Reduction of Post-endodontic Pain After 3 Irrigation Regime

Two hundred and sixteen of 245 patients (119 women and 97 men) aged 18-65 years were referred and incorporated in this research while 29 were excluded as not meeting the inclusion criteria. All patients presented with a vital upper or lower molar, premolar or anterior teeth selected for conventional root canal treatment for prosthetic reasons.

Patients rejecting to join the study or rejecting, single-visit root canal treatment, consuming analgesics or NSAIDs were excluded too. All participants were informed on the goals, risks and strategy of the study, and written informed consent permissions were gained previous their enrollment.

Random Selection of instrumentation groups. An investigator who had not contributed in the study made the randomization arrangement using a computer random table generator (www.random.org). Each patient receive a consecutive number. A total of 216 patients met the inclusion requirements and were incorporated in the study. Of the sample of 216 teeth, 72 were randomly assigned to the one of the 3 irrigating methods. Treatment was performed by 3 experienced endodontists; each prepared 72 teeth, 24 per method.

Treatment Protocol All patients were anesthetized with two carpules of articaine 2% with epinephrine 1:200,000 (Septodont, Saint-Maur des-Fosses, France). In cases in which supplemental anesthesia was needed, intraligamental anesthesia (2 mL articaine 2%) was administered. For the upper teeth, the 2 carpules were administered by gradual infiltration in the buccal vestibule. For the lower teeth, 1.5 of the carpules was used for an inferior alveolar nerve block and the other 1.5 for a gentle buccal infiltration around the tooth to be treated.

After absolute isolation using rubber dam, the tooth was disinfected with 5.25% NaOCl. Preparation of the access cavity was performed using # 331 bur (Dentsply International, York, PA), with high-speed and water cooling. 5.25% NaOCl was used to clean the coronal cavity. The root canals were carefully probed with #10 K-type hand files (Flex-R files, Moyco/Union Broach, York PA, USA).

REDTA (Roth International, Chicago, IL) lubricant was located at the entry of the canals. Working length was determined with a #15 k-file and the Root ZX electronic device (J Morita, Irvine CA, USA), followed by subtracting 0.5 mm from the measurement, which was confirmed radiographically (Schick Technologies, NY, USA). Cervical and middle thirds of the root canal was flared with a K3XF 25/10 rotary instrument (Kerr Endo, Orange County, CA) at 500 rpm. The root canal was irrigated with 3 mL 5.25% sodium hypochlorite (NaOCl). A glide path to the WL was the established.

For mechanical preparations, all instruments were used with a micro motor (VDW Silver Motor, VDW, Munich Germany). Torque and rotation were preset for each Reciproc instrument. Rotary Ni-Ti instruments were used in continuous reciprocating mode.

Dentinal debris was eliminated from the file with a gauze, instantaneously to the instrument change after 2-3 in-and-out (pecking) movements (Reciproc) following the manufacturers' recommendations. Each root canal was irrigated with 2.5mL 2.6% NaOCl. Irrigation was performed using a 24-gauge needle (Max-I-Probe; Tulsa Dental, York, PA) and a 31-G NaviTip needle (Ultradent Products Inc, South Jordan, UT) when reaching the WL after each instrument insertion. A size #10 K file was used to maintain WL after each Reciproc instrument.

Group A. The R25 (size 25/ .08) instrument was used in thin and curved root canals, and R40 files (40/ .06) were used in wide root canals. Three in-and-out pecking motions were used with an amplitude of not more than 3 mm until reaching the estimated working length. Patients assigned to this group receive a final irrigation with 5 mL cold (8oC) 17% EDTA followed with 20 mL cold (8oC) sterile saline solution delivered to the WL using a cold (8oC) sterile microcannula attached to the Endo Vac System (Kerr Endo) for 5 minutes.

Group B. Canals were prepared as in group A, Patients assigned to this group receive a final irrigation with 5 mL cold (2.5oC) 17% EDTA followed with 20 mL cold (2.5oC) sterile saline solution delivered to the WL using a cold (2.5oC) sterile microcannula attached to the Endo Vac System (Kerr Endo) for 5 minutes.

Control group (CG). The R25 (size 25/ .08) instrument was used in thin and curved root canals, and R40 files (40/ .06) were used in wide root canals. Three in-and-out pecking motions were used with an amplitude of not more than 3 mm until reaching the estimated working length. Reciproc instruments were used in one tooth only (single use). Patients assigned to this control group were treated identically to the experimental groups, except that receive a final irrigation with 5 mL (room temperature) 17% EDTA followed with 20 mL (room temperature) sterile saline solution delivered to the WL using a sterile microcannula attached to the Endo Vac System (Kerr Endo) for 5 minutes.

After instrumentation, the root canals were irrigated with 1 mL 2.6% NaOCl, agitated ultrasonically. Ultrasonic activation was performed using an Irrisafe ultrasonic 20.00 tip (Satelec, Merignac, France) at 50% power of the MiniEndo ultrasonic unit (Kerr Endo) with the tip placed 3 mm from the working length for 30 seconds per root canal.

Each experimental and control group received a final irrigation with the irrigant described above, to eliminate the smear layer and reduce post-endodontic pain. Caution was taken to ensure that the micro cannula would suction correctly by detecting the system's transparent evacuation tube. In case there was any obstruction, the micro cannula was instantly substituted.

Recapitulation of working length was performed again by using an apex locator as described before using #35 and #40 files.

The root canals were dried with disinfected paper points and obturated at the same visit. Gutta-percha cones (Dentsply Maillefer) were laterally compacted with #20 nickel-titanium spreaders (Dentsply Maillefer) and AH-plus as the sealer (Dentsply Maillefer). The access cavities of anterior and posterior teeth were etched and repaired with Fuji IX (GC Corp, Tokyo, Japan).

Assessment of Post-endodontic pain and Statistical Analysis After these irrigation regimens, the patients were informed of the probable incidence of pain for days following RCT and received a survey form (VAS questionnaire) to be finished and returned three days after. In it, they proof the presence/absence of post-endodontic pain. The pain level was measured using a validated pain scale known as the VAS. The pain VAS is a continuous scale comprised of a horizontal line, which is 10 cm in length. For pain intensity, the VAS is anchored by ''no pain'' (score of 0) and ''pain as bad as it could be'' (score of 10). The cut points on the pain VAS are no pain (0-0.5 cm), mild pain (0.6-4.0 cm), moderate pain (0.45-7.4 cm), and severe pain (7.5-10 cm). The pain VAS was completed by the patients. The patients were asked to put a mark perpendicular to the pain VAS line at the point that indicated their pain severity during the 3 days after the endodontic treatment.

Two hundred and ten of the 216 surveys were returned correctly returned. Of these, 69 belonged to the group A, 70 to group B and 71 to the Control group. The missing 6 questionnaires were returned one day later and were included in the data analysis.

The outcomes for the groups A, B and CG associated to occurrence (yes/no), level (mild, moderate, severe), and interval (days) of post-endodontic pain were evaluated, and related to the following diagnostic factors: condition of tooth (all vital), occurrence or nonappearance of pre-operative pain, group of teeth (molar/premolar or anterior), or location (Maxillary, Mandibular).