**Question:** Mobility of teeth in carcinoma of Maxillary sinus is due to involvement by tumor of

A. Palatine bone
B. Nasal bones
C. Maxillary sinus mucosa
D. Lymph nodes

**Core Concept:**
In cases of maxillary sinus carcinoma, the tumor may invade surrounding structures, leading to symptoms such as tooth mobility. In this scenario, the tumor's impact on the teeth is primarily due to involvement of specific anatomic structures.

**Why the Correct Answer is Right:**
The correct answer, **C. Maxillary sinus mucosa**, is chosen because the maxillary sinus mucosa is directly involved in cases of maxillary sinus carcinoma. As the tumor grows, it can erode and infiltrate the mucosal lining of the maxillary sinus, leading to pressure and spread to adjacent structures. This process, known as tumor infiltration, results in tooth mobility.

**Why Each Wrong Option is Incorrect:**

A. **Palatine bone (A. Palatine bone)**: Maxillary sinus carcinoma typically involves the mucosa first, not the bony structures like the palatine bone. While bony invasion may occur later, the initial cause of tooth mobility would be mucosal involvement.

B. **Nasal bones (B. Nasal bones)**: Similar to the palatine bone, the nasal bones are not primarily affected in early maxillary sinus carcinoma. Mucosal invasion is the initial mechanism leading to tooth mobility.

D. **Lymph nodes (D. Lymph nodes)**: While lymph node involvement is a later event in the progression of maxillary sinus carcinoma, it is not directly responsible for tooth mobility due to the tumor's primary effect on the mucosa.

**Clinical Pearl:**
In cases of maxillary sinus carcinoma, closely monitor patients for tooth mobility as it may signify early mucosal involvement and subsequent spread to adjacent structures. Early detection and intervention are crucial for better prognosis and patient management.

**Correct Answer:** C. Maxillary sinus mucosa