One of the most popular procedures in my office is lip augmentation. I also enjoy the procedure as I am able to creatively sculpt a more full, youthful, attractive and naturally appearing lip. If wider means thicker and more full, then yes, dermal fillers can do this. If you are referring to making your mouth wider, then no, injections cannot achieve this. In terms of longevity, the most popular fillers for lips last about 6-7 months. The lips have a great deal of muscle activity and the hyaluronic acid products get degraded quicker in the lips due to the movement and repetitive activity of the lips. I stay away from permanent fillers and implants in the lips. You will get other opinions but the risks of palpable irregularities, unnatural feel, and unsightly appearance outweighs the upsides for the argument for permanent fillers.