Oral-Spray Bacillus Spore Probiotic in Preventing and Supporting Treatment of Dental Caries in Children

Despite advances in oral health care, cavities remain highly prevalent worldwide, especially among children. Conventional treatment methods focus on removing damaged tooth tissue but fail to completely eliminate or control pathogenic bacteria in the oral cavity, leading to a high risk of caries recurrence in the same or adjacent teeth. Probiotics are a promising biological therapy that can help restore balance in the oral microbiome. Among probiotics, Bacillus species are unique because they form spores that make them stable under harsh conditions, such as heat and storage. They can also produce enzymes and natural compounds with antibacterial, anti-inflammatory, and protective effects. These features make Bacillus probiotics strong candidates for oral health applications. This study is designed to evaluate the safety and efficacy of an oral-spray probiotic containing Bacillus subtilis ANA48 and Bacillus clausii ANA39 (LiveSpo® Smile CARE) in preventing and supporting the treatment of tooth decay in children. We hypothesize that this probiotic spray, when used regularly, will be safe and well-tolerated, while effectively reducing harmful bacteria in the mouth, preventing the progression of cavities, and improving overall oral health. Study Design: * Sample Size: 130 participants * Study Location: a primary school in Hanoi, Vietnam Intervention Description: A total of 130 eligible participants will be randomly assigned to two groups (n = 65 per group). Placebo Group will receive a 0.9% NaCl physiological saline, spray twice daily (morning and afternoon). Each application consists of two sprays at three sites (both dental arches and the front teeth), for a total of six sprays per use, continued for three consecutive months. Smile Care Group will receive an oral-spray probiotics containing ≥ 1 billion CFU/mL × 20 mL of Bacillus subtilis and Bacillus clausii (LiveSpo Smile CARE). The dosage, frequency, and duration of use will be the same as in the placebo group. All participants will receive the same standard dental care throughout the study, including the use of identical toothpaste, supervised weekly fluoride rinsing with 0.2% sodium fluoride (NaF), and scheduled follow-up visits. The probiotic and placebo sprays will be packaged in blinded bottles and administered according to the study protocol to maintain objectivity. Study Duration: 12-18 months