In dentistry, calculus or tartar refers to hardened plaque on the teeth, formed by aging in the presence of saliva, debris[?], and minerals. Its rough surface provides an ideal medium for bacterial growth, threatening the health of the gums[?] and absorbing unaesthetic stains far more easily than natural teeth.
All Wikipedia text
is available under the
terms of the GNU Free Documentation License
Search Encyclopedia
Search over one million articles, find something about almost anything!
... were brought for compulsory service during World War II, to work in the coal mines. Other than native aboriginal tribes the majority of the residents of the island ar ...