A Cochrane systematic review finds tongue scrapers have short-term efficacy in controlling halitosis

the tongue cleaner or the tongue scraper demonstrated a statistically significant difference in reducing levels of volatile sulfur compounds (VSCs) when compared with the toothbrush. The findings indicate 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.