The main target of the study is to compare ultra-narrow diameter implants (2.75 mm) without bone regeneration versus standard diameter implants (4.3 mm) in combination with bone regeneration. To do so, patients with missing upper central incisors, canines, first or second premolars with alveolar ridges of 6 - 8 mm of thickness will be restored with dental implants. Cone beam computed tomographic examination and clinical values will be registered before and after the surgical procedure at 6 and 12 months.

Inclusion Criteria:

• One missing teeth in position: upper central incisor, canine or premolar
• alveolar ridge thickness of 6 - 8 mm
• alveolar ridge height of ≥ 10 mm

Exclusion Criteria:

• Missing data
• ASA ≥ III