Which caries type is defined as lesions occurring in relation to an existing restoration?

• A. Occlusal caries
• B. Beginning occlusal caries
• C. Recurrent caries
• D. Proximal caries

Answer: (C)

Recurrent caries are lesions that occur at the margins or around an existing restoration. They form when the seal at the tooth–restoration interface fails, allowing bacteria to invade and start decay adjacent to or beneath the restoration. This specific location—in relation to a previous restoration—sets it apart from other types: occlusal caries develop on the chewing surfaces, proximal caries appear on the interproximal surfaces between teeth, and a beginning occlusal caries is simply an early stage on the occlusal surface. So when a lesion is defined as occurring in relation to an existing restoration, recurrent caries is the best fit.