Usually, they only trigger pain when the tooth's inner pulp and its nerves are already inflamed.
通常情况下,它们只在牙齿的内部牙髓及其神经已经发炎的情况下才引发疼痛。
英语百科
Pulp (tooth)
The dental pulp is the part in the center of a tooth made up of living connective tissue and cells called odontoblasts. The dental pulp is a part of the dentin–pulp complex (endodontium). The vitality of the dentin-pulp complex, both during health and after injury, depends on pulp cell activity and the signaling processes that regulate the cell’s behavior.