Effect of rotational speed on root canal preparation with hero 642 rotary Ni-Ti instruments

The purpose of this study was to evaluate the influence of Hero 642 rotary Ni-Ti instruments driven at 300, 400, or 600 rpm on root canal straightening, loss of working length, and instrument breakage. Sixty mesial root canals from extracted human mandibular molars were divided into 3 groups of 20 each and were instrumented at the aforementioned rotational speeds with a crown-down technique. Using a digital intraoral radiography system directly on the images of pre- and postoperative radiographs, degrees of canal curvatures were measured and recorded. Statistical analysis showed that final canal curvatures and working lengths were significantly reduced compared with those of original values in each group (p 0.05). No file breakage was observed in any of the groups

Radiographic prevalence of root canal ramifications in a sample of root canal treatments in a Brazilian Dental School Prevalência radiográfica de ramificações do canal radicular em uma amostra de tratamentos endodônticos em uma Faculdade de Odontologia Brasileira

The aim of this study was to radiographically investigate the presence of root canal ramifications found after endodontic treatment, and to determine any relationship between their presence and the type of the auxiliary chemical substance used. The study evaluated 1,470 endodontic treatments performed by final year undergraduate students at the Dental School of Piracicaba, State University of Campinas (UNICAMP), SP, Brazil, during the period from 1998 to 2000. The X-rays taken during treatment were evaluated in order to establish the presence of ramifications of the root canal system. The initial X-ray did not show the presence of any canal ramifications. After filling, X-rays showed only 3 ramification types: 3.06% of lateral canals, 2.99% of apical deltas, and 0.1% of interradicular canals. The maxillary premolars showed the highest number of lateral canals (n = 13), followed by mandibular premolars (n = 10) and maxillary incisors (n = 10). Apical deltas were mostly found in mandibular molars (n = 14), followed by maxillary incisors (n = 9). Only mandibular molars had interradicular canals. The detection of ramifications increased with the use of EDTA. However, no statistically significant relationship was found between the type of auxiliary chemical substance used and the number of root canal ramifications detected after root canal filling. It was concluded that the frequency of root canal ramifications found radiographically was low in treatments performed by undergraduate students.<br>O objetivo deste estudo foi investigar radiograficamente a presença de ramificações do canal radicular encontrada depois do tratamento endodôntico, e determinar qualquer relação entre a presença destas e do tipo de substância química auxiliar usada. O estudo avaliou 1.470 tratamentos endodônticos executados pelos estudantes do último ano da Faculdade de Odontologia de Piracicaba, Universidade Estadual de Campinas (UNICAMP), SP, Brasil, no período de 1998 a 2000. Foram avaliadas as radiografias feitas durante o tratamento para verificar a presença das ramificações dos sistemas de canais radiculares. A radiografia inicial não mostrou a presença de qualquer ramificação. Depois da obturação as radiografias mostraram apenas 3 tipos de ramificação: 3,06% de canais laterais, 2,99% de deltas apicais e 0,1% de canais interradiculares. Os pré-molares superiores mostraram o maior número de canais laterais (n = 13), seguidos pelos pré-molares inferiores (n = 10) e incisivos superiores (n = 10). Deltas apicais foram encontrados principalmente em molares inferiores (n = 14), seguidos por incisivos superiores (n = 9). Apenas molares inferiores apresentaram canais interradiculares. A detecção de ramificações aumentou com o uso do EDTA. Entretanto, nenhuma relação estatisticamente significante foi encontrada entre o tipo de substância química auxiliar usada e o número de ramificações visualizadas após a obturação dos canais radiculares. Foi concluído que a freqüência de ramificações do canal radicular encontrada radiograficamente é baixa em tratamentos executados por estudantes universitários