Regenerative Endodontic Procedures in Necrotic Mature Teeth with Periapical Radiolucencies: A Preliminary Randomized Clinical Study

IntroductionThis preliminary study compared clinical and radiographic outcomes of regenerative endodontic procedures (REPs) with that of conventional root canal treatment (CRCT) in necrotic mature teeth with periapical radiolucencies.MethodsFifty-six mature necrotic teeth with large periapical radiolucencies were distributed into 2 groups: group 1, REPs and group 2, CRCT (n = 28/group). Clinical and radiographic follow-up assessments were undertaken up to 12 months. Statistical analysis was performed using the independent samples t test and the chi-square test, and the level of significance was set at P = .05.ResultsWith a follow-up rate of about 73.4% of the total patients for 12 months, favorable clinical and radiographic outcomes were found in 92.3% and 80% in REPs and CRCT groups, respectively, and the difference was not statistically significant (P > .05). Half of the teeth treated with REPs responded to the electric pulp test.ConclusionsRegenerative endodontic procedures have the potential to be used as a treatment option for mature teeth with large periapical radiolucencies.     

Regenerative Endodontic Procedures for the Treatment of Necrotic Mature Teeth with Apical Periodontitis: A Systematic Review and Meta-analysis of Randomized Controlled Trials

IntroductionRegenerative endodontic procedures (REPs) are intended to repair and regenerate part of the pulp-dentin complex. The aim of this study was to systematically appraise the existing evidence on the effectiveness of REPs on mature teeth with pulp necrosis and apical periodontitis.MethodsElectronic database and hand searches were performed on 8 databases of published and unpublished literature from inception to January 3, 2021, for the identification of randomized controlled trials (RCTs) or prospective clinical trials. The related key words included “regenerative,” “pulp revascularization,” “revitalization procedure,” and “necrotic mature teeth.” A random effects meta-analysis was conducted assessing success as the main outcome treatment. Risk of bias was assessed through the Cochrane Risk of Bias 2.0 tool, and the quality of the evidence was assessed with the Grading of Recommendations Assessment, Development and Evaluation approach.ResultsOf the 337 initial hits, 4 RCTs were eligible for inclusion, whereas 3 were included in the quantitative synthesis. Overall, there was no difference in the relative risk for a successful/unsuccessful treatment outcome between REPs or conventional treatment (3 studies, relative risk = 1.03; 95% confidence interval, 0.92–1.15; P = .61; heterogeneity I² = 0.0%, P = .53; prediction interval = 0.51–2.09). Risk of bias ranged from low to raising some concerns, whereas the quality of the evidence was graded as moderate.ConclusionsBased on moderate-quality evidence, REPs appear as a viable treatment alternative for mature necrotic teeth with periapical lesions at present. Furthermore, well-designed RCTs might also provide confirmatory evidence in this respect while also framing a backbone for standardization of the therapeutic protocol of REPs.     

Quantitative Assessment of Intracanal Regenerated Tissues after Regenerative Endodontic Procedures in Mature Teeth Using Magnetic Resonance Imaging: A Randomized Controlled Clinical Trial

IntroductionThe present study quantitatively assessed tissue regeneration after regenerative endodontic procedures (REPs) with 2 different apical preparation sizes in mature teeth using magnetic resonance imaging (MRI).MethodsEighteen maxillary anterior mature necrotic teeth with periapical lesions were selected for the study. The teeth were randomly allocated into 2 groups. Canal preparation was performed using Protaper Next files (Dentsply Sirona, York, PA) until size X3 and X5 in the test and control groups, respectively. REPs were performed, and Biodentine (Septodont, Saint-Maur-des-Fossés, France) was used as the cervical plug material. In both groups, MRI was used to measure the signal intensity (SI) of the regenerated tissue at 3, 6, and 12 months at both the middle and the apical thirds of the canal. The SI between the normal contralateral teeth and each successive interval was compared. Clinical examination, sensibility tests, and digital periapical radiographs were also performed at successive time intervals. Statistical analysis was performed using the Student t test and Cochran test. The level of significance was set at P ≤ .05.ResultsAll 18 teeth were symptom free with healing of the periapical lesions. Regarding the SI measurements, there was no statistically significant difference between the SI of the normal contralateral teeth and that of the regenerated tissues in the treated teeth after a 12-month follow-up. In both groups, more than 60% of the cases regained pulp sensibility after 12 months.ConclusionsVital pulplike tissue could be successfully regenerated in mature teeth using REPs, which was not significantly affected by the size of the apical diameter. MRI could successfully assess this tissue in a quantitative, noninvasive manner.     

Histologic Evaluation of Regenerated Tissues in the Pulp Spaces of Teeth with Mature Roots at the Time of the Regenerative Endodontic Procedures

IntroductionRecently, regenerative endodontic procedures (REPs) have been used to treat mature permanent teeth with apical periodontitis. Although animal studies with regard to histopathological findings after REPs exist, there is a paucity of studies on mature human teeth. As yet, the nature of tissues formed in the root canal of such teeth has not been established. This report presents histologic findings with regard to regenerative tissues in the pulp spaces exposed after dental trauma in human mature maxillary incisor teeth successfully treated with REPs.MethodsA 20-year-old girl was referred to our clinic for the treatment of her central incisors (#8 and #9). The incisors had apical periodontitis. REPs were performed on both maxillary central incisors. Three years 5 months after the initial treatment, the teeth had a horizontal crown fracture and needed a fiber post as well as root canal treatment. Mineral trioxide aggregate was carefully removed, and the tissue that had formed in the canal space was processed for routine histologic and immunohistochemical examination.ResultsHistologic findings of the present case showed that the vital tissue formed in the canal space was fibrous connective tissue that contains bonelike tissue, vascular structures, and inflammation. These histologic findings obtained from mature teeth were similar to the findings of previous reports relating to immature teeth.ConclusionsBased on the present case, the vital tissue formed in the canal space is fibrous connective tissue that contains bonelike tissue, vascular structures, and inflammation. These histologic findings with regard to mature teeth were similar to the findings of previous reports relating to immature teeth.     

Combination of Nonsurgical Endodontic and Vital Pulp Therapy for Management of Mature Permanent Mandibular Molar Teeth with Symptomatic Irreversible Pulpitis and Apical Periodontitis

IntroductionThis prospective study evaluated the outcome of a combination of nonsurgical endodontic (NSET) and vital pulp therapy (VPT) for the management of mature permanent mandibular molar teeth with symptomatic irreversible pulpitis (SIP) and apical periodontitis (AP).MethodsInstitutional ethical clearance was obtained. Mandibular molar teeth (N = 60) with a definitive diagnosis of SIP and AP with a radiographic periapical index score (PAI) of ≥3 in either 1 of the roots (mesial or distal) were included. Block randomization was used for allocation. In the NSET group (n = 30), single-visit NSET was performed using a standardized operating protocol. In the NSET-VPT group (n = 30), subsequent to full pulpotomy, at the root orifice where a vital pulp was observed (as determined by the arrest of pulpal bleed upon application of a 2.5% sodium hypochlorite pressure pack), a mineral trioxide aggregate radicular barrier was placed, and it was covered with light-cured resin-modified glass ionomer cement. NSET was performed in the root exhibiting a PAI score ≥3. The tooth was permanently restored. Postoperative pain was assessed at 24, 48, and 72 hours. Teeth were followed up clinically and radiographically at 12 months. The presence/absence of symptoms and the change in PAI scores were noted. The data were statistically analyzed.ResultsThe success rate was 90% in the NSET group and 93.3% in the NSET-VPT group. According to an intergroup comparison between the proportion of teeth healed and nonhealed (radiographic), there was no significant difference (P > .05).ConclusionsThe combination of NSET and VPT is a viable biologically based minimally invasive treatment option for multirooted mandibular teeth with SIP and AP.     

Regenerative Endodontic Therapy in Mature Teeth Using Human-Derived Composite Amnion-Chorion Membrane as a Bioactive Scaffold: A Pilot Animal Investigation

IntroductionHuman-derived composite amnion-chorion membrane (ACM) has been used for various regenerative treatments. The aim of this pilot study was to investigate the effectiveness of the ACM as a scaffold for pulp regeneration in mature canine teeth.MethodsA total of 24 roots from mature premolars in dogs were included for regenerative procedures using blood clots (BC) (group 1, n = 8), collagen membrane (CM) (group 2, n = 8), and ACM (group 3, n = 8). Each tooth was left open through a buccal access to induce root canal infection and inflammation. The root canals were disinfected with 1.5% NaOCl and calcium hydroxide intracanal medicament. After 2 weeks, bleeding was evoked to induce blood clot formation (group 1) or before the placement of the membranes (groups 2 and 3). After 12 weeks, the animals were euthanized for histologic assessment. The histologic data including intracanal fibrous connective tissue, odontoblast-like cell lining, intracanal mineralized tissue, periapical inflammation, and apical closure were qualitatively and quantitively analyzed.ResultsHistologic analysis revealed that intracanal fibrous connective tissue was identified in all groups, but a higher volume of the fibrous tissues was formed in the ACM group. Odontoblast-like cells were only observed in the ACM group. The intracanal mineralized tissue was observed only in the BC and CM groups. The BC group showed more periapical inflammation than the ACM group (P < .05). Apical closure was more often found in the CM group than the BC group (P < .05).ConclusionsMore intracanal fibrous tissue and odontoblast-like cell lining, and less periapical inflammation were observed after regenerative endodontic treatment in mature teeth using the ACM than blood clot alone or blood clot with collagen membrane. The use of the ACM may be useful for a cell-homing–based pulp regeneration in mature teeth.     

Regeneration of Pulp-Dentin Complex in a Tooth with Symptomatic Irreversible Pulpitis and Open Apex Using Regenerative Endodontic Procedures

Regenerative endodontic procedures are undertaken on permanent teeth with necrotic pulps and open apices in an attempt to resolve symptoms, to allow the continued development of the root(s), and to reestablish vitality. The available histologic analysis of these teeth has, in the majority of studies, shown that true regeneration of the pulp-dentin complex is not achieved. A recent investigation using an animal model outlined a procedure wherein pulpal amputation a few millimeters short of the apex followed by evoked bleeding allowed the complete regeneration of the normal pulp-dentin complex in immature vital teeth of ferrets. By implementation of this procedure, we report successful pulp regeneration outcome evidenced by continued root development and a positive response to pulp vitality tests in a maxillary central incisor with an open apex diagnosed with symptomatic irreversible pulpitis.     

Treatment Outcomes of Regenerative Endodontic Procedures in Traumatized Immature Permanent Necrotic Teeth: A Retrospective Study

IntroductionThis retrospective study aimed to evaluate the clinical and radiographic outcomes of regenerative endodontic procedures (REPs) for traumatic immature permanent teeth. Meanwhile, predictors influencing treatment outcomes were also analyzed to provide evidence for the management of immature teeth after different traumatic scenarios.MethodsTraumatized immature permanent teeth diagnosed with pulp necrosis treated by REPs using blood clot or concentrated growth factor scaffolds with at least 6 months of follow-up were included from 2012 to 2021. Treatment outcomes were categorized as a success or failure and survival. Further root development was assessed in terms of the percentage changes in the apical diameter, root length, and radiographic root area. Among different injury types, the clinical and radiographic outcomes of REPs were evaluated by the Fisher exact test and the Kruskal-Wallis test, respectively. Survival analysis and Cox regression analysis were performed to identify significant predictors affecting outcomes.ResultsSixty-two teeth with a mean of 22.3 months of follow-up satisfied the criteria, and 80.6% of the teeth had a successful outcome. A significant change was observed in a decrease of the apical diameter (69.3%) and an increase of the radiographic root area (22.6%) after REPs. Among different injury types, the success rates of REPs were as follows: fracture, 84.6%; luxation, 83.3%; combined injuries, 78.6%; and avulsion, 33.3% (P > .05). Fractured teeth had a significantly greater decrease of the apical diameter than combined injuries (P < .05). Avulsion was more prone to developing root resorption than fracture (P < .05). Scaffold was a significant predictor for success; a blood clot had a significantly reduced risk for failure than concentrated growth factor (hazard ratio = 16; 95% confidence interval, 2.1–125.2; P < .001).ConclusionsREPs provided satisfactory outcomes in traumatized immature permanent necrotic teeth. However, severe injuries, especially avulsion, should be determined carefully to perform REPs when resorption is expected. Scaffold selection may be an important consideration.     

Influence of Apical Diameter on the Outcome of Regenerative Endodontic Treatment in Teeth with Pulp Necrosis: A Review

Introduction

The aim of this review was to evaluate whether the apical diameter of teeth with necrotic pulp affects the outcomes of regenerative endodontic treatment and to determine the minimal apical size needed to obtain proper pulp revascularization.

Quantitative Assessment of Root Development after Regenerative Endodontic Therapy: A Systematic Review and Meta-Analysis

IntroductionThe purposes of this review were to appraise the level of evidence of the existing regenerative endodontic therapy (RET) publications, perform a meta-analysis on the survival and healing rates of necrotic immature permanent teeth treated with RET, and run a meta-analysis on the quantitative assessment of the root development of those teeth.MethodsElectronic searches were performed in Web of Science, PubMed, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Cochrane Library databases. Two authors independently screened the titles and abstracts for eligibility. The analyses were performed on the clinical outcomes (ie, survival, healing, and root development) of the procedure.ResultsEleven articles were included in the qualitative and quantitative syntheses. Three studies were randomized controlled trials, 6 were prospective cohort studies, and 2 were retrospective cohort studies. The pooled survival and healing rates were 97.3% and 93.0%, respectively. The pooled rates of root lengthening, root thickening, and apical closure were 77.3%, 90.6%, and 79.1%, respectively. However, if 20% radiographic changes were used as a cutoff point, there were only 16.1% root lengthening and 39.8% root thickening.ConclusionsWithin the limitations of the present study, it can be concluded that RET yielded high survival and healing rates with a good root development rate. However, clinical meaningful root development after RET was unpredictable.     

Regenerative Endodontic Treatment or Mineral Trioxide Aggregate Apical Plug in Teeth with Necrotic Pulps and Open Apices: A Systematic Review and Meta-analysis

Introduction

A mineral trioxide aggregate (MTA) apical plug (MAP) and regenerative endodontic treatment (RET) have shown acceptable clinical outcomes. However, comparative studies are scarce. The aims of this study were to examine the level of evidence for both treatments, conduct a systematic review of the literature on MAP and RET, and run a meta-analysis on the survival and success rates of teeth treated with these procedures.

Regenerative Endodontic Treatment with Orthodontic Treatment in a Tooth with Dens Evaginatus: A Case Report with a 4-year Follow-up

Dens evaginatus is a developmental tooth anomaly in which an extra cusp or tubercle protrudes on the occlusal surface of the tooth along with some pulpal tissue. Because of the fragile nature of the protrusion, these teeth are often at risk of pulpal exposure. When this occurs in an immature tooth, regenerative endodontic treatment may be a good treatment approach to promote root formation. There is limited literature that documents the occurrence of orthodontic treatment in teeth that have undergone regenerative endodontic therapy using triple antibiotic paste. Here we present a case of an immature premolar tooth with dens evaginatus that was diagnosed with pulp necrosis and chronic apical abscess. The tooth was treated with regenerative endodontic treatment; after which, the patient received orthodontic treatment with fixed appliances for 2 years. The tooth responded favorably to the regenerative endodontic treatment and orthodontic tooth movement. Clinically and radiographically, all the follow-up examinations revealed an asymptomatic tooth with evidence of periapical healing with stunted root development. The tooth remained asymptomatic even after 4 years. The regenerative endodontic procedure (REP) was successful in treating an immature permanent premolar with pulp necrosis and apical periodontitis with dens evaginatus. In this case, the tooth treated with an REP responded to orthodontic treatment similar to the nonendodontically treated teeth. Further studies are recommended to clarify the precise effects of orthodontic treatment on teeth treated with an REP.     

Long-term Outcomes of Endodontic Treatment Performed with Resilon/Epiphany

Introduction

Resilon (Resilon Research LLC, Madison, CT) with Epiphany Sealer (Pentron Clinical Technologies, Wallingford, CT) was introduced into the market in 2004 as a new method of root canal obturation. This material as well as the traditionally used gutta-percha with AH Plus sealer (Dentsply Maillefer, Tulsa, OK) were in use over a 9-year span in the University of North Carolina endodontic clinics. Although Resilon was initially thought to create a “monoblock” seal between the material and the canal, in vitro studies later suggested this concept not to be true. The long-term outcome of Resilon using a validated radiographic index and a systematic approach has not been reported. The purpose of this retrospective cohort study was to radiographically evaluate the outcome of Resilon/Epiphany-treated root canals compared with traditional gutta-percha/AH Plus.

Vital pulp therapy of mature permanent teeth with irreversible pulpitis from the perspective of pulp biology

The American Association of Endodontists (AAE) Consensus Conference Recommended Diagnostic Terminology states that mature permanent teeth clinically diagnosed with irreversible pulpitis are treated with pulpectomy and root canal filling because inflamed vital pulp is not capable of healing. Histological studies have demonstrated that clinically diagnosed irreversible pulpitis does not involve the entire pulp. A recent International Endodontic Journal Editorial suggested clinical diagnosis of pulp disease should be reassessed because of the poor correlation between clinical symptoms and pulp sensibility testing and the actual histological status of the pulp. This review identified studies in a PubMed search that provide evidence for vital pulp therapy (VPT) of mature permanent teeth with irreversible pulpitis is predictable if correctly diagnosed and properly treated. A narrative review was undertaken to outline the correlation between the clinical symptoms/signs and pulp sensibility testing and the histological findings of the pulp. Treatment procedures for permanent teeth are outlined.     

Clinical and Molecular Microbiological Evaluation of Regenerative Endodontic Procedures in Immature Permanent Teeth

IntroductionThis study evaluated the bacterial levels after regenerative endodontic procedures and their correlation with the treatment outcome using molecular microbiology methods.MethodsRoot canal samples of 15 necrotic immature teeth were analyzed by quantitative polymerase chain reaction. Bacteria were counted before treatment (S1), after irrigation with 6% sodium hypochlorite (S2), and after intracanal dressing (S3) using either triple antibiotic paste (n = 7) or calcium hydroxide with chlorhexidine (n = 8). The Wilcoxon test for related samples and the Mann-Whitney test were used for statistical analysis (P < .05). After a follow-up period of 12–48 months, clinical and radiographic findings were correlated with microbiological data using a linear regression model (P < .05).ResultsAll S1 and S2 samples were positive for bacteria, but the number of positive S3 samples decreased to 53.3% (P = .001). Overall, there was a significant reduction of bacterial levels after each treatment step (S1–S2, P = .001; S2–S3, P = .02). In the triple antibiotic paste and chlorhexidine groups, 57.1% and 50% of S3 samples were positive with median numbers of 6.97 × 10³ and 3.59 × 10⁴ bacterial cells, respectively. No significant differences were found between the groups. Periapical healing occurred in all cases despite the presence of low levels of residual bacteria. However, the latter had a negative impact on the thickness of dentinal walls (R² = 0.0043).ConclusionsAlthough the bacterial levels were drastically reduced after the regenerative endodontic procedures, the residual bacteria influenced the thickness of the dentinal walls.     

Clinical,Radiographic, and Histologic Outcome of Regenerative Endodontic Treatment in Human Teeth Using a Novel Collagen-hydroxyapatite Scaffold

Introduction

Histologic examination of teeth after regenerative endodontic treatment (RET) shows that the type, quality, and quantity of tissues formed in the root canal space are not predictable. The aim of this study was to examine clinically, radiographically, and histologically the outcome of RET in immature noninfected human teeth using SynOss Putty (Collagen Matrix Inc, Oakland, NJ) as a scaffold.

Histobacteriologic Conditions of the Apical Root Canal System and Periapical Tissues in Teeth Associated with Sinus Tracts

Introduction

This histobacteriologic study described the pattern of intraradicular and extraradicular infections in teeth with sinus tracts and chronic apical abscesses.

Outcome of Regenerative Endodontic Procedures in Nonvital Immature Permanent Teeth Using 2 Intracanal Medications: A Prospective Randomized Clinical Study

IntroductionThis randomized clinical trial aimed to assess and compare the long-term clinical and radiographic outcomes of regenerative endodontic procedures (REPs) in treating nonvital immature permanent teeth using 2 intracanal medicaments.MethodsForty-five patients yielding a total of 50 anterior and posterior nonvital immature teeth were randomly divided into 2 groups. REPs using either nonsetting calcium hydroxide (Ca[OH]₂) (n = 25) or modified triple antibiotic paste (TAP) (n = 25) as intracanal medicaments were performed. NeoMTA Plus (Avalon Biomed Inc) was applied for coronal sealing. Cases were followed up clinically and radiographically for 36 months. The 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.ResultsAt the 36-month follow-up, the 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 the nonsetting Ca(OH)₂ and modified TAP groups (P > .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 groups (P ≥ .39). Intracanal calcifications were detected in 60% of cases with no significant difference between groups (P = .77).ConclusionsREPs, using either nonsetting Ca(OH)₂ or modified TAP as the intracanal medicament, exhibited high success and survival rates over a follow-up period of 36 months with equally favorable clinical and radiographic outcome data.     

Histologic Characterization of Engineered Tissues in the Canal Space of Closed-apex Teeth with Apical Periodontitis

Introduction

The aim of this study was to investigate the capacity of endodontic regenerative procedures combining an induced blood clot, platelet-rich plasma (PRP), and bone marrow aspirate (BMA) to regenerate dental pulp in canine closed-apex necrotic teeth.

Methods

Apical periodontitis was induced in 20 upper and lower premolars of 2 dogs. After biomechanical preparation, enlargement to a #60 file, and disinfection with a triantibiotic paste for 28 days, the roots were randomly assigned to 4 treatment groups: blood clot (BC), BC + PRP gel, BC + BMA gel, and BC + BMA/PRP gel. Negative controls were also included. After a 3-month follow-up period, the animals were killed.

Results

Histologic analysis showed the presence of newly formed vital tissues (connective, cement-like, and bone-like tissue) in 23 of the 32 treated roots (71.87%). There was no statistically significant difference between the treatment groups.

Conclusions

New vital tissues were formed and characterized as connective, cementum-like, or bone-like, but not as pulp-like tissue; PRP and/or BMA did not improve the tissue ingrowth.