Regenerative Endodontic Procedures, Disinfectants and Outcomes: A Systematic Review

Final irrigation with bioglass solution in regenerative endodontic procedure induces tissue formation inside the root canals, collagen maturation, proliferation cell and presence of osteocalcin

AIM

To evaluate the influence of an experimental solution of cobalt-doped F18 bioactive glass (F18Co) on tissue repair following regenerative endodontic procedure (REP) in rat molars.

METHODOLOGY

The F18Co solution was prepared at a ratio of 1:5 F18Co powder to distilled water. The right or left upper first molars of 12 Wistar rats were used, where the pulps were exposed, removed, and irrigated with 2.5% sodium hypochlorite (NaOCl), followed by 17% ethylenediaminetetraacetic acid (EDTA) (5 min each). Subsequently, the molars were divided into two groups (n = 6): REP-SS and REP-F18Co, where they received a final irrigation (5 min) with saline solution (SS) or F18Co solution, respectively. Then, intracanal bleeding was induced, and the tooth was sealed. Untreated molars were used as controls (n = 3). At 21 days, the rats were euthanized, and the specimens were processed for analysis of mineralized tissue and soft tissue formation inside the root canal using haematoxylin-eosin. The presence and maturation of collagen were evaluated by Masson's trichrome and picrosirius red staining. Immunolabelling analyses of proliferating cell nuclear antigen (PCNA) and osteocalcin (OCN) were performed. The data were submitted to the Mann-Whitney U-test (p < .05).

RESULTS

There was a similar formation of mineralized tissue in thickness and length in REP-SS and REP-F18Co groups (p > .05). Regarding the presence of newly formed soft tissue, most specimens of the REP-F18Co had tissue formation up to the cervical third of the canal, whilst the REP-SS specimens showed formation up to the middle third (p < .05), and there was higher maturation of collagen in REP-F18Co (p < .05). The number of PCNA-positive cells found in the apical third of the root canal was significantly higher in the F18Co group, as well as the OCN immunolabelling, which was severe in most specimens of REP-F18Co, and low in most specimens of REP-SS.

CONCLUSION

The final irrigation with F18Co bioactive glass solution in REP did not influence mineralized tissue formation but induced soft tissue formation inside the root canals, with higher collagen maturation, and an increase in PCNA-positive cells and OCN immunolabelling.

Effect of rapamycin on human periodontal ligament stem cells that have been exposed to sodium hypochlorite

AIMS

The present study investigated the effect of rapamycin on the viability and osteogenic differentiation potential of human periodontal ligament stem cells (hPDLSCs) in the presence of sodium hypochlorite (NaOCl).

MAIN METHODS

After determining the minimum inhibitory concentration of NaOCl and optimum concentration of rapamycin, the viability of hPDLSCs was evaluated using the MTT assay subsequent to their exposure to NaOCl, rapamycin, or a combination of both. Osteogenic differentiation was evaluated by the cell mineralization assay performed by alizarin red S staining, alkaline phosphatase activity, and monitoring the expression of osteogenic genes markers Runt-related transcription factor 2, osteocalcin, and osteoprotegerin, using real-time quantitative polymerase chain reaction (RT-qPCR). The expression of autophagy-related genes PI3K, Akt, and mTOR, was also analyzed with RT-qPCR.

KEY FINDINGS

Stem cells treated with rapamycin showed the highest percentage of viable cells in the presence of NaOCl. The same trend was observed for all osteogenic differentiation assays. The hPDLSCs treated with rapamycin demonstrated the highest calcium nodule deposition, alkaline phosphatase activity, and the expression of osteogenic gene markers. These effects were not adversely affected by the presence of NaOCl. Rapamycin significantly inhibited mTOR gene expression, while there were no differences in the gene expression of PI3K and Akt.

SIGNIFICANCE

Rapamycin counteracts the cytotoxic effect of NaOCl by enhancing the viability and osteogenic differentiation potential of hPDLSCs. Rapamycin appears to accomplish these processes via autophagy activation, by inhibiting mTOR gene expression. The incorporation of rapamycin in regenerative endodontic therapy may encourage a higher success rate.

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.

Morphological Interface Between Restorative and Pulp-Capping Materials: A Systematic Review

Background

Bioceramic materials (BCMs) are widely used in vital pulp therapy (VPT) for their biocompatibility and bioactivity; however, their mechanical properties are equally important in the clinical outcome of the pulp-capped teeth.

Objective

To carry out an analysis of the research produced on the morphology of the interface between BM and restorative materials (RM) through a systematic review.

Methodology

An electronic search was performed in Scopus, PubMed, and Web of Science until December 9, 2022. The keywords used in combination with truncation and Boolean operators were: (morphology OR filtration OR porosity) AND (silicate OR composite) AND (cement) AND ("pulp capping" OR "vital pulp therapy" OR "vital pulp treatment").

Results

Of the 387 articles initially retrieved from the electronic search databases, 5 articles met the criteria for qualitative data collection. MTA and Biodentine were the most studied BCMs. All the articles used a scanning electron microscope as a method of evaluating the samples. Sample sizes and setting times of RM and BCMs differed between studies. Three out of 5 studies used similar conditions of recorded temperature and humidity of 37°C and 100%, respectively.

Conclusion

The different biomaterials used, the application of adhesive systems, humidity and restoration time affect the bonding performance and the ultrastructural interface between BCMs and RMs. The scarcity of research on this point makes it necessary to delve into it and study new materials to obtain more scientific evidence.

Clinical and radiographic evaluation of NeoMTA versus conventional white mineral trioxide aggregate in revascularization of non-vital immature permanent anterior teeth (A randomized controlled trial)

OBJECTIVE

To evaluate and compare clinically and radiographically the effect of using two different coronal plug materials (NeoMTA versus Conventional White mineral trioxide aggregate) in revascularization of non-vital immature permanent anterior teeth, with special reference to the assessment and evaluation of discoloration potential over a period of one year.

METHODS

Revascularization procedure was performed in (30) immature permanent non-vital anterior teeth which were randomly allocated to two equal groups (n = 15). NeoMTA was used as coronal plug material in the Experimental Group (N), while conventional White mineral trioxide aggregate (WMTA) was used as a coronal plug material in the Control Group (W). All treated teeth were evaluated clinically at 1 week, 1, 3, and 12 months and radiographically at 12 months.

RESULTS

The overall clinical and radiographic success rate of Groups (N) and (W) at the end of the 12-month follow-up period was 100%. The discoloration was detected in a single tooth (9.1%) in Group (N) and three teeth (27.3%) in Group (W) but the difference between groups was not statistically significant.

CONCLUSIONS

Both NeoMTA and conventional WMTA were successful coronal plug materials in the revascularization of non-vital immature permanent teeth achieving a high level of clinical and radiographic success. NeoMTA is a promising coronal plug material that can be used for revascularization procedures in the esthetic zone as it showed less discoloration potential compared with conventional WMTA, however, there was no statistically significant difference between both materials.

Outcomes reporting in systematic reviews on revitalization: A scoping review for the development of a core outcome set

BACKGROUND

Revitalization is a type of regenerative endodontic treatment (RET) that offers the exciting prospect of revitalizing damaged tissue, therefore improving outcomes for non-vital immature teeth. To evaluate its potential, there needs to be consistency in outcome reporting of clinical studies investigating revitalization to allow for evidence synthesis and inform clinical decision making.

OBJECTIVES

The aim of this scoping review was to identify outcomes that are reported in systematic reviews on revitalization including how and when these outcomes are measured. Additionally, evidence of selective reporting bias in the reviews was assessed.

METHODS

A comprehensive electronic search of healthcare databases and grey literature was conducted to identify systematic reviews published in the English language reporting outcomes of revitalization in permanent immature teeth. There was no restriction on the date of publication. Outcome data was extracted by four reviewers independently and mapped with a healthcare taxonomy into five core areas: survival, clinical/physiological changes, life impact, resource use and adverse events. Selective reporting bias and how it was measured was assessed independently by two reviewers.

RESULTS

Twenty-six systematic reviews were included in this scoping review. There was lack of standardization in reporting and significant heterogeneity across reviews in outcome endpoints. The outcomes reported could be aligned within the five core areas of the taxonomy including tooth survival which was reported in nine reviews. Patient-reported outcomes were generally limited and no review reported on Oral Health Related Quality of Life. Many of the reviews reporting on randomized control trials were at low risk of selective reporting bias whilst other study designs were at higher risk.

DISCUSSION

Consistency in outcome reporting is necessary to realize the benefits of old but particularly novel therapies. Data from this review confirmed heterogeneity in reporting outcomes of revitalization and the need for development of a core outcome set (COS).

CONCLUSIONS

Several important outcomes including survival, root development, tooth discolouration and periapical healing have been identified in this review which could inform the development of a COS in this area.

REGISTRATION

Core Outcome Measures in Effectiveness Trials (COMET) database (registration no. 1879).

Regenerative Endodontic Procedures in Immature Permanent Teeth With Dental Trauma: Current Approaches and Challenges

After dental trauma to immature permanent teeth (IPT), there can be pulpitis, necrotic, and periapical periodontitis, which will halt further root development. Traditional endodontic root canal treatments and apexification cannot revitalize the necrotic pulp to revitalize the tooth to promote further root development. As a consequence, IPT with thin dentinal walls can be prone to fracture and if a fracture occurs, the patient will likely suffer the loss of the tooth. In an attempt to save IPT, there has been a growing interest among dentists to use regenerative endodontic procedures (REPs) to revitalize a replace dental pulp to continue root development and strengthen the dentinal walls to help prevent a subsequent loss of the tooth. However, the effectiveness of REPs and the precise methods to successfully accomplish REPs are controversial. Therefore, the objective of this review is to compare the different approaches to REPs in case reports by highlighting their advantages and limitations.

Conceptual combination of disinfection in regenerative endodontics: Conventional versus laser-assisted disinfection

Background:

Successful regeneration depends on four key elements of tissue engineering such as stem cells, growth factors, scaffold and sterile environment. Therefore, regenerative endodontic therapy requires higher degree of disinfection for successful outcomes.

Aims and Objective:

To evaluate the clinical and radiographic outcome using conventional and laser assisted disinfection in regenerative endodontics at 1, 3 and 6 months.

Materials and Methods:

18 children with necrotic young permanent teeth were selected for the study. In Group A, in the first appointment AAE (American Association of Endodontics, Clinical Consideration for Regenerative Endodontic Procedure - 2016) disinfection protocol was employed. In Group B laser assisted disinfection (810 nm diode laser, 1 W, 20 ms Pulse length and 20 ms interval duration) was performed. Microbial samples were obtained before and after disinfection to check the level of disinfection. The cases were followed up at 1 month, 3 months and 6 months interval and evaluated for clinical outcome, periapical healing and apical response. Data were statistically analyzed with level of significance set 1% or 5% accordingly (P<0.01 or P<0.05)

Results:

On intragroup comparison there was significant reduction in bacterial count before and after disinfection with respect to laser assisted disinfection group. (P value = 0.007) There was no significant change in the clinical outcome score in laser group at 1,3- and 6-months interval. Periapical healing score showed statistically significant results in laser group when followed from 3 months to 6 months (P value = 0.04).

Conclusion:

Along with AAE 2016 protocol, use of laser assisted disinfection resulted in improved quality of disinfection and an expeditious clinical outcome and periapical healing in necrotic young permanent teeth. Keywords: Disinfection; laser; regenerative endodontics; sodium hypochlorite; tooth apex

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.

Regenerative Endodontic Procedures: An Umbrella Review

The Regenerative Endodontic Procedure (REP) is a biologically based method in which a damaged pulp-dentin complex is replaced by a new vital tissue. This umbrella review aimed to critically assess the available systematic reviews (SRs) on REP. An electronic database search was conducted (PubMed-Medline, CENTRAL, Scielo, Web of Science, and LILACS) until December 2020. Studies were included if they were an SR on REP. The Risk of Bias (RoB) of SRs was analyzed using the Measurement Tool to Assess SRs criteria 2 (AMSTAR2). The primary outcome was the methodological quality in each specific section of REP protocols and outcomes. From 403 entries, 29 SRs were included. Regarding the methodological quality, ten studies were of critically low, three of low, fourteen of moderate, and two were rated as high quality. The quality of evidence produced by the available SRs was not favorable. Future high standard SRs and well-designed clinical trials are warranted to better elucidate the clinical protocols and outcomes of REP.