At what pH level does enamel and dentine demineralisation begin?

Enamel and dentine demineralisation is a critical process in dental health, and it occurs at specific pH levels due to the influence of acids in the oral environment. The correct answer, a pH level of 5.5, is significant because it represents the threshold where the mineral content of enamel begins to dissolve in the presence of acid.

At this pH, the balance shifts towards demineralisation, which can be exacerbated by factors such as bacterial metabolism of sugars that produces organic acids. When the pH falls below 5.5, it becomes favorable for the dissolution of hydroxyapatite, the primary mineral in enamel, leading to potential caries development.

Maintaining a pH above this level is essential for oral health, as it allows for the remineralisation process to occur. The constant cycle of demineralisation and remineralisation highlights the importance of salivary buffering, dietary choices, and oral hygiene in preventing dental decay.