCT06515756, record date: 2024-07-17, retrospectively registered., Competing Interests: Declarations Ethics approval and consent to participate The study was approved and numbered (01.06.2023-07/06) by the Ethical Committee of the University of Kirikkale. and was registered under the protocol ID NCT06515756 (https://clinicaltrials.gov/) according to the CONSORT statement of the updated guidelines for reporting randomized clinical trials. Informed consent was taken from all participants. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Background: Regenerative endodontic procedures (REPs) offer the promise of restoring vitality and function to a previously necrotic and infected tooth. However, the nature of regenerated tissues following REPs remains unpredictable and uncontrollable. Decellularized extracellular matrix scaffolds have gained recent attention as scaffolds for regenerative endodontics., Objectives: Preparation and characterization of a bovine dental pulp-derived extracellular matrix (P-ECM) hydrogel for regenerative endodontic applications. Biocompatibility and regenerative capacity of the prepared scaffold were evaluated in vivo in a canine animal model., Methods: Fifteen freshly extracted bovine molar teeth were used to prepare P-ECM hydrogels following approval of the institutional review board of the faculty of dentistry, Alexandria University. Decellularization and lyophilization of the extracted pulp tissues, DNA quantification and histological examination of decellularized P-ECM were done. P-ECM hydrogel was prepared by digestion of decellularized pulps. Prepared scaffolds were evaluated for protein content and release as well as release of VEGF, bFGF, TGF-β1 and BMP2 using ELISA. Rabbit dental pulp stem cells' (rDPSCs) viability in response to P-ECM hydrogels was performed. Finally, proof-of-concept of the regenerative capacity of P-ECM scaffolds was assessed in an infected mature canine tooth model following REPs versus blood clot (BC), injectable platelet-rich fibrin (i-PRF) or hyaluronic acid (HA). Statistical analysis was done using independent t test, the Friedman test and chi-square tests (p value ≤ 0.05)., Results: DNA was found to be below the cut-off point (50 ng/mg tissue). Histological evaluation revealed absence of nuclei, retention of glycosaminoglycans (GAGs) and collagen content, respectively. P-ECM hydrogel had a total protein content of (493.12 µg/µl) and protein release was detected up to 14 days. P-ECM hydrogel also retained VEGF, bFGF, TGF-β1 and BMP2. P-ECM hydrogel maintained the viability of rDPSCs as compared to cells cultured under control conditions. P-ECM hydrogel triggered more organized tissues compared to BC, i-PRF and HA when used in REPs for necrotic mature teeth in dogs. Periapical inflammation was significantly less in HA and P-ECM groups compared to blood-derived scaffolds., Conclusion: Bovine dental pulp-derived extracellular matrix (P-ECM) hydrogel scaffold retained its bioactive properties and demonstrated a promising potential in regenerative endodontic procedures compared to conventional blood-derived scaffolds., (© 2024. The Author(s).)

Purpose: To evaluate the outcome of apexification using bioceramics in immature permanent teeth, and to study the factors influencing treatment outcome and frequency of spontaneous cervical root fractures., Methods: Forty-six children with 51 non-vital permanent incisors treated with a bioceramic apical plug were included. Mean age at pulp necrosis was 9.8 (SD 2.2) years and mean follow-up time was 3.3 (SD 2.4) years. Data were extracted from dental records and included stage of root development, presence of external root resorptions, clinical signs of infection, size of periapical lesion, type and placement of bioceramic plug, and spontaneous root fracture. Treatment outcome was assessed using periapical index (PAI-score) and presence of clinical symptoms. The statistical analyses were conducted using IBM SPSS Statistics for Windows, version 28 (IBM Corp., Armonk, N.Y., USA). Data were cross-tabulated and tested with chi-square statistic., Results: Biodentine™ was used as apical plug in 78.4% of the teeth and MTA in 21.6%. Complete healing or signs of healing was reported in 86.3% of the teeth, whilst seven teeth (13.7%) were non-healed. All non-healed teeth had preoperative clinical signs of infection. No difference was found in stage of root development, presence of root resorption, and type and placement of bioceramic plug in healed and non-healed teeth (p > 0.05). Five teeth (9.8%) exhibited root fracture 1-6 years after treatment and all had very immature root development. Type of bioceramic or external root resorption was not associated with spontaneous root fracture., Conclusion: Apexification using bioceramics showed favourable prognosis in immature permanent teeth. Very immature teeth were at risk of root fracture after apexification with bioceramics., (© 2024. The Author(s).)

Introduction: This prospective study evaluated the effect of immediate functional loading (IFL) of a full-coverage prosthesis on the clinical and radiographic outcome of nonsurgical endodontic therapy (NSET) performed on mandibular molar teeth with pulp necrosis and asymptomatic apical periodontitis., Methods: In 20 subjects, standardized 2-visit NSET was performed in bilateral mandibular first molar teeth (split-mouth model) with a diagnosis of pulp necrosis and asymptomatic apical periodontitis exhibiting a radiographic periapical index (PAI) score ≥3. In each subject, the nonvital bilateral mandibular first molar teeth were randomized to 1 of 2 groups: the IFL group or the functional loading after a time interval of 6 months group. Provisional full-coverage prostheses were provided within 7 days after the completion of endodontic therapy. The cases were followed up clinically and radiographically at 6 and 12 months. Radiographs were assessed for periapical healing based on PAI scores, which were dichotomized as healed (PAI score ≤2) or nonhealed (PAI score ≥3). The data were compared using chi-square and Fisher exact tests., Results: A recall rate of 100% was achieved at the end of 12 months. All teeth in the IFL group and the functional loading after a time interval of 6 months group were clinically asymptomatic. According to an intergroup comparison between the proportion of teeth healed and nonhealed (radiographic), there was a significant difference (P < .05)., Conclusions: IFL of a full-coverage prosthesis in endodontically treated mandibular molar teeth with pulp necrosis and asymptomatic apical periodontitis delayed periapical healing., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Regenerative endodontic procedures (REPs) are frequently utilized to treat immature permanent teeth with necrotic or inflamed pulps. In most instances, these treatments successfully result in the resolution of apical periodontitis and continued root maturation. However, after reviewing over 180 REP cases treated in the Endodontics Department of Stomatology Hospital at Zhejiang University School of Medicine over the past seven years, we identified an unusual root development pattern in ten cases, characterized by root tips detached from the root body. We conducted a comprehensive analysis of the patients' demographic information, dental histories, and therapeutic efficacy, and identified five potential etiological factors for this rare phenomenon, including external force, prolonged extensive periapical inflammation, iatrogenic factors, traumatic history of primary teeth, and excessive tooth mobility. In our study, we observed that therapeutic failure was more likely in patients with initially separated root tips, while those with initially normal teeth demonstrated significantly better prognoses. We hypothesize that the initial root condition may exert a considerable influence on treatment outcomes., Competing Interests: The authors declare no conflict of interest., (©2024 The Author(s). Published by MRE Press.)

Purpose: The aim of this study was to investigate the potential for pulp revascularization in relation to patient age at the time of injury following luxation injury of mature anterior permanent teeth., Materials and Methods: A total of 93 teeth from 70 patients were included. The patients were divided into subgroups based on their age at the time of the injury., Statistics: the Aalen-Johansen method was used to estimate the risks of pulp canal obliteration (PCO) and pulp necrosis (PN). The absolute 2 year risks of PCO and PN were obtained with cause-specific Cox regression and reported separately for each cohort, standardised to age at injury and degree of repositioning., Results: For the group younger than 15 years of age, the risk of PN after 12 months was 62.3% [95% CI 44.9; 79.7] in the cohort from 1972 to 1980 and 28.6% [95% CI 4.9; 52.2] in the cohort from 2012 to 2020. For the age group 16-20 years, the risk of PN after 12 months was 66.7 [95% CI 40.0;93.3] in the cohort from 1972 to 1980 and 25% [95% CI 0.0;55.0] in the cohort from 2012 to 2020. For the age group between 21 and 25, the risk of PN after 12 months was 66.7% [95% CI 40.0; 93.3] in the cohort from 1972 to 1980 and 55.6% [95% CI 23.1; 88.0] in the cohort from 2012 to 2020., Conclusion: There is potential for pulp revascularization in mature anterior teeth with lateral luxation in patients up to 25 years of age. The risk of PN appears to increase with age., Competing Interests: Declarations Conflict of interest All authors declare no conflicts of interest., (© 2024. The Author(s).)

Primary dental treatments for odontogenic sinusitis (ODS) due to endodontic infections (pulpal necrosis and apical periodontitis ± periapical abscess) include extraction and root canal treatment (RCT). Published evidence is lacking on the success of primary endodontic treatment for purulent ODS, with the majority of RCT-related series reporting on its success at resolving reactive maxillary sinus mucositis. Dental extraction is the most definitive treatment of endodontic disease causing ODS, but compromises the functional dentition and still often fails to resolve the purulent sinusitis. This article highlights key concepts of RCT and dental extraction techniques, as well as their published success at resolving ODS., Competing Interests: Disclosure J.R. Craig: research consultant for Aerin Medical, Inc., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Pulp necrosis is the most common complication following dental trauma and is often associated with apical periodontitis. The management of these teeth is challenging in terms of large root canals, open apices, thin dentinal walls, and short roots. Over decades the conventional treatment for these teeth was calcium hydroxide apexification, a time-consuming procedure despite high success rates. Subsequently after the introduction of mineral trioxide aggregate and hydraulic calcium silicate materials single visit apical plug procedures became increasingly practiced with comparable success rates to the conventional apexification. The search continued afterward for a clinical procedure that may stimulate further root development and apical closure to avoid the long-term complication of root fracture after apexification. Regenerative procedures using stem cells derived from the apical papilla and blood clots as scaffolds were then introduced for the management of immature teeth, with variable protocols and success rates. This review will cover the evidence available and current position of regenerative endodontic procedures in traumatized immature teeth with apical periodontitis, in terms of clinical protocols, outcome, and potential prognostic factors., (© 2024 The Author(s). Dental Traumatology published by John Wiley & Sons Ltd.)

This is a series of 7 cases in which the operator penetrated lateral canals with instruments. Two teeth presented with irreversible pulpitis, 4 with necrotic pulps, and 1 with previous treatment. Except for the teeth with pulpitis, all the others were associated with apical periodontitis. The main root canal was always relatively straight, with the lateral canals at the middle third of the root. Suggestive images of lateral canal presence were seen on periapical radiographs in five cases. The clinician introduced intentionally small hand instruments in the lateral canal in 5 cases, while the penetration was fortuitous in the others. The lateral canals were obturated in all cases. Follow-up examination was possible in five cases, all of them showed evidence of successful clinical and radiographic outcomes. Introducing files into lateral canals may permit some preparation and penetration of irrigant solution, favoring disinfection and, consequently, enhancing the treatment outcome. (EEJ-2023-05-063).

Background: Regenerative endodontic procedures (REPs) are innovative treatments aimed at restoring damaged dental structures. However, the effect of orthodontic movement on REP-treated teeth is not well understood and may have significant long-term consequences. This study aimed to evaluate the impact of orthodontic movement on a mature permanent tooth associated with dens invaginatus that has undergone a regenerative endodontic procedure (REP)., Case Presentation: This report describes the case of a 13-year-old healthy male who presented with pulp necrosis and a chronic apical abscess (tooth number 2.2). Following REP according to the American Association of Endodontists' guidelines, the patient began non-extraction orthodontic treatment with fixed appliances after a 9-month healing period, which lasted 17 months in the upper arch. Subsequent follow-ups at 24, 36 and 48 months post-REP revealed an asymptomatic state with minimal cervical discoloration and diminished cold sensitivity. Radiographic analyses revealed periapical healing, mild apical remodeling on tooth 2.2, and moderate apical remodeling on other maxillary incisors. The treated tooth displayed a positive response to both REP and orthodontic treatment, yet further research is required to determine the long-term effects of orthodontics on REP-treated teeth., Conclusion: Orthodontic movement following REPs in mature permanent teeth is feasible and do not seem to prone teeth to orthodontic tooth resorption. Our experience indicates that a 9-month healing period allows successful orthodontic outcomes following REPs. Nonetheless, the predictability of outcomes and the ideal healing period before orthodontic movement is initiated remain to be established., (© 2024. The Author(s).)

Background: This study aimed to evaluate whether the use of 8.25% sodium hypochlorite (NaOCl), compared with the use of 2.5% NaOCl, leads to higher postoperative pain after endodontic treatment., Methods: A total of 154 patients were randomly assigned into 2 groups: 8.25% and 2.5% NaOCl. A single-visit endodontic treatment was performed using a standard protocol, varying only the NaOCl concentration. Postoperative pain was assessed using the numeric rating scale at multiple times over 30 days. Overall pain scores over time were explored via multilevel mixed-effects negative binomial regression. The need for pain medication was recorded and compared between groups via the Mann-Whitney U test., Results: The use of 8.25% NaOCl increased postoperative pain scores over time by 3.48 times compared with the use of 2.5% NaOCl (incident rate ratio [IRR], 3.48; 95% CI, 1.57 to 7.67). Furthermore, the 8.25% NaOCl group exhibited higher pain incidence than the 2.5% NaOCl group during the 12-hour through 3-day period, with scores at these times ranging from 2.21 (IRR, 2.21; 95% CI, 1.35 to 3.62) through 10.74 (IRR, 10.74; 95% CI, 3.74 to 30.87) higher. No difference was detected in the number of analgesic capsules administered between groups., Conclusions: The use of 8.25% NaOCl resulted in higher postoperative pain than the use of 2.5% NaOCl, with pain scores increasing by 3.48 times when this solution was used. Furthermore, the 8.25% NaOCl group exhibited higher pain incidence than the 2.5% NaOCl group during the 12-hour through 3-day period., Practical Implications: The use of 8.25% NaOCl during endodontic treatment can increase postoperative pain significantly. This clinical trial was registered at the Brazilian Registry of Clinical Trials database (RBR-6vq3hc4)., Competing Interests: Disclosures None of the authors reported any disclosures., (Copyright © 2024 American Dental Association. Published by Elsevier Inc. All rights reserved.)

This review article describes the methods and clinical recommendations for reinforcing traumatized anterior immature teeth with pulp necrosis treated with mineral trioxide aggregate (MTA) apexification. Traumatic injury can cause pulp necrosis and incomplete root formation in immature teeth. MTA apexification is the treatment of choice for necrotic immature teeth, particularly during the middle or late stages of root development. MTA apexification has a high success rate; however, failures due to cervical or root fractures occasionally occur. The risk of fracture is higher in immature teeth with thin root dentin, particularly those with external root resorption. Furthermore, the loading force from any parafunctional habit also increases fracture risk. Therefore, intra-radicular reinforcement may be necessary after MTA apexification. In vitro, intraradicular restoration with a resin composite/core build-up material or a prefabricated fiber post demonstrated better root reinforcement than root canal obturation materials (i.e., gutta-percha and sealer). However, the root-reinforcement effect of MTA orthograde filling in the entire root canal remains unclear. In vivo, the survival of fractured teeth with intraradicular restorations (resin composite/core build-up material or prefabricated fiber posts) is extremely high. Moreover, the survival of teeth with gutta-percha/sealer obturation or MTA orthograde filling and restoration with resin composite extending into the cervical third of the root canal approximately 1-2 mm below the cemento-enamel junction is acceptably high. Based on this evidence, the remaining tooth/root structure and loading force should be carefully examined when considering intra-radicular reinforcement of immature anterior teeth treated with MTA apexification., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: To evaluate histologically and radiographically the potential of dog's immature roots with apical periodontitis to regenerate after regenerative endodontic treatment using mesoporous silica nanoparticles (MSNs) with/without bone morphogenic protein (BMP-2) as scaffolds., Methods: In 4 mongrel dogs, 56 immature teeth with 96 roots were infected, resulting in necrotic pulps and periapical pathosis. According to the evaluation time (Group I = 30 days and Group II = 90 days), 90 roots were divided into two equal groups (45 roots each) and 6 roots used to replace any lost root during the procedure. The two main groups were further divided according to treatment protocol into 5 subgroups (9 roots each): blood clot (BC subgroup), mesoporous silica nanoparticles scaffold only (MSNs subgroup), mesoporous silica nanoparticles impregnated with BMP2 (MSNs + BMP2 subgroup), infected teeth without treatment (+ ve control subgroup) and normal untouched teeth (-ve control subgroup). All teeth surfaces were coated with Tincture iodine and calcium hydroxide was applied prior to treatment protocols. Then, teeth were restored with glass ionomer filling to seal the remaining part of the access cavity. Radiography evaluation of the increase in root length, root thickness and occurrence of apical closure were performed. Following the sacrifice of the two dogs at each time of evaluation, histopathological analysis was performed and included the inflammatory cells count, bone resorption, tissue ingrowth, deposition of hard tissue, and closure of the apical part. All data were statistically analyzed., Results: Compared to BC subgroup, MSNs and MSNs + BMP-2 subgroups exhibited significant higher increase in root length and thickness as well as higher vital tissue in-growth and new hard tissue formation in group II (P < 0.05). MSNs + BMP-2 subgroup had significant higher increase in root length and thickness as well as significant lower inflammatory cell count than MSNs subgroup in both groups (P < 0.05). There were no significant differences between MSNs and MSNs + BMP-2 subgroups regarding new hard tissue formation in both groups and apical closure in group I (P > 0.05)., Conclusion: MSNs with/without BMP-2 scaffolds enabled the continuing growth of roots in immature teeth with necrotic pulps and periapical pathosis. Addition of BMP-2 to MSNs scaffold improved its outcome in regenerative endodontics., Clinical Relevance: MSNs with/without BMP-2 scaffolds may alternate blood clot for regenerative endodontic treatment of immature teeth with necrotic pulps., (© 2024. The Author(s).)

Objectives: To evaluate treatment outcomes of the apical barrier technique with premixed calcium silicate-based putty for treating necrotic permanent teeth with open apices and to identify prognostic factors., Materials and Methods: Permanent teeth with necrotic pulps and open apices treated by the apical barrier technique with premixed calcium silicate-based putty, with a minimum follow-up of 12 months, were included. Treatment outcomes were based on clinical signs, symptoms, and radiographic evaluation. The treatment outcome was dichotomized into success or failure according to strict and loose criteria. The chi-square test (or Fisher's exact test) and multiple logistic regression analysis were used to evaluate possible prognostic factors associated with treatment outcomes., Results: Seventy-four teeth with a follow-up time of 12-72 months (mean, 25.74 ± 14.36 months) were included in the final evaluation. The success rate was 97.30% using the loose criteria and 66.22% using the strict criteria. Multiple logistic regression analysis indicated that the size of pre-operative periapical lesion (≥ 5 mm) (odds ratio [OR]: 18.96; P = 0.0153) and root canal underfilling (OR: 8.341; P = 0.0448) were significant predictors for treatment failure under the strict criteria., Conclusion: The apical barrier technique with premixed calcium silicate-based putty is a highly successful procedure for treating necrotic permanent teeth with open apices after an observation period of up to 6 years. Treatment success under the strict criteria is primarily affected by the size of the pre-operative periapical lesion and the apical extent of root-filling., Clinical Relevance: Careful case selection and ensuring adequate root filling quality are essential to the successful outcome of the apical barrier technique with premixed calcium silicate-based putty., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Aim: To analyse the effect of ultrasonic irrigant activation (UIA) and the GentleWave (GW) multisonic irrigation (GW) with minimal instrumentation on the root canal microbial diversity in an ex vivo model that used extracted molars with a history of pulp necrosis., Methodology: Twenty-three mandibular molars were prepared ex vivo for collection of superficial (surface control), pre-treatment and post-treatment samples 24 h after extraction. Samples were divided into two groups: UIA using 6% NaOCl (n = 11) and GW group (n = 12). All samples were processed using quantitative real-time polymerase chain reaction (qPCR) and 16S rRNA next-generation sequencing to measure microbial diversity before and after the antimicrobial treatment. For qPCR, a t-test (α = .05) was used to compare the log10 reduction. The Chao1 and Shannon indices evaluated alpha diversity. Differences in community composition (beta diversity) were evaluated by analysis of similarity (ANOSIM). Kruskal-Wallis test with Bonferroni corrections was performed to evaluate the differences in abundances genera in the samples., Results: Quantitative real-time polymerase chain reaction revealed an estimated 1.6 and 2.6 log10 reduction for UIA and GW groups respectively (p = .048). An average of 5 ± 4 and 3 ± 5 operational taxonomic units (OTUs) were found in surface's samples in the UIA and GW group respectively. These values were significantly lower (p < .001) compared to the number of preoperative OTUs in those groups (155 ± 79 and 187 ± 121). In assessing beta diversity, there were no significant differences found in pre-treatment samples (R = .090, p = .070 ANOSIM with Bonferroni corrections). Also, no significant differences in community composition were observed in post-treatment samples (R = -.05, p = .829). After treatment, there was a significant reduction of Eubacterium using conventional treatment with UIA and a significant reduction of Prevotella using minimal instrumentation with GW irrigation (p = .007 and p = .002 respectively)., Conclusion: Quantitative PCR analysis revealed a significant reduction in microbial load for GW group. Overall, diversity changes were similar between UIA and GW irrigation in this ex vivo model that used extracted teeth with a history of pulp necrosis. OTUs obtained from the surface sample were negligible and did not affect the statistical outcome of the study., (© 2023 The Authors. International Endodontic Journal published by John Wiley & Sons Ltd on behalf of British Endodontic Society.)

Introduction: Regional odontodysplasia (ROD) is a rare developmental disorder characterized by hypo-mineralization and hypoplasia of enamel and dentin. Symptoms include poorly developed tooth buds, delayed eruption of permanent teeth in affected quadrants, and ghost teeth. The affected teeth often become necrotic due to abnormal enamel and dentin development, making them susceptible to caries and infection. The aim of this case report is to describe the treatment of ROD through pulp revascularization., Case Report: A 13-year-old girl was referred for endodontic treatment. The mandibular left incisors and first premolar, which were affected by regional odontodysplasia, lost their vitality because of the impaired structure of the enamel. Due to the teeth's early developmental stage, a regenerative endodontic treatment was attempted. All 3 teeth were treated using the same protocol following the AAE guidelines. After 4 weeks, treatment of the premolar was completed, whereas the incisor teeth remained symptomatic and were and therefore, intracanal dressing with calcium hydroxide was repeated and left in place for 5 months. Finally, the regenerative procedure was completed, and the crowns were restored. The patient was scheduled for follow-up examinations after 6 months, and then yearly for the next 3 years. After 1 year, the periapical lesion around the central incisor and premolar had resolved, the lesion around the apex of the lateral incisor was healing, and the roots had continued to develop. After 3 years, complete healing and pulp canal obliteration were observed in the central incisor and in the premolar. However, the root of the lateral incisor tooth was split, and it was recommended to extract this tooth., Conclusion: The positive outcomes of regenerative endodontics in the central incisor and premolar suggest that revascularization of the pulp may be optional for the treatment of immature necrotic teeth affected by developmental disorders, such as ROD, amelogenesis imperfecta, or dentinogenesis imperfecta., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: With the introduction of stem cell engineering in dentistry, regenerative endodontics has emerged as a potential alternative to mineral trioxide aggregate (MTA) apexification in the management of necrotic immature permanent teeth. However, the utility of this modality in terms of cost-effectiveness has not yet been established. Therefore, we performed cost-effectiveness analysis to determine the dominant treatment modality that would influence decision making from the private payer perspective., Methods: A Markov model was constructed with a necrotic immature permanent tooth in a 7-y-old patient, followed over the lifetime using TreeAge Pro Healthcare 2022. Transition probabilities were estimated based on the existing literature. Costs were estimated based on United States health care, and cost-effectiveness was determined using Monte Carlo microsimulations. The model was validated internally by sensitivity analyses, and face validation was performed by an experienced endodontist and health economist., Results: In the base-case scenario, regenerative endodontics did not turn out to be a dominant treatment option as it was associated with an additional cost of USD$1,012 and fewer retained tooth-years (15.48 y). Likewise, in the probabilistic sensitivity analysis, regenerative endodontics was again dominated by apexification against different willingness-to-pay values., Conclusion: Based on current evidence, regenerative endodontic treatment was not cost-effective compared with apexification in the management of necrotic immature permanent teeth over an individual's lifetime., Knowledge Transfer Statement: The study provides valuable insight regarding the cost valuation and cost-efficacy of regenerative endodontic treatment versus apexification in the management of necrotic immature permanent teeth, as this would aid in effective clinical decision making, allowing for the functional allocation of resources., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The dental pulp is the only soft tissue structure within the tooth, serving functions such as sensation and nutrition. However, the dental pulp is highly susceptible to necrosis due to external factors. Currently, root canal therapy is the most commonly used treatment for pulp necrosis. Nevertheless, teeth treated with root canal therapy are prone to secondary infections and adverse outcomes like vertical root fractures. Regenerative endodontic therapy has emerged as a solution, aiming to replace damaged tooth structures, including dentin, root structure, and the pulp-dentin complex cells. This approach demonstrates significant advantages in addressing clinical symptoms and achieving regeneration of the root and even the pulp. Since the discovery of dental pulp stem cells, regenerative endodontic therapy has gained new momentum. Advances in cell transplantation and cell homing techniques have rapidly developed, showing promising potential for clinical applications.

BACKGROUND The regenerative endodontic procedure (REP) for managing necrotic immature permanent teeth has the advantage of promoting root growth over the traditionally used apexification techniques. However, there is limited evidence on the long-term outcome of standardized REPs performed on immature molars. This case report presents the 5-year clinical and radiographic outcomes of REP performed on an immature mandibular first molar. CASE REPORT A healthy 7-year-old girl with a carious right mandibular first molar was referred to the endodontic clinic for evaluation and treatment. Clinical examination showed large occlusal caries, no tenderness to palpation and percussion tests, and no response to cold and electric pulp tests. Radiographic examination showed deep caries, apical radiolucency related to the open apices, and wide root canal space. Accordingly, the tooth was diagnosed with necrotic pulp and asymptomatic apical periodontitis. The REP was performed following the American Association of Endodontics guidelines, which comprise minimal instrumentation, disinfection with sodium hypochlorite irrigant, use of triple antibiotic paste, induced intracanal bleeding, and application of a coronal mineral trioxide aggregate plug. The patient missed the scheduled follow-up appointments but presented at the clinic 5 years later with an asymptomatic tooth. Clinical and radiographic examination revealed no tenderness to percussion and palpation test, no response to cold test, positive response to electric pulp test, apical healing, apical closure, root lengthening, and canal wall thickening and calcification. CONCLUSIONS While true pulp regeneration is unachievable, the REP, following the current protocol, is clinically successful in achieving root maturation and tooth retention.

Pre-eruptive intracoronal radiolucency is a rare dental anomaly with unclear aetiology, generally asymptomatic and diagnosed through routine radiographs. Failure to diagnose and treat it early can lead to rapid pulp damage, potentially compromising root development. The presented clinical report describes a mandibular second premolar with pre-eruptive intracoronal radiolucency that caused early pulp necrosis with arrest of root formation and emphasises the endodontic management using regenerative endodontic therapy.

Objective: The objectives of this study were to isolate, characterize progenitor cells from blood in the root canals of necrotic immature permanent teeth evoked from periapical tissues and evaluate the applicable potential of these isolated cells in Regenerative Endodontics., Design: Ten necrotic immature permanent teeth from seven patients were included. Evoked bleeding from periapical tissues was induced after chemical instrumentation of the root canals. Cells were isolated from the canal blood and evaluated for cell surface marker expression, multilineage differentiation potential, proliferation ability, and target protein expression. Cell sheets formed from these cells were transferred into human root segments, and then transplanted into nude mice. Histological examination was performed after eight weeks. Data analysis was conducted using one-way ANOVA followed by Tukey's post-hoc comparison, considering p < 0.05 as statistically significant., Results: The isolated cells exhibited characteristics typical of fibroblastic cells with colony-forming efficiency, and displayed Ki67 positivity and robust proliferation. Flow cytometry data demonstrated that at passage 3, these cells were positive for CD73, CD90, CD105, CD146, and negative for CD34 and CD45. Vimentin expression indicated a mesenchymal origin. Under differentiation media specific differentiation media, the cells demonstrated osteogenic, adipogenic, and chondrogenic differentiation potential. Subcutaneous root canals with cell sheets of isolated cells in nude mice showed the formation of pulp-like tissues., Conclusions: This study confirmed the presence of progenitor cells in root canals following evoked bleeding from periapical tissues of necrotic immature teeth. Isolated cells exhibited similar immunophenotype and regenerative potential with dental mesenchymal stromal cells in regenerative endodontic therapy., Competing Interests: Declaration of Competing Interest The authors deny any conflicts of interest., (Copyright © 2024. Published by Elsevier Ltd.)

Background: Immature teeth with necrotic pulps present multiple challenges to clinicians. In such cases, regenerative endodontic procedures (REPs) may be a favorable strategy. Cells, biomaterial scaffolds, and signaling molecules are three key elements of REPs. Autologous human dental pulp cells (hDPCs) play an important role in pulp regeneration. In addition, autologous platelet concentrates (APCs) have recently been demonstrated as effective biomaterial scaffolds in regenerative dentistry, whereas the latest generation of APCs-concentrated growth factor (CGF), especially liquid phase CGF (LPCGF)-has rarely been reported in REPs., Case Presentation: A 31-year-old woman presented to our clinic with the chief complaint of occlusion discomfort in the left mandibular posterior region for the past 5 years. Tooth #35 showed no pulp vitality and had a periodontal lesion, and radiographic examination revealed that the tooth exhibited extensive periapical radiolucency with an immature apex and thin dentin walls. REP was implemented via transplantation of autologous hDPCs with the aid of LPCGF. The periodontal lesion was managed with simultaneous periodontal surgery. After the treatment, the tooth was free of any clinical symptoms and showed positive results in thermal and electric pulp tests at 6- and 12-month follow-ups. At 12-month follow-up, radiographic evidence and three-dimensional models, which were reconstructed using Mimics software based on cone-beam computed tomography, synergistically confirmed bone augmentation and continued root development, indicating complete disappearance of the periapical radiolucency, slight lengthening of the root, evident thickening of the canal walls, and closure of the apex., Conclusion: hDPCs combined with LPCGF represents an innovative and effective strategy for cell-based regenerative endodontics., (© 2024. The Author(s).)

To explore a new method to implant deciduous tooth pulp into the canal of young permanent teeth with necrotic pulps and apical periodontitis for the regenerative endodontic treatment of tooth no: 41 in a 7-year-old male. Briefly, 1.5% Sodium Hypochlorite (NaOCl) irrigation and calcium hydroxide-iodoform paste were used as root canal disinfectant at the first visit. After 2 weeks, the intracanal medication was removed, and the root canal was slowly rinsed with 17% Ethylene Diamine Tetraacetic Acid (EDTA), followed by flushing with 20 mL saline and then drying with paper points. Tooth no: 72 was extracted, and its pulp was extracted and subsequently implanted into the disinfected root canal along with induced apical bleeding. Calcium hydroxide iodoform paste was gently placed over the bleeding clot, and after forming a mineral trioxide aggregate (MTA) coronal barrier, the accessed cavities were restored using Z350 resin composite. The root developments were evaluated via radiographic imaging at 6 months, 1 year and 5 years after treatment. Imaging and clinical analysis showed closure of the apical foramen, thickening of the root canal wall, and satisfactory root length growth. Autologous transplantation might be useful to regenerate dental pulp in necrotic young permanent teeth., Competing Interests: The authors declare no conflict of interest., (©2024 The Author(s). Published by MRE Press.)

Background and Overview: Extraoral cutaneous sinus tracts (EOCST) are often misdiagnosed due to their unexpected appearance without history of odontogenic pain, discomfort, or cellulitis. Diagnosis can be further confounded in those with sensory processing difficulties since patients can have a hypersensitivity to sensory input, but simultaneously demonstrate hyposensitivity and indifference toward pain. EOCST misdiagnosis and resultant mismanagement can lead to multiple surgical excisions, biopsies, and elongated antibiotic regimens, with eventual lesion recurrence., Case Description: A 19-year-old white male with autism spectrum disorder in the period of transitional dental care presented with a history of a chronic EOCST. The patient required sedation for evaluation, biopsy, and was initially managed by infectious disease under the impression of an actinomycosis infection. The patient completed a twelve-month course of antibiotic therapy with subsequent lesion re-occurrence. Eventually, the diagnosis of an EOCST of dental origin was confirmed. It was determined that pulpal necrosis was due to localized dental trauma of the lower left central incisor, as a result of a self-injurious behavior. Root canal treatment eventually led to the resolution of the lesion. It took three years from initial clinical presentation for the resolution of the lesion., Conclusions and Practical Implications: Collaboration between the medical and dental healthcare team in diagnosis and treatment planning for a patient with special needs is essential to ensure prompt and appropriate care for this patient group., (© 2023 Special Care Dentistry Association and Wiley Periodicals LLC.)

Introduction: Modern tissue engineering strategies have elucidated the potential of regenerative endodontic treatment (RET) as an alternative for treating mature teeth., Methods: Here, we report two cases in which cell-based RET (CB-RET) using encapsulated allogeneic umbilical cord mesenchymal stem cells (UC-MSCs) in a platelet-poor plasma (PPP)-based scaffold was used in two mature teeth with pulp necrosis and apical periodontitis., Results: After 5 years of follow-up, the healing response was satisfactory in both cases, with evidence of pulp revitalization., Conclusions: This is the first study to report the success of an extended, 5-year follow-up for allogeneic CB-RET. This report presents an innovative and sustainable solution to challenging endodontic scenarios., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Dental pulp regeneration is challenging in endodontics. Cellular therapy is an alternative approach to induce dental pulp regeneration. Mesenchymal stromal cells (MSCs) have the capacity to induce dental pulp-like tissue formation. In this study, we evaluated the capacity of allogeneic bone marrow MSCs (BM-MSCs) to regenerate pulp following necrosis and apical periodontitis in children's permanent immature apex teeth., Methods: Patients aged 8 to 12 years with pulp necrosis and apical periodontitis were evaluated. The study included 15 teeth (13 incisors and 2 molars) from 14 patients (8 boys and 6 girls). Radiographic evaluation showed periapical radiolucency and immature apex teeth. There was no response to cold or electric pulp testing. The root canal of each tooth was cleaned, shaped, and Ca(OH) 2 used as an interappointment medication. Cryopreserved allogeneic BM-MSCs were thawed, expanded, incorporated into preclotted platelet-rich plasma, and implanted into the tooth's pulp cavity. They were sealed with bioceramic cement and composite. Sensibility, apical foramen, calcium deposits within the root canal, and resolution of periapical lesions were evaluated in each tooth over the following 12 months., Results: Based on 9 variables established for dental pulp-like tissue regeneration, all MSC-treated teeth showed evidence of successful regeneration. Clinical and radiographic evaluation of the treated teeth showed periapical lesion healing, sensitivity to cold and electricity, decreased width of the apical foramen, and mineralization within the canal space., Conclusions: Transplantation of allogeneic MSCs induces the formation of dental pulp-like tissue in permanent immature apex teeth with pulp necrosis and apical periodontitis. Implant of MSCs constitutes a potential therapy in regenerative endodontics in pediatric dentistry. Future studies incorporating a larger sample size may confirm these results., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Background: With increasing studies being published on regenerative endodontic procedures (REPs) as a treatment modality for mature necrotic teeth, the assessment of outcomes following regenerative endodontic procedures has become more challenging and the demand for a better understanding of the regenerated tissues following this treatment is rising. The study aimed to correlate cold, electric pulp testing (EPT), and magnetic resonance imaging (MRI) signal intensity (SI) in mature necrotic teeth treated with regenerative endodontic procedures., Methodology: This retrospective cohort study included eighteen adult patients who experienced tooth necrosis in mature maxillary anterior teeth recruited from the outpatient clinic, Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt from July 2017 until December 2018 with 12 months of follow-up. regenerative endodontic procedures via blood clot were performed. The canals were instrumented by ProTaper Next (PTN) files until final sizes X3 or X5. Biodentine was used as cervical plug material. Pre and post-operative clinical follow-up was done where the patients' responses to cold and electric pulp testing were given a scoring system and were compared to the normal contralateral tooth. Pre and post-operative magnetic resonance imaging signal intensity of both the involved tooth and its contralateral at the middle and the apical thirds of the root canals were assessed after 3, 6, and 12 months. Data was analyzed using the ANOVA, Friedman and Bonferroni tests. Significance was set at a p-value < 0.05., Results: All 18 teeth scored a baseline score of "2" for cold and electric pulp testing. There was a significant difference between scores of the cold test at baseline and 12-month follow-up (p < 0.001). There was a significant difference between scores of the electric pulp testing of baseline and 12-month follow-up (p < 0.001). There was a moderately significant indirect (inverse) correlation between magnetic resonance imaging signal intensity and cold test in both the middle and apical thirds at 12 months. No significant correlations were detected between magnetic resonance imaging signal intensity and electric pulp testingat any of the time intervals (p > 0.05)., Conclusion: Magnetic resonance imaging is a successful non-invasive method to assess outcomes of regenerative endodontic procedures and correlating it with another reliable method of assessing pulpal responses, cold test, could validate these outcomes., Clinical Trial Registration: The study was registered with ClinicalTrials.gov (ID: NCT03804450)., (© 2024. The Author(s).)

Background: In the regenerative endodontic procedures, scaffolds could influence the prognosis of affected teeth. Currently, there is controversy regarding the postoperative evaluation of various scaffolds for pulp regeneration. The objective of this study was to access whether other scaffolds, used alone or in combination with blood clot (BC), are more effective than BC in regenerative endodontic procedures., Methods: We systematically search the PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and Google Scholar databases. Randomized controlled trials examining the use of BC and other scaffold materials in the regenerative endodontic procedures were included. A random effects model was used for the meta-analysis. The GRADE method was used to determine the quality of the evidence., Results: We screened 168 RCTs related to young permanent tooth pulp necrosis through electronic and manual retrieval. A total of 28 RCTs were related to regenerative endodontic procedures. Ultimately, 12 articles met the inclusion criteria and were included in the relevant meta-analysis. Only 2 studies were assessed to have a low risk of bias. High quality evidence indicated that there was no statistically significant difference in the success rate between the two groups (RR=0.99, 95% CI=0.96 to 1.03; 434 participants, 12 studies); low-quality evidence indicated that there was no statistically significant difference in the increase in root length or root canal wall thickness between the two groups. Medium quality evidence indicated that there was no statistically significant difference in pulp vitality testing between the two groups., Conclusions: For clinical regenerative endodontic procedures, the most commonly used scaffolds include BC, PRP, and PRF. All the different scaffolds had fairly high clinical success rates, and the difference was not significant. For regenerative endodontic procedures involving young permanent teeth with pulp necrosis, clinical practitioners could choose a reasonable scaffold considering the conditions of the equipment and patients., (© 2024. The Author(s).)

Aim: The present retrospective cohort study aimed to evaluate luxated permanent teeth for pulp prognosis and risk factors., Methodology: Case records and radiographs of 224 patients, involving 427 luxated permanent teeth, referred for treatment at the Dental Trauma Center-School of Dentistry, Universidade Federal de Minas Gerais, (DTC-SD-UFMG) from 2014 to 2022, were assessed for pulp prognosis classified as vitality, necrosis and pulp canal obliteration (PCO). A competing risk survival analysis estimated the hazards of the three outcomes, and the effect of demographic, clinical and treatment variables was tested using a cause specific Cox regression model., Results: Pulp vitality was found in163 teeth (38.2%), pulp necrosis in 120 teeth (28.1%) and 55 teeth (12.9%) developed PCO. Pulp vitality decreased in the presence of concomitant crown fractures (HR 0.38 95% CI [0.2-0.8] p = 0.006). The risk of pulp necrosis (HR 0.62 95% CI [0.4-0.96] p = 0.03) was lower in cases with open apices but increased with concomitant crown fractures (HR 4.0 95% CI [2.6-6.1] p = 0.001) and intrusions (HR 2.3 95% CI [1.2-4.1] p = 0.007). Lateral or extrusive luxations (HR 3.0 95% CI [1.3-6.9] p = 0.001) and open apices (HR 2.4 95% CI [1.2-4.7] p = 0.01) showed higher rates of PCO., Conclusion: Type of luxation, the diameter of the apical foramen, and the presence of concomitant crown fractures were main determinants of pulp prognosis after luxation injuries in permanent teeth., Clinical Relevance: Pulp prognosis after tooth luxation is dependent on the presence and direction of tooth displacement together with infection control., Clinical Trial Registration: Not applicable., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: This study aims to investigate the ability of umbilical cord mesenchymal stem cells (UC-MSC) to enhance the regeneration of pulp-dentin complex in immature permanent teeth with irreversible pulpitis., Methods: A total of 32 mandibular premolar teeth with immature apices in 5 dogs were used in this in-vivo randomized controlled trial (RCT). Eight healthy teeth without pre-existing pathosis served as the positive control samples and received no treatment, while in another 8 teeth, the pulp was completely extirpated (negative control). Class V cavities were prepared to induce inflammation in the remaining 16 teeth (groups 3 and 4) and the pulp was extirpated 2-4 mm short of the radiographic apex. Of the 16, the 8 teeth in group 4 received 1 mL of cord blood stem cells with a hydrogel scaffold. Blood clots were covered with mineral trioxide aggregates at the cementoenamel junction in the experimental groups, and teeth were filled with RMGI and composite. Three months later, block sections were removed for histologic evaluations for the evaluation of postoperative apical closure, degree of inflammation, and presence of normal pulp tissue. The data were statistically analyzed with the chi-square test (P < .05)., Results: All teeth with complete pulp extirpation demonstrated pulpal necrosis with no postoperative closure of their apices, while apical closure was seen in all the teeth in the remaining groups. There was a statistically significant (P < .001) difference in the presence of inflammation and normal pulp tissue between the experimental groups. The teeth in group 3 showed normal pulp tissue extending to the level of MTA, but there was inflammation within the canal space. In contrast, the teeth in the UC-MSC group demonstrated organized, normal pulp tissue with no inflammation., Conclusion: Based on these results, the regeneration of the pulp-dentin complex is possible with no inflammation when UC-MSCs are used and 2-4 mm of the apical pulp remains intact in immature teeth with irreversible pulpitis., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Aim: The aim of this study was to assess which treatment modality regarding scaffold selection for immature permanent teeth with pulpal necrosis will be the most successful for regenerative endodontic treatment (RET)., Methodology: PubMed, Cochrane, Web of Science and Embase, and additional records until August 2022 were searched providing a total of 3021 articles, and nine of these articles were included for quantitative synthesis. The reviewers selected eligible randomized controlled trials and extracted pertinent data. Network meta-analysis was conducted to estimate treatment effects for primary outcomes (clinical and radiographic healing) and secondary outcomes (apical closure, root length and root wall thickness increase) following RET [mean difference (MD); 95% credible interval (CrI) and surface under the cumulative ranking curve (SUCRA)]. The quality of the included studies was appraised by the revised Cochrane risk of bias tool, and the quality of evidence was assessed using the GRADE approach., Results: Six interventions from nine included studies were identified: blood clot scaffold (BC), blood clot scaffold with basic fibroblast growth factor, blood clot scaffold with collagen, platelet pellet, platelet-rich plasma (PRP) and platelet-rich fibrin (PRF). The PRP scaffold showed the greatest increase in root lengthening at 6-12 months (MD = 4.2; 95% CrI, 1.2 to 6.8; SUCRA = 89.0%, very low confidence). PRP or PRF achieved the highest level of success for primary and secondary outcomes at 1-6 and 6-12 months. Blood clot scaffold (with collagen or combined with basic fibroblast growth factor (bFGF)) achieved the highest level of success for secondary outcomes beyond 12 months follow-up. A very low to low quality of evidence suggests that both PRP and PRF exhibit the greatest success evaluating primary and secondary outcomes within 12 months postoperatively compared to the traditional blood clot scaffold protocol., Conclusion: Limited evidence suggests both PRP and PRF exhibit success in the short-term, not long-term. The value of this information stems in its recommendation for future randomized trials prioritizing both of these materials in their protocol., (© 2023 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Background/aim: This study aimed at comparing the regenerative potential of injectable platelet-rich fibrin (i-PRF) (Group 1) and platelet-rich plasma (Group 2) scaffolds., Materials and Methods: Twenty-three patients, aged from 9 to 24 years, having 24 immature traumatized necrotic maxillary anterior teeth, were enrolled. Teeth trauma was confirmed by patients' history. Preoperative three-dimensional scans were done. In the first visit, canals were irrigated with 1.5% sodium hypochlorite then medicated with calcium hydroxide. After 2 weeks, patients were randomly assigned into one of the treatment groups (n = 12). The platelet concentrate was applied after centrifuging 10 mL of autologous venous blood with respect to the centrifugation protocol for each platelet concentrate. Patients were recalled at 6 and 12 months posttreatment, during which clinical and radiographic examinations and assessment of pulp sensitivity were done. Three-dimensional scanning was done after 12 months. The increase in root length and decrease in root canal diameters were calculated at three canal levels. Statistical analysis was done using the paired t-test and the independent t-test. The significance level was set at p < .05., Results: There was no statistically significant difference between both groups regarding the increase in root length, decrease in coronal and middle canal diameters and the response to the electric pulp tester. Group (1) showed significantly greater decrease in apical canal diameter than Group (2) (p = .008)., Conclusion: I-PRF can be considered as a valid regenerative scaffold for clinical use and with regards to the easier preparation technique, it is more recommended than platelet-rich plasma., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The utility and feasibility of pulp regenerative therapy with autologous dental pulp stem cells (DPSCs) in mature teeth with irreversible pulpitis were clinically demonstrated. On the other hand, there is no evidence of the utility of DPSCs in mature teeth with apical periodontitis. The aim of this case report was to describe the potential utility of regenerative cell therapy in mature teeth with apical periodontitis. A 44-year-old man was referred for pulp regeneration due to a periapical lesion in his maxillary first premolar. Root canal disinfection was performed by irrigation and intracanal medication by nanobubbles with levofloxacin and amphotericin B in addition to conventional irrigation. Autologous DPSCs isolated from an extracted third molar were transplanted into the root canal after residual bacteria and fungi were below the detection level by polymerase chain reaction assay using universal genes to amplify specific regions within bacterial 16S ribosomal DNA and fungal ribosomal DNA (ITS1), respectively. There were no adverse events or systemic toxicity assessed for clinical evaluations during the 79-week-follow-up period and laboratory evaluations after 4 weeks. The affected tooth was responsive to the electric pulp test. Cone-beam computed tomographic imaging revealed a reduced lesion size, remission of the periapical tissue, and mineralized tissue formation in the apical part of the canal after 79 weeks. The signal intensity on magnetic resonance imaging of the regenerated tissue in the affected tooth was comparable to that of the normal pulp in the adjacent teeth after 24 weeks. This case report demonstrated the potential use of DPSCs for pulp regenerative therapy in mature teeth with apical periodontitis., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

The Aim: Jf the study was to assess the efficacy of mineral trioxide aggregate for treatment of children with complicated permanent teeth trauma., Material and Methods: The study comprised 29 children aged 6-13 years (mean age 8.6±1.7 years) with 36 injured constant teeth, from which 30 had immature roots, 27 (75%) teeth had necrotic pulp at baseline examination, 12 (33.3%) teeth showed radiological signs of external imflammatory root resorbtion, 2 teeth were diagnosed with of the root fracture (5.6%). MTA was used for pulp regeneration procedure in 25 (69.5%) teeth, external closure of resorbtion site in 3 (8.3%) teeth, root canal filling in 4 (11.1%) teeth, apical plug creation in 4 teeth (11.1%). The patients were folowed up for 1 to 9 years., Results: From 36 teeth only one was extracted 9 years after regenerative endodontic procedure because of cervical root fracture. In 2 teeth with external imflammatory resorbtion progession of replacement resorption took place, in 1 tooth necrosis of regenerated pulp tissue occurred 2 years after the procedure because of restoration marginal seal failure. In 25 teeth favorable outcome was registered with stabilisation of external root resorbtion, continous root growth in 24 teeth and radioluscent lesions healing in 6 teeht showing them at baseline examination. Change of external imflammator root resorbtion to replacement resorption was detected in 1 teeth from 3 with external closure of resorbtion site. Root calan filling with MTA was performed in 3 avulsed teeth with replantation delayed for more than 1 day and in 1 tooth with root fracture. All teeth were clinically asymptomatic during more than 5 years follow-up. Favorable outcome was received in all cases of apicl plug formation., Conclusion: MTA is highly effective for preservation of constant teeth in children with clinically complicated situations. In many cases with hopeless long-term prognosis for a teeth MTA allows stabilization of dental tissue level with the teeth being an object for guided tissue regeneration.

Aim: This report addresses the management of a large persistent discharging lesion in an 11-year-old boy. The report describes the use of aspiration-irrigation technique for the management of immature necrotic tooth with persistent discharge after a failed regenerative procedure., Background: Regenerative endodontics aim to provide an increase in root canal width, length, and in apical closure. Alternative procedures, such as apexification, should be attempted when regeneration fails. If the canal cannot be dried to persistent discharge, the aspiration-irrigation technique can be used. The technique relies on using aspiration along with irrigation to remove pus from the periapical area., Case Description: This is a case for an 11-year-old patient who had trauma to tooth #11, which resulted in the complicated crown fracture. He had an emergency management that included pulpectomy and intracanal medication at another clinic. Two years later, the patient was presented to our clinic. Upon examination, the diagnosis was previously initiated therapy with asymptomatic apical periodontitis in immature tooth #11. Regeneration was attempted first but failed. The mineral trioxide aggregate (MTA) plug was removed, and the canal had persistent pus discharge. The canal was filled with intracanal medication, and then 2 weeks later, the canal was filled with triple antibiotic paste (TAP). Next visit, and due to continuous discharge, tooth #11 was treated conservatively with an intracanal aspiration-irrigation technique. An IrriFlex needle attached to a high-volume suction was used to aspirate the cystic fluid. Mineral trioxide aggregate plug apexification was performed in a later visit and the tooth was restored., Conclusion: During the 3-month and 16-month follow-up, there was resolution of the symptoms, a decrease in the periapical lesion size, and soft tissues appeared within normal limits., Clinical Significance: Regenerative procedures are a good option for immature necrotic teeth. These procedures may fail due to persistent pus discharge from the root canals. The aspiration-irrigation technique is a good treatment option in cases of consciously discharging canals. How to cite this article: Alsofi L, Almarzouki S. Failed Regenerative Endodontic Case Treated by Modified Aspiration-irrigation Technique and Apexification. J Contemp Dent Pract 2024;25(1):92-97.

Objectives: This retrospective study was undertaken to clinically and radiographically evaluate the long-term outcomes of regenerative endodontic procedures (REPs) for nonvital mature permanent teeth, to analyze predictors influencing treatment outcomes., Methods: Nonvital mature permanent teeth treated by REPs with a minimum follow-up period of 6 months were included from 2015 to 2017. Treatment outcomes were categorized as success and failure. The periapical status and lesion healing were assessed in terms of the periapical index (PAI) and the percentage changes in periapical radiolucency (PARL) area. The clinical and radiographic outcomes of REPs were assessed by Mann-Whitney test at different follow-up period. Kaplan-Meier curves and Univariate Cox regression analysis were conducted to assess the success and identify potential predictors affecting outcomes, respectively., Results: A total of 37 mature teeth with an average follow-up of 4.3 years satisfied the criteria, and 89.2% of the teeth had a successful outcome. Significant differences in PAI scores were found between each period with respect to the baseline (p < .05). Among different periods, there was a significant difference between intervals of 3-6 months and 7-12 months (p = .039) and no significant difference between each interval of more than 12 months (p > .05). Eighty-seven percent of teeth with preoperative PARL presented completely healed. REPs significantly decreased the PARL area at the interval of 7-12 months compared to 3-6 months (p = .025), with no significant difference between each interval of more than 12 months (p > .05). No significant predictor was found for the success of outcome (p > .05). Thirteen teeth (35.1%) regained pulp sensibility, and 40.5% of the teeth exhibited intracanal calcification., Conclusions: Within the limitations of this study, REPs provided a high long-term success rate and promoted the resolution of PARL as a biologically-based alternative treatment option for nonvital mature teeth., Clinical Relevance: REPs provide a high long-term success rate and promoted healing of apical periodontitis comparable with reported outcomes for root canal therapy of mature teeth., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: What if we changed our point of view? What if we approached endodontics from a biological perspective rather than a mechanistic one? What if, in the case of pulpal tissue necrosis, we were to consider an alternative to apexification therapies? Is pulp tissue regeneration now possible?, Objective: Regenerative endodontic therapy (RET) aims to regenerate the pulp-dentin complex damaged by infection, trauma, or developmental anomaly of immature permanent teeth with necrotic pulp. The new intracanal tissue formation is expected to display pulp-like architecture and functions. There are two different based to tissue engineering approaches described to perform RET: cell-free CF-RET that attempt to induce host endogenous cells or stem cells to migrate into the root canal for regeneration or cell-based CB-RET which introduce exogenously prepared cells or stem cells into the canal for regeneration., Material and Method: CB-RET is the basis of current protocols recommended by the American Association of Endodontists (AAE) and the European Society of Endodontology (ESE) for the treatment of necrotic immature permanent teeth, with or without LIPOE. In this article, after defining the above-mentioned concepts, we will describe the ESE protocol and discuss the key steps for "getting started with endodontic regeneration"., Conclusion: Each stage of the protocol must be carried out rigorously so as not to compromise the stages of the various biological processes involved. The practitioner has to stay informed of advances in knowledge resulting from research and new protocols to be published.

Objectives: This review aims to discuss the implications of anatomy of the root, pulp chamber, and canals on pulpotomy and revitalization procedures (RPs) as treatment alternatives to root canal treatment procedures., Methods: This narrative review was undertaken to address two main questions - why remove vital pulp tissue in teeth with complex canal anatomy when it can be preserved? And why replace the necrotic pulp in teeth with mature roots with a synthetic material when we can revitalize? This review also aims to discuss anatomical challenges with pulpotomy and revitalization procedures., Results: Maintaining the vitality of the pulp via partial or full pulpotomy procedures avoids the multiple potential challenges faced by clinicians during root canal treatment. However, carrying out pulpotomy procedures requires a meticulous understanding of the pulp chamber anatomy, which varies from tooth to tooth. Literature shows an increased interest in the application of RPs in teeth with mature roots; however, to date, the relation between the complexity of the root canal system and outcomes of RPs in necrotic multi-rooted teeth with mature roots is unclear and requires further robust comparative research and long-term follow-up., Conclusions: Whenever indicated, pulpotomy procedures are viable treatment options for vital teeth with mature roots; however, comparative, adequately powered studies with long-term follow-up are needed as a priority in this area. RPs show promising outcomes for necrotic teeth with mature roots that warrant more evidence in different tooth types with long-term follow-ups.  CLINICAL RELEVANCE: Clinicians should be aware of the pulp chamber anatomy, which is subject to morphological changes by age or as a defensive mechanism against microbial irritation, before practicing partial and full pulpotomy procedures. RP is a promising treatment option for teeth with immature roots, but more evidence is needed for its applications in teeth with mature roots. A universal consensus and considerably more robust evidence are needed for the standardization of RPs in teeth with mature roots., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Few studies have compared the outcomes of regenerative endodontic procedures (REPs) and calcium hydroxide apexification focusing on necrotic teeth with dens evaginatus., Aim: To qualitatively and quantitatively compare the treatment outcomes of REPs and calcium hydroxide apexification in teeth with dens evaginatus., Design: Immature permanent necrotic evaginated teeth treated with REPs or calcium hydroxide apexification for a follow-up period of at least 12 months were included. Tooth success and survival rates were analyzed. Changes in radiographic root length, apical diameter, and radiographic root area (RRA) were quantified. Prognostic factors that might influence RRA were identified via multivariate linear regression analysis., Results: A total of 112 teeth (50 REP cases and 62 apexification cases) with a median follow-up period of 26.5 months were included. Regenerative endodontic procedures and calcium hydroxide apexification exhibited similar satisfactory success and survival rates (p > .05). Additionally, 88 teeth were quantitatively analyzed. The REP group presented a significantly greater percentage increase in RRA and less decrease in apical diameter than the calcium hydroxide apexification group (p < .05). Teeth treated with REPs and with Stages 7 and 8 of root development showed a better gain in RRA (p < .05)., Conclusion: While REP and calcium hydroxide apexification had similar success and survival rates, teeth with REPs showed an increase in RRA, indicating that REP is the preferred choice., (© 2023 BSPD, IAPD and John Wiley & Sons Ltd.)

Background: Revitalization procedures primarily aim to eliminate clinical symptoms and heal periapical lesions., Objectives: The objective of the study was to elucidate the effectiveness of revitalization in treating apical periodontitis in necrotic mature and immature permanent teeth based on the following PICO question: In patients with permanent immature or mature teeth and pulp necrosis with or without signs of apical periodontitis (P) what is the effectiveness of revitalization (I) in comparison with calcium hydroxide apexification, apical plug and root canal treatment (C) in terms of tooth survival, pain, tenderness, swelling, need for medication (analgesics and antibiotics), radiographic evidence of reduction of apical lesion size, radiographic evidence of normal periodontal ligament space, radiographic evidence of increased root thickness and length (not for mature teeth), tooth function (fracture and restoration longevity), need for further intervention, adverse effects (including exacerbation, restoration integrity, allergy and discolouration), oral health-related quality of life (OHRQoL), presence of sinus tract and response to sensibility testing (O). (T) = Defined as a minimum of 1 year and maximum of as long as possible for all outcome measures, except 'pain, tenderness, swelling, need for medication (analgesics)', which is a minimum of 7 days and maximum of 3 months and OHRQoL which is minimum of 6 months and a maximum of as long as possible., Methods: Three databases (PubMed, Embase and Cochrane Library) were searched for human, experimental and observational studies in English, complemented with hand search, until 31/10/2021. Studies recruiting teeth with pulp necrosis (with/without apical periodontitis), with minimum 10 teeth/arm at the end of the study and with a follow-up of at least 1 year, were included. Records without an abstract and a full text were excluded. The qualitative analysis of the included (non-) randomized controlled clinical trials was performed with the Revised Cochrane risk-of-bias tools (RoB 2 and ROBINS-I). Meta-analysis for survival and success (including a subgroup analysis for mature/immature permanent teeth) was performed using the Mantel-Haenszel method. The certainty of evidence was assessed using GRADE (Grades of Recommendation, Assessment, Development and Evaluation)., Results: From the 365 identified records, five met the inclusion criteria. The 12 months survival rate was 100% for all (im)mature permanent teeth in all groups (3 studies). The success rate at 12 months was 100% for immature permanent teeth for I and C (1 study), however, reduced to 92% and 80% for mature teeth in I and C respectively (1 study, p > .05). The risk of bias for the most critical outcome (survival) was high for two studies and low for one. For the critical outcome success, all assessed studies were highly biased. Meta-analyses provided pooled relative risk with no statistically significant difference between I and C for both survival (RR = 1.00, 95%CI = 0.96-1.04, p = 1.00) and success (RR = 1.06; 95%CI = 0.83-1.35, p = .66). The evidence level for survival was kept 'low' and for success was downgraded to 'very low' due to inconsistency and imprecision., Discussion: The survival and success rates were favourable in all included studies and for all groups; however, these outcomes are not reliable due to the low certainty level. Clinically, the most reported adverse event was tooth discolouration, hence the application of bismuth oxide containing calcium silicate cements should be avoided in revitalization. Radiographically, caution is needed when assessing periapical bone healing and further root development with periapical radiographs, due to multifactorial inaccuracies of this imaging technique. Methodological and assessment concerns need to be addressed in future clinical trials. Long-term results are necessary for studies reporting revitalization of mature permanent teeth, as they seem to be experimental so far., Conclusions: No robust evidence was discovered to support that revitalization is effective to treat apical periodontitis in (im)mature permanent teeth. The success and survival rates of revitalized and fully pulpectomized (im)mature permanent teeth did not differ significantly., Registration: Prospero: CRD42021262466., (© 2022 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Introduction: Dens evaginatus (DE) is a dental anomaly with a supernumerary tubercle projection that typically contains dentin and pulp tissue. However, the tubercle projection can fracture, exposing the dentin and potentially the dental pulp, which induces pulpal diseases. Managing DE should be primarily based on the clinical diagnosis of the pulp., Methods: The literature search in prevalence, prophylaxis, and management of dens evaginatus was performed in PubMed database as well as by manual search, in which the related contents were collected and descriptively analyzed., Results: Of the 264 searched literatures, 62 articles were included for this scoping review. The prophylactic management of the tubercle of DE teeth with a normal pulp should be performed as early as possible by the prep-and-fill technique or the reinforcement technique to preserve tooth vitality and continued root development, with the former reported to be superior compared with the latter. Furthermore, DE teeth with reversible pulpitis should be managed with the prep-and-fill technique. For DE teeth with irreversible pulpitis, vital pulp therapy, ie, partial or full/coronal pulpotomy, should be considered when the pulpal inflammation is limited to the coronal pulp to preserve the vitality of the radicular pulp that induces apexogenesis. A pulpectomy should be performed if the pulpal inflammation has progressed into the radicular pulp. For DE teeth with pulpal necrosis (or after pulpectomy) and immature roots, mineral trioxide aggregate apexification or regenerative endodontic procedures are the treatment options. For DE teeth with pulpal necrosis and complete root formation, nonsurgical root canal treatment is the treatment of choice. A flow chart of the decision-making for managing DE teeth based on pulpal diagnosis is proposed., Conclusion: DE teeth should be properly managed, by prophylaxis or treatment, depending on pulpal diagnosis and related factors., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Tumor necrosis factor (TNF)-α is a pro-inflammatory cytokine that promotes biomineralization in vitro in dental pulp cells. However, the role of TNF-α-TNF receptor 1 (TNFR1) signaling in reparative dentin formation and related inflammatory pathways is not known. Therefore, the aim of this study was to evaluate the role of the TNF-α-TNFR1 axis in dental pulp repair following pulp capping in vivo., Methods: Dental pulp repair response of genetically deficient TNF-α receptor-1 mice (TNFR1 -/- ; n = 20) was compared with that of C57Bl6 mice (wild type [WT]; n = 20). Pulp capping was performed with mineral trioxide aggregate on the mandibular first molars of mice. After 7 and 70 days, tissues were collected and stained with hematoxylin and eosin for histopathological and histometric evaluation, and assessed by the Brown and Brenn methods for histomicrobiological analysis and by immunohistochemistry to localize TNF-α, Runt-related transcription factor 2, Dentin Sialoprotein (DSP) and Osteopontin (OPN) expression., Results: Compared with WT mice, TNFR1 -/- mice showed significantly decreased reparative dentin formation with a lower mineralized tissue area (P < .0001). Unlike WT mice, TNFR1 -/- mice also exhibited significant dental pulp necrosis, neutrophil recruitment, and apical periodontitis formation (P < .0001) without bacterial tissue invasion. TNFR1 -/- animals further exhibited decreased TNF-α, DSP, and OPN expression (P < .0001), whereas Runt-related transcription factor 2 expression was unchanged (P > .05)., Conclusion: The TNF-α-TNFR1 axis is involved in reparative dentin formation following dental pulp capping in vivo. Genetic ablation of TNFR1 modified the inflammatory process and inhibited the expression of the DSP and OPN mineralization proteins, which culminated in dental pulp necrosis and development of apical periodontitis., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: In a growing child, preservation of traumatized immature permanent upper incisors is challenging. This study aimed to evaluate the long-term outcome of endodontically treated traumatized immature upper incisors and associated variables., Methods: A total of 183 traumatized immature upper incisors treated with pulpotomy, apexification, or regenerative endodontic procedure (REP), with follow-up between 4 and 15 years, were assessed for presence of pulpal responses or periodontal/bone responses using standardized clinical and radiologic criteria. Logistic regression, including stage of root development, type and complexity of traumatic event, type of endodontic intervention, and history of orthodontic management, were used to estimate impact on tooth survival and occurrence of tissue responses. Study approved by Ethics Committee Research UZ/KU Leuven (S60597)., Results: After a median follow-up of 7.3 years (interquartile range, 6.1-9.2), 159 teeth (86.9%) were still functional. From these teeth, 58 (36.5%) developed tissue responses. This was significantly associated with stage of root development at moment of trauma (root length <¾) and type of endodontic intervention (REP presenting worst outcome). Tooth loss (24 teeth, 13.1%) occurred after a mean time span of 3.2 years (±1.5) and was significantly associated with type and complexity of the traumatic event and type of endodontic intervention, with apexification showing better results than REP (odds ratio, 0.30; 95% confidence interval, 0.11-0.79)., Conclusions: A large number of endodontically treated traumatized immature teeth could be kept functional. Very immature teeth, teeth with periodontal tissue damage, and teeth treated with REP were at highest risk for an unfavorable outcome., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Data Sources: Five scientific databases were electronically searched: PubMed, EMBASE, OpenGrey, Web of Science and Cochrane Library.  The search was conducted until 17 February 2022 without any restriction on date of publication but was restricted to English language. Relevant studies were also screened for related publications. The aim of this systematic review and meta-analysis was to evaluate the effectiveness of regenerative endodontic procedures (REPs) in mature and immature permanent teeth with necrotic pulp and to evaluate if the success rate was affected by the stage of root development., Study Selection: Types of studies: all of the included studies were randomised controlled trials (RCTs)., Types of Participants: people with necrotic permanent teeth (immature or mature) treated with regenerative endodontic procedures. Types of interventions: regenerative endodontic procedures. Language: RCTs published in English., Exclusion Criteria: Types of studies: (1) case reports, (2) retrospective cohort trials, (3) prospective cohort trials, (4) animal trials, (5) in-vitro trials, (6) non-randomised trials., Population: primary teeth. Types of interventions: no details about the clinical procedures. Follow-up period: <6 months., Data Extraction and Synthesis: The titles and abstracts of the RCTs identified by the search strategies were independently screened by two reviewers. After the initial screening, the full text of the relevant trials were reassessed against the inclusion and exclusion criteria. Discrepancies and disagreements were resolved by consensus after including a third reviewer., Results: Following the initial electronic and manual searches, a total of 3766 articles were initially identified. This was reduced to 2739 articles after duplicates were removed. However, after the initial screening phase, 35 articles were considered potentially relevant and qualified for full-text scrutiny. Out of the 35 articles, only 27 were considered eligible for inclusion. The differences in the success rate and the asymptomatic rate between the mature and immature permanent teeth with necrotic pulp were not statistically significant. However, the differences between the two groups were statistically significant in the rate of positive response to electrical pulp testing., Conclusions: Based on the results of this systematic review and meta-analysis, the authors concluded that REPs are an effective therapy and can achieve high success rates for both mature and immature necrotic permanent teeth. It was also concluded that the REPs were more successful in regaining vitality responses for mature compared with immature permanent teeth with necrotic pulps., (© 2023. The Author(s), under exclusive licence to British Dental Association.)

Previous studies have reported successful clinical outcomes after regenerative endodontic procedures (REPs) for immature permanent teeth with pulpal infection. However, it remains unclear whether the procedures promote true regeneration or repair. This case report describes the histologic and electron microscopic characteristics of a human immature permanent premolar with a chronic apical abscess that was treated with an REP. Tooth #20 of a 9-year-old girl underwent an REP. At the 6-year follow-up, the patient was asymptomatic, and closure of the apex and thickening of the dentinal walls were observed. However, 16 years after the procedure, apical periodontitis recurred, necessitating apical surgery. The resected root fragments were obtained during the surgery and analyzed using micro-computed tomography, light microscopy, and scanning electron microscopy. Distinct dentinal tubules and interglobular dentin were observed in the regenerated hard tissue. Cementum-like tissue and a root canal were also observed in the apical fragment. The regenerated root tissue in this case exhibited a structure similar to the native root structure. Therefore, we believe that cell-free REPs possess regenerative potential for teeth diagnosed with pulp necrosis and chronic apical abscess., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: This study aimed to evaluate treatment outcomes of regenerative endodontic treatment (RET) in nonvital immature permanent teeth due to developmental malformation and trauma, and to analyze the influence of etiology on the prognosis., Methods: Fifty-five cases were included and divided into a malformation group (n = 33) and a trauma group (n = 22). Treatment outcomes were classified as healed, healing, and failure. Root development was evaluated in terms of root morphology and the percentage changes in root length, root width, and apical diameter during a follow-up period of 12-85 months (mean 30.8 months)., Results: The mean age and the mean degree of root development in the trauma group were significantly younger than that in the malformation group. The success rate of RET was 93.9% (81.8% healed, 12.1% healing) in the malformation group and 90.9% (68.2% healed, 22.7% healing) in the trauma group, showing no statistically significant difference. The proportion of type I-III root morphology in the malformation group (97%, 32/33) was significantly higher than that in the trauma group (77.3%, 17/22) (P < .05), whereas there was no significant difference in the percentage changes of root length, root width, and apical diameter between the 2 groups. Six cases (6/55, 10.9%) showed no significant root development (type IV-V) (1 in the malformation group and 5 in the trauma group). Six cases (6/55, 10.9%) revealed intracanal calcification., Conclusions: RET achieved reliable outcomes regarding the healing of apical periodontitis and continued root development. The etiology seems to influence the outcome of RET. Malformation cases presented with a better prognosis than trauma cases after RET., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Understanding the healing process of dental pulp after tooth autotransplantation (TAT) and regenerative endodontic treatment (RET) of immature teeth is important both clinically and scientifically. This study aimed to characterize the pattern of dental pulp healing in human teeth that underwent TAT and RET using state-of-the-art imaging techniques., Materials and Methods: This study examined 4 human teeth, 2 premolars that underwent TAT, and 2 central incisors that received RET. The premolars were extracted after 1 year (case 1) and 2 years (case 2) due to ankylosis, while the central incisors were extracted after 3 years (cases 3 and 4) for orthodontic reasons. Nanofocus x-ray computed tomography was used to image the samples before being processed for histological and immunohistochemical analysis. Laser scanning confocal second harmonic generation imaging (SHG) was used to examine the patterns of collagen deposition. A maturity-matched premolar was included as a negative control for the histological and SHG analysis., Results: Analysis of the 4 cases revealed different patterns of dental pulp healing. Similarities were observed in the progressive obliteration of the root canal space. However, a striking loss of typical pulpal architecture was observed in the TAT cases, while a pulp-like tissue was observed in one of the RET cases. Odontoblast-like cells were observed in cases 1 and 3., Conclusions: This study provided insights into the patterns of dental pulp healing after TAT and RET. The SHG imaging sheds light on the patterns of collagen deposition during reparative dentin formation., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)