Law & Order: Criminal Intent (2001)

S07E03 Smile

After a dentist is found dead at the hands of a patient's mother, Goren and Eames delve into the investigation, uncovering a web of deceit linked to a business that seems to have fallen prey to a plot involving tainted mouthwash. As they sift through the clues, they uncover a deeper conspiracy that puts the dental industry in jeopardy.