Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 18 0 2021 09 29 3755 3755 Vajihe Barati Department of Pediatric Dentistry, Faculty of Dentistry Mashhad University of Medical Sciences, Mashhad, Iran Maryam Mehrabkhani Department of Pediatric Dentistry, Faculty of Dentistry Mashhad University of Medical Sciences, Mashhad, Iran Iman Parisay Department of Pediatric Dentistry, Faculty of Dentistry Mashhad University of Medical Sciences, Mashhad, Iran Niayesh Mastoori Private Practice, Mashhad, Iran 2020 09 01 2021 06 08 Objectives: This study aimed to assess the effect of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) and xylitol chewing gums, and probiotic yogurt, as chemical plaque control strategies, on periodontal parameters. Materials and Methods: This randomized clinical trial evaluated 120 eligible dental students that were randomly divided into four groups (n=30) for use of (I) CPP-ACP chewing gum, (II) xylitol chewing gum, (III) probiotic yogurt, and (IV) chlorhexidine (CHX) mouthwash. The oral hygiene index-simplified (OHI-S), Silness and Loe gingival index (GI), and Silness and Loe modified plaque index (PI) were measured before and on days 15 and 30 after using the products. Paired t-test or its non-parametric equivalent was used to analyze the parameters after the intervention compared with baseline. The study groups were compared using one-way ANOVA or its non-parametric equivalent. Results: The OHI-S did not change over time, and most participants had a good OHI-S. The CHX group had the most favorable, and the probiotic yogurt group had the least favorable GI. Pairwise comparisons of the groups did not reveal a significant difference in GI between the CPP-ACP gum and CHX groups (P>0.05). CHX caused the greatest improvement in PI, with significant differences with other groups. Conclusion: CHX was the most effective for improvement of periodontal parameters followed by CPP-ACP, which showed better results compared with other groups.   https://fid.tums.ac.ir/index.php/fid/article/view/3755