I have many patients that are concerned about silicone, but they are actually very safe devices. I personally waited 7 years before getting implants just so silicone was available again.
The "form stable" or "gummy bear" implants (released on 2012 here in the US but used in Europe and Canada for over 20 years) have the lowest rates of rippling. However, those have a very different look than you have now.
There is a newer (again only new to the US) implant called the Inspira that has a thicker gel and is overfilled to minimize rippling for even post mastectomy patients.
If if you want the lowest chance of rippling, it may indeed be necessary to consider a sling of graft material to cover the bottom part of your breast, and if you downsize significantly, you may even need a lift to make sure the implants sit in the right place on your chest. But these are all issues best addressed during a formal consult with a board certified plastic surgeon.