In the last part we discussed the basic introduction about dental caries , signs & symptoms . You can read the 1st part here by clicking DENTAL CARIES PART 1 INTRODUCTION & SYMPTOMS 

In this part we will be discussing about causes of dental caries & treatment options

Lets Have a Quick look on How Cavities are formed once again 


Tooth Consists of 3 major parts : ENAMEL , DENTIN , PULP 


Once the enamel is demineralized , caries spread to more sensitive Dentine & then to the Pulp that induces pain .


Many factors together are responsible for the spread of caries .

From the above flowchart it is clear that Two main factors contribute to tooth decay — bacteria and a diet high in sugar and starch. 

The mouth is colonized by 200 to 300 bacterial species, but only a limited number of these species participate in dental decay (caries) or periodontal disease.

These particular bacterias have high affinity for starch & sugar . These bacteria combine with food and saliva to form a sticky substance called plaque that attaches to teeth. Plaque is sticky and sticks to the tooth if not removed by regular brushing .

The bacteria ferments the starch to produce acids that dissolve the tooth structure . Dental decay is due to the irreversible solubilization of tooth mineral by acid produced by certain bacteria that adhere to the tooth surface in bacterial communities known as dental plaque.

Bacteria Responsible : 


Streptococcus mutans is the main cause of dental decay. Various lactobacilli are associated with progression of the lesion.

Even after brushing there is a constant increase in the number of bacteria in the oral cavity . Have a look at this video that shows the increase in the bacteria in the oral cavity after brushing . So now you know that you need to take care of oral hygiene, so that  the harmful caries causing microbes don’t increase in number.



Action of Acid on Tooth 

The tooth surface normally loses some tooth mineral from the action of the acid formed by plaque bacteria after ingestion of foods containing ferment-able carbohydrates. This mineral is normally replenished by the saliva between meals. However, when ferment-able foods are eaten frequently, the low pH in the plaque is sustained and a net loss of mineral from the tooth occurs. This low pH selects for aciduric organisms, such as S mutans and lactobacilli, which (especially S mutans) store polysaccharide and continue to secrete acid long after the food has been swallowed.
This Pic Shows areas in a tooth prone for Plaque Retention & Caries formation 
This pic shows how the bacteria produce acid on the tooth surface when in contact with food 


The biggest cause of tooth decay is the combined effect of bacteria + food + plaque + acid as stated in the picture above .

The bacteria feeds off sugars we eat, turning the sugar into acid and eroding our teeth. Over time, the plaque eats away at the enamel on our teeth, making them weak and susceptible to breakage, chipping, cracking, and other dental conditions. One enamel is eroded the sensitive parts of the tooth like dentin & pulp gets exposed to the caries . Other activities/risk factors  that cause tooth decay are:
  • Poor brushing
  • Not flossing
  • Waiting more than 20 minutes to brush after eating
  • Drinking less sugary beverages over a longer period of time
  • Not using MouthwashesRegularly
  • Not brushing the teeth before sleeping in night
  • DRY MOUTH ( decreased production of saliva )
Dry Mouth ( Also called as Xerostomia ) is also one of the main causes of dental caries . Saliva has many lytic enzymes that have the capacity to kill many pathogenic bacteria . When saliva production is less than the normal level , the natural cleansing activity is reduced .This give chance to the pathogenic bacteria to increase in number and produce more amount of acid that ultimately causes dental caries.

Food Habits that  bring higher risks of causing tooth decay:


Obvious/well known tooth decay causes:

  • Candy/sweets. Candy is a key offender!
  • Chocolate
  • Fizzy drinks and fruit juices
  • Biscuits/cookies
  • Ice cream
  • Jam/jelly

Less well-known causes of cavities (the sneaks):

  • Fruits
  • Potato chips/crisps
  • Breakfast cereals
  • Pretzels
  • Yogurts
So , Its all up to you , the consumer , to control and have a balanced diet that promotes dental health . Good habits like brushing before sleeping , avoiding sticky sugary foods , proper brushing – goes a long way in eradicating the causes of Dental Caries .


Read the next part of the article on Dental Caries here :