Mainly look at the cause of toothache, if it is "liquefactive necrosis's pulp", because the pressure in the pulp cavity is high, so hot substances will aggravate the pain, while cold substances can reduce the pressure, thus achieving the effect of relieving the pain.

For the pain relief of acute pulpitis, oc (clove oil) and some analgesic drugs, such as triamcinolone acetonide (acetaminophen) and fenbid (ibuprofen), are commonly used in clinic.

Finally, I suggest that if you have a serious toothache, you should see a doctor as soon as possible, because the above measures can only relieve the symptoms, but not cure the cause.