Why can tooth decay not cause pain?

The explanation lies in the structure of the tooth. In the early stage, the caries lesion affects only the tooth enamel, the outermost and most resistant layer of the tooth. As enamel has no nerve endings, its degradation does not cause pain.

At this stage, tooth decay develops silently, and may only show itself through subtle signs, such as:

• White or opaque spots;

• Small changes in the texture of the tooth;

• Loss of lustre of the enamel.

Without the clinical monitoring provided by regular maintenance appointments, these signs can easily go unnoticed.

How tooth decay progresses over time

The progression of decay occurs in different stages:

1. Demineralisation of the enamel

It is the initial and reversible stage. It results from the action of acids produced by the bacteria present in dental plaque and in tartar.

2. Progression to the dentine

When decay passes through the enamel, it reaches the dentine - a more sensitive structure. Here, the first symptoms associated with caries lesions may appear, such as sensitivity to cold, heat or sweet foods.

3. Involvement of the dental pulp

In an advanced stage, the infection reaches the pulp (where the nerves are), causing intense pain and inflammation.

It is at this stage that many patients seek help - when the situation already requires more invasive treatments and, in extreme cases, can even lead to the premature loss of the tooth. 

Main causes of tooth decay

Decay does not arise by chance. It is associated with several factors:

• Accumulation of bacterial plaque; 

• Frequent consumption of sugars; 

• Insufficient oral hygiene; 

• Reduced saliva flow; 

• Difficulty cleaning certain areas, such as the interdental spaces. 

Misaligned or crowded teeth can worsen this risk, as they make effective brushing more difficult and favour plaque retention.

How to know if you have decay (even without pain)

Even without pain, there are signs that may indicate the presence of decay:

• Tooth sensitivity that is mild and occasional; 

• Persistent bad breath; 

• Localised darkening on the tooth; 

• Frequent trapping of food in a specific area; 

• Small visible cavities. 

Still, the safest and most effective way to diagnose it is through a clinical assessment and complementary examinations, such as X-rays.

Why tooth decay is often diagnosed late

There are two main reasons:

1- Lack of early symptoms

        As there is no pain, the problem is ignored.

2- Lack of regular appointments

        Without check-ups, early lesions are not identified in time.

Result: when the diagnosis is made, the decay is already at a more advanced stage.