Dentin decay
Dentin decay is tooth decay that has passed through enamel into the softer layer beneath, where it can progress toward the pulp and cause sensitivity.
The short answer
Dentin decay is tooth decay that has passed through enamel into the softer layer beneath, where it can progress toward the pulp and cause sensitivity. Treatment depends on whether the tooth structure can be restored and whether the pulp is inflamed.

What is the direct answer?
What does this question mean?
Dentin is the mineralised tissue under enamel and cementum. Bacterial acids dissolve minerals after plaque bacteria use fermentable carbohydrates; once the lesion reaches dentin, its tubules can transmit temperature and touch toward the pulp.
What can you do next?
Brush twice daily with fluoride toothpaste, clean between teeth, and reduce frequent sugary drinks or snacks. A dentist may remove infected tooth structure and place a filling; a deeper lesion may require pulp treatment followed by a definitive restoration.
When should you seek dental care?
Arrange an examination for sensitivity, a food-catching hole, toothache, or a dark or fractured area. Urgent care is needed for spontaneous severe pain, facial swelling, fever, pus, or difficulty swallowing.
What should you ask the dentist?
Ask how deep the lesion is, whether the pulp is affected, and whether a radiograph is needed. Ask which restoration will replace the missing tooth structure and how to prevent decay on the other teeth.
Frequently asked questions
Does dentin decay always hurt?
No. Decay can be painless, particularly before it irritates the pulp or causes a structural defect.
Can fluoride rebuild a cavity in dentin?
Fluoride supports remineralisation of early mineral loss, but a cavitated dentin lesion generally needs a dentist’s assessment and restorative care.
