Can 350cc Breast Implants Be Filled to 375cc?

The implant manufactures have a recommended range for filling of saline implants. Assuming your implants are not inflated to maximum recommended volume, it should be a safe and relatively easy procedure to add 25cc of saline. I, however, would not recommend this procedure. A 25cc increase in volume is small and would not provide substantial added augmentation. It therefore is hard to justify the costs and potential risks for even this relatively minor procedure.
I hope you are not dismayed by this answer. Best wishes to you.

I assume you are referring to saline implants. Saline implants are produced with a recommended fill volume range. The ranges vary for different styles as well as manufacturers.
For example, some implants state: 350 + 50  -00. This means it can be filled from 350 to 400cc

In contrast to gel implants, saline implants will have a recommended "fill volume." The surgeon therefore has a range of fluid that can be placed into the implant. You should receive an implant card after your procedure which has the size of the implant and how much fluid was placed into the implant by your surgeon. Filling the implant to the maximum recommended volume will decrease rippling in the implant and is commonly practiced. However, "overfilling" the implant beyond the recommended range can void your implant warranty so be sure and check with your surgeon before the implants are placed. Generally, a "350cc" implant can be filled to "375cc's."

The recommended fill levels for all saline filled breast implants are determined by the manufacturer. For example Allergan Natrelle saline style LP-350 implant is a 350cc implant with a suggested fill range of 350cc to 370. It would be possible to fill this implant to 375cc's. These fill sizes are not absolute. Some doctors overfill implants to achieve a desired result.

All saline breast implants have a recommended manufacturers fill range. The general rule is that implants can be filled to 10% above the that range. As you fill an implant beyond these recommendations, you can experience scaffolding along the edge similar to rippling. You never want to under fill an implant. This will increase the rippling and deflation rates.

Implants are usually filled to the recommended maximal fill volume. If you mean can they be overfilled? Yes, some surgeons over fill implants to keep the base of the implant the same but to accommodate for differences in volume. An overfilled implant may feel a bit firmer than normally filled implant

A 350 cc saline filled implant can and is frequently filled to 375 cc.  This can give a little more projection and roundness to the implant.  With the saline filled implants as you  add more to the implant they can develop a bit of scalloping along the edges. 

Saline implants have a minimal and maximal fill volume designated by the manufacturer. It is recommended that the implants be filled to the max if possible. 350 cc implants can definitely be incresed to 375. The question often arises if the implanst can be overfilled to max or even above the max when they are already in. There are several options at that point and you should discuss those options with your plastic surgeon.

The key to attractive natural breast implant augmentation is to match your body with the best implants that would fit and enhance it. Although anybody can strong arm and stick an implant in a woman's breast - we have all seen the results of such "augmentations".
It is BEST to pick an implant that would be totally covered by your breast tissue (which would better hide the ripples ALL implants have), that based on your chest wall would fir on the flat, front plateau of your chest (and not fall to the sides), that would have less rippling and leak less often (avoid textured implants, especially over the muscle) among others.
Personally, I would NOT operate on you if I knew your husband was pushing you into having this done. Cosmetic Surgery is a VERY personal decision which should NEVER be done for anyone else.

I assume you are inquiring about saline implants which are filled with saltwater solution. In my practice I offer the Mentor saline implants and they come with a manufacturer recommended minimum and maximum fill volume. For the implant size of 350cc for example the recommended fill volume is up to 400cc. I am usually advising my clients to have the maximum recommended fill volume so you have less ripples in the implants. Sometimes the fill volume is different for clients who have asymmetry and need adjusting for volume.