To show whether One Shape rotary system differs from Reciproc reciprocating system in postoperative pain in patients with symptomatic irreversible pulpitis.

Patients in the clinic of endodontics at the faculty of oral and dental medicine, Cairo University, Urban area, Cairo governorate, Egypt.

The dental Unit is Adec 200 U.S.A. The x-ray Machine is ViVi, S.r.I, Italy The x-ray films are Kodac, speed D, size 2. The operator is master degree student in the department of Endodontics. No dental assistant Time: 2016-2017 Diagnosis The diagnostic data will be collected in a case report form by the investigator and confirmed for eligibility with the assistant supervisor and will be enrolled in the study in the same day.

Diagnosis is done by the following:

Recording the chief complaint and history of pain Clinical examination will be evaluated for (sensitivity) of pulp tissues using cold testing (by using Green Endo ice), electric tester.

The patient should experience prolonged response to cold testing and positive response to electric pulp testing Radiographic examination: There should be no periapical radiolucency except for widening periodontal ligaments.

Intervention Full medical and dental history using a schematic dental chart will be obtained from all patients treated during this study. Each tooth will be evaluated for vitality (sensitivity) of pulp tissues using electric pulp tester.

The patients will be randomly divided into 2 group:

Experimental group Reciproc single-file reciprocating instrumentation system. Control group One Shape single-file rotary instrumentation system. Sequence of Procedural steps Preoperative pain will be assessed by NRS before administration of anesthesia. Local anesthesia will be achieved using 2% lidocaine (1:100,000 adrenaline). An access cavity will be performed using round bur and Endo-Z bur1.

. The tooth will be properly isolated with rubber dam. Working length will be determined using an electronic apex locator2, and working length will be confirmed by radiograph using K-file3. Then the working length will be established at 0.5 mm up to the radiographic apex.

Canals will be explored with hand K-file ISO sizes 10, 15, 20. Mechanical preparation for both groups will be as follows

Experimental group Canals will be instrumented using Reciproc4 reciprocating system set on an electric motor5, with adjusted torque and speed according to the manufacturer's instruction.

There is no need for coronal preflaring with a Gates Glidden drill or an orifice opener since the design of the Reciproc instrument allows any obstructions in the coronal third to be removed, as claimed by the - Reciproc file selection: R40 (40/0.06) manufacturer.

Control group Coronal preflaring will be performed using Gates Glidden drill. Canals will be instrumented using One Shape1 single-file (25/0.06) set on an electric motor2 with adjusted torque and speed according to the manufacturer's instructions.

For wide canals, One Shape Apical (30/0.06, 37/0.06) will be used. The rotary files will be introduced inside the canal using EDTA gel3.. Canals will be irrigated with 2.5% sodium hypochlorite solution between every subsequent instrument. It is prepared by adding 11 ml of sterile distilled water using a 27 gauge needle fit to 5ml disposable plastic syringe placed in the canal space without binding

Canals will be dried with sterile paper points and obturated using lateral condensation technique. A spreader will be used to allow space for auxiliary cones, with resin-based root canal sealer.

The tooth will be sealed by temporary restoration, and postoperative pain will be assessed immediately after the end of treatment.

The patient will be phone called for follow up after 6, 12, 24, 48 and 72 hours.

The patient will be instructed to return to complete the treatment procedures until placing a full-coverage restoration.

The patient will be instructed to take one tablet 600 mg Ibuprofen if he/she experiences severe pain.

Outcomes Primary Outcome :Intensity of postoperative pain will be measured using a numerical rating scale (NRS) immediately after the end of treatment, 6, 12, 24, 48, and 72 hours after the end of endodontic treatment.

The numerical rating scale (0-10 scale) consists of a line anchored by two extremes "0: no pain" and "10: severe pain"; patients will be asked to choose the mark that represents their level of pain from 0 to 10. Pain level will be assigned to one of 4 categorical scores:

0, None; 1, Mild (1-3); 2, Moderate (4-6); 3, Severe (7-10)

0: None

1. Mild (1-3)
2. Moderate (4-6)
3. Severe (7-10)

Secondary outcome Number of analgesic taken by the patient to decrease postoperative pain up to 3 days after the end of endodontic treatment will be recorded by the patient with time intervals.

Participant Timeline:

After the patient is found eligible, he/she will be randomly assigned to either the control (One Shape) or experimental group (Reciproc) and will be treated in a single visit. At the end of treatment, patients will be asked to record postoperative pain by NRS immediately, then after 6,12,24,48 and 72 hours.

Inclusion Criteria:

• i. Age 25-45years old. ii. Males or Females. iii. Mandibular premolar teeth with:

  • Single canal
  • Preoperative sharp pain.
  • Vital response of pulp tissue.
  • Normal periapical radiographic appearance or slight widening in lamina dura.

Exclusion Criteria:i. Patients who have already consumed preoperative medication, such as analgesic, non-steroidal or steroidal anti-inflammatory drugs, within 12 hours before treatment.

ii. Patients who have more than one tooth in the same quadrant and/or opposite quadrant that require an endodontic treatment.

iii. Pregnant females. iv. Patients having significant systemic disorder. v. If antibiotics have been administrated during the past two weeks preoperatively.

vi. Patients having bruxism or clenching. vii. Teeth that have:

• Non-vital pulp tissues.
• Association with swelling or fistulous tract.
• A pocket depth greater than 5 mm.
• Previous endodontic treatment.