Effects on the incidence of dentinal microcracks in curved root canal preparation with ProTaper Universal and ProTaper Gold / 口腔疾病防治

Objective@#This study aims to compare the incidence of dentinal microcracks produced by ProTaper Universal (PTU) and ProTaper Gold (PTG) file systems during root canal procedures in different curved canals using a dyeing technique.@*Methods@#Sixty extracted human molars were divided into 3 groups of 20 samples each in terms of root curvature (mild bending group, 10 °-19 °; moderate bending group, 20 °-29 °; severe bending group, 30 °-39 °). Ten samples of each group were then randomly allocated to the PTU and PTG file systems. After preparation, all roots were stained using a dyeing method and sectioned at the most curved plane and 2 mm below and above the most curved plane with a low-speed saw under cold water. A stereomicroscope was used to inspect dentinal microcracks at 60 × magnification, and differences between these three instrument groups were analyzed using the chi-square test.@* Results @# The PTG file system induced significantly fewer dentinal microcracks for total, incomplete and complete cracks (P < 0.05), and the effect was more obvious with increasing canal curvature.@*Conclusion @# With the limitations of this in vitro study, it can be concluded that ProTaper Gold can result in fewer dentinal microcracks than ProTaper Universal.

Evaluation of Push Out Bond Strength of Two Calcium Silicate Based Cements with Bone Cement in Retrograde Cavities Prepared by Ultrasonic Retro Tips

Introduction: Surgical endodontic treatment comprises ofthorough debridement of pathological periradicular tissue,root end resection followed by a Class I retrograde cavitypreparation and insertion of root end filling material into theprepared cavity. The aim of this study was to evaluate the pushout bond strength of Biodentine, Mineral Trioxide Aggregate(MTA) and Bone Cement used in the retro cavities, preparedwith ultrasonic retro tips.Material and methods: 60 human extracted single rootedteeth were selected and sectioned with a diamond disc (Horico,Germany) to standardize the root length of 15mm. The rootswere instrumented with rotary ProTaper Universal (DentsplyMaillefer) system till size F2. The root canals were obturatedusing gutta percha (Dentsply, Maillefer) and AH Plus sealer(Dentsply, Germany). 3mm of root end resection wasperformed with high speed hand piece under water coolant.3mm deep retro cavities were prepared with ultrasonic stainlesssteel retro tip (Woodpecker). All the specimens were dividedinto 3 groups (n=20) Group I: MTA (ProRoot, Tulsa Dental,USA), Group II Biodentine (Septodont, France), Group IIIBone Cement (Depuy, Johnsons and Johnsons). Each materialwas mixed according to the manufacturers instructions andfilled into the retro cavities. The specimens were sectionedperpendicularly to obtain 1mm thick slices from the apicalportion and subjected to push out bond strength testing underUniversal Testing Machine (Instron).Results: Biodentine showed more push out bond strength thanMTA and Bone Cement. There was no significant differencebetween MTA and Bone Cement groups.Conclusion: Bone Cement can be considered as one of thepotential retro filling material.

Comparison of the formation ability of two types of machine-made nickel-titanium instruments in simulated curved root canals / 口腔疾病防治

Objective@#To compare ProTaper Universal (PU) and M3-L instruments in preparing curved root canals and to provide a reference for clinical applications.@*Methods@#Twenty resin-simulated curved single root canals were randomly divided into two groups. Root canal preparation was performed with a PU nickel-titanium file or an M3-L nickel-titanium file. Root canal preparation time, root canal length before and after preparation and root canal deviation were recorded.@*Results@#In the M3-L group, the displacement measured at the 4th to 7th sites was less than that in the PU group (P < 0.05), but there was no significant difference between the other two groups (P > 0.05); The length of the root canal before and after root canal preparation in the M3-L group was （14.90 ± 1.92）mm and （14.57 ± 1.13）mm, respectively, and the difference between the two groups was not statistically significant (t=3.18, P=0.058). The root canal length before and after root canal preparation in the PU group was（14.53 ± 1.53）mm and （14.28 ± 1.39）mm, respectively. The difference between the two groups was not statistically significant（t=2.12,P=0.124）; The average preparation time of the M3-L group [（110.15 ± 10.43）s] was less than that in the PU group [（330.48 ± 12.62）s] (P < 0.05).@*Conclusion @#The M3-L nickel-titanium file has better central positioning ability and is less time-consuming than the PU nickel-titanium file in root canal bending preparation.

Comparison Of Instrumentation Time And Cleaning Efficacy Of Manual K–File, Rotary Protaper Universal And Rotary Protaper Next In Primary Anterior Teeth: An In–Vitro Study

Introduction: Pulpectomy of primary teeth with severe pulpal involvement is one of the most important concerns in Pediatric Dentistry.Root canal instrumentation is performed with files, reamers, sonic instruments and recently with rotary instruments. Although manual instrumentation is widely used in primary teeth, but they have limitations.The development of nickel titanium alloys and the possibility of changing the traditional design and taper have allowed use of rotary instruments in endodontic treatment. A new generation of NiTi rotary files has been introduced as the Protaper Next. Aim : The present study aimed to compare the instrumentation time and cleaning efficacy of Protaper Next with rotary Protaper Universal system and manual K file in pediatric endodontics. Materials and Methods: An in-vitro experimental study was conducted by injecting Indian ink in a total sample of 60 human single rooted primary anterior teeth. The teeth were randomly divided into three experimental groups, including K-file,ProTaper Universal, Protaper Next and one control group. The root canals were prepared using one of the three file system followed by clearing the teeth with different demineralising solutions.A chronometer was used to calculate the instrumentation time in each root canal and scores were analysed by a steremicroscope. Data analyses were performed using version 21.0 of Statistical Package for Social Sciences. Results: In the coronal third of root canals cleaning efficacy of K Files and ProTaper Next showed almost similar score.In the middle third of root canals cleaning efficacy scores in two file systems were significantly lower than K files . In the apical third ProTaper Next showed better cleaning efficacy compared to K files and ProTaper Universal Files systems. Difference between the different groups was statistically significant P=0.000(<0.001). Conclusion: This study showed that the use of Ni-Ti rotary instruments in the pulpectomy of primary anterior teeth represents a promising technique in pediatric patients, thus instrumentation is feasible, offeringtime-saving advantages in root canal preparation

AN in vitro study of 4 instruments in the preparation of curved root canals / 实用口腔医学杂志

Objective: To compare ProTaper Universal(PU),ProTaper Next(PN),WaveOne(WO) and M3 in the preparation of simulated curved canals. Methods: 40 simulated root canals were made from translucent resin and randomly divided into 4 groups(n = 10),the canals were prepared by PU,PN,WO and M3 respectively. The efficacy of canal preparation was analyzed. The pre-instrumentation and post-instrumentation images were recorded and the assessment of the canal shape was completed with Photoshop cs6 and Image Pro Plus6. 0. The apical transportation indexes and the amounts of apically extruded debris were measured. Results: WO was the most time-saving in mean working time(P ＜ 0. 05). PN and M3 took less time than PU in shaping the canals at the most levels(P ＜ 0. 05; PN vs M3,P＞ 0. 05). The amounts of apically extruded debris by PN was less than by PU,WO and M3(P ＜ 0. 05). The apical transportation by PN and M3 was less than that by PU and WO(P ＜ 0. 05). Conclusion: WaveOne is the most time-saving in shaping root canals. ProTaper Next and M3 are more effective and time-saving than ProTaper Universal in shaping root canals. ProTaper Next and M3 are comparable for optimally enlarge root canal.

Root canal volume change and transportation by Vortex Blue, ProTaper Next, and ProTaper Universal in curved root canals

OBJECTIVES: The aim of this study was to compare root canal volume change and canal transportation by Vortex Blue (VB; Dentsply Tulsa Dental Specialties), ProTaper Next (PTN; Dentsply Maillefer), and ProTaper Universal (PTU; Dentsply Maillefer) nickel-titanium rotary files in curved root canals. MATERIALS AND METHODS: Thirty canals with 20°–45° of curvature from extracted human molars were used. Root canal instrumentation was performed with VB, PTN, and PTU files up to #30.06, X3, and F3, respectively. Changes in root canal volume before and after the instrumentation, and the amount and direction of canal transportation at 1, 3, and 5 mm from the root apex were measured by using micro-computed tomography. Data of canal volume change were statistically analyzed using one-way analysis of variance and Tukey test, while data of amount and direction of transportation were analyzed using Kruskal-Wallis and Mann-Whitney U test. RESULTS: There were no significant differences among 3 groups in terms of canal volume change (p > 0.05). For the amount of transportation, PTN showed significantly less transportation than PTU at 3 mm level (p = 0.005). VB files showed no significant difference in canal transportation at all 3 levels with either PTN or PTU files. Also, VB files showed unique inward transportation tendency in the apical area. CONCLUSIONS: Other than PTN produced less amount of transportation than PTU at 3 mm level, all 3 file systems showed similar level of canal volume change and transportation, and VB file system could prepare the curved canals without significant shaping errors.

Automatic Electronic Device Used for the Evaluation of Cyclic-Fatigue Resistance of Nickel-Titanium Instruments

he aim of this study was to evaluate the cyclic-fatigue fracture of different Nickel-Titanium motor-driven rotary instruments (ProTaper® Universal, ProFile®, and Mtwo® systems) in artificial canals by means of an Automatic Electronic Device (AED). The study was performed using NickelTitanium instruments 25/0.06 evaluated in canals with a 45-degree curvature and 2-mm radius. The analyses evaluated two parameters: fracture by cyclic fatigue, and time of fracture; in addition, the length of separated fragment was evaluated. Medians and range values were calculated for each group. Data were analyzed by the Kruskall-Wallis and Mann-Whitney U tests to determine statistical difference. The ProFile motor-driven rotator system exhibited highest resistance to fracture due to cyclic fatigue and highest fracture time compared with the ProTaper and Mtwo systems (p <0.05). The equipment proposed in this study (AED) demonstrated efficiency for recording information, automation, scheduled work times and durations, cycle number, time of fracture, pressure changes and, principally control of the human factor.

l objetivo del presente estudio fue evaluar la fractura a la fatiga cíclica de diferentes instrumentos rotatorios de Niquel-Titanio (sistemas ProTaper® Universal, ProFile® y Mtwo®) en conductos artificiales por medio de un Dispositivo Electrónico Automático (DEA). Se usaron instrumentos de Niquel-Titanio 25/0.06, los cuales se evaluaron en conductos con una curvatura de 45 grados y 2 milímetros de radio. Se analizaron dos parámetros: Fractura a la fatiga cíclica y tiempo a la fractura; además se evaluó la longitud del fragmento separado. Medianas y rangos fueron calculados para cada uno de los grupos. Los resultados fueron analizados por las pruebas de Kruskall-Wallis y U de Mann-Whitney para determinar diferencias estadísticas. El Sistema ProFile mostró una mayor resistencia y tiempo a la fractura en comparación con los sistemas ProTaper y Mtwo (p <0.05). El equipo propuesto en este estudio (DEA) demostró eficiencia para el registro de la información, tiempos de trabajo y duración, número de ciclos, tiempo a la fractura, cambios en la presión y principalmente control del factor humano.

Evaluation of Effect of Hyflex EDM on Root Dentin during Root Canal Preparation-A Stereomicroscopic Study

Background: Root canal preparations done using many rotary endodontic instruments results in formation of root dentin defects because of the stress induced by the instruments within the root canal during cleaning and shaping, thereby worsening the long term prognosis of the root canal treated teeth. Many rotary instruments are been globally studied for the purpose of generating a correct instrument for root canal preparation. Objective: This study was done to evaluate the effect of HyFlex EDM, which is a new rotary system on root dentin during root canal preparation. Materials and methods: Fourteen single rooted premolars were selected and divided into two groups, Group 1-Protaper Universal and Group 2-HyFlex EDM. All the specimens were decoronated. Roots of each specimen were sectioned at 3mm, 6mm and 9mm and were then viewed under stereomicroscope for dentinal defects. t-test was done for the statistical analysis and level of significance was set at p=0.05. Results: Protaper Universal showed highest percentage of defect than HyFlex EDM. Conclusion: HyFlex EDM showed lowest percentage of defects in root dentin. Thus, HyFlex EDM is more efficient in root canal preparation than that of Protaper Universal thereby preventing dentinal defects or microcracks leading to root fractures.

Effect of adaptive motion on cyclic fatigue resistance of a nickel titanium instrument designed for retreatment

OBJECTIVES: The aim of this study was to evaluate the cyclic fatigue resistance of the ProTaper Universal D1 file (Dentsply Maillefer) under continuous and adaptive motion. MATERIALS AND METHODS: Forty ProTaper Universal D1 files were included in this study. The cyclic fatigue tests were performed using a dynamic cyclic fatigue testing device, which had an artificial stainless steel canal with a 60° angle of curvature and a 5 mm radius of curvature. The files were randomly divided into two groups (Group 1, Rotary motion; Group 2, Adaptive motion). The time to failure of the files were recorded in seconds. The number of cycles to failure (NCF) was calculated for each group. The data were statistically analyzed using Student's t-test. The statistical significant level was set at p < 0.05. RESULTS: The cyclic fatigue resistance of the adaptive motion group was significantly higher than the rotary motion group (p < 0.05). CONCLUSION: Within the limitations of the present study, the ‘Adaptive motion’ significantly increased the resistance of the ProTaper Universal D1 file to cyclic facture.

Cone-beam computed tomography analysis of the canal shaping ability with ProTaper Universal, ProTaper Next and M3 in preparation of curved root canals / 天津医药

Objective To evaluate the shaping ability of ProTaper Universal (PU), ProTaper Next (PN) and M3 in preparation of curved root canals by CBCT (cone-beam computed tomography). Methods Sixty extracted maxillary first premolars were divided into two groups according to the canal curvature:10°-25° group and 26°-75°group. Then, each group was divided into PU group, PN group and M3 group and prepared with three instruments respectively. Canals were scanned by CBCT scanner before and after preparation. The efficacy of canal preparation was analyzed. The width of dentine removed was measured at three points (2 mm, 5 mm and 8 mm to root tip). The apical transportation indexes and the centring ratio values were recorded. Results PN group and M3 group needed less time in preparation and showed more efficiency than those of PU group in 26°-75° groups. One of root canals in PU group appeared deformation, neither PN group nor M3 group appeared deformation after 5 root canal preparations in average. None instrument was broken in three groups. PU group removed more materials at internal walls than PN group and M3 group at internal walls of root canals in 5 mm from the apex. There was no difference in the offset of the external walls of root canals. Compared with the offset of the internal and external walls of root canals in 2 mm from the apex, the apical transportations prepared by the PN group were less than those of M3 group and PU group in 26°-75° groups. Compared with the offset of the internal and external walls of root canals in 5 mm from the apex, the apical transportations prepared by the PN group and M3 group were less than those of PU group, and their centring ratio values were greater than those of PU group in 26°-75°groups. Conclusion ProTaper Next and M3 tested in this study are effective and time-saving in shaping curved root canals. The results indicate that both ProTaper Next and M 3are comparable to optimally enlarge root canal.

On the Causality Between Dentinal Defects and Root Canal Preparation: A Micro-CT Assessment

Abstract This study aimed to evaluate the cause-effect relationship between canal preparation with ProTaper Universal (PTU) system and dentinal defects formation using micro-computed tomography (micro-CT) analysis. Forty mesial canals of mandibular molars with a type II Vertucci's canal configuration were scanned at an isotropic resolution of 14.16 µm. The sample was assigned to an experimental (n = 30) and a control (n = 10) groups, and the mesial canals were prepared with PTU system up to F2 instrument. The specimens from the experimental group were scanned and the cross-section images of the mesial roots, before and after preparation, were screened to identify the presence of dentinal defects. In the control group, the specimens were sectioned perpendicularly to the long axis of the root into 1-mm-thick slices (n = 80) and examined under optical microscope. Once a dentinal defect was detected, the slice was scanned through micro-CT. In the experimental group, dentinal micro-cracks were observed in 4,828 slices (24.04%). In all cross-section images, dentinal defects identified in the postoperative images were already present in the corresponding preoperative image. In the control group, 13 out of 80 slices (16.25%) had at least one dentinal defect visualized under stereomicroscopy, which was identified after a further micro-CT scanning. Micro-CT showed reliability as similar as optical microscopy in detecting dentinal defects, adding the possibility of tracking the dentinal tissue, before and after canal preparation, and providing a clear visualization of micro-cracks. Root canal preparation with PTU system did not induce the formation of new dentinal defects.

Resumo O objetivo deste estudo foi avaliar a relação de causa-efeito entre o preparo do canal radicular com o sistema ProTaper Universal (PTU) e a formação de defeitos dentinários usando a análise por micro-tomografia computadorizada (micro-CT). Quarenta raízes mesiais de molares inferiores com a configuração tipo II de Vertucci foram escaneadas com resolução isotrópica de 14.16 μm. A amostra foi distribuída em um grupo experimental (n = 30) e um grupo controle (n = 10), e os canais mesiais foram preparados com o sistema PTU até a lima F2. As amostras do grupo experimental foram escaneadas e as imagens de secção transversal das raízes mesiais, antes e após o preparo, foram analisadas ​​para identificar a presença de defeitos dentinários. No grupo controle, os dentes foram seccionados perpendicularmente em relação ao longo eixo da raiz em fatias de 1 mm de espessura (n = 80) e examinados ao microscópio óptico. Uma vez detectado um defeito dentinário, a fatia foi escaneada através da micro-CT. No grupo experimental, defeitos dentinários foram observados em 4.828 secções transversais (24,04%). Em todas as imagens de secção transversal, os defeitos dentinários após os procedimentos experimentais já estavam presentes na secção pré-operatória correspondente. No grupo controle, 13 das 80 fatias (16,25%) apresentaram pelo menos um defeito dentinário visualizado através do microscópio, o qual foi identificado em um escaneamento posterior. A micro-CT mostrou confiabilidade com a microscopia óptica para detecção e visualização dos defeitos dentinários, permitindo acompanhar o tecido dentinário antes e depois do preparo do canal. O preparo do canal radicular com o sistema PTU não induziu a formação de novos defeitos dentinários.

Eficiencia de tres técnicas en la remoción de gutapercha / Efficiency of three different techniques in the removal of gutta-percha

Cuando la terapia endodóntica fracasa, las opciones para solucionar este problema incluyen preservar el diente a través del retratamiento ortógrado o cirugía apical. Siempre que sea posible, el retratamiento endodóntico no quirúrgico debe ser la opción elegida. Diferentes sistemas rotatorios han sido propuestos como una alternativa a la instrumentación manual para la remoción de la gutapercha.El objetivo de este trabajo fue comparar la eficacia y la eficiencia en la desobturación total del canal radicular, utilizando dos tipos de instrumentos rotatorios: limas Protaper Universal® y limas Protaper Retratamiento® con limas manuales tipo K. Se instrumentaron 45 canales radiculares, con limas mecanizadas del sistema Mtwo®, hasta la 25/06 y terminados de conformar con lima K #40 e irrigados con hipoclorito de sodio al 2,5 % entre cada instrumento. Los dientes fueron obturados con técnica de condensación lateral, utilizando conos de gutapercha y cemento Tubliseal®.La muestra se dividió al azar en tres grupos A, B y C, de 15 canales cada uno, el grupo A se desobturó con limas Protaper Universal. El grupo B se desobturó con limas Protaper retratamiento y el grupo C se desobturó totalmente con limas K. Se cronometró cada procedimiento de desobturación y al término de esta, se tomó una radiografía en sentido buco-lingual y otra en sentido mesio-distal para cuantificar la remoción de gutapercha en cada grupo. Los resultados muestran que no existe diferencia significativa en la eliminación total del relleno endodóntico entre los tres grupos (p= 0,271) pero que los tiempos empleados en la desobturación total de los canales entre los grupos, muestra diferencias significativas entre Protaper Retratamiento y limas K, y entre Protaper Universal y limas K (p <0,05). Bajo las condiciones de este estudio, ningún sistema fue capaz de remover toda la gutapercha del interior del canal radicular.

When primary endodontic treatment fails, the treatment alternatives for root preservation are orthograde retreatment or apical surgery. Whenever possible, orthograde retreatment must be the first option. Different rotary systems have been proposed as an alternative to manual instrumentation for the removal of gutta-percha. The aim of this study was to compare the efficacy and efficiency of the total removal of gutta-percha from root canals, using two types of rotary instruments: Protaper Universal Files® and Protaper Retreatment Files®, compared to manual K type Files. A total of forty-five canals were instrumented with Mtwo files® up to a 25.06 file and the shaping was completed with a 40 K-type File and irrigated with 2.5 % Sodium Hypochlorite between each instrument. The teeth were obturated with Lateral Condensation Technique, using gutta-percha and Tubliseal® sealer. Samples were divided in groups A, B and C, 15 canals each, and gutta-percha was removed using the following protocols: group A with Protaper Universal; Group B using Protaper Retreatment and Group C using K type Files. Each procedure was timed and at the end of it, two periapical radiographs were taken: one buccolingual and one mesiodistal, in order to quantify the amount of gutta-percha removed. The results analysis show that there is no significant difference in the amount of gutta-percha removed between the three groups (p= 0.271) but that the time invested to perform the removal of the gutta-percha was significantly less between for the rotary systems, when compared to manual instrumentation (p <0.05). Under the conditions of this study, no system was able to remove all gutta percha inside the root canal.

Evaluación ex vivo del material de obturación extruido durante el retratamiento endodóntico con el empleo de dos técnicas de remoción / Ex vivo evaluation of the amount of extruded filling material during endodontic retreatment using wo removal techniques

Objetivo: evaluar ex vivo la cantidad de material de obturación durante el retratemiento endodóntico ortógrado con el uso de dos técnicas de desobturación. Materiales y métodos: se utilizaron 30 caninos humanos extraídos, de conducto único y raíces rectas. Los conductos se instrumentaron con ProGlider (Dentsply/Maillefer, Ballaigues, Suiza) y ProTaper Next X1, X2 y X3 (Dentsply/Maillefer, Ballaigues, Suiza) hasta la longitud de trabajo (LT), luego, se sobrepasó 1 mm del foramen apical con una lima tipo K #20. A continuación se obturaron con conocs de gutapercha ProTaper Next X3 (Dentsply / Maillefer, Ballaigues, Suiza), condensación lateral y termocompactación. Como sellador endodóntico, se utilizó el AHPlus (Dentsply DeTrey, Konstanz, Alemania), coloreado con tinta china azul. Los especímenes se dividieron aleatoriamente en dos grupos de 15 dientes. Las raíces se montaron en tubos Eppendorf, que fueron pesados previamente en una balanza de precisión. En el grupo 1 (n=15) se removió la gutapercha con instrumentos D1, D2 del sistema ProTaper Universal, hasta el tercio medio y luego hasta la LT con D3 y limas Hedstroem #40 (Dentsply/Maillefer, Ballaigues, Suiza), empleando xilol. La remoción se completó con ProTaper Next x4 hasta la LT. En el grupo 2 (n=15) se removió la gutapercha con el sistema ProTaper Universal D1, D2 y D3 hasta el tercio apical y se completó con ProTaper Next x4 hasta la LT. En ambos grupos se realizaron lavajes con 3 ml de agua destilada a cada cambio de instrumento y al finalizar la instrumentación. Se retiraron las tapas con los especímenes de los tubos Eppendorf, los cuales fueron colocados en una estufa de cultivo a 27ºC durante 5 días. Los tuvos se pesaron nuevamente (sin sus tapas) para determinar la diferencia de peso correspondiente al material de obturación extravasado. La comparación de las diferencias de peso promedio entre los dos grupos se realizó mediante la prueba no paramétrica de Mann-Whitney.

Shaping ability of ProTaper Gold and ProTaper Universal files by using cone‑beam computed tomography.

Context: This study evaluated and compared the shaping ability of ProTaper Gold (PG) (PG; Dentsply, Tulsa Dental Specialties, Tulsa, OK, USA) system with ProTaper Universal (PU) (PU; Dentsply Maillefer, Ballaigues, Switzerland) using cone‑beam computed tomography (CBCT) imaging. Materials and Methods: Forty mesiobuccal canals of mandibular first molars with curvatures of 25−30° were divided into two experimental groups (n = 20) according to the rotary nickel–titanium (NiTi) file system used in canal instrumentation as follows: Group PG and group PU. Canals were scanned before and after instrumentation using CBCT scanner to evaluate root canal transportation and centering ratio at 3, 5, and 7 mm from the apex and volumetric changes. Data were statistically analyzed using independent t‑tests and the significance level was set at P < 0.05. Results: There was no significant difference between PG and PU systems in the mean volume of removed dentine, canal transportation, and centering ratio (P > 0.05). Conclusions: The PG and PU NiTi rotary systems showed similar root canal shaping abilities in the preparation of mesial canals of mandibular first molars.

Influence of Apical Patency and Cleaning of the Apical Foramen on Periapical Extrusion in Retreatment

This study evaluated the influence of apical patency, root filling removal technique and cleaning of the apical foramen, concerning the amount of debris extruded during root canal retreatment. Forty mandibular incisors were randomly assigned to 4 groups - GIM (n=10), GIIM (n=10), GIPT (n=10) and GIIPT (n=10), which were named according to leaving (I) or not (II) apical patency during canal preparation and filling removal technique (manual - M or ProTaper system - PT). After filling material removal, each specimen of each group had the apical foramen cleaned by sizes 15, 20 and 25 instruments, generating 12 subgroups: GIM15, GIM20, GIM25, GIIM15, GIIM20, GIIM25, GIPT15, GIPT20, GIPT25, GIIPT15, GIIPT20 and GIIPT25. Extruded filling debris was collected by a Milipore filtration system, an HV-durapore, 0.45 µm pore filter with a 25 mm diameter. The filters were weighed before and after the collection on an analytical scale (10–5 g), and the difference was calculated. The mean weight of extruded filling debris was analyzed statistically by Kruskal-Wallis and Friedman ANOVA tests (α=0.05). The mean values found in the groups (in mg) were: GIM (0.95±0.94), GIIM (0.47±0.62), GIPT (0.30±0.31) and GIIPT (0.32±0.44). There was no statistically significant difference among any of the groups or subgroups (p>0.05). ProTaper provided the smallest amount of extruded filling material, regardless of presence or absence of apical patency, followed by manual technique, without and with apical patency. Additional amounts of debris were collected during cleaning of the apical foramen, regardless of the instrument, presence/absence of patency or root filling removal technique.

Este estudo verificou a influência da patência apical, técnica de desobturação e limpeza foraminal na quantidade de material sólido extruído, durante retratamento endodôntico. Quarenta incisivos inferiores foram divididos aleatoriamente em quatro grupos - GIM (n=10), GIIM (n=10), GIPT (n=10) e GIIPT (n=10) - nomeados de acordo com a realização (I) ou não (II) de patência apical durante o preparo de canais e a técnica de desobturação - manual (M) ou sistema ProTaper (PT). Após a desobturação, realizou-se a limpeza foraminal em cada espécime de todos os grupos com instrumentos #15, #20 e #25, gerando 12 subgrupos: GIM15, GIM20, GIM25, GIIM15, GIIM20, GIIM25, GIPT15, GIPT20, GIPT25, GIIPT15, GIIPT20 e GIIPT25. O material sólido extruído foi coletado pelo sistema de filtração Millipore®, com filtros de 0,45 µm de poro e 25 mm de diâmetro. Os filtros foram pesados antes e após a coleta, em balança analítica de precisão (10–5g), e as diferenças foram calculadas. Os valores médios encontrados (em mg) foram: GIM (0,95±0,94), GIIM (0,47±0,62), GIPT (0,30±0,31) e GIIPT (0,32±0,44), sem diferença estatística entre quaisquer dos grupos ou subgrupos (p>0,05). O sistema Protaper proporcionou a menor quantidade de material sólido extruído, independente da presença ou não de patência apical seguidos da técnica manual sem e com patência apical. Quantidades adicionais foram coletadas durante a limpeza foraminal, independente do instrumento utilizado, da presença ou não da patência apical ou da técnica de desobturação.

Instrumentación rotatoria en endodoncia: reporte de casos clínicos / Rotary instrumentation in endodontics: clinical cases report

Los recientes avances en endodoncia de los últimos años, como la introducción de instrumentación rotatoria con limas de Niquel Titanio (NiTi), han simplificado el proceso del tratamiento, mejorando el éxito a largo plazo en términos de tiempo, efectividad y reducción de riesgos, comparados con la instrumentación manual con limas de acero inoxidable. Sin embargo, para algunos clínicos resulta difícil seleccionar el sistema rotatorio NiTi más apropiado, debido a la numerosa cantidad de instrumentos que conforman los diferentes sistemas existentes en el mercado. El presente reporte, basado en casos clínicos de la práctica diaria, tiene como objetivo mostrar, analizar y destacar la posibilidad de realizar tratamientos endodónticos predecibles con la técnica corono apical utilizando el sistema ProTaper Universal.

Advances in recent years in endodontics, such introduction of rotary Niquel Titanium (NiTi) instrumentation have simplified the treatment process and improved the long term success in terms of procedural time, accuracy, and risk reduction compared with the previously used, manual, stainless steel files. However, selecting the most appropriate NiTi system remains difficult for clinicians because of the large number of NiTi rotary instruments available nowadays on the market. This paper aims to show, analyze and emphasize, on the basis of every day clinical practice, the possibility of realizing predictability root canal preparations with the crown down technique of ProTaper Universal system.

Comparison of the centering ability of the ProTaper Universal, ProFile and Twisted File Rotary Systems

Aim: To determine the centering ability of Twisted File™ rotary system compared with ProTaperUniversal™ and ProFile™ rotary systems by evaluating pre- and postoperative cross-sectionalimages of the apical root canals third. Methods: Thirty mesiobuccal canals of human mandibularfirst molars were divided into three groups with 10 root canals each according to the instrumentused: group 1, ProTaper Universal™ rotary system; group 2, ProFile™, and group 3, TwistedFile™. Pre- and postoperative images of the apical thirds were viewed with a stereoscopicmagnifier with ×10 magnification and were captured digitally for further analysis using the ImageTools Software. The results were analyzed statistically by the Kruskal-Wallis test and the Mann-Whitney test. A level of significance of 0.05 was adopted. Results: The means of the buccolingualmeasurement ranged from 0.79 to 1.5. The largest deviation was registered to instrument 25.06in group 2. The means of the mesiodistal measurement ranged from 0.86 to 1.52, with the largestdeviation being registered to instrument 25.04 in group 3; however, there were no statisticallysignificant differences (p>0.05) among the three groups or among the instruments in the samegroup in terms of centering ability. Conclusions: None of the rotary systems evaluated in thisstudy was totally effective in performing biomechanical preparation of the root canals.

Comparison of root canals obturated with ProTaper gutta-percha master point using the active lateral condensation and the single-cone techniques: a bacterial leakage study

Aim: The aim of the present study was to assess the recontamination time of root canals filled with ProTaper gutta-percha master point using the active lateral condensation and the single-cone techniques. Methods: Fifty premolars, after biomechanical preparation, were randomly divided into six groups according to the obturation technique and the diameter of the gutta-percha point. For leakage evaluation, the roots were mounted in a dual-chamber leakage model system using Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli, and Staphylococcus aureus. The Kaplan-Meier and Long-Rank tests were employed at the .05 level of significance. Results: The recontamination was detected between the 13th and 80th days. The active lateral condensation produced less infiltration than the single cone technique, though without statistically significant differences between them. Conclusions: It may be concluded that there was no difference in bacterial penetration between the two root canal filling techniques. The mean root canalcontamination time was 67 days.

Antimicrobial activity of chlorhexidine in root canals instrumented with the ProTaper Universal™ System

Aim: The purpose of the present study was to evaluate the antimicrobial activity of 0.2%, 1%, and2% chlorhexidine in root canals instrumented with the ProTaper Universal™ system. Methods:Fifty human mandibular premolar teeth were infected with a mixture of Candida albicans,Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus. The specimens were randomly divided into 5 groups with 10 root canals according to the irrigant used. All root canals were instrumented with the ProTaper Universal™ system. Assessment of the antimicrobial action of the irrigant was performed before, during, and after instrumentation. Data were analyzed statistically by Chi-squared test and the Fisher exact test at 5% significance level. Results: The0.2% chlorhexidine solution was ineffective against all test microorganisms. The 1% chlorhexidinesolution was effective in eliminating P. aeruginosa and C. albicans after the use of the F1 and F3instruments, respectively. The 2% chlorhexidine solution was effective at killing S. aureus, P.aeruginosa and C. albicans after the use of the S1 instrument. There were statistically significant differences (p<0.05) between the concentrations of chlorhexidine and the instruments used.Conclusions: The 0.2% chlorhexidine solution in combination with rotary instrumentation was ineffective against all test microorganisms. The 1% chlorhexidine solution was ineffective against S. aureus and E. faecalis. The 2% chlorhexidine solution was not sufficient to inactivate E.faecalis.

Assessment of canal walls after biomechanical preparation of root canals instrumented with protaper universalTM rotary system

OBJECTIVE: The aim of this study was to examine the instrumented walls of root canals prepared with the ProTaper UniversalTM rotary system. MATERIAL AND METHODS: Twenty mesiobuccal canals of human first mandibular molars were divided into 2 groups of 10 specimens each and embedded in a muffle system. The root canals were transversely sectioned 3 mm short of the apex before preparation and remounted in their molds. All root canals were prepared with ProTaper UniversalTM rotary system or with NitiflexTM files. The pre and postoperative images of the apical thirds viewed with a stereoscopic magnifier (X45) were captured digitally for further analysis. Data were analyzed statistically by Fisher's exact test and Chi-square test at 5 percent significance level. RESULTS: The differences observed between the instrumented and the noninstrumented walls were not statistically significant (p<0.05). CONCLUSIONS: The NitiflexTM files and the ProTaper UniversalTM rotary system failed to instrument all the root canal walls.