Meth mouth is a clinical manifestation of methamphetamine abuse in the oral cavity. It is characterized by severe acidic tooth decay, gum disease, and crumbling and rotting of teeth. The teeth may eventually fall out. Common determinants of meth mouth are xerostomia secondary to methamphetamine abuse, lockjaw, and bruxism. Reference: https://www.addictioncenter.com/drugs/meth/meth-mouth/ Image via: https://www.juliegillisdds.com/blog/meth-mouth/
Similar issues with pain medications as Methadone at high doses and or long term use where healthy teeth will normally crack simultaneously causing the teeth to deteriorate and turn black. Infections can and will cause heart problems.