How Tooth Decay Develops
The most common cause of tooth decay is dental plaque — a buildup on the teeth that contains bacteria and food particles, especially carbohydrates. If the teeth are not brushed properly and regularly, plaque accumulates. In the presence of bacteria (most commonly Streptococcus mutans), acids are produced that gradually damage the tooth enamel, marking the beginning of the caries process.

Progression of Tooth Decay
Tooth decay progresses from the enamel layer into the dentin (the layer beneath the enamel). In dentin, caries spreads much faster, both in depth and width. At this stage, patients usually feel pain when consuming something cold or sweet, which indicates that the decay is approaching the pulp (“tooth nerve”).

If left untreated, the infection reaches the pulp, causing spontaneous, intense pain that can last from a few minutes to half an hour. As the condition worsens, pain-free periods become shorter, while episodes of pain become more frequent and more severe — this stage is known as pulpitis.

When the Infection Advances
If treatment is still not provided, the “nerve” dies, and the infection spreads into the tooth root and surrounding bone. The tooth becomes sensitive to touch, tapping, or biting. The inflammation progresses, potentially leading to swelling, severe pain, and the formation of a fistula (a small channel through which pus drains to the surface of the oral mucosa). At this stage, endodontic treatment (root canal cleaning) is necessary.

Why Prevention Matters
For all the reasons mentioned above, prevention and regular dental check-ups are essential. It is recommended to have your teeth professionally examined at least twice a year to detect caries in its early stage and prevent complications.

With modern materials (metal-free composites), it is possible to restore lost tooth structure both aesthetically and functionally, without the need for the metal fillings that were commonly used in the past.