In dentistry, calculus or tartar is a form of hardened dental plaque. It is caused by precipitation of minerals from saliva and gingival crevicular fluid (GCF) in plaque on the teeth. This process of precipitation kills the bacterial cells within dental plaque, but the rough and hardened surface that is formed provides an ideal surface for further plaque formation. This leads to calculus buildup, which compromises the health of the gingiva (gums). Calculus can form both along the gumline, where it is referred to as supragingival, and within the narrow sulcus that exists between the teeth and the gingiva, where it is referred to as subgingival.
YEREVAN, Armenia (AP) — Heavy fighting between Armenian and Azerbaijani forces over the separatist region of Nagorno-Karabakh continued for a fourth straight day on Wednesday, in the biggest.. WorldNews - Published
Armenia and Azerbaijani forces kept fighting Monday over the disputed separatist region of Nagorno-Karabakh after hostilities broke out the day before, with both sides blaming each other for resuming.. WorldNews - Published