Reversal of primary root caries lesions after daily intake of milk supplemented with fluoride and probiotic lactobacilli in older adults

Abstract

Objective. To evaluate the effect of milk supplemented with fluoride and/or probiotic bacteria on primary root caries lesions (PRCL) in older adults. Materials and methods. After informed consent, 160 healthy subjects, 58–84 years of age, with at least two PRCL were recruited and randomly assigned to one of four parallel study groups drinking 200 ml milk once daily for 15 months. Group A consumed standard milk (placebo); Group B ingested milk supplemented with 5 ppm F and probiotic bacteria (Lactobacillus rhamnosus LB21, 10⁷ CFU/mL); Group C drank milk with only probiotic bacteria and group D milk contained only fluoride. Primary endpoints were Root Caries Index (RCI) and electric resistance measurements (ECM) carried out by one blinded single examiner. Secondary endpoints were mutans streptococci and lactobacilli counts in saliva and plaque estimated with chair-side tests. Data were compared within and between groups with non-parametric tests. Results. The drop out rate was 38%. At baseline there were no statistical differences between the groups. Significantly higher numbers of RCI reversals were found in groups B, C and D compared with group A (p < 0.05). The mean ECM values increased significantly (p < 0.05) in all groups except for the placebo group A, indicating that remineralization occurred. The effect was most beneficial in the two groups that contained fluoride. No significant alterations were displayed regarding the microbial counts. No severe adverse effects were reported during intervention. Conclusion. Daily intake of milk supplemented with fluoride and/or probiotic bacteria may reverse soft and leathery PRCL in older adults.

Key Words::

• ECM
• fluoride
• milk
• remineralization
• root caries

Acknowledgements

The authors would like to thank Mrs Inger Sjöström, Department of Odontology, Faculty of Medicine, Umeå University, and Mrs Ann-Charlotte Gustafsson, Specialist Dental Clinic, Ljungby for their skillful technical and clinical support. The test products were produced by Probac AB and Norrmejerier Ekonomisk Förening, Umeå, Sweden and the smooth cooperation is thankfully acknowledged. The study was supported financially by grants from The Borrow Foundation, UK and the County Councils of Västerbotten (TUA) and Halland, Sweden.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the performance and evaluation of the study protocol as well as for the content and writing of the paper.