C — Calculus - Hardened or calcified plaque that sticks to the teeth and causes decay and gum disease. It requires scaling by a dentist or dental hygienist to remove.
C — Cavity - Hole or weak area in a tooth, caused by tooth decay (caries).
C — Composites - Tooth-colored materials used as fillings or bonding to restore teeth. Most are made of resin, a plastic mixture filled with ground-up "glass" particles (silicon dioxide).
C — Crown ("cap") - Part of the tooth that's visible above the gum, or the artificial substitute for it. A restorative crown covers the top part of a tooth that is severely damaged or weakened by decay. A crown is made of metal, resin, porcelain, or porcelain-covered metal, and cemented onto the tooth.
C — Cuspid - Pointy tooth, also called a canine (for their resemblance to dogs' fangs), located on either side of the incisors, the four teeth in the very front of the mouth. Adults have four cuspids that are used to tear food, two on the top and two on the bottom.