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.

Efectividad de distintas técnicas de activación en la remoción de medicación de hidróxido de calcio de las paredes radiculares / Effectiveness of different activation techniques in the removal of calcium hydroxide medication from root canal walls

Objetivos: Investigar distintos protocolos de irrigación y soluciones para la remoción de hidróxido de calcio de las paredes radiculares mediante Microscopía Electrónica de Barrido (MEB). Metodología: Se seleccionó una muestra de 48 raíces palatinas de molares superiores. Los conductos fueron instrumentados, irrigados, secados y obturados con medicación a base de hidróxido de calcio. Los dientes fueron aleatoriamente asignados en 6 grupos, dependiendo de la técnica utilizada para activar hipoclorito sódico y Smear Clear para la remoción de la medicación intraconducto: Grupo 1, Irrigación positiva con jeringa (P), Grupo 2, Irrigación Ultrasónica (UI), Grupo 3, Irrigación por presión apical negativa (ANP), Grupo 4: Irrigación ultrasónica pasiva e irrigación por presión apical negativa (UI + ANP). Se incluyeron dos grupos control: Grupo 5: Grupo control positivo (C+), que fue obturado con hidróxido de calcio, pero no se eliminó del conducto, y Grupo 6: Grupo control negativo (C-), que no fue obturado con hidróxido de calcio. Todos los conductos fueron observados con microscopio electrónica de barrido (MEB). Se evaluó la presencia de material residual usando un sistema de medición en los tercios apical, medio y coronal. Los resultados fueron analizados estadísticamente mediante los test de Kruskal-Wallis y Bonferroni (p < 0,05). Resultados: Se encontraron diferencias estadísticamente significativas entre todos los grupos en todos los tercios a estudio (p < 0,05). El uso combinado de UI y ANP resultó en una remoción más eficiente de hidróxido de calcio de las paredes radiculares, independientemente del área analizada. Conclusiones: La utilización de irrigación ultrasónica pasiva e irrigación por presión apical negativa como activación final, sugiere una mejor limpieza de los conductos. Ninguna técnica es capaz de remover completamente el hidróxido de calcio de las paredes radiculares

Aim: To investigate different irrigation protocols and solutions to remove Ca(OH)2 from the root canal walls by using Scanning Electron Microscopy (SEM). Methodology. Forty-eight palatal roots from upper molars were selected. The root canals were instrumented, irrigated, dried and filled with a calcium hydroxide medication. Teeth were then randomly assigned to one of 6 groups depending on which technique was used to activate NaOCl and Smear Clear irrigants to remove medication: Group 1, Positive syringe irrigation (P); Group 2, Ultrasonic Irrigation (UI); Group 3, Apical Negative Pressure irrigation (ANP); Group 4, Passive Ultrasonic Irrigation and Apical Negative Pressure irrigation (UI + ANP). 2 control groups were also included: Group 5, positive control (C+), which were filled with calcium hydroxide that was not removed from the canal and Group 6, negative controls (C-), which were not filled with calcium hydroxide. All root canals were observed through SEM. Presence of residual material was evaluated using a score system for the coronal, middle, and apical portions. Data were statistically analysed using the Kruskal-Wallis and Bonferroni tests (P < 0.05). Results. There was a statistically significant difference among all groups at all root levels (P < 0.05). The combined use of UI and ANP irrigation resulted more efficient in the removal of calcium hydroxide from the root canal walls, irrespective of the area analyzed. Conclusions. The use of passive ultrasonic irrigation and apical negative pressure as a final activation is suggested to improve cleaning of the root canals. No technique is able to completely remove calcium hydroxide dressing from the root canal walls

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.

Sistemas ultrasónicos para la irrigación del sistema de conductos radiculares / Ultrasonic devices for root canal system irrigation

La eliminación de los restos de tejido pulpar vital y necrótico y de los microorganismos del sistema de conductos radiculares, es esencial para el éxito en endodoncia. La desinfección del canal radicular mediante la irrigación e instrumentación es el factor más importante en la prevención y tratamiento de la periodontitis apical. Al ser imposible con la instrumentación llegar a todas las áreas del sistema de conductos, la irrigación cobra especial importancia. Por este motivo, en la última década se han desarrollado una serie de sistemas de dispensación y agitación de irrigantes, tales como los ultrasonidos. En concreto, en este artículo de revisión se evalúa la información disponible de los diez últimos años sobre la efectividad de los sistemas ultrasónicos para eliminar bacterias, tejido pulpar, restos de dentina y barrillo dentinario, la capacidad de estos dispositivos para hacer que el irrigante penetre en el sistema de conductos radiculares y la seguridad en su uso. Los resultados de la revisión muestran que los sistemas ultrasónicos son más eficaces en el desbridamiento químico, biológico y físico del sistema de conductos radiculares que los sistemas de irrigación convencional, a la vez que son seguros (AU)

Removal of vital and necrotic remnants of pulp tissues and microorganisms from the root canal system is essential for endodontic success. Disinfection of the root canal by irrigation and instrumentation are the most important factors in the prevention and treatment of apical periodontitis. As it is impossible for the instruments to reach all the areas of the root canal system, the irrigation has gained special importance. Due to this fact, technological advances during the last decade have brought new delivery and agitation devices, such as ultrasonic devices. Particularly, this review article assesses the available information from the last ten years about the effectiveness of ultrasonic devices to remove bacteria, pulp tissue, dentin debris and smear layer, and the ability of these devices to make the irrigant solution penetrate into the root canal system and the safety of its use. Nowadays scientific literature reveals that ultrasonic devices are more effective on chemical, biological and physical debridement of the root canal system than conventional technique and being safety devices at the same time (AU)

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.

Interferometric microscopy study of the surface roughness of Portland cement under the action of different irrigants

OBJECTIVES: Some investigations suggested common Portland cement (PC) as a substitute material for MTA for endodontic use; both MTA and PC have a similar composition. The aim of this study was to determine the surface roughness of common PC before and after the exposition to different endodontic irrigating solutions: 10% and 20% citric acid, 17% ethylenediaminetetraacetic (EDTA) and 5% sodium hypochlorite. Study design: Fifty PC samples in the form of cubes were prepared. PC was mixed with distilled water (powder/liquid ratio 3:1 by weight). The samples were immersed for one minute in 10% and 20% citric acid, 17% EDTA and 5% sodium hypochlorite. After gold coating, PC samples were examined using the New View 100 Zygo interferometric microscope. It was used to examine and register the surface roughness and the profile of two different areas of each sample. Analysis of variance (ANOVA) was carried out, and as the requirements were not met, use was made of the Kruskal-Wallis test for analysis of the results obtained, followed by contrasts using Tukey's contrast tests. RESULTS: Sodium hypochlorite at a concentration of 5% significantly reduced the surface roughness of PC, while 20% citric acid significantly increased surface roughness. The other evaluated citric acid concentration (10%) slightly increased the surface roughness of PC, though statistical significance was not reached. EDTA at a concentration of 17% failed to modify PC surface roughness. Irrigation with 5% sodium hypochlorite and 20% citric acid lowered and raised the roughness values, respectively. CONCLUSIONS: The surface texture of PC is modified as the result of treatment with different irrigating solutions commonly used in endodontics, depending on their chemical composition and concentration

Actualización en endodoncia 2012 / 2012 Update in endodontics

Los autores revisan los artículos publicados en las revistas científicas más significativas en el ámbito de la endodoncia durante el año 2012, comparándolos entre ellos, con otros anteriores y con los conceptos clásicos de la endodoncia (AU)

The authors review the articles published in the most relevant journals concerning endodontics during the last year 2012, making a comparison between them, as well as with other older ones and with classic concepts in endodontics (AU)

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.

Review of ultrasonic irrigation in endodontics: increasing action of irrigating solutions

Introduction: Effective irrigant delivery and agitation are prerequisites for successful endodontic treatment. Ultrasonic irrigation can be performed with or without simultaneous ultrasonic instrumentation. Existing literature reveals that ultrasonic irrigation may have a very positive effect on chemical, biological and physical debridement of the root canal system as investigated in many in vitro studies.Objective: The purpose of this review article was to summarize and discuss the available information concerning ultrasonic irrigation in endodontics. Methods: This article presents an overview of ultrasonic irrigation methods and their debridement efficacy. In this paper the relevant literature on passive ultrasonic irrigation is reviewed. Information from original scientific papers or reviews listed in MEDLINE and Cochrane were included in the review. Results: The use of ultrasound in the irrigation procedure results in improved canal cleanliness, better irrigant transfer to the canal system, soft tissue debridement, and removal of smear layer and bacteria. There are many in vitro studies, but there is a need to standardize protocols, and correlate the clinical efficacy of ultrasonic devices with improved treatment outcomes. Understanding the basis of ultrasonic irrigation is fundamental for clinicians and researchers to improve the design and use of ultrasonic irrigation (AU)

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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...