Radiographic and clinical outcomes of the treatment of immature permanent teeth by revascularization or apexification: a pilot retrospective cohort study

Machine learning models for prognosis prediction in regenerative endodontic procedures

BACKGROUND

This study aimed to establish and validate machine learning (ML) models to predict the prognosis of regenerative endodontic procedures (REPs) clinically, assisting clinicians in decision-making and avoiding treatment failure.

METHODS

A total of 198 patients with 268 teeth were included for radiographic examination and measurement. Five Machine Learning (ML) models, including Random forest (RF), gradient boosting machine (GBM), extreme gradient boosting (XGB), Logistic regression (logR) and support vector machine (SVM) are implemented for the prediction on two datasets of follow-up periods of 1-year and 2-year, respectively. Using a stratified five folds of cross-validation method, each dataset is randomly divided into a training set and test set in a ratio of 8 : 2. Correlation analysis and importance ranking were performed for feature extraction. Seven performance metrics including area under curve (AUC), accuracy, F1-score, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated to compare the predictive performance.

RESULTS

The RF (Accuracy = 0.91, AUC = 0.94; Accuracy = 0.84, AUC = 0.86) and GBM (Accuracy = 0.91, AUC = 0.93; Accuracy = 0.84, AUC = 0.85) had the best and similar performance simultaneously in the prediction of 1-year follow-up period and 2-year follow-up period, respectively. The variables applied to predict the primary outcome in REPs were ranked accordingly to their values of feature importance, including age, sex, etiology, the number of root canals, trauma type, swelling or sinus tract, periapical lesion size, root development stage, pre-operative root resorption, medicaments, scaffold, second REPs, previous root canal filling.

CONCLUSIONS

RF and GBM models outperformed XGB, logR, SVM models on the overall performance on our datasets, exhibiting the potential capability to predict the prognosis of REPs. The ranking of feature importance contributes to establishing the scoring system for prognosis prediction in REPs, assisting clinicians in decision-making.

Time-Dependent Morphological Changes in Traumatic Immature Teeth With Necrotic Pulps Following Regenerative Endodontic Treatment: A Retrospective Study

BACKGROUND/AIM

Regenerative endodontic treatment is a promising approach for healing periapical lesions and continuous root maturation. Although previous studies have reported its outcomes, the dynamics of morphological changes over time remain unclear. Therefore, this study aimed to evaluate changes in the periapical status and root dimensions over a 60-month follow-up period.

MATERIALS AND METHODS

The follow-up duration, periapical status changes, calcific barrier formation, degree of apical closure and radiographic root area changes were compared with those of the last follow-up in this retrospective study. Radiographic root area changes were calculated as the difference between the total root and total canal areas.

RESULTS

Fifty-eight patients (81 teeth) underwent regenerative endodontic treatment during the study period, of whom 32 patients (36 teeth, 62%) were included. The survival and success rates of the treated teeth were 100% and 94.4%, respectively. All teeth developed a calcific bridge in the cervical third of the root canal, indicating the presence of vital tissue. Apical narrowing (partial or total) was observed in 75% of the cases. The root maturation stage affected the percentage increase in the radiographic root area. Teeth in Cvek stages II-III showed a higher radiographic root area increase than more mature teeth. All tooth radiographic root areas increased significantly in the initial 20 months of the treatment and moderately thereafter.

CONCLUSIONS

Regenerative endodontic treatment is a safe approach for traumatised immature teeth. The presence of a radiographic calcified bridge may be an early indication of treatment success. The main complete tooth morphological changes occur after approximately 20 months posttreatment. These findings may help clinicians better understand the time-dependent changes in the root morphology after treatment, improve the follow-up schedule and predict the progress of healing during follow-up visits.

Development of a Core Outcome Set for Endodontics (COS-ENDO). Part 5: COS-ENDO for Studies of Apexification and Regenerative Endodontics in Permanent Teeth

INTRODUCTION

Methodological heterogeneity and reporting bias complicate interpreting endodontic outcomes. Supported by the American Association of Endodontists (AAE) and its Foundation, this study developed the Core Outcome Set in Endodontics (COS-ENDO) to standardize reporting for studies of Nonsurgical Root Canal Treatment/Retreatment, Surgical Endodontics, Vital Pulp Therapy, Apexification, and Regenerative Endodontics. This manuscript, the last in a 5-part series, focuses on COS-ENDO for Apexification and Regenerative Endodontics, while other parts address the remaining treatments.

METHODS

Outcomes were identified through scoping reviews and a web-based survey of AAE practicing members. In a two-round Delphi survey, clinicians, patients, and researchers rated outcomes on a 9-point scale. Ratings were assessed against consensus criteria, and a virtual meeting finalized COS-ENDO.

RESULTS

Of the 97 invited participants to Round 1, 77 registered, and 73 (24 Academicians/Researchers, 26 Clinicians, and 23 Patients or their parents/caregivers) assessed 51 outcomes, with 18 excluded. The remaining outcomes-7 achieving consensus for inclusion and 26 lacking consensus-advanced to Round 2 for re-rating by 70 participants. This resulted in 14 outcome achieving consensus for inclusion, and 19 lacking consensus. In the final meeting, 16 participants finalized the COS-ENDO for Apexification and Regenerative Endodontics, including Tooth survival, Pain, Signs of infection, Radiographic evidence of periradicular healing, Continued root development, Success, Functional tooth, Need for further intervention, and Adverse events/Complications.

CONCLUSION

COS-ENDO is an important step in standardizing outcome reporting in endodontics, ensuring consistent reporting and enhancing research utility. Further efforts are needed to establish optimal measurement methods.

Evaluation of the effect of different irrigation solutions used in regenerative endodontic treatment of necrotic molar teeth with open apex on postoperative pain- randomized clinical trial

OBJECTIVES

This study evaluates the effect of different irrigation solutions for postoperative pain in the regenerative endodontic treatments (RET) of necrotic teeth with open apex.

MATERIALS AND METHODS

This study included necrotic, deeply carious lower molars of 42 patients. Access cavities of the teeth were opened and working lengths were measured at the first visit. In Group 1, the root canals were irrigated with 1.5% sodium hypochlorite (NaOCl) and 17% Ethylenediaminetetraacetic-acid (EDTA), in Group 2, with 1.5% NaOCl and 10% citric acid, and in the Group 3, with 1.5% NaOCl and 9% Etidronic acid (HEDP) mixture solution. Final irrigation was performed with distilled water. The canals were dried, filled with calcium hydroxide paste, and sealed with Cavit. Postoperative pain was assessed using a numerical rating scale, and Paracetamol was prescribed. At the second visit, calcium hydroxide was removed with 1.5% NaOCl, irrigated with chelators, and sealed with Sure-Seal PT 3 mm below the cementoenamel junction before composite resin filling.

RESULTS

Postoperative pain was higher in Group 3 (p < 0.05), but analgesic consumption did not show a significant difference (p > 0.05).

CONCLUSIONS

HEDP caused significantly more postoperative pain than EDTA and citric acid (p < 0.05). While the study provided information regarding the effects of irrigation solutions on postoperative pain, further research is needed as it did not include detailed assessments of long-term periapical healing and apex closure.

CLINICAL RELEVANCE

When HEDP is used as a chelation agent in RETs, it shows a higher degree of postoperative pain than EDTA and citric acid solutions.

CLINICAL TRIAL REGISTRATION

The study protocol was registered at www.

CLINICALTRIALS

gov (ID: NCT06386991).

Regenerative endodontic treatment and traumatic dental injuries

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.

Mahidol Study 2: Treatment Outcomes and Prognostic Factors of Regenerative Endodontic Procedures in Immature Permanent Teeth

INTRODUCTION

Studies on the clinical outcomes and prognostic factors of regenerative endodontic procedures (REPs) in a large population and long-term recall period have been limited. Therefore, the aims of this study were to evaluate treatment outcomes and prognostic factors of REPs.

METHODS

Immature permanent teeth treated with REPs with a minimum one-year follow-up period were included. Treatment outcomes (functional retention, healed rate, root development, and sensibility test response) and any prognostic factors were analyzed with multivariable Cox regression, linear regression, and modified Poisson regression.

RESULTS

One-hundred-twenty REPs teeth with a mean 41.7-month recall period were included with a functional retention rate of 97.5%. The healed, healing, and diseased rates of REPs were 80%, 9.2%, and 10.8%, respectively. Significant prognostic factors for healed were age (<12 years old) and root development stage (stages 4 and 5). Changes in the apical diameter, root length, root width, and radiographic root area after REPs were 56.8%, 8.3%, 23.2%, and 21.7%, respectively. Significant prognostic factors for continued root developmevnt were age and etiology of pulpal disease (from caries or dental anomalies). The sensibility test response rate was 41.7% with significant positive factors of ethylenediaminetetraacetic acid irrigation and capping material level above the cemento-enamel junction.

CONCLUSION

REPs demonstrated high functional retention and healed rates. Patients <12 years old presented a higher healed rate and continued root development (excluding root length). Dental caries or anomalies had higher continued root development compared with dental trauma. The sensibility test response was related to ethylenediaminetetraacetic acid irrigation and level capping material.

Radiographic Evaluation of Regenerative Endodontic Procedures and Apexification Treatments with the Assessment of External Root Resorption

INTRODUCTION

This multicentered cohort study evaluated the radiographic outcomes of regenerative endodontic procedures (REPs) and apexification treatments (APEX) of immature teeth with endodontic disease.

MATERIALS AND METHODS

This cohort study included a retrospective record review and prospective data collection of pediatric patients with teeth treated with REPs or APEX between 2005 and 2014. Data including the presence of a periapical lesion, external root resorption, obliteration, apical hard tissue, apical closure, intracanal calcifications, and radiographic root area (RRA) change based on measurements were collected/measured from radiographic images. Univariate and multivariate analyses were conducted.

RESULTS

The cohort included 190 subjects (204 teeth (92 REPs; 112 APEX)). The frequency of pretreatment periapical pathology was similar between cases in which the clinical treatment failed versus successful treatment cases. However, the frequency of pretreatment external root resorption was higher in failed cases than in successful cases (P = .007). The mean RRA change was greater than twenty percent in 21% of the REPs cases. In traumatized teeth, REPs resulted in less hard tissue formation than other endodontic disease etiologies measured by RRA (P = .001). Fifty-three percent of cases with ERR (16/30) showed signs of healing/arrest and were mostly treated with REPs (11/16).

CONCLUSIONS

The presence of ERR negatively affected the treatment outcome. There was significant variability in RRA change in REPs. Signs of healing/arrest of the resorptive lesion were radiographically visible in many cases treated with REPs.

Impact of using single-file reciprocating system on the quality of root canal treatment treated by undergraduate students

Background

This study aimed to evaluate the use of a single-file reciprocating system on the technical quality of root canal filling and treatment by radiographic assessment of cases treated by undergraduate dental students.

Materials and methods

This was a retrospective cross-sectional clinical study of endodontically treatments conducted by fourth-year undergraduate students during the academic year 2021-2022. Root canal preparation was performed using the WaveOne Gold system with matching single-cone gutta-percha. The collected data included sex, tooth position, number of canals, and treatment time (first or second semester). The quality of the root canal filling was assessed based on the root canal filling length, density, and taper. The presence of ledges, apical transportation, perforation, and instrument separation were recorded. Data were analyzed using SPSS version 28. Chi-square tests were used, and the statistical significance level was set at P < 0.05.

Results

A total of 601 teeth were included. The length of the root canal filling was adequate in 93.51 % of the teeth, underfilled in 2.82 %, and overfilled in 3.66 %. The density and taper were adequate in 96.5 % and 98.16 % of the teeth, respectively. There were no significant differences among the parameters of length, taper, density, or procedural errors relative to the arch type. However, there was a significant difference between the anterior and premolar teeth in terms of taper, density, and overall quality of the root canal filling. The overall quality of root canal treatment was acceptable in 527 teeth (87.68 %), with no significant difference between teeth (P = 0.256).

Conclusion

The quality of root canal treatment performed by undergraduate students using a single-file reciprocating system is good or acceptable.

Endodontic characteristics of mandibular premolar with dens evaginatus: a retrospective study

Objectives

This study aimed to investigate the endodontic characteristics of mandibular premolars with dens evaginatus (DE) that require endodontic treatment.

Materials and Methods

Patients who underwent endodontic treatment were enrolled. The inclusion criteria were patients who underwent root canal treatment in the lower permanent teeth with DE and were followed up for at least 1 year. Preoperative clinical and radiographic variables were obtained. The frequency distribution of the preoperative variables was compared using the χ2 or Fisher's exact tests. The significance of the change in periapical health index (PAI) and root development stages before and after treatment was examined using the Wilcoxon signed-rank test.

Results

A total of 150 teeth of 134 patients with an average age of 15.3 years were included. The percentage distribution comparison of the preoperative variables and obturation techniques revealed significant differences in pulpal and periapical diagnosis, and percussion, and especially regarding age, root development stage, and PAI. Age was the only statistically significant preoperative variable associated with root growth (p < 0.05).

Conclusions

Approximately, 60% of DEs requiring endodontic treatment had immature roots. Age being the most significant predisposing factor, early treatment provides the greatest opportunity for full root development.

Regenerative endodontic therapy: From laboratory bench to clinical practice

BACKGROUND

Maintaining the vitality and functionality of dental pulp is paramount for tooth integrity, longevity, and homeostasis. Aiming to treat irreversible pulpitis and necrosis, there has been a paradigm shift from conventional root canal treatment towards regenerative endodontic therapy.

AIM OF REVIEW

This extensive and multipart review presents crucial laboratory and practical issues related to pulp-dentin complex regeneration aimed towards advancing clinical translation of regenerative endodontic therapy and enhancing human life quality.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this multipart review paper, we first present a panorama of emerging potential tissue engineering strategies for pulp-dentin complex regeneration from cell transplantation and cell homing perspectives, emphasizing the critical regenerative components of stem cells, biomaterials, and conducive microenvironments. Then, this review provides details about current clinically practiced pulp regenerative/reparative approaches, including direct pulp capping and root revascularization, with a specific focus on the remaining hurdles and bright prospects in developing such therapies. Next, special attention was devoted to discussing the innovative biomimetic perspectives opened in establishing functional tissues by employing exosomes and cell aggregates, which will benefit the clinical translation of dental pulp engineering protocols. Finally, we summarize careful consideration that should be given to basic research and clinical applications of regenerative endodontics. In particular, this review article highlights significant challenges associated with residual infection and inflammation and identifies future insightful directions in creating antibacterial and immunomodulatory microenvironments so that clinicians and researchers can comprehensively understand crucial clinical aspects of regenerative endodontic procedures.

Cost-Effectiveness Analysis of Regenerative Endodontics versus MTA Apexification

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.

Pulp regeneration treatment using different bioactive materials in permanent teeth of pediatric subjects

Background and Objectives

The present systematic review aims to assess the success rate of the pulp regeneration treatment, according to the American Association of Endodontists (AAE) criteria, using different bioactive materials in permanent teeth of pediatric subjects (6-17 years of age).

Materials and Methods

The study protocol was registered on PROSPERO and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. The question formulation was accomplished using the PICO model, and an electronic search was carried out on Scopus, MEDLINE/PubMed, Web of Science, and Cochrane databases till April 1, 2023. A total of 30 studies were established to fulfill the inclusion criteria of this systematic review.

Results

A total of 273 teeth have been treated with pulp regeneration treatment. By comparing different biomaterials and the success criteria defined by the AAE, the material associated with a higher success rate was found to be the white mineral trioxide aggregate. However, the overall success rate of pulp regeneration treatment was reported for 248 out of 273 teeth (91.20%).

Conclusions

Data obtained support the potential that regenerative endodontics aids in continuing root development in permanent immature teeth. Further studies are needed for a more extensive evaluation of the use of different biomaterials and the success rate in regenerative endodontics.

Treatment outcomes of regenerative endodontic therapy in immature permanent teeth with pulpal necrosis: A systematic review and network meta-analysis

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.

Discoloration after revascularization using calcium phosphosilicate-based bioceramic versus mineral trioxide aggregate in necrotic immature permanent anterior teeth: A Randomized clinical trial

Aim

The aim of the current study is to evaluate the effect of calcium phophosilicate-based bioceramic "Totalfill bioceramic putty" and white mineral trioxide aggregate (WMTA) as the coronal plug on discoloration after revascularization of necrotic immature permanent anterior teeth.

Materials and Methods

This study was conducted on (48) necrotic young permanent central incisors in children ranging from 8 to 14 years old, that were randomly allocated to either Totalfill bioceramic (Group I = 24) or WMTA (Group II = 24) as the coronal plug. Two visits revascularization protocol was adopted in this study using 1.5% sodium hypochlorite, followed by 17% ethylenediaminetetraacetic acid, and ending with a saline flush as irrigation solution. The double antibiotic paste was used as intracanal medication. The blood clot was used as scaffold followed by the application of collagen membrane followed by coronal plud malterial. Finally, the access was sealed using resin composite restoration and composite restoration. Clinical assessment was conducted at 1, 3, 6, 9, and 12 months, while radiographic assessment was conducted at 6 and 12 months. Data were statistically analyzed using the Chi-squared test for intergroup comparisons and Cochran's Q test for intragroup comparison.

Results

Clinically, Group I exhibited a success rate of 100%, whereas Group II exhibited a success rate of 85.7%. Radiographically, both materials showed a 90.5% success rate. There was no statistically significant difference between both materials for all assessed clinical and radiographic parameters at different follow-up periods.

Conclusions

Both Totalfill bioceramic putty and WMTA can be used successfully as coronal plug in esthetic areas.

Clinical, Radiographic, and Histologic Outcomes of Regenerative Endodontic Treatment in Human Immature Teeth Using Different Biological Scaffolds: A Systematic Review and Meta-analysis

BACKGROUND

Biological scaffolds such as blood clot (BC), platelet-rich plasma (PRP), platelet- rich fibrin (PRF), and platelet pellet (PP) are used in regenerative endodontic treatments (RETs).

OBJECTIVE

To systematically and quantitatively evaluate clinical, radiographic, and histologic outcomes of RET studies using different biological scaffolds.

METHODS

MEDLINE, Scopus, Cochrane library, and Embase were searched to identify studies on RET procedures with any scaffold type performed on immature non-vital human teeth, employing any type of biological scaffold. Clinical, radiographic, and histologic outcomes were extracted. Cochrane collaboration risk of bias tool and Newcastle-Ottawa scale were used for quality assessment. Random and fixed model meta-analysis was carried out with 95% confidence interval.

RESULTS

Thirty-two studies were included in the qualitative analysis from the primarily retrieved 1895 studies. Only one study had high risk of bias and 71.8% of the studies had high quality. None of the studies reported any histologic findings. Thirty studies were included in meta-analysis. Clinical success rate of RET using either BC, PRP, or PRF was >99%. Furthermore, 32%, 23%, and 27% of BC, PRP, and PRF cases regained vitality, respectively. Periapical healing was seen in 67%, 75%, and 100% of BC, PRP, and PRF cases, respectively. There was no statistical difference between BC, PRP, or PRF regarding clinical success or any radiographic outcomes.

CONCLUSION

There was no significant difference between BC, PRP, and PRF in terms of clinical and radiographic outcomes. When it is difficult or dangerous to induce bleeding in root canals, PRP and PRF may be employed instead.

Treatment outcomes of immature permanent necrotic evaginated teeth: A retrospective study comparing regenerative endodontic procedures with apexification

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.

Biomechanical characterization of a fibrinogen-blood hydrogel for human dental pulp regeneration

In dental practice, Regenerative Endodontic Treatment (RET) is applied as an alternative to classical endodontic treatments of immature necrotic teeth. This procedure, also known as dental pulp revitalization, relies on the formation of a blood clot inside the root canal leading to the formation of a reparative vascularized tissue similar to dental pulp, which would provide vitality to the affected tooth. Despite the benefit of this technique, it lacks reproducibility due to the fast degradation and poor mechanical properties of blood clots. This work presents a method for constructing a fibrinogen-blood hydrogel that mimics the viscoelastic properties of human dental pulp while preserving the biological properties of blood for application in RET. By varying the blood and fibrinogen concentrations, gels with different biomechanical and biological properties were obtained. Rheology and atomic force microscopy (AFM) were combined to study the viscoelastic properties. AFM was used to evaluate the elasticity of human dental pulp. The degradation and swelling rates were assessed by measuring weight changes. The biomimetic properties of the gels were demonstrated by studying the cell survival and proliferation of dental pulp cells (DPCs) for 14 days. The formation of an extracellular matrix (ECM) was assessed by multiphoton microscopy (MPM). The angiogenic potential was evaluated by an ex vivo aortic ring assay, in which the endothelial cells were observed by histological staining after migration. The results show that the Fbg-blood gel prepared with 9 mg ml-1 fibrinogen and 50% blood of the Fbg solution volume has similar elasticity to human dental pulp and adequate degradation and swelling rates. It also allows cell survival and ECM secretion and enhances endothelial cell migration and formation of neovessel-like structures.

Effectiveness of revitalization in treating apical periodontitis: A systematic review and meta-analysis

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.

Regenerative Therapy for the Permanent Immature Teeth: A Long Term Study. An Original Research

Introduction

Endodontics faces several clinical difficulties while treating young necrotic permanent teeth. The use of regenerative endodontic procedures (REPs) enables apical closure, improved canal wall thickness, and root growth. The objective of this study was to assess the effects of these regenerative procedures on immature necrotic permanent teeth.

Methods

This prospective clinical study was conducted at the tertiary care hospital for the study period of 2 years. This study includes 30 necrotic permanent immature teeth that were studied in 30 subjects of both genders. A standard REP protocol was used to treat every tooth. A follow-up visit was scheduled for each patient at timely intervals. Various study parameters as well as the demographics were assessed at each visit. To examine various parameters, a calibrated endodontist also performed a radiographic evaluation.

Results

Our findings point to excellent rates of survival, clinical success, and apical pathological resolution for 29 teeth. After 2 years, there were significant variations in the root thickness area and the average root length. The apical diameter significantly decreased during the research period, with 30.8% of the instances exhibiting full apical closure. Apical diameter, root length, and thickness changed more frequently in teeth with the level of the immaturity of the root, although the variations were not significant.

Conclusions

REP treatment for teeth preceded symptom relief. Increased root thickness, root length, and apical closure were seen at 30 months, even if the clinically meaningful change was not attained in all patients.

Is Etiology a Key Factor for Regenerative Endodontic Treatment Outcomes?

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 to 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<0.05), whereas there was no significant difference in the percentage changes of root length, root width and apical diameter between the two 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.

Outcome of Regenerative Endodontic Procedures in Non-Vital Immature Permanent Teeth Using Two Intracanal Medications: A Prospective Randomized Clinical Study

INTRODUCTION

This randomized clinical trial aimed to assess and compare the long-term clinical and radiographic outcomes of Regenerative Endodontic Procedures (REP) in treating non-vital immature permanent teeth using two intra-canal medicaments.

METHODS

Forty-five patients yielding a total of 50 anterior and posterior non-vital immature teeth were randomly divided into 2 groups. REP utilizing either non-setting calcium hydroxide (Ca(OH)₂) (n=25) or modified triple antibiotic paste (TAP) (n=25), as intra-canal medicaments were performed. NeoMTA Plus (Avalon Biomed Inc™, Houston, Texas, USA) was applied for coronal sealing. Cases were followed up clinically and radiographically for 36 months. Survival rate, success rate, and clinical outcome measures were analyzed. Preoperative and recall radiographs were evaluated for dimensional changes in root length, dentin thickness, apical diameter, and periapical radiolucency.

RESULTS

At 36 months follow up, success and survival rates were 81.6%, and 100% respectively, in which 79.4% of cases showed complete resolution of periapical radiolucency, with no significant difference between non-setting Ca(OH)2 and modified TAP groups (P>0.050). The cumulative changes in root length, root dentin thickness and apical diameter, throughout the study period, were observed in 47.9%, 77.1%, and 89.6 %, of cases respectively, with no significant differences between both groups (P≥ 0.39). Intra-canal calcifications were detected in 60% of cases with no significant difference between both groups (P=0.77).

CONCLUSIONS

REP, using either non-setting Ca(OH)₂ or modified TAP as intra-canal medicament, exhibited high success and survival rates, over a follow up period of 36 months, with equally favorable clinical and radiographic outcome data.

The influence of calcium silicate-based cement on osseous healing: A systematic review and meta-analysis

Objectives

The purpose of this systematic review was to analyze the effect of commercially available calcium silicate-based bioactive endodontic cement (BEC) on treatment outcome when used as root repair material in human permanent teeth and to compare it with traditional materials.

Methods

PubMed, Embase, and Cochrane Library were searched until June 2020. Randomized clinical studies and observational studies with a minimum 1-year follow-up and sample size of at least 20 were included. Risk of bias (ROB) was assessed using Cochrane's ROB tool and the National Institutes of Health Quality Assessment Tool.

Results

Thirty-nine studies were included in the systematic review. Majority of the studies used mineral trioxide aggregate. The pooled success rate for BEC was estimated by a random-effects method as 90.49% (95% confidence interval [CI]: 88.4992.34, I2 = 54%). Eleven studies comparing BEC with traditional materials were included in the meta-analysis. The use of BEC significantly improved the treatment outcome when compared to traditional materials with odds ratio (OR) = 2.15 (95% CI: 1.57-2.96, I2 = 0.8%, P = 0.433).

Conclusion

Very low-to-moderate-quality evidence suggests that the use of BEC as root repair material enhanced the treatment outcome. High-quality studies are required for the newer BEC to establish their clinical performance. Registration: PROSPERO CRD42020211502.

Endodontic management strategies for permanent teeth with immature apices

This article will provide a summary of causes of incomplete root end closure and the implications of this on endodontic treatment. The limitations and benefits of traditional and more contemporary materials including the use of bioceramic cements are considered. The apical barrier technique is described in detail for teeth with immature apices utilising a variety of bioceramic cements and regenerative endodontic procedures with an overview of appropriate instruments to successfully complete the procedure.

Influence of ethylenediaminetetraacetic acid irrigation on the regenerative endodontic procedure in an immature rat molar model

AIM

To analyse the influence of ethylenediaminetetraacetic acid (EDTA) on the repair process in immature rat molars after a regenerative endodontic procedure (REP).

METHODOLOGY

The lower first molars of 12 4-week-old Wistar rats underwent pulpectomy in the mesial root and were divided into the following groups: sodium hypochlorite (NaOCl; n = 6) - the mesial canals were irrigated with 2.5% NaOCl for 5 min, and NaOCl-EDTA (n = 6) - the canals were irrigated with 2.5% NaOCl, followed by 17% EDTA for 5 min each. After evoking bleeding using a size 10 K-file, the cavities were sealed. Three molars on the untreated side were randomly used as control (control-15 d; n = 3), and three molars from the other three rats untreated were used as immediate control (n = 3). After 15 days (NaOCl, NaOCl-EDTA and control-15 d groups) or immediately (control-immediate), the animals were euthanized, and the teeth were subjected to histologic evaluation of tissue regeneration and presence of collagen fibres. Mann-Whitney U-test was used (p < .05).

RESULTS

The experimental groups had newly formed cementum-like tissue and increased root length and thickness. Half of the specimens in NaOCl-EDTA group showed apical foramen closure, whilst the NaOCl group had partial apical closure. The experimental groups showed inflammatory infiltrate extending mainly to the medium third of the root canal. These parameters were similar between experimental groups (p > .05). Newly formed connective tissue in the pulp space was significantly higher in the NaOCl-EDTA group than in NaOCl group (p < .05). Regarding the collagen fibres, the NaOCl-EDTA group had more collagen fibres in the root tip, but there was no significant difference compared to NaOCl group, and both groups showed greater amount of immature fibres in this area; in the centre of the apical third of root canal, there was equivalence between mature and immature fibres from both groups (p > .05).

CONCLUSIONS

Ethylenediaminetetraacetic acid irrigation improved newly formed intracanal connective tissue after REP in immature molars of rats; however, EDTA did not influence cementum-like tissue formation, apical closure, inflammatory infiltrate and maturation of collagen fibres.

Modified pulpotomy procedure in immature permanent teeth with apical periodontitis: a randomised controlled trial

OBJECTIVES

The objective of this study was to evaluate the effectiveness of a modified pulpotomy (MP) procedure in immature permanent teeth with apical periodontitis (AP).

DESIGN

Randomised controlled trial.

SETTING

One public hospital in Shanghai, China PARTICIPANTS: A total of 33 teeth (31 patients) with a definitive diagnosis of AP with radiographic periapical radiolucency were recruited in this study. All the patients (teeth) completed the study accordingly.

METHODS AND INTERVENTION

Patients were randomly assigned to either MP or apexification treatment groups and were followed up for 12 months. Clinical symptoms and complications were recorded, and parallel periapical radiographic images were used to measure changes in root length and apical diameter. Wilcoxon's rank sum test and Fisher's exact test were used to compare the clinical and radiographic outcomes between MP and apexification, and analysed with analysis of variance.

MAIN OUTCOME MEASURE

The primary outcome was increase in root length at 12 months. The secondary outcomes included tooth survival, clinical success and decrease in apical diameter.

RESULTS

MP group showed a significant increase in root length (10.05%±2.14% vs 1.16%±0.79%, p<0.05) at 12 months and a decrease in apical diameter (48.88%±10.42% vs 15.90%±8.88%, p<0.05) as compared with the apexification group. The tooth survival rate was 100%, and 90.91% (30/33) of teeth were asymptomatic with apical healing in both treatment groups (p>0.05).

CONCLUSIONS

MP can be an option for treating immature permanent teeth with AP. MP showed better performance in terms of continued root maturation than apexification. MP and apexification achieved comparable outcomes with regard to the resolution of clinical symptoms and apical healing.

TRIAL REGISTRATION NUMBER

ChiCTR-INR-17012169.

Evaluation of the characteristics of root canal calcification after regenerative endodontic procedures: A retrospective cohort study over 3 years

AIM

This study aimed to evaluate the characteristics of root canal calcification after regenerative endodontic procedures (REPs) during long-term follow-up.

DESIGN

Data of children who underwent REPs and were followed up for >3 years in the Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, Beijing, China, from January 2013 to January 2019, were collected. All the patients were treated by the protocol of REPs based on the American Association of Endodontists (AAE) protocol. A total of 91 teeth of 54 boys and 37 girls (average age 10.4 ± 1.9 years) with follow-up duration >3 years were included. The follow-up duration ranged from 36 to 92 months (average, 53.2 ± 13.4 months). The prevalence, contributing factors, and long-term prognoses of root canal calcification after REPs are discussed. Independent t-test and χ² test were used for statistical analysis.

RESULTS

The incidence of root canal calcification was 78% (71/91). The use of calcium hydroxide paste was significantly correlated with the occurrence of root canal calcification (p < .05). Some teeth showed aggravation of calcification with time; however, not all teeth showed calcification after longer follow-up duration.

CONCLUSIONS

Teeth treated with REPs had a relatively high probability of root canal calcification detection during the long-term follow-up. The occurrence of calcification is related to the use of calcium hydroxide paste but does not affect the long-term prognosis of teeth.

Biomimetic Approaches in Clinical Endodontics

In the last few decades, biomimetic concepts have been widely adopted in various biomedical fields, including clinical dentistry. Endodontics is an important sub-branch of dentistry which deals with the different conditions of pulp to prevent tooth loss. Traditionally, common procedures, namely pulp capping, root canal treatment, apexification, and apexigonesis, have been considered for the treatment of different pulp conditions using selected materials. However, clinically to regenerate dental pulp, tissue engineering has been advocated as a feasible approach. Currently, new trends are emerging in terms of regenerative endodontics which have led to the replacement of diseased and non-vital teeth into the functional and healthy dentine-pulp complex. Root- canal therapy is the standard management option when dental pulp is damaged irreversibly. This treatment modality involves soft-tissue removal and then filling that gap through the obturation technique with a synthetic material. The formation of tubular dentine and pulp-like tissue formation occurs when stem cells are transplanted into the root canal with an appropriate scaffold material. To sum up tissue engineering approach includes three components: (1) scaffold, (2) differentiation, growth, and factors, and (3) the recruitment of stem cells within the pulp or from the periapical region. The aim of this paper is to thoroughly review and discuss various pulp-regenerative approaches and materials used in regenerative endodontics which may highlight the current trends and future research prospects in this particular area.

Assessment of bone quality of apical periodontitis treated with MTA plug and regenerative endodontic techniques

Fractal analysis (FA) is a quantitative, objective and non-invasive method that facilitates the characterisation of the tissue architecture. This study aims to compare the periapical healing at 1-year follow-up by evaluating newly generated trabecular bone with FA after Mineral trioxide aggregate (MTA) plug and regenerative endodontic treatment (RET). A total of 55 asymptomatic teeth with a single-canal, open apex and periapical lesion, treated with MTA plug or RET, were evaluated retrospectively. After considering the inclusion/exclusion criteria, FA was conducted on 30 periapical images using the box-counting method. In both groups, a significant decrease was observed in the periapical lesion size at 1-year follow-up (p < 0.01). However, there was no significant difference between the MTA plug and RET (p > 0.01). Significantly higher fractal dimension values were detected at 1-year follow-up in both MTA plug and RET cases (p < 0.01). However, the difference was not significant between the groups (p > 0.01). Both procedures seem to improve periapical healing with a new resistant bone of similar density and complexity.

Preoperative factors analysis on root development after regenerative endodontic procedures: a retrospective study

Background

Regenerative endodontic procedures (REPs) have achieved clinical success on the immature permanent teeth with pulp necrosis, and can promote root development. However, preoperative factors and their effects on root development of REPs have not been definitely concluded. The aim of this study was to investigate the preoperative factors that may influence the root development of REPs.

Methods

A total of 116 teeth in 110 patients treated with REPs in the Paediatric Dentistry Department and Endodontics Department from 2013 to 2017 were included in this study. Preoperative factors including aetiology, age, diagnosis and initial root morphology were collected retrospectively, and the associations between these factors and root development after REPs were analysed by Fisher's exact test and multivariate logistic regression model.

Results

The overall rate of root development after REPs was 89.7%. The dens evaginatus group showed a higher rate (98.8%) in root development than the trauma group (67.6%) (P < 0.01). There was no significant difference among the different age groups (7–13 years old) or among different diagnoses groups (P > 0.05). And it showed in the trauma group that the teeth with apical foramen sizes larger than 3 mm significantly promoted root development than those smaller than 3 mm (P < 0.01). Multivariate logistic regression indicated that aetiology was significantly correlated with root development of REPs (OR: 0.07, 95% CI 0.007, 0.627, P < 0.05).

Conclusions

The REPs promoted more root developments in the dens evaginatus group than the trauma group, indicating that aetiology may be correlated with the root development of REPs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02412-x.

Effect of Duration of Root Canal Infection on the Ability of Dentin-Pulp Complex Regeneration of Immature Permanent Teeth: An Animal Study

BACKGROUND

Persistent infection is always considered the most important reason for the failure of dentin-pulp complex regeneration. The present study aims to evaluate the effect of the duration of root canal infection (from one to twelve weeks) on the ability of dentin-pulp complex regeneration.

METHODS

In this animal study, 64 roots of immature premolar teeth of four dogs were randomly divided into four groups. Positive control group; eight root canals treated with regenerative endodontic procedure (REP), negative control group; 12 infected root canals, intervention groups; 36 root canals infected with supragingival plaque (one, three, six, and 12 weeks) and treated with REP, an additional positive control group; eight normal roots. After three months, the teeth were investigated by radiographic images and immunohistochemical staining (CD31, CD34, S100 markers). In addition, DSPP gene expression was assessed using a real-time PCR technique. The results were analyzed at a significance level of 0.05.

RESULTS

Based on radiological evaluation among the intervention groups, the highest root canal development (length and width) occurred in the intervention group of one week, and the lowest radiological results were in the intervention groups of six and 12 weeks (One-way ANOVA, P <0.05). There was a significant difference between the groups in terms of CD31, CD34, S100 and, DSPP expression percentage (One-way ANOVA, P <0.05), in which the highest and lowest expression percentages belonged to the one- and 12 weeks groups, respectively, among the intervention groups.

CONCLUSION

This study demonstrated that long root canal infection decreased the ability of the body to regenerate dentin-pulp complex.

Clinical Outcome and Comparison of Regenerative and Apexification Intervention in Young Immature Necrotic Teeth-A Systematic Review and Meta-Analysis

This systematic review aimed to evaluate interventions individually and compare the clinical outcome of young, immature teeth treated with regenerative endodontic therapy (RET) and apexification procedure. The protocol was registered with PROSPERO (International Prospective Register of Systematic Reviews), bearing the registration number CRD42021230284. A bibliographic search in the biomedical databases was conducted in four databases—PubMed, CENTRAL, EMBASE and ProQuest—using searching keywords and was limited to studies published between January 2000 and April 2022 in English. The search was supplemented by manual searching, citation screening and scanning of all reference lists of selected paper. The study selection criteria were randomized clinical trial, prospective clinical studies and observational studies. The search found 32 eligible articles, which were included in the study. The quality assessment of the studies was performed using the Cochrane risk of bias tool for randomized control trials and non-randomized clinical studies. The meta-analysis was performed using Review Manager software (REVMAN, version 5). The results indicated that a clinicians’ MTA apexification procedure was more successful compared to calcium hydroxide. In RET, apical closure and overall success rate is statistically same for both apical platelet concentrates (APCs) and blood clots (BC). Both interventions have similar survival rates; however, RET should be preferred in cases where the root development is severely deficient, there is insufficient dentine and the tooth’s prognosis is hopeless even with an apexification procedure.

Endodontic pulp revitalization in traumatized necrotic immature permanent incisors: Early failures and long-term outcomes-A longitudinal cohort study

AIM

This prospective cohort study evaluates clinical and radiographical outcomes of endodontic pulp revitalization (PR) of traumatized necrotic incisors.

METHODOLOGY

Pulp revitalization was performed in 75 traumatized necrotic immature incisors from 71 patients. The radiographic outcome measures were continued root formation (width and length), root resorption, apex closure, periapical index, and root development stage. The clinical outcome measures were percussion pain, palpation pain, pathological tooth mobility, swelling, sinus tract, ankylosis, crown discolouration, response to pulp sensitivity test, and subjective pain. Treatment outcomes were categorized as a success based on the absence of clinical symptoms and when radiographic evidence was present for apical healing and continued root development. The performed statistical tests were repeated measures anova, pairwise comparisons of interactions (t-test), McNemar's test, and linear regression model.

RESULTS

In 45 of 75 teeth (60%), PR was successful with the resolution of clinical and radiographic signs and continued root development. PR failed due to the absence of bleeding (n = 19) and persistent infection (n = 11). PR showed statistically significant increases in root length (11%), and dentinal wall thickness (30%), root maturation (pre-operative 3.38 [CI 1.88; 4.88]; post-operative 4.04, [CI 2.56; 5.52]) apical closure (71.4%), healing of pre-operative apical periodontitis (100%), and healing of pre-operative inflammatory root resorptions (100%). Three predictive variables for continued root maturation were identified - root development stage at entry (p = .0001, β 0.649), [CI 0.431; 0.867], trauma to the soft tissues (p = .026, β -0.012), [CI -0.0225; -0.015], and pre-operative dentinal wall thickness (p = .009, β -0.001); [CI -0.001; 0.0001].

CONCLUSIONS

Our findings indicate that PR provides satisfactory clinical and radiographical outcomes in traumatized necrotic incisors. The failed cases were related to lack of bleeding and persistent infections, indicating that new techniques are needed to improve the predictability of PR.

Clinical and radiographic outcomes of regenerative endodontic treatment performed by endodontic postgraduate students: a retrospective study

Objectives

Regenerative endodontic treatment is a clinical procedure aimed at biologically regenerating damaged root canal tissue of immature permanent teeth. This study aimed to report the outcomes of regenerative endodontic treatment performed by endodontic postgraduate students.

Materials and Methods

Clinical and radiographic data of 27 patients, aged 10–22 years, who underwent regenerative treatment of immature permanent teeth from 2015 to 2019 were followed up, wherein clinical and radiographic examinations were performed for each patient. Postoperative success rate and tooth survival were analyzed, and the postoperative radiographic root area changes were quantified.

Results

A total of 23 patients attended the dental appointments, showing that all teeth survived and were asymptomatic. Specifically, 7 periapical pathosis cases were completely healed, 12 were incompletely healed, and 4 cases failed. Moreover, significant differences were found between discolored and non-discolored teeth, and between the presence or absence of periapical radiolucency. Additionally, 3 anterior teeth showed complete closure of the apical foramen, while the apical foramen width was reduced in 17 teeth and failed in 3 teeth. Root length was also found to have been increased in 7 anterior and 4 posterior teeth, and the average length ranged from 4.00–0.63 mm in the anterior teeth, 2.85–1.48 mm of the mesial root, and 2.73–2.16 mm of the molar teeth distal root. Furthermore, calcified tissue deposition was observed in 7 teeth.

Conclusions

A favorable outcome of regenerative endodontic treatment of immature permanent teeth with necrotic pulp was achieved with a high survival rate.

A critical analysis of clinical research methods to study regenerative endodontics

Regenerative endodontic treatment such as revitalization provides a treatment option for immature teeth with pulp necrosis. The main difference to the alternative procedure, the apical plug, is the induction of a blood clot inside the canal as a scaffold for healing and new tissue formation. Due to the biology-based and minimally-invasive nature of the treatment, revitalization has raised considerable interest in recent years. Whereas the procedure is fairly new and recommendations from endodontic societies have been in place only for a few years, the treatment protocol has evolved over the past two decades. Evidence has been created, not only from laboratory and animal work, but also from clinical studies including case reports, cohort studies and eventually prospective randomized controlled clinical trials, systematic reviews and meta-analyses. However, the research methods and clinical studies with subsequent reports oftentimes present with methodical limitations, which makes it difficult to objectively assess the value of this treatment modality. Several open questions remain, including the need for a more differentiated indication of revitalization after different traumatic injuries, the long-term prognosis of treated teeth and the true benefits for the patient. Therefore, this review aims to identify and reflect on such limitations, scrutinizing study design, diagnostic tools, procedural details and outcome parameters. A core outcome set is also proposed in this context, which can be considered in future clinical investigations. These considerations may lead to a more detailed and stringent planning and execution of future studies in order to create high-quality evidence for the treatment modality of revitalization and thus provide more robust data, create a larger body of knowledge for clinicians and further specify current recommendations.

Influence of ethylenediaminetetraacetic acid on regenerative endodontics: a systematic review

BACKGROUND

The effects of ethylenediaminetetraacetic acid (EDTA) on regenerative endodontic procedures (REPs) are controversial, because, despite releasing growth factors from dentine, some studies show negative effects on cell behaviour.

OBJECTIVES

To investigate the influence of the use of EDTA in REP on the growth factors' release, cell behaviour, and tissue regeneration.

METHODS

A systematic search was conducted (PubMed/Medline, Scopus, Cochrane Library, Web of Science, Embase, OpenGrey, and reference lists) up to February 2021. Only in vivo and in vitro studies evaluating the effects of EDTA on the biological factors of dentine, pulp/periapical tissues, and cell behaviour were eligible. Studies without a control group or available full text were excluded. The growth factors' release was the primary outcome. Risk of bias in the in vitro and in vivo studies was performed according to Joanna Briggs Institute's Checklist and SYRCLE's RoB tool, respectively.

RESULTS

Of the 1848 articles retrieved, 36 were selected. Among these, 32 were in vitro, three animal studies, and one with both models. The EDTA concentrations ranged from 3%-15%, at different times. Regarding growth factors' release (17 studies), 15 studies found significant transforming growth factor (TGF)-β release after dentine conditioning with EDTA, and most found no influence on vascular endothelial growth factor (VEGF) release. Regarding cell behaviour (26 studies), eight studies showed no influence of EDTA-treated dentine on cell viability; whereas, five, nine, and six studies showed higher cell migration, adhesion, and differentiation, respectively. No influence of EDTA conditioning was observed in animal studies. In vitro studies had a low risk of bias, whereas animal studies had high risk of bias. Meta-analysis was unfeasible.

DISCUSSION

This review found that EDTA increased TGF-β release and improved cell activity. However, well-designed histological analyses using immature teeth models are needed.

CONCLUSIONS

High quality in vitro evidence suggests that EDTA-treated dentine positively influences TGF-β release, cell migration, attachment, and differentiation; further research to evaluate its influence on tissue regeneration is necessary due to low methodological quality of the animal studies.

Intracanal calcification following regenerative endodontic treatment: a systematic review and meta-analysis

OBJECTIVES

Calcification is a common finding in endodontic cases after regenerative endodontic therapy (RET). We aimed to identify the prevalence of intracanal calcification after RET and to compare intracanal calcification outcomes in RET using either calcium hydroxide [Ca(OH)₂] or antibiotics.

MATERIALS AND METHODS

We searched PubMed, Web of Science, ProQuest Dissertations & Theses, and Scopus databases for clinical, cross-sectional, case-control, and cohort RET studies published until May 2020 in the English language and reporting a calcified case after RET. The Cochrane risk-of-bias tool for randomized trials and Risk of Bias In Non-randomized Studies of Interventions were used for bias assessment. Meta-analyses were performed, overall and separately, for intracanal medicaments using a random-effects model with weighted inverse variance methods. Subgroup analysis was performed according to the calcification type.

RESULTS

Eight studies were included. The overall prevalence of intracanal calcification after RET was 30.7% (95% confidence interval [CI]: 0.15-0.45,[Formula: see text]=92.6%), 46.5% with Ca(OH)₂ vs. 25.8% with antibiotic-based intracanal medicaments. Subgroup analyses for complete calcification outcome showed a higher prevalence of complete calcification in the Ca(OH)₂ group (46.5%, 95% CI: 0.17-0.68,[Formula: see text]%) than in the antibiotic group (10%, 95% CI: - 0.04-0.43,[Formula: see text]%).

CONCLUSIONS

Based on the studies included, available evidence shows a statistically significant association between complete calcification and Ca(OH)₂ paste as an intracanal medicament. Other contributing factors, such as blood clot formation and follow-up time, might also play an essential role in forming intracanal calcification.

CLINICAL RELEVANCE

This study highlights the significant association between complete calcification and Ca(OH)₂ paste.

Regenerative Endodontics Success Factors and their Overall Effectiveness: An Umbrella Review

Introduction

Regenerative endodontics is a developing field of dentistry and aims to recover the physiological and anatomical functions of the tooth for cases of severe dental caries, pulpal pathologies and dental trauma.

Materials and Methods

This umbrella review seeks to discover the scientific evidence on the effectiveness and the factors result in successful regenerative endodontic therapies in teeth with necrotic pulps and with incomplete root development. The study was conducted following the PRISMA Guidelines. There were no restrictions regarding search period. A comprehensive literature search was carried out in EMBASE, LILACS, PubMed, Cochrane, Scopus, and Google Scholar. A quality evaluation was conducted by using AMSTAR-2. A descriptive analysis of the included systematic reviews and meta-analysis were conducted.

Results

Thirteen descriptive systematic reviews and 7 meta-analyses were included. Three articles evidenced low methodological quality according to AMSTAR-2 tool. Overall success rates for the endodontic regeneration procedures ranged from 50% to 98% and the survival rates were between 94% and 100%. Pulp regeneration had a high success rate, evidenced by factors such as the resolution of symptoms, healing, increased root length, dentin thickening and recovery of sensitivity. Follow-up varied from 1 to 48 months for the original studies included in the systematic reviews and meta-analyses.

Conclusions

Endodontic practice offers the clinician a good treatment option in case of necrotic pulp with immature roots such as the endodontic regeneration, that is supported by high and moderate quality scientific literature.

Radiographic differences observed following apexification vs revascularization in necrotic immature molars and incisors: a follow-up study of 18 teeth

PURPOSE

To evaluate the effectiveness of apexification versus revascularization in the treatment of necrotic immature teeth and determine which strategy affords the greatest radiological success rate.

METHODS

An analysis was made of 18 teeth subjected to mineral trioxide aggregate (MTA) apical plugging and regenerative endodontic treatment, assessing healing of the apical lesions and the changes in root dimensions.

RESULTS

Significantly greater root growth was observed with revascularization in terms of the percentage change in length (12.75% at 6 months) and dentin thickness (34.57% at 6 months) (p < 0.05). There were no significant differences between the two treatments in terms of the apical healing scores after 6 months of follow-up (p > 0.05).

CONCLUSION

Apexification with an MTA apical plug and pulp regeneration are reliable treatments for non-vital immature teeth. The radiographic outcomes are comparable between the immature teeth subjected to MTA apexification versus those subjected to revascularization. The results of the present study indicate a greater increase in root length and width with regenerative endodontic treatment.

"Meta-analysis of regenerative endodontics outcomes with antibiotics pastes and calcium hydroxide. The apex of the iceberg"

PORPOSE

The aim of this study was to evaluate, through a meta-analysis, the predictability of Regenerative Endodontic therapies with antibiotic pastes and calcium hydroxide [Ca(OH)2], related to four variables as follows: root dentin wall thickening, apical closure, apical repair and root lengthening.

METHODS

Literature electronic searches were performed in Pubmed - MEDLINE, Scopus and Lilacs-BVS platforms using appropriate search terms, Mesh (Medical Subject Headings), DeCS (Health Sciences Descriptors) and Boolean operators comprising articles published between 2009 and 2020. Thirty-two original indexed papers were included making a total of 758 regenerative endodontic procedures. A descriptive meta-analysis was performed.

RESULTS

Dentin wall thickening was present in 66% (CI95: 58%-73%) of the cases treated with antibiotic paste, while when Ca(OH)2 was used, a percentage of 53% (CI95: 26%-78%), was obtained. When antibiotic paste was used, apical closure was found in the 66% (CI95: 58%-73%) of the regenerative endodontic procedures, while when Ca(OH)2 was used, 88% (CI95: 80%-93%) of the cases were found to reach apical closure. Root lengthening and apical repair were found satisfactory for both disinfection protocols.

CONCLUSIONS

There could be differences between the two treatments since a higher percentage of root dentin wall thickening was found when using antibiotic pastes, while a higher percentage of apical closure was found when calcium hydroxide was used. Development of more clinical studies would be necessary in order to confirm the observed differences. The proposed approach could provide a useful contribution for endodontists when planning regenerative endodontic procedures, so as to guide decision-making to the best elective treatment and to select the appropriate disinfection method in accordance with preoperative radiographic diagnosis of root development stage, then increasing the predictability of regenerative endodontic treatment and reducing potential risk of root fractures.

Patient centered outcomes among a cohort receiving regenerative endodontic procedures or apexification treatments

INTRODUCTION

This multi-centered cohort study evaluated factors associated with patient-centered outcomes of immature permanent teeth that received regenerative endodontic procedures (REPs) or apexification treatment (APEX).

METHODS

A record review identified teeth treated with REPs or APEX between September 2005-December 2014. Data regarding treatment and patient-centered outcomes were extracted from records with a 3-month minimum recall. When possible, participants presented for an in-person prospective research visit. Patient-centered success was defined as an asymptomatic, functional tooth, not requiring further endodontic or surgical intervention following completion of the original treatment during the study observation. Risk ratios and adjusted and unadjusted Cox proportional hazard ratios were calculated.

RESULTS

The analytic cohort of 187 individuals included 211 teeth (93 REPs; 118 APEX) with an average follow-up of 32 months. Most cases were successful (81% REPs; 92% APEX) and survived the observation period (96% REPs; 97% APEX). The success rate of REPs was lower than APEX and decreased more rapidly over time. Cox regression analysis demonstrated that when controlling for other variables, the association between treatment type and outcome is not significant. Preoperative infection, teeth with more immature roots, and REPs treatment are potentially important predictors. Among teeth receiving REPs, a lower failure rate was observed for teeth that received multi-antibiotic paste (3/43) compared to calcium hydroxide (11/45).

CONCLUSIONS

Teeth receiving REPs required clinical intervention earlier than teeth that received APEX treatment, although preoperative abscess and more immature root also affected this outcome. Using multi-antibiotic paste versus calcium hydroxide in REPs may improve success.

Decision-Making and Management of Immature Permanent Teeth with Crown Fractures in Small Animals-A Review

Immature permanent teeth with crown fractures present a unique challenge in human and animal patients. Immature permanent teeth have not yet developed completely, often presenting with thin dentin walls, incomplete apical formation, and increased crown-to-root ratios. Loss of pulp function at this stage has devastating long-term implications for these teeth. Ideally, attempts should be made to preserve pulp vitality in immature permanent teeth to allow for continued dental development. The range of treatment options for vital teeth includes odontoplasty with bonding and sealing +/- restoration, indirect pulp capping, and direct pulp capping/vital pulp therapy. These treatments have long been established in human and veterinary medicine, and cases have been reported in dogs and cats. Apexification using calcium hydroxide is a well-established treatment for nonvital immature teeth. The advent of mineral trioxide aggregate and other bioceramic materials for use in vital pulp therapy and apexification has reduced treatment sessions and improved outcomes. Recent developments in the field of regenerative endodontic therapy further expand treatment options and provide the possibility for continued development of a formerly nonvital tooth. Selecting the appropriate treatment based on the severity of tooth fracture and status of pulp vitality can avoid a lifetime of poor structure and function for the affected tooth. This article provides multiple step-by-step protocols for the management of immature permanent teeth with crown fractures in small animals.

Regenerative Endodontic Therapy in the Management of Nonvital Immature Permanent teeth: A Systematic Review and Meta-analysis

This meta-analysis is intended to evaluate the reliability of evidences published in current regenerative endodontic publications in a critical way. This meta-analysis is used to summarize and analyze the various clinical and radiographic findings associated with nonvital immature permanent teeth which have been treated with regenerative endodontic techniques. We also intend to significantly evaluate the worth of facts provided in the previous published literature. A structured electronic search by authors was undertaken in August 2020 using MEDLINE and PubMed search engine. The chosen parameters studied in this systematic review were presented in flowcharts and were summarized. We observed a good accomplishment rates in terms of survival of the treated tooth and also in resolution of any associated pathology in the apical areas; on contrary, our results in relation to apex closure along with constant root development, our findings from various studies were quiet variable. Regenerative endodontic procedures are constantly being restructured and enhanced to benefit present-day dentistry in all likely ways. Still, many factors that are important for the success of regenerative endodontic treatment outcomes still remain unexplained. There are still numerous gaps in our expertise at the present stage of this study.

Roles of Dental Mesenchymal Stem Cells in the Management of Immature Necrotic Permanent Teeth

Dental caries and trauma always lead to pulp necrosis and subsequent root development arrest of young permanent teeth. The traditional treatment, apexification, with the absence of further root formation, results in abnormal root morphology and compromises long-term prognosis. Regeneration endodontics procedures (REPs) have been developed and considered as an alternative strategy for management of immature permanent teeth with pulpal necrosis, including cell-free and cell-based REPs. Cell-free REPs, including revascularization and cell homing with molecules recruiting endogenous mesenchymal stem cells (MSCs), have been widely applied in clinical treatment, showing optimistic periapical lesion healing and continued root development. However, the regenerated pulp-dentin complex is still absent in these cases. Dental MSCs, as one of the essentials of tissue engineering, are vital seed cells in regenerative medicine. Dental MSC-based REPs have presented promising potential with pulp-dentin regeneration in large animal studies and clinical trials via cell transplantation. In the present review, we summarize current understanding of the biological basis of clinical treatments for immature necrotic permanent teeth and the roles of dental MSCs during this process and update the progress of MSC-based REPs in the administration of immature necrotic permanent teeth.

A comparative evaluation of Advanced Platelet-Rich Fibrin (A-PRF) and Platelet-Rich Fibrin (PRF) as a Scaffold in Regenerative Endodontic Treatment of Traumatized Immature Non-vital permanent anterior teeth: A Prospective clinical study

Background

Regenerative endodontic treatment (RET) is a promising treatment alternative for traumatized immature non-vital teeth. Advanced platelet-rich fibrin (A-PRF) contains significantly more growth factors than Platelet-rich fibrin (PRF) and has not been evaluated as a scaffold in RET. The aim of the present study was to evaluate and compare A-PRF and PRF as scaffolds in the RET concerning periapical healing, and root development of traumatized immature non-vital teeth.

Material and Methods

In the present study, RET was performed on 30 traumatized immature non-vital maxillary incisors in 28 patients aged between 8-27 years. Minimal mechanical debridement and irrigation with 1.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid was performed. Canals were disinfected using modified triple antibiotic paste consisting of ciprofloxacin, metronidazole and cefaclor. Based on the type of scaffold, teeth were randomly assigned into A-PRF (n=15) and PRF groups (n=15). Periapical healing, apical response and quantitative root dimensions (length and thickness) were analyzed radiographically after 12 months follow-up.

Results

Nineteen patients with 21 teeth (A-PRF n=11, PRF n=10) completed the follow-up and 9 patients were excluded. Clinically, patients in both the groups were asymptomatic. The survival rates for A-PRF and PRF were 78.5% and 77.5%, respectively. No statistically significant differences were detected between A-PRF and PRF regarding periapical healing and type of apical response (p& 0.05). The difference in the pre-operative and follow-up root thickness and root length in both A-PRF and PRF groups were statistically significant (p< 0.05).

Conclusions

Based on short-term results of 13 months, both A-PRF and PRF can be used as scaffold in regenerative endodontic treatment of traumatized immature non-vital teeth. A-PRF could be recommended in such cases since it yielded more root dentin thickness which is crucial for reinforcing immature teeth.

Key words:Regenerative endodontic treatment, dental trauma, Non-vital teeth, immature teeth, platelet-rich fibrin, advanced platelet-rich fibrin.

Clinical and Radiographic Outcomes of Immature Teeth Treated with Different Treatment Protocols of Regenerative Endodontic Procedures: A Retrospective Cohort Study

Regenerative endodontic procedure (REP) is a progressive treatment modality for immature permanent teeth with necrotic pulp. The ambiguousness about the predictability of REP outcome in relation to complete disinfection of the root canal system and the occurrence of discoloration still exists. The aim of this retrospective study was to analyze two treatment protocols on clinical success rate, radiographic root development and the occurrence of discoloration. Eighteen patients were treated by a single operator by either treatment protocol according to the American Association of Endodontists (AAEP, n = 9) or a modified protocol (MP, n = 9) with the use of 5% sodium hypochlorite and sandblasting. Patients were followed up after 3, 6, 9, 12, 18 and 24 months and clinical success, radiographic root development and the occurrence of discoloration were assessed. The clinical success of MP was significantly higher in two years follow-up (p = 0.015), but the change in radiographic root area was higher for AAEP (p = 0.017) and the occurrence of discoloration was higher in AAEP (p = 0.029). The use of 5% sodium hypochlorite for a longer period of time leads to a higher success rate. The sandblasting of the access cavity reduces the occurrence of discoloration.

The Apical Extent of Mineral Trioxide Aggregate Apical Barrier Does not Influence the Treatment Outcome in a Nonvital Immature Permanent Anterior Tooth: A Split-Mouth Clinical Study

Objective:

The study aimed to compare treatment outcomes when MTA apical plugs are placed to different apical extents in nonvital immature permanent anterior teeth with an open apex.

Methods:

Six participants (five male & one female) between the age group of 8-18 years exhibiting bilateral traumatized nonvital immature permanent maxillary anterior teeth (n=12) with non-blunderbuss canal (Cvek’s stage 4) were included. Standardized endodontic procedures were performed, and an inter-appointment calcium hydroxide medicament placed for one week. Based on the apical position of the MTA apical barrier, two study groups were defined. Accordingly, Group I {(n=6) (4mm MTA plug up to the radiographic root end)} and Group II {(n=6) (4 mm MTA plug 2 mm short of the radiographic root-end)}. Teeth were obturated after twenty-four hours with thermoplasticized gutta-percha technique. They were evaluated clinically and radiographically at 12 and 24 months. Radiographs were assessed for periapical healing based on the periapical index (PAI) scores that were dichotomized as score <3 as healed and ≥3 as not healed. The data were compared using Mann Whitney U test, Kruskal Wallis and post hoc analysis.

Results:

At 24 months, all teeth in Group I and II were healed clinically and radiographically. On inter-group comparison, radiographically, all teeth (n=12) exhibited a PAI score <3 and were categorized as healed (P=1.00).

Conclusion:

The apical extent of MTA plug does not influence the treatment outcome. The clinician can place MTA apical plug either up to or 2 mm short of the radiographic root-end.

A comparison of two pulp revascularization techniques using platelet-rich plasma and whole blood clot

Aim:

The aim of this preliminary study was to compare outcomes of two regenerative endodontic protocols in necrotic teeth with open apices.

Methodology:

Forty teeth with open apices in patients with an age range of 15-54 were randomly distributed in two groups: group 1, with whole blood clot in the canal (n=20) and group 2, whole blood with Platelet rich plasma (PRP) in the canal (n=20). Clinical and radiological follow up assessments were undertaken over a period ranging from 6 months to one year. Radiographic Root Area (RRA) was measured using the freeware ImageJ. Statistical analysis was performed using the independent samples t test and the Chi-squared test, the significance level was set at p=0.05.

Results:

There was no difference in the percentage change in RRA between the PRP group and whole blood-clot + PRP group.

Conclusion:

Whole blood clot and PRP are comparable on the grounds of percentage change in RRA and there is no statistically significant difference between the two in a follow-up period of up to one year.

Long-term follow-up of traumatized immature necrotic permanent teeth treated with regenerative endodontic protocol using platelet-rich fibrin: A prospective case series

The purpose of this prospective case series was to report the long-term clinical and radiographic outcomes of regenerative endodontic procedures (REP) using platelet-rich fibrin (PRF), in traumatized immature permanent teeth with necrotic pulps. Six immature necrotic permanent maxillary central incisors from six patients were treated with REP supplemented with PRF. Patients were recalled at 6, 12, 18, 24, 36, 48, and 60 months. Radiographic changes in the radiographic root area (RRA), apical diameter, root thickness, and root length were quantified. Clinically, tooth survival in terms of tooth retention in the arch and absence of any sign and symptoms of endodontic pathology were noted. All the teeth survived and met the clinical criteria for success throughout the follow-up period. Follow-up radiographs at 5 years revealed complete resolution of the periapical lesions in all patients and the average apical diameter decrease was 30.96%. An average increase of 13.18% for root length, 40.20% for root thickness, and 26.35% for RRA were noted.