Consensus statements and clinical recommendations on treatment indications, surgical procedures, prosthetic protocols and complications following All-On-4 standard treatment. 9th Mozo-Grau Ticare Conference in Quintanilla, Spain

OBJECTIVES The present consensus report critically evaluates the scientific evidence based on a comprehensive systematic review of the All-On-4 treatment concept, focusing primarily on the treatment indications, surgical procedures and prosthetic protocols, and secondarily on the mechanical and biological complications involved. MATERIAL AND METHODS A systematic review was made in advance of the meeting. Consensus statements, treatment guidelines and recommendations for future research were based on within-group as well as plenary debates and discussions of the systematic review. RESULTS The main indication of All-On-4 standard care is an atrophic maxilla or mandible, with or without remnant hopeless tooth. in ASA I or II patients. This surgical-prosthetic protocol seems efficient, safe and effective in the case of Cawood & Howell class IV, V and VI. It is necessary for the implant to have had an insertion torque of over 35 Ncm for immediate loading. The provisional prosthesis should provide rigidity, being non-flexible in order to avoid micro-movements, and should be strong enough to not fracture. Balanced occlusion without interferences is required, ensuring very gentle dynamic movements. The design of the definitive prosthesis must be cleanable and biomechanically adjusted to the implant position and individual characteristics of each patient. A non-concave acrylic base resting over soft tissue is recommended, facilitating hygiene. Regarding occlusion, a group guide should be made, taking into account whether the antagonist is not a removable complete denture. In that case, bi-balanced occlusion should be assessed. Prosthetic complications occur as a result of fractures of the provisional acrylic prostheses. These problems in turn can be resolved by repair through relining or fixing. The most frequent biological complication is the loss of at least one implant, while the second most frequent complication is the development of peri-implantitis and mucositis. CONCLUSIONS In the treatment of atrophy for full-arch implant supported restorations it is considered that four implants suffice for immediate loading and the final prosthesis, even when there is available bone between the mental foramina or maxillary sinuses. The weakness of the quality of the available evidence indicates that further studies are needed, involving an appropriate design and with adequate follow-up in All-On-4 standard care to confirm the present results mainly in relation to survival rates and complications. Key words:Atrophic jaw, All-on-4, immediate implant loading, edentulous mandible, edentulous maxilla, tilted implant, implant failure, dental implants.