Call it dental caries or tooth decay or simply, a cavity. Yes. These are the few names for that hole in your tooth. Tooth decay is a very common oral health problem affecting the young and old alike. But have you wondered how a tooth decay, which starts as a tiny hole, can destroy the whole tooth?
Plaque formation is the precursor
Pellicle – a very thin layer made up of saliva, proteins, and bacteria – is formed on the tooth surface a few minutes after brushing. It acts as a protective barrier on the teeth. Within a few hours a pale yellow or white sticky substance known as dental plaque is formed by the accumulation of various species of bacteria along with sugar from the food we eat. Plaque develops on the tooth surfaces throughout the day.
It’s a tug of war
The bacteria in the plaque ferment the food particles present on the surface of the tooth to produce acid. The acid causes demineralization of the tooth enamel. If there is gum recession, the acid can attack the cementum of the tooth root too. The demineralisation process takes place as long as the tooth is exposed to plaque. A white chalky spot, one of the first signs of decay, may appear where minerals have been lost. When the plaque is removed through brushing and flossing, the tooth can counteract the damage by replacing lost minerals through minerals obtained from saliva, fluoridated toothpastes, etc.
When outdone, your tooth gives in
Your tooth does not develop cavities just overnight. It can take months, or even years, for the decay process to form cavities. The tooth goes through demineralization and remineralisation cycle all day long. Situations like heavy dental plaque, intake of sugary or sticky food, frequent snacking, etc. can cause the demineralisation process to exceed remineralisation. When demineralisation gets the upper hand, the enamel or cementum progressively breaks down producing cavities or holes in the tooth.
If untreated, decay can spread further inside
If left untreated, it can get larger and affect the inner layers – dentin and pulp- of the tooth. Once the decay reaches the second layer, i.e. the dentin, it progresses faster and you may experience sensitivity in the tooth. But dentin, unlike enamel, reacts to the advancement of decay to form sclerotic and tertiary dentin. Dentin is made up of many tiny channels called dentinal tubules which help transmit sensation of pain and touch to the pulp. As tooth decay progresses through the dentinal tubules the calcium and phosphorus released by demineralisation of enamel are precipitated deeper into the dentinal tubule. Mineralization of the surrounding tubules increases resulting in a constriction of the tubules and formation of sclerotic dentin. This helps slow the progression of bacteria. The dentin may also respond to the dental caries by producing more dentin, called tertiary dentin, towards the pulp. This helps protect the pulp from bacteria for as long as possible. From a tiny problem to a more serious one
Failure to get the tooth filled will cause more damage to the tooth and the decay spreads to pulp, the innermost layer of the tooth with nerves and blood vessels. When bacteria enter the pulp it causes inflammation of the pulp. The infection from the pulp may also spread to the fibres that attach tooth to the bone (periodontal ligament). Infected pulp will eventually die and can lead to an abscess. The bacterial infection from the abscess can spread and cause complications like a dental cyst (fluid-filled cavity),sinusitis, osteomyelitis (infection of the bone) or sepsis (infection throughout the body) and rarely potentially fatal conditions like Ludwig’s angina (swelling and intense pain under the tongue and in the neck) and cavernous sinus thrombosis (blood clot in a large vein at the base of the brain).