Yes, the type of pillowcase you use can affect the formation of wrinkles. Rough pillowcase materials, like standard cotton, can tug at your skin and create friction as you move in your sleep. This friction can cause the skin to fold and crease, potentially leading to "sleep lines." Over time, these sleep lines can turn into permanent wrinkles, especially if you consistently sleep on the same side of your face. Using silk pillowcases can help mitigate this issue, as silk causes less friction and thus is gentler on the skin, reducing the likelihood of forming wrinkles.