This study aims to assess the treatment outcomes (clinical, functional and subjective) of full arch rehabilitations supported by implants with or without an immediate loading protocol. In this randomized clinical trial 20 fully edentulous patients were treated with full arch rehabilitations on dental implants. In half of the sample, the implants were loaded immediately by means of abutments after emplacement of the implant; but in the counterparts these abutments were connected to implants two months after the surgery (conventional protocol), and until that time the dentures were retained by healing abutments. Treatment outcomes were assessed at 2, 6 and 12 months after surgery. Clinical outcomes were quantified on the basis of implant failure rate, marginal bone loss and the peri-implant gingival index. Functional outcomes were calculated according to masticatory performance, estimated by the mixed fraction of a two-coloured chewing gum after 5, 10 and 15 chewing strokes, by the occlusal force recorded by pressure-sensitive sheets and by the bioelectrical muscular activity. The subjective outcomes of the treatment were assessed using both the oral satisfaction scale (visual analogue scale) and the Spanish version of the Oral Health Impact Profile (OHIP-20).

Inclusion Criteria:

• completely edentulous individuals who had lacked teeth for more than 10 years, routine users of conventional complete prostheses.
• sufficient amount of remaining bone to receive the implants in the region of the mandibular canines (minimum height=15 mm/minimum ridge width= 5mm)
• no evidence of systemic or psychic pathology that might contraindicate the implant treatment.

Exclusion Criteria:

• Those in which oral surgery or cognitive evaluations are contraindicated