Effect of nickel-titanium alloys on root canal preparation and on mechanical properties of rotary instruments.

The aim of this study was to evaluate the quality of curved root canal preparation, torsional fatigue, and cyclic fatigue of rotary systems manufactured with different NiTi alloys. Ninety single-rooted canals with curvatures of 15° to 30o were scanned and divided into three groups according to the rotary system used: BT-Race (BTR) - 10.06, 35.00, 35.04; SequenceRotaryFile (SRF) - 15.04, 25.06, 35.04; and ProDesignLogic (PDL) - 25.01, 25.06, 35.05. Each system was used on three specimens. The teeth were prepared, scanned, and analyzed to assess increase in volume, transportation, and centering ability of the root canal. Torsional fatigue of glide path instruments (BTR 10.06, SRF 15.04 and PDL 25.01) and cyclic fatigue of the finishing instrument (BTR 35.04, SRF 35.04 and PDL 35.05) were obtained by analyzing completely new instruments (n = 10) and instruments after they had been used three times (n = 10). After the torsional and cyclic fatigue tests, the fractured surface of the new and used instruments were examined by scanning electron microscopy. Increase in volume, canal transportation, and centering ability showed no significant differences among the groups (p > 0.05). The torsional test showed that SRF 15.04 produced the highest torque values for both new and used instruments, followed by PDL 25.01 and BTR 10.06 (p < 0.05). PDL 25.01, both new and used, exhibited higher values of angular deflection followed by SRF 15.04 and BTR 10.06 (p < 0.05). As regards cyclic fatigue, use of PDL 35.05, both new and used, required a longer time and larger number of cycles than did SRF 35.04 and BTR 35.04 (p < 0.05). Clinical use affected the torsional fatigue of BTR; however, cyclic fatigue was not significantly affected (p < 0.05). All rotary systems were able to prepare the curved canals satisfactorily and were used safely on the three specimens. Relative to torsional fatigue, SRF 15.04 exhibited a higher torque, and PDL 25.01, higher angular deflection. BTR 10.06 was the most affected by clinical use. PDL 35.05 showed greater resistance to cyclic fatigue.

Effect of nickel-titanium alloys on root canal preparation and on mechanical properties of rotary instruments

Abstract The aim of this study was to evaluate the quality of curved root canal preparation, torsional fatigue, and cyclic fatigue of rotary systems manufactured with different NiTi alloys. Ninety single-rooted canals with curvatures of 15° to 30o were scanned and divided into three groups according to the rotary system used: BT-Race (BTR) - 10.06, 35.00, 35.04; SequenceRotaryFile (SRF) - 15.04, 25.06, 35.04; and ProDesignLogic (PDL) - 25.01, 25.06, 35.05. Each system was used on three specimens. The teeth were prepared, scanned, and analyzed to assess increase in volume, transportation, and centering ability of the root canal. Torsional fatigue of glide path instruments (BTR 10.06, SRF 15.04 and PDL 25.01) and cyclic fatigue of the finishing instrument (BTR 35.04, SRF 35.04 and PDL 35.05) were obtained by analyzing completely new instruments (n = 10) and instruments after they had been used three times (n = 10). After the torsional and cyclic fatigue tests, the fractured surface of the new and used instruments were examined by scanning electron microscopy. Increase in volume, canal transportation, and centering ability showed no significant differences among the groups (p > 0.05). The torsional test showed that SRF 15.04 produced the highest torque values for both new and used instruments, followed by PDL 25.01 and BTR 10.06 (p < 0.05). PDL 25.01, both new and used, exhibited higher values of angular deflection followed by SRF 15.04 and BTR 10.06 (p < 0.05). As regards cyclic fatigue, use of PDL 35.05, both new and used, required a longer time and larger number of cycles than did SRF 35.04 and BTR 35.04 (p < 0.05). Clinical use affected the torsional fatigue of BTR; however, cyclic fatigue was not significantly affected (p < 0.05). All rotary systems were able to prepare the curved canals satisfactorily and were used safely on the three specimens. Relative to torsional fatigue, SRF 15.04 exhibited a higher torque, and PDL 25.01, higher angular deflection. BTR 10.06 was the most affected by clinical use. PDL 35.05 showed greater resistance to cyclic fatigue.

Profile of host cell responses to exposure to stressed bacteria in planktonic; dislodged, and intact biofilm mode.

The host defense response to microbial challenge emerging from the root canal system leads to apical periodontitis. The aim of this study was to evaluate the expression of inflammatory cytokines and Nitric Oxide (NO) by macrophages after interaction with Enterococcus faecalis in the: plankton and dislodged biofilm mode; intact biofilm mode stimulated by calcium hydroxide (CH), CH and chlorhexidine (CHX) or Triple Antibiotic Paste (TAP). For this purpose, culture of macrophages from monocytes in human peripheral blood (N=8) were exposed to the different modes of bacteria for 24 hours. Subsequently, the cytokines, such as, Tumor Necrotic Factor- alfa (TNF-α), interleukin (IL)-1ß, IL-6, IL-10; and NO were quantified by Luminex xMAP and Greiss reaction, respectively. In addition to the potential therapeutic effects of the intracanal medication, their antimicrobial activity against Enterococcus faecalis biofilm were also tested in vitro by confocal microscopy. The experiments` data were analyzed by the Kruskal-Wallis test with the Dunn post hoc test (α < 0.05). Bacteria in dislodged biofilm mode were shown to be more aggressive to the immune system than bacteria in plankton mode and negative control, inducing greater expression of NO and TNF-α. Relative to bacteria in intact biofilm mode, the weakest antimicrobial activity occurred in Group CH. In Groups CH/CHX and TAP the percentage of dead bacteria was significantly increased to the same extent. Interestingly, the biofilm itself did not induce the release of pro-inflammatory cytokines - except for NO - while the biofilm treated with TAP and CH based pastes enhanced the levels of IL-6 and TNF-α; and IL-1 ß, respectively. In contrast, the levels of a potent anti-inflammatory (IL-10) were increased in Group TAP.

Profile of host cell responses to exposure to stressed bacteria in planktonic; dislodged, and intact biofilm mode

Abstract The host defense response to microbial challenge emerging from the root canal system leads to apical periodontitis. The aim of this study was to evaluate the expression of inflammatory cytokines and Nitric Oxide (NO) by macrophages after interaction with Enterococcus faecalis in the: plankton and dislodged biofilm mode; intact biofilm mode stimulated by calcium hydroxide (CH), CH and chlorhexidine (CHX) or Triple Antibiotic Paste (TAP). For this purpose, culture of macrophages from monocytes in human peripheral blood (N=8) were exposed to the different modes of bacteria for 24 hours. Subsequently, the cytokines, such as, Tumor Necrotic Factor- alfa (TNF-α), interleukin (IL)-1β, IL-6, IL-10; and NO were quantified by Luminex xMAP and Greiss reaction, respectively. In addition to the potential therapeutic effects of the intracanal medication, their antimicrobial activity against Enterococcus faecalis biofilm were also tested in vitro by confocal microscopy. The experiments` data were analyzed by the Kruskal-Wallis test with the Dunn post hoc test (α < 0.05). Bacteria in dislodged biofilm mode were shown to be more aggressive to the immune system than bacteria in plankton mode and negative control, inducing greater expression of NO and TNF-α. Relative to bacteria in intact biofilm mode, the weakest antimicrobial activity occurred in Group CH. In Groups CH/CHX and TAP the percentage of dead bacteria was significantly increased to the same extent. Interestingly, the biofilm itself did not induce the release of pro-inflammatory cytokines - except for NO - while the biofilm treated with TAP and CH based pastes enhanced the levels of IL-6 and TNF-α; and IL-1 β, respectively. In contrast, the levels of a potent anti-inflammatory (IL-10) were increased in Group TAP.

Resumo A resposta de defesa do hospedeiro ao desafio microbiano que emerge do sistema de canais radiculares leva à periodontite apical. Os objetivos deste estudo foram avaliar a expressão de citocinas pró e anti-inflamatórias e Óxido Nítrico (NO) por macrófagos após interação com Enterococcus faecalis no modo: planctônio e de biofilme desalojado; biofilme intacto estimulado por hidróxido de cálcio (CH), CH e clorexidina ou Pasta Tri Antibiótica (TAP). Para isto, a cultura de macrófagos originados de monócitos do sangue periférico de humanos (N=8) foi exposta aos diferentes tipos de bactéria por 24 horas. Então, a quantificação da produção de of Fator de Necrose Tumoral- alfa (TNF-α), interleucina (IL)-1β, IL-6, IL-10 e NO por macrófagos se deu por meio do Luminex xMAP e reação de Greiss, respectivamente. Além dos potenciais efeitos terapêuticos desses compostos, sua atividade antimicrobiana contra E. faecalis também foi testada através microscopia confocal. Os dados dos experimentos foram analisados através do teste de Kruskal-Wallis com Dunn`s post hoc (α < 0.05). Bactéria em modo de biofilme desalojado se mostrou mais agressivo ao sistema imune que as bactérias planctônicas e controle negativo induzindo a maior excreção de NO e TNF-α. Em relação ao biofilme intacto, a atividade antimicrobiana mais fraca ocorreu no grupo de CH. Os grupos CHX e TAP aumentaram significativamente a porcentagem de bactérias mortas na mesma extensão. Interessantemente, o biofilme por ele mesmo não induziu a liberação de citocinas pro-inflamatórias - exceto por NO - enquanto que o biofilme tratado com TAP ou pastas a base de CH aumentaram os níveis de IL-6; e TNF-α e IL-1 β respectivamente. Em contraste, os níveis da potente citocina anti-inflamatória (IL-10) foram aumentados pelo grupo TAP.

Cyclic Fatigue Resistance of Nickel-Titanium Reciprocating Instruments after Simulated Clinical Use.

INTRODUCTION: The aim of this study was to evaluate the cyclic fatigue resistance of different heat-treated nickel-titanium reciprocating instruments in 2 different situations: new and used instruments after preparing 3 curved canals. METHODS: A total sample of 60 nickel-titanium instruments of 3 systems (n = 20 per system) were used in this study: ProDesign R (tip 25, 0.06 taper; Easy Dental Equipment, Belo Horizonte, Brazil), Reciproc Blue (tip 25, 0.08v taper; VDW, Munich, Germany), and WaveOne Gold (tip 25, 0.07v taper; Dentsply Sirona, Ballaigues, Switzerland). Thirty new instruments (n = 10 per system) were used to prepare 90 curved single-rooted mandibular premolars (n = 30). Each instrument was used to prepare 3 root canals, and after each canal preparation the instrument was ultrasonic cleaned and submitted to autoclave sterilization procedures. The other 30 instruments (n = 10 per system) were kept without use. Then, the new and used instruments were subjected to the cyclic fatigue test in an artificial canal with a 30° angle and a 5-mm radius of curvature. The time and number of cycles to fatigue were recorded. Data were analyzed using the unpaired t test for intragroup comparison. For intergroup comparison, analysis of variance and the Tukey test for multiple comparisons were used. RESULTS: The intergroup comparison of new instruments showed that ProDesign R had the highest cyclic fatigue resistance followed by Reciproc Blue and WaveOne Gold (P < .05). Regarding the used instruments, WaveOne Gold had the lowest cyclic fatigue resistance (P < .05). The intragroup comparison between new and used instruments showed that WaveOne Gold and ProDesign R presented a significant reduction in the cyclic fatigue resistance after simulated clinical use (P < .05); no difference was found with the Reciproc Blue instruments (P > .05). CONCLUSIONS: ProDesign R had the highest cyclic fatigue resistance, whereas WaveOne Gold had the lowest for new and used instruments. Simulated clinical use affected the cyclic fatigue resistance of ProDesign R and WaveOne Gold but not of Reciproc Blue instruments.

Comparação de diferentes métodos de inserção da pasta de hidróxido de cálcio para preenchimento de canais laterais simulados: estudo in vitro / Comparison of different methods for insertion of calcium hydroxide paste in the filling of simulated lateral canals: in vitro evaluation

Avaliar, em micro-CT, diferentes métodos de inserção da pasta de hidróxido de cálcio para preenchimento de canais laterais simulados em blocos de acrílico. Métodos: Foram utilizados 72 blocos de acrílico com canais laterais simuladas nas porções cervical, média e apical, os quais foram preenchidos com a pasta de hidróxido de cálcio de acordo com os seguintes métodos (n=12): Grupo 1 - lima tipo K #30; Grupo 2 - espiral de Lentulo; Grupo 3 - agitação ultrassônica; Grupo 4 - agitação sônica com EndoActivator; Grupo 5 - seringa + Capillari TIPS; e Grupo 6 - agitação com EasyClean em baixa rotação. Para os grupos que receberam agitação, o canal principal foi preenchido com a pasta utilizando seringa e Capillari Tips. Antes e após o preenchimento, os dentes foram escaneados em micro-CT (SkyScan 1174) e as imagens obtidas foram comparadas utilizando-se o software CTan. O volume de medicação intracanal no interior dos canais simulados foi mensurado e, em seguida, obtida a porcentagem de penetração. Os dados foram submetidos à comparação estatística (p<0,05). Resultados: Os grupos EndoActivator e ultrassom apresentaram resultados significativamente melhores do que a lima #30 nos três níveis analisados, assim como o EasyClean nos terços cervical e médio, e a Lentulo no terço apical, em relação ao Grupo 1 (p <0,05). Nas demais comparações e na análise intragrupos, não houve diferenças significativas (p>0,05). Conclusão: Os métodos de agitação da medicação intracanal, especialmente o ultrassom, proporcionaram uma maior porcentagem de penetração dela em canais laterais simulados (AU).

Objective: The objective of this study was to analyze, in micro-CT, the capacity of different methods for insertion of calcium hydroxide paste in the filling of lateral canals simulated in blocks of acrylic. Methods: A total of 72 acrylic blocks with lateral canals simulated in the coronal, middle and apical portions, were used and filled with calcium hydroxide paste, according to the following methods (n = 12): Group 1 - #30 K-file; Group 2 - Lentulo spiral; Group 3 - Ultrasonic agitation; Group 4 - Sonic agitation with EndoActivator; Group 5 - Syringe + Capillary Tips; Group 6 - Agitation with Easy Clean at low speed. For the groups that received agitation, the blocks were filled with the aid of a syringe and Capillary Tips. Each sample was scanned with SkyScan 1174, before and after the filling procedures, and the volume of calcium hydroxide was measured using CTAN software. The percentage of penetration of intracanal medication inside the simulated canals was calculated. Data were statistically compared (p < 0.05). Results: The agitation with EndoActivator and ultrasonic insert promoted a greater penetration of paste with significant statistical differences in relation to the #30 K-file group in the 3 levels analyzed (p < 0.05). Other statistical differences occurred in the comparison between the Easy Clean group and #30 K-file group in the coronal and middle thirds and in the comparison between Lentulo spiral group and #30 K-file group in the apical (p < 0.05). Conclusion: Methods which use agitation devices , such as ultrasonic insert, promoted higher filling of calcium hydroxide in simulated lateral canals (AU).

Influence of foraminal enlargement on the apical extrusion of filling material: Volumetric analysis using micro-computed tomography.

The aim of this study was to compare the root canal instrumentation techniques that involve foraminal enlargement versus those not involving it, in regard to the apical extrusion of filling material, using micro-computed tomography (micro-CT). Twenty-two premolars with single canals were instrumented using the ProTaper Universal System and then randomly divided into two groups (n = 11): Group NFE, without foraminal enlargement, and Group FE, with foraminal enlargement. Instrumentation was performed up to 1 mm short of the apical foramen, and foraminal patency was maintained at each instrument change in both groups. Prior to obturation, the apical portion of the specimens was wrapped in adhesive paper to ensure complete separation between apex and extruded material. The canals were filled according to the continuous wave of condensation technique. The apically extruded material was collected and measured using micro-CT. Extrusion in Group FE was significantly higher than in Group NFE (0.928 mm3 vs. 0.148 mm3 ; P < 0.001).

Clinical and self-perceived oral health assessment of elderly residents in urban, rural, and institutionalized communities.

OBJECTIVES: This study aims to evaluate the self-perception of oral health according to the physical, psychosocial and pain/discomfort dimensions related to clinical conditions and orofacial pain of elderly people living in three different environments. METHODS: This was an observational, cross-sectional, quantitative study with a population-based approach and nonprobabilistic convenience sampling that included 81 elderly people: 27 resided in institutional homes for elderly individuals, 27 resided in an urban area and 27 resided in a rural area in the interior of Paraíba (PB) in northeastern Brazil. RESULTS: The Geriatric Oral Health Assessment Index (GOHAI) was used to assess self-perception of oral health, while the Questionnaire for Screening of Patients with Temporomandibular Disorders (QST/TMD) was used to assess the influences of orofacial pain and the biofilm indexes of teeth and prostheses. There was a statistically significant difference in the GOHAI scores among the places of residence, with the worst values associated with the rural area. According to the QST/TMD, the majority of individuals were affected by TMDs, with statistical differences for both sex and income. CONCLUSION: The biofilm analysis showed a higher incidence of clinical conditions in the rural population. The place of residence also influenced self-perception and the clinical oral health condition of elderly people; the rural population presented the worst results.

Tratamento não cirúrgico para remoção de instrumento fraturado e guta-percha extravasada, com o uso do Masserann EndoKit / Non-surgical treatment for removing fractured instrument and extravasated gutta-percha, by using the Masserann EndoKit

Objetivo: o objetivo deste artigo é relatar um caso clínico em que um instrumento fraturado e a guta-percha extravasada foram removidos via canal. Relato de caso: paciente do sexo masculino, com 38 anos de idade, foi encaminhado para avaliação do incisivo lateral superior direito (dente #12). O paciente apresentava dor à palpação na região apical e ausência de sintomatologia espontânea. O exame radiográfico revelou a presença de cone de guta-percha extravasado, uma espiral de Lentulo fraturada, além de lesão periapical no dente #12. O retratamento endodôntico foi o procedimento de escolha, na tentativa de remover os dois materiais. A espiral de Lentulo foi removida com Masserann Endokit; e o cone de guta-percha, utilizando limas Hedstroen. Após realizar a instrumentação e o preenchimento do conduto com pasta de hidróxido de cálcio com iodofórmio, constatou- se a presença de reabsorção no terço apical. Depois de dois meses, observou-se redução da lesão; utilizou-se, então, MTA na região da reabsorção, e o conduto foi obturado com cone de guta-percha e cimento endodôntico Sealer 26. Conclusão: controles clínicos e radiográficos foram realizados após dois, quatro e oito anos, demonstrando reparo na região apical e ausência de sintomatologia (AU).

The objective of this article was to report a clinical case of finding a fractured instrument and over-extended guttapercha of a tooth, which were removed via the canal. The patient, a 38-year-old man, was referred for treatment of the right maxillary lateral incisor (tooth 7). The patient presented pain on palpation at the apical level and absence of spontaneous symptomatology. Radiographic examination revealed the presence of a over-extended gutta-percha cone, a fractured Lentulo spiral and periapical lesion in tooth 7. Endodontic retreatment was the chosen procedure in an attempt to remove both materials. The Lentulo spiral was removed by means of the Masserann Endokit, and the gutta-percha cone by using Hedstroen files. While performing instrumentation, and filling the canal with calcium hydroxide with iodoform, the presence of resorption in the apical third was verified. After 2 months, reduction of the lesion was observed, thus MTA was placed in the area of resorption and the remainder of the canal was filled with a gutta-percha cone and Sealer 26 cement. Clinical and radiographic controls performed after 2, 5 and 7 years showed repair of the area and absence of symptomatology (AU).

Polymerization shrinkage, microhardness and depth of cure of bulk fill resin composites.

The present in vitro study assessed the polymerization shrinkage/PS, Knoop microhardness/KHN and depth of cure/DC of 9 different resin composites : Filtek Bulk Fill Flowable (FBF), Surefill SDR flow (SDR), Xtra Base (XB), Filtek Z350XT Flowable (Z3F), Filtek Bulk Fill Posterior (FBP), Xtra Fill (SF), Tetric Evo Ceram Bulk Fill (TBF), Admira Fusion Xtra (ADM), and Filtek Z350XT (Z3XT). PS was assessed with a µ-CT machine, scanning 64 mm3 samples (n=8) before and after 20 s curing. KHN and DC were performed with a microhardness tester (n=8 for each group) right after 20 s light curing, with 3 readings per depth at every 0.5 mm. Low viscosity resin composites showed lower KHN values when compared with high viscosity resins. Z3XT showed the highest microhardness among the tested resin composites. Z3XT and Z3F showed lower DC when compared with bulk fill resin composites. All bulk fill resin composites presented depth of cure higher than 4.5 mm and similar or lower PS than conventional resin composites.

Comparison of efficiency of the retreatment procedure between Wave One Gold and Wave One systems by Micro-CT and confocal microscopy: an in vitro study.

INTRODUCTION: To compare, by Micro-CT and confocal laser scanning microscopy (CLSM), the ability of the Wave One Gold and Wave One systems to remove filling material from mesial canals of mandibular molars, effective time spent; quantity of extruded material, and percentage of sealer in the dentinal tubules after retreatment and re-obturation procedures. MATERIALS AND METHODS: Ten first mandibular molars (n = 20 mesial canals) were prepared and filled with gutta-percha and Endofill sealer mixed with Rhodamine B dye using the single cone technique. After 7 days, the canals were scanned using a high-definition micro-computer tomography with 19-mm voxel size and divided into two groups (n = 10) according to the system used in retreatment: group 1, Wave One (WO), and group 2, Wave One Gold (WG). After removing filling material with the primary file of each system, the WO 40/.08 and WG 35/.06 files were used. After using each file, a new scanning was performed and the residual filling material and extruded filling material were measured. The effective time spent to remove the canal filling was measured after each instrument. After retreatment, the teeth were re-obturated with gutta-percha and AH Plus sealer mixed with fluorescein dye using the single-cone technique. The roots were sectioned at 2, 4 and 6 mm and analysed by CLSM to measure the percentage of remaining sealer and the sealer of the new root canal filling. The data were statistically compared (P < 0.05). RESULTS: Both systems presented a similar volume of filling material remaining in the canals after the use of the two instruments, similar residual and new material in the dentinal tubules, and similar extrusion of material (P > 0.05). When using WO 25, the operator spent significantly less effective time than when using WG 25 (P < 0.05); however, use of WG 35 and WO 40 required a similar time to remove filling material from the canals (P > 0.05). CONCLUSIONS: Neither of the two systems removed all the filling material. The WG system presented similar ability in removing filling and extruded material in comparison with WO system. The effective time spent was shorter for WO 25 than for WG 25. CLINICAL RELEVANCE: Wave One Gold can be an alternative to perform retreatment considering that in comparison with Wave One, there was no difference in filling material removal capacity and extruded materials. There was only difference in the effective time spent, in which the operator spent more time with WG 25 than with WO 25.

Clinical and self-perceived oral health assessment of elderly residents in urban, rural, and institutionalized communities

OBJECTIVES: This study aims to evaluate the self-perception of oral health according to the physical, psychosocial and pain/discomfort dimensions related to clinical conditions and orofacial pain of elderly people living in three different environments. METHODS: This was an observational, cross-sectional, quantitative study with a population-based approach and nonprobabilistic convenience sampling that included 81 elderly people: 27 resided in institutional homes for elderly individuals, 27 resided in an urban area and 27 resided in a rural area in the interior of Paraíba (PB) in northeastern Brazil. RESULTS: The Geriatric Oral Health Assessment Index (GOHAI) was used to assess self-perception of oral health, while the Questionnaire for Screening of Patients with Temporomandibular Disorders (QST/TMD) was used to assess the influences of orofacial pain and the biofilm indexes of teeth and prostheses. There was a statistically significant difference in the GOHAI scores among the places of residence, with the worst values associated with the rural area. According to the QST/TMD, the majority of individuals were affected by TMDs, with statistical differences for both sex and income. CONCLUSION: The biofilm analysis showed a higher incidence of clinical conditions in the rural population. The place of residence also influenced self-perception and the clinical oral health condition of elderly people; the rural population presented the worst results.

Comparisons by microcomputed tomography of the efficiency of different irrigation techniques for removing dentinal debris from artificial grooves.

AIM: The aim of this study was compare the capacity of different irrigation protocols for debris removal from artificial grooves and assess the effectiveness of Easy Clean used in different kinematics by means of micro-CT. METHODOLOGY: Fifty acrylic prototyped maxillary incisors were instrumented and included in a muffle. The specimens were longitudinally sectioned, and a longitudinal groove was made on the inner surface of the root canal in one of hemisections, and the dentin debris was inserted into the grooves. The specimens were divided into five groups (n = 10): G1: Conventional with open-ended needle; G2: Conventional with double side-vented needle; G3: Easy Clean in reciprocating movement; G4: Easy clean in continuous rotation (ECCR); and G5: Passive ultrasonic irrigation (PUI). All specimens were scanned using microcomputed tomography before and after the irrigation technique and calculated the volume (mm3) of dentin debris. The paired t-test and post hoc Tukey test were the statistical tests used, with significance set at 5%. RESULTS: There were no significant difference (P > 0.05) between PUI and ECCR. ECCR was significantly (P < 0.05) more effective than the groups of conventional irrigation techniques. CONCLUSIONS: PUI and ECCR favored the removal of a larger volume of dentin debris from the groove.

Effect of ultrasonic agitation on push-out bond strength and adaptation of root-end filling materials.

OBJECTIVES: This study evaluated the effect of ultrasonic agitation of mineral trioxide aggregate (MTA), calcium silicate-based cement (CSC), and Sealer 26 (S26) on adaptation at the cement/dentin interface and push-out bond strength. MATERIALS AND METHODS: Sixty maxillary canines were divided into 6 groups (n = 10): MTA, S26, and CSC, with or without ultrasonic activation (US). After obturation, the apical portions of the teeth were sectioned, and retrograde cavities were prepared and filled with cement by hand condensation. In the US groups, the cement was activated for 60 seconds: 30 seconds in the mesio-distal direction and 30 seconds in the buccal-lingual direction, using a mini Irrisonic insert coupled with the ultrasound transducer. After the materials set, 1.5-mm thick sections were obtained from the apexes. The presence of gaps and the bond between cement and dentin were analyzed using low-vacuum scanning electron microscopy. Push-out bond strength was measured using a universal testing machine. RESULTS: Ultrasonic agitation increased the interfacial adaptation of the cements. The S26 US group showed a higher adaptation value than MTA (p < 0.05). US improved the push-out bond strength for all the cements (p < 0.05). CONCLUSIONS: The US of retrograde filling cements enhanced the bond to the dentin wall of the root-end filling materials tested.

Influence of the calcium hydroxide paste vehicle on penetration into lateral canals / Influência do veículo da pasta de hidróxido de cálcio na penetração em canais laterais

Objective: The aim of this study was to use Micro computed tomography (micro-CT) to evaluate the influence of the type of vehicle associated with calcium hydroxide on its ability to penetrate simulated lateral canals. Material and Methods: 30 acrylic blocks with simulated lateral canals comprising apical, middle and cervical thirds were used in the in vitro study. The blocks were divided into 3 groups (n = 10) according to the type of vehicle used (chlorhexidine, distilled water and propylene glycol) in the calcium hydroxide slurry, which was inserted in the respective group of simulated canals with a K# 30 file and then agitated with an ultrasonic tip. The blocks were scanned by micro-computed tomography (micro-CT) before and after insertion of the medication. The images obtained were reconstructed and analyzed to obtain the initial volume of lateral canals and the volume of medication that penetrated into them. Results: In the intragroup analysis, both distilled water and chlorhexidine 2% were observed to present statistical difference in all thirds of the canal. Propylene glycol showed no intragroup difference. In the inter-group analysis, the propylene glycol paste presented higher values of penetration into the simulated lateral canals than the other groups (p <0.05). Conclusion: Propylene glycol used as vehicle of the calcium hydroxide paste provided better penetration results in simulated lateral canals (AU).

Objetivo: O objetivo desse estudo foi avaliar por meio da microtomografia computadorizada a influência do tipo de veículo associado ao hidróxido de cálcio na capacidade de penetrar em canais laterais simulados. Material e Métodos: No estudo foram utilizados 30 blocos de acrílico com canais laterais simulados nos terços apical, médio e cervical. Os blocos foram divididos em 3 grupos (n=10) de acordo com o tipo de veículo utilizado (clorexidina, água destilada e propilenoglicol) na pasta de hidróxido de cálcio, foram inseridos com auxílio de uma lima tipo k 30 e em seguida agitadas com ultrassom. Os blocos foram escaneados em microtomografia computadorizada antes e após a inserção da medicação. As imagens obtidas foram reconstruídas e analisadas obtendo o volume inicial dos canais laterais e o volume de medicação que penetrou nos mesmos. Resultados: Na análise estatística intragrupo observou-se que tanto a água destilada quanto a clorexidina 2% apresentaram diferença estatística em todos os terços do canal. O propilenoglicol não apresentou diferença intragrupo. Já na análise entre os grupos, a pasta com propilenoglicol apresentou maior penetração nos canais laterais simulados (p<0,05). Conclusão: O propilenoglicol utilizado como veículo da pasta de hidróxido de cálcio permitiu melhores resultados de penetração em canais laterais simulados. (AU).

Effect of the irrigation protocols on the elimination of dentin debris from simulated lateral canals / Efeito do método de irrigação na eliminação de debris dentinários em canais late-rais simulados

Objective: Computed microtomography was used to evaluate the capacity of debris removal from simulated lateral canals, in conventional irrigation, passive ultrasonic irrigation (PUI), continuous passive irrigation (CUI), Endoactivator and EasyClean, for both types of motion (continuous and reciprocating). Material and Methods: Sixty acrylic incisors with 3 simulated lateral canals per tooth (cervical, middle and apical third) were instrumented with Reciproc 40/06 and then filled with dentin debris. The teeth were scanned and divided into 6 groups (n = 10) according to the irrigation protocol: G1 - conventional, G2 - PUI, G3 - CUI, G4 - Endoactivator, G5 - EasyClean continuous rotation and G6 - EasyClean reciprocating. After the irrigation protocols, the samples were scanned again. The initial and final volume images were analyzed and the percentage of debris removal were found for each group in all levels. Results: There were significant differences between the initial and final volume of debris after the protocols, with the exception of conventional irrigation group in the apical and cervical thirds, EasyClean reciprocating in the middle and cervical thirds, and CUI in the middle third. In the analysis between the groups: in the apical third, Endoactivator and PUI removed more debris than CUI (p < 0.05); in the middle and cervical thirds, PUI was more efficient than conventional irrigation, EasyClean reciprocating and CUI (p < 0.05). Conclusion: No method completely removed the debris. PUI was the method that showed greater effectiveness in cleaning the lateral canals. (AU)

Objetivo: O objetivo desse estudo foi avaliar a capacidade de remoção de debris de canais laterais simulados através da microtografia computadorizada (microCT), na irrigação convencional, ultrassônica passiva (IUP), ultrassônica contínua (IUC), Endoactivator e EasyClean, para os dois tipos de movimento (contínuo ou alternado). Material e Métodos: Sessenta incisivos de acrílico com três canais late-rais simulados por dente (terço cervical, médio e apical) foram instrumentados com Reciproc 40/06 e preenchidos com debris de dentina bovina. Os dentes fo-ram escaneados e divididos em 6 grupos (n = 10): G1 - convencional, G2 - IUP, G3 - IUC, G4 - Endoactivator, G5 - EasyClean rotação continua e G6 - EasyClean reciprocante. Depois do protocolo de irrigação, as amostras foram novamente escaneadas. O volume inicial e final das imagens foram analisados e o percentual de debris removidos foram encontrados para cada grupo nos três terços. Resultados: Todos os grupos obtiveram diferenças significantes após o proto-colo de irrigação, com exceção do grupo da irrigação convencional nos terços apical e cervical, EasyClean reciprocante (médio e cervical) e IUC no terço médio. Na análise intragrupo para o terço apical, EndoActivator e IUP removeram mais debris que IUC (p<0,05); no médio e cervical, IUP foi mais eficiente que a irrigação convencional, EasyClean reciprocante e IUC (p<0,05). Conclusão: Nenhum método foi capaz de remover completamente os debris. A irrigação ultrassônica passiva foi a que demonstrou melhor efetividade na limpeza dos canais laterais. (AU)

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.

Uso do endoactivator no tratamento endodôntico / Use of the endoactivator in endodontic treatment

Introdução: a irrigação é uma das etapas essenciais no preparo biomecânico e, buscando aumentar a eficiência desta, novos métodos vem sendo empregados no intuito de melhorar a ação e o alcance das soluções irrigadoras. Objetivo: analisar a eficácia do sistema EndoActivator em várias etapas do tratamento endodôntico. Resultados e discussão: apesar de diferenças de metodologias na literatura, o EndoActivator apresentou bons resultados em comparação com a irrigação convencional quando empregado em diferentes fases do tratamento endodôntico. Conclusão: o sistema EndoActivator é seguro e eficaz durante o preparo biomecânico, porém, assim como outros dispositivos de agitação mecânica da solução irrigante, não é capaz de promover completa limpeza dos canais radiculares.

Introduction: the irrigation is an essential part of biomechanical preparation and seeking increase the efficiency of this, new methods have been used in order to expand the effect of irrigating solutions, and promote the reach for areas with difficult access. Objective: the objective of this literature review was to analyze the effectiveness of the EndoActivator system in several stages of endodontic treatment. Results and Discussion: despite differences in methodologies in the literature, the EndoActivator presented good results in comparison to conventional irrigation when used in different phases of endodontic treatment. Conclusion: the EndoActivator system is safe and effective during biomechanical preparation, but, like other mechanical agitation devices of the irrigating solution, it is not able to promote complete cleaning to root canals.