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

Mahidol Study 2: Treatment Outcomes and Prognostic Factors of Regenerative Endodontic Procedures in Immature Permanent Teeth

INTRODUCTION

Studies on the clinical outcomes and prognostic factors of regenerative endodontic procedures (REPs) in a large population and long-term recall period have been limited. Therefore, the aims of this study were to evaluate treatment outcomes and prognostic factors of REPs.

METHODS

Immature permanent teeth treated with REPs with a minimum one-year follow-up period were included. Treatment outcomes (functional retention, healed rate, root development and sensibility test response) and any prognostic factors were analyzed with multivariable Cox regression, linear regression, and risk-ratio regression.

RESULTS

One-hundred-twenty REPs teeth with a mean 41.7-month recall period were included with a functional retention rate of 97.5%. The healed, healing and diseased rates of REPs were 80%, 9.2%, and 10.8%, respectively. Significant prognostic factors for healed were age (<12 years old) and root development stage (stages 4 and 5). Changes in the apical diameter, root length, root width, and radiographic root area after REPs were 56.8%, 8.3%, 23.2%, and 21.7%, respectively. A significant prognostic factor for continued root development was etiology of pulpal disease (from caries or dens evaginatus). The sensibility test response rate was 41.7% with significant positive factors of EDTA irrigation and capping material level below the cemento-enamel junction.

CONCLUSION

REPs demonstrated high functional retention and healed rates. Patients <12 years old presented a higher healed rate and continued root development (excluding root length). Dental caries or anomalies had higher continued root development compared with dental trauma. The sensibility test response was related to EDTA irrigation and low-level capping material.

Effect of supplementary sodium hypochlorite agitation techniques on an ex vivo oral multispecies biofilm during passive disinfection of simulated immature roots

AIM

To compare the effect of different sodium hypochlorite (NaOCl) agitation techniques on an ex vivo oral multispecies biofilm during passive disinfection of simulated immature roots.

METHODOLOGY

Extracted human teeth were prepared to simulate immature roots. They were infected with a dental plaque-derived multispecies biofilm and cultured for 14 days. The roots were randomly designated into four groups: (1) negative control (PBS), (2) 1.5% NaOCl (CNI), (3) CNI + Ultrasonic activation (UA), (4) CNI + EasyClean agitation (ECA), (5) CNI + XP-endo finisher agitation (XPF), and (6) positive control (6% NaOCl). Biofilm samples were collected from the root canals and used to determine the number of viable cells (colony-forming units), scanning electron microscopy, and 16S rRNA gene sequencing. The mean colony-forming units per mL (CFU/mL) were analysed using One-way anova. 16S rRNA sequencing data were analysed for alpha (observed OTUs, Shannon index, and Chao1) and beta diversity (Bray-Curtis dissimilarities). The LEfSe analysis was used to determine the effect of treatment procedures on the abundance of root canal microbiota. The significance was set at .05.

RESULTS

PBS and CNI samples had significantly higher CFU/mL counts than UA, ECA, XPF, and 6% NaOCl samples (p < .05). The pre-treatment, PBS, and CNI groups had significantly greater alpha diversity than the UA, ECA, XPF, and 6% NaOCl groups (p < .05). NaOCl agitation groups and the 6% NaOCl group achieved a more pronounced reduction in bacteria from the genera Fusobacterium, Actinomyces, Porphyromonas, and Capnocytophaga.

CONCLUSIONS

The effectiveness of passive disinfection protocols was enhanced by NaOCl agitation techniques, suggesting that this supplementary method can improve the outcome of revitalization procedures.

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.

Microbiological assessment of success and failure in pulp revitalization: a randomized clinical trial using calcium hydroxide and chlorhexidine gluconate in traumatized immature necrotic teeth

Aim

To compare differences in the disinfection efficacy of calcium hydroxide (CH) and chlorhexidine gluconate (CHD) dressings in pulp revitalization (PR) of traumatized immature necrotic teeth; to investigate the microflora in successful/failed PR and whether bacterial persistence influences the outcomes of PR.

Methods

Microbiological assessment of the average bacterial load (CFU/sample) and bacterial diversity (taxa/sample) was performed on 41 teeth at three timepoints (S2-before, S3-after debridement and S5- after root canal dressing).

Results

The primary microflora was more diverse in successful cases than in failed. Decreases in CFU/sample and taxa/sample occurred S2 - S3, though new increases occurred at S5 in the CHD subgroup (successful and failed) and CFU/sample in the CH subgroup (failed). At S5, the successful cases showed more bacterial decreases. No specific species was associated with the outcomes with no statistical differences between the disinfection efficacy.

Conclusions

There were no statistical differences in CH and CHD efficacy. At S5, microflora persisted in both successful and failed outcomes, but the abundance and diversity increased significantly only in the failed cases. The successful outcomes presented higher diversity and higher decreases of the primary microflora at S5 than the failed outcomes. The abundance and diversity increased significantly at S5 only in failed cases.

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.

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.

Effect of Intracanal Scaffolds on the Success Outcomes of Regenerative Endodontic Therapy - A Systematic Review and Network Meta-analysis

INTRODUCTION

The scaffolds used in regenerative endodontic therapy (RET) provide structural support for cells so that they can adhere to the scaffolds and also are crucial for cellular proliferation and differentiation. The objective of this network meta-analysis was to compare effects of different intracanal scaffolds on success outcomes of RET.

METHODS

PubMed/Medline, EMBASE, Cochrane, CINAHL, Scopus, and Web of Science databases were searched. Studies evaluating and/or comparing clinical and/or radiographic success of RET using different scaffolds with a minimum of 12 months follow-up were included. The Cochrane Collaboration risk of bias (ROB) tool and appropriate tools from Joanna Briggs Institute were used for the assessment of ROB. A network meta-analysis was performed to compare the primary outcome (clinical success) and other success outcomes (root maturation, and pulpal sensibility) using different scaffolds.

RESULTS

Twenty-seven studies fulfilled the desired inclusion criteria of which 25 had a low ROB whereas 2 had a moderate ROB. Clinical success of RET using platelet-rich plasma (PRP), blood clot (BC), and platelet-rich fibrin (PRF) scaffolds ranged between 91.66%-100%, 84.61%-100%, and 77%-100% respectively. The different scaffolds did not show any statistically significant difference in clinical success (PRF vs BC [P = 1.000], PRP vs BC [P = 1.000], and PRF vs PRP [P = .999]), apical root closure (PRF vs BC [P = 1.000], PRP vs BC [P = .835], PRF vs PRP [P = .956]), and pulp sensibility (PRF vs BC [P = .980], PRP versus BC [P = .520], and PRF vs PRP [P = .990]).

CONCLUSION

The intracanal scaffolds used during RET did not result in significant differences in regard to clinical success, root maturation, and pulpal sensibility.

Antimicrobial potential of new diclofenac hydrogels for disinfection in regenerative endodontics: An in vitro and ex vivo study

AIM

There is a need to explore new alternatives for root canal disinfection in regenerative endodontics, since the current strategies are far from ideal. Currently, the potential use of diclofenac (DC) is being investigated for controlling root canal infections. The objective was to evaluate the antimicrobial efficacy of novel DC-based hydrogels (DCHs) against polymicrobial biofilms grown in radicular dentine and root canals and to compare results with triantibiotic (TAH) and diantibiotic (DAH) hydrogels, and calcium hydroxide (Ca[OH]₂ ).

METHODOLOGY

The in vitro antimicrobial activity of intracanal medicaments was evaluated against 3-week-old polymicrobial root canal biofilms grown on human radicular dentine. Dentine samples were obtained and randomly divided into the study groups (n = 4/group): (1) 1 mg/ml TAH; (2) 1 mg/ml DAH; (3) 5% diclofenac (DCH); (4) 2.5% DCH; (5) 1.25% DCH; (6) 1 mg/ml DAH + 5% DCH; (7) Ca(OH)₂ paste; (8) positive control. The microbial viability, in terms of percentage of intact cell membranes, was assessed after 7 days by confocal scanning laser microscopy (CSLM). The ex vivo efficacy of intracanal medications was evaluated in root canals infected with a polymicrobial suspension. Intracanal microbiological samples at baseline (S1) and 7 days post-treatment (S2) were taken; microbial quantification and cell viability were assessed by quantitative polymerase chain reaction (qPCR) and flow cytometry (FC). The mean Log₁₀ of bacterial DNA copies in root canal samples before (S1) and the Log₁₀ reduction of DNA copies S1-S2 in qPCR were recorded. The absolute value of total cells stained, and the percentage reduction of intact membrane cells after treatment (S1-S2), were analysed by FC. Global comparison was done using the Kruskal-Wallis test, whilst the Mann-Whitney U test was used for pair-by-pair comparison.

RESULTS

Confocal scanning laser microscopy analysis indicated that the greatest effectiveness was obtained with 5% DCH, showing significant differences with respect to the other groups (p < .001). In root canals, the highest Log₁₀ DNA reduction S1-S2 was obtained with 5% DCH and TAH, with no differences between them. The results of FC showed that only 5% DCH proved significantly superior to the other treatments.

CONCLUSIONS

Sodium DC hydrogels demonstrate antimicrobial efficacy against endodontic biofilms.

Microbial identification from traumatized immature permanent teeth with periapical lesions using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

BACKGROUND

This study aims at identifying the microbiota in traumatized immature permanent teeth with periapical lesions using Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).

METHODS

The study included 16 immature maxillary central incisors with periapical lesions in 13 patients. Field decontamination and negative control samples were performed before and after access cavity preparation. Root canal samples were taken using sterile stainless-steel hand files following field decontamination. In-office inoculation and pure sub-cultures were performed. Bacterial isolates were prepared for MALDI-TOF MS (Bruker, Billerica, MA USA) analysis using the formic acid extraction method. A comparison of the prevalence of isolated microorganisms was done using a one-sample chi-square test. Comparisons between identified microbial species with the, cone beam computed tomography periapical index (CBCT PAI) scores and lesion volume were also conducted. The Chi-square test was applied to investigate the association between the categorical variables .

RESULTS

Out of the forty isolates recovered from the 16 traumatized teeth included in the present study with the mean patients' age of 10.93 ± 1.77, 37 isolates were reliably identified by MALDI-TOF MS. Twelve teeth (62.5%) were polymicrobial. The recovered bacteria belonged to five phyla, 15 genera and 25 species. Firmicutes were the predominant phylum (P < 0.001) over Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria. Gram positive bacteria were significantly more prevalent than Gram negative (p = 0.03). Facultative anaerobes were the most prevalent (P < 0.001) compared to the obligate anaerobes and the obligate aerobes. The latter were the least prevalent. Statistically, significant differences existed in the comparison between CBCT PAI scores according to bacterial gram staining.

CONCLUSION

Traumatized immature permanent teeth with periapical lesions showed a significant predominance of Gram-positive facultative anaerobes. MALDI-TOF MS provided accurate identification of numerous viable endodontic microbes.

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.

Antibiofilm Activity of LL-37 Peptide and D-Amino Acids Associated with Antibiotics Used in Regenerative Endodontics on an Ex Vivo Multispecies Biofilm Model

The antimicrobial peptide LL-37 and D-amino acids (D-AAs) have been proposed as antibiofilm agents. Therefore, this study aimed to test the antimicrobial effect of antibiofilm agents associated with antibiotics used in regenerative endodontic procedures (the triple antibiotic paste—TAP: ciprofloxacin + metronidazole + minocycline). An endodontic-like biofilm model grown on bovine dentin discs was used in this study. After 21-day growth, the biofilms were treated with 1 mg/mL TAP, 10 μM LL-37, an association of LL-37 + TAP, 40 mM D-AAs solution, an association of D-AAs + TAP, and phosphate-buffered saline (negative control). Colony forming unit (CFU) data were analyzed by two-way ANOVA and Tukey’s multiple comparison test (p < 0.05). LL-37 + TAP showed the best antibacterial activity (7-log10 CFU/mL ± 0.5), reaching a 1 log reduction of cells in relation to the negative control (8-log10 CFU/mL ± 0.7) (p < 0.05). In turn, no significant reduction in bacterial cells was observed with TAP, LL-37, D-AAs, and D-AAs + TAP compared to the negative control. In conclusion, the combination of antibiotics and LL-37 peptide showed mild antibacterial activity, while the combination of antibiotics and D-AAs showed no activity against complex biofilms.

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.

Photocrosslinkable methacrylated gelatin hydrogel as a cell-friendly injectable delivery system for chlorhexidine in regenerative endodontics

OBJECTIVES

This work sought to formulate photocrosslinkable chlorhexidine (CHX)-laden methacrylated gelatin (CHX/GelMA) hydrogels with broad spectrum of action against endodontic pathogens as a clinically viable cell-friendly disinfection therapy prior to regenerative endodontics procedures.

METHODS

CHX/GelMA hydrogel formulations were successfully synthesized using CHX concentrations between 0.12 % and 5 % w/v. Hydrogel microstructure was evaluated by scanning electron microscopy (SEM). Swelling and enzymatic degradation were assessed to determine microenvironmental effects. Compression test was performed to investigate the influence of CHX incorporation on the hydrogels' biomechanics. The antimicrobial and anti-biofilm potential of the formulated hydrogels were assessed using agar diffusion assays and a microcosms biofilm model, respectively. The cytocompatibility was evaluated by exposing stem cells from human exfoliated deciduous teeth (SHEDs) to hydrogel extracts (i.e., leachable byproducts obtained from overtime hydrogel incubation in phosphate buffer saline). The data were analyzed using One- and Two-way ANOVA and Tukey's test (α = 0.05).

RESULTS

CHX/GelMA hydrogels were effectively prepared. NMR spectroscopy confirmed the incorporation of CHX into GelMA. The addition of CHX did not change the micromorphology (pore size) nor the swelling profile (p > 0.05). CHX incorporation reduced the degradation rate of the hydrogels (p < 0.001); whereas, it contributed to increased compressive modulus (p < 0.05). Regarding the antimicrobial properties, the incorporation of CHX showed a statistically significant decrease in the number of bacteria colonies at 0.12 % and 0.5 % concentration (p < 0.001) and completely inhibited the growth of biofilm at concentration levels 1 %, 2 %, and 5 %. Meanwhile, the addition of CHX, regardless of the concentration, did not lead to cell toxicity, as cell viability values were above 70 %.

SIGNIFICANCE

The addition of CHX into GelMA showed significant antimicrobial action against the pathogens tested, even at low concentrations, with the potential to be used as a cell-friendly injectable drug delivery system for root canal disinfection prior to regenerative endodontics.

Microbiome Changes During Regenerative Endodontic Treatment Using Different Methods of Disinfection

INTRODUCTION

The purpose of this study was to characterize qualitatively and quantitatively the changes in the endodontic microbiome, in teeth with necrotic pulp, open apexes and apical periodontitis, with three antimicrobial protocols, undertaken in a multicenter clinical trial.

METHODS

Microbiological samples were collected from 116 RET teeth, and 97 qualified for inclusion. The teeth were randomly divided into three treatment groups: apexification (APEX), regeneration (REGEN) and revascularization (REVASC), all in two appointments. The group variables in the first appointment irrigants, and second appointment irrigants and medicaments were as follows: APEX: 5.25-6% NaOCl, 5.25-6% NaOCl + 17% EDTA and calcium hydroxide; REGEN: 1.25% NaOCl, 17% EDTA and 0.1 mg/mL triple antibiotic paste (TAP); and REVASC 5.25% NaOCl, saline and 1g/mL TAP, respectively. Sampling was done upon access (S0), after irrigation in the first appointment (S1), and after using medication and irrigation in the second appointment (S2).

RESULTS

Quantitative PCR analysis of the 16S rRNA gene showed significant reduction in bacterial load from S0 to S2 in all groups; however, the APEX and REVASC groups had significantly less residual DNA than the REGEN group (p=0.0045). The relative abundance of Bacteroidetes, Fusobacteria, Spirochaetes and Synergistetes were reduced with the treatment rendered. However, relative abundance of Firmicutes and Actinobacteria was not changed, and that of Proteobacteria increased. LEfSe analysis showed that reduction in bacterial taxa was more in REVASC than APEX which in turn was more than in REGEN.

CONCLUSION

Enhanced antimicrobial protocols lead to better reduction in quantitative and qualitative parameters of the endodontic microflora.

Evaluation of the Antimicrobial Effect of Pre-Synthesized Novel Antibiotic Electrospun Nanofibers as an Intracanal Delivery Strategy for Regenerative Endodontics: A Randomized Clinical Trial

AIM: The aim of this study is to evaluate the antimicrobial effect of pre-synthesized novel antibiotic loaded electrospun nanofibers and compare it with conventional triple antibiotic paste when used in patients with immature necrotic teeth. METHODS: Antibiotic loaded nanofibers were fabricated by electrospinning. Thirty-four patients with immature necrotic teeth were included in the study. In the first visit, access cavity preparation was performed to obtain the first bacteriological sample (S1). The canals were thoroughly irrigated using sodium hypochlorite 1.5% and a second sampling was performed (S2). Patients were randomly divided into two groups according to the intracanal medicament used: Modified triple antibiotic paste (MTAP) loaded electrospun nanofibers or MTAP paste. At the second appointment, the third samples (S3) were taken. The intracanal bacterial count was determined using the spread plate culture technique. Scanning electron microscopy (SEM) was used to examine the morphology of the fabricated MTAP loaded electrospun nanofibers. RESULTS: Both MTAP nanofibers and MTAP paste resulted in significant reduction of bacterial count after the irrigation step. MTAP nanofibers resulted in significantly higher percent reduction of bacterial count (p < 0.05). CONCLUSIONS: It was concluded that electrospinning technology can be used to fabricate antibiotic containing nanofibers which can results in enhanced disinfection in regenerative endodontic procedures.

Is the quality of root canal filling obtained by cone-beam computed tomography associated with periapical lesions? A systematic review and meta-analysis

AIM

To evaluate the influence of root canal filling quality on periapical lesion status using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

The bibliographic search was conducted in electronic databases of PubMed, Embase, Scopus, and Web of Science without restrictions related to the year of publication and language. Inclusion criteria were prospective or retrospective cohort studies that followed periapical pathosis for, at least, 1 year. Three reviewers independently evaluated the eligibility for inclusion, extracted data, and assessed the risk of bias. The quality of the studies was based on the Newcastle-Ottawa Scale. This meta-analysis was performed to evaluate the quality of treatment by the homogeneity and apical extension of the filling.

RESULTS

Of the 1179 studies initially recovered, six cohort studies were included, out of which four were considered with a low risk of bias. The results showed that the absence of gaps in the filling reduced the chance of unhealed periapical lesions by 2.39 times (RR = 2.39; 95% CI: 1.62-3.53; p < 0.00001; I² = 55%). An apical filling extension of 0-2 mm below the apex also contributed significantly to the absence of unhealed periapical lesions (RR = 1.49; 95% CI: 1.15-1.94; p = 0.003; I² = 2%).

CONCLUSION

The homogeneity and apical extension of the filling influenced the presence of unhealed periapical lesions in endodontically treated teeth evaluated using CBCT.

CLINICAL RELEVANCE

Apical extension of the filling ranging between 0 and 2 mm short of the apical foramen and the homogeneity of the filling without gaps are directly related to the success rate of root canal treatment.

"Meta-analysis of regenerative endodontics outcomes with antibiotics pastes and calcium hydroxide. The apex of the iceberg"

PORPOSE

The aim of this study was to evaluate, through a meta-analysis, the predictability of Regenerative Endodontic therapies with antibiotic pastes and calcium hydroxide [Ca(OH)2], related to four variables as follows: root dentin wall thickening, apical closure, apical repair and root lengthening.

METHODS

Literature electronic searches were performed in Pubmed - MEDLINE, Scopus and Lilacs-BVS platforms using appropriate search terms, Mesh (Medical Subject Headings), DeCS (Health Sciences Descriptors) and Boolean operators comprising articles published between 2009 and 2020. Thirty-two original indexed papers were included making a total of 758 regenerative endodontic procedures. A descriptive meta-analysis was performed.

RESULTS

Dentin wall thickening was present in 66% (CI95: 58%-73%) of the cases treated with antibiotic paste, while when Ca(OH)2 was used, a percentage of 53% (CI95: 26%-78%), was obtained. When antibiotic paste was used, apical closure was found in the 66% (CI95: 58%-73%) of the regenerative endodontic procedures, while when Ca(OH)2 was used, 88% (CI95: 80%-93%) of the cases were found to reach apical closure. Root lengthening and apical repair were found satisfactory for both disinfection protocols.

CONCLUSIONS

There could be differences between the two treatments since a higher percentage of root dentin wall thickening was found when using antibiotic pastes, while a higher percentage of apical closure was found when calcium hydroxide was used. Development of more clinical studies would be necessary in order to confirm the observed differences. The proposed approach could provide a useful contribution for endodontists when planning regenerative endodontic procedures, so as to guide decision-making to the best elective treatment and to select the appropriate disinfection method in accordance with preoperative radiographic diagnosis of root development stage, then increasing the predictability of regenerative endodontic treatment and reducing potential risk of root fractures.

Antibacterial Effect of Sodium Hypochlorite and EDTA in Combination with High-Purity Nisin on an Endodontic-like Biofilm Model

Antimicrobial peptides have been proposed as antibiofilm agents. Therefore, we evaluated the effect of endodontic irrigants combined or not with the antimicrobial peptide nisin against an endodontic biofilm model composed of eleven bacterial species. Biofilms were grown on hydroxyapatite discs for 3, 15 and 21 days and treated with 1.5% sodium hypochlorite (NaOCl) or 17% EDTA followed by high-purity nisin (nisin ZP) or saline for 5 min each. Differences between groups were tested by two-way ANOVA and Tukey’s multiple comparisons test (p < 0.05). Treatment with 1.5% NaOCl completely eliminated 3-d and 15-d biofilms but did not eradicate 21-d biofilms. Treatment with 1.5% NaOCl and 17% EDTA was equally effective against 21-d biofilms, showing 5-log and 4-log cell reduction, respectively, compared to the untreated control (9 log₁₀, p < 0.05). No significant difference was found between 1.5% NaOCl + nisin ZP and 1.5% NaOCl in 21-d biofilms (p > 0.05). Likewise, no significant difference was found between 17% EDTA + nisin ZP and 17% EDTA treatments (p > 0.05). In conclusion, 1.5% NaOCl or 17% EDTA were effective strategies to combat mature biofilms. The additional use of nisin did not improve the activity of conventional irrigants against multispecies biofilms.

Clinical and Radiographic Outcomes of Regenerative Endodontic Procedures in Traumatized Immature Permanent Teeth: Interappointment Dressing or Single-Visit?

INTRODUCTION

More data are needed before affirming that single-visit approaches are effective and safe for regenerative endodontic procedures (REPs). This study compared clinical and radiographic outcomes of REPs between interappointment dressing or single-visit protocols.

METHODS

Twenty young patients presenting traumatized immature teeth with pulp necrosis were divided into 2 groups. Teeth were submitted to 6% sodium hypochlorite and 2% chlorhexidine irrigation and to 17% EDTA use before blood clot induction. In the interappointment dressing group (n = 11), calcium hydroxide was used with 2% chlorhexidine gel for 21 days before scaffold induction. In the single-visit group (n = 9), the scaffold was induced during the only appointment. Patients were followed up for 24 months. Primary, secondary, and tertiary outcomes were assessed by 3 independent evaluators. Preoperative and follow-up radiographs were assessed for quantitative measurements of the apical diameter, root width, root length, and cervical barrier placement and compared between groups using the t test or Mann-Whitney U test. Categoric variables were assessed with the G test and the Fisher exact test and continuous variables with the Mann-Whitney U test. Statistical significance was set at 5%.

RESULTS

One tooth showed persistence of infection. No difference was observed in cervical barrier placement (P > .05); between groups regarding primary, secondary, and tertiary outcomes (P > .05); and in parameters of quantitative radiographic outcomes (P > .05).

CONCLUSIONS

Completing REPs with an interappointment dressing or a single-visit protocol presented similar clinical and radiographic outcomes. A single-visit protocol of REPs using 6% sodium hypochlorite, 2% chlorhexidine, and 17% EDTA permitted satisfactory outcomes in necrotic immature permanent teeth.

Effectiveness of Autologous Platelet Concentrates in Management of Young Immature Necrotic Permanent Teeth-A Systematic Review and Meta-Analysis

The use of autologous platelet concentrates (APCs) in regenerative endodontic procedures is inconsistent and unclear. The aim of this meta-analysis was to evaluate the effectiveness of autologous platelet concentrates compared to traditional blood-clot regeneration for the management of young, immature, necrotic, permanent teeth. The digital databases MEDLINE, SCOPUS, CENTRAL, Web of Science, and EMBASE were searched to identify ten randomized clinical trials. The outcomes at postoperative follow-up, such as dentinal wall thickness (DWT), increase in root length (RL), calcific barrier formation (CB), apical closure (AC), vitality response (VR), and success rate (SR), were subjected to both qualitative synthesis and quantitative meta-analysis. The meta-analysis showed that APCs significantly improved apical closure (risk ratio (RR) = 1.17; 95% CI: 1.01, 1.37; p = 0.04) and response to vitality pulp tests (RR = 1.61; 95% CI: 1.03, 2.52; p = 0.04), whereas no significant effect was observed on root lengthening, dentin wall thickness, or success rate of immature, necrotic teeth treated with regenerative endodontics. APCs could be beneficial when treating young, immature, necrotic, permanent teeth regarding better apical closure and improved response to vitality tests.