Breast aesthetics are highly subjective, based on opinion, expectation and individual goals. Probably the most considered question after the decision to have a breast augmentation is ‘what size implant should I choose?’. In considering implant size, there are many important aspects to consider. While size is important when considering an augmentation, shape is equally as important.

Implants come in many shapes, sizes, and textures. It can be incredibly confusing to consider all of them. While there can be significant brand loyalty by each surgeon, stick to brands that are backed by:

  1. Warranty – the manufacturer should be able to provide a warranty for the expected life of the implant. What happens if it ruptures? What happens if there’s a contracture? How long does it last? What does the warranty cover?
  1. FDA/TGA certification – They should be certified and used in other countries around the world
  1. Reliable tracking – Serial numbers/Lot numbers/microchips


Each manufacturer will have a selection of shapes, sizes (width/height/volume), content (filler or type of silicone), and surface texture.

The two general shape classifications are round, and anatomical. A round implant has the same diameter, and varies by its projection (see below), and volume. Anatomical, or teardrop implants, have a specific shape that is made to more closely approximate the shape of a breast. The shape of the implant usually varies in both width and height as well, to accurately fit the shape of the breast. Breast implant manufacturers will have their own variations to each of these implant types.

dr justin perron breast implants

Breast implant fill

The majority (if not all) breast implants sold in Australia will be filled with a cohesive silicone. Again, each manufacturer will have their own slight variations related to the gel to create a firmer or softer feeling implant. Being cohesive is important, as it prevents the silicone from leaking if the implant ruptures.

Surface texturing

There are two general types of implant texturing; smooth and textured. Textured implants tend to stay in place, and ‘velcro’ themselves to the surrounding tissues. Round implants do not, and are best used as a round shape only.

Decision making

The following factors each play a role in determining what implant is best for you:

  1. What look do you want? Fake or natural?
  2. What are your breasts like now (size, shape, symmetry)?
  3. What is your current body shape?
  4. Do you have any ptosis (sag, droop), and if so, how much?
  5. What is the amount and integrity of your breast tissue?
  6. What is your lifestyle and physical activity level?


Projection, or profile, refers to the distance an implant projects, or sticks out from your chest wall. Low projection implants don’t project as far as a high projection implant.

The decision on which implant projection is most appropriate for you, has to be taken in the context of your body shape, the size of your existing breast, and look that you are trying to achieve. Generally speaking, high profile implants will give a more fake look, while a moderate projection will favour a more natural look.

When choosing an implant profile, your existing breast shape is an important factor. There are a few key measurements that determine which implant profile will work best for your body, and should be discussed with your surgeon.


When considering size/volume, this is determined by your existing chest shape and width, and breast size. Round implants have a certain diameter, and this needs to fit on your chest wall. So considering an implant that does not fit your chest wall width, will not work for you.

Volume is not the most important consideration!! In fact, volume is secondary to shape when narrowing down the implant that you want. Because an implant is chosen based on yourspecific measurements, the size that fits you may not be appropriate for someone else!


This can be a big determinant when considering if you need a simple breast augment, or a lift (mastopexy). There are a few key measurements that need to be examined on your breast to make this differentiation. It is best to visit your surgeon in person to get an accurate assessment.


If you lead an active lifestyle, choose an implant that suits you. Being active doesn’t mean you can’t have implants, but you should select ones that aren’t going to hinder you. Big implants can cause problems such as bottoming out, rippling, rotation, and being palpable.

Trial Sizing

In addition to trying on an implant sizer, ask about the availability of a 3D simulation. Both can give you an idea of what the implant size feels like, before having surgery. While not 100% perfect, both methods approximate the look and feel of having implants.

As a rule of thumb, 150-200cc equal one cup size. This can vary depending on the bra manufacturer, and your own breast shape.

Be guided by your surgeon, and their own expertise in the area. At the same time, if you think an implant choice is too big, too small, or doesn’t seem right, get a second opinion! Make an informed decision without being pressured.

Guest post by Dr Justin Perron

Mater Private Clinic–South Brisbane

Phone: (07) 3010 3300

Book a consult with Dr Justin Perron here and get a voucher for $50 of the consultation fee. Mention this blog post and Breast Implant Advice when booking.