Causes of caries
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Caries is a bacterial-chemical process, which initially causes the tooth to lose mineral substances. The bacteria in the plaque form acid as a metabolic end product, which causes calcium phosphate to be released from the tooth's enamel. The weakened enamel further begins to crumble, causing the first small defect. The bacteria, which cause caries and form acid, can now demineralise the lower layers of hard dental substances. In this way, caries now moves further from the enamel to the dentin. Then, in the case of deep dentin caries, the acid and toxins of the bacteria can lead to an inflammation of the pulpa (pulpitis).
Caries can be subdivided according to the extent of the damage it has already caused. Caries initialis or caries superficialis occurs if the caries is located within the enamel. A caries affliction of the dentin is caries media or caries profunda, depending on the depth of the dentin caries.
Caries initialis
Initial caries is still reversible. The loss of minerals in the enamel is displayed as a whitish spot. It can be repaired through the redeposition of mineral substances. The affected areas are treated with a fluoride gel or a fluoride solution. This serves to promote the redeposition of mineral substances (remineralisation).
Caries superficialis
Superficial (surface) caries is irreversible. A first cavity is created by the mineral loss occurring under an intact tooth surface. Defects such as these represent ideal hiding places for bacteria. Plaque is permanently present in these defects. The acid formed by the bacteria cannot be neutralised by saliva and leads to a further loss in minerals. The expansion of caries superficialis is as yet still limited to the enamel and does not cause pain.
Caries media
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If the carious process reaches the dentin, we speak of caries media. The bacteria can now advance more rapidly through the little dentin canals within the dentin. Caries can thus also advance more rapidly. Dentin caries can expand considerably, even under an almost intact dental enamel surface.
In the case of extensive caries media, the probe remains stuck in the softened dentin. The larger the defect, the more frequently decay processes (bacterial decay of food residues) take place.
Caries profunda
If the dentin caries reaches the proximity of the pulpa, we speak of caries profunda. The carious defect with softened dentin has encompassed large areas of the tooth. Without therapy, the tooth will be destroyed by the caries and as a consequence of bacterial damage caused to the pulpa a pulpitis (inflammation of the dental pulp) would develop.