Singulair Cavities, Baby Teeth, Floss, Fortunately, Root Canal

I have a six year old son who has asthma. He has been taking singulair and Flovent every day for 4 years. He also has a lot of the side effects that I see listed on this site. I was wondering if anyone with children taking Singulair have more cavities than their other children. My son with astham is the youngest of four child and last week we found out he had four cavities. One was so bad he needed root canal. Fortunately, these were all baby teeth. My destist said it is because he does not floss since the cavities started between teeth. Most moms I spoke to said their kids do not floss and never had a cavity! I'm just wondering if there is a connection between cavities and Singulair
Joanne