The effect of chlorhexidine mouthrinses on early bacterial colonization of guided tissue regeneration membranes. An in vivo study.

Abstract

Different membrane materials accumulate varying amounts of bacteria when exposed in the oral cavity, due to their textural and structural surface characteristics. The aim of the study was to evaluate the effect of chlorhexidine mouthrinses on the in vivo early bacterial colonization of 3 different guided tissue regeneration membrane materials. Rectangular-shaped strips cut from 3 periodontal membranes (expanded polytetrafluoroethylene, polyglactin 910, and polylactic acid) were glued to removable devices adapted to the 2 upper quadrants in 8 dental students. In each student 1 quadrant was randomly selected as test side while the other served as control side. The experiment was divided in 2 phases: in the first phase plaque accumulation was followed for 4 hours while the second accumulation was followed for 24 hours. During the 4-hour experiment, students rinsed the test device twice (immediately following device application and after 2 hours) with 0. 12% chlorhexidine solution. The control device was rinsed with saline. In the second phase, students rinsed the test device with chlorhexidine and the control devices with saline 3 times (after device application and at 8 and 16 hours). Both the 4-hour and the 24-hour specimens were processed for scanning electron microscopy analysis. Fifty-four fields (at 200x magnification) were randomly selected and analyzed on each strip. Magnification was increased to determine the presence and morphotype of bacteria. The presence or absence of bacteria was assessed in a binomial fashion: the field was bacteria-positive when bacteria constituted the deposits covering the membrane surface. The microscopic field was negative (bacteria-negative) when no bacteria were observed. Bacteria-positive fields showing rods and filaments as prevalent morphotypes were recorded as rod-positive fields. The results of data analysis suggest that bacterial contamination of membrane materials is significantly reduced by treatment with chlorhexidine. They also suggest that other variables affect plaque accumulation as well; i.e., the time allowed (4 versus 24 hours) and the different membrane materials. The interaction between these 2 variables is also highly significant, thereby indicating a different rate of plaque accumulation on different materials, irrespective of the treatment with chlorhexidine. It was concluded that chlorhexidine mouthrinses may be effective in reducing and delaying the early bacterial accumulation on membrane materials although they are not able to fully prevent it. Membrane surface characteristics seem to be a more critical factor than the use of chlorhexidine, in influencing bacterial adhesion and colonization of barrier materials.