Optimization of automated preparation of long oval-shaped root canals using supplementary instrumentation

Abstract This study compared the preparation of long oval-shaped root canals using WaveOne Gold and XP-endo Shaper systems, both supplemented or not with manual instrumentation. Twenty-four long oval-shaped canals of mandibular incisors were distributed into two groups according to the instrumentation: WaveOne Gold Primary or XP-endo Shaper systems. All root canals were manually instrumented with a size 25 K-file after automated preparation. The specimens were scanned by using a micro-CT device (17.42 µm) before and after automated preparation and manual instrumentation. The increased surface of the root canal and the percentage of untouched areas were assessed. Both WaveOne Gold and XP-endo Shaper systems increased the root canal surface and had similar untouched areas (p>0.05). Supplementary instrumentation increased the surface of the root canal and decreased the untouched walls (p<0.05). WaveOne Gold and XP-endo Shaper systems provided a similar preparation of long oval-shaped canals and manual instrumentation improved their preparation.

Resumo Este estudo comparou o preparo de canais radiculares ovais longos usando os sistemas WaveOne Gold e XP-endo Shaper, ambos complementados ou não com instrumentação manual. Vinte e quatro canais longos e ovais de incisivos inferiores foram distribuídos em dois grupos de acordo com a instrumentação: sistemas WaveOne Gold Primary ou XP-endo Shaper. Todos os canais foram instrumentados manualmente com uma lima K tamanho 25 após preparo automatizado. Os espécimes foram escaneados usando um dispositivo de micro-CT (17,42 µm) antes e após o preparo automatizado e instrumentação manual. O aumento de superfície do canal radicular e a porcentagem de áreas intocadas foram avaliadas. Ambos os sistemas WaveOne Gold e XP-endo Shaper aumentaram a superfície do canal radicular e apresentaram áreas intocadas semelhantes (p>0,05). A instrumentação complementar aumentou a superfície do canal radicular e diminuiu o percentual de áreas intocadas (p <0,05). Os sistemas WaveOne Gold e XP-endo Shaper tiveram o preparo de canais ovais longos semelhantes, e a instrumentação manual melhorou o preparo.

Assessment of the Performance and Surface Alteration of Two Single-file Systems According to the Number of Uses

Abstract The aim of this study was to assess the performance and surface alteration of two single-file systems according to the number of uses. Ten WaveOne Primary files (25/.08) and ten One Shape NG files (25/.06) were used for instrumentation of mesial root canals of mandibular molars. Each instrument was cleaned and sterilized after the preparation of two root canals and then reused. The time spent for instrumentation of each root canal was recorded and analyzed by using t-test. Microphotographs of the surface of the instruments were taken with a scanning electron microscope at different magnifications (i.e. 18x, 160x, 500x and 1000x) and at a distance of 4 mm from the instrument's tip before being analyzed by four observers. Presence of disruption of cutting edge, crack, craters and unwinding was assessed and submitted to Fisher's exact test. Both systems showed manufacturing defects and cracks. The presence of disruption of cutting edges was major in WaveOne files from the sixth use, whereas One Shape NG files showed more unwinding. Only preparation time using WaveOne files was influenced by the number of uses. One can conclude that WaveOne files had more disruption of cutting edges and took longer time for root canal preparation from the sixth use onwards, whereas the One Shape NG files showed more unwinding at the tenth use.

Evaluation of the waveone gold and one shape new generation in reducing enterococcus faecalis from root canal

Abstract The aim of this study was to evaluate the WaveOne Gold and One Shape New Generation systems regarding the bacterial removal from root canals infected with Enterococcus faecalis by comparing them to the conventional WaveOne and One Shape systems. Forty-eight distobuccal root canals of maxillary molars sterilized with ethylene oxide were infected with E. faecalis for 21 days, and then root canal initial bacterial sample was collected with paper cones and plated on M-enterococcus agar. The specimens were randomly divided into 4 groups according to the instrumentation: WaveOne Gold, One Shape New Generation, WaveOne and One Shape. After instrumentation, samples were collected with use of scraping and paper cones at immediate and 7 days after instrumentation. The bacterial reduction was calculated and then made intragroup analysis by Friedman test and intergroup analysis by Kruskal-Wallis with Dunn's post-hoc test, all at 5% significance. All techniques significantly reduced the number of bacteria in the root canal (p<0.05). WaveOne Gold and One Shape New Generation promoted higher bacterial reduction than WaveOne and One Shape systems (p<0.05), but no significant difference was found between WaveOne Gold and One Shape New Generation or between WaveOne and One Shape (p>0.05). Novel single-file systems promote better bacterial removal than the conventional single-file systems.

Resumo A proposta deste estudo foi avaliar os sistemas WaveOne Gold e One Shape New Generation em relação à remoção bacteriana de canais infectados com Enterococcus faecalis, comparando-os com seus sistemas convencionais WaveOne e One Shape. Quarenta e oito canais disto vestibulares de molares superiores esterilizados em óxido de etileno foram contaminados com E. faecalis por 21 dias, e então acoleta bacteriana inicial foi feita com cone de papel e plaqueadas em M-enterococcus agar. Os espécimes foram aleatoriamente divididos em quarto grupos de acordo com a instrumentação: WaveOne Gold, One Shape New Generation, WaveOne e One Shape. Após instrumentação, amostras foram coletadas utilizando limagem e cones de papel imediatamente e 7 dias após o preparo. A redução bacteriana foi calculada e então feita análise intra grupos com teste de Friedman, e entre grupos utilizando Kruskal-Wallis e teste de Dunn, todos a 5% de significância. Todas as técnicas reduziram significantemente o número de bactérias do canal radicular (p<0.05). WaveOne Gold e One Shape New Generation promoveram maior redução bacteriana que WaveOne e One Shape (p<0.05), mas nenhuma diferença significante foi encontrada entre WaveOne Gold e One Shape New Generation ou entre WaveOne e One Shape (p>0.05). Novos sistemas de lima-única promovem melhor remoção bacteriana que seus sistemas convencionais.

Immunohistological study of the effect of vascular Endothelial Growth Factor on the angiogenesis of mature root canals in rat molars

Abstract Tissue bioengineering has been applied to Endodontics to seek a more biological treatment. The presence of blood vessels is crucial for cell nutrition during tissue formation. Objective This study analysed the application of vascular endothelial growth factor (VEGF) in the angiogenesis of mature root canals. Material and methods Upper first molars of twelve 13-week old Wistar male rats were used. The root pulp of the mesiobuccal canal was removed and the root canal instrumented with K-files up to size #25. Periapical bleeding was induced into the root canal by introducing a #15 K-file beyond the apex. The teeth on the right side of the arch were filled up with blood clot (G1), whereas those on the left side were filled up with blood clot plus 50 ng/ml of VEGF (G2). Teeth were sealed with light-curing glass-ionomer cement and the animals were sacrificed after 60 days. The maxilla was dissected and fixed before obtaining serial sections for histological processing with haematoxylin-eosin (HE) and immunohistochemical factor-VIII. Immunohistochemical labelling was evaluated using scores for statistical analysis. Results Immunohistological analysis demonstrated the presence of angiogenesis in both groups, but with higher angiogenic maturation in G2 during the experimental period (p<0.05). HE staining showed connective tissue with absence of odontoblasts in all specimens. Conclusions It can be concluded that it is possible to obtain angiogenesis in mature root canals with or without the use of VEGF, although the latter tends to accelerate blood vessel formation.

Instrument Design May Influence Bacterial Reduction During Root Canal Preparation

Abstract The aim of this study was to evaluate the bacterial reduction promoted by ProTaper Next and Twisted File by comparing to ProTaper Universal and manual technique. Sixty distobuccal root canals of maxillary molars sterilized with ethylene oxide were contaminated with Enterococcus faecalis broth culture. After incubation for 21 days, bacterial samples were collected and cultured on m-Enterococcus agar plates. The root canals were divided into 4 groups, according to the system used for instrumentation: ProTaper Next, Twisted File, ProTaper Universal, and crown down manual technique. Other 8 uncontaminated root canals were control asepsis. Bacterial samples were collected immediately and 7 days after instrumentation. The bacterial reduction was calculated and then made intragroup analysis by paired t-test and intergroup analysis by ANOVA and Tukey tests, all at 5% significance. All techniques significantly reduced the bacterial number in the root canal (p<0.05). ProTaper Next and Twisted File resulted in more bacterial reduction than ProTaper Universal and manual technique (p<0.05). ProTaper Next and Twisted File were similar (p>0.05). It can be concluded that ProTaper Next and Twisted File promote a higher bacterial reduction than Protaper Universal and manual technique.

Resumo A proposta deste estudo foi avaliar a redução bacteriana promovida pelos sistemas ProTaper Next e Twisted File comparando-os ao sistema ProTaper Universal e técnica manual. Sessenta raízes disto vestibulares de molares superiores esterilizadas com óxido de etileno foram contaminadas com Enterococcus faecalis. Após incubação por 21 dias, amostras foram coletas e cultivadas em m-Enterococcus agar. Os canais foram divididos em 4 grupos de acordo com o sistema de instrumentação: ProTaper Next, Twisted File, ProTaper Universal, e técnica manual crown-down. Outros 8 canais não contaminados foram utilizados como controle de assepsia. Amostra bacteriana foi coletada imediatamente após o prepare e aos 7 dias. A redução bacteriana foi calculada, e então feita a análise intergrupos utilizando teste t-pareado, e análise entre grupos utilizando os testes ANOVA e Tukey, todos com 5% de significância. Todas as técnicas reduziram significantemente o número de bactérias no canal radicular (p<0.05). ProTaper Next e Twisted File resultaram em maior redução bacteriana que ProTaper Universal e técnica manual (p<0.05). ProTaper Next e Twisted File foram semelhantes (p>0.05). Pode-se concluir que ProTaper Next e Twisted File promovem maior redução bacteriana que Protaper Universal e técnica manual.

Análise de diagnósticos radiográfico periapicais sugestivos de lesões refratárias / Analysis of periapical radiographic diagnosis that suggest persistent lesion

Cicatrizes fibrosas periapicais podem ter aspecto radiográfico semelhante a lesões periapicais, levando ao plano de tratamento incorreto. Assim, o objetivo deste estudo foi realizar um confronto entre o diagnóstico radiográfico e histopatológico de dentes que foram tratados endodonticamente e apresentaram“lesões periapicais” detectadas radiograficamente após 18 meses do tratamento. Dez pacientes submetidos ao tratamento endodôntico adequado e apresentando imagem radiolúcia persistente 18 meses pós-tratamento, tiveram cirurgia paraendodôntica indicada. Durante a cirurgia, o tecido em volta do ápice foi removido e mergulhado em solução de formalina 10% para processamento histopatológico através de coloração de HE. O ápice removido na apicectomia foi mantido em glutaraldeído 2% e processado para análise por microscopia eletrônica de varredura. Dentre os 10 casos sugestivos de lesão periapical, em apenas um caso foi confirmado diagnóstico de cisto, um caso de granuloma, e os outros oito casos confirmaram cicatriz fibrosa. Em nenhum dos casos foi detectada a presença de bactéria extrarradicular, somente infiltrado inflamatório e presença de células de defesa como linfócitos e neutrófilos, além de hemácias, tecido conjuntivo e colágeno. Pode-se concluir que a radiográfica convencional não constitui ponto conclusivo no diagnóstico de lesões periapicais.

Periapical fibrous scars may have similar radiographic appearance of periapical lesions that canresult in incorrect diagnosis. The aim of this study was a confrontation between the radiographic and histopathologic diagnosis of teeth that were endodontically treated and presented “persistent periapical lesions” detected radiographically after 18 months of treatment. Ten patients under going adequate endodontic treatment and presenting persistent radiolucent image at 18 months post-treatment, had surgery Para endodontic indicated. During surgery, the tissue around the apex was removed and immersedin 10% formalin solution for histological processing by HE staining. The apex oh the tooth was removed and immersed in 2% glutaral dehyde for scanning electron microscopy processing. Among the 10 radiographically suggestive cases of persistent periapical lesion, only 1 case was confirmed diagnosis of cyst, 1 case of granuloma, and the other 8 cases were fibrous scar. In neither case was observed the presence of bacteria, only inflammatory infiltrate and the presence of defense cells such as lymphocytes and neutrophils, red blood cells, connective tissue and collagen. It can be concluded that the conventional radiography is not conclusive point in the diagnosis of periapical lesions.

Comparação do teor de cloro ativo e pH do hipoclorito de sódio 0, 5% fabricado e manipulado / Comparison of active chlorine and pH of manufactured and manipulated sodium hypochlorite 0.5%

O objetivo deste estudo foi verificar a real concentração de cloro ativo e pH do hipoclorito de sódio a 0,5% fabricado e manipulado. Foram analisadas 10 amostras de hipoclorito de sódio 0,5%, sendo 5 adquiridas em comércio e outros 5 em farmácias de manipulação. As amostras foram armazenadas em frascos de vidro âmbar e mantidas em caixa de isopor. Assim, foi realizada a medição de pH com um pHmetro, e o cloro ativo por titulometria. Os dados foram submetidos ao teste de Mann-Whitney (p=0.05). A medição de pH variou de 7.7 a 11.5, com média de 9.45, e em relação à concentração de cloro ativo houve uma variação de 0,04% a 0,45%. A análise estatística não apresentou diferença significante entre os grupos. Pode-se concluir que hipoclorito de sódio 0,5% manipulado e vendido comercialmente não se diferiu entre si em relação à sua concentração, no entanto, há falta de controle entre alguns fabricantes/manipuladores quanto à real concentração de cloro ativo. Maior parte dos produtos comercializados possui pH dentro do proposto na literatura...

The aim of this study was to verify the actual concentration of active chlorine and pH of manufactured and manipulated sodium hypochlorite 0.5%. Ten samples of the sodium hypochlorite 0.5% were analyzed, 5 manufactured and other 5 manipulated. The samples were stored in amber glass bottles and styrofoam box. Then, it was performed the pH measurement using a pHmeter, and the active chlorine by titrimetry. The data were submitted to Mann-Whitney test (p=0.05). PH measuring ranged from 7.7 to 11.5, with a mean of 9.45, and active chlorine concentration ranged from 0.04% to 0.45%. There was no significant difference between the groups. It can be concluded that manufactured and manipulated sodium hypochlorite 0.5% did not differ regarding concentration, and there is no control of concentration for both manufacturer and manipulator. Most of manufactured and manipulated products presented pH in accordance to that proposed in the literature...

Análise do efeito do fator de crescimento endotelial na angiogênese em canais de dentes de ratos com apicigênese completa / Analysis of the effect of vascular endothelial growth factor on angiogenesis of root canal in mature teeth of rats

A bioengenharia tecidual tem sido aplicada na Endodontia na busca de tratamentos mais biológicos. A revascularização pulpar tem sido observada em dentes com ápice aberto, porém há poucos estudos direcionados aos dentes com ápice formado. A angiogênese é primordial para a nutrição celular durante a regeneração tecidual. O objetivo deste estudo foi analisar o efeito do fator de crescimento endotelial (VEGF) na angiogênese após pulpectomia de canais radiculares de rato com apicigênese completa. A câmara pulpar dos primeiros molares superiores de 12 ratos machos Wistar com 13 semanas foi acessada. A polpa radicular do canal mésio vestibular foi removida e o canal instrumentado até a lima K25. Com uma lima K20, além do limite foraminal, foi induzido o sangramento periapical para o canal radicular. Os dentes do lado direito da arcada foram preenchidos com coágulo sanguíneo (GS), e nos dentes do lado esquerdo foi utilizado VEGF165 recombinante (Prospec, Israel) adicionado ao coágulo (GV). Os dentes foram selados com ionômero de vidro fotopolimerizável, e 60 dias depois os animais foram sacrificados. A maxila foi dissecada, fixada, descalcificada e incluída em parafina. Cortes transversais seriados foram feitos e corados com hematoxilina-eosina para avaliação morfológica ou incubados com anticorpo de coelho anti-fator VIII (Bioss, EUA) para análise da angiogênese. A análise histológica demonstrou canais preenchidos por tecido conjuntivo sem presença de odontoblastos nos dois grupos. A imuno-histoquímica demonstrou positividade para o anticorpo no tecido neoformado em ambos os grupos. No grupo 1 foi predominante a marcação difusa, e no grupo 2 foi a marcação definida. Pode-se concluir que o uso de VEGF acelera a angiogênese que ocorre em canais pulpectomizados de molares com apicigênese completa.

The tissue engineering has been applied in Endodontics in search of more biological treatments. The pulp revascularization has been observed in immature teeth, but there are few studies directed to the closed-apex teeth. Angiogenesis is essential for cellular nutrition during tissue regeneration. The aim of this study was to analyze the effect of vascular endothelial growth factor (VEGF) in angiogenesis after pulp removal in rats with mature teeth. The pulp chamber of upper first molars of 12 male Wistar rats with 13-weeks-old was accessed. The pulp of the mesiobuccal root canal was removed, and the root canal was shaped up to 25K-file. Then, a 20K-file was introduced beyond the apex to induce bleeding. The teeth on the right side of the arch are filled using blood clot alone (GS) and the teeth on the left side was filled using blood clot + VEGF165 recombinant (Prospec, Israel) (GV). The teeth were coronally sealed using light-curing glass ionomer, and the animals were sacrificed after 60 days. The samples were dissected, fixed, decalcified and included in paraffin. Transverse serial sections were made, and stained using hematoxylin-eosin to morphological evaluation or expressed by immunostaining using anti-Factor VIII rabbit antibody (BIOSs, USA) to angiogenesis analysis. Morphological analysis showed root canals filled by connective tissue without the presence of odontoblasts in both groups. Immunohistochemistry showed positivity for the antibody in the new tissue in both groups, with marking defined in group 2. Diffuse marking was predominant in the group 1, and the well-maked type was predominant in the group 2. It can be concluded that the use of VEGF accelerates angiogenesis that occurs in root canal of closed-apex molars after pulpectomy.

Análise do efeito do fator de crescimento endotelial na angiogênese em canais de dentes de ratos com apicigênese completa / Analysis of the effect of vascular endothelial growth factor on angiogenesis of root canal in mature teeth of rats

A bioengenharia tecidual tem sido aplicada na Endodontia na busca de tratamentos mais biológicos. A revascularização pulpar tem sido observada em dentes com ápice aberto, porém há poucos estudos direcionados aos dentes com ápice formado. A angiogênese é primordial para a nutrição celular durante a regeneração tecidual. O objetivo deste estudo foi analisar o efeito do fator de crescimento endotelial (VEGF) na angiogênese após pulpectomia de canais radiculares de rato com apicigênese completa. A câmara pulpar dos primeiros molares superiores de 12 ratos machos Wistar com 13 semanas foi acessada. A polpa radicular do canal mésio vestibular foi removida e o canal instrumentado até a lima K25. Com uma lima K20, além do limite foraminal, foi induzido o sangramento periapical para o canal radicular. Os dentes do lado direito da arcada foram preenchidos com coágulo sanguíneo (GS), e nos dentes do lado esquerdo foi utilizado VEGF165 recombinante (Prospec, Israel) adicionado ao coágulo (GV). Os dentes foram selados com ionômero de vidro fotopolimerizável, e 60 dias depois os animais foram sacrificados.

A maxila foi dissecada, fixada, descalcificada e incluída em parafina. Cortes transversais seriados foram feitos e corados com hematoxilina-eosina para avaliação morfológica ou incubados com anticorpo de coelho anti-fator VIII (Bioss, EUA) para análise da angiogênese. A análise histológica demonstrou canais preenchidos por tecido conjuntivo sem presença de odontoblastos nos dois grupos. A imuno-histoquímica demonstrou positividade para o anticorpo no tecido neoformado em ambos os grupos. No grupo 1 foi predominante a marcação difusa, e no grupo 2 foi a marcação definida. Pode-se concluir que o uso de VEGF acelera a angiogênese que ocorre em canais pulpectomizados de molares com apicigênese completa.

The tissue engineering has been applied in Endodontics in search of more biological treatments. The pulp revascularization has been observed in immature teeth, but there are few studies directed to the closed-apex teeth. Angiogenesis is essential for cellular nutrition during tissue regeneration. The aim of this study was to analyze the effect of vascular endothelial growth factor (VEGF) in angiogenesis after pulp removal in rats with mature teeth. The pulp chamber of upper first molars of 12 male Wistar rats with 13-weeks-old was accessed. The pulp of the mesiobuccal root canal was removed, and the root canal was shaped up to 25K-file. Then, a 20K-file was introduced beyond the apex to induce bleeding. The teeth on the right side of the arch are filled using blood clot alone (GS) and the teeth on the left side was filled using blood clot + VEGF165 recombinant (Prospec, Israel) (GV). The teeth were coronally sealed using light-curing glass ionomer, and the animals were sacrificed after 60 days. The samples were dissected, fixed, decalcified and included in paraffin. Transverse serial sections were made, and stained using hematoxylin-eosin to morphological evaluation or expressed by immunostaining using anti-Factor VIII rabbit antibody (BIOSs, USA) to angiogenesis analysis. Morphological analysis showed root canals filled by connective tissue without the presence of odontoblasts in both groups. Immunohistochemistry showed positivity for the antibody in the new tissue in both groups, with marking defined in group 2. Diffuse marking was predominant in the group 1, and the well-maked type was predominant in the group 2. It can be concluded that the use of VEGF accelerates angiogenesis that occurs in root canal of closed-apex molars after pulpectomy.

Acurácia do diâmetro de ponta de cones de gutapercha com diferentes conicidades / Accuracy of the tip diameter on gutta-percha cones of different tapers

Objetivo: O objetivo deste estudo foi analisar o diâmetro da ponta de cones de guta-percha com diferentes conicidades, considerando a especificação do fabricante. Materiais e Métodos: Cento e quarenta cones de guta percha (Dentsply Maillefer): F2, F3, e 25, 30, 35 e 40 de conicidade .02, .04 e .06 (n = 10) foram utilizados neste estudo. Os cones foram presos em uma régua calibradora, e observados em microscópio ótico com aumento de 40x. Então, o diâmetro da ponta de cada cone foi medido com paquímetro digital. Os dados foram categorizados como corretos ou incorretos utilizando margem de erro de ±0,01 mm e submetidos ao teste Exato de Fisher (p ≤ 0,05). Resultados: Somente 4 cones de guta percha estavam incorretos, porém não houve diferença estatisticamente significativa entre os cones em relação ao padrão estabelecido pelo fabricante.Conclusão: Conclui-se que os cones principais da marca Dentsply Maillefer, independente de sua conicidade(.02, .04, .06, F2 e F3), possuem o diâmetro da ponta calibrado de acordo com a especificação do fabricante.

Avaliação da atividade antibacteriana de diferentes materiais restauradores provisórios / Evaluation of the antibacterial activity of different temporary restorative materials

O objetivo deste estudo foi avaliar a propriedade antimicrobiana de diferentes materiais restauradores provisórios: Óxido de zinco e eugenol, óxido de zinco pronto para uso [Coltosoll, resinoso (Bioplic) e guta-percha. Foram utilizadas 10 amostras de cada material acondicionados em poços de m-enterococcus ágar contaminado com Enterococcus faecolis. Poços vazios cons­tituíram o grupo controle. As placas foram encubadas a 37°C por 24 horas, e os halos de inibição foram analisados. Os dados obtidos foram submetidos ao teste de Kruskal-Wallis complemen­tado pelo teste de Dunn (p<0,05). Os resultados apresentaram que o óxido de zinco e eugenol apresentou maior halo de inibição quando comparado à guta-percha e o resinoso, porém não obteve diferença significante ao óxido de zinco pronto para uso que foi diferente somente em relação ao grupo controle de crescimento bacteriano zero. Pode-se concluir que na observação após 24 h de inserção, o Óxido de zinco e eugenol demonstrou maior efeito antibacteriano que o resinoso e a guta-percha, porém semelhante ao óxido de zinco pronto para uso.

The aim of this study was to evaluate the antibacterial activity of different temporary res­torative materiais: Zinc oxide and eugenol, ready-to-use zinc oxide, resin-based (Bioplic) and Gutta-percha. Ten samples of each material were placed into wells done on m-enterococcus agar contaminated with Enterococcus faecalis. Empty wells were the control group. The pla­tes were incubated at 3rC for 24 hours, and the inhibition zone around the materiais was analyzed. Data were submitted to Kruskal-Wallis complemented by Dunn's test (p <0.05) The results showed that the zinc oxide and eugenol showed greater inhibition zone compared to gutta-percha and resin-based material, no significant difference was found between them and ready-to-use zinc oxide. Ready-to-use zinc oxide was significant difference to control group of growth inhibition zero. It can be concluded that after 24 h, the zinc oxide and eugenol has more antibacterial effect than resin-based material and gutta-percha, but it showed similarity to ready-to-use zinc oxide.

Comparison of three obturation techniques with regard to bacterial leakage

AIM: To compare bacterial leakage in root canals obturated with the modified single-cone, lateral condensation, and continuous wave of condensation techniques. METHODS: Distobuccal root canals of maxillary molars were shaped up to ProTaper F2 and obturated with modified singlecone, lateral condensation or continuous wave of condensation technique. Two-chamber bacterial model using Enterococcus faecalis was employed for bacterial leakage evaluation for 30 days. The chi-square test was applied to evaluate differences between turbid and non-turbid samples, and the Kruskal-Wallis test was used for evaluating the time necessary for microleakage. A significance level of 5% was set for all analyses. RESULTS: The modified single-cone technique showed leakage in 73.3% of samples, lateral condensation in 66.6%, and continuous wave of condensation in 53.3%, but there were no significant differences among the groups (p>0.05). CONCLUSIONS: It can be concluded that the modified single-cone technique shows similar sealing efficacy to that of lateral condensation and continuous wave of condensation technique.

Analysis of apical fitting of .06 and .02 tapered gutta-percha master cones in root canals shaped with ProTaper rotary system

Introduction: The fitting of gutta-percha master cone is important for the obturation step. The modified single-cone technique using larger taper has provided better filling of gutta-percha than the original single-cone technique. Objective: The aim of this study was to verify if either .02 or .06 tapered gutta-percha master cone would better fit into the working length of teeth shaped using ProTaper rotary system. Material and methods: Thirty distobuccal root canals of mandibular molars were shaped using F2 ProTaper, and size 40, 35, 30 and 25 0.6 or 0.2 tapered gutta-percha cones were tested. The best fitting into the working length was recorded. The data were gathered and compared with size 25 by using Fisher's exact test. Results: There was no statistically significant difference between groups (p = 0.4915). Sizes 30 and 35 were the most used. Conclusion: It can be concluded that both .02 and .06 tapered gutta-percha master cones showed best fitting in sizes larger than 0.25 mm in root canals shaped with ProTaper F2.

Sistema wave one: comparação entre diâmetro do preparo radicular e respectivo cone de guta-percha / Wave one system: comparison between diameter of the root canal shaping and its gutta-percha cone

A adaptação do cone de guta-percha ao preparo obtido pela instrumentação é importante para a etapa de obturação. O objetivo deste estudo foi comparar o diâmetro do preparo adquirido pelo instrumento reciprocante Wave One Primary (Dentsply Maillefer, Ballaigues, VD, Switzerland) e o diâmetro de cones de guta-percha Wave One Primary. Dezesseis canais mesiais de molares inferiores foram instrumentados com a lima reciprocante Wave One Primary, e os canais moldados com resina acrílica. Após descalcificação do dente, a resina foi removida e analisada num perfilógrafo (Werth GmbH, Giessen, HE, Alemanha). Dezesseis cones de guta-percha Wave One Primary também foram analisados. Os diâmetros do terço cervical, médio e apical dos preparos (resina) e dos cones de guta-percha foram submetidos ao teste U de Mann Whitney (p=0.05). Os dados apresentaram diferença significativa em todos os terços com preparos mais amplos que os cones de guta-percha. Pode-se concluir que o diâmetro do preparo produzido pelas limas Wave One Primary não possuem correspondência ao seu respectivo cone de guta-percha, cujo preparo é mais amplo em todos os terços.

The fit of gutta-percha cone on the root canal shaping is important to the step obturation. Therefore, the aim of this study was to compare the diameter of the shaping produced by Wave One Primary reciprocating single-file (Dentsp/y Maillefer, Ballaigues, VD, Switzerland) and the Wave One Primary gutta-percha points. Sixteen mesial root canais of mandibular molars were prepared using Wave One Primary reciprocating single-file, and then they were filled with acrylic resin. After decalcification of teeth, the resin was removed and analyzed using perfilograph (Werth GmbH, Giessen, HE, Germany). Sixteen Wave One Primary gutta-percha points were also analyzed. The diameter of third coronal, medium and apical of the shaping (resin) and gutta-percha points were compared using Mann WhitneyU test (p=0.05). The data showed significant difference in ali thirds with shaping larger than gutta-percha points. It can conclude that the dia meter of shaping produced by Wave One Primary reciprocating single-file does not match the diameter of its gutta-percha point, the shaping is larger in ali thirds.

Comparison of the sealing ability of different types of glass ionomer cements in temporary restoration

Introduction: Glass ionomer cement has been used for temporary restoration; however, several formulations are available. Objective: The aim of this study was compare the linear leakage of different types of glass ionomer cement - R, F, N and C. Material and methods: Forty-four third molars were used and prepared with standardized class I cavity preparations. By using gutta-percha, the cavity height was standardized in 5 mm. The samples were divided into 4 experimental groups (R, N, F and C), and 2 control groups (positive - not restored, and negative - restored using resin). The teeth were waterproofed and immersed in 2% methylene blue. After 7 days, they were sectioned and the measurement of the dye leakage was performed by stereomicroscopy (40X) using a calibrated periodontal probe. Results: Data were analysed by Kruskal Wallis and Dunn tests. There was statistically significant differences (p = 0.002) between R and C, and R and N glass ionomer groups. C and N glass ionomer groups were similar. F glass ionomer group was similar to all other groups. Conclusion: It can be concluded that different types of glass ionomer formulations can influence the peripheral sealing of the restorative material. R glass ionomer was the most effective, while C and N glass ionomers were the least ones.

Comparação dos desobturadores ProTaper e Sistema ProTaper Convencional na remoção de material obturador durante o retratamento endodôntico / Comparison of the ProTaper retreatment and ProTaper Conventional System in the removal of filling materials during endodontic retreatment

A proposta deste estudo foi comparar os Desobturadores ProTaper e o Sistema ProTaper Conventional na remoção de material obturador durante o retratamento endodôntico. Trinta pré-molares inferiores com conduto único foram acessados e obturados pela técnica de condensação lateral. As amostras foram aleatoriamente divididas em dois grupos, e a desobturação realizada por meio dos Desobturadores ProTaper (G1) e Sistema ProTaper Convencional (G2). A quantidade remanescente de material obturador foi verificada radiograficamente em duas direções: mésio-distal e vestíbulo-lingual, e as imagens digitalizadas e analisadas com o software ImageJ. As áreas totais do canal e remanescente de material obturador foram calculados em ambas as direções, e estatisticamente avaliados co o teste de Kruskal-Wallis. Nenhum grupo apresentou remoção total da obturação, e não houve diferença significante entre os grupos em ambas as direções. Pode-se concluir que ambos deixam material obturador no canal radicular.

Odontometric reliability of Root ZX II / Avaliação da confiabilidade odontométrica do Root ZX II

Objective: This study analyzed the reliability of the electronic apex locator Root ZX II (J. Morita Corp., Kyoto, Japan) in different roots using the apical locator with the rotary unit. Methods: The working length of the roots of twenty-two upper molars was established 0.5 mm short of the apex visually, using a ruler. The teeth were fixed on an support and shaped using the ProTaper rotary system with the Root ZX II (J. Morita Corp., Kyoto, Japan) device calibrated to 0.5 Ncm and 500 rpm. Next, an F3 gutta-percha cone was introduced in the root canal and assessed visually. The data of the different canals, that is, mesiobuccal, distobuccal and lingual, were treated by the Chi-square test. Results: The Root ZX II (J. Morita Corp., Kyoto, Japan) device located the working length correctly 79% of the time and no differences were observed among the different root canals (p>0.05). Conclusion: When the Root ZX II apex locator is used with your rotary unit (J. Morita Corp., Kyoto, Japan) device, the percentage of clinically acceptable measurements is good, and the position of the root canal did not affect the working length.

Objetivo: Analisar a confiabilidade do Root ZX II (J. Morita Corp., Kyoto, Japão) utilizando o localizador apical associado com sua unidade de instrumentação rotatória, variando o tipo de raiz. Métodos: Vinte e dois molares superiores foram medidos visualmente com auxílio de uma régua, onde se estabeleceu a medição odontométrica visual em 0,5 mm aquém do limite apical. Assim os dentes foram adaptados num suporte confeccionado em resina acrílica, e instrumentados utilizando-se do sistema ProTaper em conjunto com o Root ZX II (J. Morita Corp., Kyoto, Japão) calibrado em torque 0,5 à 300 rpm no reverso automático em 0,5 mm. Após instrumentação, um cone principal foi introduzido e analisado visualmente. Os dados obtidos em diferentes raízes (mesial, distal e palatina) foram submetidos ao teste do Qui-quadrado. Resultados: Os resultados mostraram um percentual de 79% de acerto na medida preestabelecida. A análise estatística não apresentou diferença significante entre a posição dos canais (p>0,05). Conclusão: Pode-se concluir que o Root ZX II (J. Morita Corp., Kyoto, Japão) com unidade odontométrica acoplada à sua unidade rotatória apresenta bom percentual de medidas clínicamente aceitáveis, onde a posição do canal não influenciou no limite de trabalho.

Análise do tempo de trabalho da instrumentação recíproca com lima única: waveOne e reciproc / Analysis of working time of the reciprocating single file instrumentation: WaveOne and Reciproc

O objetivo deste estudo foi analisar o tempo de trabalho necessário para a instrumentação do conduto radicular utilizando-se da instrumentação reciproca alternada com lima única: WaveOne e Reciproc, Vinte canais simulados curvos foram utilizados, onde 10 amostras foram instrumentadas pelo sistema WaveOne e 10 amostras foram instrumentadas pelo sistema Reciproc, O tempo de trabalho com e sem a adição do tempo utilizado para irrigação e exploração do conduto foi cronometrado. Os diferentes terços também foram considerados separadamente, Os dados obtidos foram analisados utilizando teste de Mann-Whitney, Kuskal-Wallis e Student- Newman-Kels (p=0,05), Os resultados apresentaram diferença significante entre os grupos em ambas as situações (com e sem tempo adicional), onde o Reciproc obteve menor tempo nos terços médio e apical do que o WaveOne, Pode-se concluir que ambos os sistemas apresentaram ser bem rápidos na instrumentação do canal radicular, contudo o sistema Reciproc foi mais rápido que o WaveOne.

The aim ofthis study was to analyze the working time for endodontic instrumentation using the reciprocating single file system: WaveOne and Heciproc. Twenty curved simulated resin root canais were used, where 10 samples were shaped using WaveOne system and 10 samples using Reciproc, The working time with and without irrigation and exploration time was recorded, The thirds were also individually consídered, The data were analyzed by Mann-Whitney, Kuskal- Wallis and Student-Newman-Kels tests (p=0,05), The results showed signifficant difference between the groups on both situations (with and without irrigation and exploration time), where time needed for instrumentation of medium and apical thirds was shorter for Reciproc group than for WaveOne qroup, It can conclude that both systems are fast on the endodontic instrumentation, but the Reciproc system is faster than the WaveOne svstem.

Análise do programa INCLUSP através do desempenho escolar, visando disciplinas básicas e específicas / Analysis of Inclusp program through school performance seeking basic and specific subjects

Com a grande evolução tecnológica através do conhecimento e desenvolvimento do raciocínio lógico, hoje já é possível o ensino à distância em qualquer parte do mundo sob os mais diversos aspectos e metodologias de ensino. Visando a inclusão social de alunos menos favorecidos diversos programas vêm sendo desenvolvidos pelo governo associado às instituições de rede pública ou privada. A Universidade de São Paulo lançou em 2006 o programa INCLUSP, o qual visa ampliar o número de estudantes provenientes de escola pública à Universidade. O aluno que fez todo seu ensino médio em rede pública pode obter inscrição gratuita para o vestibular; somar até três pontos de bônus à nota, dependendo de outras avaliações (ENEM e PASUSP); após o ingresso pode contar com bolsa de apoio e incentivo para auxiliar sua permanência durante os estudos. Visto que no curso de Odontologia, as disciplinas chamadas básicas dadas no início do curso podem diferir das disciplinas ditas específicas em Odontologia dadas após cumprimento dos créditos básicos, seria viável estabelecer a relação de desempenho entre as disciplinas de diferentes naturezas. O objetivo deste estudo foi analisar a evolução dos primeiros alunos ingressantes pelo programa, levando-se em consideração as disciplinas básicas e específicas; além de fazer uma comparação entre os ingressantes pelo programa INCLUSP e pelo vestibular tradicional em 2007, 2008, 2009 e 2010 durante seu primeiro semestre de curso. Concluiu-se que o desempenho de alunos ingressantes pelo programa INCLUSP e pelo vestibular tradicional nos anos de 2007 a 2010 foram similares, e a comparação entre disciplinas básicas e específicas dos ingressantes INCLUSP 2007 mostrou que somente o curso integral obteve diferença entre as disciplinas.

With the great technological development through knowledge and logical thinking, nowadays it is possible distance learning anywhere in the world under various aspects and teaching methodologies. Aimed at social inclusion of disadvantaged students several programs have been developed by government institutions associated with public or private network. The University of São Paulo launched in 2006 INCLUSP program, which aims to expand the number of students from public school to the university. The student who attended high school in public schools can obtain free registration for the entrance exam, adding up to three bonus points to note, depending on other reviews (ENEM and PASUSP) after admission he/she may have scholarship support and encouragement to help him/her permanence during the studies. Since at the dental clinic, the subjects given known as basic early in the course may differ from specific disciplines called Dental given after completion of the basic claims, it would be feasible to establish the relationship between the performance of different natures of these disciplines. The aim of this study was to analyze the evolution of the first students entering the program, taking basic and specific disciplines into account; besides making a comparison between the freshman classes through INCLUSP or traditional admissiom examination on 2007, 2008, 2009 and 2010 during their first semester courses. It was concluded that the performance of students entering through INCLUSP program and traditional "vestibular"(admissiom examination) in the years 2007 to 2010 were similar, and the comparison between basic and specific disciplines of the INCLUSP 2007 students showed that just full time course had difference between the disciplines.

Comparação da desobturação de dentes obturados com diferentes tipos de cimentos endodônticos / Comparison of root canal filling removal of different types of endodontic sealers

O objetivo deste estudo foi avaliar a diferença da desobturação de quatro tipos de cimento (Acroseal, AH Plus, Endomethasone e Endo Rez). Foram utilizados 20 molares superiores, nos quais os terços cervical e médio foram preparados com brocas Gates Glidden 1, 2 e 3, os canais instrumentados com sistema ProTaper e obturados por condensação lateral, utilizando-se diferentes cimentos: Acroseal, AH Plus, Endomethasone e Endo Rez. Após sete dias mantidos em estufa a 37 °C, os dentes foram desobturados com limas K e Hedströen, associadas a Gates Glidden. O tempo até chegar ao limite de trabalho foi marcado com um cronômetro digital. Os dados foram submetidos aos testes de ANOVA e Tukey, e a comparação entre os tipos de raízes foi obtida pelo teste de Krukal-Wallis. Os resultados mostraram diferença significante somente entre o AH Plus e o Endo REZ (p = 0,0167), sendo que o tipo de raiz não influenciou nos resultados obtidos em nenhum dos grupos. Pode-se concluir que o cimento obturador à base de resina epóxia dificulta a desobturação do canal radicular e os cimentos à base de resina uretanodimetacrilato, óxido de zinco e eugenol, e hidróxido de cálcio apresentam similaridade.

The aim of this study was evaluate the difference of root canal filling removal of 4 endodontic sealers (Acroseal, AH Plus, Endomethasone e Endo Rez). It were used 20 upper molars shaped by Gates Glidden 1, 2 and 3, and ProTaper rotary system, then filled by lateral condensation technique using different sealers: Acroseal, AH Plus,Endomethasone e Endo Rez. After 7 days of incubation at 37°, the root canal filling removal was performed using K-file and Hedströen associated to Gates Glidden. The time to reach the working length was recorded using a stopwatch. The data were submitted to ANOVA and Tukey tests, and the comparison between root canals type wasdone by Krukal-Wallis test. The results showed significant difference just between AH Plus and Endo REZ sealers (p = 0.0167), the root canal type had not influence on the root canal filling removal. It can conclude that epoxy resin-based sealer demonstrate difficulty in removing root canal filling material, and methacrylate resin-based, zinc oxide eugenol, and calcium hydroxide sealers show similarity.