The purpose of this prospective clinical study was to compare in delayed and immediately placed implants, the marginal vertical bone loss at 4 sides of the implant (buccal, palatal, mesial and distal), as well as the buccal and palatal bone thickness reduction at 3 months after loading.

Twenty-four patients were consecutively selected and enrolled in this study based on the aforementioned exclusion and inclusion criteria. Clinical examination was done by a different clinician than the operator, and according to the treatment indication, patients were allocated to the delayed implant placement group (Control), or the immediate implant placement group (Test). Thus, 15 implants were placed in healed extraction sites and immediately temporized (Control group), and 15 implants were placed in immediate extraction sites with immediate temporization (Test group).

Provisional acrylic crowns were prepared. All patients were placed on a prophylactic antibiotic regimen, starting one day prior to surgery as they were asked to take amoxicillin 500 mg; three times a day for 10 days or clindamycin 300 mg twice daily for 10 days for penicillin-allergic patients.

For the test group, tooth extractions were carried out atraumatically using periotomes. In both groups, the implant site preparation was completed in compliance with the general surgical principles and protocols defined by the manufacturer and screw-shaped implants (UFII, DIO™) were inserted at no less than 35 Ncm.

Temporary abutments were connected to the implants and torqued at 20 Ncm, and then temporary crowns were cemented on top of the abutments after checking and reducing occlusion to non-existent in both centric and lateral excursions.

Inclusion Criteria:

• Adults over 18 years old, compliant (willing to show up to all their follow-up visits), and able to read, understand and sign an informed consent. All patients were to have good oral hygiene levels (full mouth plaque scores (FMPS) <15-20%, and full mouth bleeding index (FMBI) <15-20%), requiring implant insertion in a maxillary premolar site either immediately or in a healed "pristine bone".

Exclusion Criteria:

• Presence of major contraindications to implant surgery, patients that had received head and neck radiation for cancer treatment, immunosuppressed or immunocompromised patients, uncontrolled diabetes, pregnant or breast-feeding woman, untreated periodontitis and/or poor oral hygiene and motivation, presence of buccal dehiscence, and finally previous bone grafting or ridge preservation in the studied area.

Patient characteristics. Outcome measures

6 months after publication for 10 years

The complete dataset can be available for researchers working on a meta-analysis

The radiographic measurements were done by a different clinician than the surgeon