No apical enlargement size allowed the root canal walls to be prepared completely. Apical third cleanliness could be predicted by instrument diameter.

Objective:to investigate the influence of three different rotary systems for cervical flaring on establishment of the real working length. Material and methods: Thirty mandibular first molars were submitted to conventional endodontic access and initial working length measurement, followed by irrigation/suction of the pulp chamber with 5% sodium hypochlorite. Teeth were randomly divided into 3 groups (n=10) and cervical flaring of the mesiobuccal canals were performed using one of the following instrument systems: Group 1 – Gates-Glidden burs; Group 2 – Orifice Openers; Group 3 – La Axxess system. Two subsequent numbers of instruments of each rotary system were used and the final working length was recorded. A digital calyper was used to record the working length, in millimeters, to investigate a possible discrepancy between initial and final measurements.Results:Analysis of variance (Anova) na Tukey test revealed statistical difference between Group 1 and Groups 2 and 3 (p£ 0.05).Conclusions:all groups presented shorter working length after cervical flaring; groups prepared with instruments La Axxes and Orifice Opener presented the best results among the systems studied.

This study used computed tomography (CT) to compare apical canal transportation in mesiobuccal canals of maxillary molars prepared with different techniques. Sixty teeth were assigned to 3 groups (n=20), according to the technique used for root canal instrumentation: hand instrumentation with K-Flexofiles, K-Flexofiles activated by an oscillatory system and ProTaper NiTi rotary system. Pre and post-instrumentation CT images were obtained 3 mm short of the apical foramen and were superimposed to compare canal transportation. Data were analyzed statistically by ANOVA and Tukey's test using the SPSS software (α=0.05). In the buccal direction, the manual technique produced significantly less canal transportation than the oscillatory technique (p<0.05) and both were similar to the rotary technique (p>0.05). In the distal and distopalatal directions, the oscillatory technique produced more canal transportation (p<0.05). In the mesiopalatal direction, the oscillatory technique produced more canal transportation than the manual technique (p<0.05), and both were similar to the rotary technique (p>0.05). In conclusion, all techniques produced canal transportation, and the oscillatory technique produced the greatest removal of root dentin toward the innerside of the root curvature.

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Objectives: This study aimed to evaluate vital pulp tissue removal from different endodontic instrumentation systems from root canal apical third in vivo. Materials and Methods: Thirty mandibular molars were selected and randomly divided into 2 test groups and one control group. Inclusion criteria were a positive response to cold sensibility test, curvature angle between 10 and 20 degrees, and curvature radius lower than 10 mm. Root canals prepared with Hero 642 system (size 45/0.02) (n = 10) and Reciproc R40 (size 40/0.06) (n = 10) and control (n = 10) without instrumentation. Canals were irrigated only with saline solution during root canal preparation. The apical third was evaluated considering the touched/untouched perimeter and area to evaluate the efficacy of root canal wall debridement. Statistical analysis used t-test for comparisons. Results: Untouched root canal at cross-section perimeter, the Hero 642 system showed 41.44% ± 5.62% and Reciproc R40 58.67% ± 12.39% without contact with instruments. Regarding the untouched area, Hero 642 system showed 22.78% ± 6.42% and Reciproc R40 34.35% ± 8.52%. Neither instrument achieved complete cross-sectional root canal debridement. Hero 642 system rotary taper 0.02 instruments achieved significant greater wall contact perimeter and area compared to reciprocate the Reciproc R40 taper 0.06 instrument. Conclusions: Hero 642 achieved higher wall contact perimeter and area but, regardless of instrument size and taper, vital pulp during in vivo instrumentation is not entirely removed.

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Introdução: as variações anatômicas e a complexa anatomia do primeiro molar superior são um desafio constante quanto ao diagnóstico e ao sucesso da terapia endodôntica. A alta taxa de resultados negativos no IntroduçãoA anatomia da câmara pulpar, devido à sua complexidade e variabilidade, é um desafio para o cirurgião-dentista. O conhecimento das caracterís-ticas mais comuns e de suas possíveis variações é fundamental, pois a não instrumentação de um canal radicular pode levar ao insucesso no tratamento endodôntico 1 . O primeiro molar superior (1ºMS) é submetido ao tratamento dos canais radiculares frequentemente, devido ao fato de ser um dente que irrompe precocemente na cavidade bucal, aproximadamente, aos 6 anos de idade. Na maioria das vezes, a falta de cuidado das crianças e dos pais com a higiene oral leva à ocorrência de cáries e restaurações extensas, que podem evoluir para um quadro com envolvimento pulpar e consequente necessidade de terapia endodôntica. A alta taxa de falhas no tratamento desse elemento dentário está normalmente relacionada à presença de um segundo canal na raiz mésio-vestibular (MV) 2 . Em um estudo clássico, os autores classificaram os canais em três diferentes tipos, por meio da secção de 208 raízes mésio-vestibulares: tipo I canais únicos, tipo II -dois canais que iniciam separada-