Background. Several multicenter random clinical trials have studied a second-generation easy-to-use chlorhexidine local delivery system to assess its effectiveness as an adjunct to scaling and root planing, or SRP.
Methods. The author reviews the pharmacokinetics of the local delivery system and two of the multicenter randomized clinical trials. One study evaluated 118 patients using split-arch design and the other study 447 patients using parallel design. All patients underwent SRP. Test sites, which had pocket depths of 5 millimeters or larger, received a chlorhexidine chip (in both studies) or a placebo chip (the parallel study only). Test sites that remained 5 mm or larger were re-treated with a chip at three months and at six months (parallel study only).
Results. Both studies found greater mean reductions in probing depth when the chlorhexidine chip was used in conjunction with SRP than when SRP was used alone (1.16 mm vs. 0.7 mm, P 
.0001, in the split-arch–design study and 0.95 mm vs. 0.65 mm, P = .00001, in the parallel-design study). The combined therapy resulted in significantly more sites with probing depth reductions of 2 mm or more compared with SRP alone (49.5 percent vs. 32.1 percent; P < .0001, in the split-arch–design study and 19.1 percent vs. 8 percent, P < .0001, in the parallel-design study).
Conclusions. Use of the chlorhexidine chip has significantly improved the clinical parameters of periodontitis when used as an adjunct to SRP.
Clinical Implications. When used with SRP, the chlorhexidine chip offers the clinician a new method of achieving and maintaining periodontal stability.
