Dental cleanings (Oral Prophylaxis) are recommended twice a year for most patients with good periodontal status (periodontium = supporting structures of the teeth. i.e. – the bone, gingiva (gums) and periodontal ligament (the ligament that holds each tooth to the bone in the socket). During oral prophylaxis, calculus (tartar), the hard build-up of bacteria in a matrix of material released by the bacteria and the precipitation of minerals from saliva, is removed with dental instruments in a process called scaling (or debridement) to prevent gingivitis and ultimately periodontitis. Plaque is also removed in the process and during the polishing procedure accomplished with a prophy cup and polishing paste. This also helps to remove stains from the teeth caused by the normal process of eating and drinking and from vices like smoking. Fluoride varnish (brushed on the teeth) is available to patients who want it, and helps to prevent tooth sensitivity and repair enamel.