How to get all parent comment from a thread

[tnm0113]

Hi all, I have a thread like that: Submission |--Comment 1 ---|--Comment 2 ------|--Comment 3 If i have id of comment 3, how can i get the above ones. I know i can get parent recursively but i can't find property to distinguish between comment and submission. And do we have better way to do that ? Tks