First part was to determine the frequency and direction of dilaceration of permanent upper lateral incisors.
•Second part: cases in which endodontic treatment had failed were examined to evaluate whether this failure is related to missing the true direction of the root.
•N= 480 extracted permanent upper lateral incisors collected from different countries in first part.
•In first part: visual inspection of 480 extracted upper lateral incisors teeth. • In second part: 48 teeth were selected from the original sample, and its randomly ,and x-rays was used in different angles
•In third part: 442 endodontically treated permanent upper lateral incisors expose to x-ray in different angles to view dilacerations.
Most highlighted Results:
1.The most common dilacerations is distolabial (52.1%) of cases
2.The least frequent was mesial dilacerations (2.1%) of cases
the results of this study can explain the higher incidence of failure in endodontically treated single rooted teeth, as compared to the failure rate in multirooted teeth