RESUMEN
To assess the effect of xylitol on salivary mutans streptococcus [MS], plaque level, and caries activity in a group of Saudi mother-child pairs. A clinical trial of 60 mother-child pairs with high MS levels attending at King Abdulaziz University clinics were randomly grouped into experimental [received xylitol] and control [received fluoride varnish] groups [30 pairs each]. The study was conducted from February 2009 to July 2010 for 18 months period. At 18 months, the sample dropped to 21 [experimental] and 13 pairs [control]. Xylitol gum were given to mother and chewable tablets were given to children 3 times a day for a period of 3 months. Both groups received oral hygiene instructions, dietary counseling, and restorative treatment and examined to assess caries, plaque and MS levels at 6, 12, and 18 months. The number of mother-child pairs with high MS level in the experimental group decreased significantly at 18 months compared to baseline [p=0.001, p=0.000]. A statistically significant difference in plaque level was found between the experimental and control groups at 6 and 12 month in children [p=0.000,p=0.006], while in mother, a significant decrease was recorded in the experimental group only at 18 month compared to baseline. Control group showed statistical significant increase in caries throughout the study period [p=0.040, p=0.040]. The use of xylitol chewing gum by mother and chewable tablets by children, showed significant reduction of MS count, plaque score as well as caries experience