[ in vitro evaluation of the accuracy of two electronic apex locators Foramatron V and Ipex in determining working length]

Accurate determination of working length in root canal therapy is very important for success of the process. Different methods such as electronic apex locators have been introduced for determination of working length. The aim of this in vitro study was comparison of the accuracy of two electronic apex locators, Foramatron V and Ipex, in determination of working length in human single root teeth. In this in vitro study, 100 human single root, single canal maxillary incisors with developed apex without curve were used. The teeth were cleaned after extraction and stored in normal salin. After preparing access cavity, the actual length of each canal was determined by an anatomic method placing a k-file into the canal so that the file tip touched the apical foramen. After preparing the experimental environment, the teeth were placed in the model at the level of CEJ and the length of the teeth were determind with Ipex and Formatron V according to their code. The acceptable limitation was +/- 0.5 millimeter to the actual working length. After collection of data, Mac Nemar and Paired t-test were used for statistical analysis. According to the results of this study, the accuracy of length determination was 64% and 63% for Foramatron V and ipex, respectively in the range of canal length +/- 0.5 mm. There was no significant statistical difference between these two devices. There was no significant difference between Ipex and Foramatron V. Therefore, Foramatron V may be used for working length determination

[Cleaning effectiveness of two methods of instrumentation, manual and rotary; a microscopic study]

Root canal cleaning is the main purpose of canal instrumentation. Hand instruments leave more debris and smear layer on the root canal walls. The use of automated instruments is helpful in root canal cleaning. The aim of this study was comparison of hand NiTi instruments, rotary flexMaster and FKG race instruments in root canal cleaning. In this interventional and in vitro study, 75 single canal teeth with minimum curve were selected and divided into three groups of 25 teeth in each. The canals were prepared with hand NiTi file, FlexMaster and race instruments using crown down preparation technique, up to size 40. During preparation, the root canals were irrigated with 5m1 of 0 0.50% Naocl solution and at the end of instrumentation with 5 ml of normal saline. After splitting the roots longitudinally, the amount of the debris and smear layers were quantified on the basis of Hulsmann method, using a scanning electron microscope. The data were analyzed by Kruskal wallis test using SPSS statistical software. In general, flexMaster instruments left less debris than FKG race and NiTi hand instruments significantly [p<0.05]. This difference was significant in all three thirds of the canal. FlexMaster instruments left debris with the smallest size in the middle and coronal thirds of the canal but not the apical third. FlexMaster instruments left less smear layers just in the apical third of the canal significantly. No completely cleaned root canals were found with any of the three instruments. In general, FlexMaster instruments proved to have better canal cleaning in all three third of the root canal significantly