When it comes to round shaped implants vs. tear drop (anatomic/contoured) implants, a published study found no significant difference between the two. In fact, quite unexpectedly, the round implants were found to be more "anatomic" or "natural" than the tear drop shape (anatomic) implants while in the laying position. The shaped implants cost significantly more, without a commensurate benefit. Furthermore, there has been reported a 14% rotational deformity, that is the implant can shift position, causing the breast to appear misshapen. For these reasons, I rarely use tear drop implants, except in cases of difficult breast reconstruction.