A study of the comparative efficiency of bactericidal and bacteriostatic agents in the mouth

Abstract

T HE mouth at all times is abundantly supplied with numerous species of bacteria, and practically every known form may be found there (rods, cocci, spiralas, etc.). The oral cavity represents one of the principal ports of entry for infectious diseases, and the flora does not always remain uniform from hour to hour or day to day. However, less than 1 per cent of the organisms are capable of causing disease. Also many of the organisms found in the mouth may become pathogenic under certain favorable environments and conditions. There is a constant variation of the type and number, and the fluctuation in the potential degree of pathogenicity of the organisms which compose them. The number of organisms is at the maximum at the time of arising in the morning, decreasing after meals, and gradually increasing during the intervals between meals. There is much evidence to dispute the efficiency of bactericidal agents in the mouth. Studies on the effects of various dentifrices and methods of mouth prophylaxis on the microbial flora of the mouth have shown that sterilization of the oral cavity is practically impossible. In any plan of mouth prophylaxis, clinical experience teaches that the best results are obtained with those agents that,are nonirritating in character. It is also generally known that all of the so-called bactericidal types of agents are irritating to a more or less extent. It is therefore necessary in the treatment of infection in the mouth to depend on a principle other than the mere killing of organisms. It would seem that the environment is of far more importance than the organisms themselves. Many types of organisms are present because of the environment in a particular lesion of the mouth. For instance, in the treating of a pericoronal area of acute infection about a mandibular third molar, our clinical experience shows that the most efficacious type of treatment is to irrigate the wound with a normal saline solution or other similar nonirritating solution and place a wick of cotton or gauze saturated with 5 per cent aqueous solution of mercurochrome in the pocket between the crown of the tooth and the overlying gum tissue. Rodriquez,*l Simmons,** and others have shown that germs grow in some of these mercurochrome solutions and that the mercurochrome is not bactericidal in effect. We do know, however, that it is bacteriostatic, and there is some possibility that its efficiency depends on its nonirritating properties and its ability to cleanse the area of infection mechanically and chemically. On the other hand, in these cases. when even a diluted form of iodine is used (a solution known to have a more