Orthodontic pain is one of the leading causes of discontinuing orthodontic treatment. It may be felt not only during the time of separator insertion but also throughout the course of the treatment and during debonding. Tooth movement leads to vascular compression and ischemia, leading to the release of local inflammatory mediators, such as prostaglandins and bradykinins and cytokines. Bradykinin and prostaglandin bind to sensory endings to generate painful sensations causing orthodontic pain.

Previous studies have shown that pain peaks at 24 hrs. and subside by 7 days. There are two methods of relieving pain – pharmacological and non-pharmacological. Most commonly, NSAIDs are prescribed by dentists to relieve the pain. These drugs not only cause disturbance in the bone remodeling process but also have various adverse systematic effects such as allergy, bleeding disorders, gastric ulceration, renal insufficiency, asthma and hypertension. This makes it important to consider non-pharmacological methods for relieving pain.

Various non-pharmacological methods include Transcutaneous Electrical Nerve Stimulation, Low-Level Laser Therapy, mechanical approaches such as vibrations and chewing gums, behavioral approach and gene therapy. But many of these methods require special devices such as a vibrational device or TENS device, which are expensive and cannot be afforded by all. Chewing gum is emerging as a promising alternative method of relieving pain. It displaces the teeth temporarily when we chew on it and loosens the compressed periodontal areas including nerve fibres and occluded blood vessels, restoring blood flow to the area. This causes quicker removal of inflammatory mediators i.e. analgesic products and resolution of pain. It also stimulates salivary flow reducing the incidence of caries.

Non pharmacological methods of relieving pain are a step forward in reducing the dependency on drugs to reduce orthodontic pain. Chewing gum can be an excellent and cheap alternative if its effectiveness is proven.

Rationale of the study: -

Though there is enough evidence regarding the usage of chewing gum for relieving orthodontic pain, a lot of controversies still exists about its effectiveness. Following limitations were observed in the previous studies that might have affected the strength of the research:

1)     Pain perception differs between both the sexes and there are not enough studies where homogeneity in terms of the distribution of sex is maintained.

2)     Pain perception differs depending on age, gender, anxiety, stress and previous pain experience. This makes it necessary to establish a baseline prior to the study so that the distribution of subjects can be done equally according to their pain pressure threshold. Pain threshold baseline data was not evaluated except the study done by Çelebi F.

3)     All the previous studies have taken a wide range of age to be observed. The bone density and pain perception vary with age.

4)     Cochrane review by Fleming PS et al shows that there is low-quality evidence due to bias in previous studies and inconsistent data regarding the relief of self-reported pain associated with the use of chewing gum. This is due to failure of patients to comply with instructions in case of home use of painkillers and chewing gum. Also, most studies allowed the use of adjunct analgesics, which interferes with the intervention.

5)     All the studies have taken an arbitrary time for testing the effectiveness of chewing gum as either 5, 10 or 20 mins.

6)     Most of the past studies were of shorter duration i.e., 2 weeks. Only single study is reported that was of 3 month duration.

1.     To evaluate orthodontic pain in young adult patients using visual analogue scale, measured immediately, after 6 hrs, 24 hrs., 48 hrs., 72 hrs and 7 days after the first appointment and the same for the subsequent three appointments.

2.     To evaluate orthodontic pain in young adult patients, after chewing gum for 20 mins post appointment, using visual analogue scale, measured  immediately, after  6 hrs, 24 hrs., 48 hrs., 72 hrs and 7 days after the first appointment and the same for the subsequent three appointments.

3.     To evaluate orthodontic pain in young adult patients, after using chewing gum for 30 mins post appointment, using visual analogue scale, measured immediately, after 6 hrs, 24 hrs., 48 hrs., 72 hrs and 7 days after the first appointment and the same for the subsequent three appointments.

I. Study design: This is a Randomized controlled trial with a sample size meeting inclusion criteria.

 II. Study setting: The study will be conducted in the Department of Orthodontics and Dentofacial Orthopedics. The study would be conducted abiding by all human ethical principles as per the guidelines of good clinical practice of the Indian Council of Medical Research will be followed.

 III. Study Population: Patients reporting to the Department of Orthodontics and Dentofacial Orthopedics for fixed orthodontic treatment and indicated for non-extraction treatment.

 IV. Sample size: Level of significance = 5%, Power = 90%, Type of test = two-sided

Formula of calculating sample size is:

F tests - ANOVA: Fixed effects, omnibus, one-way

Analysis: A priori: Compute required sample size

Input: Effect size f = 0.45

α err prob = 0.05

Power (1-β err prob) = 0.9

Number of groups = 3

Output: Noncentrality parameter λ = 13.36

Critical F = 3.142

Numerator df = 2

Denominator df = 63

Total sample size = 66

Actual power = 0.9019

Sample size for experimental study (outcome variable on ratio scale and testing null hypothesis.

A power analysis was established by G*Power version 3.0.1 (Franz Faul universitat , Kiel, Germany).

Total minimum calculated sample size of 66 rounded to final 75 samples (25 samples per group; total 3 groups) would yield 90% power to detect significant differences, with effect size of 0.45 and significance level at 0.05.

V. Sampling Technique: The sampling will be done randomly by simple random sampling.

 VI. Methods of selection of study subjects:

I)                Inclusion criteria:

1)     Patients between the ages of 18 to 24 years with full permanent dentition with or without third molars.

2)     Patients requiring full upper and lower fixed orthodontic treatment with no additional appliance (i.e., trans-palatal arch, headgear or elastics).

3)     Patients with no active periodontal disease or history of previous orthodontic treatment.

4)     Patients with no medical or mental problems/ disorders.

5)     Patients with mild to moderate crowding in both arches.

II)               Exclusion criteria:

1)     Patients requiring extraction of teeth for orthodontic purposes.

2)     Patients who use analgesic medications for medical causes like rheumatic arthritis, fractures, migraine.

3)     Patients who are allergic to sugar-free chewing gum.

4)     Patients with temporomandibular joint disorder like disc displacement, ankylosis.

III)             Subject withdrawal criteria:

1)     Patient is irregular in his appointments.

2)     Patients with breakage of brackets.

3)     Patient with pain threshold level less than the mean.

4)     Patients found to be allergic to sugar free chewing gum during the course of the study.

5)     Patients who took analgesics other than placebo.

 VII. Operational Definitions:

1.     Sugar free chewing gum - A conventional (unmedicated), commercial chewing gum that does not contain sugar and is usually sweetened with a sugar-like substitute.

2.     Placebo -it is a substance which is designed to have no therapeutic value.

3.     Visual analogue scale (VAS)- A measurement tool that attempts to measure a characteristic, perception or attitude that is believed to range across a continuum of values and that cannot easily be directly measured.

 VIII. Methods of measurements: -

Data will be obtained from the responses obtained by the visual analogue scale. A 100mm Visual Analogue Scale will be prepared to be distributed among the subjects. 75 patients within the age range of 18 to 24 will be selected. A detailed medical history will be taken for each patient followed by clinical examination. Before recruiting subjects, their pain pressure threshold will be measured using a pain pressure algometer and their baseline will be noted. The subjects will be informed about the details of study procedure and informed consent form will be obtained from them.

The subjects will be randomly divided into three groups of 25 samples each containing equal number of males and females allocated using computer generated random assignment program. Groups will be as follows :-

1.     Control

2.     Using chewing gum for 20 minutes

3.     Using chewing gum for 30 minutes

After routine orthodontic procedure, the subjects will be explained the procedure to fill the visual analogue scale and asked to fill it under supervision. All the subjects will be instructed to take the given tablet, a placebo, if the pain is beyond bearable. They will also be instructed not to take any other analgesic medications without consulting the investigator. the intervention group subjects will be provided with sugar free chewing gum at each visit. They will be asked to chew on the chewing gum for 20 and 30 mins respectively under supervision and then asked to again fill the VAS scale. All the subjects will be asked to fill the VAS at a fixed time (45 mins) after initial rating is done irrespective of the group they belong to.  All the intervention group subjects will be recalled on the 2^nd and 7^th day to repeat the same procedure and fill the VAS scale after it. All the subjects will also be instructed to make a note on the VAS scale at home at 6 hrs, 48hrs and 72 hrs after procedure is done. Telephone call reminders to fill the VAS scale will be done. This same procedure will be repeated in the subsequent three consecutive appointments.

VAS sheets will be collected back from the subjects at the end of the study.

 IX. Study instrument / Data collection tool: -

(1)  Pressure algometer

 X. Method of Data collection:-

The data will be collected based on the responses obtained by visual analogue scale. All subjects will be explained the procedure to fill the visual analogue scale in advance.

 XI. Data management and analysis procedure:-

Ordinal qualitative data will be obtained. Median will be recorded for descriptive statistics.

Statistical analysis will be performed using Statistical Package for Social science (SPSS) version 21 for Windows (SPSSInc Chicago, IL). Descriptive quantitative data will be expressed in mean and standard deviation respectively. Data normality will be checked by using Shapiro – Wilk test.

 XII. Data analysis plan and methods:-

Ordinal qualitative data obtained from responses to the VAS scale will be used for data analysis.  Confidence interval is set at 95% and probability of alpha error (level of significance) set at 5%. Power of the study set at 90%. Overall intergroup comparison among three groups will be done using Kruskal Wallis test followed by Mann Whitney U test for pairwise intergroup comparison between each groups.

 XIII. Research in AYUSH:

Not applicable

 XIV. Additional points for RCT :-

       i.          Randomization proposed- Computer generated random assignment program for allocation of males and females to equally distribute them into the three groups.

      ii.          Allocation concealment proposed- the randomized sequence will be generated and sealed in an opaque envelope by a second person. The investigator will open the envelope and give instructions to the patients according to the allocated group. Examiner, a person other than the investigator, will record the visual analogue scale scores after a fixed time.  

    iii.          Blinding proposed- single blinding is done. The investigator will be unaware of the VAS scores given by the patient.

 XV. Additional points for all Experimental studies:-