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A tooth may be sensitive to cold, hot or sweet things when the inner dentine layer of the tooth is exposed.  Unlike the harder outer enamel layer of the tooth, the dentine layer is quite porous.  When this layer is exposed to cold, hot or sweet things, the nerve of the tooth is irritated and you get that sensitive feeling.

Let’s look at 4 common reasons for this exposed dentine and the resultant sensitivity:

1. Tooth Decay

When bacteria use the sugar left on your teeth after eating and ineffective cleaning, they produce acid.  This acid eats into your tooth and damages the enamel layer, exposing the dentine layer.  Cold, hot and sweet things on the damaged tooth may then cause sensitivity.

2. Cracked Tooth

A tooth that takes a lot of force, be it biting very hard things, clenching and grinding or a physical knock to the jaw, can become cracked.  A crackline through the enamel to the dentine is a direct pathway for cold, hot and sweet things to irritate the nerve of the tooth.

3. Gum Recession

The gums normally cover the dentine around the necks of the teeth.  If the gums recede due to gum disease or physical trauma such as hard toothbrushing, the dentine usually covered by the gum is exposed.  Exposed tooth structure where the gums have receded is now sensitive to cold, hot and sweet things.

4. Tooth Wear

Like with all parts of the body, wear and tear catches up with our teeth.  The enamel layer becomes more worn down over time and the underlying dentine is exposed.  The teeth can become increasingly sensitive to cold, hot and sweet things.

Sensitive Toothpastes?

Sensitive toothpastes may help sensitive teeth by blocking the porosities in the exposed dentine.  The problem is that the blocking ingredients leech back out over time so you have to continually use the sensitive toothpaste to have that anti-sensitivity effect.  It’s best to see the dentist to diagnose and treat the cause.