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ePaper created 2017-05-12, 09:42:21 | version 1.38.0
| case report Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 5: Initial dental situation after a first professional dental hygiene. Fig. 6: Upper arch. Fig. 7: Lower jaw. Fig. 8: Initial orthopantomography. which therefore do not have the financial ability and/ or cultural demand to replace missing teeth. In such cases, teeth have mostly been lost due to careless- ness (caries and periodontitis),2,3 iatrogenic damage (dental treatments not performed according the state-of-the-art),4 systemic diseases such as diabe- tes and immunosuppression,5 or incorrect lifestyle (eating habits, drug use, smoking)6. No prosthesis is able to completely restore the chewing ability,7 but anyway, life quality of patients with prosthesis is much better than in those cases who have no prosthesis8-10. In the maxilla, a high percentage of patients accept a traditional removable prosthesis, while in the lower arch this solution is extremely uncomfortable and not functional. There- fore, it is widely believed in the scientific community that the minimal functional solution in the lower jaw is the inclusion of two implants to stabilise the removable prosthesis.11–16 The restoration of edentulism with a fixed im- plant-supported prosthesis seems to be the best solution. But, especially in the upper arch, this solu- tion is hardly feasible for insufficiency of the remain- ing bone, for weak support of soft tissues (lips and cheeks) and, consequently, for unsatisfying aesthet- ics and phonetics. These factors often require pre-implant bone reconstruction with a significant increase of time, costs and morbidity (Figs. 1–4). The easiest and handiest way therefore seem to be overdentures stabilised by a reduced number of implants. In the upper jaw we can sensibly limit the extent of the palate, improve the general comfort of the patient and his gustatory perception and at the same time decrease inflammatory and/or infectious mucositis.17, 18 We have already reported that in the edentulous mandible the minimally accepted therapy is an overdenture stabilised by two implants.11, 14 The best results in terms of implant survival and prostheses outcome in the upper jaw is obtained with at least four implants bonded by a bar.19, 20 On the other hand, in the mandible there have not been reported differ- ences regarding implant survival and patient com- fort by inserting two or four implants bonded by a bar or using non-bonded implants (ball-attachment or locator).21 Even scientific publications attested that still today the validity of a removable denture stabilised by implants22 placed ten years ago were given a further opportunity to resolve total edentu- lism with a fixed prosthesis supported by a reduced number of implants. Since the first publication of Maló et al.,23 the sys- tematic "All-on-4" has gained approval by operators and patients. The concept "All-on-4" allows to have a fixed denture in acrylic resin supported by only four implants of which the two distal inclined as much as possible to displace distal the prosthetic emergency; the prosthesis is screwed to the implants immedi- ately after their placement (within 48 hours). In sub- sequent years, this method has been confirmed to be safe and reliable.24-26 By contrast, in severe atrophy 14 implants 2 2017