Lower left toothache may be caused by dental disease or cardiovascular disease, the specific need to check the oral cavity and clinical symptoms to determine. 1. Dental diseases: the left lower toothache may have dental caries, pulpitis, apical periodontitis, deep caries will be into the cavity of the food produced by a transient pain, pulpitis will be outside hot and cold stimuli produce intense pain, pain continues to have spontaneous pain, apical periodontitis will be on the lower occlusal pain, pain, knocking. 2. cardiovascular disease: heart attack and other cardiovascular diseases caused by toothache often appear after strenuous exercise, radiating pain in the teeth, can be radiated to the head or back, clinical examination of the teeth usually no dental disease. The specific cause of lower left tooth pain needs to be determined in the hospital according to clinical manifestations and laboratory tests.