Can tooth decay cause a toothache?

Tooth decay is one of the most common causes of a toothache. As decay progresses, it can penetrate the outer enamel layer and reach the softer dentin underneath, which contains tiny nerve endings. This can cause sensitivity and pain, especially when eating or drinking hot, cold, or sweet substances. If the decay is not treated, it can continue to progress deeper into the tooth, eventually reaching the pulp, where the tooth’s nerves and blood vessels are located. At this stage, the pain can become more severe and constant, often requiring more extensive treatment such as a root canal to resolve.