The Mixture of Topical Anesthetic and Chlorhexidine at the Delivery Site in Microbial Reduction Efficiency

Antimicrobial properties of some anesthetic agents have been reported which may be useful for infection control. Topical lidociane (10%) showed some extent of antimicrobial activity on oral microflora.

This study aimed to determine whether the antimicrobial efficiency of topical lidocaine can be enhanced by adding chlorhexidine.

The Lidocaine-Chlorhexidine (LD-CHX) preparation was prepared by mixing 2.0% CHX and 10% LD with various ratios. The anesthetic efficiency was tested on the oral mucosa of 26 volunteers by Pin Prick Test. Pain scores were recorded using the Numerical Rating Scale (NRS). Antimicrobial effects of 10% LD, 0.2% CHX, and LD-CHX preparations were evaluated. In vitro study was conducted against seven standard bacterial strains. For in vivo study, oral biofilms of 26 volunteers were collected by imprint technique using filter papers. Bacterial growth from the samples after applying the test solutions was compared to the control. Antimicrobial efficiency was expressed as microbial reduction scores from 4-0 (highest to lowest).

The LD-CHX preparations that had comparable anesthetic efficiency to 10% LD were those containing 9% and 8% LD. These LD-CHX preparations showed microbial reduction scores of 3 and 4 on seven bacterial strains and oral biofilms.

This study showed the antimicrobial and anesthetic effectiveness of new lidocaine-chlorhexidine preparations both in vitro and in vivo. We also confirmed the effectiveness of infection control protocol in oral surgery using CHX mouthwash prior to topical LD.