Some women may have flat or small breasts, or may be different in size, this problems could be correct by breast implants, the materials popularly used is the silicone Implants (balloon sheath with normal saline or silicone content), the alternative is fat transfer from the other sites of the body.
The silicone Implants is the balloon made from multiple layers silicone sheath with single lumen or double lumen (spaces), in single lumen the content may be normal saline or silicone gel or others material. In double lumen implant, the content is one normal saline and the other is silicone gel.

The operative site:
1. Areolar , the wound is around areolar 
2. Inframammary, the wound is below the breast (at skin fold)
3. Axilarry, the wound is at the axillar
4. Other, Endoscopic approach.

The implant place;

1. Submammary. The implant is place under the breast tissue above muscle.
2. Subpectoral. The implant is place under the pectoralis major muscle, above pectoralis minor and rib.

Type of Implants;

The implants is a balloon composed of outer shell made from silicone sheath(Multi-layers) and the content as follow;
1.The saline content, it was claim that because it is physiologic solution, it will be safe if leakage. In my experience the patients those are nervous from carcinoma accept this type of implant. But there is high percentage of leakage in a few years and the patient can not tolerated single breast. The problem is that what to do, if she decided to replace the leakage with the same type implant it may leakage again and what will be happen on the
other site. If she decided to replaces with the other type (silicone), how to do on the opposite.
2. The silicone gel content, this still controversy about safety, but many studies claimed that it is safe and many doctors used it. In my experience I never found rupture in the patient body spontaneously and no side effect. No cancer found.
3. Double lumen, one lumen is silicone gel and the other is saline content fiiled during operation, the problems will be the same as saline implant.

Complication and unwanted effects
1. Not good result; bad shape, malposition(misplace), size(over or under), scar, not equal size.
2. Infection.
3. Bleeding.
4. Capsular Contraction, the breast hardens later in month or years.
5. Capsular rupture and content leakage.
6. Others; risk from anesthesia, drug allergy, underlying diseases.

For more information please read at;

http://www.mentorcorp.com/index-aesthetics.htm

http://www.allerganandinamed.com/jump/mcghan_home.html

http://www.sebbin.com/

http://www.eurosilicone.com/