Stages of Caries: From Initial to Deep

Caries is one of the most common human diseases: more than 93% of people are affected by it. Destruction proceeds slowly and does not cause pain at first, so the stage is often determined by the dentist during an examination rather than by the patient themselves. Below is what the process looks like from a spot to a cavity, and why the absence of symptoms guarantees nothing.

What caries is and how it develops

Caries is a chronic disease of the teeth in which hard tissues are destroyed by acids produced by bacteria. First, focal demineralization of the inorganic part of the enamel occurs and its organic matrix is destroyed, then a cavity forms in the dentin, and without treatment inflammatory complications arise from the pulp and periodontium.

Oral bacteria convert sugar and starch into acids, which together with food debris and saliva form a sticky plaque. Plaque accumulates within 20 minutes after eating, and if it is not removed, it hardens and turns into tartar. Acids damage the enamel, which is 96% minerals and begins to break down at a pH of 4.5. Plaque most often accumulates on the posterior molars, near the gumline, and along the edges of fillings.

Carious cavities come in different colors — from yellow to black — and the disease itself is more common in children and young adults: in children it ranks first among chronic diseases and occurs 5–8 times more often than bronchial asthma.

Initial caries: a spot without a cavity

The initial stage looks like a spot — white, brown, or black, without a hole. The enamel in that area has lost some of its minerals, but there is no cavity yet, and there are usually no sensations either. This stage is called initial, and it is reversible: an early lesion can be stopped with fluoride agents — varnish or mouthwash — selected by the dentist.

Caries with a cavity in the dentin

The boundary between the superficial and moderate stages, that is, how deeply the process has advanced into the dentin, is determined by the dentist during an examination. When the process passes through the enamel, a cavity forms in the dentin — the very hole in the tooth. On examination, the tooth surface may feel soft, and an X-ray shows some cavities earlier than they are visible to the eye.

Symptoms at these stages: pain or an aching sensation, sharp pain when eating and drinking — especially hot, cold, or sweet. Sometimes nothing hurts at all. A cavity usually requires a filling; with extensive destruction and a small volume of remaining tissue, a crown.

Deep and advanced caries

Deep caries is when the destruction has reached the soft tissue in the center of the tooth (the pulp) or has affected it. Then root canal treatment may be needed, and sometimes the tooth has to be removed. An untreated lesion destroys the inner part of the tooth and leads to inflammation of the pulp and periodontium.

The advanced variant is a story of complications: infection with a painful accumulation of pus (abscess), tooth fracture, inability to chew on that side, bone infection, bone loss, and tooth loss. The rate of destruction is individual: it is influenced by carbohydrates in the diet, frequency of snacking, fluoride in the enamel, saliva, and hygiene.

Why caries can be painless

Cavities usually do not hurt until they become very large, affect the nerves, or cause a tooth fracture. Therefore, "nothing hurts" does not equal "everything is fine": a spot or a hole can remain unnoticed for years.

How the dentist determines the stage and when not to postpone a visit

Diagnosis begins with an examination: the doctor assesses the color and density of the tissues, looks for cavities, and checks whether the tooth surface is soft. X-rays and tests for caries susceptibility help — enamel staining, assessment of plaque, bacterial traces, and tissue resistance to acids; the result is described as high, moderate, or low resistance.

• pain or sharp pain when eating and drinking;
• visible pits, holes, or dark spots on the tooth;
• painful, swollen, or bleeding gums;
• tooth sensitivity to sweet, hot, and cold.

Caries by itself is not a reason to call an ambulance. 103/112 — if the condition is life-threatening and rapidly worsening.

A routine check-up is appropriate even when nothing is bothering you: examination and professional cleaning are usually done once every 6 months, and X-rays for high-risk areas are done once a year. Treatment at an early stage is less painful and costs less.

This material is for reference and does not replace a doctor's consultation: the stage and management in each case are determined by the dentist together with the patient.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer