**Question:** Burtonian lines on gums is seen in poisoning with

A. Lead
B. Mercury
C. Zinc
D. Arsenic

**Core Concept:** Burtonian lines on gums are characteristic appearance of herpetic gingivostomatitis (herpes simplex virus infection) on the gums. The lines represent the fusion of the epithelial cells due to viral infection.

**Why the Correct Answer is Right:** Burtonian lines are a clinical manifestation seen in cases of herpes simplex virus (HSV) infection, specifically herpes gingivostomatitis. HSV is a common cause of oral herpes, which results in the fusion of epithelial cells in the gums, leading to the formation of Burtonian lines. This viral infection can be caused by either HSV type 1 or HSV type 2, although HSV type 1 is more common in causing oral lesions.

**Why Each Wrong Option is Incorrect:**

A. Lead poisoning: Lead poisoning presents with stomatitis, which is inflammation of the gums without specific linear changes.
B. Mercury poisoning: Mercury poisoning typically results in gingivitis (inflammation of the gums) rather than Burtonian lines on the gums.
C. Zinc poisoning: Zinc poisoning can cause stomatitis, but it does not result in the characteristic Burtonian lines seen in herpes infection.
D. Arsenic poisoning: Arsenic poisoning may cause gingivitis or stomatitis, but it does not result in Burtonian lines on the gums.

**Clinical Pearl:** Burtonian lines are a key clinical feature in the diagnosis of herpes gingivostomatitis. In cases with suspected viral infection, it is essential to investigate the presence of Burtonian lines to confirm the diagnosis.

**Correct Answer:** D. Arsenic

Arsenic poisoning can cause stomatitis, but it does not result in the characteristic Burtonian lines seen in herpes infection. Arsenic poisoning typically presents with oral lesions such as ulcers, vesicles, and erosions, which may also involve the gums, but the linear pattern is not observed. Therefore, Arsenic is the correct answer among the given options.