**Question:** A severe blow to a permanent anterior tooth not resulting in fracture, commonly leads to

A. root resorption
B. tooth discoloration
C. root caries
D. dental pulp necrosis

**Correct Answer:** A. root resorption

**Core Concept:** Root resorption is a process by which dental pulp cells, primarily odontoclasts, break down tooth structure (dentin and/or cementum) in response to various stimuli, such as trauma, tooth movement, or orthodontic forces. This process leads to tooth size reduction and may cause sensitivity, pain, or even tooth loss if not treated.

**Why the Correct Answer is Right:** In this scenario, a severe blow to a permanent anterior tooth does not result in fracture, which means the tooth's integrity is compromised but not fractured. Root resorption is a possible outcome in such cases, as the dental pulp is exposed to external stimuli and can initiate the resorption process.

**Why Each Wrong Option is Incorrect:**

B. Tooth discoloration (Option B) is not the common outcome of a severe blow. Although discoloration may occur, it is less likely compared to root resorption due to the trauma.

C. Root caries (Option C) is a dental condition characterized by demineralization of the tooth structure due to bacterial activity. In this case, root caries is incorrect because the tooth is not infected or demineralized but rather experiencing root resorption due to trauma.

D. Dental pulp necrosis (Option D) is a condition where the dental pulp dies due to infection, trauma, or other factors. In this scenario, the tooth is not infected but rather experiencing resorption, making dental pulp necrosis an incorrect answer.

**Clinical Pearl:** Root resorption is an essential concept to understand in dentistry, particularly in treating traumatized teeth. Early diagnosis and intervention are crucial to preserve the tooth and maintain its function and esthetics. In cases of traumatized teeth, referral to a specialist (endodontist) is often necessary for proper management and treatment options, such as root canal therapy or extraction, if required.