On a criminal record, is dismissal of a case the same as it being exspunged?

i had my misdemeanor dismiss last year, but i was told it is still visible to employers. I was also told to have my criminal record hidden from private employers, I need to have it exspunged. I thought they were both the same thing, but I am not sure? I live in Calfornia, is dismissal the same thing as expunged? Can I legally write that I have not been convicted of a crime when asked on a application? Thank You - Jessica