This review was first published in 2009 . The American Dental Association Centre for Evidence-based Dentistry has now published a critical summary of this review.
The original review included 12 clinical trials involving 1818 patients and concluded that a twice-daily regimen of Chlorhexidine gel (0.2 percent) applied every 12 hours for seven consecutive days can help reduce incidence of dry socket (DS).
The appraisers found that while there was a good search of three databases and a clear question was being addressed there were a number of limitations in the methodology. There was also heterogeneity in the frequency and duration of use of Chlorhexidine (CHX).
The appraisers concluded:-
This review shows use of CHX following extractions may reduce the incidence of DS. The magnitude of its effect and best regimen for use remains unclear. A gel at 0.2 percent CHX applied every 12 hours for seven days postextraction shows promising results. In the United States there are less products containing chlorhexidine . Chlorhexidine rinse at 0.12% is available and more studies on effect of rinse in reducing incidence of dry socket would have clinical relevance.
Other relevant reviews
A earlier review of this area was conducted in 2005:-
Caso A, Hung LK, Beirne OR. Prevention of alveolar osteitis with chlorhexidine: a meta-analytic review. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005 Feb;99(2):155-9. PubMed PMID: 15660084.