Unlike in Europe and South America, implants are made by only two companies in Canada and these products are very strictly regulated. There are many different kinds of implants. These differ based on their material fill (water or silicone), their surface texture (smooth or textured) and their shape (round or anatomic).
Saline versus Silicone
In the 1980s there was a great concern about the safety of silicone implants and the possibility of an association with auto-immune diseases such as rheumatoid arthritis and lupus. These concerns have since been dismissed. Silicone is one of the most studied medical product on the market and is considered safe. Saline implants are still available and can be used for breast augmentation if the patient has enough tissue to conceal the implant as it does tend to ripple with time. For this same reason, silicone implants are most often used for breast reconstruction.
Smooth versus Textured
The surface of implants can be either smooth or textured (like velcro). This effect helps to keep the implant from sagging and also can help to prevent increased scarring around the implant. The disadvantages of texturing include firmer implants that are immobile.
Round versus Anatomic
Implants can be round or shaped like a breast (called anatomic). Anatomic implants are all textured as they must stick to the chest wall in the correct orientation to avoid rotation. Round implants can be either textured or smooth. The decision on which kind of implant to use should be a discussion with your surgeon as each of these different kinds has advantages and disadvantages.
For more on breast implant related procedures