Chitosan: A natural substitute of EDTA solution for final irrigation in endodontics treatment.

BACKGROUND: The purpose of this study was to assess the quantity of the chelated calcium ions and the smear layer removal efficiency after root canal final irrigation with three different solutions. MATERIALS AND METHODS: Forty-five teeth were instrumented with rotary-files, then randomly divided into 3 equal groups (n = 15) depending on the final irrigation solution; group I: 17% ethylenediaminetetraacetic acid (EDTA), group II: 0.2% chitosan, and group III: 10% trisodium citrate. According to the time of application, every group was divided into 3 subgroups (1 min, 5 min, and 24 h). The quantification analysis of chelated calcium ions was performed by flame atomic absorption spectrometry (FAAS). Then, the presence of smear layer was examined by splitting the samples longitudinally and using scanning electron microscopy (SEM) to examine coronal, middle, and apical root canal levels. One-way analysis of variance (ANOVA) test was used for the evaluation of treatment effect. Kruskal-Wallis test was executed to detect a significant difference between groups, while Mann-Whitney U test has determined the difference between each two groups for smear layer. RESULTS: Both 17% EDTA and 0.2% chitosan had not been statistically significant difference for smear layer removal efficiency and observed calcium ion concentrations. Although, they were more efficient of 10% trisodium citrate with a significant difference (P < 0.05). CONCLUSION: The application time of the chelators' solutions must not exceed 5 min to completely remove smear layer, and 0.2% chitosan is a natural substitute for 17% EDTA with a safety application for 24 h.

A comparative scanning electron microscopy evaluation of smear layer removal with chitosan and MTAD.

The aim of the present study was to compare the efficacy of chitosan and MTAD for the smear layer removal from the root canal through a scanning electron microscope (SEM). Thirty teeth were randomly divided into three groups according to the final irrigants: 0.2% chitosan, MTAD, saline (control group). After the mechanical preparation, the samples were irrigated with saline (control group), 0.2% chitosan and MTDA respectively. Then, the samples were split and the smear layer at the apical, middle, and coronal thirds of each root canal was imaged using SEM. The statistical analysis was performed using the Kruskal-Wallis test and the Mann-Whitney U test (α = 5%). The difference between chitosan and MTDA was statistically significant in the apical region (p < 0.05), no significant difference was obtained in the coronal and middle regions in these two experiment groups (p > 0.05). The control group exhibited the lowest efficacy in smear layer removal in all regions. Thus, from the result of the present study, we may conclude that chitosan was more effective in smear layer removal than MTAD especially in the apical third. CONTEXT: Irrigation, which serves a variety of purposes including antibacterial action, tissue dissolution, cleaning and chelating, plays a centric role in the final success of root canal treatment. Thus, more and more attention has been put on the improvement and development of various irrigation techniques or systems. AIMS: The aim of the present study was to compare the efficacy of chitosan and MTAD for the smear layer removal from the root canal through scanning electron microscopy (SEM). SETTINGS AND DESIGN: Thirty single-canal premolars were instrumented with rotary-files and then, randomly assigned to test groups which were irrigated with chitosan and MTDA, and control group was treated with saline. Thereafter, the efficacy of smear layer removal was evaluated by SEM. MATERIALS AND METHODS: Thirty teeth were randomly divided into three groups according to the final irrigants: 0.2% chitosan, MTAD, saline (control group). After the mechanical preparation, the samples were irrigated with saline (control group), 0.2% chitosan and MTDA respectively. Then, the samples were split and the smear layer at the apical, middle, and coronal thirds of each root canal was imaged using SEM. STATISTICAL ANALYSIS USED: Kruskal-Walli test and Mann-Whitney U test Results: The difference between chitosan and MTDA was statistically significant in the apical regions (p < 0.05), no significant difference was obtained in the coronal and middle regions in these two experiment groups (p > 0.05). The control group exhibited the lowest efficacy in smear layer removal in all regions. CONCLUSION: Thus, from the result of present study, we may conclude that chitosan was more effective in smear layer removal than MTAD, especially in the apical third.

Effects of seven different irrigation techniques on debris and the smear layer: a scanning electron microscopy study.

AIM: Conventional manual irrigation with a syringe and needle remains widely accepted technique in the irrigation procedures. However, its flushing action has some limitations. Currently, several techniques and systems are available and reported to improve the insufficiency of syringe irrigation. The aim of this study was to evaluate the effectiveness of 7 different irrigation techniques compared to standard irrigation. MATERIALS AND METHODS: Straight roots from 80 extracted human maxillary central incisors were collected, and root canals were instrumented with K-files up to apical size 50. The teeth were randomly divided into 8 groups (n = 10), and final irrigation procedures were performed with 17% ethylenediaminetetraacetic acid and 5.25% NaOCl solutions using following irrigation agitation techniques: RinsEndo, EndoVac, Canal CleanMax, sonic, Canal Brush, NaviTip FX, manual dynamic irrigation, and conventional irrigation. The presence of debris and smear layer (SL) at coronal, middle, and apical thirds was evaluated by using a 5-grade scoring system with ×200 and ×1000 magnification, respectively. RESULTS: Concerning debris removal, the MM 1500 sonic group reduced apical debris significantly better than the other groups tested (P < 0.05). There was no significant difference among the tested groups (P > 0.05) related SL removal in all levels. CONCLUSIONS: MM 1500 scored best with debris removal; however, there was no significant reduction in the SL in apical third with any of the methods tested.

Comparative evaluation of shaping ability of two nickel-titanium rotary systems using cone beam computed tomography.

BACKGROUND: We evaluated and compared the effects of different NiTi rotary systems--ProTaper Next and New One Shape--on the volume of dentin removed, canal transportation, and canal curvature in extracted human teeth using CBCT scanning with different voxel sizes. METHODS: Fifty extracted human maxillary first molars with mesiobuccal canal curvature (25-35°) were used. Specimens were instrumented with the ProTaper Next or New One Shape. Pre- and post-instrumentation scans were performed to compare transportation at the levels of 2, 5, and 8 mm and volumes with two different voxel sizes (0.125-and 0.100-mm(3)) using 3D CBCT images. This study evaluated and compare the volume of dentin removed, canal transportation, and canal curvature. Differences according to instrumentation and voxel sizes were assessed using the Mann-Whitney U-test and the Wilcoxon signed-rank test. RESULTS: Significant differences were found between apical and coronal levels for both systems (p < 0.05) in canal transportation. In comparing the systems, similar values were found at each level, without significant difference (p > 0.05) in terms of canal curvature and volume. Voxel sizes did not affect the measurements on canal volume, curvature or transportation; no significant difference was found between the 0.100- and 0.125-mm(3) voxel sizes (p > 0.05). CONCLUSIONS: Both instrumentation systems produced similar canal transportation and volume changes. The two voxel resolutions also showed similar results, however a 0.125-mm(3) voxel size can be recommend for a flat panel CBCT scanner with lower exposure dose.

Comparison of smear layer removal using the Nd:YAG laser, ultrasound, ProTaper Universal system, and CanalBrush methods: an in vitro study.

INTRODUCTION: The aim of this study was to compare the efficacy of the Nd:YAG laser, ultrasound, the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland), and the CanalBrush (Coltene Whaledent, Langenau, Germany) methods for the removal of the smear layer from the apical third of root canals. METHODS: Fifty distal root canals from extracted human mandibular first molars were instrumented up to ProTaper Universal F5 and divided randomly into 5 groups (n = 10) according to the following final irrigation agitation techniques: no agitation (control), ProTaper Universal file, ultrasound, CanalBrush, and Nd:YAG laser. Specimens were observed under a scanning electron microscope. The presence of the smear layer was evaluated using a 3-grade scoring system. The data were analyzed with Cohen kappa, Kruskal-Wallis, and Mann-Whitney U tests. A level of significance of .05 was adopted. RESULTS: The ultrasound group performed significantly better than the rest of the groups; 56.6% of the specimens revealed no smear layer, 44.4% showed the presence of a moderate smear layer, and no heavy smear layers were observed. In the Nd:YAG laser group, 30% of the specimens presented with no smear layer, 70% showed the presence of a moderate smear layer, and no heavy smear layers were observed. In contrast, a heavy smear layer was observed on the surfaces of the root canals in the CanalBrush (23.4%), ProTaper Universal (13.4%), and control (86.6%) groups. Statistically significant differences were observed (P < .05). CONCLUSIONS: None of the agitation methods completely removed the smear layer. However, the ultrasound method performed significantly better followed by the Nd:YAG laser, the CanalBrush, and the ProTaper Universal system. Agitation of the irrigant improved smear layer removal in the apical third of the canal.

Phytic acid: an alternative root canal chelating agent.

INTRODUCTION: The objectives of this study were to investigate the effect of phytic acid, inositol hexakisphosphate (IP6), as a final rinse on the surface of instrumented root canals and smear-layered flat dentin surfaces treated with sodium hypochlorite (NaOCl) and to evaluate its effect on the viability and alkaline phosphatase activity of osteoblast-like cells (MC3T3-E1). METHODS: The universally accepted chelating agent EDTA was used as the control in all conducted experiments. Root canals of human canines were instrumented with rotary files and irrigated with 5% NaOCl, followed by a final rinse of 17% EDTA (1 minute), 1% IP6 (1 minute or 30 seconds), or distilled water. NaOCl-treated flat coronal dentin surfaces were also treated with 17% EDTA (1 minute), 1% IP6 (1 minute or 30 seconds), or distilled water. The presence or absence of smear layer was evaluated with scanning electron microscopy. Cell viability and alkaline phosphatase assays were performed to evaluate the effect of IP6 and EDTA on cultured MC3T3-E1 cells. RESULTS: The results demonstrated the ability of IP6 to remove the smear layer from instrumented root canals and flat coronal dentin surfaces. When compared with EDTA, IP6 was less cytotoxic and did not affect the differentiation of MC3T3-E1 cells. CONCLUSIONS: IP6 shows the potential to be an effective and biocompatible chelating agent.

Technical quality of root canal treatment of posterior teeth after rotary or hand preparation by fifth year undergraduate students, The University of Jordan.

The aim of this study was to investigate the technical quality of root canal treatment provided by the undergraduate students as their first experience in molar endodontics using nickel-titanium (NiTi) files in a crown-down approach compared with stainless steel standard technique. This study was carried out by the fifth year undergraduate students attending peer review sessions as a part of their training programme, using two different questionnaires to assess the overall technical quality and potential problems regarding endodontic complications after root canal preparation with these two techniques. The overall results indicated a statistically significant difference in the performance of the two instrument techniques in difficult cases showing better performance of the NiTi system and mean rotary preparation time (P < 0.001). Under the conditions of this study, novice dental students, using NiTi ProTaper rotary files, were able to prepare root canals faster with more preparation accuracy compared with canals of same teeth prepared with hand instruments.

Evaluación radiográfica y microscópica de la acción de quelantes en la remoción del barro dentinario / Radiographic and microscopic evaluation of the action of chelating agents in dental smear layer removal

Introducción: el tratamiento endodóntico realiza la limpieza y conformación del sistema de conductos radiculares, ya que virutas de dentina y materiales orgánicos, como los microorganismos, creadas por la acción de la instrumentación, forman el llamado barro dentinario. Objetivo: evaluar in vitro la remoción del barro dentinario y la disminución de la densidad de túbulos dentinarios, con soluciones irrigadoras quelantes. Métodos: se trata de un estudio experimental para el cual fueron seleccionados 30 dientes unirradiculares de humanos después del examen radiográfico inicial, y en el que se constató la presencia de canal único, ausencia de calcificación, reabsorción interna y tratamiento endodóntico concluido o en proceso. Luego se procedió a la instrumentación con tres diferentes soluciones irrigadoras: ácido etilenodiaminetetracético 17 por ciento, ácido cítrico 10 por ciento e hipoclorito de sodio 5,25 por ciento (grupo control). Posteriormente se evaluó radiográficamente cada diente instrumentado con el uso de una escala de densidad que fue confeccionada de aluminio con diferentes marcadores de densidades. Para el análisis por microscopio electrónico de barrido se utilizaron tres dientes de cada grupo, tratados con diferentes soluciones irrigadoras. Siete dientes de cada grupo se infiltraron con azul de metileno para la lectura de la infiltración marginal en el microscopio estereoscópico. Los dientes fueron evaluados en sus tres tercios: cervical, medio y apical. Resultados: se encontró que radiográficamente no hubo diferencia estadísticamente significativa entre los promedios de las densidades de los grupos de dientes en todos los tercios. Por microscopio electrónico de barrido se encontró una diferencia estadísticamente significativa entre los tres grupos de sustancias irrigadoras (p < 0,001), en el tercio cervical la remoción del barro dentinario fue mayor. Y por microscopio óptico se observó una mayor infiltración en el grupo de ácido etilenodiaminetetracético seguido del grupo ácido cítrico y por último el grupo control. Conclusión: el análisis de la densidad radiográfica y microscópica mostró que las sustancias quelantes fueron eficientes en la remoción del barro dentinario, excepto en el grupo control. Ninguna de las sustancias demostró alteraciones de densidad radiográfica de los túbulos dentinarios(AU)

Introduction: as part of endodontic treatment, root canals are cleaned and shaped, since shavings of dentin and organic materials, such as microorganisms, resulting from the action of instrumentation, create the so-called dental smear. Objective: carry out an in vitro evaluation of smear layer removal and dentinal tubule density reduction using chelating irrigation solutions. Methods: an experimental study was conducted for which 30 single-rooted human teeth were selected after initial radiographic examination to verify the presence of a single canal, absence of calcification, internal resorption and endodontic treatment either completed or underway. Next, instrumentation was performed with three different irrigation solutions: 17 percent ethylenediaminetetraacetic acid, 10 percent citric acid and 5.25 percent sodium hypochlorite (control group). Each instrumented tooth was then evaluated radiographically using a density scale made of aluminum with different density markers. Scanning electron microscope analysis was performed on three teeth from each group, which were treated with different irrigation solutions. Seven teeth from each group were infiltrated with methylene blue to determine marginal infiltration under the stereomicroscope. The teeth were evaluated on their three thirds: cervical, middle and apical. Results: radiographs did not reveal any statistically significant difference between the mean densities of the different groups of teeth in all thirds. Scanning electron microscopy showed a statistically significant difference between the three groups of irrigation substances (p < 0,001), with greater smear layer removal from the cervical third. Optical microscopy showed that infiltration was greatest in the ethylenediaminetetraacetic acid group, followed by the citric acid group, and lowest in the control group. Conclusion: analysis of radiographic and microscopic density revealed that except for the control group, chelating agents were efficient in removing dental smear. None of the substances showed any alteration in the radiographic density of dentinal tubules(AU)

Assessing accumulated hard-tissue debris using micro-computed tomography and free software for image processing and analysis.

INTRODUCTION: The accumulation of debris occurs after root canal preparation procedures specifically in fins, isthmus, irregularities, and ramifications. The aim of this study was to present a step-by-step description of a new method used to longitudinally identify, measure, and 3-dimensionally map the accumulation of hard-tissue debris inside the root canal after biomechanical preparation using free software for image processing and analysis. METHODS: Three mandibular molars presenting the mesial root with a large isthmus width and a type II Vertucci's canal configuration were selected and scanned. The specimens were assigned to 1 of 3 experimental approaches: (1) 5.25% sodium hypochlorite + 17% EDTA, (2) bidistilled water, and (3) no irrigation. After root canal preparation, high-resolution scans of the teeth were accomplished, and free software packages were used to register and quantify the amount of accumulated hard-tissue debris in either canal space or isthmus areas. RESULTS: Canal preparation without irrigation resulted in 34.6% of its volume filled with hard-tissue debris, whereas the use of bidistilled water or NaOCl followed by EDTA showed a reduction in the percentage volume of debris to 16% and 11.3%, respectively. The closer the distance to the isthmus area was the larger the amount of accumulated debris regardless of the irrigating protocol used. CONCLUSIONS: Through the present method, it was possible to calculate the volume of hard-tissue debris in the isthmuses and in the root canal space. Free-software packages used for image reconstruction, registering, and analysis have shown to be promising for end-user application.

Performance of RaCe instrumentation system in curved root canals: a comprehensive analysis by three study methods.

In this study, curved maxillary molar root canals were instrumented with RaCe rotary system to evaluate: 1. the occurrence of canal transportation using a radiographic platform; 2. the action of the instruments on the dentin walls, centering ability and canal enlargement by analysis of digital images; and the percentage of regular dentin surfaces and debris within the canal by histological analysis. Ten mesiobuccal roots of extracted human maxillary molars were embedded in acrylic resin and sectioned at the middle and apical thirds. Root canal shaping was performed using the RaCe rotary system at 250 rpm and 1 Ncm torque. Each instrument set was used five times according to a crown-down technique in the following sequence: 40/0.10, 35/0.08, 25/0.06, 25/0.04, 25/0.02 (working length - WL), 30/0.02 (WL) and 35/0.02 (WL). Each instrument was inserted until resistance was felt and then pulled back, followed by brushing movements towards all canal walls. Each specimen was assessed by three study methods: radiographic platform, digitized image assessment and histological analysis. The radiographic platform showed lack of apical transportation. No statistically significant difference (Wilcoxon test, p>0.05) was found between the middle and apical thirds regarding instrument action on dentin walls, centering ability, area of root canal enlargement, percentage of regular dentin surfaces and debris within the root canal. It may be concluded that RaCe system is a suitable method for the preparation of curved root canals, regarding the maintenance of root canal original path, action on dentin walls, canal enlargement and removal of debris from the root canal lumen.