Dental clinic Small Smiles criticized for performing poor, unnecessary procedures The national children's dental clinic Small Smiles is under fire after an investigative report revealed allegations that the chain's clinics have been performing substandard work and unnecessary dental procedures - responsible for increasing taxpayer cost. The accusations come from numerous parents, former employees of the company and government investigators, who are concerned about the exploitation of children's health. According to an NBC News investigation of 63 Small Smiles clinics over the past three years, the alleged practices are in direct violation of a settlement the chain made with the Department of Justice in early 2010. The settlement was in response to previous allegations accusing the company of performing unnecessary and substandard dental procedures on low-income children. After the 2010 incident, the company managing Small Smiles, Church Street Health Management, agreed to significantly alter the procedures within the clinics, as well as undergo independent monitoring, NBC said. The company also agreed to pay $24 million - without admission of guilt. However, the NBC investigative report, along with public health records, show that Small Smiles has not learned its lesson. While the clinics have improved somewhat since CSHM declared bankruptcy in June of 2012, replacing their CEO, letters from the Department of Health and Human Services Office of the Inspector General (HHS OIG) say that the company's compliance is inconsistent - and sometimes disturbing. RELATED: Phoenix family sues Reachout America for unnecessary dental work According to a 2011 audit of a Manassas, Va., clinic, only 104 of 244 root canals performed on babies were found to be medically unnecessary, and another audit of an Ohio clinic found multiple instances of medically unnecessary or poorly done root canals - leading to a $100,000 fine. One mother, Autum Archuleta, told NBC News about the time she took her almost 3-year-old son Nathan to a Small Smile clinic, where he underwent three crowns, two root canals and six silver fillings in just 25 minute. Archuleta said she ran into the treatment room when she heard her son screaming - only to find him being held down by three employees and wrapped in a stabilization device. Small Smiles clinics provide dental treatment for low-income children, receiving millions of dollars in income through Medicaid. Despite threats to the company that they may lose their ability to accept federal funds, CSHM received $150 million in revenue from Medicaid in 2011, NBC said. The HHS OIG has continually threatened CSHM to clean up their act, giving them numerous second chances. However, Senator Chuck Grassley (R-IA) told NBC News that it's time for the company to be shut down for good. Click for more from NBC News.