Background: Halitosis is used to describe any disagreeable odour of expired air regardless of its origin. Mouthwashes which disguise oral malodor are more socially acceptable and generally more popular than tongue scrapers.
Objectives: To provide reliable evidence regarding the effectiveness of tongue scraping versus other interventions (including mouthwashes) to control halitosis.
Search strategy: We searched the following databases: Cochrane Oral Health Group Trials Register (to 15th September 2005); the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3 2005); MEDLINE 1966 to September Week 1 2005; EMBASE 1974 to September 2005 (searched September 19th 2005).
Selection criteria: Randomized controlled trials comparing different methods of tongue cleaning to reduce mouth odour in adults with halitosis.
Data collection and analysis: Clinical heterogeneity between the two included trials precluded pooling of data, therefore a descriptive summary is presented.
Main results: This review included two trials involving 40 participants. Both trials were methodologically sound but included no data for the primary outcomes specified in this review. Secondary outcomes expressed as volatile sulfur compound (VSC) levels were assessed by a portable sulfide monitor in both trials. One trial showed reductions of VSC levels of 42% with the tongue cleaner, 40% with the tongue scraper and 33% with the toothbrush. Reduced VSC levels persisted longer with the tongue cleaner than the toothbrush and could not be detected for more than 30 minutes after the intervention in any of the groups. Differences were assessed by the Friedman and Wilcoxon signed rank tests with the level of significance set at P < 0.05. The second trial, in which differences in totaled rank values between groups were compared by the Dunn method alpha = 0.01, showed a reduction of VSC levels compared with baseline measurements of 75% with the tongue scraper and 45% with the toothbrush. Adverse effects in one trial were nausea (60%) and trauma (10%) with the toothbrush and all participants receptive to using the tongue scraper. Based on the independent data from these two trials there was a statistically significant difference between the effectiveness of either the tongue cleaner or the tongue scraper in reducing VSC levels when compared with the toothbrush.
Authors' conclusions: There is weak and unreliable evidence to show that there is a small but statistically significant difference in reduction of VSC levels when tongue scrapers or cleaners rather than toothbrushes are used to reduce halitosis in adults. We found no high level evidence comparing mechanical with other forms of tongue cleaning.