To determine if the presence of a buccal curvature in palatal roots of maxillary molars affected the ability of a clinician to accurately determine working length.
•N= 27 extracted max molars , Excluded: teeth with apical root resorption or if apical foramen was not patent.
•radiographs obtained from a MD direction using parallel technique and conventional film.
•based on RGs, teeth were then sorted by palatal curvatures into J- type and C-type. and the angle of the palatal root curvature was determined using schneider’s method.
•A straight line access was prepared and a #20 NiTi file was placed into the palatal canal until the tip was visible at the apical foramen.
•Each tooth was placed on a sensor in a BL direction next to the niti file and a calibration wire. radiographs obtained.
•using the digital ruler.
•The actual (file) and radiographic (tooth) lengths were measured. •Analysis of covariance was used to test for a relationship between the amount of curvature (in degrees) and the actual – radiographic lengths difference (in millimeters). Also, differences in types (J versus C) were compared.
Most highlighted Results:
•Radiographic length appeared shorter on average than the actual length. •Canal curvatures larger than 25 degrees had differences greater than 0.5 mm between actual & radiographic lengths.
•There was no significant difference between the J- and C- types.
results show the limitation in using RGs for WL determination.
(combination of RGs and EAL should be used).