You will be provided with the titles and abstracts of a collection of medical RCT reports studying a clinical question -- for instance, the efficacy of an intervention on some medical outcome. Please write a few sentences synthesizing the findings of these reports, which could serve as a conclusion section for a systematic review article. Your response should not include any other text. The RCT reports are below.



Title 1:
Tongue-cleaning methods: a comparative clinical trial employing a toothbrush and a tongue scraper.
Abstract 1:
It is estimated that approximately 85% of all halitosis cases have their origin within the mouth; of these, 50% are caused by tongue residues. Previous studies have established that hydrogen sulfide and mercaptans are the primary components of halitosis. Thus, tongue cleaning gains importance as a means of halitosis management.
                This investigation compared the efficacy of two mechanical methods for tongue cleaning through a handheld sulfide monitor. This crossover trial was carried out with 10 healthy subjects, 20 to 50 years old. Before the baseline measurement of the volatile sulfur compounds (VSCs), the subjects were instructed to refrain from any tongue cleaning method for 48 hours. The 10 participants were then placed in one of two groups (five each): 1) first week: tongue scraper, second week: soft-bristle toothbrush; 2) first week: toothbrush, second week: tongue scraper, with a 48-hour wash-out period between each week.
                The baseline measurements were compared with those of the end of each week using the Dunn method (alpha = 0.01). The tongue scraper showed a 75% reduction in VSCs, while the toothbrush only achieved a 45% reduction in VSCs.
                Although the tongue coating was removed by both methods, the tongue scraper performed better in reducing the production of volatile sulfur compounds.


Title 2:
Effectiveness of mechanical tongue cleaning on oral levels of volatile sulfur compounds.
Abstract 2:
Mechanical tongue cleaning may be an effective method for decreasing oral levels of volatile sulfur compounds, or VSC, and oral malodor. The authors conducted a study to compare the effectiveness of a specially designed tongue cleaner (One Drop Only Tongue Cleaner, One Drop Only, Berlin), a tongue scraper and a toothbrush in reducing oral VSC levels.
                In this balanced, crossover study, 30 subjects had four morning appointments each with a waiting period of one week between appointments. At each appointment, a dental professional performed a single standardized tongue cleaning procedure using one of the cleaning tools. The authors monitored the subjects' oral VSC values using a portable sulfide monitor until their baseline VSC values were reached.
                The baseline values showed no significant difference between the three groups. The tongue cleaner and the tongue scraper (42 percent and 40 percent, respectively) reduced oral VSC levels more than the toothbrush (33 percent) did. Reduced VSC values could be detected significantly longer after using the tongue cleaner than after using the tongue scraper or the toothbrush. The authors, however, could not detect a significant VSC reduction for more than 30 minutes in any of the subjects.
                The tongue cleaner, a combination brush and scraper, was slightly more effective in reducing oral VSC levels than were the tongue scraper and a regular toothbrush. Because of the limited duration of the effect, however, the clinical efficacy on the reduction of oral malodor remains questionable.
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.