## **Core Concept**
Cervical restorations are dental restorations placed in the cervical region of teeth, often due to non-carious cervical lesions (NCCL) or cervical caries. The success of these restorations depends on various factors including the material used, tooth preparation, and the environment in which they are placed. A key challenge in the cervical region is the presence of a unique set of conditions that can affect restoration longevity.

## **Why the Correct Answer is Right**
The correct answer, **D. Gingival recession**, highlights a primary reason for the failure of cervical restorations. Gingival recession exposes the dentin in the cervical area, making it more susceptible to sensitivity, caries, and difficulties in achieving a durable bond for restorations. This condition can lead to marginal leakage, secondary caries, and restoration dislodgement. The gingival recession compromises the integrity of the tooth structure and the surrounding environment, making it challenging to maintain a long-lasting restoration.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While inadequate occlusion can affect restorations in general, cervical restorations are less likely to fail primarily due to occlusal forces compared to other factors specific to the cervical region.
- **Option B:** Caries can indeed affect restorations, but in the context of cervical restorations, caries is often a reason for the restoration rather than the failure of the restoration itself.
- **Option C:** Poor oral hygiene can contribute to the failure of dental restorations indirectly by promoting caries or gingival recession. However, it is not as direct a cause of cervical restoration failure as gingival recession.

## **Clinical Pearl / High-Yield Fact**
A memorable point for exams is that cervical restorations often fail due to difficulties in bonding to the dentin in the cervical area, which can be exacerbated by gingival recession. Clinicians should consider the use of materials and techniques that optimize bonding to dentin, especially in areas with gingival recession.

## **Correct Answer: D. Gingival recession**