Preventive Effect of a Probiotic Tablet on Oral Health in Preschool Children

Background In spite of the general decline in dental caries, early childhood caries (ECC) is still a severe global problem with social and behavioural gradients [1, 2]. The disease is multi-factorial but the key event is a pH-induced stress in the oral environment that results in reduced diversity of the oral biofilm [3]. The biofilm simply adapt to this situation with an overgrowth of caries-associated aciduric strains on behalf of beneficial and health promoting bacteria. Therefore, the addition of probiotic bacteria has been suggested as a novel approach to maintain oral health as an adjunct to the existing evidence-based methods [4, 5]. Previous clinical trials have indicated that a daily intake of lactobacilli-derived dairy products can reduce caries incidence, improve general health and diminish the use of antibiotics in preschool children [6, 7, 8]. However, further studies on the probiotic concept are needed; all children do not drink milk and no studies on childhood caries have hitherto been conducted with non-dairy products and streptococci strains.

Objectives The aim of the present project is to evaluate the effect of daily administration of chewing tablets containing probiotic bacteria (Probiora3) on plaque amount, gingival health and caries incidence in preschool children. In addition, information on general health will be collected. The null hypothesis is that the oral health will not differ from preschool children with a similar intake of placebo tablets. An additional aim is to monitor the microbial composition in saliva samples at baseline and during the course of intervention.

Study design The study design is a prospective randomised, double-blind, placebo-controlled trial with two parallel arms. The duration is 12 months. Assignment to intervention and control group will be made by a computer-based randomization in groups A or B.

Material The study group will be recruited among the 2-year-old children that are regular patients attending the Public Dental Clinic in Rosengård, Malmö, Sweden. The clinic is situated in a multicultural suburban area with a low socio-economy. The proportion of immigrants is high in the area, the majority Arabic speaking. The inclusion criteria are i) uncompromised general health, ii) no cavities or severe dental diseases, and iii) not mentally or physically disabled. Children that are uncooperative or totally reject dental examination are excluded. The children will be consecutively enrolled after signed informed consent (verbal and written) by their parents and assigned to either the test or the control group by pre-numbered envelopes generated by a computer program. As a new patient is entering the study, the clinician takes the next numbered envelope assigning the patient to either group A or B. The protocol has been subjected to the regional ethical committee and is approved.

Power calculation A power calculation of the clinical scores with alpha set at 0.05 and beta = 0.2 estimates that 85 subjects in each arm is needed to disclose a 30% difference between the treatment groups with respect to the clinical scores (Fleiss Statistical Methods for rates and Proportions, 2nd edition, John Wiley and Sons New York 1981). Due to expected relocations and failure to comply with the protocol, the goal will be to recruit a minimum of 220 and a maximum of 250 children.