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implants2_2010 _ Introduction Zygomatic implants, first introduced by Brånemark in 1988, are especially suitable for pa- tients with advanced atrophy of the maxilla and who refuse or have suffered a complication after bone grafting procedures. The few studies with large samples and adequate follow-ups1-6 , show excellent results. Survival and success rates, as well as, the incidence of complications are de- tailed below based on a Medline review on zygo- matic implant papers. Traditionally, these implants had a palatal emergence, crossed the maxillary sinus and were anchored in the zygomatic bone. Nowadays, the palatal emergence can be avoided by using the “extramaxillary” implants technique, where the zygomatic implant goes through the lateral wall of the maxillary sinus. The high survival rates (higher than 90 %) and the low incidence of com- plications reported in the reviewed papers, make zygomatic implants a good treatment option for therehabilitationofseverelyresorbedmaxillas.In this paper, the authors will address the anatomy of the region, the indications of these implants, the several available surgical techniques, the sur- vival rates and complications. _The zygomatic implant The classical zygomatic fixture design (Bråne- mark Osseointegration Centre and Exopro, Gothenburg, Sweden) was a self-tapping implant in c.p. (commercially pure) titanium with a well- defined machined surface. It was available in dif- ferent lengths ranging from 30 to 52.5 mm, and was slightly tapered (coronal diameter of 4.5 mm and apical diameter of 4.0 mm). This diameter variation was due to the necessity of increasing the anchorage at the alveolar process while re- ducingtheriskofcomplications(orbitalbleeding, infraorbitary nerve affectation, etc.) in the apical region. The coronal portion of the implant pre- sented a tilted connection of 45° to facilitate the prosthetic rehabilitation.1 At present, this implant has a rough surface andthecoronalportionoftheimplantsmaypres- ent different angles ranging from 25° to 55°. Boyes-Varley et al. 7 proposed a 55° angle in order to avoid the palatal emergence of the prosthetic connection, which is one of the most discussed inconveniences of these fixtures. _Anatomical basis for the zygomatic implant The zygomatic bone could be compared to a pyramid, offering a solid anatomic structure for implantanchorage.8 Ahistologicalanalysisofthis area revealed the presence of a regular and dense bonewithveryhighosseousdensity(upto98 %).9 Due to these features, the zygomatic bone has al- ready been used to place miniplates as a part of the orthodontic treatment. According to an anatomical study, the mean length of useful bone in this region is 14 mm.10 _Indications of the technique AccordingtoMalevezetal.6 andAparicioetal.11 the zygomatic implants are a valid alternative to bonegraftinginpatientswithadvancedmaxillary atrophy. This technique would be suitable when the following conditions are present: Rehabilitation of atrophic maxillas using zygomatic implants A literature review Authors_Joan Pi-Urgell1 , Javier Mir-Mari2 , Rui Figueiredo & Cosme Gay-Escoda3 , Spain