**Question:** Dental Plaque adheres to tooth surface by

A. Surface tension
B. Electrostatic forces
C. Lipid bilayers
D. Adhesion molecules

**Correct Answer:** D. Adhesion molecules

**Core Concept:**
Dental plaque is a complex microbial biofilm that forms on the tooth surfaces, primarily composed of Gram-positive bacteria. The adhesion of dental plaque to the tooth surface is a crucial step in the initiation and progression of dental caries and periodontal diseases. This process involves various types of adhesion molecules that facilitate bacterial attachment and colonization.

**Why the Correct Answer is Right:**
Dental plaque adhesion is primarily due to the interaction between bacterial adhesion molecules and host cell receptors on the tooth surface. This adhesion is mediated by various bacterial adhesins (adhesion molecules) that interact with host cell receptors, such as gingival collagen, fibronectin, and laminin. These adhesion molecules facilitate the attachment of bacteria to the tooth surface, allowing the biofilm to develop into a mature plaque.

**Why Each Wrong Option is Incorrect:**
A. Surface tension does not directly contribute to bacterial adhesion to tooth surfaces. Instead, it plays a role in the cohesion and organization of the dental plaque biofilm.
B. Electrostatic forces are not the primary mechanism of dental plaque adhesion. Adhesion molecules and host cell receptors play a more significant role in this process.
C. Lipid bilayers are a structural feature of cell membranes in living organisms, not involved in bacterial adhesion to tooth surfaces.

**Clinical Pearl:**
Understanding the mechanisms of dental plaque adhesion is essential for preventive and therapeutic strategies to control dental plaque-related diseases. Proper oral hygiene practices, such as regular brushing and flossing, aim to disrupt bacterial adhesion and biofilm formation to prevent dental caries and periodontal diseases. Additionally, some antimicrobial agents and dental materials, like fluoride and photo-polymerizable composites, target adhesion molecules to reduce bacterial colonization and biofilm development.