 The objective of the Contour Profile Gel Study, which started in 2002 is to determine the safety and effectiveness of the Silicone Contour Profile Gel Mammary Prostheses in women who are undergoing primary breast augmentation, primary breast reconstruction, or revision. In the duration of this study patients are required to have follow-up visits 10 weeks post-surgery and every year after surgery through the 10th year of completion. Additionally, out of the approximately 1000 patients enrolled in the CPG study, 400 have been randomly selected to have MRI scans at their 1,2,4,6,8,and 10 year post-surgery visits. Protocol changes now require all patients in this study to have MRI scans at years 6, 8, and 10. 