Endotoxin levels after chemomechanical preparation of root canals with sodium hypochlorite or chlorhexidine: a systematic review of clinical trials and meta-analysis.

AIM: The aim of this systematic review was to answer the following question: in patients with primary endodontic infection, is there a statistically significant difference in the endotoxin levels after chemomechanical preparation with sodium hypochlorite (NaOCl) or chlorhexidine (CHX)? METHODOLOGY: A protocol was prepared and registered on PROSPERO (CRD42017069996). Four electronic databases (MEDLINE via PubMeb, Scopus, Web of Science and Cochrane Library) were searched from their start dates to 1 March 2017 using strict inclusion and exclusion criteria and reviewed following PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Only clinical trials (randomized and nonrandomized) that compared the effectiveness of NaOCl and CHX to reduce endotoxins during chemomechanical preparation of teeth with primary endodontic infection were included. Two reviewers independently assessed the eligibility for inclusion, extracted data and assessed the quality using the risk of bias tool. RESULTS: From 712 articles that resulted from the initial search, 37 studies were included for full-text appraisal; four studies met the inclusion criteria for quantitative synthesis. A single meta-analysis was performed to compare the endotoxin levels before and after chemomechanical preparation with NaOCl or CHX. The forest plot of lipopolysaccharide (LPS) levels indicated that the data were heterogeneous [I2  = 63.9%; Tau2  = 574.5 (P = 0.04)]. The use of NaOCl and CHX during chemomechanical preparation significantly reduced the LPS levels compared to the initial ones. CONCLUSIONS: Chemomechanical canal preparation with both NaOCl and CHX reduced the endotoxin levels compared to the initial ones found in primary endodontic infections. When NaOCl was used during chemomechanical preparation, endotoxins levels were lower than those obtained after chemomechanical preparation with CHX.

Influence of apical enlargement and complementary canal preparation with the Self-Adjusting File on endotoxin reduction in retreatment cases.

AIM: To compare the effectiveness of large apical preparations and complementary canal preparation with the Self-Adjusting File (SAF) in removing endotoxins from the root canal of teeth with apical periodontitis. METHODOLOGY: Ten single-rooted and single-canaled teeth with post-treatment apical periodontitis were selected. Endotoxin samples were taken after removal of the root filling (S1), after chemomechanical preparation (CMP) using 2.5% NaOCl and an R25 file (S2), after CMP using 2.5% NaOCl and an R40 file (S3) and after complementary CMP using the SAF system (S4). Limulus amebocyte lysate (LAL) was used to measure endotoxin levels. The Friedman and Wilcoxon tests were used to compare endotoxin levels at each clinical intervention (P < 0.05). RESULTS: After root filling removal, endotoxin was detected in 100% of the root canals (S1, 4.84 EU mL-1 ). CMP with the R25 file was able to significantly reduce endotoxin levels (P < 0.05). Increased levels of endotoxin removal were achieved by apical preparation with the R40 file (P < 0.05). Complementary CMP with SAF did not significantly reduce endotoxin levels (P > 0.05) following the use of the R40 instrument. CONCLUSIONS: Apical enlargement protocols were effective in significantly reducing endotoxin levels. Complementary preparation with the SAF system failed to eliminate residual endotoxin contents beyond those obtained with the R40 instrument.

Clinical efficacy of EDTA ultrasonic activation in the reduction of endotoxins and cultivable bacteria.

AIM: This clinical study was conducted to investigate the influence of 17% ethylenediaminetetraacetic acid (EDTA) ultrasonic activation after chemomechanical preparation (CMP) on eliminating/reducing oral bacterial lipopolysaccharides (known as endotoxins) and cultivable bacteria in teeth with pulp necrosis and apical periodontitis. METHODOLOGY: Samples were taken from 24 root canals at several clinical periods: S1 - before CMP; S2 - after CMP; S3 - after EDTA: G1 - with ultrasonic activation (n = 12) and G2 - without ultrasonic activation (n = 12). Root canals were instrumented using Mtwo rotary files. Culture techniques were used to determine the number of colony-forming units (CFU). Limulus amebocyte lysate (LAL) was used to measure endotoxin levels. Friedman's and Wilcoxon signed-rank tests were used to compare the amount of bacteria and endotoxin levels in each period (P < 0.05). RESULTS: Endotoxins and cultivable bacteria were recovered in 100% of the initial samples (S1). CMP was effective in reducing endotoxins and bacterial load (all with P < 0.05). Higher values of endotoxin reduction were achieved with EDTA ultrasonic activation [G1, 0.02 EU mL-1 (range 0.01-0.75)] compared with the no activation group [G2, 1.13 EU mL-1 (range 0.01-8.34)] (P < 0.05). Regarding bacterial reduction, no statistically significant difference was found in S3, regardless of the group (G1, G2, P > 0.05). CONCLUSIONS: Chemomechanical preparation was effective in reducing bacteria and endotoxins, but could not completely eliminate them. The ultrasonic activation of EDTA was effective in further reducing endotoxin levels in the root canals of teeth with pulp necrosis and apical periodontitis.

Root canal content from primary endodontic infection and upregulation of gelatinases in fibroblast cells.

AIM: To investigate endotoxin levels from primary endodontic infections before and after chemomechanical preparation (CMP) and to determine their antigenicity against 3T3 fibroblasts through gelatinolytic activity of matrix metalloproteinases (MMPs). METHODOLOGY: Twenty-four root canals with primary endodontic infection and apical periodontitis were selected. Samples were collected using paper points before (S1) and after chemomechanical preparation (CMP) (S2). The limulus amebocyte lysate assay was used for endotoxin measurement. Fibroblasts were stimulated with root canal contents for 24 h. Supernatants of cell cultures stimulated with root canal contents were collected after 24 h to determine the levels of MMP-2 and MMP-9 gelatinolytic activity using the zymography technique. Friedman and Wilcoxon tests were used to compare the amount of endotoxin before (S1) and after CMP (S2) (P < 0.05). Data obtained from gelatinolytic activity were analysed using anova and Tukey's tests (P < 0.05). RESULTS: Endotoxin was recovered in 100% of the samples. There was a significant reduction in endotoxin levels after CMP (P < 0.05). A correlation was found between the levels of endotoxins and MMP-2 expression (P < 0.05). Root canal contents of initial samples (S1) induced significantly greater MMP-2 expression by fibroblasts when compared to S2 and the nonstimulated group (P < 0.05). No gelatinolytic activity of MMP-9 was observed in S1, S2 and control group. CONCLUSIONS: Root canal contents from primary endodontic infections had gelatinolytic activity for MMP-2. Moreover, CMP was effective in reducing endotoxin levels and their antigenicity against fibroblasts on gelatinolytic activity.

Evaluation of the multifrequency electronic apex locator Joypex 5 in primary teeth.

AIM: To evaluate ex vivo the accuracy of the multifrequency electronic apex locator (EAL) Joypex 5 in primary molars. METHODS: Fourteen primary molars were selected for a total of 25 root canals. Working length measurements were performed by direct observation (DO), using a 15 K-file into the root canal until its tip was visible at the apical foramen and electronically using the EALs Joypex 5. Data were analysed statistically using the intraclass correlation coefficient (ICC). To assess whether a significant difference in accuracy of the electronic apex locator existed, the Student's t test was performed at 5% significance. RESULTS: No statistical difference was observed between the direct observation and the EAL measurement (p < 0.05). The ICC confirmed the agreement of different methods to measure canal length. The R(2) coefficient was close to 1, denoting a strong agreement between measures obtained with Joypex 5 and DO. CONCLUSION: The multifrequency EALs Joypex 5 showed adequate accuracy in the root length determination of primary teeth.

Localización efectiva de un segundo conducto radicular en incisivos inferiores mediante magnificación, radiografía y diafanización / Effective location a second root canal in lower incisors by magnification radiography and diaphanization

Objetivo: Evaluar in vitro, la efectividad del método visual y radiográfico, comparándolos con la técnica de diafanización en la detección del segundo conducto radicular de incisivos inferiores tratados endodónticamente. Material y métodos: Fueron analizados 133 dientes incisivos inferiores permanentes, tratados endodónticamente, a través de métodos visuales (con y sin auxilio de magnificación), radiográficos y de diafanización. El análisis radiográfico fue realizado en negatoscopio utilizando una lupa estereoscópica (10X). Posteriormente, fue realizada la remoción completa de la obstrucción provisional para la exploración visual con y sin auxilio de microscopio clínico (MO) en un aumento de 12X. Finalmente los dientes fueron diafanizados y almacenados en salicilato de metila para posterior análisis. Dos evaluadores calibrados registraron los datos referentes a la presencia o no del segundo conducto radicular para cada uno de los métodos utilizados. Resultados: El análisis radiográfico mostró la presencia del segundo conducto en 24 dientes (18,05%. Visualmente, fue encontrado en 4 dientes (3,00%) sin magnificación y en 16 dientes (12,03%) con ayuda del MO. A través de la diafanización, 34 dientes (25,95%) presentaron segundo conducto. Conclusiones: La asociación de técnicas radiográficas y la magnificación visual obtenida con la utilización del MO se muestran como los aliados clínicos más efectivos para la localización del segundo conducto en incisivos inferiores.

Objective: To evaluate in vitro the effectiveness of the visual, radiographic and clearing technique on detection of two root canals in mandibular incisor teeth endodontically treated. Material and methods: One hundred thirty-three human permanent lower incisors were anlyzed through visual methods (with and without magnification), radiographic and clearing technique. Radiographic analysis was performed in light box using a stereomicroscope (10X). Then, the temporary filling of al specimens was removed for visual exploration with and without clinical microscope (OM) (12X). Finally the teeth were submitted to clearing technique and stored in methyl salicylate for subsequent analysis. Two calibrated reviewers recorded data about the presence or absence of the second root canal for each of the used methods. Results: Radiographic analysis showed the presence of the second root canal in 24 teeth (18.05%). Visually, it was found in 4 teeth (3.00%) and 16 teeth (12.03%) without and with the use of OM, respectively. Through clearing technique, in 334 teeth (25.95%) it was found the second root canal. Conclusion: The association of radiographic techniques and visual magnification with the use of MO has been shown as the most effective clinical partners to locate the second root canal in mandibular incisors.

Evaluation of the Joypex 5 and Root ZX II: an in vivo and ex vivo study.

AIM: To evaluate in vivo and ex vivo the accuracy of the multifrequency electronic root canal length measurement device (ERCLMD) Joypex 5 and compare it with the Root ZX II. The ex vivo methodology for evaluation of the accuracy of ERCLMDs was also validated by comparison with in vivo results. METHODOLOGY: Twenty single-rooted human teeth that were scheduled for extraction were selected. Working length measurements were performed in vivo with the Joypex 5 and Root ZX II. After the teeth were extracted, each canal was measured with the ERCLMDs ex vivo. Then, a size 15 K-file was used to determine the reference working length (RWL), which was established 0.5 mm from the major foramen by direct observation. The measurements of working length obtained with the different methods and ERCLMDs were compared by analysis of variance and Tukey's test at P < .05. Statistical correlations were also performed. RESULTS: No significant difference was observed between in vivo and ex vivo measurements or the different types of ERCLMDs. The Bland-Altman plot confirmed the agreement of different methods and ERCLMDs to measure canal length. The R(2) coefficient obtained in both situations, comparing the ERCLMDs, was close to 1, denoting a strong agreement between measurements obtained with the Joypex 5 and Root ZX II and between in vivo and ex vivo methodologies. CONCLUSION: The Joypex 5 and Root ZX II had similar accuracy in determining working length of root canals. The ex vivo methodology for evaluation of the accuracy of ERCLMDs was validated when compared with the in vivo results.

Evaluation of cytotoxicity and up-regulation of gelatinases in fibroblast cells by three root repair materials.

AIM: To investigate the effects of root repair materials on the cytotoxicity and gelatinolytic activity of matrix metalloproteinases (MMPs) in 3T3 fibroblasts. METHODOLOGY: Fibroblasts (3T3, 3 × 10(5) cells per well) were incubated with elutes of calcium hydroxide (Biodinâmica, Ibiporã, PR, Brazil), EndoBinder (Binderware, São Carlos, SP, Brazil) and mineral trioxide aggregate (MTA) (Angelus, Londrina, PR, Brazil) for 24 h. The cytotoxicity of all root repair materials was determined using the MTT assay. Supernatants of cell cultures incubated with materials were collected after 24 h to determine the levels of MMP-2 and MMP-9 gelatinolytic activity by gelatin zymography. Data were analysed using anova and Tukey's test. RESULTS: Cells secreted MMP-2 after 24 h with calcium hydroxide inducing significantly greater MMP-2 expression in relation to the control and the other root repair materials (P < 0.05). The cytotoxicity results revealed that there was no significant difference in the cell viability of MTA, EndoBinder and the control group. However, there was a significantly reduced cell viability of 3T3 fibroblasts in association with calcium hydroxide (P < 0.05). CONCLUSIONS: Calcium hydroxide was associated with significantly less cell viability when compared with EndoBinder and MTA. All materials had gelatinolytic activity for MMP-2 with calcium hydroxide being associated with the greatest activity.

Clinical effects of prolonged application time of an in-office bleaching gel.

OBJECTIVE: The aim of this study was to evaluate whether the use of a gel applied for 1 × 45 minutes would have the same bleaching rate and tooth sensitivity levels when compared with 3 × 15-minute applications. METHODS: In-office bleaching was performed in 30 participants with 35% hydrogen peroxide gel. In one group (n=15; 3 x 15 minutes), the bleaching agent was refreshed every 15 minutes, three times at each bleaching appointment. In the other group (n=15; 1 x 45 minutes) the gel was left undisturbed on the buccal surfaces of all teeth for 45 minutes at each bleaching appointment. This protocol was repeated after one week. The bleaching evaluation was completed by two blinded, calibrated evaluators who compared the baseline color of the maxillary anterior teeth with a value-oriented shade guide after each period. The patients recorded the tooth sensitivity on a 0-4 scale. The color changes were evaluated by appropriate tests (α=0.05). The percentage of patients with tooth sensitivity and its intensity were also statistically analyzed (α=0.05), respectively. RESULTS: The use of gel for a single 45-minute period (1 x 45 minutes) decreased the bleaching efficacy (p<0.05) 86.7%, and 100% of patients from the 3 × 15-minute and 1 × 45-minute groups, respectively, experienced tooth sensitivity (p=0.22). The intensity of sensitivity was lower for the 3 × 15-minute applications (p=0.04). CONCLUSIONS: A 35% hydrogen peroxide gel for in-office bleaching preferably should be applied in three 15-minute applications because 1 × 45 minutes reduces the bleaching speed and slightly increases the intensity of tooth sensitivity.