the intact device shell. the consequent, increased incidence-rates of medical complications (e.g. capsular contracture) precipitated faulty-product, class action-lawsuits, by the u.s. government, against the dow corning corporation, and other manufacturers of breast prostheses. the second technological development was a polyurethane foam coating for the shell of the breast implant; the coating reduced the incidence of capsular contracture, by causing an inflammatory reaction that impeded the formation of a capsule of fibrous collagen tissue around the breast implant. nevertheless, despite that prophylactic measure, the medical use of polyurethane-coated breast implants was briefly discontinued, because of the potential health-risk posed by 2,4-toluenediamine (tda), a carcinogenic by-product of the chemical breakdown of the polyurethane foam coating of the breast implant. after reviewing the medical data, the u.s. food and drug administration concluded that tda-induced breast cancer was an infinitesimal health-risk to women with breast implants, and did not justify legally requiring physicians to explain the matter to their patients. in the event, polyurethane-coated breast implants remain in plastic surgery practice in europe and in south america; and no manufacturer has sought fda approval for medical sales of such breast implants in the u.s. the third technological development was the double lumen breast implant device, a double-cavity prosthesis composed of a silicone breast implant contained within a saline breast implant. the two-fold, technical goal was: (i) the cosmetic benefits of silicone-gel (the inner lumen) enclosed in saline solution (the outer lumen); (ii) a breast implant device the volume of which is post-operatively adjustable. nevertheless, the more complex design of the double-lumen breast implant suffered a device-failure rate greater than that of single-lumen breast implants. the contemporary versions of second-generation breast implant devices (presented in 1984) are the "becker expandable" models of breast implant, which are primarily used for breast reconstruction. third and fourth generations in the 1980s, the models of the third and of the fourth generations of breast implant devices were sequential advances in manufacturing technology, such as elastomer-coated shells that decreased gel-bleed (filler leakage), and a thicker (increased-cohesion) filler gel. sociologically, the manufacturers of prosthetic breasts then designed and made anatomic models (natural breast) and shaped models (round, tapered) that realistically corresponded with the breast- and body- types of women. the tapered models of breast implant have a uniformly textured surface, which reduces the rotation of the prosthesis within the implant pocket; the round models of breast implant are available in smooth-surface- and textured-surface- types. fifth generation since the mid-1990s, the fifth generation of silicone-gel breast implant is made of a high-strength, highly cohesive silicone gel that mostly eliminates the occurrences of filler leakage ("silicone gel bleed") and of the migration of the silicone filler from the implant pocket to elsewhere in the woman's body. these implants are commonly referred to as "gummy bear breast implants" for their firm, pliant consistency, which is similar to gummy candies. the studies experience with anatomical soft cohesive silicone gel prosthesis in cosmetic and reconstructive breast implant surgery (2004) and cohesive silicone gel breast implants in aesthetic and reconstructive breast surgery (2005) reported low incidence-rates of capsular contracture and of device-shell rupture; and greater rates of improved medical-safety and technical-efficacy than that of early generation breast implant devices. breast-feeding cross-section scheme of the mammary gland. chest wallpectoralis muscleslobulesnippleareolamilk ductfatty tissueskin envelope the presence of breast implants currently presents no contraindication to breast feeding, and no evidence to support that the practice may present health issues to a breast feeding infant is recognized by the usfda. women with breast implants may have functional breast-feeding difficulties; mammoplasty procedures that feature periareolar incisions are especially likely to cause breast-feeding difficulties. surgery may also damage the lactiferous ducts and the nerves in the nipple-areola area. functional breast-feeding difficulties arise if the surgeon cut the milk ducts or the major nerves innervating the breast, or if the milk glands were otherwise damaged. milk duct and nerve damage are more common if the incisions cut tissue near the nipple. the milk glands are most likely to be affected by subglandular implants (under the gland), and by large-sized breast implants, which pinch the lactiferous ducts and impede milk flow. small-sized breast implants, and submuscular implantation, cause fewer breast-function problems; however, it is impossible to predict whether a woman who undergoes breast augmentation will be able to successfully breast feed since some women are able to breast-feed after periareolar incisions and subglandular placement and some are not able to after augmentation using submuscular and other types of surgical incisions. mammography a mammograph of a normal breast (left);a mammograph of a cancerous breast (right). the presence of radiologically opaque breast implants (either saline or silicone) might interfere with the radiographic sensitivity of the mammograph, that is, the image might not show any tumor(s) present. in this case, an eklund view mammogram is required to ascertain either the presence or the absence of a cancerous tumor, wherein the breast implant is manually displaced against the chest wall and the breast is pulled forward, so that the mammograph can visualize a greater volume of the internal tissues; nonetheless, approximately one-third of the breast tissue remains inadequately visualized, resulting in an increased incidence of mammograms with false-negative results. the breast cancer studies cancer in the augmented breast: diagnosis and prognosis (1993) and breast cancer after augmentation mammoplasty (2001) of women with breast implant prostheses reported no significant differences in disease-stage at the time of the diagnosis of cancer; prognoses are similar in both groups of women, with augmented patients at a lower risk for subsequent cancer recurrence or death. conversely, the use of implants for breast reconstruction after breast cancer mastectomy appears to have no negative effect upon the incidence of cancer-related death. that patients with breast implants are more often diagnosed with palpable—but not larger—tumors indicates that equal-sized tumors might be more readily palpated in augmented patients, which might compensate for the impaired mammogram images. the ready palpability of the breast-cancer tumor(s) is consequent to breast tissue thinning by compression, innately in smaller breasts a priori (because they have lesser tissue volumes), and that the implant serves as a radio-opaque base against which a cancerous tumor can be differentiated. breast mri of a patient with implant (blue) the breast implant has no clinical bearing upon lumpectomy breast-conservation surgery for women who developed breast cancer after the implantation procedure, nor does the breast implant interfere with external beam radiation treatments (xrt); moreover, the post-treatment incidence of breast-tissue fibrosis is common, and thus a consequent increased rate of capsular contracture. there is tentative evidence that women who have had breast augmentation, have worse breast cancer prognosis. the use of implants for breast reconstruction after breast cancer mastectomy appears to have no negative effect upon cancer-related death. there have been multiple reported cases of other adverse effects of mammography of women with breast implants; ruptures resulting from pressure exerted on the breast implant make up a majority of these cases. compression may also lead to pain or exacerbate already existing pain in the breasts. history vincenz czerny (1842–1916), a surgical pioneer in breast reconstruction. 19th century since the late nineteenth century, breast implants have been used to surgically augment the size (volume), modify the shape (contour), and enhance the feel (tact) of a woman's breasts. in 1895, surgeon vincenz czerny effected the earliest breast implant emplacement when he used the patient's autologous adipose tissue, harvested from a benign lumbar lipoma, to repair the asymmetry of the breast from which he had removed a tumor. in 1889, surgeon robert gersuny experimented with paraffin injections, with disastrous results arising from the breakup of the paraffin into smaller bodies following the procedure. 20th century from the first half of the twentieth century, physicians used other substances as breast implant fillers—ivory, glass balls, ground rubber, ox cartilage, terylene wool, gutta-percha, dicora, polyethylene chips, ivalon (polyvinyl alcohol—formaldehyde polymer sponge), a polyethylene sac with ivalon, polyether foam sponge (etheron), polyethylene tape (polystan) strips wound into a ball, polyester (polyurethane foam sponge) silastic rubber, and teflon-silicone prostheses. in the mid-twentieth century, morton i. berson, in 1945, and jacques maliniac, in 1950, each performed flap-based breast augmentations by rotating the patient's chest wall tissue into the breast to increase its volume. furthermore, throughout the 1950s and the 1960s, plastic surgeons used synthetic fillers—including silicone injections received by some 50,000 women, from which developed silicone granulomas and breast hardening that required treatment by mastectomy. in 1961, the american plastic surgeons thomas cronin and frank gerow, and the dow corning corporation, developed the first silicone breast prosthesis, filled with silicone gel; in due course, the first augmentation mammoplasty was performed in 1962 using the cronin–gerow implant, prosthesis model 1963. in 1964, the french company laboratoires arion developed and manufactured the saline breast implant, filled with saline solution, and then introduced for use as a medical device in 1964. fda approval in 1988, twenty-six years after the 1962 introduction of breast implants filled with silicone gel, the u.s. food and drug administration (fda) investigated breast implant failures and the subsequent complications, and re-classified breast implant devices as class iii medical devices, and required from manufacturers the documentary data substantiating the safety and efficacy of their breast implant devices. in 1992, the fda placed silicone-gel breast implants in moratorium in the u.s., because there was "inadequate information to demonstrate that breast implants were safe and effective". nonetheless, medical access to silicone-gel breast implant devices continued for clinical studies of post-mastectomy breast reconstruction, the correction of congenital deformities, and the replacement of ruptured silicone-gel implants. the fda required from the manufacturers the clinical trial data, and permitted their providing breast implants to the breast augmentation patients for the statistical studies required by the u.s. food and drug administration. in mid-1992, the fda approved an adjunct study protocol for silicone-gel filled implants for breast reconstruction patients, and for revision-surgery patients. also in 1992, the dow corning corporation, a silicone products and breast implant manufacturer, announced the discontinuation of five implant-grade silicones, but would continue producing 45 other, medical-grade, silicone materials—three years later, in 1995, the dow corning corporation went bankrupt when it faced large class action lawsuits claiming a variety of illnesses. in 1997, the u.s. department of health and human services (hhs) appointed the institute of medicine (iom) of the u.s. national academy of sciences (nas) to investigate the potential risks of operative and post-operative complications from the emplacement of silicone breast implants. the iom's review of the safety and efficacy of silicone gel-filled breast implants, reported that the "evidence suggests diseases or conditions, such as connective tissue diseases, cancer, neurological diseases, or other systemic complaints or conditions are no more common in women with breast implants, than in women without implants" subsequent studies and systemic review found no causal link between silicone breast implants and disease. the u.s. department of health and human services verifies the scientific, medical, and clinical data of medical devices. in 1998, the u.s. fda approved adjunct study protocols for silicone-gel filled implants only for breast reconstruction patients and for revision-surgery patients; and also approved the dow corning corporation's investigational device exemption (ide) study for silicone-gel breast implants for a limited number of breast augmentation-, reconstruction-, and revision-surgery patients. in 1999, the institute of medicine published the safety of silicone breast implants (1999) study that reported no evidence that saline-filled and silicone-gel filled breast implant devices caused systemic health problems; that their use posed no new health or safety risks; and that local complications are "the primary safety issue with silicone breast implants", in distinguishing among routine and local medical complications and systemic health concerns." in 2000, the fda approved saline breast implant premarket approval applications (pma) containing the type and rate data of the local medical complications experienced by the breast surgery patients. "despite complications experienced by some women, the majority of those women still in the inamed corporation and mentor corporation studies, after three years, reported being satisfied with their implants." the premarket approvals were granted for breast augmentation, for women at least 18 years old, and for women requiring breast reconstruction. in 2006, for the inamed corporation and for the mentor corporation, the u.s. food and drug administration lifted its restrictions against using silicone-gel breast implants for breast reconstruction and for augmentation mammoplasty. yet, the approval was conditional upon accepting fda monitoring, the