Max Number of Cc's when Adding More Saline to Implants?

Usually there is a a small amount of overfill that is allowed by the manufacturers, about 30cc in most cases. This makes little difference if the breasts are very different in appearance.
Exceeding this amount can result in deflation or rupture of the implant, or in a deformation of the appearance of the implant since it is made for a specific volume, and not to be excessively overfilled.
Dr. Canales has pointed out that implant deflation and weight changes can change breast appearance, as can capsular contracture, drooping or loss of breast tissue over time.
If you want to attain the very best result, you may want to have your situation reevaluated again by an experienced plastic surgeon rather than to try to add more saline to an 8-year old implant.

It is not a good idea to add volume to existing implants. The best option would be to exchange your current implants for new implants. You may also want to consider changing your saline implants to silicone implants. In either case, make sure you have a good discussion with your surgeon before embarking on yet another breast surgery. Good luck.

Breast implants have a recommended fill volume and these are relatively limited.
Although you can fill the implant beyond it's recommended range, it will distort the implant and likely produce an unwanted or distorted appearance, This may cause peripheral scalloping and an overly round appearance.
There are many reasons why the breasts may be different in size and these include implant leakage on the smaller side or breast gland growth on the larger side. These would require two different approaches to achieve the best result. Furthermore at 8 years, you may want to consider changing the implants.
Discuss these with a surgeon who will best be able to provide you with the optiuons for management.

Hello,
Old implants will eventually rupture. Adding saline to an old saline implant voids the warranty, so there would be no free replacement if it does break. It also doesn't give you much as most saline implants have relatively small fill tolerances. Finally, going in to operate has a small chance of leading to an infection, so with so little to gain, it makes little sense.
Consider having new implants (or just one implant) placed.

If you have implants that are 8 years old, they already have some structural fatigue. They may rupture while trying to add fluid, or shortly thereafter. It does cost money to buy new implants, but compared to the overall cost for surgery it is not that much, and you are ensuing the risks of surgery to even consider adding volume. To risk needing another operation in a short time is not worth the possible cost savings from recycling your implants.

Texas,
Your saline implants do have a maximum fill amount that is determined by the manufacturer. Your surgeon may still have the records and/or you may have been given documents telling you exactly what type of implants you have and how much saline was added to them. Of course, your scenario begs the question of why one breast is now larger than the other. This could represent a leak in one of the implants, in which case, it would need a replacement anyway. See a board certified plastic surgeon for some guidance. Good luck!

Your implants are old, but still good. Trying to add fluid at this stage of the game is a bit risky on several fronts, compared to the expected improvement. Additionally, the amount that may be added to the smaller side, and conversely, removed from the larger side may be minimal or none at all depending on how much was initially placed. Your doctor may not even have the records anymore, as many states only require holding them for 7 years.
My recommendation is to consider two possibilities. First, if you can live with the asymmetry, then do so- it is safest, and cheapest. Secondly, if you don't/can't do #1, consider implant exchange. You now have some nice options with silicone!
sek

Each saline implant has a recommended range of volume fill from a minimum to a maximum. Once to have filled to maximum volume, further filling is not recommended nor very helpful in increasing the size of the breast. It merely increases the risk of leakage and the firmness of the implant.To change the size significantly, you might need to go to a different style or diension of implant. Getting an exact symmetry is difficult but you might be able to get a better match by varying the width, the projection or the style. Another option in breast asymmetry is to vary the breast tissue to match and maintain the same implant. Sometimes surgeonhave to perform an augmentation-reduction-mastopexy in the same breast to achieve symmetry.

There are a few possible explanations for you to suddenly have one breast larger than the other 8 years after implants. I am assuming they were close when you first had them.
1. Could you have a deflation (total or partial)? In that case adding saline to a defective implant won't be an option. Discuss this possibility with your surgeon.
2. Is your weight the same as 8 years ago? If you have put on some weight, sometimes your native breasts grow and any asymmetry you had before can be accentuated by the weight gain.
Adding saline to one implant may correct the volume difference, but it may not correct any differences in shape. You could need a mastopexy or other adjunct surgery to try to maximize symmetry.
Consult with a board-certified plastic surgeon or two and they should be able to help you narrow down the causes and give you some options for surgery. Best of luck.