I am having a hard time choosing between 345cc and 365cc silicone high profile.

Hello and thank you for your question.  The
best advice you can receive is from an in-person consultation.  Fortunately 345cc and 365cc are very close in size.  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.   
Best wishes and good luck.
Richard G. Reish, M.D.  FACS
Harvard-trained plastic surgeon

Dear Brittnyc1990,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, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

Make sure you and your plastic surgeon are on the same page with your goals and preferably do pre-operative sizing if you have not already.Then, if you feel comfortable with your surgeon (who should be a real Plastic surgeon certified/eligible by the American Board of Plastic Surgery and experienced in cosmetic breast surgery), trust them to make the decision on what is going to fit your body the best and give you the best result.Try not to get too hung up on the numbers as all patients are different.  Also consider that a 20 cc difference between the 2 sizes you are considering is the same as only 4 teaspoons of volume, so a fairly minimal difference between the two.Thank you.