Is it possible to have a lip piercing forever without having any dental problems while wearing bioflex jewelry?

Possible VS Probable: The lips move tens of thousand times a day. As a result, even a small jewelry comes in contact with the tooth and/or gums. While it may be "possible", over time, it is not probable that anything harder than the soft inner lip tissue will not damage the tooth and gums.

Possibly: Lip piercings can cause chipping of the teeth, this can also be seen with tongue rings.

Anything is possible: But why take the chance. If its something you feel very strongly about, then it's a conscious decision you have made and the complications that result are something that have to be dealt with. Don't mean to lecture, rather sincere advice. Hope this helps.