Evaluation of the Ability of 3 Reciprocating Instruments to Remove Obturation Material: A Micro-Computed Tomography Study.

INTRODUCTION: The purpose of this study was to evaluate the ability of the Reciproc, Reciproc Blue, and WaveOne Gold systems to remove filling material during endodontic retreatment of extracted human mandibular premolars. METHODS: Thirty-nine teeth were instrumented with the Protaper Universal System to the F3 file and filled with the Tagger hybrid technique using an F3 gutta-percha cone and AH Plus cement. At the end of this period, the teeth were scanned with micro-computed tomography before and after removal of the filling material from the root canals. The teeth were divided into 3 groups (n = 13) based on the apical volume, depending on the systems used to remove the filling material. Group GR: Reciproc 40/.06; Group GRB: Reciproc Blue 40/.06; and Group GWG: WaveOne Gold 35/.06. The results were statistically analyzed using the tests of Kruskal-Wallis, Duncan, and analysis of variance at a significance level of 5%. RESULTS: The results showed that there were no significant differences between the amounts of filling material removed, either for the apical and middle regions alone or in the overall evaluation for the 3 groups (P = .97). The time evaluation statistically showed that the GR and GWG groups required less time to clean the root canals than the GRB group. CONCLUSIONS: Reciproc R40 files and WaveOne Gold Medium files required less time for endodontic treatment than Reciproc Blue R40 files. There was no difference in the ability to remove obturation material between the 3 instruments. No instrument was able to completely remove the filling material from the root canals.

Effectiveness of endodontic retreatment using WaveOne Primary files in reciprocating and rotary motions.

Objectives: This study evaluated the efficiency of WaveOne Primary files (Dentsply Sirona) for removing root canal fillings with 2 types of movement: reciprocating (RCP) and continuous counterclockwise rotation (CCR). Materials and Methods: Twenty mandibular incisors were prepared with a RCP instrument (25.08) and filled using the Tagger hybrid obturation technique. The teeth were retreated with a WaveOne Primary file and randomly allocated to 2 experimental retreatment groups (n = 10) according to movement type: RCP and CCR. The root canals were emptied of filling material in the first 3 steps of insertion, until reaching the working length. The timing of retreatment and procedure errors were recorded for all samples. The specimens were scanned before and after the retreatment procedure with micro-computed tomography to calculate the percentage and volume (mm3) of the residual filling material. The results were statistically evaluated using paired and independent t-tests, with a significance level set at 5%. Results: No significant difference was found in the timing of filling removal between the groups, with a mean of 322 seconds (RCP) and 327 seconds (CCR) (p < 0.05). There were 6 instrument fractures: 1 in a RCP motion file and 5 in continuous rotation files. The volumes of residual filling material were similar (9.94% for RCP and 15.94% for CCR; p > 0.05). Conclusions: The WaveOne Primary files used in retreatment performed similarly in both RCP and CCR movements. Neither movement type completely removed the obturation material, but the RCP movement provided greater safety.

A comparison of the physicochemical properties of AH Plus Jet with samples taken from the beginning, middle and final portions of the automix syringe system

Aim To evaluate physicochemical properties and semi-quantitative elemental analysis of AH Plus Jet with samples from the beginning, middle and final portions of the automix syringe system. Methodology Three experimental groups based on the source of the material used (beginning, middle and final portion) were established for each of the evaluated properties. Setting time, flow and radiopacity were evaluate following ANSI/ADA n. 57 specification. Set specimens was used in the semi-quantitative elemental analysis in an energy-dispersive X ray spectroscopy and scanning-electron microscopy (EDS/SEM). Statistical analysis was performed using one-way ANOVA followed by Tukey test (P<0.05). Results Flow, setting time, solubility and EDS/SEM tests showed no significant differences among the three portions of the automix syringe (P>0.05). Radiopacity test showed significant differences in the beginning of the syringe comparing to the middle and final portions (P<0.05). EDS/SEM analysis identified the presence of C, O, Al, Ca, Zr and W. The element Al, however, was found only in the final portion of the syringe. Conclusions The results of AH Plus Jet suggested an adequate ratio of the components, without segregation between organic and inorganic components, since the results of setting time, flow, solubility and EDS/SEM analysis presented similar values regardless of the portion of the syringe from where the sealer was taken.

Penetrability of AH Plus Sealer into Dentinal Tubes after Retreatment Procedure with Rotary or Reciprocating Systems and Two Additional Cleaning Methods.

Introduction: The aim of this study was to evaluate the AH Plus sealer penetration into dentinal tubules after root canal retreatment followed by two additional cleaning methods. Methods and Materials: Thirty-two mandibular premolars with single canal were prepared up to the F4 ProTaper Universal instrument and filled by a single cone technique with the addition of Rhodamine B dye to Endofill sealer. For the retreatment procedure, the teeth were randomly divided into four experimental groups (n=8) as follows: Reciproc R40 with ultrasonic activation (RU), Reciproc R40 with sonic agitation (RS), ProTaper Next until X4 instrument with ultrasonic activation (PTNU), and ProTaper Next (X4) with sonic activation (PTNS). A new root canal filling was done using a System B technique, and the AH Plus sealer was mixed with Fluorescein dye. The roots were axial sectioned at 3, 5, and 7 mm from the apex and were assessed by a confocal laser scanning microscopy using the method of epifluorescence with wavelengths of absorption and emission for rhodamine B and fluorescein. In the obtained images, the sealer penetration into the dentinal tubules was evaluated. The data were converted into percentages and submitted to Mann-Whitney and Kruskal-Wallis followed by Dunn's tests (P<0.05). Results: In all groups were found penetration of the AH Plus into the dentinal tubules. Statistical difference was found (P<0.05) in the ProTaper Next groups in relation the Reciproc groups for 3 mm root canal level regardless of additional cleaning method used. For the other sections the sealer penetration was similar (P>0.05) for all groups. Conclusion: Based on this ex vivo study the retreatment with ProTaper Next showed significantly greater penetration of AH Plus sealer into dentinal tubules in the apical third. The additional cleaning methods did not improve the removal of filling material in all sections evaluated.

Biological response to lyophilized demineralized dentin matrix implanted in the subcutaneous tissues of rats.

AIM: Lyophilized demineralized dentin matrix (LDDM) consists of a type 1 collagen complex matrix containing growth factors and no mineral crystals. Although the efficacy of LDDM for bone grafting is well known, there is limited evidence on the biological response to human lyophilized DDM. Therefore, the aim of this study was to evaluate the biological response of subcutaneous tissues in rats to powdered LDDM, mineral trioxide aggregate (MTA), and Biodentine implanted using polyethylene tubes. METHODS: Forty Wistar rats were divided into four groups (n = 10 each) depending on the experimental time intervals and were placed in polyethylene tubes containing LDDM, MTA, biodentine, and one empty control. After 3, 7, 15, and 30 observation days, the animals were sacrificed and quantitative and qualitative analysis of the subcutaneous tissue samples was carried out. The intensity of the inflammatory response was scored from 0 (no response) to 3 (severe response), and the data were statistically analyzed using ANOVA and Bonferroni tests (p < 0.05). RESULTS: All groups exhibited moderate inflammation after 3 and 7 days of observation, with presence of inflammatory infiltrate predominantly consisting of macrophages and angioblastic proliferation being observed. After 15 observation days, the control group exhibited mild inflammation and a predominance of fibroblasts, and this differed significantly from the remaining cement groups that exhibited moderate inflammation. After 30 days of observation, all groups exhibited a mild inflammatory response, predominance of fibroblasts, and a greater amount of collagen fibers. CONCLUSION: Within the limitations of this study, it can be concluded that LDDM exhibited an acceptable biological response similar to MTA and Biodentine in the subcutaneous tissues of rats.

Cryopreservation of mesenchymal stem cells derived from dental pulp: a systematic review.

OBJECTIVES: The aim of the present systematic review was to investigate the cryopreservation process of dental pulp mesenchymal stromal cells and whether cryopreservation is effective in promoting cell viability and recovery. MATERIALS AND METHODS: This systematic review was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and the research question was determined using the population, exposure, comparison, and outcomes strategy. Electronic searches were conducted in the PubMed, Cochrane Library, Science Direct, LILACS, and SciELO databases and in the gray literature (dissertations and thesis databases and Google Scholar) for relevant articles published up to March 2019. Clinical trial studies performed with dental pulp of human permanent or primary teeth, containing concrete information regarding the cryopreservation stages, and with cryopreservation performed for a period of at least 1 week were included in this study. RESULTS: The search strategy resulted in the retrieval of 185 publications. After the application of the eligibility criteria, 21 articles were selected for a qualitative analysis. CONCLUSIONS: The cryopreservation process must be carried out in 6 stages: tooth disinfection, pulp extraction, cell isolation, cell proliferation, cryopreservation, and thawing. In addition, it can be inferred that the use of dimethyl sulfoxide, programmable freezing, and storage in liquid nitrogen are associated with a high rate of cell viability after thawing and a high rate of cell proliferation in both primary and permanent teeth.

Influência da ativação ultrassônica e veículo no pH dentinário em dentes com reabsorção radicular externa simulada reparados com MTA / Influence of ultrasonic activation and mixing vehicle on dentinal pH in simulated external root resorptions repaired with MTA

Avaliar o efeito da ativação ultrassônica e do veículo do MTA no pH dentinário em dentes com reabsorção radicular externa simulada. Métodos: Uma cavidade foi preparada na superfície radicular de 46 dentes bovinos, as quais foram seladas com MTA preparado com 100% de água destilada (DW) ou com 80% DW e 20% de propilenoglicol (PG). Os dentes foram divididos em quatro grupos (n = 10), de acordo com o veículo e o protocolo de ativação ultrassônica utilizado durante a inserção do material (ativação ou sem ativação). O grupo controle (n = 6) foi deixado sem selamento. O pH foi mensurado após 15, 30 e 60 dias de imersão. Resultados: A ativação com ultrassom não alterou significativamente o pH (p>0,05). Os cimentos manipulados utilizando DW + PG apresentaram maior pH aos 15 dias, em relação ao MTA manipulado com DW (p<0,05). Conclusão: A associação de 80% de água destilada com 20% de propilenoglicol aumentou o pH dentinário, o que é positivo para o reparo de reabsorções radiculares (AU).

The aim of this study was to evaluate the effect of ultrasonic activation and MTA vehicle on dentinal pH in simulated external root resorptions. So, a cavity was prepared in the root of forty-six bovine teeth. They were filled with MTA mixed with 100% distilled water (DW) or MTA mixed with 80% DW and 20% propylene glycol (PG). Teeth were divided into four groups (n = 10), according to the vehicle (DW or PG) and ultrasonic protocol used for material insertion (activated or not). Control group (n = 6) was unfilled. The pH was assessed after 15, 30 and 60 days of immersion. As results of all that, activation with ultrasound did not significantly alter the pH (p > 0.05). The cements were mixed with either DW or DW + PG, with the later association presenting higher pH at 15 days of assessment than the former (p < 0.05). Thereby, it can be concluded that mixing MTA with 80% DW and 20% PG increased the dentinal pH, which is positive for root resorption repair (AU).

Antimicrobial Activity and Physicochemical Properties of Antibiotic Pastes Used In Regenerative Endodontics.

The purpose of this study was to evaluate the pH, solubility and antimicrobial action of Calcium Hydroxide Paste (CH), Double Antibiotic Paste (metronidazole+ciprofloxacin-DAP), calcium hydroxide added to DAP (CH/DAP) and Triple Antibiotic Paste (metronidazole + ciprofloxacin+minocycline-TAP). pH (n=10) were measured by pHmeter. Root canals of acrylic teeth (n=10) were filled with the above-mentioned intracanal-dressings, immersed in ultrapure water, and solubility was measured by the difference between the initial and final volume (7,15 and 30 days) by using micro-computed tomography. Enterococcus faecalis biofilm was induced on bovine dentin disc surfaces (n=20), and treated with the pastes for 7 days. Percentage bacterial viability was verified by confocal microscope, with LIVE/DEAD dye. CH and CH/DAP presented the highest pH values. Regarding solubility, after 7 days, antibiotic groups presented significant volume loss. CH and CH/DAP showed no statistical difference compared with the Control in antimicrobial action against E. faecalis biofilm. However, TAP and DAP presented a significant percentage reduction in bacterial population. Due to high solubility of the pastes, renewing antibiotic dressings every 7 days, or using the medications for this period in regeneration protocols is recommended. DAP is indicated for killing E. faecalis in biofilm because it has antimicrobial action similar to TAP. Adding Calcium Hydroxide to DAP significantly decreased its antimicrobial action. In spite of its the low solubility and high pH values, the CH paste showed a low level of antimicrobial action against E. faecalis in biofilm.

Antimicrobial activity and physicochemical properties of antibiotic pastes used in regenerative endodontics

Abstract: The purpose of this study was to evaluate the pH, solubility and antimicrobial action of Calcium Hydroxide Paste (CH), Double Antibiotic Paste (metronidazole+ciprofloxacin-DAP), calcium hydroxide added to DAP (CH/DAP) and Triple Antibiotic Paste (metronidazole + ciprofloxacin+minocycline-TAP). pH (n=10) were measured by pHmeter. Root canals of acrylic teeth (n=10) were filled with the above-mentioned intracanal-dressings, immersed in ultrapure water, and solubility was measured by the difference between the initial and final volume (7,15 and 30 days) by using micro-computed tomography. Enterococcus faecalis biofilm was induced on bovine dentin disc surfaces (n=20), and treated with the pastes for 7 days. Percentage bacterial viability was verified by confocal microscope, with LIVE/DEAD dye. CH and CH/DAP presented the highest pH values. Regarding solubility, after 7 days, antibiotic groups presented significant volume loss. CH and CH/DAP showed no statistical difference compared with the Control in antimicrobial action against E. faecalis biofilm. However, TAP and DAP presented a significant percentage reduction in bacterial population. Due to high solubility of the pastes, renewing antibiotic dressings every 7 days, or using the medications for this period in regeneration protocols is recommended. DAP is indicated for killing E. faecalis in biofilm because it has antimicrobial action similar to TAP. Adding Calcium Hydroxide to DAP significantly decreased its antimicrobial action. In spite of its the low solubility and high pH values, the CH paste showed a low level of antimicrobial action against E. faecalis in biofilm.

Resumo A proposição deste estudo foi avaliar o pH, solubilidade e ação antimicrobiana da pasta de Hidróxido de Cálcio (HC), Pasta Diantibiótica (metronidazol+ciprofloxacina-DAP), Hidróxido de Cálcio adicionado a DAP (HC/DAP) e pasta Triantibiótica (metronidazol + ciprofloxacina + miociclina - TAP). a medição do pH e liberação de íons cálcio (n=10) foram avaliadas através de peagômetro e espectofotômetro de absorção atômica. Canais de dentes de acrílico (n=10) foram preenchidos com as medicações de canal mencionadas, imersos em água ultrapura e a solubilidade foi aferida pela diferença entre o volume inicial e final (7,15 e 30 dias) usando micro tomografia computadorizada. O biofilme de Enterococcus faecalis foi induzido em blocos de dentina bovina (n=20) e tratados com as pastas em questão por 7 dias. A porcentagem de bactérias vivas foi verificada usando o microscópio confocal com corante LIVE/DEAD. HC e HC/DAP apresentaram os maiores valores de pH e liberação de íons cálcio. A respeito da solubilidade, depois de 7 dias, os grupos com pastas antibióticas apresentaram perda de volume significante. HC e HC/DAP não tiveram diferenças estatísticas com o grupo controle na ação antimicrobiana contra biofilme. No entanto, a TAP e a DAP mostraram porcentagem significante de redução bacteriana. Conclusões: Devido à alta solubilidade das pastas, renovar as medicações antibióticas a cada 7 dias ou usa-las por esse período em protocolos regenerativos é recomendado. DAP é indicada para matar E. faecalis na forma de biofilme porque tem ação antimicrobiana similar a TAP. A adição do CH à DAP reduz significantemente sua ação antimicrobiana. Apesar da baixa solubilidade e altos valores de pH, a pasta de CH apresenta baixa ação antimicrobiana contra E. faecalis em biofilme.

Influence of Different Irrigation Solutions and Instrumentation Techniques on the Amount of Apically Extruded Debris.

OBJECTIVE: The objective of the present study was to evaluate the influence of different irrigation solutions on the amount of extruded residues apically, varying the instrumentation technique in manual, continuous rotation, or reciprocation motions. The amounts of residue for each irrigation solution was also assessed. METHODS: Two tests were performed. In the first test, 90 mandibular premolars were divided into nine groups (n=10). Each group was subjected to a different technique: ProTaper Universal, WaveOne Gold, or manual instruments, with different irrigation solutions [2.5% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX) gel, or distilled water]. During the preparation of the root canal, the apically extruded material was collected in previously weighed glass vials. In the second test, irrigation solutions were weighed separately with the same weighing method. Data were analyzed using the Kolmogorov-Smirnov, one-way and two-way ANOVA, Levene, Tukey, and Games-Howell tests. RESULTS: Apically extruded debris was observed in all groups. ProTaper Universal with continuous rotation using 2% CHX gel resulted in the greatest amount of debris (P<0.001). There were significant differences in the amounts of residue among the different groups (P<0.001). Moreover, when the weighing of the irrigation solutions was tested, the 2.5% NaOCl solution produced the greatest amount of residues compared with other irrigation solutions. CONCLUSION: Different irrigation solutions influenced the amount of apically extruded debris during the preparation of the canal among the different instrumentation techniques. The ProTaper technique using 2% CHX gel resulted in the greatest amount of apically extruded debris.

Shaping ability of rotary or reciprocating systems for oval root canal preparation: a micro-computed tomography study.

OBJECTIVES: To evaluate the shaping ability and cleaning after oval root canal preparation using one or more instruments in reciprocating or rotary motion. MATERIALS AND METHODS: Oval-shaped mandibular incisors were selected, based on the radiographic diameter (2 ≤ diameter ratio ≤ 4), and assigned according to root canal preparation (n = 18): single-file (Reciproc R40); two reciprocating files (Unicone size 20 and 40, .06 taper) or Mtwo rotary files until a size 40, .06 taper instrument. Root canal preparations were performed using an open root canal model. Scanning was performed before and after preparation using SkyScan 1176 with a voxel size of 17.42 µm. Volume, percentage of debris, and percentage of uninstrumented surface were analyzed in the entire root canal and in each root canal third. Data were compared using ANOVA and Tukey or Kruskal-Wallis and Dunn tests (α = 5%). RESULTS: The initial volume were similar among the groups (p > .05). Unicone preparation was associated with higher debris, increase in root canal volume and uninstrumented surface in entire root canal and in the middle third (P < .05). Mtwo was associated with lower uninstrumented surface in the entire root canal and in the cervical third. The apical third were similar for the three preparations. CONCLUSIONS: Unicone system using two instruments in reciprocating motion resulted in higher increase in volume. However, less remaining debris was observed when Reciproc single-file and Mtwo rotary systems were used. CLINICAL RELEVANCE: A preparation that volumetrically increases the root canal is not necessarily associated with better cleaning. Shaping and hard-tissue debris removal depends on root canal anatomy, kinematics, number of instruments, and instrument design.

Influência de substâncias irrigadoras em gel sobre o biofilme microbiano / Influence of gel irrigant agents in oral biofilm

Objetivo: o objetivo do presente estudo foi avaliar a ação antimicrobiana do hipoclorito de sódio a 1%, da clorexidina a 2% e do EDTA a 24% ­ todos na forma de gel ­, sobre o biofilme oral. Métodos: blocos de dentina bovina estéreis foram inseridos em um dispositivo intrabucal, o qual foi utilizado por um voluntário durante 3 dias. Após a formação do biofilme, os blocos foram imersos em 100 µl das diferentes substâncias avaliadas, durante 5 minutos. Após o tratamento, as amostras foram coradas com 50 µl de uma solução com iodeto de propídio e SYTO 9, e avaliadas em um microscópio confocal imediatamente após a remoção do agente antimicrobiano, gerando um total de 50 imagens por grupo. Os dados foram analisados por meio dos testes de Kruskal-Wallis e Dunn (α = 0,05). Resultados: diferenças estatísticas entre os grupos experimentais e controle foram observadas. O hipoclorito de sódio a 1% foi mais eficaz do que as outras substâncias avaliadas (p < 0,05). Ainda, a clorexidina a 2% reduziu a porcentagem de células vivas de forma mais significativa, comparada ao EDTA (p < 0,05). Conclusões: os agentes irrigantes utilizados nesse estudo não apresentaram capacidade de dissolução do biofilme formado in situ. No entanto, o hipoclorito de sódio apresentou melhores resultados, quanto comparado à clorexidina e ao EDTA.

Influência do cimento na radiopacidade de obturações com cone único / Sealer influence on radiopacity of single cone root canal fillings

Objetivo: o objetivo deste estudo foi avaliar a influência dos cimentos AH Plus e Endofill na radiopacidade de obturações em canais simulados, usando-se a técnica do cone único. Métodos: vinte blocos de resina com canais curvos simulados foram preparados até o instrumento rotatório ProTaper Universal F3. Após a irrigação final, os canais foram secos com cones de papel, e um cone de guta-percha F3 foi inserido no canal; em seguida, uma radiografia digital foi realizada para cada espécime. Os espécimes foram distribuídos aleatoriamente em dois grupos experimentais (n = 10), de acordo com cimento empregado. AH Plus e Endofill foram os cimentos associados à guta-percha para obturação dos canais. Após a presa final dos cimentos, novas imagens digitais foram realizadas, da mesma forma que as radiografias pré-operatórias. As imagens das radiografias antes e após a associação da guta-percha com o cimento foram sobrepostas e analisadas, para se registrar o número de pixels das imagens. A análise estatística foi realizada utilizando-se os testes t de Student e Wilcoxon, com nível de significância de 5%. Resultados: ambos os grupos apresentaram radiopacidade semelhante para a guta-percha (p > 0,05). No entanto, a adição do cimento aumentou significativamente (p < 0,05) a radiopacidade das imagens radiográficas. A radiopacidade foi aumentada em 68,10% com o cimento AH Plus e em 46,02% com o cimento Endofill, com diferença estatisticamente significativa entre os cimentos. Conclusões: os cimentos aumentaram significativamente a radiopacidade da obturação com a técnica do cone único. O cimento AH Plus foi mais radiopaco do que o cimento Endofill.

Effect of Using Different Vehicles on the Physicochemical, Antimicrobial, and Biological Properties of White Mineral Trioxide Aggregate.

INTRODUCTION: This study evaluated the physicochemical, antimicrobial, and biological properties of white mineral trioxide aggregate (MTA) mixed with aqueous and propylene glycol extracts of Arctium lappa L. and Casearia sylvestris Sw. METHODS: The setting-time test was performed according to American Society for Testing and Materials 266/2008 and flowability by American National Standards Institute/American Dental Association 57/2012 standard specifications. The following parameters were assessed: volumetric change by micro-computed tomography; pH level and calcium ion release measured after 3 hours and 1, 3, 7, and 15 days; antimicrobial effect by the dentin decontamination method with intratubular Enterococcus faecalis viability, verified by using confocal laser scanning microscopy; and biocompatibility by histologic-morphometric analyses of inflammatory infiltrate at subcutaneous implant sites after 15, 30, and 60 days. In addition, rat alveolar tissues with implants were processed to measure tumor necrosis factor-alpha and interleukin-10 cytokines by enzyme-linked immunosorbent assay. RESULTS: The plant extracts associated with MTA significantly increased the final setting time; however, they did not influence volumetric change (P > .05) and maintained medium alkalinity and calcium ion release. Propylene glycol extracts showed higher flowability. Casearia sylvestris increased the cementing effect against E. faecalis after 24-hour and 168-hour periods. Histologic evaluation of inflammatory infiltrate showed no significant differences between plant extracts groups and the distilled water group for all periods. Tumor necrosis factor-alpha and interleukin-10 expression was similar among groups (P > .05). CONCLUSIONS: Casearia sylvestris extracts increased the antimicrobial effect of MTA and did not influence biocompatibility but changed some physicochemical properties.

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.

Effectiveness of the ProTaper Next and Reciproc Systems in Removing Root Canal Filling Material with Sonic or Ultrasonic Irrigation: A Micro-computed Tomographic Study.

INTRODUCTION: The aim of this study was to evaluate the effectiveness of ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland) and Reciproc (VDW, Munich, Germany) systems in removing filling material from oval root canals using sonic or ultrasonic irrigation as additional cleaning methods. METHODS: Thirty-two human extracted mandibular premolars with oval canals were prepared using the ProTaper Universal system (Dentsply Maillefer) up to instrument F4 (40/.06) and then filled by the single-cone technique using Endofill sealer (Dentsply Maillefer). The teeth were randomly divided into 4 groups (n = 8) according to the instrumentation system and the additional cleaning method as follows: Reciproc 40 with ultrasonic activation, Reciproc 40 with sonic agitation, ProTaper Next (X2, X3, and X4) with ultrasonic activation, and ProTaper Next (X2, X3, and X4) with sonic agitation. All specimens were analyzed using micro-computed tomographic imaging before and after removal of the filling material and also after applying the additional cleaning methods. The data, in mm3 of remaining filling material, were analyzed by the Kruskal-Wallis, Dunn, and Mann-Whitney tests. RESULTS: None of the retreatment protocols completely removed the filling material from the root canals, and there was no significant difference between the instrumentation systems or between root thirds assessed in terms of the average volume of remaining filling material (P > .05). Likewise, no significant difference was observed between the additional cleaning methods in any of the root canal thirds assessed (P > .05). CONCLUSIONS: The ProTaper Next and Reciproc systems were equivalent with respect to effectiveness in removing filling material regardless of the additional cleaning method used. The additional cleaning methods were also equivalent and did not improve the removal of filling material significantly.

Effect of the Association of Nonsteroidal Anti-inflammatory and Antibiotic Drugs on Antibiofilm Activity and pH of Calcium Hydroxide Pastes.

INTRODUCTION: The objective of the present study was to evaluate the in vitro antibiofilm activity and pH of calcium hydroxide associated with different nonsteroidal anti-inflammatory drugs (NSAIDs). METHODS: The groups analyzed were as follows: group 1, calcium hydroxide paste with propylene glycol; group 2, calcium hydroxide paste with propylene glycol + 5% diclofenac sodium; group 3, calcium hydroxide paste with propylene glycol + 5% ibuprofen; group 4, calcium hydroxide paste with propylene glycol + 5% ciprofloxacin; and group 6, positive control (without medication). For analysis of the pH, the pastes were inserted into tubes and immersed in flasks containing ultrapure water. At the time intervals of 3, 24, 72, and 168 hours, the pH was measured with a calibrated pH meter. For microbial analysis, biofilm was induced in 30 bovine dentin blocks for 21 days. Subsequently, the pastes were placed on the blocks with biofilm for 7 days. Afterward, the pastes were removed by irrigation with sterile water, and the specimens were analyzed with a laser scanning confocal microscope with the 50 µL Live/Dead BacLight Bacterial Viability solution L7012 Kit (Molecular Probes, Inc, Eugene, OR). Data were subjected to statistical analysis at a significance level of 5%. RESULTS: The highest pH values were found for calcium hydroxide associated with ciprofloxacin in all periods analyzed. With the exception of pure calcium hydroxide paste, the other groups showed statistically significant differences (P < .05) in comparison with the positive control. CONCLUSIONS: The association of NSAIDs or antibiotic did not interfere with the pH of calcium hydroxide paste and increased the antimicrobial action of calcium hydroxide paste against Enterococcus faecalis biofilm formation.

Evaluation of Mesial Root Canals of Mandibular Molars Obturated with Gutta-Percha and Resilon Techniques.

OBJECTIVE: The aim of this study was to evaluate the obturation of mesial root canals of mandibular first molars performed with different filling techniques and materials (gutta-percha and resilon). METHODS: Seventy-eight mesial root canals of human mandibular first molars were prepared using the K3 rotary system, and the apical preparation was set up to size 35.04. The root canals were obturated with single cone, System B, Thermafil and Real Seal 1 techniques using either gutta-percha/ThermaSeal Plus (n=13) or Resilon/Real Seal SE (n=13). Rhodamine B dye was incorporated into the sealers. Each specimen was horizontally sectioned at 2 milimeters (mm), 4 mm and 6 mm from the apex, and the samples were examined under a stereomicroscope to evaluate the presence and type of isthmuses and the percentage areas of gutta-percha/Resilon, sealer and voids. Confocal laser scanning microscopy (CLSM) was used to evaluate the sealer penetration into dentinal tubules. The Kruskal-Wallis and Dunn's tests were used to analyse the stereomicroscope data, while the ANOVA and Tukey tests were used to analyse the CLSM data (P<0.05). RESULTS: Thermafil and Real Seal 1 fillings showed more gutta-percha/Resilon and less sealer (P<0.05) at the 2 mm level, but the percentage of voids was similar in all groups (P>0.05). At the 4 mm level, more sealer (P<0.05) was found in the single cone groups using both materials. The System B groups exhibited better performance at the 6 mm level. The percentage of sealer penetration showed no statistically significant differences among the obturation techniques for all evaluated levels. Similar results (P>0.05) were found for both material/sealers. CONCLUSION: None of the materials or techniques completely filled the mesial root canals of mandibular molars, but the plasticised techniques were more efficient. The obturations using both materials and sealers were similar.

Influência do contato com sangue e soro fisiológico na solubilidade, pH e constituição química do MTA / Influence of contact with blood and saline on solubility, pH and chemical composition of MTA

Objetivo: o objetivo deste estudo foi avaliar a solubilidade, pH e composição química do MTA branco em contato com sangue e soro fisiológico. Métodos: trinta réplicas de incisivos centrais superiores em acrílico, com retrocavidades com 3 mm de profundidade, foram preenchidas com MTA branco. Os espécimes foram individualmente inseridos em microtubos e divididos em três grupos (n = 10): no Grupo 1, as amostras não foram expostas a líquidos (grupo controle); no grupo 2, os microtubos receberam 1 mL de soro fisiológico; e no Grupo 3, receberam 1 mL de sangue humano fresco. As amostras foram armazenadas a 37°C durante 24 horas. A solubilidade foi avaliada volumetricamente, de modo que os espécimes foram escaneados por Micro-CT e individualmente imersos em 10 mL de água ultrapura; após 168 horas, novos escaneamentos foram realizados. O nível de pH foi mensurado após 168 horas. Secções das amostras com 2 mm de espessura foram analisadas por meio de espectroscopia de energia dispersiva, para avaliar a composição iônica. Os dados foram analisados estatisticamente pelos testes ANOVA e Tukey. Resultados: a solubilidade foi similar (p > 0,05) para todos os grupos. Após 168 horas, o pH foi significativamente maior para o Grupo 2, em comparação ao Grupo 3 (p < 0,05). Quanto à composição iônica, foi encontrada maior concentração de cálcio e o contato com sangue não interferiu na liberação de íons de cálcio. Conclusão: o contato do sangue e soro fisiológico com o MTA não influenciou na solubilidade, ambos favoreceram um pH alcalino, com o aumento da liberação de íons cálcio, com pequenas variações na composição iônica.