## **Core Concept**
The question pertains to dental calculus detection and measurement, specifically focusing on the index that utilizes a calibrated probe. Dental calculus, or tartar, is a hardened deposit that forms on teeth and can lead to periodontal disease if not managed properly. Various indices are used in dentistry to assess and record the presence and severity of dental calculus.

## **Why the Correct Answer is Right**
The correct answer, **.**, refers to the Silness-Tarnow Index. This index is indeed used for assessing and measuring dental calculus. It involves the use of a calibrated periodontal probe to detect and score the presence of calculus on dental surfaces. The Silness-Tarnow Index provides a detailed assessment, helping in the diagnosis and monitoring of periodontal disease progression.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not correspond with the Silness-Tarnow Index or any widely recognized index that uses a calibrated probe specifically for calculus measurement.
- **Option B:** Similarly, this option does not align with the correct index. Other indices might assess different aspects of oral health or use different methods for evaluation.
- **Option C:** This option is incorrect as it does not represent the Silness-Tarnow Index or any relevant index that uses a calibrated probe for calculus.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the Silness-Tarnow Index is particularly useful in clinical settings for its detailed assessment of dental calculus. It aids in the early detection of periodontal disease and in monitoring the effectiveness of treatment over time. Dental professionals should be familiar with various indices to choose the most appropriate one for their specific clinical needs.

## **Correct Answer:** . Silness-Tarnow Index