2.下列專有名詞的解釋,何者正確?
A.attrition: pathological wearing away of tooth structure secondary to a chemical agent.
B.abrasion: loss of tooth structure caused by a non-bacterial chemical process.
C.demastication: tooth wear accelerated by chewing an abrasive substance between opposing teeth.
D.perimolysis: loss of tooth structure caused by a mechanical process.