CRD summary: This review concluded that stannous fluoride dentifrices reduce gingivitis and plaque formation in comparison with conventional dentifrices, but that differences in outcome measures make it difficult to assess the magnitude of the effect. However, given the variability of the studies and limitations in the review methods, the reviewers' conclusions may not be reliable.

CRD commentary: The review stated a clear question and inclusion criteria. The search was limited so it is possible that relevant studies were missed. The reviewers made little apparent effort to search specifically for unpublished studies and, as only English language studies were eligible, it is possible that language and publication bias may have been introduced into the review, as the authors acknowledged. The authors reported methods to reduce errors and bias when selecting the studies, but it is unclear whether similar approaches were used for the data extraction and quality assessment processes.

The results of the individual studies appeared diverse overall and only a few studies indicated a statistically significant benefit of SnF2. Only a small selection of the identified studies was included in the pooled analysis; the pooled selection may not be a good representation of the existing evidence base. In view of these limitations, and as the authors themselves advised, the conclusions should be interpreted with caution.