Regenerative Endodontic Therapy: A Data Analysis of Clinical Protocols

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.

GelMA-based hydrogel biomaterial scaffold: A versatile platform for regenerative endodontics

Endodontic therapy, while generally successful, is primarily limited to mature teeth, hence the pressing need to explore regenerative approaches. Gelatin methacryloyl (GelMA) hydrogels have emerged as pivotal biomaterials, promising a bright future for dental pulp regeneration. Despite advancements in tissue engineering and biomaterials, achieving true pulp tissue regeneration remains a formidable task. GelMA stands out for its injectability, rapid gelation, and excellent biocompatibility, serving as the cornerstone of scaffold materials. In the pursuit of dental pulp regeneration, GelMA holds significant potential, facilitating the delivery of stem cells, growth factors, and other vital substances crucial for tissue repair. Presently, in the field of dental pulp regeneration, researchers have been diligently utilizing GelMA hydrogels as engineering scaffolds to transport various effective substances to promote pulp regeneration. However, existing research is relatively scattered and lacks comprehensive reviews and summaries. Therefore, the primary objective of this article is to elucidate the application of GelMA hydrogels as regenerative scaffolds in this field, thereby providing clear direction for future researchers. Additionally, this article provides a comprehensive discussion on the synthesis, characterization, and application of GelMA hydrogels in root canal therapy regeneration. Furthermore, it offers new application strategies and profound insights into future challenges, such as optimizing GelMA formulations to mimic the complex microenvironment of pulp tissue and enhancing its integration with host tissues.

Does the use of different scaffolds have an impact on the therapeutic efficacy of regenerative endodontic procedures? A systematic evaluation and meta-analysis

BACKGROUND

In the regenerative endodontic procedures, scaffolds could influence the prognosis of affected teeth. Currently, there is controversy regarding the postoperative evaluation of various scaffolds for pulp regeneration. The objective of this study was to access whether other scaffolds, used alone or in combination with blood clot (BC), are more effective than BC in regenerative endodontic procedures.

METHODS

We systematically search the PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and Google Scholar databases. Randomized controlled trials examining the use of BC and other scaffold materials in the regenerative endodontic procedures were included. A random effects model was used for the meta-analysis. The GRADE method was used to determine the quality of the evidence.

RESULTS

We screened 168 RCTs related to young permanent tooth pulp necrosis through electronic and manual retrieval. A total of 28 RCTs were related to regenerative endodontic procedures. Ultimately, 12 articles met the inclusion criteria and were included in the relevant meta-analysis. Only 2 studies were assessed to have a low risk of bias. High quality evidence indicated that there was no statistically significant difference in the success rate between the two groups (RR=0.99, 95% CI=0.96 to 1.03; 434 participants, 12 studies); low-quality evidence indicated that there was no statistically significant difference in the increase in root length or root canal wall thickness between the two groups. Medium quality evidence indicated that there was no statistically significant difference in pulp vitality testing between the two groups.

CONCLUSIONS

For clinical regenerative endodontic procedures, the most commonly used scaffolds include BC, PRP, and PRF. All the different scaffolds had fairly high clinical success rates, and the difference was not significant. For regenerative endodontic procedures involving young permanent teeth with pulp necrosis, clinical practitioners could choose a reasonable scaffold considering the conditions of the equipment and patients.

Citric Acid Conditioning as an Alternative to EDTA for Growth Factors Release and Stem Cell Response in Regenerative Endodontics: A Systematic Review of In Vitro Studies

INTRODUCTION

Citric acid (CA) conditioning may be a promising alternative to ethylenediaminetetraacetic acid (EDTA) in regenerative endodontic procedures, as reported to improve growth factors' release from dentin. This review systematically investigated the effect of CA conditioning on the growth factors release from dentin and cell behavior compared to EDTA conditioning.

METHODS

Searches were conducted (PubMed/MEDLINE, Scopus, Web of Science, Embase, SciELO, Cochrane Library, and grey literature) until May-2023. Only in vitro studies that evaluated the effects of CA on growth factors' release from dentin and cell behavior outcomes compared to EDTA were included. The studies were critically appraised using a modified Joanna Briggs Institute's checklist. Meta-analysis was unfeasible.

RESULTS

Out of the 335 articles screened, nine were included. Among these, three studies used dentin discs/roots from permanent human teeth; the rest combined them with stem cells. 10% CA for 5 or 10 minute was the most used protocol. Meanwhile, EDTA concentrations ranged from 10% to 17%. In eight studies examining the release of growth factors, five reported a significant release of transforming growth factor-β after dentin conditioning with 10% CA compared to 17% EDTA. Regarding cell behavior (6 studies), three studies assessed cell viability. The findings revealed that 10% CA conditioning showed cell viability similar to those of 17% EDTA. Additionally, in two out of three studies, it was observed that 10% CA conditioning did not affect cell morphology. The studies had a low risk of bias.

CONCLUSIONS

The use of 10% CA to condition dentin for 5-10 minutes resulted in a notable transforming growth factor -β1 release, but its cell responses were similar to those of EDTA.

Current Trends in Regenerative Endodontics: A Web-based Survey

INTRODUCTION

The aim of this study was to ascertain the current trends in regenerative endodontic procedures (REPs) among clinicians, including case selection criteria and clinical protocols.

METHODS

An online questionnaire consisting of provider demographics, case selection criteria for REPs, and clinical protocols was made available to members of the American Association of Endodontists and members of the Endolit website. Data were analyzed using the Fisher exact test.

RESULTS

Two hundred seventy-two responses were analyzed (64.6% were men and 34.7% were women). Of those, 44.5% of respondents practiced in the United States, and 55.5% practiced outside of the Unites States. Most respondents (85.4%) reported performing REPs in their practice, and 92.2% were using sodium hypochlorite as one of their disinfecting irrigants. Calcium hydroxide was the most commonly used intracanal medicament (68.4%), and the majority of respondents use a blood clot alone as the scaffold (73.5%). Most (93%) of the providers reported using a bioceramic material for coronal capping. Practitioners outside the United States were found to be more likely to use adjunctive irrigation activation (P = .003). Younger practitioners preferred REPs over apexification (P = .01). Practitioners outside the United States were more likely to perform an REP in 1 visit (P = .006). Men were found to be more likely to always instrument the canal walls (P = .031). Women were found to be more likely to use manual irrigant activation, whereas men were more likely to use sonic activation (P = .043).

CONCLUSIONS

There is significant heterogeneity within REPs regarding case selection and clinical protocol. Notable differences were observed from the reported findings of REPs from 5 years ago.

Unlocking the Potential of Cellular Guidance in Endodontics: Advancing the Process of Pulp Regeneration and Beyond

Regenerative endodontics represents a paradigm shift in dental therapy, with the potential to not only restore damaged dental tissues but also to preserve the vitality of teeth. At the heart of this innovative approach is cell homing, a technique that harnesses the body's own healing mechanisms by recruiting endogenous stem cells to the site of dental injury for effective tissue regeneration. This review delves into the intricate processes of cell homing in the context of regenerative endodontics, particularly focusing on its application in immature teeth with open apices. It examines the role of bioactive molecules, scaffolds, and growth factors in orchestrating cell migration and differentiation within the root canal space. In addition, the review addresses the current limitations in clinical practice, such as the challenges in completely regenerating the pulp-dentin complex and the unpredictability in long-term outcomes. It also explores future possibilities, including the potential for more refined and effective regenerative strategies. By providing a comprehensive overview of the current state of cell homing in regenerative endodontics, this article aims to contribute to the ongoing development of advanced therapeutic techniques that could revolutionize endodontic treatment and improve patient care.

Success and Complication Rates of Revascularization Procedures for Immature Necrotic Teeth: A Systematic Review

Frequently, adolescents exhibit instances of immature necrotic teeth, which are identifiable by their slender root walls and unclosed root tips. The lack of a natural narrowing near the root's end creates difficulty when using standard endodontic procedures, making the effective sealing of the immature root canal difficult or impractical. Revascularization therapy surfaces as a prospective strategy for addressing the management of undeveloped, non-vital, immature, necrotic teeth. Notwithstanding this, apexification continues to hold prominence in the preferences of clinicians owing to its perceived predictability in treatment outcomes. A systematic investigation was conducted involving various search engines and databases, covering the period from 2001 to 2023. The main aim of this investigation was to find randomized clinical trials that compared the efficacy of revascularization therapy to apexification for treating immature necrotic teeth. The evaluation included a thorough examination of both clinical and radiographic outcomes assessing the success rates and complications. Out of the 850 identified articles, 15 studies were chosen for comprehensive analysis. Notable dissimilarities were not identified between the revascularization therapy and apexification groups concerning parameters such as rates of periapical healing, overall effectiveness/invalidation, and apical closure. However, concentrating on measurable factors, it became clear that the revascularization treatment group displayed a notable rise in root length compared to the apexification group. Both revascularization endodontic therapy and apexification demonstrated effectiveness in addressing periapical periodontitis healing and open apex closure. Pulp revascularization stood out for its notable efficacy in enhancing root elongation and thickening, all while having a reduced likelihood of treatment being deemed ineffective overall.

Attitude and practice of regenerative endodontic procedures among endodontists and paediatric dentists: A multinational survey from 13 countries

BACKGROUND

Regenerative endodontics (RET) refers to biologically based procedures that aim to restore damaged tooth structures and reinstate the pulp-dentine complex to its normal physiological state.

AIM

The purpose of this study was to examine the attitudes and practices of endodontists and paediatric dentists regarding RET.

DESIGN

A survey was conducted among endodontists and paediatric dentists from 13 countries. A number of factors were evaluated, including frequency of RET application, followed guidelines, disinfection techniques, intracanal medication type, scaffold type, preferred coronal seal material, and follow-up period.

RESULTS

Among the 1394 respondents, 853 (61.2%) and 541 (38.8%) were endodontists and paediatric dentists, respectively. Almost half (43%) of participants have not performed RET yet. The American Association of Endodontics guideline (47.3%) was selected as the primary source for the clinical protocol. The most frequently selected irrigant solution was 1.5%-3% NaOCl at the first (26.1%) and second (13.6%) sessions. A blood clot (68.7%) and MTA (61.9%) were the most frequently selected scaffold type and coronal barrier. Most participants preferred a 6-month follow-up period.

CONCLUSION

According to this survey, deviations exist from current RET guidelines regarding all aspects evaluated. Standardizing clinical protocols and adhering to available guidelines would help to ensure more predictable outcomes.

Efficacy of disinfection procedures performed prior to regenerative endodontic therapy: An integrative review

The aim of this integrative review was to identify whether the disinfection procedures performed prior to regenerative endodontic treatment were effective on biofilm removal from the root canals. The research was based on PubMed, Latin American and Caribbean Health Sciences Literature (Lilacs) and Scientific Electronic Library Online (SciELO) databases. Four articles were selected; one of the studies was in vivo and the others ex vivo. Different disinfection procedures were studied, characterised mainly by the use of intracanal medication, highlighting the double antibiotic paste, triple antibiotic paste and calcium hydroxide paste. Disinfection ability was evaluated against Enterococcus faecalis and multispecies biofilms by using the fluorescence technique and colony forming unit counting, for 7 to 21 days. Double antibiotic paste and triple antibiotic paste demonstrated excellent antibiofilm activity, unlike CH paste that showed limited disinfection, even when associated with different antimicrobial agents. Triple antibiotic paste was the most effective medication against biofilm.

Chitosan (CS)/Hydroxyapatite (HA)/Tricalcium Phosphate (β-TCP)-Based Composites as a Potential Material for Pulp Tissue Regeneration

This research focused on developing new materials for endodontic treatments to restore tissues affected by infectious or inflammatory processes. Three materials were studied, namely tricalcium phosphate β-hydroxyapatite (β-TCP), commercial and natural hydroxyapatite (HA), and chitosan (CS), in different proportions. The chemical characterization using infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the composition of the composite. Scanning electron microscopy (SEM) demonstrated that the design and origin of the HA, whether natural or commercial, did not affect the morphology of the composites. In vitro studies using Artemia salina (A. salina) indicated that all three experimental materials were biocompatible after 24 h, with no significant differences in mortality rate observed among the groups. The subdermal implantation of the materials in block form exhibited biocompatibility and biodegradability after 30 and 60 days, with the larger particles undergoing fragmentation and connective tissue formation consisting of collagen type III fibers, blood vessels, and inflammatory cells. The implanted material continued to undergo resorption during this process. The results obtained in this research contribute to developing endodontic technologies for tissue recovery and regeneration.

Evaluation of postoperative pain and healing following regenerative endodontics using platelet-rich plasma versus conventional endodontic treatment in necrotic mature mandibular molars with chronic periapical periodontitis. A randomized clinical trial

AIM

To evaluate the post-operative pain and the healing of necrotic mature permanent mandibular molar teeth with peri-apical periodontitis after conventional endodontic treatment versus after platelet-rich plasma (PRP) revascularization.

METHODOLOGY

The protocol of this randomized clinical trial was registered at www.

CLINICALTRIALS

gov with identification number NCT03350841. Twenty-eight patients were included in the study after confirming the diagnosis clinically and radiographically. In the first visit, mandibular molar teeth of both groups were mechanically prepared. Double antibiotic paste was prepared and injected then the cavity that was sealed with glass ionomer. At the second visit, the patients were randomized either to control group where standard endodontic treatment was completed by lateral condensation technique or assigned to intervention group where PRP revascularization technique. The degree of spontaneous pain was assessed using numerical rating scale (NRS) pre-operatively, then post-operatively after 6, 12 h and daily for 5 days. Patients were given a placebo to be administrated in case of pain. An analgesic (ibuprofen 400mg) was prescribed in case of persistent pain. Clinical and radiographic healing was assessed after 6 and 12 months. All demographic, baseline and outcome data were collected and statistically analysed.

RESULTS

Regarding the post revascularization/obturation pain, there was no statistically significant difference between severity of pain in the two groups at all time intervals except after 12 h, revascularization group showed statistically significantly higher prevalence of no pain than endodontic treatment group. Regarding the healing; the periapical lesions decrease in size significantly from the pre-operative lesion size in both groups without significant difference between the both groups.

CONCLUSION

Within the limitation of this study, PRP revascularization could be an alternative treatment to root canal treatment but further randomized clinical trials with standardized techniques and long follow up periods are recommended for more reliable results.

Microstructure and color stability of calcium silicate-based dental materials exposed to blood or platelet-rich fibrin

OBJECTIVES

To investigate the effects of blood and platelet-rich fibrin (PRF), commonly used scaffolds in regenerative endodontic treatment (RET), on the hydration, microstructure, and color stability of three hydraulic calcium silicate cements (HCSCs), OrthoMTA, RetroMTA, and TotalFill-BC-RRM.

MATERIALS AND METHODS

The HCSCs were prepared and placed into polyethylene molds and transferred to Eppendorf tubes containing PRF, blood, or PBS and then incubated for 1 week or 1 month. The microstructure and hydration of the cements were studied by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The chromatic alteration of materials was also measured using a spectrophotometer. The data for color stability were analyzed using 2-way analysis of variance and Tukey post hoc tests.

RESULTS

There was no significant difference between the color stability of cements exposed to PBS (p > 0.05). The chromatic alteration of cements exposed to blood was significantly greater than those exposed to PRF and PBS (p < 0.001). In the presence of blood and PRF, the color change of OrthoMTA was significantly greater than that of RetroMTA and TotalFill (p < 0.05), with no significant difference between RetroMTA and TotalFill (p > 0.05). XRD analysis of all cements revealed a calcium hydroxide peak after 1-week and 1-month exposure to the media; however, OrthoMTA and TotalFill exposed to blood and PRF for 1 month showed weaker calcium hydroxide peaks. SEM images revealed cements exposed to PBS had a different surface microstructure compared to those exposed to blood and PRF. Furthermore, the surface microstructure of HCSCs was influenced by the type of cement radiopacifier (bismuth oxide or zirconium oxide). EDS analysis of the elemental composition in all groups displayed peaks of Ca, O, C, Si, P, and Al.

CONCLUSIONS

Color stability, hydration behavior, and microstructure of HCSCs were affected by exposure to PRF and blood and the type of cement radiopacifier.

CLINICAL RELEVANCE

As some important physicochemical properties of HCSCs could be influenced by the environmental conditions and the type of radiopacifier, alternatives to blood clot and HCSCs containing substitutes for bismuth oxide might be more suitable in RETs.

Regenerative Endodontics-Reviving the Pulp the Natural Way: A Case Report

Regenerative endodontic therapy (RET) offers a novel treatment option for developing teeth with pulp necrosis. In the current instance, RET was used to treat an immature mandibular permanent first molar that had been identified with irreversible pulpitis. The root canals were treated with triple antibiotic paste (TAP) and 1.5% sodium hypochlorite (NaOCl) irrigation. TAP was removed, and 17% ethylenediaminetetraacetic acid (EDTA) was used to treat the root canals during the second visit. As a scaffold, Platelet-rich fibrin (PRF) was applied. Mineral trioxide aggregate (MTA) was applied over PRF, and composite resin was used to repair the teeth. Radiographs taken from the posterior were utilized to assess the healing. The teeth displayed no signs of pain and healing after the six-month follow-up periods, and pulp sensibility tests using a cold and electric pulp tester produced no results. Conservative treatment options should be considered to save immature permanent teeth and assist in the regeneration of the root apex.

Enhancement of acellular biomineralization, dental pulp stem cell migration, and differentiation by hybrid fibrin gelatin scaffolds

OBJECTIVE

The current in vitro study aims to evaluate cross-linked hydrogels with and without the addition of fibrin that could potentially be used in endodontic regeneration as a scaffold material.

METHODS

Synthesis of gelatin/fibrin scaffold, and performing nanoscale characterization using cryo-electron microscopy, dynamic rheology, and XRF for structure property relations; plating dental pulp stem cells and determining mineralization, migration, and differentiation using rt-PCR, XRF, and Raman spectroscopy.

RESULTS

Cryo electron imaging shows gelatin and fibrin, when gelled separately to form classical rectangular cross-linked networks, where the modulus scales inversely with the cube root of the mesh size. When gelled together, a network with a fundamentally different structure is formed, which has higher ductility and when placed as a scaffold in osteogenic media, produces twice the mineral content. Immunofluorescence, RT-PCR and Rahman Spectroscopy indicate that the hybrid gel enhances cell migration, induces odontogenic differentiation of dental pulp stem cells, and promotes formation of dentin.

SIGNIFICANCE

The mechanical properties of the hybrid gel scaffold enhance in-migration of stem cells and subsequent differentiation, which are critical for regenerative procedures. Under acellular conditions, placement of the hybrid gel enhances biomineralization, which would strengthen the root if used as a scaffold for endodontic regeneration. Our in vitro findings are consistent with previous in vivo studies which show improved mineralization when bleeding is induced into the canal, given that fibrin is a primary component in blood clotting. Therefore, insertion of the hybrid gelatin-fibrin scaffold could enable more reproducible and consistent outcomes if used for regenerative endodontic treatment (RET).

Effects of ethylenediaminetetraacetic acid on stem cells from the apical papilla: In vitro study

Background/purpose

Ethylenediaminetetraacetic acid (EDTA) is used as an irrigant in regenerative endodontic treatment. The present study aimed to investigate the effects of EDTA on stem cells from apical papilla (SCAPs) in vitro.

Materials and methods

Human SCAPs were isolated and characterised. The cells were treated with media supplemented with EDTA at concentrations ranging from 1.25% to 17%. Cell proliferation and apoptosis were examined using MTT assay and annexin V/propidium iodide staining. Cell migration was determined by a scratch assay. Gene expression was evaluated using a real-time polymerase chain reaction. Mineral deposition, a hallmark of osteogenesis in vitro, was determined using alizarin red s staining.

Results

Overall, SCAPs exhibited mesenchymal stem cell characteristics. EDTA treatment at 2.50% and 1.25% did not significantly exhibit cytotoxicity and alter cell morphology. However, EDTA attenuated cell proliferation and reduced MKI67 mRNA expression in SCAPs. Further, EDTA significantly induced early cell apoptosis at 48 h. Cell migration was delayed with EDTA treatment. After maintaining SCAPs in an osteogenic induction medium, EDTA diminished mineral deposition by SCAPs on day 14.

Conclusion

EDTA treatment exhibits adverse effects on SCAPs in vitro. Hence, EDTA exposure to periapical tissues should be avoided to minimise the negative impacts on SCAPs cells in regenerative processes.

Comparative evaluation of antibacterial efficacy of nonsteroidal anti-inflammatory medications and proton-pump inhibitor against Enterococcus faecalis: An in vitro study

Aim

The present in vitro experimental study was undertaken to evaluate and compare the antimicrobial activity of triple antibiotic paste (TAP), diclofenac, and proton-pump inhibitor (PPI) against the microorganism Enterococcus faecalis.

Materials and Methods

Three medicaments were selected for the study, TAP, diclofenac, and PPI. The experimental groups for the test were as follows: Part 1 - Group 1: TAP, Group 2: diclofenac, and Group 3: PPI; Part 2 - Group 1: TAP + PPI and Group 2: diclofenac + PPI. An agar well diffusion test was used to determine the efficacy of the experimental medicaments against E. faecalis (ATCC 29212). The diameter of inhibition zones was measured in millimeters using an inhibition zone measuring scale and the results were recorded.

Statistical Analysis

The statistical analysis was done using an analysis of variance and an unpaired t-test. P value was set at < 0.05.

Results

There was a significant difference in the diameter of growth inhibition zones, with the greatest diameter noted for TAP + PPI followed by diclofenac sodium (DS) + PPI, TAP, DS, and PPI.

Conclusions

The antimicrobial effectiveness of TAP + PPI was found to be superior to all other medicaments (DS + PPI, TAP, DS, and PPI).

Are platelet concentrate scaffolds superior to traditional blood clot scaffolds in regeneration therapy of necrotic immature permanent teeth? A systematic review and meta-analysis

BACKGROUND

The effectiveness of platelet concentrates in promoting root development of necrotic immature permanent teeth is unclear. The present study evaluated whether the platelet concentrate protocol was superior to the traditional blood clot protocol in regeneration therapy.

METHODS

We searched Electronic databases, such as PubMed, Cochrane Library, ClinicalTrials and EMBASE. Randomized controlled trial studies, cohort studies, case-control studies and cross-sectional studies were included, in which platelet-rich concentrates were tested for periapical healing and root development, with the blood clot treatment protocol as the control group. Clinical and radiographic outcomes were considered. Selected articles were assessed for risk of bias. Pooled risk ratios (risk ratio, RR) were calculated for clinical success, responses to cold and electric pulp tests, periapical lesions, apex closure, root lengthening, and thickening of the dentin walls. Subgroup meta-analysis were conducted according to the type of platelet concentrate used.

RESULTS

Of the 1272 screened studies, 13 randomized controlled studies, 2 case-control studies and 1 cohort study were selected, in which 465 immature necrotic permanent teeth, particularly incisors and premolars, were treated. Of these 465 teeth, 457 (98.2%) in both the control and experimental groups remained clinically asymptomatic for the entire study duration, whereas eight (1.8%) showed signs and symptoms of failure, including spontaneous pain, sensitivity to percussion or reinfection. Compared with control teeth, teeth treated with PRP achieved better apical healing than BC group (RR 1.13, 95% CI 1.01-1.26, P = 0.03), and teeth treated with platelet concentrates showed improved apical closure (RR 1.04, 95% CI 0.86-1.25, P = 0.69), root lengthening (RR 1.01, 95% CI 0.74-1.39, P = 0.93), and thickening of the dentin walls (RR 1.35, 95% CI 0.95-1.93, P = 0.09), although these differences were not statistically significant.

CONCLUSIONS

Platelet concentrates can be used as successful scaffolds for regenerative endodontic treatment of necrotic immature permanent teeth, and PRP as a scaffold may achieve better periapical healing of teeth with periapical inflammation, although they did not differ significantly from conventional blood clot scaffolds in development of the root.

Expert consensus on regenerative endodontic procedures

Regenerative endodontic procedures (REPs) is a biologic-based treatment modality for immature permanent teeth diagnosed with pulp necrosis. The ultimate objective of REPs is to regenerate the pulp-dentin complex, extend the tooth longevity and restore the normal function. Scientific evidence has demonstrated the efficacy of REPs in promotion of root development through case reports, case series, cohort studies, and randomized controlled studies. However, variations in clinical protocols for REPs exist due to the empirical nature of the original protocols and rapid advancements in the research field of regenerative endodontics. The heterogeneity in protocols may cause confusion among dental practitioners, thus guidelines and considerations of REPs should be explicated. This expert consensus mainly discusses the biological foundation, the available clinical protocols and current status of REPs in treating immature teeth with pulp necrosis, as well as the main complications of this treatment, aiming at refining the clinical management of REPs in accordance with the progress of basic researches and clinical studies, suggesting REPs may become a more consistently evidence-based option in dental treatment.

Use of scaffolds and regenerative materials for the treatment of immature necrotic permanent teeth with periapical lesion: Umbrella review

BACKGROUND

Current treatment of immature necrotic permanent teeth with a periapical lesion is regenerative endodontics, which is based on tissue engineering under the triade of stem cells, scaffolds and bioactive molecules.

OBJECTIVES

This Umbrella Review was aimed to evaluate the success of scaffold and regenerative materials used for the treatment of these teeth, in terms of apical closure, tooth length increase, widening of root canal walls, tissue vitality and periapical lesion repair.

METHODS

An extensive literature research was carried out in the Medline, ISI Web of Science, and Scopus databases for relevant systematic reviews matching the keyword search strategy. Based on inclusion and exclusion criteria, reviewers independently rated the quality of each study to determine their level of evidence. Methodological quality assessment of each article was obtained using A Measurement Tool to Assess Systematic Reviews (AMSTAR)-2 tool, and risk of bias was assessed with the Risk of Bias in Systematic Reviews (ROBIS) tool.

RESULTS

After removing duplicates, 155 articles were found; from which 133 were excluded for being non-relevant and 15 other due to exclusion criteria. One more was discarded after methodological quality evaluation, for a total of six articles remaining. The most common scaffold used was the blood clot, others used were poly lactic-co-glycolic acid and platelet-rich fibrin matrix. The most common regeneration material used was Mineral Trioxide Aggregate (MTA), followed by Biodentine. An increase in tooth length and widening of root canal walls were reported in all selected studies with different proportions, as well as periapical lesion repair. ROBIS analysis showed that only one article had low bias, two were classified as unclear bias, while the remaining three had high risk of bias.

DISCUSSION

An exhaustive literature search was carried out applying language filters, high-quality indexed journals, year of publication, which ensures the best quality articles were included. Blood clot was the most used scaffold as is the most easy to place inside the canal and does not require to extract blood from the patient. The use of MTA and Biodentine as sealing materials has been associated with thickening of canal walls, apical closure and reduced signs and symptoms of apical periodontitis. However, most of the included reviews assessed were case reports and only in a few of them were clinical trials included. There is also a lack of risk of bias analysis in most reviews.

CONCLUSION

The blood clot is the most common scaffold used for inducing regeneration during the treatment of immature necrotic teeth. Tooth length increase and widening of root canal walls are the most common criteria used in the studies as success indicators. MTA and Biodentine did not show differences in the results analysed. Quality assessment and bias risk evaluation showed that it is necessary to design better studies with rigorous methodology to recommend a trustable and predictable protocol for the treatment of immature necrotic permanent teeth with periapical lesions.

REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO) CRD42021248404.

The Four Pillars for Successful Regenerative Therapy in Endodontics: Stem Cells, Biomaterials, Growth Factors, and Their Synergistic Interactions

Endodontics has made significant progress in regenerative approaches in recent years, thanks to advances in biologically based procedures or regenerative endodontic therapy (RET). In recent years, our profession has witnessed a clear conceptual shift in this therapy. RET was initially based on a blood clot induced by apical bleeding without harvesting the patient’s cells or cell-free RET. Later, the RET encompassed the three principles of tissue engineering, stromal/stem cells, scaffolds, and growth factors, aiming for the regeneration of a functional dentin pulp complex. The regenerated dental pulp will recover the protective mechanisms including innate immunity, tertiary dentin formation, and pain sensitivity. This comprehensive review covers the basic knowledge and practical information for translational applications of stem cell-based RET and tissue engineering procedures for the regeneration of dental pulp. It will also provide overall information on the emerging technologies in biological and synthetic matrices, biomaterials, and signaling molecules, recent advances in stem cell therapy, and updated experimental results. This review brings useful and timely clinical evidence for practitioners to understand the challenges faced for a successful cell-based RET and the importance of preserving or reestablishing tooth vitality. The clinical translation of these current bioengineering approaches will undoubtedly be beneficial to the future practice of endodontics.

The Understanding of Vital Pulp Therapy in Permanent Teeth: A New Perspective

The indications of vital pulp therapy (VPT) are expanding, which cases are suitable for VPT, and how to improve the success rate of VPT is a problem that often bothers us. The main purpose of VPT is to eliminate pulpitis by promoting the formation of reparative dentin or calcium bridge, so that it can continue to perform various physiological functions, and finally achieve the purpose of preserving pulp vitality and long-term preservation of affected teeth. Pulp capping and pulpotomy are the most common methods for VPT. The research field of VPT has attracted the attention of many scholars, who have studied it from many aspects (such as indications, material selection, operation requirements, and long-term prognosis). This article reviews the recent advances in the techniques of VPT in permanent teeth.

Pulp therapy and root canal treatment techniques in immature permanent teeth: an update

Background According to the Children's Dental Health Survey 2013, around one in ten children in Wales, Northern Ireland and England will have sustained dental trauma to a permanent incisor by the of age 15. Management of an exposed pulp in an immature permanent incisor is often urgent and has an impact on the long-term outcome of the tooth; therefore, it is essential that general dental practitioners feel confident in managing such a scenario to achieve an optimal outcome. This paper discusses the indications, technique, materials and outcomes.Aims This article aims to review the literature, which discusses various treatment modalities and materials for pulpal therapy and root canal treatment in the immature permanent tooth.Method Electronic searches were limited to English language, human studies, published within the past five years and the medical subject heading terms used were: direct pulp capping, apexogenesis, Cvek pulpotomy, full pulpotomy/pulpectomy, partial pulpotomy, apexification, non-vital pulp therapy and mineral trioxide aggregate apexification. Older, seminal articles identified through the references sections have also been included.Conclusion A number of options are available for the management of immature permanent teeth that have suffered an insult such as caries or trauma. This paper reviews the various methods of pulpal treatment, preservation therapy and root canal treatment options depending on the extent of the damage.

Do alternative scaffolds used in regenerative endodontics promote better root development than that achieved with blood clots?

The aim of this integrative review was to identify whether alternative scaffolds used in regenerative endodontics contribute to better root development, in relation to the increase in root length and thickness of dentin walls, compared with blood clot (BC) scaffolds. The literature search was conducted in PubMed, SciELO and Lilacs databases, using descriptors related to the topic. After applying the eligibility criteria, 11 articles were selected and analyzed according to the proposed aim. Five clinical and six in vivo studies, conducted in animals, compared different types of alternative scaffolds with BCs, with emphasis on platelet-rich plasma (PRP) and platelet-rich fibrin (PRF). All scaffolds, alternative or BC, promoted an increase in root length and dentin wall thickness, with varying percentages of increase between studies. In general, there was a significant increase in root length and dentin thickness promoted by PRF and PRP scaffolds, compared with BC. It was concluded that the majority of the scaffolds tested contributed to the increase in root length and thickness of dentin walls, with emphasis on PRF and PRP.

Continued root development of immature permanent teeth after regenerative endodontics with or without a collagen membrane: A randomized, controlled clinical trial

BACKGROUND

Recent studies evaluated the efficacy of a collagen membrane (Bio-Gide) to promote root development in regenerative endodontics (REPs). However, the influence of etiology and tooth type on the results was not assessed.

AIMS

To evaluate the quantitative and qualitative effect of a collagen membrane (Bio-Gide), with and without the effect of etiology and tooth type, in promoting root development in immature teeth after REPs.

DESIGN

Eighty nonvital immature teeth were divided randomly into two groups (40 teeth in each group). REPs were performed with (experimental group) and without (control group) a collagen membrane. All teeth were subjected to regular clinical and radiographical follow-up.

RESULTS

Seventy-six teeth were included in the final analyses. The average follow-up periods were 33.1 ± 21.8 months for the control group and 28.1± 18.6 months for the experimental group. Quantitative analysis of root development in the experimental group showed a greater increase in dentin wall thickness in the middle one-third of the root compared to the control group, with or without the effect of etiology and tooth type. Six types of root development were observed. There was no significant difference in the type of tooth development between the two groups.

CONCLUSION

The use of a collagen membrane could promote an increase in dentin wall thickness in the middle one-third of the root, and it had no significant effect in terms of the type of subsequent root development.

Effect of different intracanal medicaments on the fracture resistance of the human root

Background:

The effect of different intracanal medicaments on root fracture resistance has not been thoroughly investigated in the short and long term. To assess the effect of calcium hydroxide (CH), CH combined with Chlorhexidine (CHX), double antibiotic paste (DAP), and simvastatin as intracanal medicaments on the fracture resistance of the human root. One hundred and twenty single-rooted mandibular premolars which were extracted for periodontal reasons were collected for this in vitro study.

Materials and Methods:

This was an in vitro study. All teeth were decoronated. Root canals were prepared by the Pro taper system, and %2.5 NaOCl was used for irrigation. The smear layer was removed using %5.25 NaOCl and 17% ethylenediaminetetraacetic acid each for 3 min. The samples were randomly divided into five groups based on the medicament: (1) CH (2) CH + CHX (3) Simvastatin (4) DAP (5) Control group. All specimens in each group were incubated for 1 week (Subgroup A) and 1 month (Subgroup B). Then, medicaments were removed and filled with gutta-percha and AH26 sealer. All samples were tested for fracture resistance. The data were statistically evaluated with the SPSS software 17. ANOVA and Mann–Whitney U and Wilcoxon tests were used for the analysis of the data. P = 0.05 was considered statistically significant.

Results:

Although CH and CH + CHX increased the fracture resistance in a 1-week period, there was no significant difference between the groups after 1 month.

Conclusion:

Under the limitations of this study, CH and CH + CHX, DAP and simvastatin do not have a negative effect on root fracture resistance when used as intracanal medicaments for <1 month.

Root Canal Disinfection Articles with the Highest Relative Citation Ratios. A Bibliometric Analysis from 1990 to 2019

The relative citation rate (RCR) is a normalized article-level metric useful to assess the impact of research articles. The objective of this bibliometric study is to identify and analyze, in root canal disinfection, the 100 articles having the highest RCRs in the period 1990–2019, then compare them with the top 100 articles most cited. A cross-sectional study was performed, and the search strategy ((Disinfection AND root canal) AND ((“1990/01/01”[Date-Publication]: “2019/12/31”[Date-Publication]))) relied on PubMed (n = 4294 documents), and article data were downloaded from the iCite database. The 100 articles with the highest RCRs and the top 100 cited were selected and evaluated in bibliometric terms. Among the 100 articles with the highest RCRs, there were no differences in the three decades for RCRs values, but there were in citations, being 2000–2009 the most cited. The USA was the predominant country (n = 30), followed by Brazil (n = 14). The most frequent study designs were reviews (n = 27) and in vitro (n = 25) and ex vivo (n = 24) studies. All subfields were well represented, although they varied over time. In 2010–2019, regenerative procedures and irrigation/disinfection techniques were predominant. Considering the RCR’s top 100 articles, 76 were common with the 100 most cited articles. Using the RCR metric allowed us to identify influential articles in root canal disinfection, a research field with topics of significance that fluctuate over time. Compared to citations, RCR reduces the time from publication to detection of its importance for the readership and could be a valid alternative to citation counts.

Determination of crown discoloration and fluorescence induced by different medications used in regenerative endodontic procedures: An ex vivo study

Background

Crown discoloration is an undesirable side effect of the use of triple antibiotic paste (TAP) in regenerative endodontic procedures (REPs). The aim of this ex vivo study was to assess the potential for tooth discoloration and induction of fluorescence associated with the use of TAP containing either doxycycline (DOX) or clindamycin (CLIN), and of calcium hydroxide (Ca(OH)2), by spectrophotometric analysis and confocal laser scanning microscopy (CLSM).

Material and Methods

A total of forty single-rooted human teeth extracted by therapeutic indication were used. The root canals were enlarged using the step-back technique up to a K #80 file and were randomly divided into four experimental groups (10 specimens each): i)Ca(OH)2 group, ii)TAP with DOX group, iii) TAP with CLIN group, iv) Control group (no treatment). To quantify the change of color of the different groups of teeth included, the Vita Easyshade advance 4.0 spectrophotometer was used. CLSM was used to determine fluorescence.

Results

After 28 days of action inside the root canal, no extreme discoloration was visible, to the naked eye, in any of the teeth included in the study. Under the conditions of this ex vivo study, TAP with DOX induced the highest crown discoloration among the medicaments tested. In contrast, Ca(OH)2 and TAP with CLIN did not induce crown discoloration after 28 days. The TAP with DOX group presented the highest fluorescence measurements.

Conclusions

Considering the discoloration potential and fluorescence changes in TAP with DOX or other tetracyclines, and the cytotoxic effect of TAPs, we recommend the use of Ca(OH)2 for REPs.

Key words:Discoloration, doxycycline, clinadamycin, calcium hydroxide, endodontics.

Antimicrobial Efficacy of Triple Antibiotic Paste and Propolis as an Intracanal Medicament in Young Permanent Teeth: An In Vivo Study

Aim and objective

To evaluate the antimicrobial efficacy of triple antibiotic paste and propolis extracts as an intracanal medicament in young permanent teeth.

Materials and methods

A total of 30 single-rooted non-vital young permanent teeth with open apex were selected randomly from the children aged between 7 years and 14 years with no systemic complications. Group I—triple antibiotic paste and group II be propolis allocating 15 teeth in each group. After access opening, the first sample (S1) was collected by inserting paper point into the root canal, the second sample (S2) was collected immediately after irrigation, and the third sample (S3) was collected after post-intracanal medication after 3–4 weeks. Samples were sent for microbiological analysis to assess the bacterial count, and for the obtained data, statistical analysis was done.

Results

The mean colony count among the triple antibiotic paste group was 1906.75. After access opening, which was reduced to 315.12 after irrigation, and after 3–4 weeks, it was 817.25. There was a significant difference between sample 1, sample 2, and sample 3 (p value = 0.008). The mean colony count among the propolis group was 1427.87 after access opening, which was reduced to 436.00 after irrigation, and after 3–4 weeks, it has reduced to 252.37. There was a significant difference between sample 1, sample 2, and sample 3 (p value = 0.032). Intergroup comparison between the groups showed no statistical difference between the samples.

Conclusion

Propolis exhibited similar antimicrobial efficacy, which is comparable to triple antibiotic paste. So, propolis can be utilized as an intracanal medicament in young permanent teeth with an open apex.

Clinical significance

Propolis is a naturally occurring flavonoid-rich resinous product with antibacterial, antifungal, antiviral, immunomodulatory, and antioxidant effects. It is safe without any drug allergies and bacterial sensitivity and is a promising alternative to triple antibiotic paste for disinfecting non-vital young permanent teeth.

How to cite this article

Lillygrace E, Kethineni B, Puppala R, et al. Antimicrobial Efficacy of Triple Antibiotic Paste and Propolis as an Intracanal Medicament in Young Permanent Teeth: An In Vivo Study. Int J Clin Pediatr Dent 2021;14(2):243–248.

Efficacy of i-PRF in regenerative endodontics therapy for mature permanent teeth with pulp necrosis: study protocol for a multicentre randomised controlled trial

BACKGROUND

Dental pulp necrosis, a common health problem, is traditionally treated with root canal therapy; however, it fails in restoring the vitality of damaged pulp. Most studies regarding regenerative endodontic therapy (RET) are limited to the treatment of immature necrotic teeth. Given that injectable platelet-rich fibrin (i-PRF) has shown great potential in regenerative medicine as a novel platelet concentration, this study is designed to explore whether i-PRF can serve as a biological scaffold, extending the indications for RET and improving the clinical feasibility of RET in mature permanent teeth with pulp necrosis.

METHODS

This is a randomised, double-blind, controlled, multicentre clinical trial designed to evaluate the clinical feasibility of RET for mature permanent teeth with pulp necrosis and to compare the efficacy of i-PRF and blood clots as scaffolds in RET. A total of 346 patients will be recruited from three centres and randomised at an allocation ratio of 1:1 to receive RET with either a blood clot or i-PRF. The changes in subjective symptoms, clinical examinations, and imaging examinations will be tracked longitudinally for a period of 24 months. The primary outcome is the success rate of RET after 24 months. The secondary outcome is the change in pulp vitality measured via thermal and electric pulp tests. In addition, the incidence of adverse events such as discolouration, reinfection, and root resorption will be recorded for a safety evaluation.

DISCUSSION

This study will evaluate the clinical feasibility of RET in mature permanent teeth with pulp necrosis, providing information regarding the efficacy, benefits, and safety of RET with i-PRF. These results may contribute to changes in the treatment of pulp necrosis in mature permanent teeth and reveal the potential of i-PRF as a novel biological scaffold for RET.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04313010 . Registered on 19 March 2020.

Prospective cohort study of regenerative potential of non vital immature permanent maxillary central incisors using platelet rich fibrin scaffold

Regenerative endodontic procedures have gained momentum as a treatment modality of young immature permanent teeth. Literature reports reveal that platelet-rich fibrin (PRF) stimulates growth factors and induces regeneration. This study was undertaken to assess the regenerative potential of non-vital immature permanent maxillary central incisors using PRF with a follow-up for 2 yrs. 19 patients in the age group of 9–25 yrs with immature, non-vital permanent maxillary central incisors (n = 23) with/without signs and/or symptoms of periapical pathosis and open apex were included in this study. In the first appointment, access opening, canal disinfection and triple antibiotic paste placement were done. In the subsequent visit, PRF was prepared and placed inside the canal. Access was sealed with Mineral trioxide aggregate plug and composite. The patient was reviewed up to 24 mths. The mean difference was statistically analyzed using Friedman test followed by Dunn post hoc test and adjusted by Bonferroni correction (p < 0.05). As per AAE guidelines, the primary and secondary goals were achieved. A significant (p < 0.001) gradual increase in the root length, thickness of dentinal walls and decrease in apical diameter were observed. Within the limitations of this study, PRF placement was clinically and radiographically effective in inducing regeneration of non-vital immature permanent teeth.

Biocompatibility and Antibiofilm Properties of Calcium Silicate-Based Cements: An In Vitro Evaluation and Report of Two Clinical Cases

Simple Summary

Calcium silicate-based cements are successfully applied in the different fields of endodontics and vital pulp therapy. To better assess the properties of these bioactive materials, the present in vitro and in vivo study aimed to compare the biocompatibility and antibiofilm properties of ProRoot MTA and Biodentine. Human osteogenic sarcoma (Saos-2) cells were cultured in the presence of both materials and evaluated. Moreover, the bioactive cements were in vivo applied to perform vital pulp therapy on immature permanent teeth affected by reversible pulpitis. Saos-2 cells’ viability was slightly greater in the presence of ProRootMTA than Biodentine and cells would grow in a better way on ProRootMTA disks than on Biodentine ones. Moreover, ProRootMTA showed a powerful antibiofilm effect towards Streptococcus mutans. The in vitro results were clinically supported by a 100% success rate after 2 years of follow-up.

Abstract

Calcium silicate-based cements have reached excellent levels of performance in endodontics, providing predictable and successful results. To better assess the properties of these bioactive materials, the present study aimed to compare the biocompatibility and antibiofilm properties of ProRoot MTA and Biodentine. Human osteogenic sarcoma (Saos-2) cells were cultured on ProRoot MTA and Biodentine samples or in the presence of both cement extracts. Cell viability assay, measurement of reactive oxygen species (ROS), immunofluorescence analysis, as well as morphological evaluations were conducted. Moreover, Streptococcus mutans was used to assess the biofilm forming ability on ProRoot MTA and Biodentine disks. Finally, both cements were applied in vivo to treat immature permanent teeth affected by reversible pulpitis. Results: Cell viability assay demonstrated that Saos-2 cells had a dose- and time-dependent cytotoxicity to both analyzed cements, although cells exposed to ProRoot MTA showed a better cell vitality than those exposed to Biodentine (p < 0.001). Both cements demonstrated ROS production while this was greater in the case of Biodentine than ProRoot MTA (p < 0.001). Immunofluorescence images of the cytoskeleton and focal adhesions showed no differences in Saos-2 cells grown in the presence of ProRoot MTA eluate; whereas in the Biodentine groups, cells showed a morphology and focal adhesions more similar to that of the control sample, as the eluate concentration decreased. Morphological analysis revealed that Saos-2 cells were more flattened and exhibited better spreading when attached to ProRoot MTA disks than to Biodentine ones. The antibiofilm properties showed a time-dependent powerful inhibition of S. mutans superficial colonization and an antibiofilm effect of both cements. Clinically, complete root formation of the treated elements was achieved using the two studied cements, showing stable results over time. ProRoot MTA and Biodentine was demonstrated to be biocompatible and to possess antibiofilm properties. Their clinical application in vital pulp therapy provided successful outcomes after 2 years of follow-up.

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.

Antibiofilm Activity of Diclofenac and Antibiotic Solutions in Endodontic Therapy

INTRODUCTION

The aim of this study was to compare the antibiofilm effects of a triple antibiotic solution (TAS); a double antibiotic solution (DAS); and 5%, 2.5%, and 1.25% diclofenac solutions (DCSs) against Enteroccocus faecalis biofilm.

METHODS

Eighty-four sterile radicular dentin blocks were used as biofilm substrate for 3 weeks. The study groups were as follows: (1) 1 mg/mL TAS (minocycline, metronidazole, and ciprofloxacin), (2) 1 mg/mL DAS (metronidazole and ciprofloxacin), (3) 5% DCS, (4) 2.5% DCS, (5) 1.25% DCS, and (6) 0.9% saline solution. The antimicrobial activity was evaluated by bacterial count determinations and confocal laser scanning microscopy. The contact time for the antimicrobial tests was 5 minutes. Bacterial counts were expressed as the reduction percentage of colony-forming units; for the confocal laser scanning microscopic evaluation, the log₁₀ total biovolume and percentage of green population (live cells) were calculated.

RESULTS

The colony-forming unit reduction percentage ranged between 62.98 and 98.62, respectively, for TAS and 5% DCS. The DCS showed a concentration-dependent effect.For the confocal laser scanning microscopy, the log₁₀ total biovolume in all groups was very similar and showed a scarce (1.39-1.02) but significant reduction with respect to the control; 5% and 2.5% DCSs gave the lowest viable cell percentage. The TAS and DAS groups showed intermediate values without significant differences between them.

CONCLUSIONS

DCSs at 5% and 2.5% have greater antimicrobial effects than TAS and DAS and may be considered a valid alternative for controlling the infection of teeth with apical periodontitis.

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.

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

INTRODUCTION

Regenerative 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.

METHODS

Electronic 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.

RESULTS

Of 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.

CONCLUSIONS

Based 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.

A 5 years' follow-up of root anatomy-based maturogenesis achieved in infected immature molars using regenerative techniques - A case series

Infected immature molars are commonly encountered but seldom are they treated using principles of regenerative endodontics. The case series describes a feasible technique for attempting maturogenesis based on molar tooth anatomy. A total of 9 infected immature molars in the patients between 6 and 18 years of age were treated as part of this case series. All the canals were disinfected using 3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid following minimal instrumentation. After using triple antibiotic paste for 3 weeks, bleeding was induced in mesial or constricted canals and platelet-rich fibrin was placed in distal or open wide canals till the orifice level. Coronal seal was obtained using mineral trioxide aggregate. Outcome was evaluated clinically and radiographically at the periods of 3, 6, 12, 24, 36, and 60 months. All the teeth showed continued root development and maintained functionality but none responded to vitality testing. Anatomical aspects of individual roots within a tooth can be utilized as a guide to decide the appropriate approach for attempting maturogenesis in a molar. Root changes can be expected even if the pulp vitality is not restored.

Different Approaches to the Regeneration of Dental Tissues in Regenerative Endodontics

(1) Background: The regenerative procedure has established a new approach to root canal therapy, to preserve the vital pulp of the tooth. This present review aimed to describe and sum up the different approaches to regenerative endodontic treatment conducted in the last 10 years; (2) Methods: A literature search was performed in the PubMed and Cochrane Library electronic databases, supplemented by a manual search. The search strategy included the following terms: “regenerative endodontic protocol”, “regenerative endodontic treatment”, and “regenerative endodontics” combined with “pulp revascularization”. Only studies on humans, published in the last 10 years and written in English were included; (3) Results: Three hundred and eighty-six potentially significant articles were identified. After exclusion of duplicates, and meticulous analysis, 36 case reports were selected; (4) Conclusions: The pulp revascularization procedure may bring a favorable outcome, however, the prognosis of regenerative endodontics (RET) is unpredictable. Permanent immature teeth showed greater potential for positive outcomes after the regenerative procedure. Further controlled clinical studies are required to fully understand the process of the dentin–pulp complex regeneration, and the predictability of the procedure.

Clinical cell-based versus cell-free regenerative endodontics: clarification of concept and term

There is no consensus on the true meaning of clinical regenerative endodontics, and there is confusion over the concept and the term. Commonly used terms include revitalization and revascularization. The clinical methods for endodontic revitalization procedures and the tissue engineering concept differ depending on whether there is exogenous delivery of cells - called cell therapy, or not. Here, in this review, the difference is clarified by emphasizing the correct terminology: cell-free versus cell-based regenerative endodontic therapy (CF-RET versus CB-RET). The revitalization procedures practised clinically do not fit into the modern tissue engineering concepts of pulp regeneration but can be categorized as CF-RET. The modern tissue engineering concept in pulp regeneration is a CB-RET, which so far is at the clinical trial stage. However, histological examination of teeth following regenerative endodontic treatments reveals healing with repair derived from stem cells that originate from the periodontal, bone and other tissues. The aim of regenerative endodontics is regeneration of the pulp-dentine complex. This review discusses why CF-RET is unlikely to regenerate a pulp-dentine complex with current protocols. The American Association of Endodontists and the European Society of Endodontology have not yet recommended autologous stem cell transplantation (CB-RERT) which aspires for regeneration. Therefore, an understanding of the concept, term, difficulties and differences in current protocols is important for the clinician. However, rather than being discouraged that ideal regeneration has not been achieved to date, repair can be an acceptable outcome in clinical regenerative endodontics as it has also been accepted in medicine. Repair should also be considered in the context that resolution of the clinical signs/symptoms of pulp necrosis/apical periodontitis is generally reliably obtained in clinical regenerative endodontics.

Effects of lipopolysaccharide on proliferation, migration and osteogenic differentiation of apical papilla cells from early and late stage of root development

The aim of this study was to investigate the effects of lipopolysaccharide on cell proliferation, migration and osteogenic differentiation of apical papilla cells from early and late stage of root development. After challenging with various lipopolysaccharide concentrations to apical papilla cells from both stages of root development for 168 h, cell proliferation and migration were investigated. Osteogenic differentiation was examined by Alizarin red staining, and gene expressions of bone/cementum or dentin-related genes were examined by polymerase chain reaction. Lipopolysaccharide did not affect cell proliferation and migration in both groups. Lipopolysaccharide at 1 and 5 µg mL^-1 increased Alizarin red staining in apical papilla cells from early-stage but not the late-stage cells. Bone sialoprotein (bone/cementum marker) gene expression increased in both early and late stage of root development at 5 µg mL^-1 . These results might explain bone/cementum generation in regenerative endodontic procedures.

Cytotoxic, migration, and angiogenic effects of intracanal irrigants on cells involved in revascularization of immature teeth

OBJECTIVE

To evaluate protocols of root canal irrigation and dentin pretreatment in a cell culture model simulating immature teeth. Cytotoxic, migration, and angiogenic effects of Sodium hypochlorite associated with EDTA (NaOCl/EDTA), NaOCl associated with Smear Clear (NaOCl/SC), and QMix were compared.

DESIGN

Three roots of mandibular first premolars had their length and root canal diameter standardized. Root canals were irrigated, and the resulting solutions were diluted in culture medium. Sulforhodamine B (SRB) assay was performed with apical papilla cells and with endothelial cells (HUVECs) to assess cytotoxicity. Polarity index and migration assays of apical papilla cells and sprouting of HUVECs were evaluated. Data were analyzed by ANOVA and Tukey post-hoc tests (p < .05).

RESULTS

In apical papilla cells, NaOCl/SC and QMix promoted higher cytotoxicity, decreased fraction of elongated cells, and had lower migration speed and shorter migration distance of cells compared to NaOCl/EDTA. Also, HUVECs treated with NaOCl/SC and QMix showed decreased tubule formation in comparison with NaOCl/EDTA.

CONCLUSIONS

NaOCl/SC and QMix showed unfavorable biological responses of cells involved in revascularization in comparison to NaOCl/EDTA. Further studies with other intracanal irrigants should be performed to improve the balance of root canal disinfection with biological responses.

Dentin-Pulp Tissue Regeneration Approaches in Dentistry: An Overview and Current Trends

Conventional treatment approaches in irreversible pulpitis and apical periodontitis include the disinfection of the pulp space followed by filling with various materials, which is commonly known as the root canal treatment. Disadvantages including the loss of tooth vitality and defense mechanism against carious lesions, susceptibility to fractures, discoloration and microleakage led to the development of regenerative therapies for the dentin pulp-complex. The goal of dentin-pulp tissue regeneration is to reestablish the physiological pulp function such as pulp sensibility, pulp repair capability by mineralization and pulp immunity. Recent dentin-pulp tissue regeneration approaches can be divided into cell homing and cell transplantation. Cell based approaches include a suitable scaffold for the delivery of potent stem cells with or without bioactive molecules into the root canal system while cell homing is based on the recruitment of host endogenous stem cells from the resident tissue including periapical region or dental pulp. This review discusses the recent treatment modalities in dentin-pulp tissue regeneration through tissue engineering and current challenges and trends in this field of research.

Regenerating the Pulp-Dentine Complex Using Autologous Platelet Concentrates: A Critical Appraisal of the Current Histological Evidence

Background:

Autologous platelet concentrates such as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) have gained overwhelming popularity in regenerative endodontics. Clinical evidence reveals the lack of a particular advantage of using PRP or PRF over an evoked blood clot in promoting canal wall thickening and/or continued root development in immature necrotic teeth. Moreover, despite stimulating tissue repair and repopulating the root canals of immature and mature permanent teeth, the new vital tissue may not possess the functional activity of the native pulp tissue.

Methods:

To better understand the origin, nature, and long-term fate of the tissue types found within the pulp space, we critically examine all available histo-/morphological evidence for pulp–dentine complex regeneration using PRP and/or PRF, alone or together with an evoked blood clot, specialised or unspecialised primary cells, and other biomaterials.

Results:

Histological data from clinical studies is scant. Reportedly, the inner dentinal surface supports cementum-like tissue formation, but this interface likely deviates in structure and function from the native cementodentinal junction. Presence of bone-like tissue within the pulp space is intriguing since de novo osteogenesis requires closely coordinated recruitment and differentiation of osteoprogenitor cells. Compared to untreated necrotic teeth, an evoked blood clot (with/without PRF) improves fracture resistance. Tooth regeneration using PRF and dental bud cells is unreliable and the constituent neoformed tissues are poorly organised.

Conclusion:

PRP/PRF fail to demonstrate a significant advantage over an induced blood clot, alone. The true nature of neoformed tissues remains poorly characterised while their response to subsequent insult/injury is unexplored.

12-Year Follow-Up of Regenerative Endodontic Treatment of Immature Permanent Upper Incisors with Acute Abscess

This case report discusses the endodontic treatment of a 7-year-old girl who suffered trauma (intrusion) to the immature upper central incisors secondary to a fall from a bicycle. Thirty days after the accident the patient was brought by her mother for clinical and radiographic assessment with a chief complaint of swelling and tenderness to percussion and palpation. Acute apical abscess associated with immature teeth were diagnosed. A decision was made to perform regenerative endodontic treatment. Access cavities were made and the root canals were disinfected by irrigation with 2.5% sodium hypochlorite. Final irrigation was performed with 17% EDTA. Due to pain and presence of secretions, 2% chlorhexidine gel was applied as an intracanal medicament. Seven days later, at the second visit, the root canals were once again disinfected and the canals of the right and left permanent upper central incisors were filled with double antibiotic paste (metronidazole/ciprofloxacin) and calcium hydroxide paste, respectively. Zinc oxide was mixed in both pastes. At the third visit, after 21 more days, the pastes were removed and the periapical areas were stimulated with a #80 K-file to encourage clot formation within the pulp cavities. A mineral trioxide aggregate (MTA) paste cervical plug was placed and the teeth were restored with glass ionomer cement. Radiographs and CBCT scans demonstrated complete root formations. The patient has been followed for 12 years, with evidence of clinical success throughout.

Coronal Tooth Discoloration After the Use of White Mineral Trioxide Aggregate

Mineral trioxide aggregate (MTA) has been used in regenerative procedures but observations have indicated that with its use there is dark staining of the tooth structure. This case report describes the treatment of tooth discoloration caused by white mineral trioxide aggregate (WMTA). Revascularization was performed with the use of WMTA in the upper left central incisor. Grayish discoloration appeared 9 months later, the tooth necessitating internal bleaching of the tooth. A significant improvement was observed in the crown after internal bleaching. The choice of material should not rely solely on biological and functional aspects, but aesthetic considerations should also be taken into account. The patient needs to be advised of risks, benefits, and alternatives to internal bleaching, eg, a veneer or a crown. Coronal discoloration is a significant distraction and embarrassment for many people in achieving an aesthetic smile; thus, it must be corrected at the earliest possible stage of discoloration.

Cytotoxic, Migration, and Angiogenic Effects of Photodynamic Therapy and Photobiomodulation Associated with a Revascularization Protocol

INTRODUCTION

This study evaluated photodynamic therapy (PDT) and photobiomodulation therapy (PBM) as adjuncts to pulp revascularization using cultures of apical papilla cells (APCs) and endothelial cells (HUVECs).

METHODS

The root canal and apical foramen of 2 mandibular first premolars were enlarged to simulate immature teeth. The canal of 1 tooth was filled with 1 mL 0.005% methylene blue (MB). After that, the canals of both teeth were irrigated with 20 mL 1.5% sodium hypochlorite (NaOCl) and 20 mL 17% EDTA. The resulting solutions were diluted in cell culture media at a concentration of 0.5% (0.5% MB + NaOCl + EDTA and 0.5% NaOCl + EDTA). After PDT (0.5% MB + NaOCl + EDTA + PDT) and PBM (0.5% NaOCl + EDTA + PBM) applications, the effects were evaluated to determine cytotoxicity, polarity index, APC migration, and HUVEC sprouting, and results were compared with those of their controls (solutions without laser application). Cell culture media (CT) was also used as a control. Data were analyzed using 1-way analysis of variance and the Tukey post hoc test (P ≤ .05).

RESULTS

PDT and PBM promoted greater APC viability than their controls, and PDT had greater cell viability than CT (P < .05). All protocols reduced APC migration when compared with CT (P < .05). HUVEC sprouts grown out of spheroids in PBM had a greater ratio area than their control (P ≤ .01), and the PDT ratio of the spheroid area was similar to that of its control (P > .05).

CONCLUSIONS

PBM and PDT seem to be potentially effective adjuncts to revascularization in nonvital immature teeth.

Trigeminal Sensory Neurons and Pulp Regeneration

The pulp-dentin complex is innervated by a high density of trigeminal neurons free nerve endings. These neuronal fibers are highly specialized to sense noxious stimuli such as thermal, mechanical, chemical, and biological cues. This robust alert system provides immediate feedback of potential or actual injury triggering reflex responses that protect the teeth from further injury. In the case of patients, pain is the most important experience that leads them to seek oral health care. The adequate removal of the etiology, such as caries, provides ample opportunity for the robust reparative and regenerative potential of the pulp-dentin complex to restore homeostasis. In addition to this elaborated surveillance system, evidence has accumulated that sensory neuronal fibers can potentially modulate various steps of the reparative and regenerative process through cellular communication processes. These include modulation of immunologic, angiogenic, and mineralization responses. Despite these orchestrated cellular events, the defense of the pulp-dentin complex may be overwhelmed, resulting in pulp necrosis and apical periodontitis. Regenerative endodontic procedures have evolved to restore the once lost function of the pulp-dentin complex. After these procedures, a large subset of successful cases demonstrates a positive response to sensitivity testing, suggesting reinnervation of the canal space. This process is likely mediated through cellular and noncellular release of neurotrophic factors such as brain-derived nerve growth factor. In addition, these newly recruited nerve fibers appear equipped to sense thermal stimuli through nonhydrodynamic mechanisms. Collectively, the significance of innervation in the normal physiology of the pulp-dentin complex and its role in regeneration need to be better appreciated to promote further research in this area that could potentially bring new therapeutic opportunities.