Aim: to evaluate and compare radiographic marginal bone loss (MBL) and soft tissue parameters around submerged/two-stage and nonsubmerged/one-stage single implants with same tapered body design and surface, same thread design and distance, and same collar surface (laser-microgrooved), after 3 years of loading.

Materials and methods: 20 submerged/two-stage implants and 20 nonsubmerged/one stage implants were placed randomly with a split mouth design, in 20 partially edentulous patients. Radiographic and clinical examinations were carried out at the implant placement (Baseline, BSL), at the delivery of prosthetic restorations (T0), and at each year of the follow-up period (T1, T2, T3). Plaque index (PI), probing depth (PD), bleeding on probing (BOP), and gingival recession (REC) were recorded. Radiographic marginal bone levels (MBL) were assessed at the mesial (MI) and distal (DI) aspect of implant sites. In addition, the influence of keratinized tissue thickness (KTT) on MBL was investigated.

Inclusion Criteria:

Inclusion criteria were: age ≥ 18 years, good general health, without contraindications to implant surgery, presence of at least two non-adjacent edentulous sites requiring implant therapy. Each implant site had to be located in the left or right hemi-posterior mandible or in the left or right hemi- posterior maxilla.

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Exclusion Criteria:

• Exclusion criteria were: implants placed into regenerated bone, lack of a periodontal chart and periapical radiograph at the beginning and at the end of follow-up period, alcohol and drug abuse, pregnancy, or uncontrolled metabolic disorders, tobacco smoking (> 10 cigarettes/day), full mouth plaque score (FMPS), and full mouth bleeding score /FMBS) ≥25%, periodontally compromised patients (with attachment loss of 3 mm and/or radiographic bone loss of 30% of root length in 30% of sites), teeth adjacent to the implant area (mesial and distal) affected by untreated periodontal and/or endodontic infections.