Aim: The effect of magnolia bark extract (MBE) on the development of caries lesions administered daily through sugar-free chewing gum was evaluated. A randomized double-blind intervention trial was performed. <br>Methods: 480 subjects (mean age±40.72) were examined using ICDAS index. A self-compiled questionnaire was submitted. A caries risk profile was generated for each subject using Cariogram software. 271 subjects, presenting inclusion criteria, were enrolled and divided into three groups (blue, yellow and green): one using chewing gum containing MBE and xylitol, another group using chewing gum with xylitol but free of MBE and finally, a control group using a sugar-free chewing gum. Each subject was instructed to chew one pellet for 5 min 3 times a day for 12 months. Plaque-pH using the strip method, a clinical examination using ICDAS scores and a microbiological evaluation (CRT Bacteria) were assessed at baseline(t₀), after 6 months(t₁) and 12 months(t₂) of chewing gum use. Data were analysed for statistically significant differences using repeated measures of ANOVA.</br> Results: Data on 193 subjects were calculated and the total sample showed a plaque acidogenicity and salivary concentration of bacteria at t2 significantly lower compared to baseline. <br>Conclusion: The Cariogram model was able to identify the caries-related factors in adults. Twelve-month use of sugar-free chewing gum showed beneficial effects on oral health, controlling plaque acidogenicity to reduce caries risk.</br>