BACKGROUND Tooth loss impairs the OHRQoL. Dental implants have expanded treatment options of edentulous patients and improved their OHRQoL, however, in the posterior maxillary sextants the possibility to place implants of desired length and diameter could be limited. lSFE and tSFE represent two surgical options to vertically enhance the available bone in the edentulous posterior maxilla. Invasivity, relevant postoperative discomfort, high costs, and long times needed for the finalization of the prosthetic rehabilitation, however, strongly limit the indications of lSFE and support the need for less traumatic procedures with similar clinical effectiveness and reduced morbidity. In 2008, the investigators proposed a user-friendly, safe, predictable and effective minimally-invasive procedure for tSFE, namely the Smart Lift technique.

AIMS/OBJECTIVES The general aim of the present project is to validate the Smart Lift technique as a simplified and minimally-invasive procedure for the implant-supported rehabilitation of patients with edentulous, atrophic maxillary posterior sextants.

METHODS In a multicenter RCT study design, the reconstructive (clinical) and patient-centered outcomes of tSFE performed according to the Smart Lift technique will be compared with those of conventional lSFE.

EXPECTED RESULTS The Smart Lift technique should allow for a significant reduction of treatment time, post-surgery complications and costs and an increase in the satisfaction perceived by the edentulous patient with implant-supported rehabilitation, while maintaining a clinical efficacy as well as a similar or lower morbidity and discomfort when compared to lSFE. In other words, the investigators expect that more favorable risk-benefit and cost-utility ratio, as well as a better performance in terms of pain, comfort, physical, social and psychological effects of oral health, and issues concerning the OHRQoL, will be observed for the Smart Lift technique compared to lSFE.

List of Acronyms (in alphabetical order) OHRQoL: Oral Health - Related Quality of Life lSFE: sinus floor elevation with a lateral approach RCT: randomized controlled trial tSFE: sinus floor elevation with transcrestal approach

Inclusion Criteria:

Patient-specific

• age≥ 21 years;
• good physical status (ASA1 and ASA2 according to Physical Status Classification System) (American Society of Anesthesiologists);
• systemic and local conditions compatible with implant placement and sinus floor elevation procedures;
• indication to a fixed, implant-supported prosthetic rehabilitation with sinus floor elevation as part of the comprehensive oral rehabilitation plan;
• patient willing and fully capable to comply with the study protocol.

Site-specific For a site to be considered as experimental (and thus included for analysis), the following criteria must be fulfilled:

• at least 6 months elapsed from tooth/teeth loss;
• residual bone height (as radiographically assessed) ≥3 mm and ≤6 mm;
• receiving an implant 3.5 ÷ 5 mm wide, ≥ 8 mm long and at least 5 mm longer than the residual bone height.

Exclusion Criteria:

• current heavy smoking (≥ 20 cigarettes/day for ≥ 6 months prior to and at the time of the surgical procedure);
• untreated periodontal disease prior to implant placement;
• history of radiation therapy in the head and neck area;
• history of chemotherapy;
• systemic disease or conditions with a documented effect on bone metabolism and/or osseous healing;
• past (within 6 months prior to enrollment in the study) or current treatment with any medication with a documented effect on bone metabolism and/or osseous healing;
• physical or mental handicap that can interfere with adherence to the study procedures and adequate hygienic compliance;
• documented allergy to dental materials involved in the experimental protocol;
• pregnancy or lactation;
• history of drug or alcohol abuse.

Moreover, participants will be exited from the study immediately upon:

• request to withdraw from further participation;
• development of acute dental, peri-implant or oral conditions requiring treatment;
• development of conditions conflicting with the exclusion criteria listed above;
• failure to comply with study instructions/requirements.

Site-specific

• presence of endodontic lesions at teeth adjacent to the implant site;
• previous bone augmentation/preservation procedures at the designated implant areas;
• diagnosis of maxillary sinusitis at the experimental quadrant;
• need for concomitant lateral/vertical bone reconstructive procedures other than maxillary sinus floor elevation.