Dental curing light systems and methods

A dental curing light comprising:

• a curing light source configured to emit curing light at one or more wavelengths in a range from 400 nm to 800 nm, the curing light having a curing wavelength of maximum emission (λmax-cure), wherein curing of polymerizable dental material is induced by the curing light at the curing wavelength of maximum emission (λmax-cure);
• a monitoring light source that emits visible monitoring light at the polymerizable dental material at one or more wavelengths in a range from 400 nm to 800 nm, the monitoring light having a monitoring wavelength of maximum emission (λmax-mon), wherein the monitoring wavelength of maximum emission (λmax-mon) does not effectively induce polymerization of the polymerizable dental material;
• a visible light detector configured to detect the monitoring light after the monitoring light is diffusely reflected by the polymerizable dental material;
• and
• a controller operably coupled to the visible light detector, wherein the controller is configured to determine when the polymerizable dental material reaches a selected degree of curing based at least in part on a selected rate of change in intensity of the diffusely reflected monitoring light detected by the visible light detector.