Dynamic wrinkles occur during a facial expression (such as joy, sadness, anger, etc.) when specific muscles of the face contract. They are called dynamic wrinkles or expression lines because immediately after the expression, the skin returns to its original position, causing the wrinkles to disappear. However, the muscle contractions that cause them weaken the tissue connections, and over time, these temporary expression lines inevitably turn into permanent or static wrinkles.
Static wrinkles are deep folds that carve into the skin, causing it to look aged. They are caused by chronological aging, which leads to the relaxation of tissues due to the reduction in collagen, elastin, and hyaluronic acid production. Static wrinkles are visible even when the face is calm and expressionless, and they deepen and become more entrenched in the skin over time.