In which of the following a nonfunctional cusp is present:
**Core Concept**
A nonfunctional cusp is a morphological feature of a tooth that does not contribute to the masticatory function. It is often seen in teeth that have undergone significant wear or trauma. The presence of a nonfunctional cusp can be an important diagnostic feature in dental and maxillofacial radiology.
**Why the Correct Answer is Right**
The correct answer involves identifying a tooth that typically exhibits a nonfunctional cusp. The cusp of Carabelli is a nonfunctional cusp that is often seen on the maxillary first molars. It is a small, rounded cusp that is located distally to the buccal groove of the tooth. The cusp of Carabelli is a result of the fusion of two separate teeth during embryonic development and is a common feature of the maxillary first molar in many populations.
**Why Each Wrong Option is Incorrect**
* **Option A:** This is not a known tooth with a nonfunctional cusp.
* **Option B:** This is not a known tooth with a nonfunctional cusp.
* **Option C:** This is not a known tooth with a nonfunctional cusp.
**Clinical Pearl / High-Yield Fact**
The cusp of Carabelli is a key diagnostic feature in the identification of maxillary first molars on radiographs. It is often used as a reference point for locating the buccal groove and other important anatomical features of the tooth.
**Correct Answer:** C. Cusp of Carabelli is typically seen on maxillary first molars.