Aims of the study
To evaluate and compare the incidence of postoperative pain after root canal instrumentation using the ProTaper Ultimate rotary system and the Reciproc Blue single-file system in human permanent molars before, during, and after the root canal preparation phase. As sequentially, the patient will be enrolled and signed the terms, OHIP-14 before the beginning (baseline), an instrumentation will be performed and the measurement will be evaluated that will be measured using visual scales (NRS-10 cm VAS-0-10 cm) at intervals of 0h, 6h, 12h and 24h, 2 days, 3 days, 4 days, 5 days, 6 days and 7 days after instrumentation evaluated and compared to the bite sensitivity using an autoclaved latex device at 0h, 6h, 12h, 24h, 2 days and 3 days, OHIP-14 and 3 days after instrumentation (Figure 1). Our hypothesis is that there are no differences in performance between the different systems, but there are improvements in quality of life.
Overall design
A randomized, blind clinical trial (patient and biostatistician), will be conducted in accordance with the Consolidated Standards of Reporting Trials Statement [18,21], registered on the Brazilian Clinical Trials Registry Platform (REBEC) RBR-10kbw6nx on April 6, 2024, and approved by the Research Ethics Committee of CEUMA University (CAAE 64132322.6.0000.5084). Informed consent will be obtained from patients participating in the study [22]. Sample size calculation was performed to compare mean pain intensity, considering a confidence level of 95%, a power of 80%, and a standard deviation of 2.3 [8]. A minimum of 58 patients was determined for each group, totaling 116 patients. To compensate for possible losses, 10% was added to the sample size, totaling 128 patients, 64 per group according to the study design. These patients will be treated and screened at the school clinic CEUMA University in São Luís – MA, Brazil and allocated randomly according to the type of endodontic instrument used: Reciproc Blue (R) and Protaper Ultimate (PN), SPIRIT (figure 2). Allocation will be done by a person not involved in the endodontic treatment using the www.radom.org software. After patient history and assessment of the need for endodontic treatment of the tooth, information about each patient and the instrumentation technique assigned to the patient will be written and sealed inside an envelope, which will then be given to the operator. After determining the real working length (RWL), the operator will open the envelope and use the instrumentation technique assigned to that patient. Any violations of inclusion and exclusion criteria, reasons for randomization failure, including significant deviations from the protocol, loss to follow-up, voluntary withdrawal, and study termination, will be reported to the study statistician. All data obtained during the research will be simultaneously stored in an electronic spreadsheet, an online spreadsheet where everyone involved in the research will have access, but only one operator will be able to change it.
Participants:
To be eligible to participate in this study, individuals must meet all of the following criteria:
- aged between 18 and 50 years old
- molars diagnosed with pulp alterations requiring endodontic treatment
- absence of pain
- absence of radiographic lesions
- canal curvature of up to 25° according to the Schneider method [23].
Individuals meeting any of the following criteria will be excluded from participation in this study:
- presence of internal or external resorption
- trismus
- ankylosis
- periodontal condition index less than 3
- systemic disease
- dental positioning outside normal alignment
- history of trauma
- pregnancy
- presence of teeth requiring endodontic retreatment [24]
Informed consent and biospecimens
Informed consent will be obtained from all participants. Biospecimens will not be collected in this study.
Treatment
Instrumentation will be performed in a single session and will be analyzed for painful symptoms and quality of life. Deep local anesthesia will be applied using 2% mepivacaine with 1/80,000 epinephrine (Nova DFL, Taquara, Rio de Janeiro, Brazil). Subsequently, the access cavity will be prepared, and the tooth isolated using rubber dam. Canal emptying will be performed with K-type files (Dentsply Maillefer, Ballaigues, Switzerland), size 15, in the presence of 2.5% sodium hypochlorite solution (Fórmula e Ação, São Paulo, SP, Brazil). The initial working length will be determined with a foraminal locator (Dentsply, Munich, Germany) set at 1 millimeter from the radiographic apex. Later, root canal preparation will be performed with one of the following instrumentation systems according to the manufacturer's instructions. A 2.5% sodium hypochlorite solution/pH 11 will be used, with all teeth receiving the same volume of irrigating solution (15ml) during instrumentation. At the end of this, they will receive 2 ml of 17% EDTA, which will remain in the canal for 3 minutes, and final irrigation with 2ml of 2.5% sodium hypochlorite [2].
For instrumentation with the reciprocity kinematics - Reciproc Blue (VDW, Munich, Germany), selection of the initial instrument will be made after radiographic examination, assessing the root canal thickness and with the help of an initial size #15 file assessing the free access to the real working length. After selection, these instruments should be introduced and removed with a range of 3 millimeters, after three back-and-forth movements until reaching the RWL. After completion and/or after each instrument, the root canal path will be recapitulated with a manual #15 file up to the RWL. The protocol used for rotary instrumentation of the ProTaper Ultimate system will be performed according to the manufacturer's recommendation: after exploration/emptying and determination of the real working length, the sequence of instruments (Slider, Shaper, F1, F2, and F3) according to the canal anatomy and with back-and-forth kinematics along the root canal. For both systems, the VDW Silver motor (VDW, Germany) will be used. For the Reciproc system, it will be used in RECIPROC ALL mode (speed of 400 rpm and 2.5 Ncm of torque), while for the ProTaper Ultimate system, it will be programmed at a speed of 400 rpm, 4-5.2 Ncm of torque, and continuous movement [25].
After the completion of instrumentation, the canals will be dried by aspiration with cannulas (Ultradent Products Inc, Salt Lake City, Utah, USA), complementing the drying with absorbent paper points from the Reciproc Blue (VDW, Germany) and Protaper Ultimate (Dentsply Maillefer, Ballaigues, Switzerland) file systems, and then temporary restoration will be performed with Vitro Fill LC restorative glass ionomer (Nova DFL, Taquara, Rio de Janeiro, Brazil). The working time from the beginning to the end of the instrumentation of each root preparation system will be counted and recorded.
After root canal preparation, patients will receive a form with two pain assessment scales: the numerical rating scale (NRS) and the visual analog scale (VAS-0-10 cm). The NRS is a ten-point scale (0= no pain, 1 - 2= mild pain, 3 - 4= moderate pain, 5 – 7= considerable pain, and 8 - 10= severe pain), with the first and the second being 20 points (0-100 with 5-point intervals, with closer to 0 indicating no pain and closer to 100 indicating worst possible pain). Patients will fill out the form according to the level of spontaneous pain every 0, 6, 12, 24 hours and daily for 2, 3, 4, 5, 6, and 7 days. In addition to these, the patient will be instructed to bite on an autoclaved latex device (3 x 2 cm) to simulate biting sensitivity, instructed to bite on the device in the region of the treated tooth at 0, 6, 12, 24 hours, and 2 and 3 days and record on the form the presence or absence of pain provoked by biting the device. The patient will be instructed to set alarms on their cell phone to remember to fill out the form correctly, and on the seventh day the operator will remind them to appear the next day to submit the completed data.
Each participant will answer, during the anamnesis, after 3 days of instrumentation and after 3 days of completion preparation, a questionnaire aimed at measuring the impact of oral health on quality of life (OHIP-14), reporting whether they have always, often, occasionally, rarely, or never experienced any of the problems assessed by the 14 items of the OHIP. The items included in the questionnaire are grouped into seven sections: functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and disadvantage. A questionnaire containing demographic, socioeconomic, and clinical characteristics information will be applied to the patients. The patient will be referred for root canal filling after 7 days. In cases of exacerbation of an infectious process, fracture that compromises the integrity of the tooth, flare up or lack of contact or interest of the patient in continuing the process, these will be criteria for modifying the treatment or excluding it from the research, observing the cause and the most appropriate solution according to the literature. All adverse events will be systematically collected and recorded when spontaneously reported by participants. Investigators will assess the severity and causal relationship of adverse events. Serious adverse events will be reported to the Research Ethics Committee (CEP) of CEUMA University (CAAE 64132322.6.0000.5084), while non-serious events will be reported in accordance with regulatory guidelines with auxiliary care and judgment. Adverse events, if necessary, may be withdrawn from the study. Other undesirable effects will be documented and managed in a similar manner. All data will be recorded in a secure and confidential database, with access restricted to the principal investigators and authorized personnel. These procedures ensure the safety of the participants and the integrity of the study.
Assessments
The treatment will be performed by calibrated endodontists, and the bio-statistical evaluation of the results will be conducted by dentists not involved in the restoration procedures and, therefore, blinded to the group allocation.
Data analysis
The data will be analyzed using multivariate analysis of variance and t-tests. Differences will be considered statistically significant when p < 0.05 and with a confidence level of 95%.