Tooth Decay: Causes and Prevention

The human system is a complex machine which consists of various vital organs and structures. The oral cavity is one such important area which is regarded as a ‘gateway for systemic health,’ says DR. SYED PARVEZ ALI


The human oral cavity consist of about 32 teeth out of which four teeth are vestigale, which means to say that their presence do not serve any particular purpose.

Types of human teeth

The human teeth are of various types and includes the following:

1. Incisors: The incisor teeth which are the front teeth that help in cutting up food into small particles.

2. Canines: The canines are the very sharp and prominent teeth that take part in shearing the food. The canines are regarded as the corner-stones of the dental arch. Absence of canines in the dental arch produces a serious cosmetic deformity by giving the dental arch a squarish form and a flat-faced appearance.

3. Molars: Molars are the teeth which are the largest and the strongest among all the teeth. These play a very important role in grinding the food.

4. Premolars: Premolars are the teeth which are present below the canines and the molars.

Parts of the human tooth

The normal adult has about 32 teeth while a child has only about 20 teeth before the age of six. The teeth consist of various parts all of which together constitute the tooth as a whole. These parts are as follows:

1. Enamel: It is the outermost layer of the tooth which appears whitish to yellowish or greyish in colour. It is the hardest tissue in the human body, and is even stronger than the human bone. Enamel is the only tissue in the teeth which has the capacity to bear the chewing forces.

2. Dentin: This tissue is present below the enamel, and is yellowish in colour. It consists of small and minute fluid-filled canals which help in absorbing and regulating thermal changes. The human oral cavity is subjected to various thermal changes during food intake that varies from hot coffee and tea taken at a temperature of +55ºc to cold drinks to ice-cream which are at – 5ºC. Both the extremes of temperature changes are harmful for the survival of the tooth. But by regulating both the extremes of temperature changes which are detrimental to the tooth, Dentin improves the survival rate of the human tooth. It also plays an additional role of acting as a shock absorber by taking up all the chewing forces to which a tooth is subjected during chewing thereby preventing fracture of the tooth.

3. Pulp: It is the inner most layer of the tooth which carries nerves and blood vessels.

Stages of tooth decay

When the decay is present within the Enamel (or the outer most layer of tooth), decay does not cause any symptom of pain. Filling the tooth at this stage not only saves money but will also prevent further decay which can later cause pain. When the decay process reaches the Dentin part of the tooth, it causes a little bit of sensitivity, but still does not cause any serious problems. Filling the tooth at this stage also saves time and efforts.

If the decay process is deeper and extends through the Enamel, Dentin and even the Pulp (which is a Neuro-Vascular tissue), severe pain will occur. The infection spreads rapidly along the Pulp tissue and thereby leads to decay of the pulp tissues and pus formation. If the infection remains in the tooth for a long period of time, it leads to the formation of a swelling called an abscess which contains the pus. Once the tooth has reached this stage of decay, it will have to be either pulled out, or Root Canal Therapy (RCT) has to be done.

The tooth has to be abscessed completely before deciding the treatment. This is especially needed while planning RCT treatment where, before starting the procedure, the amount of tissue destruction and its severity must be determined at the outset. If it is not done properly, the RCT can miserably fail.

Causes of tooth decay

1. Excess intake of sugars.

2. Type and content of food. Foods that are coarse and easily cleansable do not cause tooth decay. But food stuffs that are sticky and which remain on the tooth for a long time pre-disposes the tooth for caries.

3. Poor oral hygiene maintenance.

4. Dry mouth called as Xerostomia which can be due to Diabetes, radiation therapy for head and neck Cancers, intake of drugs like sleeping pills etc.


1. Visit your dentist every three months.

2. Good hygiene maintenance

3. Restrict intake of food very rich in Carbohydrates. Foods rich in Protein and Fat do not cause tooth decay. If at all Carbohydrates in taken in any form like bakery products, chocolates, chips, snacks etc., make sure that you gargle your mouth with water to flush out the sugary contents.

4. Brush your teeth twice everyday.

5. You can also do warm water gargling or use mouth rinse solutions to keep the bad odour at bay, and also to keep the teeth clean.

6. If the tooth decay is in the initial stage, get the appropriate fillings done.

7. Dental floss can be used in those patients who have crowding of the teeth to promote dental care.



1. Text book of Oral and Dental Histology (Ten Cate)

2. Text book of Oral Pathology (Shapfer)

3. Text book of conservative Dentistry (Stedreains)

4. Text book of Pedodontics (Shobha Tendon )


[The writer is a dentist doing his post graduation (MDS) in Radiology and Oral Health in Bangalore]

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