Testing the Impact of Dental Probiotics on Oral Malodor

Objectives: Sulfur producing bacteria on the tongue cause oral malodor (OM). Tongue scraping and dental probiotics are means of reducing the insult. However, there have been limited studies showing the relationship between probiotics and tongue scraping as it relates to OM. The objective is to determine if dental probiotics provide additional benefit to tongue scraping in reducing OM.
Methods: Twenty-one people were assigned to either a ‘no tongue hygiene’ control (group A, n=6), a ‘tongue scraping+placebo mint’ regimen (group B, n=8), or a ‘tongue scraping+probiotics’ regimen (group C, n=7) for 30 days. There was a run-in period of 7 days before the trial where all participants refrained from tongue hygiene. Pre-trial and post-trial measurements were made using a Halimeter to detect sulfur compounds in breath, and microbiological counts were obtained by plating a tongue swab on blood agar and on oral-hydrogen-sulfide-organism-carbohydrate (OHO-C) agar, which changes color to indicate sulfur producing colonies. The bacteria were cultured anaerobically for 48h at 37°C.
Results: There was a statistically significant reduction in breath sulfur only in group C (p=0.016).Total bacterial counts dropped in groups B and C but the differences did not reach statistical significance. There was a trend with 5/7 participants in group C showing a reduction in sulfur producing bacteria measured on OHO-C, whereas only 4/8 in group B and 2/6 in group A showed reductions.
Conclusions: Adding oral probiotics to an oral hygiene regimen of tongue scraping significantly reduced OM when measured with a Halimeter. The microbiological basis for this reduction remains uncertain, but may have been due to replacement of sulfur producing bacteria on the tongue by the probiotic strain.