During a routine dental visit the dentist or hygienist: Check medical history to identify underlying conditions or risk factors (such as smoking) that may contribute to gum disease. Examine your gums and note any signs of inflammation. Use a tiny ruler called a ‘periodontal probe’ to check for and measure any pockets. In a healthy mouth, the depth of these pockets is usually between 1 and 3 millimeters. Take an x-ray to see whether there is any bone loss. Refer you to a periodontist if periodontal condition is moderate to severe and if the periodontal condition is not reacting well to treatment.