Root canal length changes during mechanical preparation due to different cervical enlargement patterns.

This study aimed to evaluate the root canal real length (RL) changes due to the mechanical instrumentation use with different flaring magnitudes. After access cavity, 60 mesial root canals of mandibular molars were randomly separated in three groups: Hyflex EDM (HF; #25/.12, #10/.05 e #25/~), Reciproc Blue (RB; R25), and MTwo (M2; #10/.04, #15/.05, #20/.06 e #25/.06). The RL was defined as the apical limit, and 2.5% sodium hypochlorite irrigating solution was chosen. After the access cavity (RL 1), cervical flaring (RL 2), and complete chemical-mechanical preparation (RL 3), the RL was evaluated. The RL was evaluated by a blind examiner with the aid of a microscope (16x) placing the endodontic file stop at the coronary reference. When comparing length measurements, the RL was shorter before instrumentation than that after instrumentation. A reduction of 0.65 mm (HF), 0.61 mm (RB), and 0.48 mm (M2) was observed. However, among groups, no statistical differences were found (p > 0.05). Under the conditions tested, it can be inferred that all mechanical systems provoked RL variations, which emphasizes the need for constant verification of the odontometry, mainly before root canal obturation.

Evaluation of foramen locating accuracy of an endodontic motor integrated with electronic foramen employing optimal glide path kinematics.

OBJECTIVE: This study aimed to evaluate the accuracy of the auto apical function in the maintenance of the apical limit of instrumentation during glide path procedures when associated to OGP kinematics of Tri Auto ZX2, compared to the continuous rotation of the same motor, as well as Root ZX II and VDW Gold. MATERIALS AND METHODS: Forty-eight extracted human mandibular single-rooted premolars were selected. After endodontic access, cervical pre-flaring was performed using size 30, 0.10 taper rotary instruments, and the apical foramen size was standardized to 200 µm. Teeth were randomly divided into four groups (n = 12) according to the device and kinematics. For all the groups, the Auto Apical Stop function (AAS) was set to the 0.0 mark. Glide path instruments size 25, .01 taper were activated inside the canals until the apical limit was reached. Then, the files were fixed with cyanoacrylate to the teeth and decoupled from the equipment. Data were statistically analyzed in GraphPad Prism 6.0 software with the significance set at 5% (Kruskal-Wallis tests). RESULTS: There was no difference in the mean deviation between the groups. No significant difference was found among the groups when the distributions and percentages of differences between the file tip and the apical foramen were compared (P > 0.05). CONCLUSION: The use of auto apical function at the 0.0 mark of all tested devices provided an adequate control of the apical limit during glide path preparation. Foramen locating accuracy of Tri Auto ZX2 in OGP kinematics was similar to those of Tri Auto ZX2, Root ZX II, and VDW Gold in continuous kinematics. CLINICAL RELEVANCE: Clinical strategies in canal negotiation and glide path as OGP motion associated to electronic foramen locators could reduce iatrogenic risk of deviation and file fractures and create an easier initial preparation to facilitate endodontic procedures.

Root canal length changes during mechanical preparation due to different cervical enlargement patterns

Abstract This study aimed to evaluate the root canal real length (RL) changes due to the mechanical instrumentation use with different flaring magnitudes. After access cavity, 60 mesial root canals of mandibular molars were randomly separated in three groups: Hyflex EDM (HF; #25/.12, #10/.05 e #25/~), Reciproc Blue (RB; R25), and MTwo (M2; #10/.04, #15/.05, #20/.06 e #25/.06). The RL was defined as the apical limit, and 2.5% sodium hypochlorite irrigating solution was chosen. After the access cavity (RL 1), cervical flaring (RL 2), and complete chemical-mechanical preparation (RL 3), the RL was evaluated. The RL was evaluated by a blind examiner with the aid of a microscope (16x) placing the endodontic file stop at the coronary reference. When comparing length measurements, the RL was shorter before instrumentation than that after instrumentation. A reduction of 0.65 mm (HF), 0.61 mm (RB), and 0.48 mm (M2) was observed. However, among groups, no statistical differences were found (p > 0.05). Under the conditions tested, it can be inferred that all mechanical systems provoked RL variations, which emphasizes the need for constant verification of the odontometry, mainly before root canal obturation.

Influence of Different Coronal Preflaring Protocols on Electronic Foramen Locators Precision.

The aim of this study was to evaluate the influence of different coronal preflaring protocols (absent, conservative and conventional) on the accuracy of Root ZX II, Raypex 6, and RomiApex A-15 electronic foramen locators (EFLs). Twenty mandibular molars with Vertucci's type IV mesial roots were subjected to endodontic exploration and foraminal patency confirmation. Under 16x magnification, its real lengths (RL) were measured and registered (RL1). The canals were then irrigated with 2.5% sodium hypochlorite and electronically measured (EM1) employing the alginate model; all measurements were performed in triplicate by a blind operator using adjusted endodontic hand-files introduced until the apex foramen. Coronal preflaring procedures were sequentially performed with #25/.06 (conservative) and #25/.12 (conventional) instruments; new RLs extents were performed after each coronal preparation protocol (RL2/RL3), as same as electronic measurements (EM2/EM3). The devices error (mm) was evaluated considering the difference between RLs and EMs at each preparation stage; their precision was stablished adopting ±0.5 mm as tolerance margin. The EFLs error significantly reduced after conventional coronal preflaring protocol (p<0.05), which not occur after the conservative one. The best precisions values were noted after conventional preparation as 90% (Root ZX II), 97.5% (Raypex 6), and 92.5% (RomiApex A-15). No significant differences were found in EFLs comparisons, regardless of the coronal protocol tested (p>0.05). Under the conditions tested it can be concluded that the EFLs evaluated were precise. Moreover, the preflaring protocols influences its accuracy's, where the less conservative one produced the best results.

Influence of different coronal preflaring protocols on electronic foramen locators precision

Abstract: The aim of this study was to evaluate the influence of different coronal preflaring protocols (absent, conservative and conventional) on the accuracy of Root ZX II, Raypex 6, and RomiApex A-15 electronic foramen locators (EFLs). Twenty mandibular molars with Vertucci's type IV mesial roots were subjected to endodontic exploration and foraminal patency confirmation. Under 16x magnification, its real lengths (RL) were measured and registered (RL1). The canals were then irrigated with 2.5% sodium hypochlorite and electronically measured (EM1) employing the alginate model; all measurements were performed in triplicate by a blind operator using adjusted endodontic hand-files introduced until the apex foramen. Coronal preflaring procedures were sequentially performed with #25/.06 (conservative) and #25/.12 (conventional) instruments; new RLs extents were performed after each coronal preparation protocol (RL2/RL3), as same as electronic measurements (EM2/EM3). The devices error (mm) was evaluated considering the difference between RLs and EMs at each preparation stage; their precision was stablished adopting ±0.5 mm as tolerance margin. The EFLs error significantly reduced after conventional coronal preflaring protocol (p<0.05), which not occur after the conservative one. The best precisions values were noted after conventional preparation as 90% (Root ZX II), 97.5% (Raypex 6), and 92.5% (RomiApex A-15). No significant differences were found in EFLs comparisons, regardless of the coronal protocol tested (p>0.05). Under the conditions tested it can be concluded that the EFLs evaluated were precise. Moreover, the preflaring protocols influences its accuracy's, where the less conservative one produced the best results.

Resumo O objetivo deste estudo foi avaliar a influência de diferentes protocolos de pré-alargamento cervical (ausente, conservador e convencional) na precisão dos localizadores eletrônicos foraminais (LEFs) Root ZX II, Raypex 6 e RomiApex A-15. Vinte molares inferiores com raízes mesiais do tipo IV de Vertucci foram submetidos à exploração endodôntica e confirmação da patência foraminal. Sob ampliação de 16x, seus comprimentos reais (CR) foram medidos e registrados (CR1). Os canais foram então irrigados com hipoclorito de sódio a 2,5% e medidos eletronicamente (ME1) utilizando o modelo em alginato; todas as medidas foram realizadas em triplicata por um operador cego, utilizando limas endodônticas ajustadas introduzidas até o forame apical. Os procedimentos de pré-alargamento cervical foram realizados sequencialmente com os instrumentos #25/.06 (conservador) e #25/.12 (convencional); novas determinações de CRs foram realizadas após cada protocolo de preparação cervical (CR2/CR3), da mesma forma que as medidas eletrônicas (ME2/ME3). O erro dos dispositivos (mm) foi avaliado considerando a diferença entre CRs e MEs em cada estágio de preparação; sua precisão foi estabelecida adotando ± 0,5 mm como margem de tolerância. O erro dos LEFs reduziu significativamente após o protocolo convencional de alargamento cervical (p<0,05), o que não ocorreu após o conservador. Os melhores valores de precisão foram observados após a preparação convencional como 90% (Root ZX II), 97,5% (Raypex 6) e 92,5% (RomiApex A-15). Não foram encontradas diferenças significantes nas comparações entre os LEFs, independentemente do protocolo cervical testado (p>0,05). Sob as condições testadas, pode-se concluir que os LEFs avaliados foram precisos. Além disso, os protocolos de alargamento influenciam sua precisão, onde o menos conservador produziu os melhores resultados.

Odontometria eletrônica em Endodontia: quando e como fazer o melhor uso dos localizadores eletrônicos foraminais / Electronic foramen locators: when and how to use them

Novas tecnologias vêm sendo incorporadas aos protocolos endodônticos com o intuito de facilitar ou tornar mais eficiente a atuação dos profissionais que os executam. Nessa perspectiva, os localizadores eletrônicos foraminais (LEFs) apresentam-se como ferramentas quase indispensáveis para uma correta determinação do comprimento real dos condutos. Por sua vez, essa etapa reveste-se de vital importância para que os procedimentos endodônticos sejam mais precisos e limitem-se às extensões desejadas pelo endodontista, sem delegá-las ao acaso ou a variações anatômicas na relação entre os forames apicais (FA) e os vértices radio- gráficos. Objetivo: O objetivo do presente artigo é discorrer sobre os protocolos de emprego dos LEFs e a influência que algumas condições clínicas podem exercer na precisão desses dispositivos. Resultados: Tomando por base a evidência científica disponível, aspectos como o ajuste do instrumento e a relação desse com o preparo cervical, o limite apical de penetração e a sequência de emprego do LEF, assim como a condição foraminal, parecem interferir significativamente nos valores de precisão observados. Conclusões: Torna-se evidente que o conhecimento do funcionamento dos localizadores e sua relação com as diversas situações clínicas per- mite utilizá-los de maneira mais efetiva, incrementando sua precisão e extraindo do equipamento, qualquer que seja, um melhor resultado, favorecendo a correta obtenção do comprimento do canal radicular, assim colaborando para a realização de uma Endodontia mais previsível e de qualidade (AU).

Novas tecnologias vêm sendo incorporadas aos protocolos endodônticos com o intuito de facilitar ou tornar mais eficiente a atuação dos profissionais que os executam. Nessa perspectiva, os localizadores eletrônicos fora- minais (LEFs) apresentam-se como ferramentas quase indis- pensáveis para uma correta determinação do comprimento real dos condutos. Por sua vez, essa etapa reveste-se de vital importância para que os procedimentos endodônticos sejam mais precisos e limitem-se às extensões desejadas pelo endodontista, sem delegá-las ao acaso ou a variações anatômicas na relação entre os forames apicais (FA) e os vértices radio- gráficos. Objetivo: O objetivo do presente artigo é discorrer sobre os protocolos de emprego dos LEFs e a influência que algumas condições clínicas podem exercer na precisão desses dispositivos. Resultados: Tomando por base a evidência científica disponível, aspectos como o ajuste do instrumento e a relação desse com o preparo cervical, o limite apical de penetração e a sequência de emprego do LEF, assim como a condição foraminal, parecem interferir significativamente nos valores de precisão observados. Conclusões: Torna-se evidente que o conhecimento do funcionamento dos localizadores e sua relação com as diversas situações clínicas per- mite utilizá-los de maneira mais efetiva, incrementando sua precisão e extraindo do equipamento, qualquer que seja, um melhor resultado, favorecendo a correta obtenção do comprimento do canal radicular, assim colaborando para a realização de uma Endodontia mais previsível e de qualidade(AU).

Debris extrusion and foraminal deformation produced by reciprocating instruments made of thermally treated NiTi wires.

To evaluate the amount of apically extruded debris, percentage of foraminal enlargement and apical foramen (AF) deformation that occurred during root canal preparation with different reciprocation systems: Reciproc, WaveOne (M-Wire), and ProDesign R (Shape Memory Technology Wire) at two different working lengths (WLs): 0.0 and 1.0 mm beyond the AF. The AF of 120 root canals in 60 mesial roots of mandibular molars were photographed with stereomicroscope and randomly assigned into four groups: manual, Reciproc (REC), WaveOne (WO), and ProDesign R (PDR); subsequently, they were further subdivided according to the WL (n=15). Teeth were instrumented, coupled to a dual collecting chamber, and then another photograph of each AF was captured. Extrusion was analysed by determining the weight of extruded debris. Each AF diameter was measured in pre- and post-instrumentation images to determine deformation, which was analysed, and afterwards the final format of AFs was classified (circular/oval/deformed). We found no significant differences when analysing each system at different WLs. When considering each WL, REC and WO showed highest extrusion values (P<.05); for AF enlargement, differences were observed only for WO, when it was used beyond the AF; differences were observed among M-Wire groups beyond the AF (P<.05). AF deformation was observed in all groups; PDR showed the lowest AF deformation values at both WLs; M-Wire groups showed 50% strain beyond the AF. Authors concluded that beyond the apical limit, the alloy and taper are important aspects when considering extrusion and deformation.

Debris extrusion and foraminal deformation produced by reciprocating instruments made of thermally treated NiTi wires

Abstract Objective To evaluate the amount of apically extruded debris, percentage of foraminal enlargement and apical foramen (AF) deformation that occurred during root canal preparation with different reciprocation systems: Reciproc, WaveOne (M-Wire), and ProDesign R (Shape Memory Technology Wire) at two different working lengths (WLs): 0.0 and 1.0 mm beyond the AF. Material and methods The AF of 120 root canals in 60 mesial roots of mandibular molars were photographed with stereomicroscope and randomly assigned into four groups: manual, Reciproc (REC), WaveOne (WO), and ProDesign R (PDR); subsequently, they were further subdivided according to the WL (n=15). Teeth were instrumented, coupled to a dual collecting chamber, and then another photograph of each AF was captured. Extrusion was analysed by determining the weight of extruded debris. Each AF diameter was measured in pre- and post-instrumentation images to determine deformation, which was analysed, and afterwards the final format of AFs was classified (circular/oval/deformed). Results We found no significant differences when analysing each system at different WLs. When considering each WL, REC and WO showed highest extrusion values (P<.05); for AF enlargement, differences were observed only for WO, when it was used beyond the AF; differences were observed among M-Wire groups beyond the AF (P<.05). AF deformation was observed in all groups; PDR showed the lowest AF deformation values at both WLs; M-Wire groups showed 50% strain beyond the AF. Conclusion Authors concluded that beyond the apical limit, the alloy and taper are important aspects when considering extrusion and deformation.

Determination of the Accuracy of 5 Electronic Apex Locators in the Function of Different Employment Protocols.

INTRODUCTION: The aim of this study was to evaluate the accuracy of 5 electronic apex locators (EALs): Root ZX II (RZX; J Morita, Tokyo, Japan), Raypex 6 (RAY; VDW GmbH, Munich, Germany), Apex ID (AID; SybronEndo, Orange, CA), Propex II (PRO; Dentsply Maillefer, Ballaigues, Switzerland), and Propex Pixi (PIXI, Dentsply Maillefer) when used in the following protocols: (1) -1.0, insertion up to 1.0 mm below the apical foramen (AF); (2) 0.0/-1.0, insertion until the AF and withdrawn 1.0 mm short of the AF; (3) 0.0, insertion until the AF; and (4) over/0.0, insertion until "over" and withdrawal to AF. METHODS: Thirty human lower premolars had coronary accesses and cervical and middle thirds preparations performed, allowing AF standardization (200 µm). Using an alginate experimental model, root canal length (RCL) measurements were performed sequentially with EALs following each of the protocols. RESULTS: Considering the suggested protocols, the lowest mean error values were observed in 0.0, 0.10 mm (RZX), 0.13 mm (RAY), 0.16 mm (AID), 0.23 mm (PRO), and 0.10 mm (PIXI), without a significant difference for over/0.0 (P > .05). Comparing the results obtained in 0.0 with those found in -1.0 and 0.0/-1.0, significant differences were observed for most EALs (P < .05). For the comparison between EALs, significant differences were observed only in protocols -1.0 and over/0.0 (P < .05). CONCLUSIONS: Under the conditions of the study, it was concluded that, regardless of the mechanism of the device, the best results were found when electronic RCL measurement was performed at the AF; furthermore, the electronic withdrawal did not offer any additional advantage over the reach of the AF.

Influence of NiTi alloy on the root canal shaping capabilities of the ProTaper Universal and ProTaper Gold rotary instrument systems.

OBJECTIVE: This study aimed to evaluate the influence of the NiTi wire in Conventional NiTi (ProTaper Universal PTU) and Controlled Memory NiTi (ProTaper Gold PTG) instrument systems on the quality of root canal preparation. MATERIAL AND METHODS: Twelve mandibular molars with separate mesial canals were scanned using a high-definition microcomputed tomography system. The PTU and PTG instruments were used to shape twelve mesial canals each. The canals were scanned after preparation with F2 and F3 instruments of the PTU and PTG systems. The analyzed parameters included the remaining dentin thickness at the apical and cervical levels, root canal volume and untouched canal walls. Data was analyzed for statistical significance by the Friedman and Dunn's tests. For the comparison of data between groups, the Mann-Whitney test was used. RESULTS: In the pre-operative analysis, there were no statistically significant differences between the groups in terms of the area and volume of root canals (P>.05). There was also no statistically significant difference between the systems with respect to root canal volume after use of the F2 and F3 instruments. There was no statistical difference in the dentin thickness at the first apical level between, before and after instrumentation for both systems. At the 3 cervical levels, the PTG maintained centralization of the preparation on the transition between the F2 and F3 instruments, which did not occur with the PTU. Conclusion The Conventional NiTi (PTU) and Controlled Memory NiTi (PTG) instruments displayed comparable capabilities for shaping the straight mesial root canals of mandibular molars, although the PTG was better than the PTU at maintaining the centralization of the shape in the cervical portion.

Influence of NiTi alloy on the root canal shaping capabilities of the ProTaper Universal and ProTaper Gold rotary instrument systems

Abstract Objective This study aimed to evaluate the influence of the NiTi wire in Conventional NiTi (ProTaper Universal PTU) and Controlled Memory NiTi (ProTaper Gold PTG) instrument systems on the quality of root canal preparation. Material and Methods Twelve mandibular molars with separate mesial canals were scanned using a high-definition microcomputed tomography system. The PTU and PTG instruments were used to shape twelve mesial canals each. The canals were scanned after preparation with F2 and F3 instruments of the PTU and PTG systems. The analyzed parameters included the remaining dentin thickness at the apical and cervical levels, root canal volume and untouched canal walls. Data was analyzed for statistical significance by the Friedman and Dunn’s tests. For the comparison of data between groups, the Mann-Whitney test was used. Results In the pre-operative analysis, there were no statistically significant differences between the groups in terms of the area and volume of root canals (P>.05). There was also no statistically significant difference between the systems with respect to root canal volume after use of the F2 and F3 instruments. There was no statistical difference in the dentin thickness at the first apical level between, before and after instrumentation for both systems. At the 3 cervical levels, the PTG maintained centralization of the preparation on the transition between the F2 and F3 instruments, which did not occur with the PTU. Conclusion The Conventional NiTi (PTU) and Controlled Memory NiTi (PTG) instruments displayed comparable capabilities for shaping the straight mesial root canals of mandibular molars, although the PTG was better than the PTU at maintaining the centralization of the shape in the cervical portion.

Comparative Effectiveness of New Mechanical Irrigant Agitating Devices for Debris Removal from the Canal and Isthmus of Mesial Roots of Mandibular Molars.

INTRODUCTION: The aim of this study was to compare the effectiveness of Easy Clean (Easy Dental Equipment, Belo Horizonte, MG, Brazil) in continuous and reciprocating motion, passive ultrasonic irrigation (PUI), Endoactivator systems (Dentsply Maillefer, Ballaigues, Switzerland), and conventional irrigation for debris removal from root canals and isthmus. METHODS: Fifty mesial roots of mandibular molars were embedded in epoxy resin using a metal muffle; afterward, the blocks containing the roots were sectioned at 2, 4, and 6 mm from the apex. After instrumentation, the roots were divided into 5 groups (n = 10) for application of the final irrigation protocol using Easy Clean in continuous rotation, Easy Clean in reciprocating motion, PUI, Endoactivator, and conventional irrigation. Scanning electron microscopic images were taken after instrumentation and after the first, second, and third activation of irrigating solution to evaluate the area of remaining debris with image J software (National Institutes of Health, Bethesda, MD). RESULTS: The protocol of 3 irrigating solution activations for 20 seconds provided better cleaning of the canal and isthmus. On conclusion of all procedures, analysis of the canals showed a statistical difference only at 2 mm; the Easy Clean in continuous rotation was more efficient than conventional irrigation (P < .05). On conclusion of all steps, the largest difference was observed in the isthmus in which the Easy Clean in continuous rotation was more effective than conventional irrigation at the 3 levels analyzed and the Endoactivator at 4 mm (P < .05). The PUI promoted greater cleaning than conventional irrigation at 6 mm (P < .05). There was no statistical difference between Easy Clean in continuous rotation, Easy Clean in reciprocating motion, and PUI (P > .05). CONCLUSIONS: Irrigating solution activation methods provided better cleaning of the canal and isthmus, especially the Easy Clean used in continuous rotation. The protocol of 3 irrigating solution activations for 20 seconds favored better cleaning.

Changes in Root Canal Length Determined during Mechanical Preparation Stages and Their Relationship with the Accuracy of Root ZX II.

INTRODUCTION: The aim of this study was to determine the variations in root canal length (RCL) occurring during endodontic treatment stages (initial, preflared, and concluded) and correlate them with the accuracy of Root ZX II (RZX). METHODS: After coronal access, 26 mandibular molars had the apical foramen of the 52 mesial canals standardized (250 µm) and their respective initial RCL was recorded (RCL1 = initial) by using a clinical microscope (×16) and manual K-file instruments. By using the alginate model, sequential electronic measurements were taken with the RZX. After the initial measurement (EM1), WaveOne Primary instruments were used to prepare the cervical and middle thirds of the root canals, and then the second RCL and EM measurements (RCL2/EM2 = preflared) were obtained. Finally, mechanical preparation was concluded, and the measurement procedures were repeated to obtain the final RCL and EM measurements (RCL3/EM3 = concluded). RESULTS: Statistically significant differences were observed in all comparisons in the RCL (P < .05). The RCL1 - RCL3 showed the highest variation (0.6 mm), with the extent of specimens reduced by up to 1.75 mm. No statistically significant differences were found in the accuracy of the RZX (P > .05); 100% precision (± 0.5 mm) was found in all stages. CONCLUSIONS: Under the conditions of this study, the authors concluded that during endodontic treatment, the extent of the RCL was reduced, thereby jeopardizing control of the apical limit during instrumentation and/or obturation. The RZX was extremely accurate in all evaluated stages.

Effect of ultrasonic tip and root-end filling material on bond strength.

OBJECTIVES: The objective of this study was to evaluate the bond strength of three root-end filling materials (MTAA-MTA Angelus, MTAS-experimental MTA Sealer, and ZOE- zinc oxide and eugenol cement) in retrograde preparations performed with different ultrasonic tips (CVD, Trinity, and Satelec). MATERIALS AND METHOD: Ninety 2-mm root sections from single-rooted human teeth were used. The retrograde cavities were prepared by using the ultrasonic tips, coupled to a device for position standardization. The specimens were randomly divided into nine groups: CVD MTAA; CVD MTAS; CVD ZOE; Trinity MTAA; Trinity MTAS; Trinity ZOE; Satelec MTAA; Satelec MTAS; Satelec ZOE. Each resin disc/dentin/root-end filling material was placed in the machine to perform the push-out test. The specimens were examined in a stereomicroscope to evaluate the type of failure. Data were submitted to statistical analysis using ANOVA and Tukey tests (α = 0.05). RESULTS: The highest bond strength was observed for the CVD tip irrespective of the material used (P < 0.05). There was no significant difference for the Trinity TU-18 diamond and S12 Satelec tips (P > 0.05). MTAA and MTAS showed highest bond strength. The most common type of failure was adhesion between the filling material and dentin wall, except for ZOE, where mixed failure was predominant. CONCLUSIONS: The CVD tip favored higher bond strength of the root-end filling materials. MTA Angelus and experimental MTAS presented bond strength to dentin prepared with ultrasonic tips. CLINICAL RELEVANCE: Root-end preparation with the CVD tip positively influences the bond strength of root-end filling materials. MTA Angelus and experimental MTAS present bond strength to be used as root-end filling materials.

Efficacy of Electronic Foramen Locators in Controlling Root Canal Working Length during Rotary Instrumentation.

The present study evaluated the efficacy of electronic foramen locators (EFLs) to control root canal working length during rotary instrumentation and to assess possible reliability variations of different working lengths. Forty-eight human mandibular bicuspids were randomly divided in 2 groups according to the used device, Root ZX II (RZX) and Propex II (PRO). They were further subdivided in 2 subgroups according to the root canal preparation level (0.0 and -1.0). Preparation was performed with the Protaper rotary system using a crown-down technique. RZX was employed on its automatic auto-reverse mode (AAR) and PRO was used with the MPAS-10R contra-angle to monitor the preparation. The last used file (F3) was fixed, and the apical portion of the teeth was worn buccolingually, allowing to measure the extent between the file tip and the apical foramen (AF). The precision values of 0.0 mm and -1.0 mm were 100% and 0.0% for RZX, and 100% and 66.7% for PRO, respectively, with a range of ±0.5 mm. Statistical analysis showed no differences between the groups at 0.0 mm. However, at -1.0 mm, RZX showed the poorest results (0.96±0.11 mm), followed by PRO (0.43±0.23 mm). The difference between RZX and PRO was statistically significant. The EFLs were precise in maintaining the working length during rotary preparation when reaching the AF, but when their penetration was limited, both devices showed decreased precision; the RZX AAR failed in all instances.

Efficacy of Electronic Foramen Locators in Controlling Root Canal Working Length during Rotary Instrumentation

Abstract: The present study evaluated the efficacy of electronic foramen locators (EFLs) to control root canal working length during rotary instrumentation and to assess possible reliability variations of different working lengths. Forty-eight human mandibular bicuspids were randomly divided in 2 groups according to the used device, Root ZX II (RZX) and Propex II (PRO). They were further subdivided in 2 subgroups according to the root canal preparation level (0.0 and -1.0). Preparation was performed with the Protaper rotary system using a crown-down technique. RZX was employed on its automatic auto-reverse mode (AAR) and PRO was used with the MPAS-10R contra-angle to monitor the preparation. The last used file (F3) was fixed, and the apical portion of the teeth was worn buccolingually, allowing to measure the extent between the file tip and the apical foramen (AF). The precision values of 0.0 mm and -1.0 mm were 100% and 0.0% for RZX, and 100% and 66.7% for PRO, respectively, with a range of ±0.5 mm. Statistical analysis showed no differences between the groups at 0.0 mm. However, at -1.0 mm, RZX showed the poorest results (0.96±0.11 mm), followed by PRO (0.43±0.23 mm). The difference between RZX and PRO was statistically significant. The EFLs were precise in maintaining the working length during rotary preparation when reaching the AF, but when their penetration was limited, both devices showed decreased precision; the RZX AAR failed in all instances.

Resumo: O presente estudo avaliou a eficiência de localizadores eletrônicos foraminais (LEFs) em controlar o limite apical de instrumentação durante o preparo com instrumentos rotatórios. Adicionalmente, determinou-se possíveis variações quando do emprego de diferentes comprimentos de trabalho. Quarenta e oito pré-molares inferiores humanos foram randomicamente divididos em 2 grupos de acordo com o aparelho empregado, Root ZX II (RZX) e Propex II (PRO). Em seguida foram subdivididos em 2 subgrupos em função do limite de preparo (0,0 e -1,0 mm). O preparo dos canais foi realizado com o sistema Protaper em sentido coroa-ápice. O RZX foi utilizando em sua função auto-reverso automático (ARA) e o PRO associado ao contra-angulo MPAS-10R, foi empregado como ferramenta de monitoramento durante o preparo. O último instrumento utilizado (F3) foi fixado em posição, após o que a porção apical dos dentes foi desgastada permitindo a determinação da distância entre a ponta dos instrumentos e o forame apical (FA). A precisão a 0,0 mm e -1,0 mm foi de 100% e 0,0% para o RZX, e de 100% e 66,7% para o PRO, respectivamente, considerando uma margem de ±0,05 mm. A análise estatística não encontrou diferenças entre os grupos a 0,0 mm, todavia, a -1,0 mm, o RZX ofereceu os piores resultados (0,96±0,11 mm), seguido do PRO (0,43±0,23 mm). Esta diferença foi estatisticamente significante. Os LEFs foram precisos na manutenção do comprimento de trabalho durante o preparo rotatório quando se atingiu o FA, todavia, quando esta penetração foi limitada, ambos os aparelhos perderam em precisão; o sistema ARA do RZX falhou em todos os casos.

Ex Vivo Evaluation of the Accuracy of Electronic Foramen Locators in Root Canals with an Obstructed Apical Foramen.

INTRODUCTION: The objective of the present study was to evaluate the accuracy of electronic foramen locators (EFLs), Root ZX II (RZX; J. Morita, Tokyo, Japan), Propex II (Dentsply Maillefer, Ballaigues, Switzerland), and Apex ID (AID; SybronEndo, Glendora, CA), in root canals with an obstructed apical foramen (OAF) and to compare them with those 1.0 mm short of the apical foramen (AF; -1.0) and at the AF (0.0). METHODS: Thirty human mandibular molars had their coronal and cervical preparations accessed. Then, the AFs were standardized (250 µm). Electronic root canal measurements were performed for the -1.0 and 0.0 working lengths, and the canals were obstructed with dentinal debris. The distance to the AF displayed by the EFLs was then recorded. The last instrument used was fixed with a cyanoacrylate-based adhesive; the apical portions of the roots were scraped, allowing for the determination of the distance between the tips of the instruments and the AFs. RESULTS: The precision rates at 0.0, -1.0, and the OAF were 94.7%, 43.9%, and 1.8% (RZX); 93.0%, 54.4%, and 54.4% (Propex II); and 93.0%, 68.5%, and 75.4% (AID), respectively (±0.5 mm). No significant differences were found between the devices at 0.0; however, for the measurements at -1.0 and the OAF, the AID offered significantly better results than RZX (P < .05). CONCLUSIONS: The absence of foraminal patency caused by dentin debris obstruction affects the accuracy of the EFLs differently, suggesting distinctive interactions with their operating mechanisms.

Scanning electronic microscopy analysis of the apical surface after of root-end resection with different methods.

To compare the time dispensed and the surface characteristics when a root-end resection was performed with a surgical ultrasonic device (VarioSurg, NSK, Japan) or with a Zekrya bur. Forty distal roots of freshly extracted mandibular molars were selected and divided into four different groups: (G1) stainless steel insert with ultrasound; (G2) diamond insert with ultrasound; (G3) stainless steel and diamond inserts with ultrasound, and (G4) Zekrya burs. The time required for the root-end resection was timed and the surface characteristics were evaluated via scanning electronic microscopy. The median times for the root-end resections were: 115.9 s for G1, 249.8 s for G2, 112.7 s for G3, and 7.44 s for G4, the latter presented a smoother root-end surface. There was no statistically significant difference in the comparisons between G3 group and G4 group (Zekrya burs). The other groups where the root-end resections were with ultrasonic devices proportioned a prolonged time to resection with irregular surfaces.

Evaluation of the maintenance of the apical limit during instrumentation with hybrid equipment in rotary and reciprocating modes.

INTRODUCTION: The objective of the present study was to evaluate ex vivo the maintenance of the apical limit during instrumentation with the Root ZX (J Morita, Tokyo, Japan) and VDW Gold (VDW GbmH, Munich, Germany) hybrid devices in rotary and reciprocating modes and determine the possible function variations of different preparation levels (0.0 mm and -1.0 mm). METHODS: Seventy-two human uniradicular mandibular premolars, which had their coronal access performed and their apical foramen (AF) standardized (200 µm) were used. After their randomized division, the root canals were chemically mechanically prepared with #F4 ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) and #R40 Reciproc (VDW GbmH) instruments. At the end of the instrumentation, the last instrument was fixed, and 4.0 mm of the apical portion was worn, permitting the measurement of the distance between the instrument tips and the AF. RESULTS: The determined precision values of 0.0 and -1.0 mm were 100% and 33.4% (Root), 100% and 41.6% (VDW Gold with rotary movement) and 100% and 33.3% (VDW Gold with reciprocating movement), respectively, with a margin of ±0.5 mm. No statistical differences were found with respect to the comparisons of every level of preparation. However, significant differences were found when comparing the groups with rotary function at the different levels, with a higher precision for the groups that reached the AF. CONCLUSIONS: It was concluded that both devices, independent of the function used, were more efficient in the maintenance of the apical limit when used until the AF; however, such reliability was compromised when -1.0 mm from the apical limit was established.

Ciência e tecnologia na Endodontia: como conciliá-las de forma adequada / Science and technology in Endodontics: how to properly assess their use

Novos recursos tecnológicos foram introduzidos na Odontologia e, em especial, na Endodontia, com o objetivo de torná-la mais previsível e de alcance a maior número de profissionais. A radiografia digital, tomografia, instrumentos oscilatórios e reciprocantes, ativação da solução irrigadora por meio do ultrassom, técnicas termoplastificadoras de obturação dos canais e o uso do MTA e do microscópio cirúrgico permitem que, casos considerados difíceis, tornem-se mais viáveis de tratamento. Todavia, é importante que o profissional, além do domínio da tecnologia, tenha embasamento científico adequado para utilizar esses recursos. Neste artigo‚ feita uma análise das diferentes tecnologias introduzidas na Endodontia

New technologies have been developed in Dentistry especially in Endodontics so that it could be a more predictable treatment as well as accessible to a large number of professionals. Technologies such as digital radiography, CT, rotary and reciprocating files, passive and constant ultrasonic irrigation, thermo-plasticized root canal filling materials, and MTA and surgical microscopes, have become viable for daily use in endodontic treatment and are an important aid in cases that were previously considered as complicated. However, it is important that the professional have proper scientific basis and knowledge of such technologies. The present paper presets an analysis of some of the technologies recently introduced in endodontics