The primary outcome of the study was the vertical variation of peri-implant buccal and palatal bone level from implant placement (T0) to uncovering stage (3 months later - T1)

despite various recommendations, there is insufficient evidence to set a threshold for minimal buccal bone thickness necessary to ensure peri-implant marginal bone stability and optimal aesthetic outcomes.

Therefore, the aim of the present multi-centre prospective study was to investigate the influence of buccal and palatal bone thickness at the time of implant placement on peri-implant bone remodeling during the submerged healing period, with a strict control of possible confounding factors.

Inclusion Criteria:

• age > 18 years;
• no smokers;
• no history of periodontal disease;
• healed bone crest (at least six months after tooth extraction);
• crestal bone height ≥8 mm;
• crestal bone with a minimum bucco-palatal width of 6 mm with no concomitant or previous bone augmentation procedures.

Exclusion Criteria:

• absolute contraindications to implant surgery
• immunological or genetic disorders;
• uncontrolled diabetes (HBA1c > 7.5%);
• present or past treatment with anti resorptive drugs;
• oncologic patients;
• history of head or neck radiotherapy;
• alcohol or drugs abuse;
• final insertion torque > 50 Ncm.

Any patient presenting a single edentulism in the upper premolar area and requiring implant-prosthetic rehabilitation was eligible for this study. Furthermore, patients have to comply with the following inclusion and exclusion criteria.