Abstrait

Accuracy of Working Length Determination using IOPA Grid Technique and Apex Locator: An In vivo Study

Swapna Sachdev

Background: The study consisted of 40 teeth which comprised of 10 maxillary incisors, 7 mandibular incisors, 5 maxillary canines, 2 mandibular canines, 3 maxillary premolars, 4 maxillary molars and 9 mandibular molars (68 canals). The working length of these teeth were measured by apex locator (Morita ZX), confirmed by a diagnostic radiograph and tooth length by IOPA on which a grid was fixed with a salotape. The radiographs were taken by paralleling technique with the help of a cone beam indicating device. These teeth were further divided into three groups and correction factors of 1.5 mm, 1 mm and 0.5 mm were applied to the values of the tooth length obtained by the IOPA grid technique according to the criteria given by Morfis et al. It was discovered in the process that maxillary and mandibular canines couldn’t be put into any of the groups so a fourth group was made which consisted of these teeth and probability of the correct correction factor was analysed. Result: A Statistical analysis of the data indicated that the 49% of the cases in whole study showed 1 mm as the correct correction factor to be deducted from the tooth length measured by the IOPA grid. Conclusion: IOPA grid can prove as substitute in maximum number of cases in case of absence of a Apex locator.