Dear Canadian, As far as I know, there is no Formaldehyde in any of the silicone or saline implants. Many years ago, in the evolution of breasts augmentation, Formaldehyde sponge was one of the many materials used. Obviously, it is not in use anymore. As far as 'gummy bear' implants I would like you to reconsider it for saline implants for the following reasons : 1. Saline implants cost much less. 2. Gummy bear have unnatural hardness to them . 3. Gummy bear implants have to be inserted through long incision in the IMF (infra mammary fold ) which is scar unfriendly , where as saline implants can be inserted through small incision along the sub areola line which is scar friendly. 4. The sub areola incision allow the surgeon to create very nice cleavage and precise new IMF under direct vision and digital feel, where as the fold incision is too far from the cleavage area and too close to the new fold for easy dissection. 5. Saline implants allow for easy correction of size asymmetry unlike gummy bear. 6. Gummy bear require small pocket to maintaine their position which puts them at addition hardening risk due to capsule contracture. This is much less likely with saline implants since the pocket made is large. In regard to your plan to combine breasts augmentation with tummy tuck, I would not recommend it. In my 28 years of plastic surgery practice, I have noticed that patients have a tendency to over estimate their ability to recover from painful operations which tummy tuck and breasts augmentation are. Consequently they stay in bed without ambulation and do not drink due to the heavy dose of pain medications. That can cause severe complication like blood clots, pneumonia etc. It is safer to do the surgeries separetely. Always, consult with experienced board certified plastic surgeons who operate in accredited surgery center for your safety. Check their before and after picture in the photo gallery to make sure that they are numerous, consistent and attractive. Best of luck, Dr Widder