Comparison of antibacterial effect of probiotic yogurt against xylitol-containing chewing gum on salivary streptococcus mutans count, bacterial adherence and salivary ph in geriatric patients : A randomized controlled trial / Hadier Mahmoud Ahmed Gad ; Supervised Mona Ismail Riad , Omar Osama Shalaan

Thesis (Ph.D.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Operative Dentistry

Aim: This study was conducted to evaluate the effect of probiotic bacteria in yogurt on streptococcus mutans count, plaque adherence and salivary pH compared to xylitol-containing chewing gum.Methodology: 96 patients were randomized into two equal groups (n=48). Group 1 (intervention group) received probiotic yogurt (Activia, Danone) once per day and group 2 (control group) received xylitol chewing gum (Trident original) three times per day. The primary outcome was salivary streptococcus mutans count and secondary outcomes were interdental plaque streptococcus mutans count (by culturing on mitis salivarius bactiricin bacitracin agar), salivary pH (using digital pH meter) and bacterial adherence (using visuplac disclosing agent and Cool PHP software for image analysis).Results: For streptococcus mutans count in saliva, the results showed statistically significant reduction in the level of s. mutans over all the examined follow up periods of the study in probiotic yogurt group as well as xylitol gum group. Results of intergroup comparison showed statistically significant difference between the two materials in two weeks{u2019} timeline where probiotics showed higher level of reduction in MS count.This was followed by statistically non-significant difference between both materials after one month timeframe.Then statistically significant difference between both groups was found where xylitol showed higher level of reduction in MS count than probiotics after three months. Regarding results of interdental plaque s. mutans count, statistically significant reduction in the level of plaque bacterial count between follow up periods was found in both probiotic yogurt and xylitol gum groups. Results of intergroup comparison showed statistically significant difference between the two materials in two weeks{u2019} timeline where probiotics showed greater reduction in plaque bacterial count. Results showed statistically significant difference between the two materials in four weeks{u2019} timeline and three months{u2019} timeline where xylitol showed greater reduction in plaque bacterial count. Salivary pH results showed statistically significant increase in pH in probiotic yogurt group and xylitol gum group along the follow-up periods. Intergroup comparison showed non-significant difference in pH between both groups over all the study period. Bacterial adherence results showed statistically significant reduction in both xylitol and probiotic groups. Intergroup comparison results showed statistically significant difference between both groups where probiotics showed higher level of reduction of bacterial adherence compared to xylitol

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