 Both silicone gel and saline breast implants may rupture, or existing ruptures   may be exacerbated, during compression for screening mammography. In fact, during   a 9-year period, at least 33 cases of implants rupturing during mammography   were reported to the Food and Drug Administration and at least 17 more were   reported in the medical literature, according to agency researchers. 

 It is unclear whether compression ruptures the implant itself or the scar   capsule, converting an intracapsular rupture into an extracapsular one. Regardless,   over time as an implant remains in place, pressure resistance and implant strength   decrease, which places older implants at greater risk of rupture. Capsular contracture,   capsular thickness, and calcification can also increase risk. 

 Because implants can decrease the amount of breast tissue that is visual on   mammography by about 80%, modified positioning techniques, such as the Eklund   or pinch technique, are often employed. Such methods, which involve pulling   the breast tissue away from the implant and compressing the tissue with up to   45 pounds of force, need to be employed extremely carefully to avoid implant   rupture. 

 Brown SL, Todd JF, Luu HMD. Breast implant adverse events   during mammography: reports to the Food and Drug Administration. 