415 or 450cc silicone implants HP?

Thank you for
your question.
Please know that it is a common misconception that implant size correlates
with the bra cup size. A bra-cup size itself requires many measurements to
describe it.
Bra sizes vary among manufacturers, and they can label the cup size by any
designation they choose. So a C will be a D for another. Additional factors, such as demi and full
cup coverage, specific fabrics, padding, and elastics, can all affect the fit
of a bra.
If we consider all things being
equal – i.e., you get a bra from the same manufacturer and of the same style, -
then I think you might find it helpful to know that a study by Dr. Bengtson and
Dr. Glicksman titled “Standardization of Bra Cup Measurements” has shown that
the average implant volume required to increase the cup-size by 1 size is equal
to 205 ccs. It was also found that normally breast augmentation increases the
cup size by 2. However, it is also important to consider the profile as even a
smaller implant with a high profile can increase cup-sizes by the same amount.
Now, it may be helpful to do
bra-sizing trials with the bra of your choice when you go in for a
pre-operative consultation with your board-certified plastic surgeon. Now,
although you give importance to
cup size designation, what should matter most is that the implant looks good
aesthetically and that the chosen bra fits and feels comfortable.
The implant has
to fit YOUR body dimensions. The more you deviate from the proper fit,
the more fake your breasts will look.
Surgeons use what is called
tissue-based planning. The planning takes into account the effects of implants on tissues over time,
risks of excessive stretch, excessive thinning, visible or palpable implant
edges, visible traction rippling, ptosis (Sagging), and breast tissue wasting.
To determine the final implant size, breast measurements
need to be made:  base-width, breast skin
stretch and nipple-to-Inframammary fold distance. The combination of these
measurements will help determine tissue coverage and the required implant
volume to optimally fill the breasts. If the skin covering your breasts is
stretchy (>2 cm), or if your nipple-to-inframammary fold distance is greater
than 9.5 cm, then more volume is needed for the optimal fill.
So please focus more on having full and natural
looking breasts rather than trying to fit into a particular bra-cup size.  That being said, a 45 cc difference in implant size does not make a noticeable difference. At least over 50-100 cc is needed to allow a noticeable difference.If 450 cc is slightly below the limits of your breast frame, then you might as well go with the 450 cc since some patients do not in fact regret not having gone with a bigger choice when given the option.
Having all this considered, share all your motivations for surgery, expectations
and goals with complete honesty to avoid miscommunication and post-operative
concerns/regrets. Be as specific as you can about what you like regarding your
breasts and what you don’t like. If you trust your surgeon and their judgment and the
decision-making method used to choose the implant size, then you should be in
good hands.
Hope this helps.

Wow, you had Vectra imaging and still can't make up your mind. Have you tried on the actual implants with a tight bra. My office has over 100 breast implants and a Mentor sizer kit to help you make an informed decision. Reviews of photographs before and after are also helpful to determine the probable best size for you. Sounds like you have a board certified ASAPS plastic surgeon. Good luck....

Hello and thank you for your question.  The
best advice you can receive is from an in-person consultation.  The size,
profile, and shape of the implant is based on your desired breast
size/shape, your chest wall measurements, and soft tissue quality. 
This decision should be based on a detailed discussion with
equal input from both you and your surgeon.   Make sure you
specifically look at before and after pictures of real patients who have
had this surgery performed by your surgeon and evaluate their
results.  
Best wishes and good luck.
Richard G. Reish, M.D.
Harvard-trained plastic surgeon

Hello. Trust your surgeon. The larger implant that is suitable for your frame based upon your breast and chest dimensions is usually the best choice.   Good luck
DrBurnett#realself100

If you have thought of those two implants, you can always do a baggy test with  the bra you want to fit. Implant volumes alone are difficult to predict cup size.

Thank you for the question.   There is no accurate/reliable/predictable correlation between size/profile breast implant utilized and cup size achieved. For example, I do not think that the generalizations of "200 cc equates to 1 cup" hold any validity or are helpful in any specific or practical way.  In my practice, I ask patients not to communicate their goals, or evaluate the outcome of the procedure performed, based on cup size references.
Ultimately, careful communication of your goals (in my practice I prefer the use of goal pictures, direct examination/communication in front of a full-length mirror, in bra sizers, and computer imaging)  as well as careful measurements (dimensional planning) will be critical.
 ***Given that your surgery is coming up soon, I would suggest that you spend additional time communicating your goals/concerns directly with your plastic surgeon, preferably prior to the date of surgery.  It will be important for many reasons, that you feel comfortable that you and your plastic surgeon are on the "same page" prior to proceeding.
Generally speaking, the best online advice I can give to ladies who are considering breast augmentation surgery ( regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully. Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals with your plastic surgeon. This communication will be critical in determining breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. For example, 
I have found that the use of words such as “natural” or "D  cup” etc means different things to different people and therefore prove unhelpful.
Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup size may also be inaccurate. Again, the use of computer imaging has been very helpful during the communication process, in our practice.
3. Once you feel you have communicated your goals clearly, allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals. Again, in my practice, this decision is usually made during surgery, after the use of temporary intraoperative sizers.
I hope this (and the attached link, dedicated to breast augmentation surgery concerns) helps. Best wishes.