The diurnal variation in the flow of saliva and hence the composition of saliva is an established fact. Consumption of acidic and sweetened food and beverage is known to reduce the salivary pH and some of them reduce it to critical pH levels and result in structural damage to the hard tissues of the tooth.

The purpose of this study is to ascertain the effect of the select commercially available test carbonated drink containing sugar on the salivary pH and assess the buffering capacity of the saliva with or without various intervention measures following the exposure to the test carbonated drink at different time intervals.

There are substantial existing evidences that there is diurnal variation in the flow of saliva and hence the composition of saliva. The average of normal pH of saliva is reported to be 6.8. Consumption of acidic and sweetened food and beverage is known to reduce the salivary pH and some of them reduce it to critical pH levels and result in structural damage to the hard tissues of the tooth. Such damages can be prevented by maintaining the salivary pH within optimal range by using oral hygiene measures.

The purpose of this study is to ascertain the effect of the select commercially available test carbonated drink containing sugar on the salivary pH and assess the buffering capacity of the saliva with or without various intervention measures following the exposure to the test carbonated drink at different time intervals.

Aims and objectives:

1. To measure the pH of saliva post-exposure to commercially available test carbonated drink after 5, 15, 30, 45 and 60 minutes.
2. To measure the pH of saliva at 15, 30 and 45 minutes after using a tap water gargle as a buffering agent in those subjects who had prior exposure to commercially available test carbonated drink 15 minutes ago.
3. To measure the pH of saliva at 15, 30 and 45 minutes after using a 0.2% Chlorhexidine mouth rinse as a buffering agent in those subjects who had prior exposure to commercially available test carbonated drink 15 minutes ago.
4. To measure the pH of saliva at 15, 30 and 45 minutes after chewing Orbit® gum as a buffering agent in those subjects who had prior exposure to commercially available test carbonated drink 15 minutes ago
5. To measure the pH of saliva at 15, 30 and 45 minutes after brushing with fluoridated tooth paste and soft brush as a buffering agent in those subjects who had prior exposure to commercially available test carbonated drink 15 minutes ago
6. To measure the pH of saliva at 15, 30 and 45 minutes after gargling with 1% solution of baking soda as a buffering agent in those subjects who had prior exposure to commercially available test carbonated drink 15 minutes ago
7. To compare the efficacy of buffering agents on the pH of saliva at 15, 30, 45 minutes post intervention in subjects who have had the commercially available test carbonated drink 15 min prior to the a specific intervention, with the pH of saliva recorded in the same subjects at the same time periods when no intervention with any buffering agent was carried out after having the commercially available test carbonated drink.
8. To compare the pH of saliva recorded in the subjects at 15, 30, 45 minutes time periods when they used an intervention of gargle with tap water, with that recorded when they used mouth rinse of 0.2% Chlorhexidine, with that recorded when they brushed with soft brush and fluoridated tooth paste, with that recorded when they gargled with 1% baking soda solution and with that recorded when they chewed Orbit® chewing gum (15 minutes after using the commercially available test carbonated drink)

Materials and Methods:

30 volunteers in the age group of 18- 30 year with healthy oral cavities will be selected.

Subjects with a history of any chronic medical illness, history of allergy, intake of drugs in the last 8 weeks, history of gastritis, bulimia will be excluded. Subjects with a DMFT score of more than 2 and Loe and Sillness Index of more than 0 will be excluded. Individuals who have and are currently undergoing orthodontic treatment will not be included in the study. Individuals who smoke or chew tobacco will not be included in the study sample. An informed consent for the research will be obtained from all the subjects who have volunteered for the study.

The trial will be conducted as per the guidelines in the WHO-Handbook for Good Clinical Practice and the research protocol is approved by the Institutional Ethics Committee of the college.

The test carbonated drink that will be selected is Coco Cola®. The various buffering agents that will be used are:

1. 0.2% Chlorhexidine mouth wash (Rexidine®, Indoco Remidies Ltd, Mumbai, India)- 10 ml solution swish for 60 sec and spit
2. Tap water- 10ml swish for 60 sec and spit
3. Brushing with fluoridated (Colgate Total®, Colgate-Palmolive Company, Mumbai, India) tooth paste- 2min using soft brush
4. Chewing polyol containing gum (Orbit®, WrigleyCompany)- chew for 5 minutes and spit
5. Freshly prepared Sodium bicarbonate (baking soda) 1% w/v solution- swish for 60 sec and spit The observer who will be recording the salivary pH will remain blinded about the samples and buffering agent used.

The select individuals will be instructed to not use any mouth wash as part of oral hygiene regimen on test day and not consume any food or beverage for 2 hours prior to the collection of baseline sample of saliva at 10 AM on the test day. The select group of 30 individuals will be given a sample of 100 ml of the test carbonated drink after recording their baseline salivary pH (0 min). They will be asked to sip, swish and swallow the drink within 2 minutes. After the exposure, salivary samples will be collected at 5 min and 15 min intervals for assessment of pH. Fifteen minutes after the exposure (consumption of test drink), the individuals will be asked to use one of the intervention methods included in this study. The salivary samples will be collected after 15, 30 and 45 minutes interval after the intervention. (i.e. 30, 45 and 60 minutes post exposure to the test drink respectively) The same protocol will be repeated using each intervention methods included in this study after a wash out period of minimum of 3 days. The protocol will be repeated on the study sample without any intervention following the exposure to the test soft drinks as a control.

Measurement of salivary pH will be done using a portable PH-035 Digital pH meter with automatic temperature compensation, to the accuracy of 0.1 and the machine will be calibrated on the morning of every test day and after 60 uses during the test day using Aquasol® pH calibration solutions with pH 4, 7 and 10.

Inclusion Criteria:

• subjects in the age group of 18 to 30 years.
• subjects with a DMFT index score of less than 2.
• subjects with Loe and Silness index score of 0.
• subjects willing to volunteer for the study.
• subjects who are available for the whole study period of 4 months.

Exclusion Criteria:

• subjects with history of gastritis and bulimia.
• subjects with chronic medical illness.
• subjects with history of allergy.
• subjects with history of drug intake for last 8 weeks.
• subjects who smoke or chew tobacco.

only primary investigator will know the intervention done by the subject. The outcome investigator(assessor) will be unaware (blinded) to which intervention the subject is undertaken.