Apical root canal microbiome associated with primary and posttreatment apical periodontitis: A systematic review.

BACKGROUND: Microorganisms colonizing the apical root canal system are conceivably the ones directly involved with the causation and maintenance of apical periodontitis. OBJECTIVES: This article systematically reviews the reports on the microbiome occurring exclusively at the apical root canal of teeth with primary and posttreatment apical periodontitis. METHODS: The electronic databases PubMed, Embase, Web of Science, Science Direct, and Proquest were searched up to August 2023. Clinical studies using culture and molecular microbiology methods to identify the microbial taxa present exclusively in the apical root canal segment of infected teeth with apical periodontitis were included. Studies were critically assessed using the Joanna Briggs Institute Critical Prevalence Assessment Checklist. RESULTS: From 2277 articles initially detected, 52 were selected for full reading and 21 were eventually included in this review. Of these, molecular methods were used in 19 and culture in 2 studies. Ten studies evaluated primary infections, 8 evaluated posttreatment infections, and 3 included both. Cryopulverization of the apical root specimens was conducted in 11 studies. All studies evaluated the prevalence and diversity of bacteria, and only one also reported on fungi. Overall, the most frequent/abundant bacterial taxa found in the apical canal of primary infections were Pseudoramibacter alactolyticus, Olsenella uli, Fusobacterium species, Streptococcus species, Porphyromonas endodontalis, Prevotella species, Actinomyces species, Parvimonas micra, Treponema denticola, Synergistetes species, and an as-yet uncharacterized taxon. In posttreatment infections, the most prevalent/abundant bacterial taxa included species of Streptococcus, Enterococcus, Fusobacterium, Actinomyces, Pseudoramibacter, Pseudomonas, and Propionibacterium. At the phylum level, Firmicutes was the most represented. The average apical bacterial load ranged from 105 to 106 in primary infections and from 103 to 104 in posttreatment infections. DISCUSSION: Microbial diversity in the apical part of the root canal system was examined encompassing data from both primary and posttreatment infections. Heterogeneity amongst the studies, especially in sample collection and microbial identification methods, is an important limitation that prevented a meta-analysis. CONCLUSIONS: There is a pronounced bacterial diversity in the infected apical canal, with a high interindividual variability. Different microbiome compositions at the species/genus level are observed according to the infection type. REGISTRATION: PROSPERO CRD42021275886.

Postoperative pain in oncological patients subjected to nonsurgical root canal treatment: a prospective case-control study.

OBJECTIVES: The purpose of this prospective study was to evaluate the incidence and intensity of postoperative pain in oncological patients with infected teeth subjected to nonsurgical root canal treatment or retreatment. METHODS: Teeth with apical periodontitis from healthy control patients and oncological patients (n = 70 per group) were root canal treated/retreated and evaluated for the development of postoperative pain. Patients from the two groups were matched for tooth type, gender, clinical manifestation of apical periodontitis, and intervention type. A visual analogue scale (VSA) was used to evaluate the incidence of postoperative pain at 24 h, 72 h, 7d, and 15d after chemomechanical procedures. Data were statistically analyzed for the incidence and intensity of postoperative pain in the two groups. RESULTS: Preoperative pain occurred in 10% of the individuals and in all these cases pain showed a reduction in intensity or was absent after endodontic intervention at 24-h evaluation. The overall incidence of postoperative pain at 24 h was 14% in oncology patients and 30% in controls (p = 0.03). At 72 h, the respective corresponding figures were 4% and 8.5% (p > 0.05). At 7 and 15 days, all patients were asymptomatic, irrespective of the group. CONCLUSIONS: No significant differences in postoperative pain were found between control and oncological patients. The low incidence of postoperative pain observed in both groups supports the routine use of nonsurgical root canal treatment/retreatment as valid options in oncological patients. CLINICAL RELEVANCE: Oncological patients had no increased risk of postoperative pain in comparison with control patients.

Influence of brushing motions on the shaping of oval canals by rotary and reciprocating instruments.

OBJECTIVE: The effects of brushing on shaping with three different instruments were assessed in oval canals. DESIGN: Mandibular incisors were assigned to 6 groups (n = 12/group) according to the system, each one with or without brushing: Reciproc Blue, VDW.Rotate, and Race EVO. Micro-computed tomography was performed before and after preparation. RESULTS: Brushing strokes caused no increase in canal volume, surface area, and structure model index independently of the system (p > 0.05), except for RaCe EVO in the full canal surface area (p < 0.05). Brushing did not increase the prepared areas (p > 0.05), except for Reciproc in the apical canal (p < 0.05). Reciproc with no brushing exhibited less pericervical dentin than with brushing (p < 0.05), while RaCe EVO with brushing resulted in less remaining dentin (p < 0.05). CONCLUSIONS: The brushing motion had no effects on the overall shaping performance of the 3 instruments tested. An exception was the increase in prepared surface area in the apical canal segment when the Reciproc instrument was used with brushing strokes.

Reciproc and Reciproc Blue in the removal of bioceramic and resin-based sealers in retreatment procedures.

OBJECTIVES: To compare the remaining root canal filling material, dentin removal, apical transportation, and apical extrusion of debris after the retreatment of canals filled with bioceramic or resin-based sealers using the Reciproc or Reciproc Blue instruments. MATERIALS AND METHODS: Sixty mandibular molars with severely curved mesial roots were selected. The samples were initially instrumented with Reciproc (R25) and then divided into four experimental groups according to the endodontic sealer and retreatment instrument (n = 15): BC Sealer/Reciproc (BCRC), BC Sealer/Reciproc Blue (BCRB), AH Plus/Reciproc (AHRC), and AH Plus/Reciproc Blue (AHRB). The procedure time was measured, and an Eppendorf tube was used in each root canal to store the debris extrusion. The samples were scanned by micro-CT before and after retreatment. The apical transportation, volume of dentin, and filling material were evaluated. RESULTS: There were no significant differences in the reduction of the volume of obturator material or dentin removal between groups (p > .05). There were also no differences in the amount of extruded material or apical transportation (p > .05). The retreatment time for the AHRC group was significantly lower than that for the other groups (p = .004). CONCLUSIONS: All tested instruments obtained similar efficacy in filling material removal procedures, although no system completely removed the filling material. Retreatment of canals filled with bioceramic BC Sealer may be more time consuming. CLINICAL RELEVANCE: This study reported that Reciproc and Reciproc Blue can be indicated in retreatment of severely curved root canals filled either with bioceramic or resin-based sealers.

The Role of the Dental Surgeon in Controlling the Dissemination of COVID-19: A Literature Review.

As early as December 2019 in the province of Hubei, China, contamination of patients with pneumonia of an unknown etiology occurred. These patients presented with symptoms such as coughing, sore throat, malaise, diarrhea, high fever, and dyspnea. This emerging disease was named COVID-19 due to being part of the group of coronaviruses (CoVs) belonging to the subfamily Orthocoronavirinae, in the Coronaviridae family and in the Nidovirales order. COVID-19 is most commonly transmitted through speech, coughing, sneezing, and salivary sputum. Because dental professionals work closely with the oral cavity, it is imperative that infection prevention controls are strictly adhered to. It is important that the dental profession treats patients while also limiting the possible contamination through the production of aerosol in the dental environment. Furthermore, the dental professional also has a key role in raising awareness and guidance amongst the population concerning COVID-19 related biosafety measures. This literature review aims to inform dental professionals about the COVID-19 pandemic and to present the implications of the virus to the dentist. Dental professionals are considered to be at high risk for contracting SARS-CoV-2.

Occurence of dentinal defects after root canal preparation with R-phase, M-Wire and Gold Wire instruments: a micro-CT analysis.

BACKGROUND: This study aims to evaluate the frequency of dentinal defects after root canal preparation with the ProTaper NEXT, K3XF and WaveOne GOLD systems using microcomputed tomography. METHODS: Sixty permanent mandibular incisors with a single canal were selected. Inspection of the teeth was performed under a stereomicroscope (15x) to observe the presence of pre-existing cracks and fractures lines. Samples were divided into three experimental groups (n = 20): ProTaper NEXT (PTN), K3XF (K3XF) and WaveOne GOLD (WOG). Specimens were scanned through high-resolution microcomputed tomography before and after the preparation of the root canal. Subsequently, all the axial images were examined by two different methods to find possible dentinal defects. Furthermore, an analysis of each millimeter of ten apical millimeters was also performed. The absence or presence of dentinal defects was screened by 3 pre-calibrated blinded examiners. RESULTS: After analysing all 45,720 slices, dentinal defects were observed in 48,33% (22096 slices). PTN, K3XF and WOG groups represented 11,11% (5079 slices), 17,22% (7873 slices) and 20% (n = 9144) of the cross-sectional images, respectively. At 10 apical millimeters (600 slices), 33,33% (200 slices) presented some dentinal defects, representing 7,22% (43 slices), 13,33% (80 slices) and 12,77% (77 slices) of the cross-sectional images in the PTN, K3XF and WOG groups, respectively. All the dentinal defects presented in the postoperative images existed in the images prior to instrumentation. CONCLUSIONS: There was no correlation between the preparation of a root canal using the PTN, K3XF and WOG systems and the formation of new dentinal defects.

Apical Extrusion of Debris Produced during Continuous Rotating and Reciprocating Motion.

This study aimed to analyse and compare apical extrusion of debris in canals instrumented with systems used in reciprocating and continuous motion. Sixty mandibular premolars were randomly divided into 3 groups (n = 20): the Reciproc (REC), WaveOne (WO), and HyFlex CM (HYF) groups. One Eppendorf tube per tooth was weighed in advance on an analytical balance. The root canals were instrumented according to the manufacturer's instructions, and standardised irrigation with 2.5% sodium hypochlorite was performed to a total volume of 9 mL. After instrumentation, the teeth were removed from the Eppendorf tubes and incubated at 37°C for 15 days to evaporate the liquid. The tubes were weighed again, and the difference between the initial and final weight was calculated to determine the weight of the debris. The data were statistically analysed using the Shapiro-Wilk, Wilcoxon, and Mann-Whitney tests (α = 5%). All systems resulted in the apical extrusion of debris. Reciproc produced significantly more debris than WaveOne (p < 0.05), and both systems produced a greater apical extrusion of debris than HyFlex CM (p < 0.001). Cross section and motion influenced the results, despite tip standardization.

Photodynamic therapy in the coadjuvant treatment of Sporothrix schenckii complex.

INTRODUCTION: Sporotrichosis, a zoonosis caused by animal, mainly cat, scratches or bites, is caused by fungi belonging to the Sporothrix complex. Treatment usually consists in antifungal administration, although treatment failure and hepatotoxicity reports have been noted. Alternative sporotrichosis treatment methods, such as antimicrobial photodynamic therapy (aPDT), may, therefore, be indicated. CASE REPORT: In this context, this study followed a 56-year-old male renal transplanted patient displaying disseminated sporotrichosis, presenting erythematous skin lesions with ulcerated backgrounds and hardened consistency on the nose, oral and scalp. The lesions were present for about 2 months and the patient coexisted with cats. Intravenous amphotericin B administration was initiated, and immunosuppression was suspended. Seven aPDT sessions were also performed in 48 h intervals on the oral lesions, employing 0.01% methylene blue gel as the photosensitizing agent. After the 4th aPDT session, the patient was discharged, amphotericin B administration was suspended, and the treatment was continued with itraconazole, without immunosuppression. Red laser was applied to the oral lesions after the 7th aPDT session. Significant lesion improvement was observed after the final aPDT session and complete palate lesion repair was noted after two red laser sessions. CONCLUSION: These findings indicate that aPDT is a valuable strategy as an adjunct sporotrichosis treatment.

Proteins Associated with Persistent Apical Periodontitis: A Scoping Review.

This scoping review aimed to assess immunohistochemical markers associated with the physiopathogenesis of Persistent Apical Periodontitis. The protocol was adapted from the Joanna Briggs Institute Reviewer's Manual (2017) and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for Scoping Reviews. A total of 239 articles were considered potentially eligible, and their full texts read by two reviewers. Six articles were included. The included articles were published between 1999 and 2017. A total of 12 biomarkers were identified, forkhead box P3, cluster of differentiation (CD)3, CD8, CD450, CD68, transforming growth factor alpha, transforming growth factor-beta1, matrix metalloproteinase-9, receptor activator of nuclear factor kappa beta ligand, osteoprotegerin, CD90 and sex-determining region Y-box 2; categorized according to their applicability. Among the biomarkers identified, receptor activator of nuclear factor kappa beta ligand and osteoprotegerinare were related to bone remodeling in apical periodontitis and may also be associated with persistent apical periodontitis.

Effectiveness of supplementary antimicrobial procedures in disinfecting lateral canals as evaluated by a novel ex vivo analytical approach.

This ex vivo study devised an analytical ex vivo method for infection/disinfection of simulated lateral canals located in the middle and apical segments of the root. The antibacterial effects of supplementary approaches were tested in this model. Extracted mandibular premolars had their main root canals enlarged and then two lateral canals (100 µm in diameter) were created in the root, one in the apical and the other in the middle portion. Micro-computed tomography was used for specimen selection and to confirm the quality of the simulated ramifications. The specimens were contaminated with a mixed bacterial culture from subgingival bacterial biofilm added to pure Enterococcus faecalis strain ATCC 29212 grown overnight, using special strategies to facilitate culture medium penetration within the lateral canals. The following procedures were tested for disinfection: NaOCl/passive ultrasonic irrigation (PUI), NaOCl/XP-endo Finisher, ozonated water/continuous ultrasonic irrigation (CUI), and NaOCl/conventional irrigation with 30-G needles (control). Bacteriological samples were taken from the main canal before (S1) and after (S2) each supplementary protocol, and also from each lateral canal after treatment (S3). DNA extracted from the samples was subjected to quantitative real-time polymerase chain reaction. All S1 main canal samples were positive for bacterial presence. Bacterial counts in the main root canal substantially decreased by 99.2% after PUI, 99.1% after ozone/CUI, 99% after XP-endo Finisher, and 96% in the control group (P < 0.01 for all groups). There were no significant differences between groups (P > 0.05). The same was observed when comparing the effects of the supplementary approaches in the apical and middle lateral canals (P > 0.05). Only a few lateral canals showed no detectable bacteria. The method proposed here proved effective for ex vivo infection/disinfection studies. All supplementary approaches induced a substantial bacterial reduction in the main canal, with no significant differences between them. However, in terms of lateral canal disinfection, none of the tested approaches showed significant effects when compared to the control group.

Photodynamic Therapy as an adjunct in the Treatment of Medication-Related Osteonecrosis of the Jaw: A Case Report.

Introduction: Medication-related osteonecrosis of the jaw (MRONJ) corresponds to an adverse effect of the use of drugs such as bisphosphonates and denosumab. This condition is often associated with pain, infection, purulent secretion, paraesthesia, tooth mobility and halitosis, decreasing the patient's quality of life. The management of MRONJ tends to be conservative, through the guidance of oral hygiene, antibiotic therapy and mouthwashes. However, the use of antimicrobial photodynamic therapy (aPDT) has shown promise in the treatment of these injuries. The purpose of this article is to report a case of MRONJ treatment associated with aPDT. Case Report: A 75-year-old patient, with a history of breast cancer and use of intravenous Zoledronic Acid, presented with bilateral MRONJ lesions in tuberosity on the right and left sides. Treatment was conservatively instituted with the use of aPDT as an adjuvant. After 12 aPDT sessions, complete regression of the lesion was observed. However, after two weeks, the presence of a new lesion was noted, this time in the anterior region of the maxilla. The same protocol previously established was followed and after two aPDT sessions, the patient returned with complete lesion regression. Conclusion: The use of aPDT may represent an important adjuvant within a set of clinical protocols in the treatment of MRONJ.

Influence of occlusal reduction on pain after endodontic treatment: a systematic review and meta-analysis.

The purpose of this systematic review was to analyze the influence of occlusal reduction on the postoperative pain levels after endodontic treatment (instrumentation and obturation of the root canal system). This review followed the PRISMA statement and was registered at PROSPERO (CRD42018107918). Two independent reviewers searched the Lilacs, Cochrane Library, PubMed (Medline), Web of Science, Scopus, Scielo, and ScienceDirect for articles published until April 2021. The research question was, "Does occlusal reduction decrease postoperative pain in endodontically treated teeth?". Only randomized clinical trials were included. The RevMan 5 program was used for meta-analysis, calculating the relative risk (RR) and 95% confidence interval (CI) of the dichotomous outcome (presence or absence of pain). The search strategies retrieved 4114 studies. Twelve studies were included for qualitative analysis and nine for quantitative analysis. The meta-analysis results did not reveal a significant difference in the reduction of postoperative pain levels for endodontic instrumentation at 6, 12, 24, 48 h and for endodontic obturation at 6 or 12 h after occlusal reduction. According to the GRADE tool, the analyzed outcome was classified as having a moderate level of certainty. It is concluded that occlusal reduction does not interfere with postoperative pain levels after endodontic treatment.

Micro-CT analysis of dentinal microcracks on root canals filled with a bioceramic sealer and retreated with reciprocating instruments.

This study aimed to analyze the potential occurrence of dentinal defects after the removal of a root canal filling with two different sealers using Reciproc (RC) or Reciproc Blue (RB). The mesial roots of 60 mandibular molars with a Vertucci type IV configuration were selected. The samples were initially instrumented with Reciproc (R25) and then divided into the following four experimental groups according to the endodontic sealer and retreatment instrument (n = 15): BC Sealer/Reciproc (BCRC); BC Sealer/Reciproc Blue (BCRB); AH Plus/Reciproc (AHRC); and AH Plus/Reciproc Blue (AHRB). Then, the samples were scanned under micro-CT after obturation and removal of the filling material. Two analyses were conducted. First, an evaluation was performed on all the axial images, and another analysis evaluated each millimeter of the 10 mm from the apex. Dentinal defects were observed in all the samples. All of the identified defects in the images after filling material removal were present in the corresponding images after obturation. The use of AH Plus and EndoSequence BC Sealer, and filling material removal using RC and RB instruments did not induce dentinal defects.

Effects of Reciproc, ProTaper Next and WaveOne Gold on Root Canal Walls: A Stereomicroscope Analysis.

INTRODUCTION: The aim of this study was to analyse the potential occurrence of dentinal defects after root canal preparation using three engine-driven instruments. METHODS AND MATERIALS: Eighty permanent mandibular incisors were selected. Twenty teeth did not undergo preparation, and the remaining teeth were divided into three groups (n=20): Reciproc (REC), ProTaper Next (PTN) and WaveOne Gold (WOG). The samples were dyed with methylene blue, sectioned perpendicularly to the long axis in 3-, 6- and 9-mm slices and were finally observed under a stereomicroscope (under 25×). The absence/presence of dentinal defects was documented by two blind observers. The data were analysed using Pearson's chi-squared test with a confidence level of 95% (P=0.05). The time to prepare the samples was recorded, and the groups were compared using F-test (ANOVA). RESULTS: The control group did not present any defects, and the differences between the control and experimental groups were statistically significant (P<0.05). WOG, PTN and REC caused microcracks on 60%, 33.33% and 18.33% of the samples, respectively. No significant differences between the groups in the 3-mm sections (P=0.126) were observed. There were significant differences in the 6-mm (P=0.042) and 9-mm sections (P<0.001). When WOG and PTN were used to perform root canal preparation, a significant difference was found in the average time (P=0.047). CONCLUSION: All the used instruments caused dentinal defects in the root dentin. All the instruments were used to perform the preparation with a similar average time.

Bacterial Reduction after Gutta-Percha Removal with Single vs. Multiple Instrument Systems.

INTRODUCTION: The aim of this study was to evaluate the effectiveness of a reciprocating single-instrument system (Reciproc-REC) compared with combined continuously rotating multiple-instrument systems [D-Race (DR) and BioRace (BR)] in reducing Enterococcus faecalis (E.f.) after gutta-percha removal. METHODS AND MATERIALS: Forty-six extracted human maxillary incisors were prepared and contaminated with E.f. strain (ATCC 29212) for 30 days. The samples were obturated and randomly divided into two experimental groups for gutta-percha removal (n=23): a REC group (R50) and a DR/BR group (DR1, DR2 and BR6). A standardized irrigation with 0.9% saline solution was performed. Root canal samples were taken with paper points before (S1) and after (S2) the removal of gutta-percha to establish bacterial quantification by culture. The time required for gutta-percha removal was also recorded. Positive and negative control groups (n=6) were used to test bacterial viability and control asepsis, respectively. Data were analysed using t-Student and one-way ANOVA tests (5% margin of error). RESULTS: The mean percentage of bacterial reduction was significantly higher in DR/BR group (84.2%) than in REC group (72.3%) (P<0.05). The mean time for obturation removal was 74.00 sec in REC group and 107.53 sec in DR/BR group (P<0.05). CONCLUSION: The combined continuously rotating multiple-instrument system was more effective in reducing bacteria after the removal of gutta-percha than the single-instrument system. None of the tested systems was able to completely eliminate root canal infection after gutta-percha removal. Thus, additional techniques should be considered.

Clinical Approach of Extensive Periapical Lesion with Periradicular Regenerative Surgery: A Case Report with 7 Year Follow Up

The aim of this study is to report a case of two maxillary incisors with chronic apical abscess and through-and-through lesion submitted to periradicular regenerative surgery, with clinical follow-ups and evaluation through cone-beam computerized tomography for 7 years. In the presentation, there was a persistent sinus tract in the palate and sensibility to touch at the apical region of the central and left lateral maxillary incisors. The initial tomography revealed the presence of an extensive radiolucent area in the apical third of the referred teeth, with loss of the buccal and palatal cortic es. For the treatment, a periradicular regenerative surgery was performed, an association of endodontic surgery with Guided Tissue Regeneration technique, using bovine bone xenograft and bioabsorbable membrane. The clinical and radiographic evaluations, including cone-beam computerized tomography, at seven years postoperatively, showed absence of symptomatology and sinus tract, probing depth within normal standards and apical bone neoformation.

El objetivo de este estudio fue reportar un caso de dos incisivos superiores con absceso apical crónico y lesión transversal sometidos a cirugía regenerativa perirradicular, con seguimiento clínico y evaluación mediante tomografía computarizada de haz cónico durante 7 años. En la presentación, había un trayecto sinusal persistente en el paladar y sensibilidad al tacto en la región apical de los incisivos maxilares laterales central y lateral izquierdo. La tomografía inicial reveló la presencia de una extensa zona radiolúcida en el tercio apical de los dientes referidos, con pérdida de las cortezas bucal y palatina. Para el tratamiento se realizó una cirugía regenerativa perirradicular, asociación de cirugía endodóntica con técnica de Regeneración Tisular Guiada, utilizando xenoinjerto óseo bovino y membrana bioabsorbible. Las evaluaciones clínicas y radiográficas, incluida la tomografía computarizada de haz cónico, a los siete años del posoperatorio, mostraron ausencia de sintomatología y tracto sinusal, profundidad de sondaje dentro de los estándares normales y neoformación ósea apical.

Evaluation of Apically Extruded Debris during Root Canal Retreatment Using ProTaper Next and Reciproc in Severely Curved Canals.

INTRODUCTION: To compare the apical extrusion of debris produced during root obturating material removal from severely curved root canals using either Reciproc (REC) or ProTaper Next (PTN) systems. METHODS AND MATERIALS: Twenty-six mesial canals of lower molars were instrumented, filled and allocated into two groups (n=13). Micro-computed tomographic images were performed to determine the root canal configuration (Vertucci's type IV) and initial volume of obturation. One Eppendorf tube was assigned per canal and weighed (10-4g) before and after removal of the obturating material. The difference between the initial and final weights was calculated and statistically evaluated. RESULTS: Apical extrusion of debris was confirmed in all samples, and the mean amount of apical extrusion was similar between both groups (0.061±0.014 g in PTN vs. 0.065±0.016 g in REC samples) (P<0.05). CONCLUSION: Both systems caused apical extrusion of debris with no differences between PTN and REC systems.

IL-17 E SUA RELAÇÃO COM AS LESÕES PERIRRADICULARES: REVISÃO DE LITERATURA / IL-17 AND ITS RELATIONSHIP TO PERIRRADICULAR INJURIES: LITERATURE REVIEW

A lesão perirradicular consiste em uma doença inflamatória de origem microbiana causada pelo desenvolvimento da infecção no sistema de canais radiculares. Citocinas pró-inflamatórias e imunoregulatórias são fundamentais para o desenvolvimento dessas lesões. No entanto, pouco se sabe sobre como e em que momento elas atuam nas diferentes fases de desenvolvimento da lesão. A presença de bactérias e seus subprodutos metabólicos evocam reações imunológicas do hospedeiro, como a chegada de diferentes células do sistema de defesa aos tecidos periapicais, bem como produção de mediadores inflamatórios. Diversos estudos vêm sendo realizados para identificar os mediadores envolvidos na atividade de reabsorção óssea, permitindo uma melhor compreensão sobre a etiopatogenia das periacopatias. Além disso, investigações prévias sugerem que os linfócitos T CD4+ são as célulasinflamatórias predominantes que se infiltram na patogênese das lesões periapicais e desempenham um papel importante no curso da doença. Células Th17, que compreendem uma subpopulação da T CD4+, cujo produto principal é a interleucina IL-17. A IL-17 é uma citocina pró-inflamatória que exerce efeitos potentes em diferentes tipos celulares da imunidade inata e é considerada uma ponte molecular entre o sistema imunológico inato e adaptativo. Ela também é responsável pelo início e propagação da inflamação, apresentando um papel importante na ligação da ativação da célula T para mobilização e ativação de neutrófilos. Neste contexto, a presente revisão da literatura discutiu o papel da IL-17 na formação e manutenção de lesões perirradiculares.

The periapical lesion is an inflammatory disease of microbial origin caused by infection development in the root canal system. Pro-inflammatory and immunoregulatory cytokines are essential for the development of these lesions. However, little is known about how and when they act in the different stages of injury development. The presence of bacteria and their metabolic products evoke host immune reactions, such as the arrival of different cells of the defense system in periapical tissues, as well as the production of inflammatory mediators. Several studies have been carried out to identify the mediators involved in bone resorption activity, allowing a better understanding of the etiopathogenesis of periapicopathies. In addition, previous investigations suggest that CD4 + T lymphocytes are the predominant inflammatory cells that infiltrate the pathogenesis of periapical lesions and play an important role in the course of the disease. Th17 cells, which comprise a subpopulation of CD4 + T, whose main product is interleukin IL-17. IL-17 is a pro-inflammatory cytokine that has potent effects on different cell types of innate immunity and is considered a molecular bridge between the innate and adaptive immune systems. It is also responsible for the onset and spread of inflammation, playing an important role in linking T cell activation to neutrophil mobilization and activation. In this context, the present literature review discussed the role of IL-17 in the formation and maintenance of periradicular lesions.

Efficacy of ProTaper NEXT Compared with Reciproc in Removing Obturation Material from Severely Curved Root Canals: A Micro-Computed Tomography Study.

INTRODUCTION: The aim of this study was to compare the remaining root canal obturation, volume of dentin removed, and apical transportation after retreatment of severely curved root canals by using Reciproc (REC) or ProTaper NEXT (PTN) systems. METHODS: Twenty-eight mesial canals of mandibular molars were instrumented and then obturated with gutta-percha and sealer and allocated into 2 balanced groups (n = 14), the REC group (R25 file) and the PTN group (X3 and X2 files). Micro-computed tomography analysis was performed to assess the percentage of residual obturation material, the amount of dentin removed, and apical transportation. The effective time for the removal of obturation and procedural errors were recorded. RESULTS: Obturation was effectively removed from the root canal in the REC and PTN groups (P ≤ .001), and the percentages of remaining obturation material were similar between both groups (84.8% PTN vs 86.5% REC) (P > .05). The amount of dentin removed (3.17 ± 2.64 mm(3) PTN versus 3.50 ± 2.82 mm(3) REC), apical transportation (at 1 mm: 0.096 ± 0.189 mm PTN versus 0.093 ± 0.186 mm REC; at 3 mm: 0.059 ± 0.069 mm PTN versus 0.082 ± 0.080 mm REC; at 5 mm: 0.097 ± 0.093 mm PTN versus 0.133 ± 0.138 mm REC), and the working time (269.69 ± 19.25 seconds PTN versus 268.62 ± 16.37 seconds REC) were also similar in both groups (P > .05). One file fractured in the REC group. CONCLUSIONS: Both systems were equally effective in the removal of obturation from severely curved canals and can be used for retreatment. Neither system could completely remove the obturation material; therefore, additional techniques are needed to improve cleaning of the root canal.

Shaping Ability of Single-file Systems with Different Movements: A Micro-computed Tomographic Study.

INTRODUCTION: This study aimed to perform a rigorous sample standardization and also evaluate the preparation of mesiobuccal (MB) root canals of maxillary molars with severe curvatures using two single-file engine-driven systems (WaveOne with reciprocating motion and OneShape with rotary movement), using micro-computed tomography (micro-CT). METHODS AND MATERIALS: Ten MB roots with single canals were included, uniformly distributed into two groups (n=5). The samples were prepared with a WaveOne or OneShape files. The shaping ability and amount of canal transportation were assessed by a comparison of the pre- and post-instrumentation micro-CT scans. The Kolmogorov-Smirnov and t-tests were used for statistical analysis. The level of significance was set at 0.05. RESULTS: Instrumentation of canals increased their surface area and volume. Canal transportation occurred in coronal, middle and apical thirds and no statistical difference was observed between the two systems (P>0.05). In apical third, significant differences were found between groups in canal roundness (in 3 mm level) and perimeter (in 3 and 4 mm levels) (P<0.05). CONCLUSION: The WaveOne and One Shape single-file systems were able to shape curved root canals, producing minor changes in the canal curvature.