Effect of MI Paste Plus™ on Streptococcus Mutans and White Spot Lesions in Fixed Orthodontics

Background This study is part of a doctoral research project at Universidad Cardenal Herrera CEU (Spain), directed by Prof. Santiago Arias de Luxán and conducted by doctoral candidate Shirli Kelmendi within the PhD program in Translational Medicine. Fixed orthodontic appliances complicate oral hygiene by creating retention areas that favor bacterial colonization and alter microbial balance. These conditions increase plaque accumulation and Streptococcus mutans (S. mutans) proliferation in saliva and plaque. The frequent low-pH environment favors aciduric bacteria such as S. mutans and lactobacilli, promoting enamel demineralization and formation of white spot lesions (WSLs) or cavitations. WSLs appear as opaque white areas due to subsurface mineral loss, mainly in the gingival third of the crown. They may develop as early as one month after bracket placement, while in patients without appliances, progression occurs after at least six months. Increased S. mutans levels have been reported as early as six weeks after treatment start. Risk factors include poor brushing, lack of floss or rinse use, time since last cleaning, and presence of caries or lesions. Intervention MI Paste Plus (GC, Japan) is a remineralizing cream with 0.20% sodium fluoride (900 ppm) and 10% CPP-ACP (RECALDENT™), providing calcium and phosphate stabilized by casein phosphopeptides. It has antibacterial and remineralizing effects, suitable during or after orthodontic treatment to prevent or reduce WSLs. Objective To evaluate whether MI Paste Plus during fixed orthodontic treatment reduces S. mutans counts in saliva and/or WSL incidence. Study Design A prospective, triple-blind, randomized clinical trial, approved by the Ethics Committee of the Ministry of Health of Albania and the Ethics Committee for Human Research of Universidad Cardenal Herrera CEU, Spain. The study will include 200 patients (100 per group) from two orthodontic clinics in Tirana, Albania. Participants will be stratified by age, risk level, and appliance type, then randomized by third parties. Outcome Measures Primary variables: S. mutans counts in saliva and number of WSLs after 3 months. Standardized saliva collection, culturing, and bacterial quantification ensure consistency. Clinical assessments will be performed at 1 and 3 months using QRay Cam Pro (Inspektor Systems, Netherlands) for quantitative fluorescence and ICDAS for visual inspection. Data will be analyzed using SPSS/R Commander software.