The present prospective study was conducted at a private practice (Tommaso Grandi, Modena) in Italy between October 2014 and January 2016.

Any patient with partial edentulism in posterior regions of mandible (premolar/molar areas), requiring one multiple tooth implant-supported restoration (2-, 3-, or 4-unit bridge), having a residual bone height of at least 8 mm and a thickness of at least 4 mm measured on computerized tomography (CT) scans, and who was 18 or older and able to sign an informed consent form, was eligible for inclusion in this trial. Preoperative periapical X-rays were used for initial screening, followed by computer tomography scans to precisely quantify the amount of bone. Patients were not admitted in the study if any of the following exclusion criteria was present:

1. general contraindications to implant surgery,
2. residual bone thickness greater than 5 mm,
3. subjected to irradiation in the head and neck area,
4. treated or under treatment with intravenous amino-bisphosphonates,
5. poor oral hygiene and motivation,
6. untreated periodontitis,
7. uncontrolled diabetes,
8. pregnant or lactating,
9. substance abusers,
10. lack of opposite occluding dentition in the area intended for implant placement.

The principles outlined in the Declaration of Helsinki on clinical research involving human subjects were adhered to. All patients received thorough explanations and signed a written informed consent before being enrolled in the trial. Forty-two patients were consecutively recruited and treated in a private dental practice by one operator (Tommaso Grandi, who performed all the surgical and prosthetic interventions).

All patients underwent at least one session of oral hygiene instructions and professionally delivered debridement when required prior to the intervention. Anti-microbial prophylaxis was obtained with 1 g of amoxicillin and clavulanic acid (Augmentin, Roche S.p.A., Milan, Italy) every 12 h from the day before surgery to the sixth postsurgical day. Patients allergic to penicillin were given clarithromycin 500 mg (Klacid, Abbott srl, Roma, Italy) 1 h before the intervention and 250 mg twice a day for one week.