Is the following a slander case?My daughter is in second grade. She has to use the bathroom alot during the day. She drinks a lot of water. ...

No, this is not a slander case.  I am assuming that the
meeting that you attended was specifically meant to address your daughter's issues (as
opposed to a public meeting on other issues).  In this context, the teacher's statements
are presumably not being made with malicious intent and are part of her duties as a
teacher.

When a parent asks to meet with teachers and
administration about a student's problems, the teacher has to give her professional
opinion about the student.  If a teacher knowingly says something false and malicious,
there could be grounds for a slander case.  However, the teacher presumably cannot
know that her statement about your daughter's intentions is
false.  Teachers do have to make professional judgements about what students are doing
all the time.

Unless the teacher knew that her statement
was false and unless she was making those statements for a malicious reason, she has not
slandered your daughter.

Of course, that does not mean that
she handled the meeting well.  She could have said things in a nicer way, perhaps.  But
being rude or thoughtless is not the same as slander.