Chlorohexidine has an immediate bacteriocidal effect but inhibits the formation of plaque by which mechanism?

Chlorhexidine is a broad-spectrum antimicrobial agent commonly used in dentistry for its dual action of killing bacteria and inhibiting plaque formation. Its ability to inhibit plaque development is primarily attributed to its adsorption to the pellicle, which is a thin film that forms on the teeth shortly after cleaning.

When chlorhexidine is applied to the oral cavity, it binds effectively to the salivary pellicle due to its cationic nature (it carries a positive charge). This binding prevents bacteria from adhering to the tooth surface. The pellicle serves as a substrate for bacterial colonization, and by binding to this substrate, chlorhexidine disrupts the initial stages of plaque formation.

The positive charge of chlorhexidine also plays a role in its bactericidal action by allowing it to interact with the negatively charged bacterial cell membranes, leading to cell lysis. However, the primary mechanism cited for its ability to inhibit plaque formation is its ability to absorb to the pellicle and create a barrier that minimizes bacterial attachment.

This concept is essential in understanding how chlorhexidine functions within oral hygiene regimens, particularly in preventing dental plaque accumulation and managing periodontal diseases.