Teeth are important players in the digestive process.
As teeth grind up food, debris accumulates on the tooth surface and attracts bacteria. This accumulation of debris and bacteria is called plaque. Plaque is easily removed from teeth by brushing—that is, when teeth are brushed frequently.
If the plaque isn't brushed away, mineral deposits cause it to harden on the teeth. This is called tartar. Dark yellow or brown accumulations on the teeth are indicators of tartar, which is difficult to remove.
If left untreated, plaque can lead to damage of the gums (gingivitis) or the jawbones and teeth (periodontitis).