Calculus is due to poor oral hygiene, no timely brushing, teeth will accumulate food debris, soft tartar, plaque, plaque will form a layer of biofilm on the surface of the teeth, this layer of biofilm, in the oral saliva under the action of calcium, phosphorus, will be gradually mineralized, mineralized layer by layer deposition to the surface of the teeth, and over time it will become a hard tartar. Tartar makes the surface of the teeth is not smooth, more conducive to the deposition of plaque, pigment, soft tartar, thus forming a vicious circle, tartar will become bigger and bigger, and become the causative factor of periodontitis and gingivitis. Tartar and the roots of the teeth are more closely combined, through daily brushing, rinsing, it is difficult to completely remove clean, so you need to go to the hospital on a regular basis, ultrasonic cleaning is also known as scaling, through the ultrasonic shock, the tartar will be broken down, so that it is detached from the surface of the teeth, in order to completely clean it off.