Laser-induced changes in tooth mineral content can increase resistance to acid dissolution. This is best described as:

• A. Decrease resistance
• B. No effect
• C. Increase resistance
• D. Increase caries rate

Answer: (C)

Changes in mineral content and how the enamel crystals are organized can alter how susceptible enamel is to acid attack. When laser treatment causes dehydration and reorganization of the mineral phase, the enamel becomes more crystalline and denser with fewer and smaller pores. This makes the hydroxyapatite less soluble in acid, so its resistance to acid dissolution increases. In other words, the surface becomes harder to dissolve under acidic conditions, which is the protective effect described. The other descriptions would imply the opposite effect, no change, or a higher risk of decay, which doesn’t fit the observed outcome of laser-induced mineral changes.