RCT Comparing KS Versus TS for Ovedenture

Inclusion Criteria: * Any edentulous patient (post-extractive sites must to be healed from at least 3 months), with sufficient bone height and width in the anterior mandible (between canines) to allow the placement of two implants of 3.5 mm diameter of at least 8.5 mm of length. * 18 years or older, and able to sign an informed consent. * Smokers will be included and categorized into: 1) non smokers; 2) moderate smokers (smoking up to 10 cigarettes/day); 3) heavy smokers (smoking more than 11 cigarettes/day). * In case of post-extractive sites, they must have been healing for at least 3 months before being treated in the study. Exclusion Criteria: Exclusion criteria * General contraindications to implant surgery. * Patients irradiated in the head and neck area. * Immunosuppressed or immunocompromised patients. * Patients treated or under treatment with intravenous amino-bisphosphonates. * Patients with untreated periodontitis. * Patients with poor oral hygiene and motivation. * Previous guided bone reconstruction at the intended implant sites. * Uncontrolled diabetes. * Pregnancy or nursing. * Substance abuser. * Psychiatric problems or unrealistic expectations. * Lack of opposite occluding dentition in the area intended for implant placement. * Patients with infection and or inflammation in the area intended for implant placement. * Patients participating in other studies, if the present protocol cannot be properly adhered to. * Patients referred only for implant placement and cannot be followed ant the treating centre. * Patients unable to be followed for 5 years.