A total number of 66 patients with 151 canals were treated at endodontic department, Jordan University Hospital. Informed written consent was obtained from each patient following ethical committee approval from the deanship of academic research at the University of Jordan.
The patients were 30 males and 36 females between 12–65 years old with a mean of (35.3 ± 15.5). Patients that used heart pacemakers were excluded. All patients were referred for endodontic treatment and were treated by the author. A data sheets were used for recording the patient's profile, chief complaint, history of present illness, medical history, dental history, investigations, diagnosis and treatment planning, vitality of the tooth on access as determined by bleeding, working length measurements, procedures done, total number of radiographs, number of radiographic retakes, total number of visits, the incidence of flare-ups (that require unscheduled endodontic intervention), with all of the corresponding radiographs (film mounts, Dentsply RINN, UK).
A preoperative periapical radiograph (AGFA, Dentus M2, Heraeus, Kulzer, Germany) placed in a film holder (Hawe Super-Bite, Kerr Hawe SA, Switzerland) was taken (Trophy Vincennes France, HT KV 65, mA 8). After administration of local anesthesia (Persocaine-E® Daron Pakhsh, Iran) pulp cavity was accessed using a straight fissure diamond bur in a high speed contrangle hand piece under abundant water spray followed by small round bur in a slow speed hand piece, after initial access the tooth was isolated using rubber dam. The walls of the access cavity were adjusted using endo Z bur (Dentsply Maillefer, Ballaigues, Switserland), the entrances of the root canals were irrigated with 2.5 % sodium hypochlorite solution and dried by aspiration, no attempt was made to clean debris or pulp tissue remnants prior to introducing a size 10 k-file (Dentsply Maillefer, Ballaigues, Switserland) into the canals. The Tri Auto ZX® was used on EMR Mode- Electronic measurement of a root canal based on manufacturer's recommendations (group I). The lip-clip (contrary electrode) was placed in the corner of the patient's mouth and the file holder was attached onto the shaft of the hand file. The size 10 K-file was advanced apically into the canal until the beeping sound and the light emitting diode (LED) marked APEX on the panel began to glow, indicating that the tip of the file had reached the anatomical end of the canal in the periodontium. The file was withdrawn with a slow counterclockwise turn until the red LED APEX light went out, suggesting that the tip of the file was at the predetermined length of the apical constriction. At that time, the 0.5 mm green LED light illuminated and a rapid tone was heard. The distance from the file tip to the silicone stop was then measured to an accuracy of 0.5 mm (Minifix, VDW, Germany) and registered as working length. In group (II) with a size 10 or 15 K-files set on a pre-estimated electronic length inside root canals a working length radiograph (AGFA, Dentus M2, Heraeus, Kulzer, Germany) placed in a film holder (Hawe Endo-bite (anterior/posterior), Kerr Hawe SA, Switzerland) was taken (Trophy Vincennes France, HT KV 65, mA 8). The radiographic length was then recorded. If any discrepancy between the electronic length and the radiographic length was found then a decision was made on the appropriate adjustment based on both the radiographic picture aided by the electronic measurements. Radiographs were repeated if root apices were not clear.
The patients were randomized into group I and group II alternately as they referred for treatment.
Cleaning and shaping was done using flexofiles size 15–40 (Dentsply Maillefer, Ballaigues, Switserland) in a step back technique, followed by nickel titanium protaper rotary files (Dentsply Maillefer, Ballaigues, Switserland) in Tri Auto ZX hand piece pre set on the manual mode, accompanied by copious irrigation of sodium hypochlorite 2.5%, before obturation the canal was thoroughly dried, AH26 was the sealer used with hot lateral condensation of conventional gutta percha (size medium, medium-fine, Meta Dental Co Ltd, Korea) using hand spreader (A30 Maillefer, Switserland) heated in a bead sterilizer. A postoperative periapical radiograph (AGFA, Dentus M2, Heraeus, Kulzer, Germany) placed in a film holder (Hawe Super-Bite, Kerr Hawe SA, Switzerland) was taken (Trophy Vincennes France, HT KV 65, mA8). Root canal treatment was finished in one to three visits according to pathological status, time available, the difficulty of the case and patient cooperation.
Periapical post-obturation radiographs were examined on x-ray illuminator and by the aid of magnifying loupes 3.5 × (XL advantage, 42 cm working distance, 8.1 field diameter, Keeler, UK). Distances from the end of root canal filling to the radiographic apex were measured in millimeter to an accuracy of 0.5 mm twice at two separate occasions and the means were calculated and recorded.
The data were analyzed using SAS system and T. tests were carried out. Statistical significance was considered to be P ≤ 0.05.