<prompt> Many dentists criticized the poor quality of the early amalgam restorations and this controversy led to the amalgam war from1820 to 18301840 to 18501870 to 18801880 to 1890  <response>: Many dentists criticized the poor quality of the early amalgam restorations.This controversy led to the amalgam war from 1840 to 1850.Reference: Phillips Science of Dental Materials, Pg-8 