In vivo evaluation of painful symptomatology after endodontic treatment with or without the use of photodynamic therapy

Abstract

Context:

Postoperative pain control after endodontic treatment is important to maintain patient comfort.

Aim:

The aim of this prospective clinical study was to evaluate the postoperative symptomatology of endodontic treatments performed in a single session, with or without photodynamic therapy (PDT), using Reciproc #40 file in necrotic unirradicular anterior teeth.

Materials and Methods:

In a prospective clinical study, 40 teeth indicated for endodontic treatment were treated by a single endodontist according to a preestablished protocol. The teeth were randomly divided into two groups (n = 20): control group (CG) and laser group (LG). After 24 h, 72 h, and 1 week of endodontic treatment, patients' pain symptomatology was evaluated through a Visual Analog Scale (VAS) ranging from 0 to 10, in which 0 corresponds to no pain and 10 indicates extreme pain. In both workgroups, similar protocols were used for instrumentation with the Reciproc system (R40), irrigation with 2.5% sodium hypochlorite, and filling by the gutta-percha plastification technique, in which the CG did not use PDT, and the LG used PDT after the instrumentation sequence. After the visit, the patients were given a prescription for ibuprofen 400 mg to be taken every 6 h if they experienced pain.

Results:

The results of the study, analyzing the VAS, did not show any difference in pain symptoms between the groups at 24 h, 72 h, and 1 week (P > 0.05).

Conclusions:

It was concluded that there was no statistical difference between the groups.

INTRODUCTION

It can be stated that the unpredictable form of the apical internal anatomy[1] is the major obstacle in the search for cleaning and shaping, proposed by Schilder[2] with the objective of removing organic and inorganic material, besides the nonspecific elimination of microorganisms. The chemical mechanical preparation of the root canals until the early 1980s was performed using the apex/crown technique,[3] which could be responsible for postoperative pain symptomatology. From 1980, Marshall and Pappin[4] proposed a new concept of instrumentation called crown/down, using files for cervical and middle preparation, then advancing gradually toward the apex, gradually decreasing the diameter of the instruments. Several endodontic techniques and instruments were developed to improve the treatment of the root canal system. Reciproc is one of these systems and enables endodontic treatment with only one instrument.[5]

Photodynamic therapy (PDT) has been studied as a promising technique to eradicate oral pathogenic bacteria.[6] However, there are doubts about the actual antimicrobial influence of PDT during endodontic treatment in vivo, due to the complex internal anatomy of the root canals. The purpose of this prospective clinical study was to evaluate endodontic posttreatment pain, using Reciproc files, with or without PDT, on necrotic teeth. The null hypothesis tested was that there is no difference in the incidence of postoperative pain between the groups.

MATERIALS AND METHODS

This clinical research was approved by the Research Ethics Committee of the Dental Research Center (NP 2.332.600). All persons proposed to integrate this research accepted and signed an informed consent form. All treatments were performed by a single experienced endodontist, in a single session with final restoration.

Selection of patients

Forty patients, aged 18–76 years, were included in this study. The inclusion criteria were single-root teeth and a canal with a diagnosis of pulp necrosis, showing apical periodontitis visible on periapical radiography, without spontaneous painful symptoms, and that its apical anatomic diameter was equivalent to a K #20 file, according to the manufacturer for standardization of apical foramen instrumentation. The exclusion criteria were as follows: patients with any pain, patients with systemic problems that could alter tissue healing and repair process such as diabetes and autoimmune diseases, and patients who were taking analgesic, anti-inflammatory, and antibiotic medication at the time of the research.

Treatment protocol

Both groups

Local infiltrative anesthesia administered was 3.6 mL mepivacaine 2% 1:100.000 (DFL). After access surgery, initial irrigation with 2.5% sodium hypochlorite (NaOCl) and canal exploration with K #15 file (Dentsply Maillefer) to the working length (WL) was performed to neutralize the necrotic contents and avoid extravasation. The determination of the WL was established using a foraminal apical locator (NovApex, Forum Technologies, Rishon Le-Zion, Israel) with a K #15 file, using WL 0.0, for both the groups.

The biomechanical preparation of the middle and apical thirds occurred with the use of the electric motor VDW Silver Reciproc (VDW, Munich, Germany) and Reciproc files #40 (VDW, Munich, Germany), with three in-and-out movements until reaching the WL. Irrigation was performed with 2.5% NaOCl, and NaviTip 30G needle (Ultradent Products Inc., South Jordan, UT) with each withdrawal from the canal instrument and the debris from the Reciproc instrument were removed with sterile gauze.

The final irrigation was performed by intercalating three cycles of the 20 s of 2.5% NaOCl and 17% ethylenediaminetetraacetic acid (EDTA), using ultrasonic vibration at 3 mm below WL, with insertion E1 Irrisonic ultrasound insert (Santa Rosa de Viterbo, Brazil) for smear layer removal. After the passive ultrasonic irrigation cycle, the canals were irrigated with 3 mL of 2.5% NaOCl. The canals were dried with standardized Reciproc #40 absorbent paper tips.

Control group

Definitive seal was performed after chemical-mechanical preparation. Obturation was accomplished by the thermoplastic technique, using Mac Spadden condensor #50 (Dentsply Maillefer, Ballaigues, Switzerland), and R40 cones 0.5 mm below WL and endodontic cement AH Plus (Dentsply, Germany). After that, the gutta-percha cones were cut with Paiva condensers (Dentsply Maillefer, Ballaigues, Switzerland). The pulp chamber was cleaned with banana oil, and the teeth were sealed definitively with 2 mm of Coltosol (Vigodent, Rio de Janeiro, Brazil) and restoration of photopolymerizable composite resin.

Laser group

After drying the canals, methylene blue Chimiolux 5 (DMC, São Carlos, Brazil) was placed in the canal with the aid of the irrigation tip NaviTip 30G (Ultradent, Salt Lake City, USA). After 5 min of irrigation (preirradiation time), the low-intensity red laser (660 Nm) was applied for 90 s (320 J/cm²). Finally, the canals were irrigated with 3 mL of 2.5% NaOCl for the removal and neutralization of methylene blue. The obturation was performed in the same manner as in the control group (CG).

Evaluation of postoperative pain

All patients received a Visual Analog Scale (VAS) ranging from 0 to 10, in which 0 corresponds to no pain symptomatology and 10 indicates extreme pain. The patients were advised to evaluate the pain in three periods: 24 h, 72 h, and 7 days after the end of treatment. In case of pain, they were instructed to take ibuprofen 400 mg every 6 h.

Statistical analysis

Statistical analysis used the GraphPad Prism program, version 6.01 (OSB software, São Paulo, SP, Brazil) (descriptive and inferential analysis). The statistical treatment requires the use of nonparametric tests because it is an ordinal scale in scores and a post hoc test that allows two-to-two comparisons between the groups, in case of statistical significance (α = 0.05). Inferential analysis was performed using the Friedman test (comparison of experimental times) and Wilcoxon test (comparison of treatments).

RESULTS

Comparison between experimental times

The Friedman test, applied to different experimental times, revealed significant differences between 24 h and 7 days for both the laser group (LG) (P = 0.0020) and the CG (P = 0.0004). There were no differences between other experimental times (P > 0.05).

Comparison between treatments

For the inferential analysis of the sample, the Wilcoxon test was used to compare the treatments in the same experimental time. All experimental times were similar for the LG and CG (24 h: P = 0.280, 72 h: P = 0.154, and 7 days: P = 0.188). The descriptive analysis of pain data is presented in Table 1.

Table 1.

Median and amplitude of pain results in Visual Analog Scale

	Laser	Control
24 h	0.5 (0-5) A	1 (0-3) A
72 h	0.0 (0-9) AB	0 (0-5) AB
7 days	0.0 (0-2) B	0 (0-2) B

Equal letters do not present statistically significant differences

DISCUSSION

There was no statistically significant difference between the groups with conventional endodontic treatment and the use of antimicrobial PDT. Therefore, the null hypothesis was accepted.

For the calculation of the samples, the present study was based on some reviews, such as Ehsani et al.,[7] who evaluated postendodontic pain using VAS in groups with n = 20. In this study, the standardization of the sample was based on the work of Silva et al.[8] and Cruz Junior et al.[9] They selected uniradicular teeth, with a single canal, visible apical periodontitis in the periapical radiographic examination with bone rarefaction >2 mm[10] and asymptomatic.[11]

It is noteworthy that the ideal sample would be to evaluate the symptomatology after endodontic treatment in a single group of dental elements. However, Kherlakian et al.[11] evaluated 210 posterior teeth, 121 maxillaries and 89 mandibular teeth, 38 premolars, and 172 molars. Different dental groups, even though they have similar characteristics, have different innervation and vascularization, which could influence the result. Based on the principles described by Yared,[12] the Reciproc^® R40 instrument (VDW) was used after manual file #20 was introduced to the WL. The instrumentation and the irrigation protocol used were based on the work of Cruz Junior et al.,[9] ending with passive ultrasonic irrigation.[13]

Methylene blue 0.005% (Chimiolux, DMC^®) was placed into the canal for 5 min before using the red laser (660 Nm/90s - DMC®).[14] The position of the fiber-optic tip (DMC^®) within the canal during irradiation was 1 mm below the root apex.[14]

Several authors[15,16,17] have used different combinations of these parameters with positive results, most of them in vitro, and only two of them performed in vivo showed the effect of increased disinfection assisted by PDT.[14]

Evaluation of painful symptoms after endodontic treatment was performed using the VAS from 0 to 10, in which 0 is equivalent to no pain and 10 indicates extreme pain. According to VAS values, pain levels were classified as without pain (0), mild pain (1–3), moderate pain (4–7), or severe pain (8–10). Kherlakian et al.[11] used a horizontal line measuring 100 mm in length according to four classes: no pain or level 1 (0–24 mm), mild pain or level 2 (25–49 mm), moderate pain or level 3 (50–74 mm), and severe pain or level 4 (75–100 mm). Pak and White[18] questioned the VAS since most of the studies that use this scale report a 100% prevalence since even the smallest discomfort is recorded with a pain score higher than zero. The pain sensitivity is subjective and depends on the pain threshold of each patient. It is essential to prepare questionnaires that can be well understood by the patients and easily interpreted by the researchers.[19]

All volunteers received the postoperative pain questionnaire that occurred at three different times: within 24 h, 72 h,[17] and 1 week after canal filling.[20]

Cruz Junior et al.[9] compared postoperative pain with or without foraminal enlargement. Only one patient in the LG required medication, due to a flare-up. Diverging from the clinical study was performed by Kherlakian et al.,[11] where the frequency of intake of ibuprofen 400 mg tablet was 24.30% on the 1^st day, 5.70% on the 2^nd day, and 1.40% on the 3^rd and 7^th days. There was a regression of painful symptomatology over time. The pain was higher in the first 24 h, with a significant reduction in subsequent observation times of 48 h, 72 h, and 7 days.[9,11] Similar results were described by Pak and White[18] in which the incidence of pain was 40%, declining sharply, particularly during the first 2 days, reaching 11% at 7 days. The prevalence of mild pain or the absence of pain was similar to those reported in other studies.[8,9]

Several studies using antimicrobial PDT during endodontic treatment are available in the literature. Either, in vivo,[14] ex vivo,[15] or in vitro[21] studies, all of them with the methodology evaluation of reduction of microorganisms, before and after the use of PDT.. However, no study was found comparing the pain symptomatology, using PDT. Numerous in vitro studies demonstrate the antimicrobial potential of PDT, especially about Enterococcus faecalis in the most various parameters. In the CG, a final irrigation was performed with 2.5% NaOCl and 17% EDTA, employing ultrasonic vibration three times of 20 s, as well as in the PDT group. Therefore, the irrigation process was very consistent, in agreement with the available literature.[8,9] The PDT, according to the results obtained, did not show an improvement in postoperative pain. This can be explained by the fact that the teeth used in this study have a single straight canal which allowed the complete cleaning and modeling by endodontic instruments. There was no need to complement the disinfection with the use of PDT as an adjuvant to conventional endodontic treatment.

However, more studies are needed to verify the antimicrobial potential of PDT in vivo endodontic therapy and a higher number of cases with E. faecalis to reliably verify its susceptibility to PDT.

Thus, randomized clinical trials using PDT should be performed to evaluate the postoperative pain symptomatology and the periapical repair process, through clinical and radiographic longitudinal controls.

CONCLUSIONS

Based on the results of this study, it was concluded that the pain between the groups was equivalent.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.