Background: Since scaling and root planing are not always successful, predominantly when access to periodontal defects is compromised, various antimicrobial agents as adjuncts have been suggested to enhance their efficacy. Gel vehicles delivering chlorhexidine (CHX) have become available and tested for these indications.

Methods: An electronic (MEDLINE and Cochrane Oral Health Group Specialized Trials Register) and manual search were made to detect studies concerning the use of chlorhexidine gels as a single measure of treatment and as an adjunct to scaling and root planing. Only full-text randomized controlled trials published in English up to January 2005 were included.

Results: Eight studies were finally selected. Due to considerable heterogeneity in study design and outcome variables measured a qualitative data analysis was performed. There is evidence that subgingival chlorhexidine gel administration as a monotherapy temporarily reduces bleeding tendency on probing; a clinical effect coinciding with relevant microbiological changes described in all but one study. To what extent chemical effects contribute to these changes appears to be related to the frequency of gel administration. There seem to be little to no data indicating that the treatment outcome of scaling and root planing will benefit from the adjunctive subgingival administration of a CHX gel.

Conclusion: The limited data currently available on the effects of subgingival chlorhexidine gel application do not justify its use in the treatment of chronic periodontitis.