Answer:
Smooth-surface decay.
Step-by-step explanation:
Dental caries is a multifactorial infectious disease of the hard tissues of the tooth (enamel and dentin) that arises on the surface of the tooth and can spread to the pulp. Smooth-surface decay are dental caries that originate on the smooth surfaces of the proximal general teeth, or in the gingival third of the facial and lingual surfaces. This cavity forms when plaque builds up and bacteria are not killed on the flat surface of the teeth.