When you have used neither AP nor EAD, you're fine until current TN expires.
http://blog.wenxuecity.com/blogview.php?date=200802&postID=7147
BTW, a denial of I-130 by a USC is rare. 
It depends - 回复:紧急救助: 有TN签证,如果申请绿卡失败后,是否TN也失效了?
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                    谢谢pjiang大师!!
                     -cdmm- 
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                        03/09/2010 postreply
                                                07:34:15