The effect of sonic activated device used for different time on intracanal smear layer removal: An SEM analysis / 口腔医学

Objective @#To observe the clearance of smear layer on the root canal wall in different action time by scanning electron microscope (SEM), and to determine the optimal amount of time using sonically activated irrigation to wash root canal in clinic. @*Methods@# Fifty-six ex vivo human anterior teeth with single straight root canal were selected. After routine mechanical preparation, they were divided into two experimental groups according to different irrigating agents: saline group and EDTA group. Each group was assisted by VDW sonic activation EDDY. The saline group was divided into three subgroups according to the irrigating time: 5 s, 30 s and 50 s; EDTA group was divided into six subgroups according to the irrigating time: 5 s, 10 s, 20 s, 30 s, 40 s and 50 s. The control group did not undergo root canal irrigation. After irrigation, the root was cut longitudinally. The smear layer of crown, middle and apical of root canal wall was observed by SEM.@* Results@# After irrigating for 30 seconds, there was a significant difference between the normal saline group and the control group and the 5 second group (P<0.05), and there was no difference in the middle and apical part (P>0.05). After 50 seconds, there was a significant difference in the score of the smear layer between the apical area and the other groups (P<0.05). After irrigating for 5 seconds or 10 seconds in EDTA group, there was a significant difference between the scores of the crown and middle area of the root canal and the control group (P<0.05), and there was no significant difference in the apical area (P>0.05). There was a significant difference between the 20-40 second group and the first two groups (P<0.05). There was a significant difference between the 50 second group and the other groups (P<0.05). Comparing the cleaning effect on the smear layer after 50 seconds of irrigating between the two experimental groups, the whole root canal showed significant statistical difference (P<0.05). @*Conclusion @#The EDTA-assisted sonic activated device used for 50 seconds has the best cleaning effect.

Comparison of four methods that remove calcium hydroxide from root canals / 口腔疾病防治

Objective@# To compare the efficiency of four methods that remove calcium hydroxide in root canals and to guide clinical practice. @* Methods @# Sixty-five isolated mandibular single root canal premolars were collected. After crown cutting and root canal preparation, a tooth was randomly selected as the blank control group, and the remaining 64 teeth were equally divided into Groups A and B (n = 32). Group A was injected with water-soluble calcium hydroxide, and Group B was injected with oil-soluble calcium hydroxide. After 2 weeks of drug sealing, Groups A and B were randomly divided into 4 groups (n = 8), including the lateral opening syringe group, sonic vibration group, ultrasonic group, and Er: YAG laser group. Before and after calcium hydroxide removal, the samples were scanned by cone-beam CT, and the data were imported into Mimics for 3D reconstruction. The root canal was divided into the following segments: superior root segment, middle and apical, and the calcium hydroxide volume of each segment of the root canal was calculated. The volumes of calcium hydroxide before and after removal were V1 and V2, respectively, with a clearance rate = (V1-V2)/V1×100%. Three-factor ANOVA was used for statistical analysis. After Groups A and B were reconstructed, the apical region with residual calcium hydroxide was selected, and the blank control was observed by scanning electron microscopy (SEM). @*Results @# Two types of calcium hydroxide could not be completely removed by the four flushing methods. The clearance rate of water-soluble calcium hydroxide was higher than that of oil-soluble calcium hydroxide (P<0.001). Among the three segments of the root canal, the clearance rate of the apical segment was lower (P<0.05). The Er: YAG laser treatment group showed the highest removal efficiency of two kinds of calcium hydroxide, which was higher than that of the other groups, especially in apical of the root. Compared with the sonic wave washing group and the syringe washing group, the ultrasonic wave washing group exhibited significant advantages (P<0.05). The clearance rate of the sonic wave washing group was higher in the oily calcium hydroxide root middle group than in the syringe washing group (P<0.05). SEM showed that the two kinds of calcium hydroxide could not be completely removed, but the residual rate of oil-soluble calcium hydroxide was large.@*Conclusion @# Both types of calcium hydroxide could not be completely removed, and compared to water-soluble calcium hydroxide, oil-soluble calcium hydroxide was more difficult to remove. Among the four cleaning methods, Er:YAG laser swing washing showed the higher cleaning efficiency.

The penetration effect of ultrasound and Er:YAG laser irrigation activation techniques on dentine of infected human root canals / 口腔疾病防治

Objective@#This ex vivo study evaluated the effect of ultrasound and Er:YAG laser irrigation activation techniques on the penetration of sodium hypochlorite solution into infected human root canal dentin, providing a reference for clinical infection control of infected root canals.@*Methods @#Thirty-six cases of infected root canals were collected and randomly divided into three groups according to the irrigation technique: 12 cases in the conventional syringe irrigation (CSI) group, 12 cases in the passive ultrasonic irrigation (PUI) group, 12 cases in the Er:YAG laser and photon-induced photoacoustic streaming (PIPS) group and 36 cases of clean root canals (12 cases in the CSI group, 12 cases in the PUI group, 12 cases in the PIPS group). All of the selected root canals were straight root canals of posterior teeth. After standardizing the root length, all canals were subjected to instrumentation and dynamic irrigation. 2% methylene blue solution was used to visualize the penetration of the irrigant. EXAKT cutting and grinding equipment was used to take transverse sections of 100-150 μm at the coronal, middle and apical thirds of the root canals. The data (maximum penetration depth, average penetration depth, and penetration percentage) were observed under a light microscope to evaluate the effect of dye penetration. @*Results @# With the three irrigation techniques, the maximum penetration depth, average penetration depth and penetration percentage of the infected root canals were significantly lower than those of clean root canals in the full length of the root canal (P<0.05). The penetration percentage, average penetration depth and maximum penetration depth of the PIPS group were significantly higher than those of the CSI group in the coronal, middle and apical thirds of the infected root canal, respectively (P<0.05). There was no significant difference in the maximum penetration depth, average penetration depth or penetration percentage between the PUI and CSI groups (P>0.05). There was also no significant difference in the maximum penetration depth, average penetration depth or penetration percentage between the PIPS and PUI groups (P>0.05). @*Conclusion @# The dentine permeability of infected root canals was weaker than that of clean root canals. Er:YAG laser-assisted irrigation activation technology could significantly improve the penetration of sodium hypochlorite solution into infected dentin, but passive ultrasonic irrigation did not significantly improve the penetration.

Application of a one-time filling root canal in root canal therapy in plateau areas / 中国基层医药

Objective:To investigate the application effects of a one-time filling root canal in root canal therapy in plateau areas and evaluate its feasibility in oral clinic in plateau areas.Methods:Sixty-eight patients who received root canal therapy for anterior teeth and premolars (75 teeth) from August to December 2018 in Shannan People's Hospital were included in this study. They were divided into control group ( n = 33; 36 teeth) and observation group ( n = 35; 39 teeth) according to odd and even numbers of admission date. Patients in the control group received conventional root canal therapy and those in the observation group underwent one-time root canal filling therapy. Efficacy was compared between the two groups. Results:After 1 week, 2 weeks and 1 month of treatment, the success rate in the control group was 88.9%, 94.4%, 100.0%, respectively, and it was 87.2%, 94.9% and 100.0%, respectively in the observation group. There was no significant difference in success rate between the two groups at three time points studied (all P > 0.05). Conclusion:One-time filling root canal therapy can achieve ideal therapeutic effects under strict control of surgical indications. This method is worthy of clinical promotion especially in plateau areas.

The effect of Er: yttrium aluminum garnet laser irrigation on the root canal smear layer and root canal microhardness / 中华老年医学杂志

Objective:To examine the effects of different endodontic irrigation methods on root canal morphology.Methods:We collected 20 extracted single-root premolars from elderly patients(≥60 years)with periodontitis and randomly divided them into 5 groups.Group A: syringe irrigation; Group B: P5 ultrasonic irrigation, Group C: 0.20 W Er: yttrium aluminum garnet(YAG)laser irrigation; Group D: 0.30 W Er: YAG laser irrigation; and Group E; 0.35 W Er: YAG laser irrigation.Changes in the smear layer in the root canal and the hardness of the root canal were assessed.Results:After treatment with different root canal cleaning methods, the scores of smear layer removal for Groups A, B, C, D and E were(4.67±0.27), (3.08±0.57), (2.83±0.43), (1.17±0.19)and(2.87±0.50), respectively.There were statistically significant differences between them( F=35.946, P<0.01). Among them, Group B, C, D and E had better smear layer removal than Group A, and the differences were statistically significant(all P<0.01). Group D had better removal of the smear layer than Groups B, C and E, and the differences were statistically significant( P<0.01); Values for dentin microhardness of Groups A, B, C, D and E were(58.98±5.54), (55.19±5.71), (56.04±3.96), (66.65±3.23)and(45.68±7.58), respectively, with statistically significant differences( F=5.83, P<0.05), and for laser-based irrigation, the value for dentin microhardness of Group D was higher than those of groups C and B(all P<0.05). Conclusions:Laser-based root canal irrigation is better than traditional irrigation methods, with 0.30 W Er: YAG laser achieving maximal removal of the smear layer and at the same time having the least impact on root canal hardness.

The clinical application of ultrasonic root canal intermittent irrigation in endodontic vascular reconstruction / 中国医师杂志

Objective:To investigate the clinical effect of ultrasonic root canal intermittent irrigation in endodontic vascular reconstruction.Methods:32 young permanent teeth with pulp and periapical lesions were randomly divided into two groups ( n=32): experimental group was treated with ultrasonic root canal intermittent irrigation and the control group was rinsed with sodium hypochlorite root canal. The changes of periapical lesions and root development were evaluated by preoperative and postoperative clinical symptom observation and radiograph examination, and the clinical effect of endodontic vascular reconstruction was discussed. The time of inflammation control was discussed by analyzing the starting point from the first diagnosis to the date of mineral trioxide aggregate (MTA) coverage. Results:The clinical symptoms of the 16 affected teeth in the experimental group and the control group disappeared, the periapical lesions were eliminated, and the root continued to develop. In the experimental group, root formation was observed in 13 of the affected teeth, with a success rate of 81.25% and a reduction rate of 18.75%. In the control group, root formation was observed in 10 of the affected teeth, with a success rate of 62.5% and a reduction rate of 37.5%. There was no difference in the effective rate between the experimental group and the control group ( P>0.05). The control time of inflammation was (28.44±5.98)days in the experimental group and (34.13±7.17)days in the control group, with statistically significant differences ( P<0.05). Conclusions:Ultrasonic root canal intermittent swabbing applied to pulp revascularization can achieve good clinical effect and shorten the time of inflammation control.

Location, incidence and clinical implications of the root canal isthmus / 口腔疾病防治

@#Root canal isthmus(RCI) is defined as a narrow, ribbon-shaped communication between two root canals that contains pulp or tissue derived from pulp. Any root that contains two or more root canals has the potential to contain an isthmus. The incidence of RCI from different tooth positions varies, with the highest RCI incidences usually found in the mesial root of the mandibular first molar and the mesiobuccal root of the maxillary first molar. The presence of RCI increases the difficulty of root canal therapy and introduces uncertainty regarding the prognosis for dental treatment. It is recommended to use CBCT and dental microscopy to identify teeth with suspected RCI in clinical practice. At the same time, for treatment of teeth with RCI, appropriate instruments should be selected, and enhanced root canal irrigation assisted by ultrasound should be considered to improve the success rate of root canal treatment and endodontic root-end surgery. The current technology still has some limitations regarding the cleaning and filling of RCI and additional research and development. Improvement of the corresponding technology and equipment is a current research hotspot and a future research direction.

Computational fluid dynamics analysis of the flow of ultrasonic irrigations in root canal / 口腔疾病防治

Objective@#To study the computational fluid dynamics (CFD) characteristics of ultrasonic root canal irrigation when the file was placed at a certain depth in the root canal, to provide a reference for clinical application.@*Methods @#First, scanning laser vibrometry (SLV) was utilized to analyze the characteristics of vibrational ultrasonic files under specific power. Then ICEM CFD 18.0 software was used to establish the root canal ultrasonic irrigation model. The insertion position of the ultrasonic working tip was set 1 mm away from the physiological apical foramen, and cloud images of the results were obtained by FLUENT 18.0 software. Volume fraction, flow velocity and pressure in the root canal were evaluated after setting the computing conditions.@*Results@#The vibration of the ultrasonic working tip was mainly transverse vibration with slight longitudinal vibration. The amplitude of transverse vibration of each part of the working tip was different. Maximum values were observed at the apical end area of the file, and the closer to the base of the file, the smaller the amplitude. The area where the cavitation volume fraction of the rinsing fluid was greater than 0 was concentrated around the working point. The flow rate of the irrigating fluid was up to 2 m/s, within the area 0.2 mm in front of the working tip, the velocity of the irrigating fluid was greater than 0.1 m/s, while within the area 0.8 mm from the root tip, the velocity of the irrigating fluid was small or even zero. The apical pressure value was non-positive when the tip of the file was 1 mm away from the apical foramen in this model.@*Conclusion@# Based on the experimental results, it appears that when the ultrasonic working tip was placed 1 mm short of the working length, the ultrasonic irrigating flow did not overflow the root apical foramen and the irrigation process was relatively safe; the irrigation fluid had a strong irrigation effect within approximately 0.2 mm in front of the working tip.

Tendências atuais no tratamento endodôntico por cirurgiões dentistas no Brasil / Current trends in endodontic treatment by dental surgeons in Brazil

Objetivo: conhecer as principais práticas adotadas atualmente por cirurgiões dentistas, clínicos gerais e endodontistas na realização do tratamento endodôntico. Material e Métodos: um questionário contendo 21 perguntas de múltipla escolha foi enviado para os profissionais, nas cinco regiões do país. As perguntas abordaram o tempo de experiência, tipos de técnicas, materiais e recursos auxiliares. Resultados: a maior parte dos respondentes são do Sudeste e Sul, endodontistas há menos de 10 anos. Realizam até 20 tratamentos/mês, utilizam localizador apical, instrumentação manual com limas de aço inoxidável associada a brocas gates glidden/largo, lupa e isolamento absoluto. O hipoclorito de sódio (2,5 a 5%) e o EDTA são os irrigantes mais utilizados juntamente com o ultrassom. O tratamento é feito em sessão única, porém o diagnóstico pulpar pode alterar o número de sessões. Quando é necessário o uso de medicação intracanal, o hidróxido de cálcio associado a outras formulações é a primeira escolha. Para obturação do sistema de canais radiculares é utilizada a técnica de condensação lateral e o cimento à base de óxido de zinco e eugenol. O selamento coronário entre sessões é feito com coltosol e com cimento de ionômero de vidro ao término do tratamento, quando os pacientes são encaminhados a outro profissional para restauração final. Atualizam-se através de artigos científicos e mostram abertura para testar novos produtos. Conclusão: a maioria dos participantes aderem a práticas atuais com uso de novas tecnologias durante o tratamento e se atualizam através da leitura de artigos científicos

Objective: to be aware of the main practices currently adopted by general dentists and endodontists when performing endodontic treatments. Material and methods: a questionnaire containing 21 multiple-choice questions was sent to professionals in the five regions of Brazil. These questions covered experience time, techniques, materials and auxiliary resources. Results: most participants are from the Southeast and South regions of Brazil and have been specialized in endodontic for less than 10 years. They perform up to 20 treatments per month, use apex locator, manual instrumentation with stainless steel files associated with gates-glidden or largo burs, magnifying loupes and absolute isolation. Sodium hypochlorite (2.5 to 5.0%) and EDTA are the most used substances for irrigation associated with ultrasound. The treatment is done in a single visit, but pulp diagnosis might alter the number of visits. When intracanal medication is required, calcium hydroxide associated with other formulations is the first choice. For root canal filling, lateral condensation technique, zinc oxide and eugenol based sealers are used. Coronal sealing between sessions is done with Coltosol® and glass ionomer cement at the end of treatment, when patients are referred to another professional for final restoration. These professionals update their knowledge with scientific articles and show availability to test new products. Conclusion: most participants have been adhering to current practices (new technologies) during treatment and has kept updated by reading scientific articles

Accidente con hipoclorito de sodio durante la terapia endodóntica / Accident with sodium hypochlorite during endodontic therapy

Introducción: el accidente con hipoclorito de sodio es una de las complicaciones que pueden presentarse durante la terapia endodóntica convencional. Constituye el sobrepaso del irrigante a los tejidos periapicales ya sea durante la irrigación de los conductos radiculares o por medio de la inyección accidental en los tejidos blandos. Produce al paciente una sintomatología dolorosa inmediata, con una respuesta inmunológica exacerbada y necrosis hística. Objetivo: determinar las posibles causas del accidente con hipoclorito de sodio y exponer el protocolo de manejo clínico y farmacológico establecido para esta eventualidad. Caso clínico: se informa el caso de un sobrepaso accidental de hipoclorito de sodio hacia el periápice en la raíz distovestibular del diente 17 en un paciente de 67 años de edad, con hipertensión arterial controlada, diagnóstico de pulpa sana y requerimiento de realización de endodoncia preprotésica. Se exponen la toma de medidas clínicas y farmacológicas posterior al accidente con hipoclorito de sodio, así como el suministro de corticoterapia inmediata, analgesia, manejo del dolor por bloqueo anestésico del área comprometida y para disolución del hipoclorito de sodio, para completar el esquema de manejo medicación antibiótica profiláctica. Conclusiones: los factores predisponentes para la generación de un accidente con hipoclorito son: enfermedades que causen resorción periapical, selección inadecuada del tipo de jeringa y aguja con la que se realiza la irrigación y la no determinación adecuada de la longitud radicular. El manejo de estos accidentes con corticoides y analgesia reduce la agresividad de la sintomatología presentada por el paciente, así como la profilaxis antibiótica, disminuye el riesgo de daño hístico(AU)

Introduction: sodium hypochlorite accidents are one of the complications that may arise during conventional endodontic therapy. In hypochlorite accidents, the irrigant flows into the periapical tissue either during irrigation of root canals or by accidental injection into soft tissue. This situation causes immediate pain symptoms in the patient, with an exacerbated immune response and tissue necrosis. Objective: determine the possible causes of sodium hypochlorite accidents and present the clinical and pharmacological management protocol established for these events. Clinical case: a case is reported of accidental flowing of sodium hypochlorite to the apex of the distovestibular root of tooth 17 in a 67-year-old male patient with controlled hypertension and a diagnosis of healthy pulp requiring preprosthetic endodontic therapy. A description is provided of the clinical and pharmacological actions taken after the sodium hypochlorite accident, as well as the immediate application of corticotherapy, analgesia, pain management by anesthetic block of the compromised area and for dissolution of the sodium hypochlorite, to complete the management scheme with prophylactic antibiotic medication. Conclusions: the following are predisposing factors for the occurrence of a hypochlorite accident: conditions that cause periapical resorption, inadequate choice of the type of syringe and needle to perform the irrigation, and incorrect determination of the root length. Management of these accidents with corticosteroids and analgesia reduces the aggressiveness of symptoms, whereas antibiotic prophylaxis lessens the risk of tissue damage(AU)

Efficacy of relacin combined with sodium hypochlorite against Enterococcus faecalis biofilms

Abstract Objective Relacin is a synthetic molecule that targets RelA, an essential protein in a conserved bacterial stress response system. It was shown to inhibit bacterial growth. The aims of this study were to evaluate the antimicrobial effect of relacin combined with sodium hypochlorite (NaOCl) on Enterococcus faecalis biofilms and to evaluate the cytotoxicity of relacin. Material and Methods 48-h E. faecalis OG1RF biofilms were treated by various concentrations of relacin in order to determine its inhibitory concentration. Then, the 48-h biofilms were treated either with 1-min NaOCl (0.01%, 0.05%) alone, or in combination of relacin. As a means of comparison, the biofilms of ΔrelA were also treated by 1-min NaOCl (0.01%, 0.05%, 0.25%). The treatment efficacy was determined by agar plate count assays. The cytotoxicity of relacin was examined on human gingival epithelial cells Ca9-22 and murine fibroblasts NIH-3T3 by a methyl thiazolyltetrazolium (MTT) assay and a lactate dehydrogenase assay. Statistical analysis was performed by one-way or two-way analysis of variance (ANOVA) with Bonferroni's post-hoc test and an independent Student's t-test. A significance level of p<0.05 was used. Results Relacin inhibited the growth of OG1RF biofilms partially at 8 mM and fully at 14 mM. The relacin (14 mM) and NaOCl combined treatment resulted in significantly higher treatment efficacy than NaOCl treatment alone. At 0.05% NaOCl, the combined treatment resulted in 5.65 (±0.19) log reduction in biofilm viability. The ΔrelA biofilms were more susceptible to NaOCl treatment than the wild type biofilms at 0.25% NaOCl. Relacin at 14 mM was not toxic to host epithelial cells and fibroblasts. Conclusions The combination of relacin with a low concentration of NaOCl was effective and not cytotoxic.

Effect of an Alcohol-Based Caries Detector on the Surface Tension of Sodium Hypochlorite Preparations

The purpose of this study was to evaluate the effect of an alcohol-based caries detector (Kurakay) on the surface tension of a conventional sodium hypochlorite (NaOCl) preparation, and a product containing a surface-active agent (Chlor-XTRA). The surface tensions of the following solutions were tested: NaOCl, a mixture of NaOCl and Kurakay 9:1 w/w, Chlor-XTRA, a mixture of Chlor-XTRA and Kurakay 9:1 w/w. Ten measurements per test solution were made at 20 C, using an optical method called the "Pendant drop method", with a commercially available apparatus. The addition of Kurakay reduced the surface tension for NaOCl (p<0.05) whilst no significant difference was detected for Chlor-XTRA (p>0.05). Statistically significant differences between the NaOCl and Chlor-XTRA groups were found (p<0.05). The addition of an alcohol-based caries detector resulted in a reduction of the original surface tension values for NaOCl only. Taking into account the fact that mixtures of NaOCl and Kurakay have been used to assess the penetration of root canal irrigants in vitro, the related changes in surface tension are a possible source of bias.

O objetivo deste estudo foi avaliar o efeito de um detector de cárie com álcool (Kurakay) sobre a tensão superficial de um preparado convencional de hipoclorito de sódio (NaOCl) e um produto contendo um agente surfactante (Chlor-XTRA). Foram testadas as tensões superficiais das seguintes soluções: NaOCl, uma mistura de NaOCl e Kurakay na proporção de 9:1 em peso, Chlor-XTRA e um mistura de Chlor-XTRA e Kurakay na proporção de 9:1 em peso. Dez medidas foram feitas com cada solução, a 20 °C, utilizando um método óptico chamado "Método da gota pendente" (Pendant drop method) usando aparelhos disponíveis. Adição do Kurakay reduziu a tensão superficial do NaOCl (p<0,05), mas não houve diferença significante para Chlor-XTRA (p>0,05). Foram encontradas diferenças estatisticamente significantes entre os grupos NaOCl e Chlor-XTRA (p<0,05). Adição de um detector de cárie com álcool resultou na diminuição do valor original da tensão superficial apenas para NaOCl. Considerando que as misturas de NaOCl e Kurakay tem sido usadas para estudar a penetração in vitro dos irrigantes radiculares, as diferenças acima são uma possível fonte de desvio nos resultados.

Root Canal Penetration of a Sodium Hypochlorite Mixture Using Sonic or Ultrasonic Activation

The purpose of this ex vivo study was to determine, in "open" and "closed" systems, whether the design has an influence on the penetration length of sodium hypochlorite mixed with a radiopaque contrast medium, measured in millimeters, when delivered using positive pressure (PP) and using sonic (SI) or passive ultrasonic (PUI) activation. Sixty single-rooted teeth were divided into two groups: open and closed systems (n=30). Root canal shaping was performed to a working length of 17 mm. The samples were divided into three sub-groups (n=10) according to irrigant delivery and activation: PP, and SI or PUI activation. By using radiographs, penetration length was measured, and vapor lock was assessed. For the closed group, the penetration distance means were: PP 15.715 (±0.898) mm, SI 16.299 (±0.738) mm and PUI 16.813 (±0.465) mm, with vapor lock occurring in 53.3% of the specimens. In the open group, penetration to 17 mm occurred in 97.6% of the samples, and no vapor lock occurred. Irrigant penetration and distribution evaluation using open and closed systems provide significantly different results. For closed systems, PUI is the most effective in delivering the irrigant to working length, followed by SI.

O objetivo deste estudo in vivo foi determinar, para os sistemas "abertos" e "fechados", se o design tem influência na penetração, em milímetros, do hipoclorito de sódio misturado com um meio radiopaco quando empregado na ativação com pressão positiva (PP) e ativação sônica (SI) ou ultrassônica passiva (PUI). Sessenta dentes unirradiculares foram divididos em dois grupos: sistema aberto e sistema fechado (n=30). Os canais radiculares foram trabalhados até um comprimento de trabalho de 17 mm. Os grupos foram subdivididos em três subgrupos (n=10) de acordo com a solução irrigadora e a ativação: PP, e ativação SI ou PUI. Usando radiografias, a distância de penetração foi medida e avaliado o vapor contido. Para o grupo fechado, as distâncias médias de penetração foram PP 15,715 (±0,898) mm, SI 16,299 (±0,738) mm e PUI 16,813 (±0,465) mm e houve vapor contido em 53,3% das amostras. No grupo aberto, houve penetração de 17 mm em 97.6% das amostras, sem contenção de vapor. A penetração do irrigante e avaliação da distribuição usando sistemas aberto e fechado produziram resultados significativamente diferentes. Para os sistemas fechados, PUI é mais eficaz para levar o irrigante até preencher o comprimento de trabalho, seguido por SI.

Effect of the morphology of S-shaped root canals with reciprocating single file system on root canal irrigation / 中南大学学报(医学版)

Objective: To evaluate effect of the morphology of simulated S-shaped root canals with Reciproc or Mtwo instruments on root canal irrigation. Methods: A total of 40 simulated S-shaped resin blocks were randomly divided into 2 groups (n=20), which was prepared by Reciproc or Mtwo. Blue ink was injected with constant speed and volume into the canals using 30G lateral opening syringe. hTe distance from needle tip to apex and vapor lock length were measured. A type of 25# 0.04 gutta-percha point was used to stir and remove the vapor lock. hTe time for removal of the vapor lock was recorded. Another syringe was used to inject saline into the canals and to measure the length of stagnant water. Results: hTe distance from needle tip to apex in the Reciproc group was signiifcantly longer than that in the Mtwo group [(4.276 ± 0.221) mm vs (3.459 ± 0.205) mm,P<0.05]. The vapor lock length in the Reciproc group was signiifcantly longer than that in the Mtwo group [(4.472 ± 0.230) mm vs (3.668±0.217) mm,P<0.05]. hTe time to remove vapor lock was signiifcantly shorter in the Reciproc group than that in the Mtwo group [(10.13 ± 1.79) s vs (15.29 ± 2.15) s,P<0.05]. The length of stagnant water was also shorter in the Reciproc group than that in the Mtwo group[(1.351 ± 0.142) mm vs (2.245 ± 0.206) mm,P<0.05]. Conclusion: hTe morphology of S-shaped root canal affects the root canal irrigation. hTe effect of root canal irrigated by Reciproc is better than that by Mtwo.

Effectiveness of temperature and activating instrument on smear layer removal / 实用口腔医学杂志

Objective:To compare the efficacy of six different irrigation techniques on smear layer removal.Methods:60 single-rooted teeth were prepared.The root canals were irrigated with NaOCl at 20 ℃ or 60 ℃,and activated with side-vented needle,pas-sive ultrasonic irrigation (PUI)and EndoActivator (EA)irrigation techniques respectively.Then teeth were randomly divided into 6 groups(n =1 0):20 ℃-PUI group,20 ℃-EA group,20 ℃control group,60 ℃-PUI group,60 ℃-EA group and 60 ℃ control group.Smear layer was observed under thermal field emission scanning electron microscope(FE-SEM)and scored according to the cri-teria specified by Hulsmann M.Results:The smear layer removal effect in 60 ℃ groups was better than that in 20 ℃ groups (P <0.05),and better in 20 ℃-EA and 20 ℃-PUI groups than in 20 ℃ control group(P <0.05).Conclusion:The temperature of NaOCl is the main factor influencing the smear layer removal,NaOCl at 60 ℃ is more effective than that at 20 ℃.

Review of root canal irrigant delivery techniques and devices / 대한치과보존학회지

INTRODUCTION: Eliminating the residual debris and bacteria in the root canal system is one of the main purposes of the endodontic treatment. However, the complexity on the anatomy of the root canal system makes it difficult to eliminate the bacterial biofilm existing along the root canal surface and necrotic pulp tissue by mechanical instrumentation and chemical irrigation. Recently, more effective irrigant delivery systems for root canal irrigation have been developed. The purpose of this review was to present an overview of root canal irrigant delivery techniques and devices available in endodontics. REVIEW: The contents of this paper include as follows; - syringe-needle irrigation, manual dynamic irrigation, brushes - sonic and ultrasonic irrigation, passive ultrasonic irrigation, rotary brush, RinsEndo, EndoVac, Laser CONCLUSION: Though technological advances during the last decade have brought to fruition new agitation devices that rely on various mechanisms, there are few evidence based study to correlate the clinical efficacy of these devices with improved outcomes except syringe irrigation with needle and ultrasonic irrigation. The clinicians should try their best efforts to deliver antimicrobial and tissue solvent solutions in predictable volumes safely to working length.

Evaluation of the antimicrobial effect of super-oxidized water (Sterilox®) and sodium hypochlorite against Enterococcus faecalis in a bovine root canal model

ABSTRACT Ideally root canal irrigants should have, amongst other properties, antimicrobial action associated with a lack of toxicity against periapical tissues. Sodium hypochlorite (NaOCl) is a widely used root canal irrigant, however it has been shown to have a cytotoxic effect on vital tissue and therefore it is prudent to investigate alternative irrigants. Sterilox's Aquatine Alpha Electrolyte® belongs to the group of the super-oxidized waters; it consists of a mixture of oxidizing substances, and has been suggested to be used as root canal irrigant. Super-oxidized waters have been shown to provide efficient cleaning of root canal walls, and have been proposed to be used for the disinfection of medical equipment. OBJECTIVE: To compare the antimicrobial action against Enterococcus faecalis of NaOCl, Optident Sterilox Electrolyte Solution® and Sterilox's Aquatine Alpha Electrolyte® when used as irrigating solutions in a bovine root canal model. METHODOLOGY: Root sections were prepared and inoculated with E. faecalis JH2-2. After 10 days of incubation the root canals were irrigated using one of three solutions (NaOCl, Optident Sterilox Electrolyte Solution®and Sterilox's Aquatine Alpha Electrolyte®) and subsequently sampled by grinding dentin using drills. The debris was placed in BHI broth and dilutions were plated onto fresh agar plates to quantify growth. RESULTS: Sodium hypochlorite was the only irrigant to eliminate all bacteria. When the dilutions were made, although NaOCl was still statistically superior, Sterilox's Aquatine Alpha Electrolyte® solution was superior to Optident Sterilox Electrolyte Solution®. CONCLUSIONS: Under the conditions of this study Sterilox's Aquatine Alpha Electrolyte® appeared to have significantly more antimicrobial action compared to the Optident Sterilox Electrolyte Solution® alone, however NaOCl was the only solution able to consistently eradicate E. faecalis in the model.

Análise histológica dos tecidos periapicais de dentes de cães como recurso para avaliar a influência dos auxiliares químicos da instrumentação no selamento dos canais radiculares obturados com RealSeal® e expostos ao meio bucal / Histological analysis of periapical tissue of dogs´ teeth as a means to evaluate the influence of irrigating solutions in the sealing of root canals filled with RealSeal® and exposed to oral environment

Este estudo, in vivo, visou a avaliar a influência do auxiliar químico no selamento dos canais radiculares obturados com o sistema RealSeal® e preparados para a colocação de pino protético, pela análise da resposta dos tecidos periapicais de dentes de cães. Foram testados os produtos químicos hipoclorito de sódio a 1% e a clorexidina gel a 2%. A pesquisa foi desenvolvida em 6 cães, 10 dentes em cada um deles, num total de 60 dentes e 120 canais divididos em sete grupos, sendo três grupos teste, três grupos controle negativo e um grupo controle positivo. Todos os dentes permaneceram selados por 24 horas após terem sido tratados. Decorrido este prazo, os selamentos provisórios dos dentes pertencentes aos grupos teste e controle positivo foram removidos, permanecendo sem selamento por 90 dias. Os dentes dos grupos controle negativo foram mantidos com selamento durante todo o período experimental, quando os animais foram mortos e suas mandíbulas removidas. O processamento histológico foi realizado com hematoxilina e eosina. A análise histológica, com auxílio de um microscópio óptico, baseou-se na avaliação da situação histológica dos tecidos periapicais. A análise estatística foi realizada a partir do teste não paramétrico de Kruskal-Wallis com localização de diferenças pelos procedimentos de post-hoc, de Mann-Whitney e Willcoxon. O nível de significância considerado adequado foi de 5%. Os grupos experimentais...

The aim of this study was to assess the influence of the cleaning protocol on sealing of root canal obturation with RealSeal following post space preparation, by means of periapical tissue response analysis. 1% sodium hypochlorite and 2% chlorhexidine were the tested products. For this purpose, six dogs were used, 10 teeth in each dog, comprising a total of 60 teeth and 120 root canals, were randomly divided into seven groups, being three test groups, three negative controls and a positive control. Following obturation, all teeth were kept totally sealed during 24 hours to allow sealer setting. Then the positive control and the three test groups had their seal removed, and obturation material exposed to the oral environment for 90 days. Negative controls were kept sealed during the whole experimental period. The animals were killed and their mandibles removed. Histological procedures were adopted as to HE staining. Optical histological analysis at magnifications varying from 25x to 400x considered the periapical tissue status at various sites...

Cleaning ability of chlorhexidine gel and sodium hypochlorite associated or not with EDTA as root canal irrigants: a scanning electron microscopy study

The aim of this study was to evaluate the cleaning efficacy of 2 percent chlorhexidine gluconate gel (CHX) compared to 2.5 percent sodium hypochlorite solution (NaOCl) associated or not with 17 percent EDTA used as irrigants during the biomechanical preparation. Fifty freshly extracted single-rooted human teeth with complete apex formation were randomly divided into five groups: G1 - sterile saline, G2 - 2.5 percent NaOCl, G3 - 2 percent CHX, G4 - 2.5 percent NaOCl + EDTA and G5 - 2 percent CHX + EDTA. The specimens of G1 were subdivided into two control groups. The teeth were decoronated and the coronal and middle root thirds were prepared with Gates-Glidden burs, and the apical third was reserved to manual instrumentation. All procedures were performed by a single operator. In all groups, 2 mL of irrigant was delivered between each file change. The teeth were sectioned and prepared for analyses under scanning electron microscopy (SEM). SEM micrographs were graded according to a score scale by two examiners. Data were analyzed statistically by Kruskal-Wallis and Dunn tests at 1 percent significance level. The best results were obtained in the groups in which the irrigant was used followed by the chelating agent. No statistically significant difference was observed among G4, G5 and the positive control group (p<0.01). The groups G2 and G3 were significantly different from the others, presenting the worst cleaning capacity. In conclusion, the use of the chelating agent is necessary to obtain clean canal walls, with open tubules and no heavy debris. The use of 2 percent chlorhexidine gluconate gel alone is not able to remove the smear layer.