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

Top 100 most-cited scientific articles in regenerative endodontics 2019-2023: A bibliometric analysis

BACKGROUND

Bibliometric analysis is a critical indicator of the influence and relevance of scientific papers, whilst also highlighting key contributors and gaps in knowledge in a scientific field.

OBJECTIVES

To update and analyse the 100 most-cited papers in regenerative endodontics from 2019 to 2023.

METHODS

A search of the most-cited recent papers focusing on regenerative endodontics using journals included in the category, 'Dentistry, Oral Surgery & Medicine', in the Clarivate Web of Science database from 2019 to 2023 was performed. Three researchers conducted the study selection and data extraction. Data extraction included publication title and year, authors, number and mean number of citations, institution, country and continent, study design, journal title, keywords and research topic. Citation counts were also collected in Google Scholar and Scopus databases. Graphical bibliometric networks were created using VOSviewer software.

RESULTS

The number of citations of the 100 most-cited articles ranged from 6 to 85. Most were published in 2020 (n = 48), principally in the Journal of Endodontics (47%), followed by International Endodontic Journal (13%), Journal of Dental Research (6%) and Dental Materials (6%). Laboratory study was the most common study design amongst the included papers (n = 47), followed by narrative reviews (n = 17) and observational studies (n = 16). The most frequent first author on the top three most-cited papers was Hacer Aksel, whilst Adham A. Azim (n = 6; 89 citations) contributed most to the top 100 articles. The institution from which most articles originated was the University of Hong Kong (China) (n = 5; 81 citations), whereas the corresponding authors were predominantly from the United States of America (USA) (n = 31; 560 citations). The VOSviewer map of co-authorship demonstrated research collaborative clusters. 'Regenerative endodontics' and 'stem-cells' were the most employed keywords (37 and 36 occurrences respectively).

DISCUSSION

The current study was designed not only to showcase the most influential papers in regenerative endodontics since 2019 but also to provide a better understanding of global research in this area over the last five years.

CONCLUSIONS

This bibliometric analysis highlighted papers, authors, institutions and keywords in regenerative endodontics. The 100 most-cited papers primarily consisted of laboratory studies published in the USA, focusing on evaluating biomaterials and scaffold design strategies in contact with stem cells. Clinical studies and systematic reviews representing higher levels of scientific evidence are currently not the most influential in the regenerative endodontic field.

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.

The capability of regenerative endodontics to promote the complete root formation in immature permanent teeth with different initial pre-operative conditions

OBJECTIVES

To describe the potential possibility of complete root formation after regenerative endodontic procedures (REPs) in immature permanent teeth with different initial pre-operative conditions.

MATERIALS AND METHODS

Children who underwent REPs in the Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, Beijing, China, from January 2013 to December 2022 were enrolled. Whether the tooth achieved complete root formation was determined using post-operative periapical radiography. The potential possibility of complete root formation after REPs in immature permanent teeth with different initial conditions is discussed.

RESULTS

A total of 428 teeth from 401 patients were included, of which 258 (60.2%) achieved complete root formation. In cases that achieved complete root formation, the most serious type of trauma was avulsion, the teeth with the worst initial root development were less than one-third of the development (stages 6-7), and the longest duration of the presence of apical lesions in the tooth before the first visit was more than 180 days. There is a significant difference in the root formation of teeth with different initial developmental stages and diagnoses.

CONCLUSIONS

The active period of continued root formation was 5-21 months post-operatively. The higher the initial stage of root development and the shorter the duration of the presence of apical lesions in the tooth before the first visit, the greater the possibility of root formation. However, complete root formation may still be expected after REPs in severely injured immature permanent teeth and teeth with poor initial pre-operative root development conditions (less than stage 7) at the first visit. This is also true for teeth with long-term and large-scale apical lesions.

Analysis of the achievement of primary and secondary goals and influencing factors in single-rooted immature permanent teeth after regenerative endodontic procedures: a retrospective study

OBJECTIVE

This study explored the achievement of primary and secondary goals and factors influencing their achievement in regenerative endodontic procedures (REPs) for immature permanent teeth.

METHODS

Dental records of all patients who received REPs for immature permanent teeth at the Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology between January 2012 and January 2023 were retrieved. The evaluation of the primary goal was based on medical and radiographic records. The achievement of the primary goal was defined as the absence of clinical signs and symptoms, such as pain, swelling, or sinus tract and the absence of periapical radiolucency, as assessed on postoperative periapical radiographs. The achievement of secondary goal represented increased root wall thickness and/or increased root length, that is, continued root development. Periapical radiographs before and after treatment were used to evaluate the achievement of the secondary goal. The secondary goal was required to be achieved alongside the achievement of primary goal.

RESULTS

A total of 436 teeth (136 anterior and 300 posterior teeth) were included in this study, 96.1% of which demonstrated achievement of the primary goal. Signs of failure (17 teeth) included crown fracture and uncontrolled and recurrent periapical lesions. In addition, 77.8% of teeth demonstrated achievement of the secondary goal, and more than half of the teeth exhibited a complete root development. Evaluation factors included patients' age, sex, tooth type, etiology, preoperative periapical lesion, duration of clinical signs and symptoms, follow-up period, and stage of root development. The achievement of the primary and secondary goals were significantly related to age and tooth type (p < 0.05).

CONCLUSIONS

Children with a younger initial visit age are more likely to achieve primary and secondary goals. Additionally, posterior teeth had an advantage over anterior teeth in achieving primary and secondary goals.

Combination of metformin and double antibiotic paste for the regeneration of non-vital immature teeth: a preliminary randomized clinical study

BACKGROUND

The present study aimed to investigate whether incorporating metformin in double antibiotic paste (DAP) can promote the regeneration process of non-vital immature teeth.

METHODS

Out of 32 pediatric patients undergoing regenerative endodontic procedures (REPs), 6 cases with a follow-up period of less than 12 months or lack of documentation were excluded then the remaining 26 were analyzed. 15 cases received DAP, and 11 cases received a DAP + metformin as the intra-canal medicament, kept for an average of 23 days. During 18 months of follow-up, clinical and radiographic examinations were performed to evaluate the treatment outcomes based on the resolution of apical periodontitis, root development, and the occurrence of intracanal calcification. The chi-square test was used for the statistical analysis (P < 0.05).

RESULTS

All patients demonstrated resolution of apical periodontitis; however, complete apical closure was only seen in 50% of the patients. The rate of apical closure and root length was significantly higher in the DAP + metformin group (P = 0.047), although the two groups were not significantly different in terms of root width (P = 0.184). Canal obliteration was seen in 15% of cases, all of which were in the DAP group.

CONCLUSIONS

According to the present findings, metformin could promote root development in the regeneration process when incorporated in DAP.

TRIAL REGISTRATION

This clinical trial was registered on the Iranian Registry of Clinical Trials (IRCT20200120046197N1) on 26.2.2021.

Epigenetic therapeutics in dental pulp treatment: Hopes, challenges and concerns for the development of next-generation biomaterials

This opinion-led review paper highlights the need for novel translational research in vital-pulp-treatment (VPT), but also discusses the challenges in translating evidence to clinics. Traditional dentistry is expensive, invasive and relies on an outmoded mechanical understanding of dental disease, rather than employing a biological perspective that harnesses cell activity and the regenerative-capacity. Recent research has focussed on developing minimally-invasive biologically-based 'fillings' that preserve the dental pulp; research that is shifting the paradigm from expensive high-technology dentistry, with high failure rates, to smart restorations targeted at biological processes. Current VPTs promote repair by recruiting odontoblast-like cells in a material-dependent process. Therefore, exciting opportunities exist for development of next-generation biomaterials targeted at regenerative processes in the dentin-pulp complex. This article analyses recent research using pharmacological-inhibitors to therapeutically-target histone-deacetylase (HDAC) enzymes in dental-pulp-cells (DPCs) that stimulate pro-regenerative effects with limited loss of viability. Consequently, HDAC-inhibitors have the potential to enhance biomaterial-driven tissue responses at low concentration by influencing the cellular processes with minimal side-effects, providing an opportunity to develop a topically-placed, inexpensive bio-inductive pulp-capping material. Despite positive results, clinical translation of these innovations requires enterprise to counteract regulatory obstacles, dental-industry priorities and to develop strong academic/industry partnerships. The aim of this opinion-led review paper is to discuss the potential role of therapeutically-targeting epigenetic modifications as part of a topical VPT strategy in the treatment of the damaged dental pulp, while considering the next steps, material considerations, challenges and future for the clinical development of epigenetic therapeutics or other 'smart' restorations in VPT.

Evaluation of concentrated growth factor and blood clot as scaffolds in regenerative endodontic procedures: A retrospective study

The study aims to investigate and compare the success rate of concentrated growth factor (CGF) and blood clot (BC) as scaffolds in regenerative endodontic procedures (REPs). Immature permanent necrotic teeth treated by REPs with at least a 6-month follow-up were included. These teeth were divided into the CGF (53 teeth) and BC (68 teeth) groups. Treatment outcomes were assessed using a combined clinical and radiographic scoring system. The total success rate was 91.74% over a mean follow-up period of 23.15 months. There was no significant difference between the CGF group (86.79%) and BC group (95.59%). The success rate of traumatic teeth (84.31%) was significantly lower than that of teeth with developmental dental anomalies (98.39%) (p < 0.05). CGF may be a suitable alternative scaffold in REPs when adequate bleeding cannot be achieved. Moreover, compared to developmental dental anomalies, traumatic teeth treated by REPs may be more vulnerable to failure.

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

AIM

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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

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.

Biomaterial scaffolds for clinical procedures in endodontic regeneration

Regenerative endodontic procedures have been rapidly evolving over the past two decades and are employed extensively in clinical endodontics. These procedures have been perceived as valuable adjuvants to conventional strategies in the treatment of necrotic immature permanent teeth that were deemed to have poor prognosis. As a component biological triad of tissue engineering (i.e., stem cells, growth factors and scaffolds), biomaterial scaffolds have demonstrated clinical potential as an armamentarium in regenerative endodontic procedures and achieved remarkable advancements. The aim of the present review is to provide a broad overview of biomaterials employed for scaffolding in regenerative endodontics. The favorable properties and limitations of biomaterials organized in naturally derived, host-derived and synthetic material categories were discussed. Preclinical and clinical studies published over the past five years on the performance of biomaterial scaffolds, as well as current challenges and future perspectives for the application of biomaterials for scaffolding and clinical evaluation of biomaterial scaffolds in regenerative endodontic procedures were addressed in depth.

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Overview of biomaterials for scaffolding in regenerative endodontics are presented.

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Findings of preclinical and clinical studies on the performance of biomaterial scaffolds are summarized.

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Challenges and future prospects in biomaterial scaffolds are discussed.

A critical analysis of clinical research methods to study regenerative endodontics

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

Do intracanal medications used in regenerative endodontics affect the bond strength of powder-to-liquid and ready-to-use cervical sealing materials?

Aim:

This study evaluated the effect of four intracanal medications commonly used in regenerative endodontic procedures on the bond strength of four calcium silicate-based materials, in which two are powder-to-liquid products (MTA and MTA-HP) and the other are ready-to-use materials (EndoSequence Root Repair Material Fast Set Putty [ERRM] and Bioceramic Repair [BIO-C Repair]).

Methods:

Ten bovine central incisors were selected and 4 slices (1.0 ± 0.1 mm) were prepared from each root. Next, four 0.8-mm wide holes were drilled in each slice and specimens were filled with one of the following intracanal medications: triple antibiotic paste, double antibiotic paste, calcium hydroxide with distilled water, and calcium hydroxide with 2% chlorhexidine gel. After 21 days, holes were filled with one of the materials: MTA, MTA-HP, ERRM, or BIO-C Repair. After storage, push-out test and failure analysis were performed. Data were submitted to analysis of variance in a 4 × 4 factorial scheme. Tukey's test was used for multiple comparisons.

Results:

The use of different interappointment dressings did not influence the results (P > 0.05). ERRM and BIO-C Repair presented significantly higher values than MTA and MTA-HP (P < 0.0001). Specimens showed a 100% occurrence of adhesive failures.

Conclusion:

The use of different intracanal medications presented similar impact on bond strength of calcium silicate-based materials. Ready-to-use ERRM and BIO-C Repair materials presented the best push-out values to dentine, whereas powder-to-liquid MTA and MTA-HP cements showed the lowest results.