Apical extrusion of bacteria following the use of reciprocating single-file and rotary multi-file instrumentation systems in oval root canals / Extrusão apical de bactérias após o uso de sistemas alternativos de instrumentação de arquivo único e rotativo de arquivo múltiplo em canais radiculares ovais

Objective: All instrumentation techniques and instruments are associated with apical extrusion during chemomechanical preparation, and this causes postoperative pain and flare-up. However, it is controversial whether reciprocal systems or rotary systems cause more apical extrusion. The objective of this in vitro study was to determine the differences in the amounts of apically extruded bacteria (AEB) associated with nickel-titanium rotary and reciprocating systems when used in oval-shaped root canals. Material and Methods: Seventy human mandibular premolar teeth with oval-shaped canals were randomly assigned to four experimental groups (15 teeth in each group) and one control group (10 teeth). The root canals were contaminated with Enterococcus faecalis and instrumented using two full-sequence rotary instruments (ProTaper Universal [PTU] and ProTaper Next [PTN]) and two reciprocating single-file instruments (Reciproc [R] and WaveOne [WO]). A 0.9% NaCl solution was used as an irrigant, and the bacterial extrusion was quantified as the number of colony-forming units for each sample. The results were statistically analyzed using the Kruskal-Wallis one-way analysis of variance and the Mann-Whitney U test, and the statistical significance level was set at p < 0.05. Results: The R system was associated with the highest amount of bacterial extrusion (p < 0.05). The PTU system caused more bacterial extrusion than the PTN and WO systems (p < 0.05). There was no significant difference between the PTN and WO systems (p > 0.05). Conclusions: All instrumentation techniques caused apical bacterial extrusion. The instrument design and preparation techniques affect the number of extruded bacteria (AU)

Objetivo: Todas as técnicas e instrumentos de instrumentação estão associados à extrusão apical durante o preparo quimomecânico, o que causa dor e surto no pós-operatório. No entanto, é controverso se sistemas recíprocos ou rotativos causam extrusão mais apical. O objetivo deste estudo in vitro foi determinar as diferenças na quantidade de bactérias apicalmente extrudadas (AEB) associadas aos sistemas rotativo e alternativo de níquel-titânio quando usadas em canais radiculares em forma oval. Material e Métodos: Setenta dentes pré-molares inferiores humanos com canais em forma oval foram divididos aleatoriamente em quatro grupos experimentais (15 dentes em cada grupo) e um grupo controle (10 dentes). Os canais radiculares foram contaminados com Enterococcus faecalise instrumentados usando dois instrumentos rotativos de seqüência completa (ProTaper Universal [PTU] e ProTaper Next [PTN]) e dois instrumentos alternativos de arquivo único (Reciproc [R] e WaveOne [WO]). Uma solução de NaCl a 0,9% foi usada como irrigante e a extrusão bacteriana foi quantificada como o número de unidades formadoras de colônias para cada amostra. Os resultados foram analisados estatisticamente usando a análise de variância unidirecional de Kruskal-Wallis e o teste U de Mann-Whitney, e o nível de significância estatística foi estabelecido em p < 0,05. Resultados: O sistema R foi associado à maior quantidade de extrusão bacteriana (p < 0,05). O sistema PTU causou mais extrusão bacteriana que os sistemas PTN e WO (p < 0,05). Não houve diferença significativa entre os sistemas PTN e WO (p > 0,05). Conclusões: Todas as técnicas de instrumentação causaram extrusão bacteriana apical. O desenho do instrumento e as técnica (AU)

Extrusión Apical de Barro Dentinario e Irrigante Producidos por Dos Sistemas de Instrumentación de Níquel Titanio al Utilizar Irrigación Pasiva o Activa / Apical Extrusion of Dentin and Irrigant Smear Layer Produced by Two Nickel Titanium Instrumentation Systems when Using Passive or Active Irrigation

RESUMEN: El barro dentinario producido durante tratamiento endodóntico puede ser extruido hacia el tejido periradicular junto con el irrigante, produciendo inflamación y dolor postoperatorio. Comparar la cantidad de extrusión apical de barro dentinario e irrigante, producido durante la preparación químico-mecánica, por dos sistemas de instrumentación Rotatoria (Mtwo), y Reciprocante (Reciproc), complementado con irrigación pasiva o activa (Endoactivator). Cuarenta y ocho premolares (48) inferiores, fueron aleatoriamente distribuidos en cuatro grupos de estudio (n=12 dientes), (1) Rotatorio-pasiva, (2) Reciprocante-pasiva, (3) Rotatorio-activa y (4) Reciprocante-activa. Los conductos radiculares fueron instrumentados de acuerdo a las instrucciones del fabricante, e irrigados con hipoclorito de sodio al 5 %. El barro dentinario e irrigante extruido, fueron recolectados en tubos Eppendorf previamente pesados. Se calcularon los valores de extrusión de barro dentinario e irrigante para cada grupo. Los datos fueron analizados con el análisis de varianza ANOVA. En todos los grupos se produjo extrusión apical. No se encontraron diferencias estadísticamente significativas en la extrusión apical de barro dentinario, entre los grupos estudiados (P = 0,068), sin embargo, al analizar la extrusión de irrigantes, se evidenció diferencia estadísticamente significativa entre los grupos 1 y 4 (P< 0,05), entre los demás grupos no se observaron diferencias estadísticamente significativas. (P > 0,05). Bajo las condiciones de este estudio, los sistemas rotarios y reciprocante, extruyen sólido y líquido, siendo el sistema reciprocante el que produce mayor extrusión de líquido, tanto con irrigación activa como pasiva.

ABSTRACT: The smear layer produced during endodontic treatment can be extruded into the periradicular tissue together with the irrigant, producing inflammation and postoperative pain. The purpose of this in vitro study was to compare the amount of apical extrusion, produced during the endodontic preparations with two rotary instrumentation systems using passive and active irrigation. Forty-eight (48) mandibular premolars were randomly assigned to 4 groups (n = 12 teeth), (1) Rotatory - passive, (2) Reciprocating passive, (3) Rotatory-active, (4) Reciprocating- active. The root canals were instrumented according to the manufacturer's instructions and irrigated with 5 % sodium hypochlorite. Extruded debris and irrigant were collected in previously weighed Eppendorf tubes. The extrusion values were calculated for each group. The data were analyzed with the ANOVA analysis of variance. Results: Apical extrusion was produced in all groups. No statistically significant differences were found in the apical extrusion of smear layer, between the groups studied (P = 0.068), however, when analyzing the extrusion of irrigants, a statistically significant difference was evidenced between groups 1 and 4 (P <0.05). , among the other groups no statistically significant differences were observed. (P> 0.05). Under the conditions of this study, the reciprocating and rotary systems, extrude solid and liquid, being the reciprocating system the one that produces more extrusion of liquid, with both active and passive irrigation.

Evaluation of Apically Extruded Debris and Irrigants during Root Canal Preparation using Different Rotary Instrumentation Systems: An In-vitro Comparative Study

Background: Different instrumentation systems and techniques are used in the instrumentation of the root canal system which can result in debris formation that may be extruded beyond the apical foramen and cause post-operative pain. Aim of the study: Aim of the current study was to compare the amount of apically extruded debris and irrigants during instrumentation using 2 reciprocating single file systems (WaveOne Gold, Reciproc blue) and 2 continuous rotation file systems (ProTaper Gold, 2Shape) and comparing them to the control group (ProTaper Universal). Materials and Methods: Total 50 palatal roots of freshly extracted human maxillary first molars were collected for this study. Teeth were decoronated to a unified length of 15 mm, and then pushed through a pre-perforated rubber cap of pre-weighed glass vial then the root-cap complex was fitted on a glass vial and rubber dam ligated with dental floss was used to cover the glass vial for preventing the coronally extruded debris and irrigants from contaminating the external surface, gauge 25 needle was inserted parallel to the root surface through the rubber dam and cup. Samples were then randomly divided into 5 groups. Results: Data obtained were statistically analyzed using One Way ANOVA and LSD tests. The result showed that all groups resulted in apical extrusion of debris and irrigants, as it showed that the 2Shape Group B, Wave One Gold Group C and Reciproc blue Group D are statistically comparable, while ProTaper Gold Group A and ProTaper Universal Groups E showed statistically significant difference (p<0.05). Conclusions: All of the systems resulted in apical extrusion. There was no influence of kinematic movements on apical extrusion. The 2shape file system produced the least amount of apical extrusion while the ProTaper Universal showed the greatest amount.

A comparison of the effect of different nickel-titanium instruments combined with ultrasonic irrigation on root canal preparation / 口腔疾病防治

Objective @#To compare the removal efficiency and the amounts of apically extruded debris using Twisted File (TF), Twisted File Adaptive (TFA), ProTaper, and ProTaper Next combined with ultrasonic irrigation and to provide an experimental basis for the selection of root canal instrumentation in the clinic.@*Methods@#Forty mandibular premolars were randomly divided into 4 groups (n=10 teeth per group). The canals were cut using a Twisted File, Twisted File Adaptive, ProTaper, or ProTaper Next nickel-titanium instrument. The canals were irrigated with ultrasonic irrigation. The apically extruded debris were collected in preweighted Eppendorf tubes. The amount of dental tissue removed and extruded debris were assessed with an electronic balance.@*Results @#The amount of tooth tissue removed in groups A, B, C and D was 20.5 ± 2.0 mg, 17.8 ± 4.2 mg, 20.8 ± 3.9 mg and 16.5 ± 2.2 mg, respectively. Combined with ultrasonic irrigation, the Twisted File and ProTaper had a better removal efficiency than the ProTaper Next(P < 0.05). There was no significant difference in the amount of extruded debris (χ2=4.057, P=0.255) among four groups.@*Conclusion@#The Twisted File and ProTaper had a better removal efficiency than the ProTaper Next combined with ultrasonic irrigation. There was no significant difference in the amount of extruded debris using four Nickel-titanium instruments combined with ultrasonic irrigation.

Evaluation of apically extruded debris using continuous rotation, reciprocation, or adaptive motion

Abstract The aim of this study was to compare the amount of apically extruded debris during root canal instrumentation using ProTaper Next (PTN), Twisted File (TF) Adaptive, and Reciproc instruments. Forty-five extracted human maxillary canines were selected and randomly assigned into 3 groups. The root canals were prepared using PTN instruments with continuous rotation (n=15), TF Adaptive instruments with adaptive motion (n=15), Reciproc instruments with reciprocating motion (n=15). During the preparations, canals were irrigated using distilled water and material extruded apically was collected in pre-weighed Eppendorf tubes. After a 5-day drying period in an incubator, the tubes were weighed and the dry weight of the extruded debris was calculated. Data distributions were assessed via the Shapiro-Wilk test, and groups were compared via the Kruskal-Wallis test. The greatest amount of debris extruded by TF Adaptive and the least by PTN, but the difference was insignificant between groups (p=0.259). All instrumentation systems were associated with debris extrusion.

Resumo O objetivo deste estudo foi comparar a quantidade de detritos apicalmente extruídos durante a instrumentação do canal radicular usando os instrumentos ProTaper Next (PTN), Twisted File (TF) Adaptative e Reciproc. Quarenta e cinco caninos superiores humanos extraídos foram selecionados e distribuídos aleatoriamente em 3 grupos. Os canais radiculares foram preparados utilizando instrumentos PTN com rotação contínua (n = 15), instrumentos TF Adaptative com movimento adaptativo (n = 15), instrumentos Reciproc com movimento oscilatório (n = 15). Durante os preparos, os canais foram irrigados com água destilada e o material extruído foi coletado apicalmente em tubos Eppendorf pré-pesados. Após um período de secagem de 5 dias numa incubadora, os tubos foram pesados e o peso seco dos resíduos extruídos foi calculado. A distribuição dos dados foi avaliada pelo teste de Shapiro-Wilk e os grupos foram comparados pelo teste de Kruskal-Wallis. A maior quantidade de detritos extruídos foi proporcionada pelo TF Adaptive e a menor pelo PTN, mas a diferença não foi estatisticamente significante entre os grupos (p=0,259). Todos os sistemas de instrumentação promoveram extrusão de detritos apicalmente.

Apically extruded debris in filling removal of curved canals using 3 NiTi systems and hand files

Abstract The aim of this study was to assess the amount of apically extruded debris during filling removal with WaveOne Gold (WOG), ProTaper Universal Retreatment (PTR), D-RaCe Retreatment (DRR) or hand files (HF), to compare the working time during filling removal, and to describe failures of NiTi instruments. Forty mesiobuccal roots of maxillary first molars were prepared with WOG Primary, obturated and divided into 4 groups (n=10), according to the instruments used: WOG, PTR, DRR or HF. Distilled water was used as irrigant and the extruded debris were collected in Eppendorf tubes and dried. The amount of extruded debris was determined by subtracting the final from the initial weight. The time of filling removal for each canal was recorded and the instruments used were analyzed pre and post-operatively by SEM. Kruskal-Wallis and Dunn's test analyzed extruded debris data and ANOVA, followed by Tukey's test, compared the working time data (a=0.05). Instrument deformation and fracture were described. WOG produced significantly less debris compared with HF and DRR (p<0.05), and similar to PTR (p>0.05). HF, PTR and DRR showed no significant difference (p>0.05). Working time in HF group was significantly higher than others (p<0.05). SEM analyses showed, from the 18 instruments evaluated, 3 fractures and 10 deformations. All instruments tested caused debris extrusion. WOG was associated with less extrusion than DRR and HF. Filling removal with HF was slower than with the other instruments. All NiTi systems presented fracture and deformation.

Resumo O objetivo deste estudo foi avaliar a extrusão apical de debris durante a desobturação com WaveOne Gold (WOG), ProTaper Universal Retratamento (PTR), D-RaCe (DRR) ou limas manuais (HF), comparar o tempo de trabalho durante a desobturação, e descrever as falhas dos instrumentos de NiTi. Quarenta canais de raízes mésio-vestibulares de primeiros molars superiores foram preparados com WOG Primary, obturados e divididos em 4 grupos (n = 10), de acordo com os instrumentos a serem utilizados: WOG, PTR, DRR ou HF. Água destilada foi utilizada como irrigante, e os debris extruídos foram coletados em tubos Eppendorf e secos. A quantidade de debris extruídos foi determinada subtraindo-se o peso inicial do peso final. O tempo de cada desobturação foi anotado e os instrumentos utilizados foram analisados no pré e pós-operatório em MEV. Os testes Kruskal-Wallis e Dunn foram utilizados para analisar os dados da extrusão de debris, e os testes ANOVA e Tukey para comparar os dados do tempo de trabalho (a=0.05). As deformações e fraturas dos instrumentos foram descritas. O grupo WOG produziu significativamente menos debris quando comparado aos grupos HF e DRR (p<0.05), e foi similar ao grupo PTR (p>0.05). Os grupos HF, PTR e DRR não apresentaram diferença estatisticamente significante (p>0.05). O tempo de trabalho no grupo HF foi significativamente maior do que nos outros grupos (p<0.05). A análise em MEV mostrou que, dos 18 instrumentos avaliados, 3 fraturaram e em 10 foi observado deformação. Todos os sistemas testados causaram extrusão apical de debris. WOG foi associado com menor extrusão do que DRR e HF. A desobturação com HF foi mais lenta do que com os demais instrumentos. Todos os sistemas de NITI apresentaram fratura e deformação.

Micro-computed tomographic evaluation of removal and extrusion of root filling material during canal retreatment / Avaliação por meio de microtomografia computadorizada da remoção e extrusão de material obturador durante retratamento endodôntico

This study aimed to assess the efficiency of manual and rotary techniques for removing root filling material in endodontic treated canals and to evaluate the extrusion of debris via apical foramen. After access preparation, thirty human lower central incisors were instrumented, filled and divided into two groups (n=15): MNmanual retreatment technique; RT- rotary retreatment technique. The teeth were submitted to micro-computed tomographic scanning before and after the retreatment procedure, for quantifying the remaining filling material by relating the initial and final conditions. The analysis was conducted separately in all root thirds. The volume of material extruded through the apical foramen was also quantified. The data were statistically analyzed using t-test and two-way analysis of variance (ANOVA) at 5% of significance. No significant differences were detected between remaining filling material for the techniques evaluated (p=0.74), even considering the apical third only (p>0.75). Significant differences were found for the remaining filling material verified between the cervical third and middle/apical thirds, with lower values being observed at the cervical third for both groups (p<0.05). Apical extrusion of filling material was verified in seven specimens (2 from MN group and 5 from RT group). Both techniques showed similar performance for removing filling material from the root canal, considering the whole tooth or the root thirds independently. The apical extrusion of filling material observed was not sufficient to indicate which technique has increased tendency to induce more events during retreatments.

Este estudo objetivou avaliar a eficiência das técnicas manual e rotatória na remoção de material obturador de dentes tratados endodonticamente, além de verificar a extrusão de resíduos via forame apical. Após acesso endodôntico, trinta incisivos centrais inferiores humanos foram instrumentados, obturados e divididos em dois grupos (n=15): MN- técnica de retratamento manual; RT- técnica de retratamento rotatória. Os dentes foram submetidos à escaneamento micro-tomográfico previamente e após os procedimentos de retratamento para quantificação do remanescente de material obturador relacionando as condições inicial e final. Esta análise foi conduzida separadamente em todos os terços radiculares. O volume de material extruído via forame apical também foi quantificado. Os dados foram analisados estatisticamente por meio dos Testes T e de Análise de Variância em dois níveis com significância em 5%. Diferenças significantes não foram detectadas entre a quantidade de material remanescente para as duas técnicas avaliadas (p=0,74), mesmo considerando o terço apical separadamente (p>0.75). Diferenças significantes foram encontradas na quantidade de material remanescente verificado entre os terços cervical e médio/apical, com menores valores detectados no terço cervical para ambos os grupos (p<0.05). Extrusão apical de material obturador foi identificada em sete espécimes (2 do grupo MN e 5 do grupo RT). As duas técnicas avaliadas apresentaram desempenho similar na remoção do material obturador do canal radicular, considerando o dente como um todo ou os terços radiculares separadamente. A extrusão apical de material obturador verificada não foi suficiente para indicar qual técnica possui maior tendência de promover eventos durante o retratamento.

Apical Extrusion of Debris and Irrigants Using Different Irrigation Needles

Abstract This study evaluated the influence of irrigation tip, root canal curvature and final apical diameter on periapical debris and irrigant extrusion during root canal instrumentation. After being classified as mildly or moderately curved, the mesiobuccal root canals of 90 human molars were instrumented. The teeth were allocated into three groups according to the used needle type: a flat open-end needle (Group 1), a side-vented needle (Group 2) or a double side-vented needle (Group 3). The amount of extruded material after instrumentation was calculated for each group. The differences in irrigant and debris extrusion between the experimental groups were analyzed with the Mann-Whitney U test. Irrigation tips and final instrument diameter differences were analyzed with the Kruskal-Wallis test. Multiple groups were compared using the Mann-Whitney U-test with a Bonferroni correction at α=0.05. The amount of extruded material from the double side-vented needle was significantly less than the open-ended flat needle (p=0.008), but there was no difference compared to the side-vented needle (p=0.929). The results showed no effect of root curvature and final apical diameter on the amount of irrigant and debris extrusion (p>0.05). The double side-vented needles generated the least material extrusion to the periapical tissues. Irrigation needle type had the greatest influence on periapical irrigant and debris extrusion and the double side-vented needles may be safely used during endodontic therapy.

Resumo Este estudo avaliou a influência do tipo de agulha de irrigação, curvatura do canal radicular e diâmetro apical final sobre a extrusão de detritos e solução irrigadora durante o preparo físico-químico do canal radicular. O canal mésio- vestibular de 90 molares foi instrumentado, após ser classificado como de curvatura leve ou moderada. Os dentes foram divididos de acordo com o tipo de agulha utilizada em 3 grupos: agulha de extremidade aberta (Grupo 1), agulha de extremidade fechada com abertura lateral (Grupo 2) ou agulha de extremidade fechada com dupla abertura lateral (Grupo 3). A quantidade de material extruído após a instrumentação foi calculada em cada grupo. As diferenças de extrusão de solução irrigadora e detritos entre os grupos experimentais foram analisados com o teste de Mann-Whitney. As diferenças entre o tipo de agulha de irrigação e o diâmetro apical final foram analisados com o teste de Kruskal-Wallis. Grupos múltiplos foram comparados usando o teste U de Mann-Whitney com correção de Bonferroni em α= 0,05. A quantidade de material extruído pela agulha de extremidade fechada com dupla abertura lateral foi significativamente menor do que a agulha de extremidade aberta (p = 0,008), porém não houve diferença em relação a agulha de extremidade fechada com abertura lateral (p = 0,929). Os resultados não indicaram relação entre a curvatura radicular e o diâmetro apical final sobre a quantidade de solução irrigante e detritos de extruídos (p> 0,05). O uso de agulhas com dupla abertura lateral resultaram em uma menor extrusão de material aos tecidos periapicais. O tipo de agulha de irrigação teve a maior influência sobre extrusão periapical de solução irrigadora e detritos. As agulhas de extremidade fechada com dupla abertura lateral podem ser utilizadas com segurança durante a terapia endodôntica.

Análisis descriptivo de tamaño, forma y disposición de las virutas dentinarias producidas por la instrumentación manual y por diferentes sistemas de instrumentación mecanizada / A descriptive analyisis of the size, shape and disposition of dentin chips produced by manual instrumentation and different mechanical instrumentation systems

Objetivo: evaluar "ex vivo" el tamaño, la forma y la disposición de las virutas dentinarias generadas por la instrumentación manual y por distintos sistemas mecanizados de preparación endodóntica. Materiales y métodos: se utilizaron 25 dientes humanos unirradiculares, con ápice maduroy un único conducto radicular. Luego de realizar la apertura coronaria de forma convencional, se determinó la longitud de trabajo de cada diente mediante la introducción de una lima tipo K Nº 10 en el conducto radicular hasta visualizarla en el foramen apical. A la medida obtenida se le restaron 3 mm y se seccionnó esa porción apical con un disco de diamante. A continuación, se irrigaron los conductos con una solución de NaOCl al 2,5% y se secaron con conos de papel absorbente. Los especímenes fueron divididos aleatoriamente en cinco grupos de 5 dientes, y para cada grupo se usó un sistema de instrumentación diferente: grupo 1, HyFlex CM 40/0.04 (Coltene ENDO, Ohio, Estados Unidos); grupo 2, WaveOne Large (Dentsply-Maillefer, Ballaigues, Suiza); grupo 3, ProTaper Next X4 (Dentsply-Maillefer); grupo 4, lima manual tipo K Nº 40 (Dentsply-Maillefer); grupo 5, Reciproc R40 (VDW, Munich, Alemania). Cada uno de los dientes fue insertado hasta su tercio cervical en la tapa de un tubo Eppendorf, a fin de recolectar las partículas de dentina producidas durante la instrumentación. Se seleccionaron, de manera aleatoria, dos tubos con muestras por cada grupo de estudio. A continuación, cada muestra se colocó en un portaobjetos y se observó en un microscopio Leica DM2000 (Leica Microsystems, Wetzlar, Alemania) a fin de evaluar tamaño, forma y disposición de las partículas de dentina obtenidas. Resultados: las partículas de dentina presentaron tamaños variables; la de mayor tamaño fue de 112 um x 35 um; la de menor tamaño, de 23 um x 10 um. La forma que predominó fue la rectangular. En general, la disposición fue regular, excepto en el caso de la instrumentación manual con limas tipo K.

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.

Influence of apical enlargement in cleaning and extrusion in canals with mild and moderate curvatures

Optical microscopy and morphometric analysis were used in this study to evaluate, in vitro, the cleaning of the apical region in root canals with mild or moderate curvatures subjected to biomechanical preparation with a rotary system, as well as to assess the amount of extruded material to the periapical area. Lateral incisors (n = 32), 16 with curvature angles smaller or equal to 10º (GI) and 16 between 11º and 25º angles (GII) were submitted to Hero 642 rotary instrumentation with different surgical diameters: (A) 30.02 and (B) 45.02. Irrigation was performed at each change of instrument with 5 mL of ultrapure Milli-Q water and the extruded material through the apical foramen was collected. Root cross-sections were subjected to histological analysis by optical microscopy (×40) and the images were evaluated morphometrically using the Image Tool software. Quantification of the extruded material was performed by weighing after liquid evaporation. ANOVA showed no statistically significant differences (p>0.05) among the groups with respect to the procedures used to clean the apical region. Considering the amount of extruded material, the Tukey's HSD showed that canals with mild curvature prepared with the 45.02 surgical diameter showed significantly higher values (p<0.05) that those of the other groups, which were similar between themselves (p>0.05). In conclusion, the effect of cleaning the apical region did not differ in the groups, considering root curvature and the surgical diameter of instruments used for apical preparation. The amount of extruded material was greater in canals with mild curvature that were prepared with the 45.02 surgical instrument diameter.

Este estudo avaliou, in vitro, por meio de microscopia óptica e morfometria, a limpeza da região apical em canais radiculares com curvatura leve e moderada submetidos ao preparo biomecânico com sistema rotatório, bem como avaliou a quantidade de material extruído para a área apical. Incisivos laterais (n = 32), sendo 16 com ângulo de curvatura igual ou inferior a 10º (GI) e 16 entre 11º e 25º (GII), foram submetidos à instrumentação rotatória com o sistema Hero 642 com diferentes diâmetros cirúrgicos: (A) 30,02 e (B) 45,02. A irrigação, a cada troca de instrumento, foi realizada com água ultra-pura de Milli Q (5 mL), e o material extruído através do forame apical foi coletado. As raízes foram submetidas a análise histológica sob microscopia óptica (40×) e as imagens foram submetidas à análise morfométrica utilizando o software Image Tool. A quantificação do material extruído foi realizada por pesagem, após a evaporação do líquido. A análise de variância não mostrou diferença estatística significante em relação à limpeza da região apical nos diferentes grupos testados (p>0,05). Considerando a quantidade de material extruído, o teste de T6ukey mostrou que os canais com curvatura leve preparados com o diâmetro cirúrgico 45,02 apresentaram os maiores valores, sendo estatisticamente diferente dos demais grupos (p<0,05) que foram semelhantes entre si (p>0,05). Pode-se concluir que a limpeza da região apical não diferiu entre os diferentes grupos, considerando a curvatura radicular e o diâmetro cirúrgico. A quantidade de material extruído foi maior nos canais preparados com curvatura leve que foram preparados com diâmetro cirúrgico 45,02.

Relationship between the size of patency file and apical extrusion of sodium hypochlorite.

Background: Sodium hypochlorite (NaOCl) is the most widely used endodontic irrigant because of its excellent antimicrobial, organic tissue dissolving, and lubricating properties. However, it is highly cytotoxic to the periapical tissues. Aim: This study evaluated in vitro the extrusion of 5.25% NaOCl through the apical foramina of mesiobuccal (MB) root canals of maxillary first molars in two experimental conditions: Before apical debridement and after apical debridement with different instrument sizes to ensure direct access to the apical foramen (apical patency). Materials and Methods: Coronal accesses were prepared in 17 teeth and the apical foramina of the distobuccal and palatal root canals were sealed. The teeth were held in acrylic receptacles with the roots turned upwards to reproduce their position in the maxillary dental arch. The receptacles were filled with a starch/KI solution (a reagent that changes its color to blue after contacting NaOCl) covering the roots. The experiment had two phases: P1: Irrigation of the MB canals with 5.25% NaOCl without previous establishment of apical patency; P2: Canal irrigation after use of size 10 K-file and size 15 Flexofile as patency files. Only specimens with no NaOCl extrusion in P1 were assigned to P2. NaOCl was delivered pressureless at the canal entrance. The moment that the starch/KI solution contacted NaOCl was captured on digital photographs. Results and Conclusions: There was no NaOCl extrusion in nine specimens in P1, but all of these teeth had irrigant extrusion in P2. The 5.25% NaOCl used as an endodontic irrigant showed great capacity to extrude beyond both intact and small-sized apical foramina of MB root canals of maxillary first molars.

Apical extrusion of debris by manual and mechanical instrumentation

The aim of the present study was to assess the presence of apically extruded debris and evaluate the influence of canal curvature on the amount of debris produced by manual and mechanical techniques. Forty single-rooted mature teeth with 15 to 30 degree of root canal curvature were selected. The presence of only one foramen was confirmed using a magnifying lens. A size 15 K-file was placed up to the apical foramen to determine the patency. Working length was determined with the same instrument, 1 mm short of the foramen. According to the employed technique, the groups were labeled as follows: Group 1 - Manual instrumentation with Mor-flex files; Group 2 - Mechanical instrumentation with Cursor and Mor-flex files; Group 3 - Manual instrumentation with Flexi-cut files; Group 4 - Mechanical instrumentation with Cursor and Flexi-cut files. During instrumentation, the root canals were irrigated with 20 mL. Debris extruded through the apical foramen was collected using the Myers and Montgomery technique. The values (in mg) were: Group 1: 0.422 ± 0.683; Group 2: 0.688 ± 0.795; Group 3: 0.409 ± 0.323; Group 4: 0.810 ± 0.708. Data were analyzed statistically by ANOVA at 5 percent significance level. There was no statistically significant difference among the groups (p<0.05). No statistically significant differences were found between slight and moderate curvatures in terms of the amount of extruded debris (p>0.05).

O objetivo deste trabalho foi registrar a presença de material extruído apicalmente e estudar a influência da curvatura dos canais radiculares na quantidade de material, após a instrumentação manual e mecânica. Foram selecionados 40 dentes uniradiculares com ápice maduro, com curvatura do canal entre 15 e 30 graus e somente um forame apical. Verificou-se a patência do forame usando uma lima tipo-K no. 15 e se determinou a extensão de trabalho a 1 mm do forame. Considerando a técnica empregada, se formaram os seguintes grupos: Grupo 1 - instrumentação manual com limas Mor-flex; Grupo 2 - instrumentação mecânica com Cursor e limas Mor-flex; Grupo 3 - instrumentação manual com limas Flexi-cut e Grupo 4 - instrumentação mecânica com Cursor e limas Flexi-cut. Cada canal foi irrigado, enquanto era preparado, com 20 mL de água destilada. Para a coleta do material se aplicou a técnica proposta por Myers e Montgomery. Os valores, em miligramas obtidos em cada grupo foram: Grupo 1 - 0,422 ± 0,683; Grupo 2 - 0,688 ± 0,795; Grupo 3 - 0,409 ± 0,323 e Grupo 4 - 0,810 ± 0,708. A análise estatística (ANOVA) não detectou diferenças estatisticamente significantes (p> 0,05) nas quantidades médias de material extruído em cada grupo. Comparando a influência da curvatura dos canais, não se encontrou diferenças estatisticamente significantes nas quantidades médias de material extruído segundo as curvaturas foram leves ou moderadas (test t para variâncias desiguais p>0,05).

Influence of plugger penetration depth on the apical extrusion of root canal sealer in continuous wave of condensation technique / 대한치과보존학회지

The purpose of this study was to evaluate the influence of plugger penetration depth on the apical extrusion of root canal sealer during root canal obturation with Continuous Wave of Condensation Technique. Root canals of forty extracted human teeth were divided into four groups and were prepared up to size 40 of 0.06 taper with ProFile. After drying, canals of three groups were filled with Continuous Wave of Condensation Technique with System B(TM) and different plugger penetration depths of 3, 5, and 7 mm from the apex. Canals of one group were filled with cold lateral compaction technique as a control. Canals were filled with non-standardized master gutta-percha cones and 0.02 mL of Sealapex. Apical extruded sealer was collected in a container and weighed. Data was analyzed with one-way ANOVA and Duncan's Multiple Range Test. 3 and 5 mm penetration depth groups in Continuous Wave of Condensation Technique showed significantly more extrusion of root canal sealer than 7 mm penetration depth group (p < 0.05). However, there was no significant difference between 7 mm depth group in Continuous Wave of Condensation Technique and cold lateral compaction group (p < 0.05). The result of this study demonstrates that deeper plugger penetration depth causes more extrusion of root canal sealer in root canal obturation by Continuous Wave of Condensation Technique. Therefore, special caution is needed when plugger penetration is deeper in the canal in Continuous Wave of Condensation Technique to minimize the amount of sealer extrusion beyond apex.