Various silicone scar sheets brands are available. There are some distinct differences in the type of silicones, fabrics, thickness, and adhesiveness among these brands. So which are the best buy? In my opinion the best silicone scar sheets are ScarAway and Oleeva. This because these are the only two brands that use the patented Silon technology. (ScarAway is the former Neosporin Scar Solution)
In short, Silon is a blend of Teflon and a certain type of silicones “which has unusual physical and chemical properties – particularly when formed into thin membranes. Research suggests that Silon acts to hydrate scar tissue, which in turn works to soften scar tissue, reducing its development and causing it to fade away faster.” Wikipedia
But there are more reasons why these two brands offer the best silicone sheets:
Apart from silicones another material is commonly used to create a layer on the outside of the sheets. It is very important that this fabric is breathable. Oxygen should be allowed to transfer because if it doesn’t it can cause skin maceration. Maceration of the skin occurs when it is consistently wet. The skin softens, turns white, and can easily get infected with bacteria or fungi. Source: About.com: Dermatology. A visitor of one of my Squidoo lenses described this wrinkled white skin effect during the use of Dr. Blaine’s Scar Care sheets.
Those who have used silicone sheets know that keeping them attached can be somewhat of a burden. Especially on some (moving) parts of the body such as the face or neck. It should however be noted that the stickier the better does not apply here. If silicone sheets are too sticky they could create too much tension on the freshly formed, still delicate scar tissue which is not desired because it might worsen the scar. The ideal sheet would be sticky enough to help you position it on the scar, and use a medical tape (i.e. cotton or silk) to secure further if necessary.
Thin sheets versus thick pads
Thinner sheets with a compact layer of silicone are more comfortable and more “durable” which means they do not break down and you get more use out of them. The thicker “gel” type pads get dirt, etc embedded in them which is not sanitary when sealing to your skin for hours each day. The thinner sheets can be washed.
The only silicone scar sheets that have the breathable fabric and the thin, washable, medical grade, Silon technology silicones are the ScarAway and Oleeva sheets. Both doctor-level products are manufactured by BioMed Sciences inc. Oleeva Scar Shapes are pre-cut pieces of Oleeva Fabric for targeted scar management following surgery.
It is theorized that hydrating properties play a major role in the mechanism of silicone sheeting. After serious skin injury trans-epidermal water loss is increased.  This water loss is more significant in hypertrophic and keloid scars and may be responsible for increased collagen production (abnormal scar tissue). The semi-occlusive nature of silicone scar sheeting improves scars by providing adequate but not excessive hydration. Dressings that are too permeable to water may be ineffective on scars because they fail to block water loss and related skin healing processes, whereas dressings that are too occlusive may cause skin maceration.
Note: also Scar Fx and Biodermis Epi-derm silicone sheets are medical grade products. This means they have a higher percentage, better quality silicones than some of the brands available in the drugstore.
 Suetake T, Sasai S, Zhen YX, Ohi T, Tagami H (1996) Functional analyses of the stratum corneum in scars: Sequential studies after injury and comparison among keloids, hypertrophic scars, and atrophic scars. Arch Dermatol 132:1453–1458