Long-term antiplaque, anticalculus, and antigingivitis effects of benzethonium/polymer complex in beagle dogs

An electrostatic complex of 0.1% benzethonium chloride (BTC) plus 0.05% copolymer of methoxyethylene and maleic acid was evaluated in vitro for antibacterial effect. The complex by itself showed as much antibacterial activity as 0.1% BTC. The adsorption of 14C-BTC on saliva-coated hydroxyapatite disks and teeth in vitro was lower from the complex than the BTC solution, although in vivo activity was the same. The complex, BTC, and polymer solutions were evaluated in a 28-week study in 16 beagle dogs against plaque, gingivitis, and calculus formation. BTC and the complex significantly (alpha = 0.05) reduce plaque and gingivitis. There was no significant difference between the two active groups. BTC (0.1%) significantly increased calcified deposits at 22-28 wk compared to the water control group, while the complex and the polymer groups showed significantly (alpha = 0.05) less calculus. Thus, the complex was not only effective in vivo, but also significantly (alpha = 0.05) reduced tendencies of cationic antibacterials to induce calcified deposits on teeth.