Background
Dental implants have been widely accepted as a major way to replace missing teeth and have been rapidly applied in partially dentate patients. For patients seeking implant therapy, the surgery is anticipated to be minimally invasive and less painful. Thus, methods for implant placement and second stage surgery should be carefully selected, aiming at reducing surgical complexity and patient visits. Also, the implant should be well-functioning, with satisfying esthetic effects and long-term periodontal stability.Incision designs are considered closely correlated to papilla height, which have been investigated by several researchers in recent years. However, the results remain controversial. Some believe that the application of U-shape flap reduces the risk of gingival recession 