Probiotic fermented sheep’s milk containing Lactobacillus casei 01: Effects on enamel mineral loss and Streptococcus counts in a dental biofilm model

The effects of probiotic fermented sheep’s milk containing Lactobacillus casei 01 on enamel demineralization and microorganism counts in a mixed biofilm model were investigated. Enamel blocks (N = 50) were fixed in polystyrene plates in which a mixed biofilm (Streptococcus mutans 25175, Streptococcus parasanguinis 903, and Streptococcus salivarius 8618) was formed. The mature biofilm was treated for five days with the following: (1) sheep’s milk (SM); (2) fermented sheep’s milk with starter culture (FSMS); (3) fermented sheep’s milk with probiotic culture (FSMP); and (4) fermented sheep’s milk with starter and probiotic cultures (FSMSP). A growth control group was also included (brain–heart–infusion medium with inoculum). The percentage of surface hardness loss (%SHL) and total microorganism and Streptococcus counts (log10 colony-forming units/mL) were calculated. In addition, mean internal mineral density loss determination (ΔZ) by micro–computed tomography and descriptive topographic analysis via scanning electronic microscopy (SEM) were performed. No group prevented %SHL (p = 0.168), with a similarity in values (p > 0.05) confirmed in SEM images. No differences were found between the tested groups and growth control group in terms of total microorganism or Streptococcus counts (p > 0.05). In relation to total microorganism reduction, FSMS and FSMP were similar (p = 0.153), presenting a reduced number of microorganisms. Both were different from FSMSP (p