Clinical and microbiological effects of subgingival application of a chlorhexidine gel in chronic periodontitis. A pilot study.

Clinical and microbiological effects of subgingival application of a 1% chlorhexidine gel were studied. Eleven patients with chronic periodontitis participated in the study. In each patient two pairs of single rooted teeth with at least 20% attachment loss and probing depth > 4 mm were selected. Contralateral sites were randomly allocated to test and control groups receiving chlorhexidine or placebo gel respectively. The gels were applied once daily for two consecutive days. The clinical parameters comprised plaque index, gingival index, probing pocket depth and bleeding on probing. The composition of the subgingival microbiota was estimated with use of dark field microscopy. Baseline measurements were taken two weeks prior to chlorhexidine application. Microbiological and clinical parameters were further monitored 2, 7, 14 and 28 days after the last gel application. Chlorhexidine gel application did not significantly change the composition of the microflora compared to placebo application. There were no major differences in plaque and gingival indices. Effects on probing pocket depth of the chlorhexidine gel application may have been disguised by an influence from the diameter of the needle with which the application was performed. Needles with a diameter of 25G resulted in increases in probing pocket depth which indicates a possible mechanical trauma. This effect was not observed when needles with a diameter of 23G were used.