Some Medical Letter consultants have suggested that our recent article on dermal fillers (Med Lett Drugs Ther 2007; 49:39) should have included stronger warnings about the risk of fillers that are not biodegradable, such as Artefill. The polymethylmethacrylate (PMMA, the same material that makes up Plexiglas) beads in Artefill can over time, even with the best technique, cause foreign-body granulomas and hypertrophic scarring, which may require surgical removal. Granulomas and nodules have been especially frequent when Artefill was injected into the lips. Complications are less likely with hyaluronic acid products such as Hylaform, Juvéderm or Restylane.