Which of the following conditions does NOT indicate the need for restorative dentistry?

The condition that indicates the absence of cavity or structural damage is the one that does not require restorative dentistry. When the dental anatomy is healthy and shows no signs of decay, there is no need for restorative procedures since restorative dentistry aims primarily to repair or replace damaged or decayed teeth.

In contrast, initial decay necessitates intervention to prevent the progression of caries. Failed restorations indicate that previous attempts to repair a tooth have not been successful, thus requiring further restorative action. Abrasion of tooth structure points to wear that could affect dental health and may also require restorative measures to protect and restore functionality.

Given these points, a healthy condition without decay means there is no indication for restorative treatments, making it the only option that does not warrant such actions.