A breast implant is a medical prosthesis used to correct the size, form, and feel of a woman’s breasts in post–mastectomy breast reconstruction; for correcting congenital defects and deformities of the chest wall; for aesthetic breast augmentation; and for creating breasts in the male-to-female transsexual patient. There are three general types of breast implant device, defined by the filler material: saline, silicone, and composite. The saline implant has an elastomer silicone shell filled with sterile saline solution; the silicone implant has an elastomer silicone shell filled with viscous silicone gel; and the alternative composition implants featured miscellaneous fillers, such as soy oil, polypropylene string, et cetera. In surgical practice, for the reconstruction of a breast, the tissue expander device is a temporary breast prosthesis used to form and establish an implant pocket for the permanent breast implant. For the correction of male breast and chest-wall defects and deformities, the pectoral implant is the breast prosthesis used for the reconstruction and the aesthetic repair of a man’s chest. (See: gynecomastia and mastopexy)