XP-Endo Finisher behaviour and irrigant temperature in intracanal environment: Clinical measurements.

AIM: To evaluate the behaviour of the XP-Endo Finisher and the variation in the intracanal temperature of the irrigant at rest and when activated over time. METHODOLOGY: Differential scanning calorimetry (DSC) determined the transformation temperatures of XP-Endo Finisher instruments. A digital thermocouple was used to measure the temperature of the irrigant inside the pulp chamber. Two measurements were performed for each tooth (n = 12): with the irrigant at rest and during XP-Endo agitation for 60 s to observe the temperature evolution. The data were statistically analysed using a t-test with a confidence level of 95%. RESULTS: DSC results suggested that the XP-Endo Finisher had a mixed R-phase and austenitic structure at room temperature. The temperature values at predetermined time points (0, 10, 40, 70, 120 and 240 s) were measured, and no statistical difference was observed between the values of the resting and activated solutions at any of the selected points (p > .05). For the protocol performed with the XP-Endo file, the mean irrigant temperature observed at instrument insertion inside the root canal was 28.65°C. After 60 s of agitation, the temperature was 34.02°C. The solution temperature stabilized inside the canal only after 211 s at 35.5°C. The mean maximum irrigation solution temperature recorded inside the canal was 35.5°C without agitation and after XP-endo agitation (p > .05). CONCLUSIONS: Although the XP-Endo Finisher system does not promote heating of the irrigation solution, file expansion responsible for improved instrument cleaning starts at a temperature below the expected value.

Root canal conicity determination of primary second molars using nanotomography: An in vitro study.

BACKGROUND: The conicity of the root canals of primary teeth is an important measure for endodontic therapies. However, determining this conicity depends on the methods employed, which requires further investigation. AIM: The aim of this study was to determine the conicity of the root canals of the upper and lower primary second molars using nanotomography (nCT). DESIGN: An in vitro study was performed using nine primary second molars, both upper and lower, subjected to nCT. Comparisons between the diameters of root canals were performed between the thirds (cervical-D0, middle-D5, and apical-D7). The conicity (%) was determined for each root canal from cervical to apical. Data were statistically analyzed with a significance level of 5%. RESULTS: The conicity ranged from 2% to 8% for the upper primary second molars. Significant differences in root canal diameter between the thirds (D0, D5, and D7 points) were observed in the mesio- and distobuccal roots (p < .05), but not in the palatal roots (p > .05). For the lower primary second molars, the conicity ranged from 2% to 17%, as well as significant differences in root canal diameter between the thirds (D0, D5, and D7 points) were observed in all roots (distal, mesiobuccal, and mesiolingual; p < .05). CONCLUSION: The conicity of the upper primary second molars was different from that of the lower ones, which showed a greater variability.

Effect of radiotherapy, immediate dentin sealing and irrigation simulating single- or two-visits endodontic treatment on the bond strength to pulp chamber dentin: an in vitro study.

This study aimed to evaluate the influence of radiotherapy and different endodontic treatment protocols on the bond strength to pulp chamber dentin. Eighty mandibular molars were randomly divided into two groups (n = 40): non-irradiated and irradiated (60 Gy). The pulp chambers were sectioned, and each group was subdivided (n = 8), according to the endodontic treatment protocol: no treatment (Control); Single-visit; Two-visits; Immediate dentin sealing (IDS) + single-visit; and IDS + two-visits. Each endodontic treatment visit was simulated through irrigation with 2.5% NaOCl, 17% EDTA and distilled water. IDS was performed by actively applying two coats of a universal adhesive to the lateral walls of the pulp chamber. After, the pulp chambers were restored with resin composite and four sticks were obtained for microtensile test. In addition, the dentin of the pulp chamber roof was assessed for surface roughness, chemical composition, and topography after each treatment protocol. Two-way ANOVA, Tukey's post hoc, Mann-Whitney, Kruskal-Wallis and Dunn's post hoc were performed (α = 5%). The treatment protocol affected bond strength (p < 0.05), while the irradiation did not (p > 0.05). The control group presented the highest values (p < 0.05). The single-visit group demonstrated better performance compared to the other groups (p < 0.05), which did not differ from each other (p > 0.05) The use of IDS changed the surface roughness (p < 0.05), chemical composition (p < 0.05) and topography of the dentin. In conclusion, the treatment protocol influenced dentin adhesion, while irradiation did not.

Evaluation of pulp chamber temperature during cementation with the preheated composite resin technique.

STATEMENT OF PROBLEM: The cementation technique using preheated composite resin requires high temperatures for optimal execution and may lead to increased and damaging intrapulpal temperatures. Whether the technique can lead to a temperature increase that might lead to necrosis of the pulp tissue is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the temperature variation in the pulp chamber of bovine teeth with veneer-type preparations during veneer cementation using the preheated composite resin technique. MATERIAL AND METHODS: A total of 103 bovine incisors were divided into 8 groups (n=10) and prepared for indirect veneers with different preparation depths: 2.0 mm, 1.5 mm, 1.0 mm, and 0.5 mm. Veneers were cemented on these preparations using 2 cementation protocols: preheated composite resin and photopolymerizable resin cement. The teeth were attached to a device containing a temperature sensor which was inserted into the pulp chamber to quantify the intrapulpal temperature variation produced during the cementation protocols. The data were analyzed using a statistical software program. The level of statistical significance for the analyses was with a confidence interval of 95%, sampling power of 80%, and a moderate effect size (0.36). RESULTS: The groups cemented with preheated composite resin and the groups with the greatest preparation depth had the highest mean intrapulpal temperature; the PHC2 group presented a mean ±standard deviation temperature increase of 5.70 ±2.14 °C. CONCLUSIONS: The heat generated by heating the resin contributed to the increase in intrapulpal temperature. Temperature variations were greater in deeper preparations, especially when preheated resin technique was used.

Micro-computed tomographic evaluation of dentinal microcracks in response to progressive taper enlargement in root canals of maxillary molars.

AIM: To investigate the development of dentinal microcracks resulting from the progressive enlargement of the buccal canals of maxillary molars with and without the MB2 canal employing instruments with the same tip and four different tapers. METHODOLOGY: Twenty maxillary molars with (n = 10) and without (n = 10) the MB2 canal underwent micro-CT scanning. Their mesiobuccal and distobuccal canals were sequentially enlarged using nickel-titanium instruments with sizes 25/.03, 25/.05, 25/.06 and 25/.08v. Subsequent scans were conducted after each canal enlargement. The preoperative scans were coregistered with their respective datasets, and the cross-sectional images were carefully examined to identify dentinal defects. This process, conducted twice at two-week intervals, involved two examiners. Intra- and inter-examiner calibrations were validated using the Kappa index. The incidence of microcracks was reported as a percentage frequency. RESULTS: The intra- and inter-examiner Kappa values were 0.85 and 0.88, respectively, indicating excellent agreement. Dentinal microcracks were detected in 1206 out of 42 975 cross-sectional image slices (2.8%). Molars with MB2 canal exhibited more slices (4.5%) than teeth without MB2 (0.9%). Every dentinal microcrack observed in the images after root canal preparation was already present in the corresponding images taken before root canal preparation. CONCLUSION: The progressive enlargement of root canals using instruments with different tapers did not induce the formation of new dentinal microcracks in maxillary molars, regardless of the presence of the MB2 canal.

Decrease from main root canal and intratubular Fusobacterium nucleatum and its endotoxin after ultrasonic activation of conventional and alternative irrigation solutions.

This study evaluated conventional and alternative irrigation solutions combined with ultrasonic irrigant activation (UIA) against Fusobacterium nucleatum (F. nucleatum) and its endotoxin (LPS) in main root canal and dentinal tubules, using a new intratubular infection model. Seventy dentin cylinders were infected with F. nucleatum for seven days under anaerobic conditions and treated with 2.5% sodium hypochlorite (NaOCl), limewater + 2.5% NaOCl, and 10% ethanolic propolis extract (EEP), administered by syringe irrigation (SI) or UIA. Microbiological samples were collected before and after irrigation to determine CFU ml-1 and LPS levels. Confocal microscopy assessed bacterial membrane damage with Live/Dead staining. Irrigation solutions effectively reduced CFU ml-1. UIA caused greater damage to the bacterial membranes and reduced LPS levels. The ultrasonic activation of 10% EEP and limewater + 2.5% NaOCl were comparable to 2.5% NaOCl (p > 0.05). UIA improved the effectiveness of solutions, suggesting potential for alternative substances. Randomized clinical trials using these protocols are recommended.

Effect of an experimental desensitizer with a hydroxyapatite-capsaicin composite applied before in-office dental bleaching on hydrogen peroxide diffusion, color and surface changes.

OBJECTIVE: To evaluate a prior application of an experimental desensitizer containing a hydroxyapatite-capsaicin composite (HAp-CAP) in different concentrations on hydrogen peroxide (HP) diffusion into the pulp chamber, bleaching efficacy (BE) and on physical and chemical alterations of the enamel surface after in-office bleaching. MATERIALS AND METHODS: Forty sound premolars were randomized in five groups according to each experimental condition (n = 8): no bleaching (negative control), only bleaching (positive control), 0.1%, 1% and 5% of HAp-CAP. Four groups were submitted to in-office bleaching (HP 35%) post-desensitizer application. The HP concentration (µg/mL) on the pulp chamber was measured by UV-Vis spectrophotometer. The BE was measured by digital spectrophotometer (ΔEab, ΔE00 and ΔWID) before and after 7 days bleaching. Enamel tooth fragments obtained from twenty molars were submitted to the same experimental conditions and analyzed using FE-SEM and EDS, Vickers microhardness (VHN), Raman spectroscopy, and nanoroughness (Ra) by AFM to evaluate morphologic and chemical changes on enamel surface. All data were submitted to statistical analysis (α = 0.05). RESULTS: The groups treated with HAp-CAP exhibited a lower concentration of HP in the pulp chamber compared to only bleaching group (p < 0.05). There were no significant differences observed in BE between HAp-CAP groups and only bleaching group (p > 0.05). Only HAp-CAP 5% showed no significant differences in VHN values when compared to no bleaching group (p > 0.05). There were no significant differences among any group in Ra values (p > 0.05). The groups submitted to HAp-CAP showed a higher mineral concentration when compared to only bleaching group (p < 0.05). CONCLUSION: Desensitizers containing HAp-CAP up to 5% effectively reduce HP diffusion into the pulp chamber after in-office bleaching, without interfering to BE and Ra, as well as prevent enamel demineralization. CLINICAL RELEVANCE: The use of desensitizers containing HAp-CAP during in-office bleaching treatments offers a promising approach to reduce the risk of pulp irritation caused by hydrogen peroxide diffusion, without compromising the bleaching effectiveness or causing surface roughness.

Supplementary methods for filling material removal: A systematic review and meta-analysis of micro-CT imaging studies.

OBJECTIVE: To evaluate the efficacy of supplementary methods, including Passive Ultrasonic Irrigation (PUI), ultrasonic inserts, XP-Endo Finisher, XP-Endo Finisher R, Easy Clean, sonic activation, and the Er:YAG laser (SWEEPS), in removing residual filling material (RFM) during endodontic retreatment. METHOD: Five electronic databases and gray literature were searched on May 5, 2024. Two independent reviewers selected laboratory studies that assessed the efficacy of supplementary methods for RFM removal using micro-CT imaging. The methodological quality of the studies was evaluated using the Joanna Briggs Institute Critical Appraisal Checklist for Quasi-Experimental Studies. A meta-analysis was conducted to compare the pooled mean values of initial and final RFM volumes after the use of different supplementary methods. RESULTS: Thirty-two studies were included in the qualitative analysis, and seventeen were included in the meta-analyses. Only seven studies (21.9 %) fulfilled all criteria of the methodological quality checklist. No supplementary method has been able to eradicate RFM from root canals. However, the quantitative analysis demonstrated that using PUI, ultrasonic inserts, XP-Endo Finisher, and XP-Endo Finisher R instruments effectively reduced RFM (p < 0.05). In contrast, Easy Clean, sonic activation, and Er:YAG laser (SWEEPS) did not demonstrate a significant reduction (p > 0.05). CONCLUSION: Supplementary methods were unable to completely remove RFM from the canal walls during endodontic retreatment. However, the use of PUI, ultrasonic inserts, XP-Endo Finisher, and XP-Endo Finisher R instruments has been shown to significantly reduce the amount of RFM. CLINICAL SIGNIFICANCE: Clinicians are encouraged to incorporate supplementary methods for filling material removal during endodontic retreatment to enhance the cleaning of root canal walls.

Calcium silicate-based intracanal medication: Physicochemical properties and effectiveness of techniques for removing medication from the human root canal.

OBJECTIVE: Our purpose was to investigate the physicochemical properties of Bio-C Temp, a bioceramic intracanal medication, and whether its residues remain adhered to the dentine walls after conventional manual irrigation (CMI) or passive ultrasonic irrigation (PUI) in comparison to Calen. METHODS: The pH after 12 hours, 1 day, 3 days, 7 days, 14 days, 21 days and 28 days, and the flow, radiopacity, and the solubility of the medications after immersion for 7 and 30 days in distilled water (dH2O) or phosphate-buffered saline (PBS) solution were evaluated. Filling capacity, and volumetric changes after 14 days were assessed by micro-computed tomography (micro-CT). The residues of medications after CMI or PUI were analysed with scanning electron microscopy. Statistical analysis was performed using ANOVA and Tukey's post-hoc test, Student's t test or the Kruskal-Wallis and Dunn post-hoc test (α = 0.05). RESULTS: Bio-C Temp presented a lower pH, flow, volumetric change, and weight loss after immersion in PBS on the 7th and 14th days (p < 0.05) and greater radiopacity and filling capacity (p < 0.05) than Calen. Both medications showed lower solubility in PBS than in dH2O (p < 0.05). There was no difference in the residue content of the two medications between two irrigation methods in three-thirds of the roots (p > 0.05). CONCLUSION: Although Bio-C Temp had less volumetric loss and satisfactory filling capacity, this medication provided lower alkalinity than did Calen. Furthermore, neither CMI nor PUI completely removed the medicament residues within the human root canal.

Hydrogen Peroxide in the Pulp Chamber and Color Change in Maxillary Anterior Teeth After In-Office Bleaching.

While the literature has noted variations in hydrogen peroxide (HP) permeability, and consequently, tooth sensitivity among different types of anterior teeth, there is a scarcity of research on this specific topic. This study evaluated HP permeability and color change (CC) in different groups of human maxillary anterior teeth (canines, lateral incisors, and central incisors) after in-office bleaching with HP at 35%. Thirty teeth maxillary anterior (n=10) were bleached with HP at 35% gel in one session of three 15-minutes applications. Buccal thickness (mm) was measured from images obtained using cone beam computed tomography. The concentration of HP (µg/mL) that reached the pulp chamber was assessed using UV-Vis spectrophotometry. CC (WID, ∆Eab, and ∆E00) was evaluated before and after bleaching with a digital spectrophotometer. One-way ANOVA and Tukey's test were applied to statistically evaluate the data for buccal thickness, HP permeability, and CC (α=0.05). Comparison between thickness and HP permeability was performed using Pearson's correlation. Thicker teeth, such as canines, had lower HP amounts inside the pulp chamber compared to central and lateral incisors. Despite the significant effect of buccal thickness on HP permeability (p<0.05), no correlation was found between the two factors. CC was similar across tooth types (p>0.05). The difference in buccal thickness among the superior anterior teeth does not interfere with CC. However, a thinner buccal wall thickness is associated with greater HP permeability detected in the pulp after in-office bleaching.

Prevalence of pulp canal obliteration after traumatic dental injuries: a systematic review and meta-analysis.

This systematic review aimed to answer the following question: What is the estimated prevalence of pulp canal obliteration in subtypes of traumatic dental injury (TDI) in deciduous and permanent teeth? The searches were conducted in PubMed, Embase, Scopus, Web of Science, LILACS, Grey Literature, and Google Scholar, and complemented by a manual search, until April 16th, 2023. Observational studies were selected based on population, exposure, and outcome (PEO) (P, deciduous or permanent teeth; E, TDI; O, pulp canal obliteration). Two reviewers (kappa 0.90) applied the eligibility criteria, extracted qualitative data, and assessed the methodological quality using the Newcastle-Ottawa tool. A meta-analysis was performed using MedCalc 17.2. Thirty-four articles were selected after screening. The methodological quality was moderate to high. The estimated prevalence of pulp canal obliteration was 27.6% (95%CI: 18.7-37.7) and 21.9% (95%CI:16.0-28.4), for permanent and deciduous teeth, respectively. Considering the TDI subtypes, the prevalence of pulp canal obliteration was higher in root fractures of the permanent teeth (78.6 %, 95%CI: 62.8-90.9) and lateral luxation injuries in deciduous teeth (29.4%, 95%CI:19.1-41.0). Our review of 34 articles of moderate and high methodological quality found that the prevalence of pulpal canal obliteration ranges from 21.9% to 27.6%. Pulp canal obliteration was most frequently detected following lateral luxation injuries of the deciduous teeth and root fractures of the permanent teeth (PROSPERO CRD42020179438).

Antimicrobial and anti-endotoxin activity of N-acetylcysteine, calcium hydroxide and their combination against Enterococcus faecalis, Escherichia coli and lipopolysaccharides.

Background: The management of endodontic infections is a complex challenge, mainly due to the involvement of diverse microorganisms and their by-products. This study aimed to evaluate the efficacy of N-acetylcysteine (NAC), calcium hydroxide (Ca(OH)2), and their combined application as intracanal medications in combating Enterococcus faecalis, Escherichia coli, and lipopolysaccharides (LPS) from E. coli. Methods: A total of 60 single-rooted human teeth were carefully selected and divided into six groups. These tooth canals were deliberately exposed to E. faecalis (ATCC 29212) and E. coli (ATCC 25922) to induce biofilm formation. Subsequently, the specimens were treated with NAC, Ca(OH)2, or a combination of both substances. Three samples of the root canals were collected at three moments: the first sample (S1) was to confirm the initial contamination, the second sample (S2) was immediately post-instrumentation, and the third sample (S3) was collected after the use of the intracanal medication. The antimicrobial efficacy of these intracanal medications was assessed by enumerating colony-forming units per milliliter (CFU/mL). In addition to this, the kinetic chromogenic Limulus Amebocyte Lysate (LAL) assay by Lonza was used to quantify LPS from E. coli. Data tested for normality; then, Kruskal-Wallis and Friedman tests were used, and Dunn's for multiple comparisons. Results: The findings of this study showed significant reductions in the microbial load of E. faecalis and E. coli by S3. Notably, there were no statistically significant differences among the treatment groups concerning these microorganisms. However, it was observed that only the combination of NAC and Ca(OH)2 led to a noteworthy decrease in the quantity of E. coli's LPS after 7-days, demonstrating a statistically significant difference from the other treatment groups. NAC + Ca(OH)2 combination, applied for a duration of 7-days, proved to be more suitable in reducing the presence of E. faecalis, E. coli, and LPS from E. coli within the context of endodontic infections.

Comparative analysis of methods for measuring root canal curvature based on periapical radiography: A laboratory study.

AIM: To evaluate the agreement between six currently available periapical radiography-based methods for measuring the root canal curvatures in mesial roots of mandibular first molars, assessed by two examiners with different proficiency levels. METHODOLOGY: Non-endodontically treated mesial roots of 41 human mandibular first molars were radiographed using the parallelling technique. Two independent observers (a specialist in endodontics and radiology and a final-year dental student) assessed their root canal curvature using the methodologies described by Schneider (1971, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 32, 271), Weine (1982, Endodontic therapy), Berbert and Nishiyama (1994, Revista Gaúcha de Odontología, 356), Luiten et al. (1995, Journal of Endodontics, 21, 26), Hankins and ElDeeb (1996, Journal of Endodontics, 22, 123) and Pettiette et al. (1999, Journal of Endodontics, 25, 230). Intra- and inter-examiner reliability was assessed using the intraclass correlation coefficient. The differences in curvature angle measured by the different methods were compared using the one-way anova for repeated measures test, followed by Tukey's post hoc analysis. The effect was calculated using the Cohen's d method. To determine the agreement between methods, the Bland-Altman analysis was used. The significance level was set at 5%. RESULTS: Agreement for the observers was excellent (>0.81) for the six methods considered. For the angle comparisons between methods, the maximum differences were for Schneider versus Weine (35.77°) and Luiten versus Hankins (35.14°), whilst the highest percentage of angles with a difference >10° were Weine versus Luiten and Berbert versus Pettiette (90%) and the comparison Weine versus Hankins presented with the lowest frequency (15%). Excellent agreement was found for five comparisons: Weine versus Luiten (0.940), Berbert versus Pettiette (0.917), Weine versus Pettiette (0.907), Luiten versus Pettiette (0.904) and Berbert versus Luiten (0.812). Compared to Schneider's method, the other methods showed a tendency of increasing difference as the angles became more acute. The other methods exhibited linear differences, remaining constant for smaller and larger angles. CONCLUSIONS: Reliability was excellent for all methods assessed separately. Maximum differences in curvature angles were found when comparing Schneider versus Weine and Luiten versus Hankins. Excellent agreement was found for Weine versus Luiten, Berbert versus Pettiette, Weine versus Pettiette, Luiten versus Pettiette and Berbert versus Luiten. In the presence of dilacerations, the method by Schneider was less sensitive.

Comparative analysis of hydrophobicity and dentin adhesion ability in Candida albicans strains.

OBJECTIVE: Adhesion to dentin is a first step for a successful microbial root canal colonization. Cell hydrophobicity seems to have some influence in the Candida species adhesion to surfaces. To measure cell surface hydrophobicity and to investigate the adherence ability to human dentin among Candida albicans strains isolated from root canal and lingual dorsum via an in vitro study. METHODOLOGY: adhesion was quantified in function of dentin area covered by blastospores and/or hyphae presence detected by epifluorescence microscope. Cell surface hydrophobicity was estimated by assessing the percentage migration of cells from an aqueous phase to a hydrocarbon phase. Contact angles were measured by the sessile drop technique on the dentin surface using a contact angle measurements apparatus. We also examined the correlation between adhesion ability and hydrophobicity. RESULTS: although there was some intra-species variation in cell surface hydrophobicity, most isolates were characterized by moderate hydrophobicity. There was no significant difference in this parameter when the isolation niche was considered. Both root canal and lingual dorsum yeasts were able to adhere to dentin. No association was found between the strains' site of isolation and adhesion. Moreover, cell surface hydrophobicity and adhesion ability were not correlated. CONCLUSION: although hydrophobicity can influence Candida albicans virulence in many ways, this study suggests that this parameter by itself was not a good predictor of adhesion to dentin.

CBCT assessment of mandibular molar furcation following root canal retreatment using engine-driven instruments.

This study employed e-Vol DXS cone beam computed tomography (CBCT) software to assess dentin remnants in the furcation area of mesial canals in mandibular molars during root canal retreatment (RCR). Four groups (Reciproc®, ProTaper Next®, Race Evo®, Protaper Gold®) were subjected to RCR, and CBCT images were captured before (T1) and after (T2) treatment. Measurements of remaining dentin thickness at 1 mm and 3 mm below the furcation were scrutinized. Results revealed no significant differences in mean thicknesses of mesiobuccal (MB) and mesiolingual (ML) canals at 1 mm and 3 mm from the furcation pre-treatment (T1). Post-treatment (T2) showed analogous findings, with no significant differences in mean thicknesses. However, disparities were found between MB and ML canals at both distances, both before and after retreatment. In essence, the evaluated instruments exhibited safety in RCR, implying that they are appropriate for use in critical areas of mandibular molars without inducing excessive wear. This study underscores the reliability of these instruments in navigating danger zones during RCR, and contributes valuable insights for dental practitioners who handle complex root canal scenarios in mandibular molars.

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.

α-IRAK-4 Suppresses the Activation of RANK/RANKL Pathway on Macrophages Exposed to Endodontic Microorganisms.

Periapical lesions are common pathologies affecting the alveolar bone, often initiated by intraradicular lesions resulting from microbial exposure to dental pulp. These microorganisms trigger inflammatory and immune responses. When endodontic treatment fails to eliminate the infection, periapical lesions persist, leading to bone loss. The RANK/RANKL/OPG pathway plays a crucial role in both the formation and the destruction of the bone. In this study, the objective was to inhibit the RANK/RANKL pathway in vitro within exposed Thp-1 macrophages to endodontic microorganisms, specifically Enterococcus faecalis, which was isolated from root canals of 20 patients with endodontic secondary/persistent infection, symptomatic and asymptomatic, and utilizing an α-IRAK-4 inhibitor, we introduced endodontic microorganisms and/or lipoteichoic acid from Streptococcus spp. to cellular cultures in a culture plate, containing thp-1 cells and/or PBMC from patients with apical periodontitis. Subsequently, we assessed the percentages of RANK+, RANKL+, and OPG+ cells through flow cytometry and measured the levels of several inflammatory cytokines (IL-1ß, TNF-α, IL-6, IL-8, IL-10, and IL-12p70) in the cellular culture supernatant through a CBA kit and performed analysis by flow cytometry. A significant difference was observed in the percentages of RANK+RANKL+, OPG+ RANKL+ cells in thp-1 cells and PBMCs from patients with apical periodontitis. The findings revealed significant differences in the percentages of the evaluated cells, highlighting the novel role of the IRAK-4 inhibitor in addressing this oral pathology, apical periodontitis, where bone destruction is observed.

Negotiating and Treating Lateral Canals: Report of 7 Cases.

This is a series of 7 cases in which the operator penetrated lateral canals with instruments. Two teeth presented with irreversible pulpitis, 4 with necrotic pulps, and 1 with previous treatment. Except for the teeth with pulpitis, all the others were associated with apical periodontitis. The main root canal was always relatively straight, with the lateral canals at the middle third of the root. Suggestive images of lateral canal presence were seen on periapical radiographs in five cases. The clinician introduced intentionally small hand instruments in the lateral canal in 5 cases, while the penetration was fortuitous in the others. The lateral canals were obturated in all cases. Follow-up examination was possible in five cases, all of them showed evidence of successful clinical and radiographic outcomes. Introducing files into lateral canals may permit some preparation and penetration of irrigant solution, favoring disinfection and, consequently, enhancing the treatment outcome. (EEJ-2023-05-063).

Exploración del conducto en C con tomografía computada de haz cónico / Exploration of C-shaped canals with cone-beam computed tomography

El «conducto en C¼ es un tipo de anatomía dentaria compleja que debe ser evaluado previo a la realiza- ción de un tratamiento endodóntico. Esta variación anatómica es vista principalmente en segundos mola- res inferiores aunque también puede encontrarse en premolares y molares, tanto superior como inferior. Para su diagnóstico se solicitan distintos tipos de estudios imagenológicos. Debemos tener en cuenta que este tipo de anatomía no es observado fácilmen- te en imágenes bidimensionales por lo cual es muy importante considerar para estos casos complejos, la solicitud de un estudio de alta complejidad como lo es la tomografía computada de haz cónico, la cual nos permitirá explorar este tipo de anatomía para tenerlo en cuenta al momento de realizar un correcto aborda- je del conducto en C (AU)

The "C-canal" is a type of complex dental anatomy that must be evaluated prior to performing endodontic treatment. This anatomical variation is seen mainly in lower second molars although it can also be found in premolars and molars, both upper and lower. For its diagnosis we can use different types of imaging studies. We must keep in mind that this type of anatomy is not easily observed in two-dimensional images, which is why it is very important to consider, for these complex cases, the request for a highly complex study such as cone beam computed tomography, which will allow us to explore this type of anatomy to take it into account when performing a correct approach to the C-duct (AU)

Effect of the filling technique on the filling removal from oval-shaped canals.

OBJECTIVES: This ex vivo study aimed to evaluate the influence of different filling techniques on the filling removal from oval root canals filled with bioceramic sealer. METHODS: Thirty-six mandibular incisors with single oval canals were filled with bioceramic sealer following the techniques (n = 12): single-cone, modified McSpadden, or continuous wave of condensation, and scanned by micro-computed tomography (micro-CT). The filling was removed using the Clearsonic ultrasound tip and Reciproc system up to the R40 instrument, and the working time was recorded. The teeth were scanned again by micro-CT. Percentage of remnant volume (mm³) of the filling material, dentin thickness, and root canal transportation were measured. The data was analyzed using parametric and non-parametric tests with a significance level of 5%. RESULTS: It took more time to remove the filling material using the continuous wave of condensation technique (p < 0.05), followed by the modified McSpadden and single-cone techniques. There was no difference (p > 0.05) when comparing the percentage of remaining filling material among the three groups, nor did it among the segments of each tooth. There was also no difference in the analysis of dentin thickness and transportation when comparing the groups (p > 0.05). CONCLUSIONS: The filling technique did not influence the amount of remaining filling material, dentin thickness, and transportation. The working time was longer with thermoplastic filling techniques. CLINICAL RELEVANCE: Endodontic retreatment in teeth filled with bioceramic sealers increases with their use. Several techniques are used to fill the root canals, thus, it is important to know whether the filling technique influences the non-surgical endodontic retreatment.