Determination of Effectiveness of Photobiomodulation in the Treatment of Oral Submucous Fibrosis.

Context: Oral submucous fibrosis (OSMF) is chronic, scarring disease of the oral cavity. Cytokines and growth factors produced by inflammatory cells play a major role in its pathogenesis. Low-level laser therapy (LLLT) application, which has an anti-inflammatory, was used to determine the improvement in mouth opening. Aims: The aim of the study is to evaluate the effectiveness of laser photobiomodulation (PBM) in OSMF treatment. Materials and
Methods: Thirty patients who were diagnosed with OSMF after obtaining consent form and ethical clearance were included. LLLT was applied for 4 cycles for 15 s each in the left and right buccal mucosa. Therapy was done on day 0, 3, 7, and 15 and measurements were done immediately after each LLLT application. Patients were recalled after 1, 3, and 6 months from the commencement of the therapy for follow-up measurements.
Results: The mean increase in mouth opening following application of LLLT from day 0 to day 15 was 9.91 ± 3.34, and day 1-6 months was 14.29 ± 6.82, which was statistically significant. Conclusions: The study shows significant improvements in the mouth opening of the OSMF patient during treatment and postoperatively. Thus, our study confirms LLLT can be used as one of the modality in OSMF management. Copyright:

INTRODUCTION

Oral submucous fibrosis (OSMF) is a scarring, chronic high-risk precancerous condition of the oral mucosa, pharynx, and upper digestive tract, characterized by progressive inability to open the mouth, epithelial atrophy, and development of fibrous bands in the buccal and labial mucosa affecting betel quid chewers and habitual smokers.[1]

OSMF is seen predominantly in Asian countries with the highest prevalence in India, the prevalence has increased from 0.03% to 6.42% in the past 5 decades.[23]

Areca nut, tobacco, iron and zinc deficiencies, chilies, lime, immunological disorders, and collagen disorders are some of the etiologies mentioned in literature.[4]

The involved pathogenesis is an inflammatory reaction in the sub epithelium and mucosal fibrosis. Cytokines (interleukin-6 and Interferon-alpha) and growth factors produced by activated inflammatory cells produce growth factor that promotes fibrosis and thus there is increase in collagen synthesis and decrease in collagen degradation.[5]

Cessation of the habit is adequate to treat at early stages of the disease but surgery, physical therapy, or combination of these have been used for moderate-to-severe cases. However, the results of these management methods have been unsatisfactory, expensive, invasive, and sometimes unreliable. Hence, there is a need for newer strategies for the treatment of OSMF.

”LASER” the word stands for “Light Amplification by Stimulated Emission of Radiation”. The present study takes the advantage of soft tissue laser or low level laser (LLL) for its treatment. LLL interacts with cells and tissues inducing a modulatory effect on its biochemical processes. At an appropriate dose, LASER causes stimulation of lymphocytes, activation of mast cells, increases mitochondrial adenosine triphosphate (ATP) production and causes reduction of pro-inflammmatory cytokines through a process called “Photobiomodulation” (PBM).[6] This leads to its anti-inflammatory, analgesic and anti-edematous propertiesApart from the above advantages LASERS are cost-effective, non-invasive, and available as portable device.

The present study was conducted based on the above advantages and the fact that there is no available scientific evidence-based studies demonstrating the effectiveness of PBM in the treatment of OSMF.

METHODS

Ethics

Institutional Ethical Committee clearance was obtained with Ref No: KIMS/IEC/D18/2018 at Kempegowda Institute of Medical Sciences. Patients were explained about the procedure and its effect in the patient's own/understandable language and informed consent was obtained.

Method of collection of data

Sample size estimation was done using the G power software v. 3.1.9.2

The P < 0.05 was set as significant level.

Methodology

Clinical examination

Thirty clinically determined OSMF cases with reduced mouth opening secondary to chewing tobacco/areca nut within the age group of 30–60 years reporting to Outpatient department were included.

Patients already undergoing treatment for OSMF, with premalignant lesions such as leukoplakia, erythroplakia, severe OSMF, TMJ disorders, pericoronitis medical conditions like epilepsy, coagulation disorders, thyroid disorders, patients undergoing radiotherapy were excluded from the study.

Preprocedural evaluation was conducted: Each patient was clinically examined for mouth opening of mouth using Vernier caliper.

The current study LASER unit utilized in the was BTL-5000 Series. The unit was set at an output power of unit was set at 100 mW and a wavelength of 830 nm. The patient was seated comfortably and Protective eyewear was worn by the patient and dentist. The treatment was conducted in 4 sittings, i.e., on day zero, three, seven, and fifteen.

LLL(low level Laser) was applied on the lesion in a continuous circular motion (taking care to cover the entireity of the lesion) for 15 seconds each with an interval of 20-30 seconds between each application for a total treatment time of 3 minutes. Mouth opening was evaluated and recorded immediately post LASER application at days 0, 3, 7, 15, respectively. The patients were asked to quit using arecanut/tobacco and to refrain from using any other medicine/treatment for OSMF.

Patients were recalled 1 month, 3 months, and 6 months from the initiation of the therapy and evaluated for any posttreatment change in mouth opening.

Statistical analysis

Statistical Package for Social Sciences for Windows Version 22.0 Released 2013. Armonk, NY: IBM Corp., was used to perform statistical analyses.

RESULTS

The comparison of mean mouth opening (in mm) between different time interval during the treatment period using repeated measures of ANOVA test. The mean and standard deviation (SD) on day 0 was 27.85 ± 5.95, on day 3 was 28.42 ± 5.99, on day 7 was 29.4 ± 6.0, on day 15 was 30.5 ± 6.31 with a P < 0.001 (statistically significant). Moreover, during posttreatment using repeated ANOVA test, the mean and SD on 1st month was 30.75 ± 6.07, 3rd month was 31.08 ± 6.05, 6th month was 31.62 ± 6.03 showed statistically significant P (< 0.001).

The mean difference in mouth opening between the different time interval by using Bonferroni's post hoc analysis by multiple comparison revealed statistical significant values < 0.001, with 95% confidence interval (CI) between day 0 and day 3, 7, 15, day 3 and 7, 15, and day 7 and day 15 [Table 1].

Table 1

Multiple comparison of mean difference in mouth opening between time intervals during different treatment periods using Bonferroni’s post hoc test

Time (I)	Time (J)	Mean difference (I−J)	95% CI for the difference		P
			Lower	Upper
Day 0	Day 3	−0.57	−0.96	−0.18	0.002*
	Day 7	−1.63	−2.13	−1.14	<0.001*
	Day 15	−2.70	−3.22	−2.18	<0.001*
Day 3	Day 7	−1.07	−1.56	−0.57	<0.001*
	Day 15	−2.13	−2.73	−1.54	<0.001*
Day 7	Day 15	−1.07	−1.60	−0.53	<0.001*

*Significant statistically. CI: Confidence interval

Further, a comparison of multiple mean differences in mouth opening (in mm) between posttreatment periods were -0.33 between 1st and 3rd month, −0.87 between 1st and 6th month, −0.53 3rd and 6th month. The above values were statistically significant with a 95% CI [Table 2].

Table 2

Multiple comparison of mean difference in mouth opening between time intervals during post treatment periods using Bonferroni’s post hoc test

Time (I)	Time (J)	Mean difference (I−J)	95% CI for the difference		P
			Lower	Upper
1 month	3 months	−0.33	−0.53	−0.14	<0.001*
	6 months	−0.87	−1.11	−0.62	<0.001*
3 months	6 months	−0.53	−0.73	−0.34	<0.001*

*Significant statistically. CI: Confidence interval

Descriptive for mean percentage increase in mouth opening at different time intervals among study subjects showed mean and SD from day 0 to day 15 as 9.91 ± 3.34, 1st month to 6th month as 12.62 ± 5.10, and day 0–6th month as 14.29 ± 6.82 with minimum mouth opening was 2.7% to maximum 15.2% from day 0 to day 15, minimum mouth opening of 3.1% to maximum of 29.6% from 1 month to 6 month, minimum mouth opening of 3.2% to maximum 40.0% from day 0 to 6 month.

DISCUSSION

OSMF has multifactorial etiopathogenesis; the main causative agent is chewing arecanut with any formulation. Other contributing risk factor includes tobacco chewing, intake of chilies, low level vitamin, copper level in food, genetics, lower level of serum protein, and anemia leading to malnutrition.

Several studies were done that included drugs such as steroids, antioxidant, fibrinolytic enzymes, anti-ischemic agents, vasodilators, nutritional supplements, antifibrotic agents, and biogenic stimulants which showed variable results. These drugs exhibited relief of symptoms such as burning sensation ulceration and stiffness reduction. However, the improvement in mouth opening was less demonstrated in any of the above.[6]

LASER is a collimated monochromatic and coherent beam. It is divided into two types, high-level LASER and LLL. High level laser has the cutting effect hence used in bloodless surgeries, etc., LLL has the photobiomodulatory effect.

The bio stimulatory or inhibitory effects of LLL are governed by Arndt–Schulz law. The law states that strong stimuli will inhibit physiological activity and low doses will increase physiological process. For LLLT, the output power ranges from 50 to 500 mW, wavelength ranging from 630 to 980 nm which is in the red and near-infrared of the electromagnetic spectrum. LLL produces this effect within the tissue without causing temperature elevation. This therapy has been referred as biomodulation/biostimulation of LASER, which also known as therapeutic LASER.[7]

The LLL acts on cells through cytochrome C oxidase (primary photoacceptor), which is the terminal enzyme in electron transport chain. Mitochondrial membrane potential is increased when LASER is absorbed. This leads to increased energy availability and signal transduction due to release of ATP and reactive oxygen species.

This biochemical and molecular process interaction with cell causes reduction of pro-inflammatory cytokines and leads to anti-inflammatory and analgesic properties of LLL.[8]

Hence, this study was led to determine the effectiveness of LLLT in mouth opening of OSMF patients.

In our study, we analyzed the mouth opening during treatment and posttreatment at 1 month, 3 months and 6 month follow up. After the photobiomodulatory effect, there was significant improvement in mouth opening on day 3, day 7and day 15, alike to the study done by Singh et al., where the opening of mouth and burning sensation was assessed in which it showed results after application of LLLT.[9]

Only few in vivo and in vitro studies were done to detect the effectiveness of LLLT on fibrosis of the OSMF patient. An in vitro study was done by Yeh MC et al., revealed that after the application of LLLT, arecoline-mediated fibrotic marker genes were inhibited through the Cyclic Adenosine Monophosphate (cAMP) signaling pathway.[10]

A case report was published in which OSMF patient was diagnosed and was treated with LLLT which showed progress in opening of mouth and decrease in burning.[11]

An in vitro study done by Lee Y et al., to evaluate the inhibition of fibrosis by the combined effect of LLLT and phloroglucinol. The results revealed that the combined effect can be used in the inhibition of fibrosis.

To the best of our knowledge, only few in vivo studies have been piloted to prove the effectiveness of the LASER PBM in the therapy of OSMF patient. Results of our study proved to be effective during and posttreatment.

Limitation and future prospects

The majority of patient in our study were males with age: ranging between 30 and 50 years. Only mild – to- moderate-severe cases of OSMF were evaluated on differences in mouth opening which is only one of the clinical features of OSMF. LLLTs can also be applied to other clinical features like burning sensation this study can be considered a forerunner for future studies that could include other features with large sample size and equal gender.

CONCLUSIONS

LLLT is effective against inflammation and pain. The study showed that mean maximum increase in mouth opening from day 0 to 6 month was 40.0% which is considerable and statistically significant. The above translates to significant improvement in function and quality of life for patients with OSMF. Hence, we conclude that LLL can be used as a reliable treatment modality in OSMF management.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.