Regenerative Endodontic Procedure of Immature Permanent Teeth with Leukocyte and Platelet-rich Fibrin: A Multicenter Controlled Clinical Trial

Biological properties of stem cells from the apical papilla exposed to lipopolysaccharides: An in vitro study

OBJECTIVE

The aim of this study was to analyze the effect of lipopolysaccharides (LPS) on the biological properties of stem cells from the apical papilla (SCAPs), such as viability, adhesion to dentin, odontoblast-like differentiation, mineralization, and release of immunomodulatory cytokines.

DESIGN

SCAPs were isolated from immature teeth of three donors (10 to 15 years old) and cultured in mineralizing media with or without 1 μg/mL lipopolysaccharide (LPS). Cells were seeded and cultured under standardized conditions; viability was assessed by MTT assay on days 1, 3, 5, and 7; adhesion to dentin was analyzed using an environmental scanning electron microscope after 2 days; the expression of odontogenic and mineralization genes (DSPP, DMP-1, OCN, Col1A1) was evaluated through qPCR after 14 days, mineralization was evaluated with alizarin red staining after 21 days; and the release of immunomodulatory cytokines (IL-6 and IL-10) was measured by ELISA after 1 and 7 days. The Kruskal-Wallis test was performed to detect the effect of LPS on SCAPs, followed by the Dunn-Sidak test.

RESULTS

LPS presence in the culture media affected SCAPs viability on day 5 and increased IL-6 secretion by day 7, however, SCAPs retained the adhesion to dentin and mineralization capacities, as well as the differentiation capacity into a mineralizing phenotype.

CONCLUSION

In conclusion, within the limitations of this in vitro study, and under the inflammatory microenvironment simulated in this study, stem cells from the apical papilla were found with retained adhesion capacity to dentin, differentiation into a mineralizing phenotype, mineralization, and release of IL-10.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

Revitalization procedures primarily aim to eliminate clinical symptoms and heal periapical lesions.

OBJECTIVES

The objective of the study was to elucidate the effectiveness of revitalization in treating apical periodontitis in necrotic mature and immature permanent teeth based on the following PICO question: In patients with permanent immature or mature teeth and pulp necrosis with or without signs of apical periodontitis (P) what is the effectiveness of revitalization (I) in comparison with calcium hydroxide apexification, apical plug and root canal treatment (C) in terms of tooth survival, pain, tenderness, swelling, need for medication (analgesics and antibiotics), radiographic evidence of reduction of apical lesion size, radiographic evidence of normal periodontal ligament space, radiographic evidence of increased root thickness and length (not for mature teeth), tooth function (fracture and restoration longevity), need for further intervention, adverse effects (including exacerbation, restoration integrity, allergy and discolouration), oral health-related quality of life (OHRQoL), presence of sinus tract and response to sensibility testing (O). (T) = Defined as a minimum of 1 year and maximum of as long as possible for all outcome measures, except 'pain, tenderness, swelling, need for medication (analgesics)', which is a minimum of 7 days and maximum of 3 months and OHRQoL which is minimum of 6 months and a maximum of as long as possible.

METHODS

Three databases (PubMed, Embase and Cochrane Library) were searched for human, experimental and observational studies in English, complemented with hand search, until 31/10/2021. Studies recruiting teeth with pulp necrosis (with/without apical periodontitis), with minimum 10 teeth/arm at the end of the study and with a follow-up of at least 1 year, were included. Records without an abstract and a full text were excluded. The qualitative analysis of the included (non-) randomized controlled clinical trials was performed with the Revised Cochrane risk-of-bias tools (RoB 2 and ROBINS-I). Meta-analysis for survival and success (including a subgroup analysis for mature/immature permanent teeth) was performed using the Mantel-Haenszel method. The certainty of evidence was assessed using GRADE (Grades of Recommendation, Assessment, Development and Evaluation).

RESULTS

From the 365 identified records, five met the inclusion criteria. The 12 months survival rate was 100% for all (im)mature permanent teeth in all groups (3 studies). The success rate at 12 months was 100% for immature permanent teeth for I and C (1 study), however, reduced to 92% and 80% for mature teeth in I and C respectively (1 study, p > .05). The risk of bias for the most critical outcome (survival) was high for two studies and low for one. For the critical outcome success, all assessed studies were highly biased. Meta-analyses provided pooled relative risk with no statistically significant difference between I and C for both survival (RR = 1.00, 95%CI = 0.96-1.04, p = 1.00) and success (RR = 1.06; 95%CI = 0.83-1.35, p = .66). The evidence level for survival was kept 'low' and for success was downgraded to 'very low' due to inconsistency and imprecision.

DISCUSSION

The survival and success rates were favourable in all included studies and for all groups; however, these outcomes are not reliable due to the low certainty level. Clinically, the most reported adverse event was tooth discolouration, hence the application of bismuth oxide containing calcium silicate cements should be avoided in revitalization. Radiographically, caution is needed when assessing periapical bone healing and further root development with periapical radiographs, due to multifactorial inaccuracies of this imaging technique. Methodological and assessment concerns need to be addressed in future clinical trials. Long-term results are necessary for studies reporting revitalization of mature permanent teeth, as they seem to be experimental so far.

CONCLUSIONS

No robust evidence was discovered to support that revitalization is effective to treat apical periodontitis in (im)mature permanent teeth. The success and survival rates of revitalized and fully pulpectomized (im)mature permanent teeth did not differ significantly.

REGISTRATION

Prospero: CRD42021262466.

Review of guidance for the selection of regenerative endodontics, apexogenesis, apexification, pulpotomy, and other endodontic treatments for immature permanent teeth

This review guidance is a work in progress because the limitations of regenerative endodontics are still being discovered. The endodontic treatments for immature permanent teeth with a necrotic pulp can vary considerably among endodontic practitioners. Whereas, regenerative endodontic treatments are growing in popularity and are creating ever more complex treatment protocols, involving revascularization and/or autologous platelet-rich plasma and scaffolds to elicit host stem cell de novo tissue formation to reestablish the vitality of immature teeth for the purpose of continuing root maturation. Despite much evolving controversy about their potential benefits, risks, prognosis, and contraindications, this review is aimed to discuss how to ensure that regenerative endodontic treatments are successful, by strictly adhering to case selection criteria, and following precise steps to accomplish and monitor the success of the treatment. A review of the endodontic literature was performed, together with practical observations of the problems and outcomes of performing regenerative endodontic treatments. Traditionally, apexification has long been the treatment of choice provided to immature teeth with a necrotic pulp. Regenerative endodontics may be provided as an alternative to apexification, if the tooth and patient meet all the case selection criteria, and if there are no contraindications. Regenerative endodontics has the unique potential advantage of being able to continue the root development in immature permanent teeth, thereby potentially saving the teeth for the lifetime of the patient. Whereas, conventional endodontic root canal treatment, Cvek partial pulpotomy, apexogenesis, and apexification, should always be provided when these treatments are more likely to benefit the patient because they can be more successful than regenerative endodontics.

DENTAL PATIENT-REPORTED OUTCOMES IN ENDODONTICS - A NARRATIVE REVIEW

Recently in oral health care settings, the focus of assessing treatment outcomes has shifted from the perspective of the clinician towards that of the patient. Endodontology is a specialty of dentistry concerned with the prevention and treatment of pulp and periapical diseases. Research in endodontology and its associated treatment outcomes have focused mainly on clinician-reported outcomes (CROs) and not dental patient-reported outcomes (dPROs). As a result, there is a need to emphasize the importance and relevance of dPROs to researchers and clinicians. The aim of this review is to present an overview of dPROs and dPROMs within endodontics in an attempt to create a better understanding of the patient experience, highlight the need to place the patient at the center of treatment, enhance patient care and encourage more research into dPROs. The key dPROs following endodontic treatment include pain, tenderness, tooth function, need for further intervention, adverse effects (exacerbation of symptoms, tooth discoloration) and Oral Health-Related Quality of Life. dPROs are important following endodontic treatment because they assist clinicians and patients when they discuss and select the most appropriate management options, help clinicians make decisions on pre-operative assessment, prevention and treatment, and improve the methodology and design of future clinical studies. Clinicians and researchers in endodontology should prioritize patient welfare and undertake routine analyses of dPROs using appropriate and robust measures. Due to the lack of agreement over the reporting and definition of endodontic treatment outcomes, a comprehensive project to define a ``Core Outcome Set for Endodontic Treatment Methods (COSET)'' is currently ongoing. In the future, a new and exclusive assessment tool should be developed to reflect the viewpoints of patients receiving endodontic treatment more accurately.

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

OBJECTIVES

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

DESIGN

Randomised controlled trial.

SETTING

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

METHODS AND INTERVENTION

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

MAIN OUTCOME MEASURE

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

RESULTS

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

CONCLUSIONS

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

TRIAL REGISTRATION NUMBER

ChiCTR-INR-17012169.

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.

A Bibliometric Analysis of Platelet-Rich Fibrin in Dentistry

Platelet-rich fibrin (PRF), a second-generation platelet concentrate, has been widely recognized in numerous studies for its performance of wound healing and regeneration in dentistry. However, bibliometric analysis of PRF in dentistry is still scarce. Thus, this study aimed to conduct and delineate a bibliometric analysis of the application of PRF and its changing trend in dentistry. All papers concerning PRF up to 30 June 2022 were included in the literature search from the Web of Science Core Collection database. These data were then entered into Microsoft Excel, analyzed by the SAS statistical software, and visualized by the VOSviewer software. A total of 562 articles were retrieved following the exclusive criteria. The results demonstrated that the trend of annual publication increased continually (p for trend < 0.01), more notably in the last five years. The majority of the articles were original (58.01%), followed by reviews (17.08%), and case reports (10.14%). The three major study designs were clinical studies (20.11%), randomized controlled trials (17.62%), and review/meta-analysis (17.08%). PRF was most frequently employed in oral surgery (31.14%), periodontal regeneration (22.42%), and implant therapy (18.68%). Turkey (16.19%), India (12.28%) and China (7.12%) were the top 3 countries publishing PRF studies. By comparing the total number of publications, total citation counts and varying counting methods, a combination of numerous counting methods was suggested for use since each counting method yields different results. Taken together, we hope with these informative findings, researchers could focus on the future direction or advancement in PRF, laying a foundation for evidence-based dentistry.

Tissue Characteristics in Endodontic Regeneration: A Systematic Review

The regenerative endodontic procedure (REP) represents a treatment option for immature necrotic teeth with a periapical lesion. Currently, this therapy has a wide field of pre-clinical and clinical applications, but no standardization exists regarding successful criteria. Thus, by analysis of animal and human studies, the aim of this systematic review was to highlight the main characteristics of the tissue generated by REP. A customized search of PubMed, EMBASE, Scopus, and Web of Science databases from January 2000 to January 2022 was conducted. Seventy-five human and forty-nine animal studies were selected. In humans, the evaluation criteria were clinical 2D and 3D radiographic examinations. Most of the studies identified a successful REP with an asymptomatic tooth, apical lesion healing, and increased root thickness and length. In animals, histological and radiological criteria were considered. Newly formed tissues in the canals were fibrous, cementum, or bone-like tissues along the dentine walls depending on the area of the root. REP assured tooth development and viability. However, further studies are needed to identify procedures to successfully reproduce the physiological structure and function of the dentin–pulp complex.

Evaluation of the Effectiveness of Laser-Assisted Bleaching of the Teeth Discolored due to Regenerative Endodontic Treatment

Regenerative endodontic treatments (RETs) as a valuable treatment option to save the immature necrotic teeth, have been reported to be associated with discoloration which is an inevitable unfavorable outcome. The present study aimed to compare three laser-assisted protocols with conventional walking bleaching in terms of bleaching efficacy. Seventy-two human incisor teeth underwent regenerative treatment. A triple antibiotic paste containing minocycline, ciprofloxacin, and metronidazole was used as an intracanal medicament. A human blood clot was applied as a scaffold and capped by a hydraulic calcium silicate-based cement. Ten weeks after the RET procedure, a four-session bleaching course started. Teeth were assigned to four groups: (1) 35% hydrogen peroxide gel, (2) 35% hydrogen peroxide gel + Nd: YAG laser, (3) 35% hydrogen peroxide gel + 980 nm diode laser, and (4) 35% hydrogen peroxide gel + 810 nm diode laser. The color changes (ΔE) were measured before and after bleaching sessions. The data were analyzed using Kruskal-Wallis nonparametric test. The statistical significance level was set at 0.05. Significant discoloration, exceeding the perceptibility threshold (ΔE > 3.7) was observed in all of the samples ten weeks after RET. There was no significant difference between groups in terms of RET-induced discoloration values (p > 0.05). Bleaching either by using 35% hydrogen peroxide or 35% hydrogen peroxide activated by different lasers used in this study resulted in significant tooth whitening (p < 0.05). There was no statistically significant difference among the groups in terms of bleaching efficacy (p > 0.05). Internal bleaching by using 35% hydrogen peroxide is as effective as laser-assisted protocols for correction of crown discoloration in teeth that have undergone RET.

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

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

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.