The purpose of this research study is to compare responses in children during dental
injections of local anesthetic (used for numbing), while children are under deep sedation
(breathing on their own, often with a loss of consciousness). Two types of local anesthetic
will be used--one will be buffered (by adding a salt solution to make it less acidic), while
the other will be plain, without anything added. Previous studies have shown that the
addition of the buffer solution can improve comfort during a dental injection.