Comparative evaluation of low level laser therapy in post endodontic pain management - A quasi experimental trial

Introduction

Laser is defined as a monochromatic, collimated, coherent, and intense beam of light produced by stimulated emission of radiation of a light source.¹ Low level lasers are also called soft or cold lasers. These lasers produce non-thermal effects on tissues by a phenomenon known as Photobiostimulation. It works on a Power range between 0.005 to 0.5 Watt and a power Density lesser than 670mW/cm2. It uses a Wavelength between 600 and 1000 nm which falls in the near infra-red range. Single visit endodontics overcomes various disadvantages of endodontics in multiple visits such as increased number of appointments and there is a risk of inter appointment leakage through the temporary restoration.²

Analgesics are given for the relief of postendodontic pain out of which the commonest are Nonsteroidal anti inflammatory drugs.³ However, administration of Non Steroidal AntiInflammatory Drugs is related to various side effects.

Photobiostimulation , is used in dentistry since fifty years. Due to its neuron-regenerative effect and anti-inflammatory, shows an analgesic effect.⁵ LLLT causes a delay in the initiation of pain and reduces the severity and also ,duration of pain with limited side effects.⁶

Hence, the aim of this clinical trial is to evaluate the efficacy of administration of pre-operative and intra-operative low level laser therapy in post endodontic pain management in subjects with symptomatic apical periodontitis post single visit endodontics.

Objectives:

To evaluate and to compare the effect of preoperative Low Level Laser Therapy in subjects with symptomatic apical periodontitis in their mandibular second premolar post single visit endodontic treatment.

Materials and Methods

Eligibility criteria for participants Inclusion criteria:-

1. Subjects of a of 20-60 years of age

2. Subjects with symptomatic apical periodontitis in their mandibular second premolars with one root canal and suitable for single visit root canal therapy.

3. Subjects who can read and write.

Methodolog

Thirty subjects with symptomatic apical periodontitis in their lower premolars were arbitrarily split by a software into three groups A,B,C. A randomization scheme was formed through a website (www. randomizer.org).A blinded researcher performed the randomization , and without the knowledge of the clinician who was performing the treatment procedure. Patient compliance of laser was evaluated for all the subjects. Informed consent was taken from every patient.

Group A included 10 subjects were administered low level laser 5 minutes prior to the procedure at the apical end of tooth through the buccal mucosa and into the canal after root canal preparation upto the working length.

Group B consisted of 10 subjects were given ibuprofen 600 mg half an hour before the procedure and administered low level laser 5 minutes before the procedure at the apex of tooth through the buccal mucosa and into the canal after pulp space preparation.

Group C included 10 subjects who were treated with single visit endodontics and was not given laser/analgesic pre-operatively. (control group)

Endodontic Treatment Specifications

Administration of Local Anesthesia was done for all the patients. The Root Canal Treatment was performed in a single visit under rubber dam isolation, using 5.25% Sodium Hypochlorite as an irrigant, Endometrices was determined using woodpecker apex locator and confirmed using radiograph. Root canal instrumentation was done using Protaper Rotary File system.Group Low Level Laser Therapy was given to Groups A and B post root canal instrumentation. Single cone obturation was done for all the groups. The temporary restoration given was cavit.

Subjects of all the groups were prescribed analgesics.

Laser Specifications

250mw of Diode laser (Figure 1) for 60 seconds at tooth’s apical end through the buccal mucosa in non contact mode(Figure 2) and into the pulp space post root canal instrumentation till the determined endometrices for 30 seconds ( Figure 3). Intensity of pain after the root canal treatment was noted down on a visual analog scale by 4hr, 8hr, 12 hour, 24 hour interval. The visual analog scale was provided to all the subjects, and was instructed to mark the pain score at the mentioned time intervals.

Results

The difference in pain reduction within the groups that is the laser group and the laser analgesic combination group at different time intervals that is 4 hr, 8 hr, 12 hr and 24 hr time intervals was not significant statistically.

Within the control group the pain scores were maximum at 12 hour and 24 hour and minimum at 4 hour and 8 hour. This difference is significant statistically.

Among the three groups, the laser group and the laser analgesic combination group had more pain reduction than the control group and it was significant.

The laser group and the laser analgesic combination group at 4 hour and 24hour showed no statistical significance.

The laser group depicted lesser analgesia at the time interval 8 hour and 12 hour than the laser analgesic combination group and this difference was significant statistically.

Discussion

The occurrence and the intensity of pain after single-visit endodontics is more.⁷ Post-obturation pain can be related to several factors including infection, preoperative pain, and physical and chemical damage to periapical tissues.⁸ It causes hyperalgesia due to peripheral and central mechanisms caused by the activation of sensitive nociceptors and the release of inflammatory mediators such as prostaglandins, leukotrienes, bradykinin, and serotonin.⁹ NSAIDs are prescribed for post endodontic pain management.

A wide array of adverse effects follow the administration of Non Steroidal Anti-Inflamatory Drugs such as altered renal function, variation in blood pressure, injury to the hepatic system and inhibition of platelet resulting in increased bleeding and gastrointestinal effects.⁵

In a clinical trial that involved surgical removal of impacted third molars, preoperative irradiation of Low Level Laser prior and after the extraction had an analgesic effect and it was connected with a lower necessity of analgesics on the first day post treatment.¹

Management of pain after endodontic treatment has been done using LLLT. However, the presesented clinical trial is the first study in which pre-operative laser is given for the management of post-operative pain in endodontics.

LLLT exhibits bio-stimulatory effect, seldom causes an increase in the temperature of the irradiated tissue greater than 36.5°C. The precise biophysics of the action of this Low Level Laser is not well understood. The reported reasons for the pain relief caused by this therapy can be exaplaine through alteration in the overall cell redox potential towards greater oxidation by increasing unstable oxygen molecules (ROS) and decreasing reactive nitrogen species (RNS)¹⁰. LLLT also increases the production of endorphin production¹¹, causes activation of microcirculation, nerve cell stimulation and respiration of lymphocyte. The pain decreasing effect of LLLT can also be understood through the stabilization of membrane potentials¹², release of neurotransmitters in the inflammatory tissue, substance P elongation and reduction of CGRP-rich (Calcitonin Gene-Related Peptide) neuritis.¹³

In this clinical trial, the groups involving administration of LLLT showed significantly more pain reduction than the control group after endodontic therapy at all the observed time intervals.

In a previous study on the analgesic effect of photobiostimulation in Single-Visit Endodontics, pain after the treatment was significantly reduced in Laser group at time intervals 4hr, 8hr, 12hr, and 48 hr compared to the placebo group and this is in concurrence with this study.¹⁴

In another study, photobiostimulation was effective in reducing postendodontic therapy pain at 4hr, 8hr, 12hr, and 48 hr post molar endodontic therapy which is similar to this study.¹⁵

In the present study, there was no significant difference in pain reduction between the laser groups with and without analgesics at 4 hour and 24hour suggesting that administration of LLLT prior to the treatment could be an alternative to NSAIDs. However more studies are to be done to establish low level laser therapy as a nonpharmocological method of pain management post single visit endodontics.

Conclusion

In this clinical study, Photobiostimulation alone and with analgesics has shown statistically significant reduction in pain and hence was productively used in the management of pain after endodontic treatment. More studies with photobiostimulation in the arena of endodontics will reveal the chances of success of this approach for the reduction of postendodontic treatment pain as an alternative to the regular pharmacological approach.