Scripps News and USA TODAY spent more than a year examining the North American Dental Group. Reporters interviewed dozens of its former dentists, employees and patients and reviewed thousands of pages of documents from courts, dental boards, patient records, social media reviews and other sources. The investigation found that the intense pressure on North American Dental’s offices to meet daily revenue targets led to allegations of overtreatment. Patients complained they were diagnosed with a mouthful of cavities only to later discover nothing was wrong with their teeth. Former employees said they felt uncomfortable with what they witnessed.