Hello, In general, dermal fillers are not very effective for treating horizontal forehead lines. I believe you are referring to the wrinkles on the forehead that are horizontal or parallel to the ground. These static (fixed or stationary) wrinkles, of various depths, do not typically respond well to fillers, especially as a single modality treatment. The best initial treatment for forehead wrinkles is Botulinum Toxin such as Botox, Dysport or Xeomin. The forehead wrinkles are created by the contraction of the underlying frontalis muscle. The muscle fibers contract vertically (up and down) and this results in the creation of a perpendicular forehead wrinkle. Over time the wrinkle becomes deeper and more noticeable. By partially paralyzing the muscle with Botox, the wrinkles relax and become less visible. If after Botox is used on the forehead and residual wrinkles remain, one can consider the use of a filler to further improve the appearance of the forehead lines. Of the available dermal fillers currently FDA approved, Artefill, (now called Bellafill) in my opinion would be a poorer choice since this filler is injected deeper or beneath the skin. If a dermal filler was used on the forehead to improve horizontal static wrinkles, I would choose a filler such as Restylane Silk or Belotero. These hyaluronic acid fillers are made up of smaller particles and formulated for injection into more superficial (shallow) skin layers. No filler is FDA approved for correction of forehead wrinkles so using any filler in this area would be considered off label use. Restylane Silk has recently been FDA approved for the lips and the vertical (barcode) lines that form around the lips. Belotero is FDA approved for use in the nasolabial folds as well as other moderate-to-severe etched-in lines and wrinkles around the lips and mouth. These two fillers may be a better choice for off label use in persistent forehead wrinkles not completely corrected with Botox. Keep your expectations reasonable. there is no guarantee that the filler will erase the lines you are concerned about.