Would there be a significant visible size difference if I went from a 450cc to a 550cc Saline Moderate Plus implants?

Hello and thank you for your question. Honestly, a formal in-person evaluation would be needed to determine the best treatment. There are several reasons for this:
1) Bra sizes vary based on the clothing store (for example, Victoria's Secret tends to upsize everyone by a whole cup size)
2) Most women do not wear the proper exact fitting bra size for their bodies
3) The exact volume (in cc) needed to change cup size is different for different body types (e.g. 32A to 32D requires a different implant size than 38A to 38D)
4) Be careful NOT to fall into the trap most women do- they see a certain implant size (e.g. 285 cc) or perhaps their friend had a certain size, and they want or request this or another size based on that. Everyone's body is different- 285 cc implants on your friend might look VERY different than they would on you. Be very careful not to make this mistake, because the goal is to find the right size and shape for YOU- for your particular body and your breasts.

Because of those multiple factors, and because it is KEY to fully evaluate your breasts in person to make a full set of precise measurements to select the proper implant for you (incorporating factors like amount of breast tissue, implant type, base width, projection, etc), answering your question really would need a formal personalized consultation- to say anything before that would simply be guessing, which would be both unfair and unhelpful to you. Also, just FYI, each surgeon's measurements are slightly different, so numbers, experience, and overall aesthetic from one surgeon aren't necessarily the same as those from another surgeon!

Your breasts are such a KEY area of your body and your femininity- therefore, you should ONLY trust an experienced aesthetic plastic surgeon. As such an expert, I have had extensive training and experience with complex aesthetic surgeries under a multiple world-renowned experts in the field. I’d recommend for you to setup a formal consultation with me (or another plastic surgeon who is extremely comfortable with aesthetic plastic surgery procedures) for a formal consultation to thoroughly discuss your surgical goals, undergo a formal examination, evaluate all your options (surgical and nonsurgical), and decide on the best procedure(s) and type of anesthesia for your specific case. I hope this helps!

Dr. Donald Groves
Aesthetic Plastic Surgeon

This is always a very difficult question to answer because cup sizes vary with the bra manufacturer and plastic surgeons do not agree on the number of cc's equivalent to a cup size.  Some say from 130 - 150cc's; others, 200cc.  Trying on implant “sizers” of 450cc, 550cc, and overfill size during a preop visit while wearing a tight t-shirt, sweater, bathing suit and any other clothes you typically wear will help you and your surgeon choose the optimal implant.Kenneth Hughes, MD, ABPS Board Certified Plastic SurgeonLos Angeles, CA

Thanks for your question. There is no rule that tells how much volume makes a cup size breast difference For a woman with a slight build, it can be as little as 100 cc. For a larger woman, a cup size can equal 250 cc if not more. Your prior augmentation, you used a 420 which was filled to 450 cc. So if you use a 550 cc implant, what would be the final volume? Most people suggest that 150 cc equals one cup size for an average woman's breast, so with an implant volume that can be between 550 to 660 cc, your result could easily be a cup sized bigger. So to directly answer your question, yes you could easily look bigger. The details matter. good luck.

Most patients need to go up 150cc from their existing size to see a noticeable difference.  150cc is 1/2 a can of soda, so use that as your frame of reference.  You may want to cheat up more towards a 600cc fill volume if you want to see a cup size change.  I hope this helps.

Adding another 100 cc's will probably put you into a D or full D size. It probably will not give you a full cup increase in size. Bras are not made to a standardized size, so you may find you wear different sizes in different styles.

If you would like to see a modest increase in breast fullness 100 cc might indeed meet your goals. Since you are replacing your implants anyway this would be a time to consider upsizing if you feel this would benefit you. Typically it requires at least 100 cc or greater to notice a difference. Discuss your thoughts with your plastic surgeon during your consultation and pre-operative visits to get a better idea of how best to achieve the look you desire.

this would likely be a small difference.  you may or may not notice it.  I would discuss the plan with your surgeon.

Yes, it is likely that you will see a significant difference with about 100 cc increase in breast implant volume.  Of course, the degree of difference seen will vary from one patient to another, depending on factors such as body "type".

***The much more important question with be: which breast implant (volume and profile) will be the correct choice when it comes to  achieving your desired outcome when it comes to breast size/shape/symmetry…?  Online consultants will not be of much specific help to you in this regard.

Generally speaking, the best online advice I can give to ladies who are considering revisionary 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. I have found that the use of words such as  “natural” or "D or DD cup” or "significant difference" etc means different things to different people and therefore prove unhelpful.
 Also, as you know, cup size varies depending on  who makes the bra; therefore, discussing desired cup  size may also be inaccurate.   

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).  Viewing the patient's chest wall in the upright and supine positions, with temporary sizes in place, help select  the best breast implant size/profile for the specific patient.
 Best wishes.