2.1. Sample Selection
calculus, fractures, tooth’s mesial and distal aspects, caries
CARIES
After obtaining the approval from the UDHS ethical committee (REC-20-03-23-02-S), sixty-five human extracted teeth were used in this study. The inclusion criteria were single-rooted intact mature teeth with straight canals without caries, cracks, and fractures and with no abnormal anatomy or previous root canal treatment. Teeth were kept for 48 h in 2.5% NaOCl to remove organic debris. Then, the external root surfaces were scaled with an ultrasonic scaler to remove any calculus or soft tissue washed with distilled water, and stored in saline until they were used.The teeth were later decoronated by cutting the coronal part to standardize the length to 15 mm. Radiographs were taken from each tooth’s mesial and distal aspects to ensure that the apices were closed; the root apex was sealed with sticky wax.