Some patients with oral lichen planus (OLP) experience recurrent oral candidiasis(OC). Probiotic bacteria have shown to reduce the oral Candida count in vivo.

OBJECTIVE: To study whether probiotic intervention reduces recurrent OC in patients with OLP.

MATERIAL AND METHODS: Twenty-two patients with symptomatic OLP were enrolled in the double-blinded, randomized, placebo-controlled intervention study. Lozenges containing Lactobacilli reuteri (DSM 17938 and ATCC PTA 5289) or placebo were dissolved intra-orally three times daily for 16 weeks, after which patients were followed up for 36 weeks. Mucosal symptoms, VAS pain, OLP severity score, plaque index (PI) and gingival index (GI), Candida count/carriage, and OC and/or need for symptomatic treatment were registered. Statistical significance was set at p < .05.

RESULTS: No difference was observed between the groups during the intervention or follow-up in terms of recurrent OC (p = .966) or need for symptomatic treatment (p = 1.000). There was no difference in terms of Candida count (p = .96) or carriage over time (p = .511). GI decreased in the probiotic group and increased in the placebo group (p = .046). OLP severity score decreased in both groups during the study period (p = .039). Across the entire study period, the placebo group had higher VAS pain score (p = .037).

CONCLUSIONS: Probiotic intervention did not reduce recurrent OC or Candida count/carriage, but the study experienced recruitment problems, which may have influenced results.