The success as well as the esthetics of dental implants is dependent on many factors and one of these is the quantity and quality of the gingival soft tissue (skin). In short, there are two types of soft tissue (gums) that can be present around implants, keratinized gingiva (similar to the roof of the mouth) and mucosa (similar to the inside of the cheek). With this in mind, there are two main reasons for skin grafting around implants:
1) For Keratinized Tissue
In many situations implants are placed into the jaws of people who have lost both bone and tissue through the years. These implants are surrounded by a moveable tissue that is similar to the inside of your cheek. This tissue is easily injured by normal chewing or by the contact of a denture or partial. It can also be pulled away from the implant during chewing allowing food impaction and bacterial invasion which can cause eventual implant failure.
In these situations, small grafts are taken from the roof of the mouth and placed around the implant. A thicker keratinized tissue will develop giving the patient a more comfortable and healthier situation.
2) For Cosmetic Enhancement
Many times, implants are used to replace single missing anterior (front) teeth. In some situations, gum tissue may recede over time eventually showing the metal edge of the implant, thus giving the patient a very un-esthetic outcome. Skin grafts can be used to replace this lost tissue covering the metal appearance.
Also, in some situations, skin grafts are used to balance or thicken tissue around implants to allow a more natural symmetrical relationship with the surrounding teeth. This is often used along with bone grafts to replace missing or atrophied tissue.