What you should know about silicone
Every day, most of us, use silicone in any of its forms. Due to their unique properties, the silicone have been used widely in products during almost 50 years. In one of its forms, the silicone can prevent the formation of foam, reason by which will be able to find it in mixtures packaged for pies and puddings. Many people regularly consume it in drinks, sodas and in antacids, as simeticona. Simeticona is even used in anticolic formulas for babies.
Another silicone form, dimeticona, is popular in products of personal use. In lipsticks, and lotions for the hands, the silicone acts like protective hydrating. Tanning, repellent lotions against insects, after shave lotions, shaving creams, deodorants, shampoos, dyes and sprays for the hair, all normally contain silicone in some of their forms.
Sheets, clothes and towels, acquire their smooth tact once are dealt with silicone. The silicone also is used to repel the water in umbrellas, raincoats and in waxes. The labels are taken off more easily if they are dealt with a silicone film. The silicones also are important for the treatment of the water and the manufacture of memory chips for computers.
Silicone and medicine
For more than 50 years, the silicones also have been used with medical pourposes. No other material has demonstrated to be so biocompatible, trustworthy, flexible, soft and easy to sterilize like silicone. The silicones are resistant to the chemical decomposition, even in severe conditions as it would be the contact with gastric acids. By those reasons, the silicone is the medical product material more commonly used to be implanted in the body.
What is the silicone?
The silicone is a chemical compound family that has many common applications. You probably use daily, without at least realizing, stuff that contain silicone.
The silicones are made from the silica natural component of the sand, the quartz and rocks. After the oxygen, the silicon is the commonest present element in the terrestrial crust, and like with oxygen, as much the life animal as the vegetable depends on him. When it is combined with oxygen, carbon and hydrogen, the silica is transformed into silicone. Depending on how their molecules are distributed, the silicone can have a great variety of forms, including dusts, gels, oils, and elastomers.
The intention of this information is the one to respond to typical questions on silicones. The information that appears here bases on an ample scientific research. At the end of the same one it will find a list of the main sources of reference.
This text will provide a general vision about the silicones, how they are used and why the professionals of the medicine consider that its use is safe and effective.
This text does not try to replace the medical advice about the risks and benefits associated with implantable medical products. If it has any question, donīt hesitate in consulting your doctor.
The medical uses of silicones are very extensive. The lubricant qualities of a silicone form make ideal like biomedical coating. The silicone is used to have surgical needles and threads with suture; also it is used to have the interior of syringes, and bottles to contain intravenous blood and medicines. It will even find silicone protective coatings in pacemakers and cardiac valves.
The elastomers of silicone are the biomaterial of election for an ample medical product range. Pacifiers for children usually are silicone elastomer facts. Norplant, a contraceptive product recently approved by the FDA, acts by means of implantable silicone tubes that release the medication.
The silicone lenses give back the vision to blind eyes by cataracts. Shunt of silicone helps people who undergo of glaucoma or hydrocephaly. Silicone tubes connect to the patients with kidney problems to the dialysis machines. Silicone membranes are used in machines for treatment of blood in patients with cardiac problems. Artificial silicone joints are used in patients with orthopedics problems. Dental products, medical medicines and instruments, all use silicones. In plastic surgery, you can implant them in the face, breast, tissue expanders and silicone bandages facilitate the reconstruction and physical improvement.
About the security
Because the silicones are so widely used in the daily life and in medicine, a rigorous scientific examination is mandatory to answer all questions arising about their security. Recently, with all the attention of the media dedicated to breast implants, the main questions were about two specific diseases: breast cancer and autoimmune disease.
Can the silicone cause some of those diseases in human beings? A great amount of scientific evidence has been compiled from the million and a half women who have breast implants, and it is continued compiling. There is no reasonable evidence that suggests silicone causes any type to it of cancer or autoimmune disease.
What does clinical studies tells
The only form to determine if the silicone is related of some way to diseases of human connective tissue is to carry out great clinical studies. So that they are scientific and accurate, those studies must make a comparison between a great number of random selected women and who have received the implant (not just those who had already has been diagnosed any disease) and another similar group that never has taken an implant, to see if one of the groups presents/displays a superior rate of upheavals. One of the first controlled studies of that type was carried out in the University of Texas, Houston. From 1986 to 1992, the study made a pursuit of 603 women who had happened through a mammary reconstruction: 250 patients received you implant mammary silicone gel fillings, and to 353 patients a mammary reconstruction with its own tissue. The study demonstrated that between the women with an implant did not have a greater risk of undergoing diseases of the connective tissue that in those not implanted.
In two different studies presented in 1993 in the Annual Meeting from American College of Rheumatology, more proofs were shown in which any relation between the silicone mammary implant and the connective tissue diseases could not be demonstrated. In one of the studies, investigators of the University of Toronto, compared 200 women with mammary implants with 100 women without them and in addition also they compared those women with 29 women who had experienced a rupture of the implants. Neither studies showed significant differences between the implanted women (even those with you implant broken) and the women without implant, that could suggest some connection between a silicone mammary implant and any disease of the connective tissue.
A declaration prepared and published by a committee formed by eminent doctors, including plastic surgeons, specialist in rheumatology, and the Medical American Association affirms that no test done can relate a silicone implant with the diseases.
The Mayo Clinic contributed with more evidences in support of the studies of Los Angeles and Alberta, Canada. Their investigators studied to more than 1,700 women than had received a silicone gel filled mammary implant for breast reconstruction, during a period of 29 years, and they did not detect any increase of the in incidence of breast cancer.
Interferences on conventional mammography
Although the studies have demonstrated that the silicone mammary implant do not produce breast cancer, women and their doctors would have to consider certain special mammographic considerations. Because you implant interfere with the conventional mammography, you and the attending physician must inform to the radiologist about the implant when soliciting a diagnostic mammography. The radiologist must have experience with the habitual techniques of mammographic displacement (like the Eklund technique) that allow to visualize the totality of the mammary tissue around the implant.
About silicone and the autoimmune disease
The main reason by that the silicone is used so widely with medical purposes is that it is considered inert and biocompatible within the organism. In spite of that medical consideration, some recent information appeared in the media relates the silicone as the cause of autoimmune disease of the connective tissue. The upheavals of the connective tissue happen independently in the general population, and many of them happen frequently in women, including rheumatoid arthritis, systemic erythematous lupus and sclerodermia. Some women who also undergo an upheaval of the connective tissue will receive a mammary implant, and it does not mean that those implants have caused them those upheavals.
The immune system is the natural defense of its body against infections and diseases. The antibodies protect your health attacking the strange substances. The specific antibodies respond against specific antigens that recognize as strange and they destroy them.
What is an autoimmune disease?
Autoimmune disease is a general term used to describe to an immune system that responds to the defensive substances of their own body. The upheavals of the tissue can happen like result of that disease. Those problems happen habitually in the general population.
The idea that the silicone can cause disease autoimmune is just a theory. Statistical evidences based in studies between groups of women who take you implant and women who develop to autoimmune disease, strongly suggest that this theory is erroneous. So that the silicone caused what the theory suggests, would have to do much more that simply to shoot an immunological answer, also it would have to cause that the normal immunological answer became against its own organism.
The causes and the progression of the upheavals of the connective tissue well are not well understood and their symptoms can vary. The rules for their diagnosis are not completely clear. The alteration of the immune system only one of the several manifestations that frequently appears in the upheavals of the connective tissue. Other main factors associated are the genetic predisposition or familiar history and the condition for being woman.
Investigation on silicone and autoimmune disease
Investigations demonstrate that there are no tests that prove the silicone causes to autoimmune disease. Three types of medical publications show the results of the investigations carried out on silicone and immunological answers:
· The Studies of Cases simultaneously review the symptoms of one or several patients.
· The Studies of Laboratory with animals, provide data on security.
· The Clinical Studies on humans directly gather data of the patients and, often, they compare the resulting data with the expected ones in the general population.
What does cases studies tells
The first information on human adjuvant disease in women who had undergone cosmetic breast surgery arrived from Japan. The incorrect medical method of breast surgery cosmetic employed in those cases included the injection of great volumes of diverse substances of unknown purity, including liquid silicone, paraffin (liquid wax) and petroleum jelly. The studies of those cases, a total of 60 women, suggested that injections served them like adjuvant making worse the symptoms of a preexisting disease. It does not have to surprise to us that the direct and voluminous injections of substances of unknown purity that those women received could make worse their previous conditions.
Other studies of more recent cases have reviewed women with upheavals of the connective weave and that also took you implant mammary of silicone, without showing no test that it related the upheavals with you implant them. The studies of cases in themselves do not constitute a test either is to hope mainly that there are some coincident cases of disease of the connective weave in women with you implant mammary, considering that of one to two million women have silicone mammary implants, and that women are much more prone that men to develop upheavals of the connective weave.
What does laboratory studies tells us
Articles about the immunological answer in animals of laboratory have been published referred to silicone in their different forms. Some studies have demonstrated that the silicone can cause an immunological answer (not of autoimmune type), when it has been combined with an adjuvant well-known, different from silicone. Other studies affirm that the silicone, in combination with an adjuvant one, whose effect would be to increase the immunological answer, does not even cause this response. The results of the studies with animals have been conflicting and say little about the answer in humans.
About silicone and the breast cancer
The silicone materials have been exhaustively proven in laboratory studies. Those studies verify that silicone do not cause cancer in human beings. Those studies are very important and constitute a key test about the security of the product. However, the clinical studies are still more important that those who monitor the human health directly. In that case, the most important studies are those made on women who have taken a breast implant for several years.
Clinical investigation on silicone and breast cancer
The type of breast cancer that occurs in the human beings develops in weaves with high density of ducts and glands and can be scattered by all the body. One of each nine women in North America develops a breast cancer during its life. If silicone would increase the probability of developing breast cancer, it would be expected that the studies demonstrated that the women who take a mammary implant are more prone to develop cancer that the women who never have taken them. And it is not true. The results of huge studies confirm that the breast cancer does not happen more frequently in women than have a mammary implant that they that do not have them.
A study carried out in Los Angeles in 1986 at the University of Southern California that was published in the Journal of Plastic and Reconstructive Surgery, investigated more than 3,000 women that received a silicone mammary implant between 1969 and 1980 and did not detect a greater risk of breast cancer after the mammary augmentation.
In 1992 a follow up of 5 years done on that same group, confirmed the original findings. In 1992 a study in the University of Calgary, Alberta, Canada that was published in a the New England Journal of Medicine, investigated to more than 11,000 women that had received a silicone mammary implant between 1973 and 1986 and either did not detect any increase in the risk of developing breast cancer after the mammary augmentation.
Bibliography
The list of the main used sources of reference in the preparation of this paper appears by alphabetical order.
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Council on Scientific Affairs, Medical American Association. Silicone gel breast implants. JAMA.1993;270: 2602-2608.
Deapen DM, Brody GS. The ralationship between breast to cancer and augmentation mammaplasty: an epidemiologic study. Plast Reconstr Surg. 1986.77:361-368.
Gabriel, Melton LJ, Woods JE, ET to. Silicone-containing breast implants and connective-tissue disorders: To population-based retrospective cohort study. Arthritis Rheum. 1993;36:S70.Abstract.
LeVier RR, Harrison MC, Cook RR, Lane TH. What is the silicone? Plast Reconstr Surg. 1993;92:163-167.
Mayo Clinic. Silicone breast implants: putting the headlines into perspective. Mayo Clinic Health Letter. July 1992:7.
Peters N, Keystone and, Snow K ET to. Is there to relationship between autoantibodies and silicone-gel implants? Ann Plast Surg.1994;32:1-7. Includes invited discussion by Marc C. Hochberg, Md, MHP.
Schusterman MA, Kroll SS, Reece GP. Incidence of autoimmune disease in patients to after breast recontruction with silicone gel implants versus autogenous tissue; to preliminary report. Ann Plast Surg. 1993;31:1-6.