Switching implant brand - will they be similar?

Switching from a 310 Allergan implant to a 320 Sientra implant with a slightly reduced projection of 0.3 cm might not be noticeably different to the naked eye. It's a relatively small change in projection, and individual perception can vary. Factors such as your body type, existing breast tissue, and the surgeon's placement technique can also influence how noticeable this change is.

I hope this helps,
best of luck !

Dear Powerful425797,
breast implant type and sizing selection is a complicated process and requires a detailed consultation that includes a discussion of your goals, a detailed examination, and a lengthy discussion. But the decision will always start and end with the patient. When it comes to sizing, we have all of our patients find 3 photos of their desired breast size. We ask for naked breast photos because clothing can obscure the true size (push up bras). Next, we consult with patients and go over the photos and take detailed breast measurements during a physical exam. Next, we using a sizing algorithm to determine a range of implants that will work based on the exam and the measurements.Lastly, during the operation, we use silicone sizers in the operating room to see how the size actually looks in the breast. We sit the patient up in the operating room, while asleep of course, and compare the sizer result with their desired look photos. If it is too small, we start the process over with a slightly larger implant. We don't stop until we get the perfect match.Of all of my breast augmentation patients, every one of them has been happy with their size due to this detailed and meticulous process. You don't want to invest time and money into a result that is either too big or too small.You should discuss your concerns with a board-certified plastic surgeon and make sure that your surgeon understands your goals.
Daniel Barrett, MDCertified, American Board of Plastic SurgeryMember, American Society of Plastic SurgeryMember, American Society of Aesthetic Plastic Surgery

The new implants you are considering will give you a similar look to what you have now. The small change in projection and diameter will not be obviously different, especially in clothing. I encourage you to discuss your concerns with your surgeon.

I doubt you will be able to tell much difference. You did not state why you are changing implant companies, but Allergan has stood the test of time.

The change will be subtle, but possibly noticeable, at least at first.
There really isn’t much to discuss other than that.
Best,
Mats Hagstrom, MD