What describes the first stage in the formation of a carious lesion in a previously sound tooth?

The first stage in the formation of a carious lesion is characterized by the demineralization of the enamel. This process begins when acids produced by bacteria in the dental plaque start to dissolve the minerals in the enamel, particularly hydroxyapatite. This initial phase is often subtle and may not present any visible signs on the surface of the tooth.

During this stage, the enamel loses calcium and phosphate ions, leading to changes in its structure. If demineralization continues without intervention, it can progress into a carious lesion, potentially leading to further deterioration and entering deeper layers of the tooth, such as the dentine. This makes the understanding of demineralization critical in the prevention and management of dental caries, emphasizing the importance of good oral hygiene and regular dental check-ups.

The other options involve stages that either come after demineralization or describe processes that occur at deeper levels of tooth structure, not the initial phase of carious lesion development.