Western Society of Periodontics

Clinical Studies

Volume Number 3, 1995

Bacterial penetration in vitro through GTAM membrane with and without topical chlorhexidine application. A light scanning electron microscopic study

The purpose of this study was to evaluate the capacity, under controlled conditions, of topical chlorhexidine application to exposed membranes to limit bacterial colonization and invasion through the membrane. Three healthy individuals were selected on the basis of excellent periodontal health. A special device was made from a removable acrylic denture base to which five gold cusps were attached. The cusps consisted of an internal compartment, isolated from oral cavity by a GTAM membrane, and an external compartment exposed to the oral cavity. This device was inserted into the molar-premolar region of the upper jaw. The cusps of one side of each subject received a 0.2% chlorhexide gluconate gel twice a day for one minute, whereas the cusps of the other side were maintained moist as control. Twelve cusps were removed after two weeks and the rest removed after one month. The results showed that the control specimens had greater amounts of plaque accumulation. Plaque deposits increased in thickness and quantity in all the cusps during the weeks. Complete invasion of the membrane and initial colonization of the internal surface of the membrane were observed in four-week specimens. Histologic observation showed a reduced thickness of bacterial deposits on the external surface of the chlorhexidine-treated membranes after two and four weeks of exposure to the oral cavity. A relatively simple flora, consisting mainly of cocci and short rods, was found in bacterial deposits forming under the influence of chlorhexidine, whereas a more mature and complex plaque, made up of filamentous-shaped bacteria, appeared in nontreated samples. The inhibition of calculus formation was visible in the histologic sections of the two- and four-week specimens from the treated side. In conclusion, this study has shown that 0.2% chlorhexidine topical gel application for one minute twice a day is an effective method of reducing plaque and calculus formation on the surface of e-PTFE membranes exposed to the oral cavity for a period of up to four weeks. However, this study failed to demonstrate the capacity of chlorhexidine to prevent bacterial penetration through the thickness of inner portions of GTAM membranes. [S.L.]