Effects of endodontic irrigation solutions on structural, chemical, and mechanical properties of coronal dentin: A scoping review.

OBJECTIVE: This review aims to assess structural, chemical, and mechanical properties of coronal dentin after endodontic irrigation. MATERIALS AND METHODS: Reporting followed the PRISMA extension for scoping reviews. An electronic search was carried out in PubMed, Embase, and Cochrane Library. Records filtered by language and published up to November 4, 2022 were independently screened by two researchers. Studies evaluating structural, chemical, or mechanical properties of human permanent coronal dentin after irrigation within the scope of nonsurgical root canal treatment were included. Data were extracted regarding study type, sample description and size, experimental groups, outcome, evaluation method, and main findings. RESULTS: From the initial 1916 studies, and by adding 2 cross-references, 11 in vitro studies were included. Seven studies provide ultrastructural and/or chemical characterization, and six assessed microhardness and/or flexural strength. One percent to 8% sodium hypochlorite (NaOCl) and 1%-17% ethylenediaminetetraacetic acid (EDTA) were the most commonly tested solutions, with contact times of 2-240 min (NaOCl) and 1-1440 min (EDTA) being evaluated. CONCLUSIONS: Overall, the literature is consensual regarding the inevitable impact of NaOCl and chelating agents on coronal dentin, with both deproteinizing and decalcifying effects being concentration- and time-dependent. The alteration of mechanical parameters further confirmed the surface and subsurface ultrastructural and chemical changes. CLINICAL SIGNIFICANCE: Endodontic treatment success highly depends on restorative sealing. Understanding the result of exposing coronal dentin, the main substrate for bonding, to irrigants' action is crucial. The deproteinizing and decalcifying effects of NaOCl and chelating agents are both concentration- and time-dependent, causing surface and subsurface ultrastructural, chemical, and mechanical alterations.

Effect of Different Irrigants on the Adhesive Interface and Influence on the Push Out Strength of Fiber Posts.

PURPOSE: The aim of this study was to evaluate the effects of a new irrigant solution on the post space cleaning and the adhesive resistance of fiber posts. METHODS AND MATERIALS: Eighty roots of bovine teeth were randomly allocated into eight groups (n=10 for each group). Evaluations were performed in two different time points for each irrigant. The irrigants included a control group with distilled water (DW), 2.5% NaOCl and 17% EDTA (SH), 1% peracetic acid (PA), and 5% boric acid and 1% citric acid (EX). The time points were 24 hours (I-immediate) and 6 months (D-delayed). The push-out test was performed using a universal testing machine with a 5 kN load cell operating at a crosshead speed of 0.5 mm/minute. The dentinal cementation system was analyzed using a laser confocal microscope (LSM5, Zeiss, Jena, Germany), and incidence of residue on radicular dentin was evaluated by scanning electron microscopy (SEM). The incidence of residue was evaluated by the Kruskal-Wallis test and push-out bond strength and dentin penetrability were evaluated via a one-way analysis of variance (ANOVA) and Tukey tests (α=0.05). RESULTS: The EX irrigation protocol demonstrated the lowest incidence of residue on the dentin surface (p<0.05), independently of the evaluated third. In the cervical and the middle post thirds, EXI, EXD, SHI, and SHD groups exhibited similar push-out bond strength values (p>0.05). EXI, EXD, PAI, and PAD exhibited the greatest dentinal penetrability of the cementation system in all the post thirds (p<0.05). CONCLUSIONS: A solution containing 5% boric acid and 1% citric acid can be a promising irrigant for radicular post space cleaning. It has adequate potential for cleaning the dentin surface without interfering with the adhesive interface between the dentin and the cementation system.

Uso do endoactivator no tratamento endodôntico / Use of the endoactivator in endodontic treatment

Introdução: a irrigação é uma das etapas essenciais no preparo biomecânico e, buscando aumentar a eficiência desta, novos métodos vem sendo empregados no intuito de melhorar a ação e o alcance das soluções irrigadoras. Objetivo: analisar a eficácia do sistema EndoActivator em várias etapas do tratamento endodôntico. Resultados e discussão: apesar de diferenças de metodologias na literatura, o EndoActivator apresentou bons resultados em comparação com a irrigação convencional quando empregado em diferentes fases do tratamento endodôntico. Conclusão: o sistema EndoActivator é seguro e eficaz durante o preparo biomecânico, porém, assim como outros dispositivos de agitação mecânica da solução irrigante, não é capaz de promover completa limpeza dos canais radiculares.

Introduction: the irrigation is an essential part of biomechanical preparation and seeking increase the efficiency of this, new methods have been used in order to expand the effect of irrigating solutions, and promote the reach for areas with difficult access. Objective: the objective of this literature review was to analyze the effectiveness of the EndoActivator system in several stages of endodontic treatment. Results and Discussion: despite differences in methodologies in the literature, the EndoActivator presented good results in comparison to conventional irrigation when used in different phases of endodontic treatment. Conclusion: the EndoActivator system is safe and effective during biomechanical preparation, but, like other mechanical agitation devices of the irrigating solution, it is not able to promote complete cleaning to root canals.

Pulpotomy Medicaments used in Deciduous Dentition: An Update.

The aim of this paper was to review the history and the scientific literature published on pulpotomy medicaments and to present the findings of these studies. The review showed that pulpotomy of primary teeth has been treated with many different techniques and medicaments, that some of these approaches are controversial and that their results have presented variables of success rates in term of clinical, radiographic and histologic observation. It is important that all clinicians, particularly for pediatric dentists, be up to date with the recent trends in this area of dental treatment for children.

Available chlorine consumption from NaOCl solutions passively placed in instrumented human root canals.

AIM: To monitor chlorine consumption from nonagitated aqueous sodium hypochlorite (NaOCl) solutions in human root canals using a recently developed assay, which can determine the order of magnitude of available chlorine in small volumes of liquid. METHODOLOGY: The root canals of 80 extracted single-rooted human teeth were instrumented to ProTaper Universal F4 and irrigated using 1% NaOCl. Subsequently, canals were irrigated with copious amounts of deionized water to rinse out the residual chlorine. Subsequently, the teeth were sealed externally and placed in a water bath of 37 °C. Root canals were filled with NaOCl of 1%, 2.75%, 5.5%, or distilled water for 1, 10, 100 or 1000 min (n = 5 teeth per solution and time). Consumption of chlorine was measured using paper points pre-impregnated with 15% potassium iodide. Colour change of the paper points was determined photo-electronically, assessing their red value after absorbing solutions from root canals. Measurements were compared to a standard series of NaOCl down to 0.001% (n = 5 paper points per concentration). RESULTS: Red values of the paper points inserted into the root canal were affected by initial NaOCl concentration and time (two-way anova, P < 0.05). If NaOCl concentrations above 0.1% are considered to be clinically relevant, then 5.5% NaOCl retained its activity in the root canal for more than 100 min, whereas 1% NaOCl lost its activity between 10 and 100 min. CONCLUSIONS: Nonagitated NaOCl solutions can remain biologically active in human root canals for extended time periods.

Quantitative assessment of root canal roughness with calcium-based hypochlorite irrigants by 3D CLSM.

Chemical solutions play important roles in endodontic treatment and promote ultrastructural changes in dentin surface. The aim of this study was to quantify root canal roughness at different concentrations of calcium hypochlorite (Ca(OCl)2) and sodium hypochlorite (NaOCl) by confocal laser scanning microscopy (CLSM). Fifty-two human mandibular premolars were sectioned and randomly organized into thirteen groups (n=8): saline (control); 1%, 2.5% and 5% NaOCl; 1%, 2.5% and 5% Ca(OCl)2; the hypochlorite groups were further divided into with or without EDTA. The chlorine concentrations of the different solutions were measured by iodine titration (%). The superficial roughness (Sa) was quantified by CLSM. Ca(OCl)2 presented substantial decrease in chlorine concentration that differed from the package indication, but without compromising the dentin ultrastructure changes. There were no significant differences in dentin roughness between Ca(OCl)2 or NaOCl at all studied concentrations. The combination with EDTA provided similar roughness values among the solutions (p>0.05). The 5% Ca(OCl)2 and NaOCl solutions significantly increased dentin roughness and did not differ from the EDTA association (p>0.05). Ca(OCl)2 promoted similar dentin roughness as the NaOCl at the same concentrations and combined with EDTA. It may be concluded that Ca(OCl)2 modified the root canal dentin roughness similarly to NaOCl, at the same concentrations and EDTA combinations used in this study. Ca(OCl)2 and NaOCl, both at 5%, significantly altered dentin roughness, overcoming EDTA association, thus Ca(OCl)2 concentrations ranging from 1% to 2.5% may be suitable solutions for root canal irrigation protocols.

An evaluation of the accuracy of labeling of percent sodium hypochlorite on various commercial and professional sources: is sodium hypochlorite from these sources equally suitable for endodontic irrigation?

INTRODUCTION: The shelf life of sodium hypochlorite (NaOCl) is limited, and a previous article showed that there can be a discrepancy between the expected concentration of free available chlorine (FAC) and the actual FAC concentration in NaOCl solutions intended for endodontic irrigation. The current study investigates the FAC content of domestic and professional NaOCls and evaluates the influences of dilution and storage on FAC concentration. METHODS: First, domestic and professional NaOCls not obtained from manufacturers were iodometrically titrated. Then, NaOCls were diluted with demineralized water or tap water and stored at 4°C or 18°C and analyzed at baseline and 2 and 22 weeks. Statistical analyses included paired samples, independent samples t tests and repeated multivariate analysis of variance. Correlations were calculated with the Pearson or Spearman rank correlation test. A P < .05 was considered significant. RESULTS: Label specifications of domestic NaOCl were very imprecise (ie, <5% NaOCl). Domestic NaOCl contained 1.8%-3.5% NaOCl (w/v). Professional NaOCl varied from 14.3% relative less FAC than specified on the label to 23.5% relative more FAC than specified. After 22 weeks, the relative average loss of FAC in all conditions was 5.4% FAC (P = .002). Dilution, diluents, or storage temperature had no effect on the decline of FAC caused by aging. CONCLUSIONS: There is a great variation in NaOCl concentrations, with domestic NaOCl being the least accurate. NaOCl can be stored up to 5 months. The FAC concentration of domestic NaOCl is unpredictable, and, therefore, it appears less suitable for clinical application as root canal irrigant.

Spectrophotometric determination of irrigant extrusion using passive ultrasonic irrigation, EndoActivator, or syringe irrigation.

INTRODUCTION: Sodium hypochlorite (NaOCl) irrigation is critical to endodontic success, and several new methods have been developed to improve irrigation efficacy (eg, passive ultrasonic irrigation [PUI] and EndoActivator [EA]). Using a novel spectrophotometric method, this study evaluated NaOCl irrigant extrusion during canal irrigation. METHODS: One hundred fourteen single-rooted extracted teeth were decoronated to leave 15 mm of the root length for each tooth. Cleaning and shaping of the teeth were completed using standardized hand and rotary instrumentation to an apical file size #40/0.04 taper. Roots were sealed (not apex), and 54 straight roots (n = 18/group) and 60 curved roots (>20° curvature, n = 20/group) were included. Teeth were irrigated with 5.25% NaOCl by 1 of 3 methods: passive irrigation with needle, PUI, or EA irrigation. Extrusion of NaOCl was evaluated using a pH indicator and a spectrophotometer. Standard curves were prepared with known amounts of irrigant to quantify amounts in unknown samples. RESULTS: Irrigant extrusion was minimal with all methods, with most teeth showing no NaOCl extrusion in straight or curved roots. Minor NaOCl extrusion (1-3 µL) in straight roots or curved roots occurred in 10%-11% of teeth in all 3 irrigant methods. Two teeth in both the syringe irrigation and the EA group extruded 3-10 µL of NaOCl. CONCLUSIONS: The spectrophotometric method used in this study proved to be very sensitive while providing quantification of the irrigant levels extruded. Using the PUI or EA tip to within 1 mm of the working length appears to be fairly safe, but apical anatomy can vary in teeth to allow extrusion of irrigant.

Efficacy of ethylene-diamine-tetra-acetic acid associated with chlorhexidine on intracanal medication removal: a scanning electron microscopy study.

The aim of this study was to evaluate the effectiveness of 17% ethylene-diamine-tetra-acetic acid (EDTA) used alone or associated with 2% chlorhexidine gel (CHX) on intracanal medications (ICM) removal. Sixty single-rooted human teeth with fully formed apex were selected. The cervical and middle thirds of each canal were prepared with Gates Glidden drills and rotary files. The apical third was shaped with hand files. The specimens were randomly divided into two groups depending on the ICM used after instrumentation: calcium hydroxide Ca(OH)(2) +CHX or Ca(OH)(2) +sterile saline (SS). After seven days, each group was divided into subgroups according to the protocol used for ICM removal: instrumentation and irrigation either with EDTA, CHX+EDTA, or SS (control groups). All specimens were sectioned and processed for observation of the apical thirds by using scanning electron microscopy. Two calibrated evaluators attributed scores to each specimen. The differences between the protocols for ICM removal were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between the score of debris obtained in each root canal third. Remains of Ca(OH)(2) were found in all specimens independently of the protocol and ICM used (P > 0.05). Seventeen percent EDTA showed the best results in removing ICM when used alone (P < 0.05), particularly in those associated with CHX. It was concluded that the chelating agent 17% EDTA significantly improved the removal of ICM when used alone. Furthermore, the type of the vehicle associated with Ca(OH)(2) also plays a role in the ICM removal.

Determination of chemical components derived from 2% chlorhexidine gel degradation using gas chromatography-mass spectrometry.

OBJECTIVE: This study determined the chemical components derived from degradation of 2% chlorhexidine (CHX) gel and solution by using gas chromatography-mass spectrometry. MATERIALS AND METHODS: Three 2% CHX gels were used to identify the products of CHX gel degradation using gas chromatography-mass spectrometry. A solution of CHX was also evaluated to compare the degradation between gel and solution. Degradation was evaluated in four storage situations (on the worktable with light: on the worktable without light; in the Pasteur oven at 36.5°C without light; and in the refrigerator at 8°C without light). Measurements were made at four time points: initial analysis and 1, 3 and 6 months after. The conversion of CHX into para-chloroaniline in storage situations and in different periods was analyzed statistically using chi-square test (α = 5%). RESULTS: The 2% CHX gel or solution had already degraded vial found within the period of validity, at all time points and for all storage conditions. The amount of para-chloroaniline (pCA) was directly proportional to time in the case of CHX solution, but not in CHX gel due to lack of homogeneity. CHX homogeneity in hydroxyethylcellulose gel was directly dependent on compounding mode. CONCLUSIONS: Degradation products, such as para-chloroaniline (pCA), orto- chloroaniline (oCA), meta-chloroaniline (mCA), reactive oxygen species (ROS) and organochlorines (ortho-chlorophenyl isocyanate and 2-amino-5-clorobenzonitrila) were found in 2% CHX gel and solution, regardless of storage conditions or time. In relationship to gel homogenization an alternative to produce 2% CHX gel and a new homogenization method have been developed.

A new method to assess available chlorine in small volumes of liquid.

INTRODUCTION: There is no robust and simple way to quantify available chlorine from small volumes such as human root canals. Therefore, a new method was developed and assessed. METHODS: Standardized size-40 paper points were soaked in a 15% (w/v) potassium iodide solution for 1 minute. Subsequently, the paper points were placed in an incubator and dried at 110°C for 4 hours. The paper points (n = 5 per measurement) were then dipped in different concentrations of NaOCl and photographed under standardized conditions in RAW format. The pictures were imported to image processing software and adjusted to the standardized background. The red, green, and blue levels of the paper points were assessed at a predefined area. Inverse regression was used to determine NaOCl concentration from red, green, and blue values, with both explanatory and outcome variables log-transformed to base 10. RESULTS: The red value measurements were chosen for further analysis based on a comparison of the coefficient of determination (R(2)) and a residual analysis. The method was applied to concentrations of NaOCl between 0.0001% and 1% (R(2) = 0.92). In this range, NaOCI concentrations could be assessed with an error not larger than 3-fold the determined concentration. CONCLUSIONS: The present method proved to be robust to determine the order of magnitude of available chlorine that is present in a small volume. This should be useful for endodontic research.

Quantitative evaluation of apical extrusion of debris and irrigants using four rotary instrumentation systems: an in vitro study.

CLINICAL SIGNIFICANCE: The apical extrusion of infected debris may have the potential to disrupt the balance between microbial aggression and host defense, resulting in incidents of acute inflammation. During preparation, irrigants and debris, such as bacteria, dentin filings and necrotic tissue may be extruded into the periradicular region leading to periapical inflammation and postoperative flare ups. Using an instrumentation technique that minimizes apical extrusion would be beneficial to both the practitioner and patient. The purpose of the study was to evaluate the weight of debris and volume of irrigant extruded apically from extracted teeth in vitro after endodontic instrumentation using four different rotary root canal instrumentation systems. MATERIALS AND METHODS: Four groups of each 20 extracted mandibular premolars were instrumented using one of the four systems: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland)), Hero-shaper (MicroMega, Besancon, France), RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) and K3 (SybronEndo, West Collins, CA). Debris and irrigant extruded from the apical foramen during instrumentation were collected in preweighed test tubes. Volume of irrigant extruded was noted. The containers were stored in incubator at 70° for two days to evaporate the moisture. Weight of dry debris was noted. STATISTICAL ANALYSIS: Data was analyzed using Kruskall-Wallis and Mann-Whitney U test at a significance of 0.001. RESULTS: The results indicated that all of the instrumentation systems tested caused measurable apical extrusion of debris and irrigants. Higher extrusion was observed with Protaper system which was statistically significant with Hero-Shaper, RaCe and K3 systems. There were no statistical differences between Hero-shaper, K3 and RaCe systems (p < 0.05). CONCLUSION: All instrumentation techniques apically extruded debris and irrigant. However, Hero-shaper, K3 and RaCe systems produced less extruded debris and irrigant than the Protaper system.

Evaluation of chlorhexidine substantivity on human dentin: a chemical analysis.

INTRODUCTION: The aim of this study was to investigate the substantivity of chlorhexidine (CHX) solution and gel within a root canal system for 24 hours, 30 days, and 90 days. METHODS: Forty-five extracted human anterior teeth were used for this study. The samples were divided into 3 groups according to the chemical auxiliary substance used to perform the root canal preparation: group 1, 2% liquid CHX; group 2, 2% gel CHX; and group 3, distilled water (the control group). The working length was determined by inserting a #10 K-file into the canal up to the moment its tip was seen in the apex foramen and then withdrawing it 1 mm. The roots were prepared up to the instrument #45. Longitudinal grooves were carved on the free surfaces of the roots, providing 2 halves of each root and resulting in 30 samples per group. Each group was randomly divided into 3 subgroups (n = 10), and substantivity was evaluated after 24 hours, 30 days, and 90 days of incubation. The amount of CHX (in micrometers) was measured through reverse-phase high-performance liquid chromatography. Statistical analysis was performed by analysis of variance and the Tukey test for post hoc comparisons (α = 0.05). RESULTS: The control group showed no substantivity. Significant amounts of CHX solution and gel remained retained in dentin substrates independent of the time of incubation (P < .05). CHX solution showed a higher substantivity than CHX gel, with the exception of groups incubated for 90 days. The decreasing amounts of retained CHX inside the canal were for 24 hours >30 days >90 days for CHX solution and 24 hours >30 days ≥ 90 days for CHX gel. CONCLUSIONS: The results of this study indicate that CHX solution and gel are retained in root canal dentin for up to 90 days.

The effect of surfactant on the dissolution of porcine pulpal tissue by sodium hypochlorite solutions.

INTRODUCTION: A previous study of the relative dental pulp-dissolving abilities of Milton brand of sodium hypochlorite (NaOCl) and other surfactant-containing NaOCl solutions produced specifically for endodontic treatment showed a markedly better performance of the surfactant-containing product that was not explained by differences in active chlorine content. This study investigated whether the presence of surfactant in the NaOCl solutions was responsible for the difference in dissolution times seen in the previous study. METHODS: Circular samples 2.5 mm in diameter were punched out of the pulps of mandibular incisor teeth from young pigs. The 4 NaOCl solutions tested were Hypochlor 1% and Hypochlor 4% forte, which contained surfactant, and 2 identical solutions without surfactant. Twenty pulp specimens were immersed in 20 individual 25-mL aliquots of each of the 4 NaOCl solutions and observed while stirring until dissolution was complete. The time to dissolution of each sample was determined by stopwatch. Dissolution times for each solution were averaged and compared statistically in R (version 2.12.0) by using multiple regression with nominal active chlorine content as a covariate. RESULTS: No statistical difference was detected between the dissolution times for either of the Hypochlor solutions with and without surfactant. CONCLUSIONS: The addition of surfactant alone does not appear to improve the abilities of NaOCl to dissolve dental pulp tissue.

Efeitos do hidróxido de cálcio e da clorexidina sobre a expressão de citocinas em infecções endodônticas / Effects of calcium hydroxide and chlorhexidine on cytokine expression in endodontic infections

Introdução: A eliminação de microorganismos do sistema de canais radiculares infectados é uma etapa crucial que envolve o complexo debridamento mecânico-químico e a utilização de uma medicação intracanal. O hidróxido de cálcio vem sendo indicado nestes casos por ser estável por longos períodos, por possuir boa biocompatibilidade, ser bactericida em uma área limitada, além de induzir a formação de tecido mineralizado e ser efetivo contra a formação de exsudados inflamatórios. A Clorexidina (CHX) é uma molécula hidrofóbica e lipofílica positivamente carregada, que vem sendo utilizada como solução irrigadora e medicação intracanal...

The effect of calcium hydroxide on the steroid component of Ledermix and Odontopaste.

AIM: To investigate the chemical interaction of calcium hydroxide with the corticosteroid triamcinolone acetonide in Ledermix Paste and in Odontopaste, a new steroid/antibiotic paste. METHODOLOGY: Validated methods were developed to analyse the interaction of calcium hydroxide in two forms, Pulpdent Paste and calcium hydroxide powder, with triamcinolone acetonide within Odontopaste and Ledermix Paste. High-performance liquid chromatography (HPLC) was used to analyse the mixed samples of the pastes and calcium hydroxide. The concentration of triamcinolone acetonide within the pastes was determined over 0, 2, 6, 24 and 72-h time-points. All tests with the HPLC involved the testing of the standard with triplicate injections alongside the samples. All samples were tested in duplicate with each injected twice; therefore, four tests were performed for each investigation. Linearity, precision and specificity of the testing procedures and apparatus were validated. Descriptive statistics are provided. RESULTS: In both pastes, there was a marked rapid destruction of the triamcinolone acetonide steroid upon mixing with calcium hydroxide. Odontopaste suffered a lower rate of destruction of the triamcinolone acetonide component than Ledermix Paste, but both pastes showed very similar degrees of steroid destruction after 72 h. When using calcium hydroxide powder with Ledermix Paste, the triamcinolone was destroyed entirely and immediately. CONCLUSION: The addition of calcium hydroxide to Odontopaste or Ledermix Paste results in the rapid destruction of the steroid.

Evaluation of pH, available chlorine content, and antibacterial activity of endodontic irrigants and their combinations against Enterococcus faecalis.

OBJECTIVES: The objectives of this study were to evaluate pH, available chlorine content, and antibacterial activity of endodontic irrigants and their combinations. STUDY DESIGN: The pH and chlorine content of sodium hypochlorite (NaOCl) were analyzed pure and in combination with 10% citric acid (CA) and apple vinegar (AV). The antibacterial effect of the following solutions was measured by direct contact test against Enterococcus faecalis: 2.5% NaOCl, 2.5% NaOCl +10% CA (7:3), 2.5% NaOCl + AV (5:5), 10% CA, and AV. Sterile saline was used as control. The colony-forming units were determined by serial decimal dilutions. RESULTS: The combination of 2.5% NaOCl with CA or AV lowered the pH and the chlorine content. NaOCl, alone or in combination was able to eliminate E. faecalis in 30 seconds, and CA, after 10 minutes. AV promoted reduction (32.2%) after 10 minutes. CONCLUSIONS: NaOCl with acidic solutions lowered the pH and the chlorine content, but did not alter its antibacterial effect.

Influence of ethylenediaminetetraacetic acid on the active chlorine content of sodium hypochlorite solutions when mixed in various proportions.

INTRODUCTION: This study documented the time-related effect on active chlorine content of NaOCl solutions of different concentrations after dilution with ethylenediaminetetraacetic acid (EDTA) in various proportions. METHODS: Five NaOCl solutions (Milton, Black and Gold domestic bleach, and the surfactant containing products, White King and Hypochlor 1% and 4% forte) were mixed with EDTA in the following proportions: 90:10, 75:25, and 50:50. Changes in active chlorine content were determined at intervals between 5 and 18 minutes. RESULTS: Results were analyzed statistically by using general linear statistical models in SPSS. With the exception of White King solutions, EDTA substantially and rapidly reduced available chlorine even in small proportions, with loss being extreme at first and then more gradual. The reaction was exothermic. Results showed that White King mixed 90:10 lost on average only 8% of its active chlorine at its first measurement (approximately 5 minutes) but lost 36% of its active chlorine when mixed 75:25. The Hypochlor products at 90:10 dilution lost on average 27%-31% active chlorine during this time period. Mixing EDTA with NaOCl caused a dramatic loss of active chlorine for all solutions mixed 50:50. NaOCl solutions containing surfactant had less active chlorine loss for the 75:25 and 90:10 admixtures. CONCLUSIONS: NaOCl and EDTA should not be present in the root canal at the same time if the therapeutic benefits of NaOCl are to be realized, but the order in which they should be used for endodontic irrigation remains a matter of debate.

Utilização dos lasers de Er:YAG e Nd:YAG na desinfecção do sistema de canais radiculares: revisão de literatura / Use of Er:YAG and Nd:YAG lasers in the desinfection of root canals system: a literature review

A sanificação do sistema de canais radiculares cujo objetivo é promover a eliminação de microrganismos é considerada um dos principais objetivos e determinantes para o sucesso da terapia endodôntica. Neste sentido, novos instrumentos, equipamentos e materiais estão constantemente sendo desenvolvidos, destacando-se os aparelhos de Lasers que podem ser utilizados em vários procedimentos odontológicos. O objetivo deste artigo foi esclarecer aos clínicos e especialistas, através de uma revisão de literatura sobre a utilização dos lasers de Er:YAG e Nd:YAG na eliminação dos microrganismos que colonizamo sistema de canais radiculares.

Capacidade seladora do agregado de trióxido mineral em perfurações de furca após irrigação final com diferentes soluções / Mineral trioxide aggregate sealing ability in furcal perforations after final irrigation with different solutions

Introdução - O presente estudo avaliou a influência de diferentes soluções irrigadoras na capacidade seladora do MTA quando utilizado em perfurações na região de furca de molares inferiores extraídos. Material e Métodos - Trinta molares inferiores humanos foram submetidos à abertura endodôntica convencional e tiveram o centro do assoalho perfurado propositalmente com broca esférica diamantada. Os espécimes foram divididos em 3 grupos (n = 10) de acordo com as soluções utilizadas: G1-soro fisiológico; G2-NaOCl a 1% e G3-EDTA 17%. Foi realizado o preenchimento da perfuração com MTA Angelus cinza e o selamento coronário provisório. Em seguida,realizou-se a impermeabilização da superfície externa, exceto na região de furca, e imersão em corante nanquim por 72 horas. A mensuração, em milímetros, da infiltração linear foi realizada por meio do software Image Tool. Resultados - Os resultados demonstraram que a solução de EDTA 17% permitiu menor infiltração, sendo estatisticamente diferente do NaOCl a 1% e do soro fisiológico(p < 0,05). Conclusão - De acordo com os resultados, pode-se concluir que a solução de EDTA parece ser a melhor escolha para irrigação final em casos de perfuração de furca.

Introduction - This study assessed the influence of different final irrigation on the sealing ability of MTA-Angelus in furcal perforations of extracted human molar teeth. Material and Methods - Thirty human mandibular molars were conventionally accessed and perforations were purposely created in the center of the pulp chamber floor by using a round diamond bur. The specimens were divided into 3 groups (n = 10) according to the irrigation: G1-saline solution; G2-1% sodium hypochlorite; G3-17% EDTA. Teeth were repaired with Angelus'gray MTA and the crowns were sealed.Then the impermeabilization of the external surface was made except in the furcal region, and they were immersed into Indian Ink for 72 hours. The leakage was measured, in millimeters, by Image Tool software. Results - The results showed lower leakage index for EDTA group that was statistically different from 1% NaOCl and saline solution groups (p < 0.05). Conclusion - According to results it can be concluded that in cases of furcal perforation EDTA solution seems to be the best choice of final irrigation.