Abstract: This study aimed to describe the morphometric relationship of root canal orifices on the pulp floor in the presence/absence of mesiobuccal second canal (MB2) in the maxillary first molars and other aspects of its internal anatomy. Sixty-two maxillary first molars were scanned by micro-CT. The presence of the MB2 canal was verified. The distance between the center points of the MB1, MB2, distobuccal (DB), and palatal (P) canal orifices on the pulp floor were measured (MB1-MB2, MB1-DB, MB2-DB, MB1-P, and DB-P). The MB1-P to DB-P ratio was calculated. The distances between the anatomic apex and the MB1 and MB2 apical foramina were measured. The length of the band-shaped isthmus was also measured. Student's t-test was applied to verify the association between the presence of an MB2 canal, the interorifice distances, and the ratio of the MB1-P to DB-P distance (α = 5%). The MB2 canal was present in 43 roots (69.35%). Statistics showed significant differences when MB2 was present for the largest MB1-P distance (p < 0.05) and higher values for the MB1-P to DB-P ratio (p < 0.05). A band-shaped isthmus was detected in 25.8% of MB roots. The mean distance from the apical foramen to the isthmus floor ranged from 1.74 for MB1 canals to 1.42 for MB2 canals. Canal orifice distances on the pulp floor may predict the presence of MB2 canals. There was a high incidence of isthmus, accessory canals, and apical delta in the critical apical zone in MB roots of maxillary first molars.

Abstract Objective: To evaluate the sealing capacity and retention of apical barriers made with mineral trioxide aggregate (MTA) and Portland cement (PC). Material and Methods: Fifty-six bovine incisors were sectioned 8 mm above and 12 mm below the cement-enamel junction. The root canal was enlarged with a diamond drill to create a standard 2.5 mm diameter opening. Apical sheets of 5 mm thickness were placed using white MTA-Angelus or white PC. Fifteen samples of each material were exposed to human saliva in a dual chamber apparatus and casting was evaluated at 30 days. Samples without apical barriers and fully sealed samples were used as positive and negative controls (n = 3), respectively. Data were analyzed by Fisher's exact test (p<0.05) after 3 periods: 1 to 10 days (P1); days 11 to 20 (P2); and days 21 to 30 (P3). Then, three 1 mm thick sections were obtained at the apical level of other root samples of each material (n = 10) and the push-out test was performed Results: The leakage rates in P1, P2 and P3 were 60%, 73.3% and 100% for the MTA; and 73.3%, 86.7% and 100% for CP, with no significant difference between materials, regardless of the period analyzed. There were no significant differences between the bond strengths for both cements (p>0.05) Conclusion: Mineral trioxide aggregate and Portland cement apical barriers presented similar sealing ability and bond strength values.

Abstract The aim of the present study was to evaluate the bond strength (BS) of root canal fillings to root dentin using the reciprocating file-matched single-cone or lateral compaction techniques with resin-based and calcium-silicate-based sealers. Maxillary canine roots were prepared and filled using one of the following approaches: Reciproc R40 file and R40 single cone, WaveOne Large file and Large single cone, or ProTaper up to F4 file with lateral compaction. The root filling was performed using AH Plus, Epiphany SE or MTA Fillapex (n = 10). Three 1-mm-thick slices were obtained from each third of each root. Two slices were subjected to a push-out test, and the other slices were prepared for scanning electron microscopy (SEM) to examine the dentin-sealer interface. Data (in MPa) from the push-out tests were analyzed using a two-way ANOVA and Tukey’s test (p < 0.05). Failure modes (adhesive, cohesive or mixed) were evaluated at ×25 magnification. The single-cone techniques resulted in lower BS values than the lateral compaction technique. For lateral compaction, AH Plus and Epiphany SE showed the highest and lowest BS values, respectively. Slight differences were observed between sealers when the single-cone techniques were used. A tendency to reduce the BS toward the apical third was observed. Adhesive failures were predominant for all experimental conditions. A closer adaption of the filling material on the root dentin was observed for the AH Plus and lateral compaction techniques. The Reciproc and WaveOne techniques were associated with lower BS values than the lateral compaction technique. However, the effect of the root canal filling technique appears to be sealer-dependent.

Abstract The aim of this study was to evaluate the influence of drying protocols (DP) on the apical sealing (AS) and on the bond strength (BS) of teeth filled with different sealers. The root canals of one hundred and fifty-six roots of maxillary canines were prepared with Reciproc rotary files (R50). The teeth were randomly divided into four groups (n = 39), according to the DP: GI–paper points; GII–70% isopropyl alcohol + aspiration with NaviTip points; GIII–95% ethanol + paper points; GIV–EndoVac + paper points. Each group was divided into subgroups, according to the sealer used: AH Plus, Sealapex and MTA Fillapex, using a single-cone technique. Evaluation of AS and BS was performed with fluid filtration (FF) and push-out (PO) methods, respectively. The PO test consisted of sectioning the roots, and subjecting a single slice from each third to testing and analysis for failure type. The data was submitted to two-way and three-way variance analysis (ANOVA) and Tukey (α = 5%). The AS showed no drying protocol influence. The FF results revealed a statistically significant difference between MTA and Sealapex (p < 0.05) sealers. The BS test values showed that there was no statistical significant difference among the canal thirds (p > 0.05), but that there was such a difference among the sealers (p < 0.05), among the protocols (p < 0.05), and in the interaction between sealers and protocols (p < 0.05). AH Plus revealed the highest BS values among the sealers; the highest BS results for the sealers occurred with the specimens used with isopropyl alcohol, compared with ethanol and EndoVac.

Abstract This study evaluated the effect of mineral trioxide aggregate (MTA) on the retention of fiber posts in repaired root canal perforations. Ten-millimeter post spaces were prepared in 60 endodontically treated bovine incisors. Root perforations were created in half of the root canals in the cervical area prior to being filled with white MTA-Angelus. Fiber posts were luted into the root canals with two self-adhesive (RelyX Unicem or Set) or self-etching (Panavia F) resin cements. The posts were submitted to a pull-out test, and the data were submitted to two-way ANOVA and Tukey’s post hoc tests (α = 0.05). The fiber posts exhibited reduced retention in MTA-repaired root canal perforations, regardless of the type of resin cement that was used (p < 0.001). Self-adhesive resin cements provided higher bond strength values than Panavia F, while no difference was observed between RelyX Unicem and Set (p > 0.05). The presence of MTA in repaired root perforations negatively affected post retention. In addition, self-adhesive cements seemed to be the best option to lute fiber posts within a root canal in these cases.

Este relato descreve dois casos de remoção de fragmentos de instrumentos de terços apicais de canais radiculares utilizando um extrator personalizado e técnica da agulha modificada, respectivamente. No Caso 1, um extrator foi fabricado para remover fragmento de broca localizado no terço apical do canal radicular de um incisivo central superior. O uso deste extrator permitiu a remoção bem sucedida e conservadora do fragmento de instrumento. No Caso 2, uma agulha para anestesia modificada foi utilizada como um trépano para ganhar acesso ao redor de um fragmento de instrumento localizado na porção apical curva do canal mésio-vestibular de um molar inferior. Um segmento de fio de aço foi inserido no lúmen da agulha para envolver o fragmento metálico, permitindo sua remoção com rotação no sentido anti-horário e simultâneo movimento de retração. Métodos alternativos e criativos são úteis para a remoção intracanal de fragmentos metálicos durante o tratamento endodôntico.

This paper describes two cases of instrument fragment removal from the apical thirds of root canals using a customized extractor and a modified needle technique, respectively. In case 1, a customized extractor was manufactured to remove a bur fragment located in the apical root canal of a maxillary central incisor. The use of this extractor enabled successful and conservative removal of the instrument fragment. In case 2, a modified injection needle was used as a trepan to gain access around an instrument fragment located in the curved apical portion of the mesiobuccal canal of a mandibular molar. A segment of steel wire was inserted into the needle lumen to engage the metallic fragment, enabling its removal with counter-clockwise rotation and a simultaneous pull-out motion. Alternative and creative methods are useful for the management of intracanal metallic fragments during root canal treatment.

Este relato de caso descreve a obturação do canal radicular realizada sobre um grande fragmento da lima ProTaper S1 em um segundo molar inferior com pulpite irreversível. Uma lima ProTaper S1 fraturou durante a instrumentação do canal mésio-vestibular. Aproximadamente 10 mm de remanescente do fragmento da lima permaneceu nos terços apical e médio do canal. A obturação foi realizada sobre este fragmento usando guta-percha compactada termomecanicamente e cimento endodôntico. Achados radiográficos e ausência de sinais e sintomas clínicos após 3 anos de acompanhamento indicaram o sucesso do tratamento. Imagens de tomografia computadorizada de feixes cônicos revelaram a ausência de lesão periapical e detalhes do fragmento da lima intracanal relacionados à obturação do canal radicular e à morfologia do ápice. Neste caso, a presença de grande instrumento fraturado intracanal não teve impacto negativo no prognóstico endodôntico durante o período de acompanhamento.

This case report describes root canal filling performed over a large S1 ProTaper file fragment in a second mandibular molar with irreversible pulpitis. An S1 ProTaper file was fractured during the instrumentation of the mesiobuccal canal. Approximately 10 mm of file fragment remained in the apical and middle thirds of the canal. The obturation was performed over this fragment using thermomechanically compacted gutta-percha and sealer. Radiographic findings and the absence of clinical signs and symptoms at 3-year follow up indicated successful treatment. Cone-beam computed tomography images revealed absence of periapical lesion and details of intracanal file fragment related to root fillings and apex morphology. In this case, the presence of a large intracanal fractured instrument did not have a negative impact on the endodontic prognosis during the follow up evaluation period.

Objective: This study evaluated apical transportation associated with ProTaper® Universal Fl, F2 and F3 rotary files in curved canais prepared by undergraduate students. Material and Methods: Twenty mesial roots of mandibular molars with curvatures ranging between 25° and 35° were selected. Mesiobuccal canals were instrumented by twenty students with the ProTaper® system (Dentsply-Maillefer, Ballaigues, Switzerland) according to the manufacturer's instructions. Pre-fiaring was performed with Sl and SX files. A #15 K-file was inserted into the root canal up to the working length (WL), and an initial digital radiograph was taken in a buccolingual direction (baseline). Afterwards, the S1, S2, F1, F2, and F3 files were employed up to the WL. Other radiographies were taken in the same orientation of the baseline after the use of the Fl, F2, and F3 files, with each file inserted into the root canal. The radiographic images were overlapped, and the Image J software was used to measure the distance between the rotary files' ends and the #15 K-file's end, characterizing the apical transportation. Data were analyzed by Repeated Measure ANOVA and by the SNK post hoc test (P<0.05). Results: It was verified that file size affected apical transportation significantly (P<0.001). The F3 file showed higher apical transportation than Fl and F2, while between these last files there was no difference. Conclusion: The undergraduate students produced lower apical transportation in curved canals when they did not use the F3 rotary file.

OBJECTIVE: This ex vivo study evaluated the effect of pre-flaring and file size on the accuracy of the Root ZX and Novapex electronic apex locators (EALs). MATERIAL AND METHODS: The actual working length (WL) was set 1 mm short of the apical foramen in the palatal root canals of 24 extracted maxillary molars. The teeth were embedded in an alginate mold, and two examiners performed the electronic measurements using #10, #15, and #20 K-files. The files were inserted into the root canals until the "0.0" or "APEX" signals were observed on the LED or display screens for the Novapex and Root ZX, respectively, retracting to the 1.0 mark. The measurements were repeated after the preflaring using the S1 and SX Pro-Taper instruments. Two measurements were performed for each condition and the means were used. Intra-class correlation coefficients (ICCs) were calculated to verify the intra- and inter-examiner agreement. The mean differences between the WL and electronic length values were analyzed by the three-way ANOVA test (p<0.05). RESULTS: ICCs were high (>0.8) and the results demonstrated a similar accuracy for both EALs (p>0.05). Statistically significant accurate measurements were verified in the pre-flared canals, except for the Novapex using a #20 K-file. CONCLUSIONS: The tested EALs showed acceptable accuracy, whereas the pre-flaring procedure revealed a more significant effect than the used file size.

Este estudo avaliou a atividade antibacteriana do extrato de Rosmarinus officinalis e do potencial deste extrato vegetal para a desinfecção de cones de guta-percha (GP). No primeiro experimento, o extrato hidroalcoólico de Rosmarinus officinalis (folhas), em diluição de 10% m/v, foi testado contra Enterococcus faecalis, utilizando o método de discodifusão em ágar. Os controles positivos e negativos foram o álcool de cereais 70% e antibióticos, respectivamente. Os procedimentos foram realizados em triplicata e os diâmetros de halos de inibição foram mensurados com um paquímetro, após 24 horas a 37 º C. No segundo experimento, os procedimentos de desinfecção foram avaliados em cones de GP artificialmente contaminados com Enterococcus faecalis. O extrato de R. officinalis foi comparado com o gluconato de clorexidina a 2% e com hipoclorito de sódio a 2,5% através de um teste de exposição direta por 5 minutos. Cones esterili - zados e cones não desinfectados foram utilizados como controles negativo e positivo, respectivamente. Após 24h de incubação, as contagens bacterianas foram enumeradas. Em ambos os experimentos, os dados foram analisados estatisticamente pelos testes de Kruskall-Wallis e Tukey (p <0,05). O extrato vegetal apresentou halos de inibição semelhantes aos antibióticos testados. Expessiva descontaminação dos cones foi verificada com todas as soluções desinfetantes, sem dife - renças significativas entre elas. O extrato de R. officinalis mostrou efeito bactericida sobre Enterococcus faecalis e capacidade de desinfetar cones de GP contaminados com este microrganismo.

This study evaluated the antibacterial activity of Rosmarinus officinalis extract and its potential for disinfecting guttapercha (GP) cones. In the first experiment, a hydro-alcoholic extract of Rosmarinus officinalis (leaves) in a dilution ratio of 10% m/v was tested against Enterococcus faecalis by using the disk diffusion method. Positive and negative controls were 70% cereal alcohol and antibiotics, respectively. The procedures were performed in triplicate, and the diameters of the zones of growth inhibition were measured with a caliper after 24 h at 37ºC. In the second experiment, the disinfection procedures were evaluated on GP cones artificially contaminated with Enterococcus faecalis. The R. officinalis extract was compared with 2% chlorhexidine digluconate and 2.5% sodium hypochlorite, using a direct exposure test (5 min treatment). Sterilized and non-disinfected cones were used as negative and positive controls, respectively. After 24 h of incubation, bacterial counts were taken. For both experiments, the data were statistically analyzed by Kruskall-Wallis and Tukey's tests (p<0.05). The plant extract produced zones of inhibition comparable to those of tested antibiotics. Significant GP cone disinfection was verified with all disinfectant solutions, with no significant difference between them. R. officinalis extract showed bactericidal effect on Enterococcus faecalis and capacity to disinfect GP cones contamined with it.

Este estudo in vitro comparou diferentes modos de vibração ultra-sônica na remoção de pinos intra-radiculares fundidos. As coroas de 24 caninos superiores foram removidas, as raízes foram incluídas em blocos de resina acrílica e tratadas endodonticamente. Os espaços para os pinos intra-radiculares foram preparados e depois moldados com resina acrílica autopolimerizável. Após a fundição, os pinos intra-radiculares foram cimentados com cimento de fosfato de zinco. As amostras foram distribuídas aleatoriamente em três grupos (n=8): G1: sem vibração ultra-sônica (controle), G2: ponta do aparelho ultra-sônico posicionada perpendicularmente à superfície do núcleo e perto da borda incisal e G3: ponta do aparelho ultra-sônico posicionada perpendicularmente à superfície do núcleo na região cervical, perto da linha de cimentação. Uma unidade de ultra-som Enac OE-5 com uma ponta ST-09 foi usada. Todas as amostras foram submetidas ao teste de tração utilizando máquina universal de ensaios a uma velocidade de 1 mm/min. Os dados foram submetidos aos testes ANOVA e Tukey post-hoc (α = 0,05). Os valores médios de carga para deslocar os pinos (MPa) foram: G1 = 4,6 (± 1,4) A; G2 = 2,8 (± 0,9), B e G3 = 0,9 (± 0,3) C. Portanto, a vibração ultra-sônica aplicada com a ponta do dispositivo perto da zona cervical do núcleo apresentou maior capacidade de reduzir a retenção de pinos metálicos fundidos no canal radicular

This in vitro study compared different ultrasonic vibration modes for intraradicular cast post removal. The crowns of 24 maxillary canines were removed, the roots were embedded in acrylic resin blocks, and the canals were treated endodontically. The post holes were prepared and root canal impressions were taken with self-cured resin acrylic. After casting, the posts were cemented with zinc phosphate cement. The samples were randomly distributed into 3 groups (n=8): G1: no ultrasonic vibration (control); G2: tip of the ultrasonic device positioned perpendicularly to core surface and close to the incisal edge; and G3: tip of the ultrasonic device positioned perpendicularly to core surface at cervical region, close to the line of cementation. An Enac OE-5 ultrasound unit with an ST-09 tip was used. All samples were submitted to the tensile test using an universal testing machine at a crosshead speed of 1 mm/min. Data were subjected to one-way ANOVA and Tukey's post-hoc tests (α=0.05). Mean values of the load to dislodge the posts (MPa) were: G1 = 4.6 (± 1.4) A; G2 = 2.8 (± 0.9) B, and G3= 0.9 (± 0.3) C. Therefore, the ultrasonic vibration applied with the tip of device close to the core's cervical area showed higher ability to reduce the retention of cast post to root canal.

Este estudo avaliou a capacidade de selamento do MTA-Angelus cinza manipulado com propilenoglicol em perfuracoes de furca usando um teste de infiltracao bacteriana. Perfuracoes de furca foram criadas em 30 molares inferiores usando uma broca esferica numero 3. As amostras foram divididas aleatoriamente em dois grupos experimentais (n=10) de acordo com o agente de manipulacao. Em G1, o po do MTA foi manipulado com propilenoglicol enquanto que a agua destilado foi utilizada no G2. A proporcao po-liquido de 3:1 foi usada para ambos os grupos. O MTA foi colocado na perfuracao com uma porta- MTA e condensado com condensadores manuais. Perfuracoes nao-reparadas (n=5) e totalmente impermeabilizadas (n=5) serviram como controle positivo e negativo, respectivamente. A infiltracao bacteriana foi verificada diariamente durante 30 dias em um aparato de dupla camara com Enterococcus faecalis. Os dados foram analisados pelo teste exato de Fisher (p<0,05) para tres periodos: 1o ao 10o dia (P1), 11o ao 20o dia (P2) e do 21o ao 30o dia (P3). O controle positivo apresentou infiltracao em todas as amostras nas primeiras 24 horas, enquanto nenhuma infiltracao foi observada no controle positivo durante o periodo experimental. Infiltracao foi observada em 5 (50%) das 10 amostras do grupo do propilenoglicol (G1) e 7 (70%) do grupo da agua destilada no 20o dia, sem diferenca significativa entre o grupos nos periodos P1 e P2 (p=0,0137). A infiltracao foi significantemente menor para G1 que para G2 no periodo P3 (50% versus 100%, respectivamente, p=0,016). Neste metodo de infiltracao de apenas uma bacteria aerobica, o uso do propilenoglicol como veiculo para o MTA-Angelus cinza aumentou sua capacidade de selamento em perfuracoes de furca no final do periodo experimental de 30 dias.

This study evaluated the sealing ability of gray MTA-Angelus mixed with propyleneglycol in furcal perforations using a bacterial leakage test. Furcal perforations were created in 30 human mandibular molars using a size 3 round bur. The samples were divided randomly into 2 experimental groups (n=10) according to the mixing agent. In G1, the MTA powder was mixed with propyleneglycol, while distilled water was used in G2. A 3:1 powder-liquid ratio was used for both groups. The MTA was placed in the perforation with an MTA carrier and condensed with hand pluggers. Nonrepaired (n=5) and totally sealed (n=5) perforations served as positive and negative controls, respectively. Bacterial leakage was assessed daily for 30 days in a double-chamber apparatus with Enterococcus faecalis. Data were analyzed using Fisher exact test (p<0.05) for three leakage periods: 1st to 10th day (P1); 11th to 20th day (P2); and 21st to 30th day (P3). The positive control presented leakage in all specimens within the first 24 hours, while no leakage was observed in the negative control during the experimental period. Leakage was observed in five (50%) of the 10 samples of the propyleneglycol group (G1) and seven (70%) of the distilled water group (G2) by the 20th day, without significant difference between the groups in periods P1 and P2 (p=0.137). The leakage was significantly lower for G1 than G2 in period P3 (50% versus 100%, respectively, p=0.016). In this single aerobic bacterial leakage method, the use of propyleneglycol as a vehicle for gray MTAAngelus increased its sealing ability in furcal perforations at the end of the 30-day experimental period.

O objetivo deste estudo foi avaliar o padrão de qualidade de 1.347 obturações de canais radiculares realizadas por estudantes de pós-graduação em endodontia, conforme 3 parâmetros radiográficos. Os parâmetros de qualidade analisados incluíram limite apical (LA), conicidade (CO) e homogeneidade (HO), os quais receberam escores E2 (padrão ideal), E1 (suave desvio) ou E0 (desvio acentuado). Obturação perfeita (OP) recebeu E2 em todos os parâmetros. Na ausência de um ou dois E2, as obturações foram consideradas satisfatórias (OS) ou deficientes (OD), respectivamente. Os resultados mostraram 51,7%, 41,5% e 6,8% de OP, OS e OD, respectivamente. LA, CO e HO apresentaram semelhantes parâmetros de qualidade nos canais radiculares de incisivos e pré-molares inferiores (p>0,05). Em contrapartida, nas obturações de incisivos superiores, caninos e canais distais de molares inferiores, foram encontradas diferenças significativas entre 2 parâmetros (p<0,05). Além disso, houve diferença significativa (p<0,05) entre os parâmetros medidos em obturações de canais radiculares de pré-molares superiores, todos os canais radiculares de molares superiores e canais mesiais de molares inferiores. LA mostrou a menor frequência de E2 para todos os grupos. Em conclusão, a prevalência de obturações perfeitas, satisfatórias e deficientes variou significativamente em função dos grupos de canais radiculares. Os parâmetros de qualidade categorizaram as obturações em 3 graus de complexidade. LA foi o parâmetro crítico da qualidade das obturações dos canais radiculares.

The aim of this study was to evaluate the standard quality of 1,347 root fillings performed by postgraduate students in Endodontics according to 3 radiographic quality parameters. The analyzed quality parameters included apical extension (AE), taper (TA) and homogeneity (HO), which received scores S2 (ideal standard), S1 (slight deviation) or S0 (accentuated deviation). A perfect filling (PF) received S2 for all parameters. In the absence of one or two S2 score, the fillings were deemed as satisfactory (SF) or deficient (DF), respectively. The results showed 51.7%, 41.5% and 6.8% of PF, SF, and DF, respectively. AE, TA, and HO presented equivalent quality parameters in root-filled canals of mandibular incisors and mandibular premolars (p>0.05). Conversely, in maxillary incisors, canines and distal root of mandibular molars, significant differences (p<0.05) were found between 2 parameters. Besides, there were significant differences (p<0.05) among the measured parameters in root-filled canals of maxillary premolars, all root canals of the maxillary molars and mesial root of the mandibular molars. AE showed the lowest frequency of S2 score for all groups. In conclusion the prevalence of perfect, satisfactory and deficient fillings varied significantly according to the root canal group. The quality parameters categorized fillings in 3 complexity degrees. AE was the most critical parameter of quality in root canal fillings.

O objetivo deste estudo foi comparar a capacidade de selamento do agregado trioxido mineral (MTA) branco com outros materiais usados como barreiras cervicais durante clareamento intra-coronario. Trinta e oito dentes extraidos foram endodonticamente tratados e 3 mm de obturacao foi removida para receber o material da barreira: G1- Coltosol; G2 - Vidrion R; G3 - MTA branco; G4-Nenhuma barreira (controle negativo) e G5- Raizes totalmente protegidas com tres camadas de cianocrilato (controle positivo). Peroxido de hidrogenio a 30% (PH) associado com perborato de sodio foi deixado na camara pulpar por 24 h. As amostras foram imersas em tubos de ensaio contendo uma solucao de cromato de potassio (amarela) que se torna azul na presenca de peroxido de hidrogenio. Dois avaliadores calibrados atribuiram escores de acordo com a cor obtida na solucao detectora (0 - cor inalterada, 1 - azul claro e 2 - azul escuro). Os dados foram analisados pelo teste de Kruskall-Wallis (p<0,05). Os resultados nao mostraram diferencas estatisticamente significantes entre o grupo experimental G3 e o controle positivo (G5). Nenhuma diferenca estatisticamente significante foi observada entre G1 e G3. Entretanto, diferenca estatistica foi verificada entre G2 e G3. MTA apresentou maior habilidade de selamento que o Vidrion R e nao diferiu do controle positivo. Entretanto, nao houve diferenca entre MTA e Cotosol.

The aim of this study was to compare the sealing ability of white mineral trioxide aggregate (MTA) with that of other materials used as a cervical barrier during intracoronal bleaching. Thirty eight extracted teeth were endodontically treated and 3 mm of filling was removed to receive the barrier material: G1- Coltosol; G2 - Vidrion R; G3 - White MTA; G4-No barrier (negative control) and G5- Roots totally protected with three layers of cyanoacrylate (positive control). The 30% hydrogen peroxide associated with the sodium perborate was left in the pulp chamber for 24 h. The specimens were immersed in a test tube containing a solution of potassium chromate (yellow), which turns blue in the presence of hydrogen peroxide. Two calibrated evaluators scored according to color in the presence of the detecting solution (0 - unaltered color, 1 - light blue and 2 - dark blue). Data were analyzed by the Kruskall-Wallis test (p<0.05). The results showed no statistically significant differences between the experimental group G3 and positive control (G5). No statistically significant difference was observed between G1 and G3. However, a statistical difference was verified between G2 and G3. MTA presented higher sealing ability than Vidrion R and did not differ from the positive control. However, there was no difference between MTA and Coltosol.

OBJECTIVE: This in vitro study evaluated the influence of luting agents on ultrasonic vibration time for intraradicular cast post removal. MATERIAL AND METHODS: After endodontic treatment, 30 roots of extracted human canines were embedded in resin cylinders. The post-holes were prepared at 10 mm depth and their impressions were taken using autopolymerizing acrylic resin. After casting procedures using a nickel-chromium alloy, the posts were randomly distributed into 3 groups (n=10) according to the luting material: G1- zinc phosphate (SS White) (control group), G2 - glass ionomer cement (Vidrion C; SS White), and G3- resin cement (C&B; Bisco). In G3, the adhesive procedure was performed before post cementation. After 24 h, the cement line was removed at the post/tooth interface using a fine diamond bur, and the ST-09 tip of an Enac ultrasound unit was applied at maximum power on all surfaces surrounding the posts. The application time was recorded with a chronometer until the post was completely dislodged and data were analyzed by ANOVA and Tukey's test (p<0.05). RESULTS: The roots were removed from the acrylic resin and inspected to detect cracks and/or fractures. The means for G1, G2, and G3 were 168.5, 59.5, and 285 s, respectively, with statistically significant differences among them. Two G3 posts resisted removal, one of which developed a vertical fracture line. CONCLUSIONS: Therefore, the cement type had a direct influence on the time required for ultrasonic post removal. Compared to the zinc phosphate and glass ionomer cements, the resin cement required a longer ultrasonic vibration time.