Hi. There are multiple causes for such a problem. Heartburn or gastric reflux is a common cause of loss of taste. Stomach acid regurgitated into the mouth produces a loss of normal taste. poor dental hygiene causes bacterial growth in the mouth or ulcers can also cause loss of taste. Vitamin b12 and zinc deficiency also leads to impaired taste. I would advice take an opinion from a dentist. Get a scaling if needed. Switch back to your old tooth paste for some time and see if the problem resolved. Still if not resolved, contact a general physician for the same