Central Incisors Narrow Implants in Alternative to Bone Augmentation With 4.2 mm Implants .

Inclusion Criteria: * Upper central incisor edentulism * bone width between 3.5-4.5 mm * requirement of only one implant supported crown * patient is willing to sign an informed consent Exclusion Criteria: * General contraindications to implant surgery. * Immunosuppressed or immunocompromised patients * Patients irradiated in the head and neck area. * Patients with poor oral hygiene and motivation. * Uncontrolled diabetes. * Pregnancy or lactation. * Addiction to alcohol or drugs. * Untreated periodontal disease. * Treated or under treatment with intravenous amino-biphosphonates. * Poor oral hygiene and motivation. * Psychiatric problems and/or unrealistic expectations. * Acute infection (abscess) or suppuration in the area intended for implant placement. * Patients referred only for implant placement if cannot be followed at the treatment centre. * Patient unable to attend the follow-up controls for 3 years after implant loading. * Patient included in other studies, if this protocol cannot be properly followed. * Immediate post-extractive sites (to be eligible at least 3 months must have passed since extraction).