Breast implants (both companies Allergan and Mentor) makes extremely good implants with durable silicone elastomer shells. I have met and even worked with the biomedical engineers involved in testing and production of the implants. When the "test" each implant they fill them up to something at least as large as basketballs even for very small implant sizes to test the "burst strength". At some point they will rupture but it is like filling a water balloon ten times over... The silicone shells are much stronger than you think. So as I tell my patients, you are not going to burst your implants from hugging, or activity, or even mild trauma. I have had a patient with a airbag deploy in a minor accident and her implants were fine. It is theoretically possible to rupture from pressure, but the most common reason for saline deflation is spontaneous and it just happens in a small degree of patients over time (approximately 1% per year). I hope this helps!
Sincerely,
James F. Boynton, M.D., F.A.C.S.