Anatomical bases for the insertion of zygomatic implants.

PURPOSE The purpose of this study was to obtain anatomical information for installing four zygomatic implants, by measurements of maxillae and zygomata. MATERIALS AND METHODS Linear and angular measurements were obtained from the maxillae and zygomata of 40 dry skulls. RESULTS Based on mean and standard deviation values, the installation angle of the additional implant in the four zygoma technique was between 25 degrees and 47 degrees , and that of the conventional zygomatic implant was between 39 degrees and 62 degrees . The distance between the alveolar crest in the canine region and the lateral margin of the orbital socket was 53.42 mm, and between the alveolar crest in the premolar region and the area closest to the lateral margin of the orbital socket was 42.47 mm. CONCLUSIONS When the angle of installation of the additional implant is less than 25 degrees and that of the conventional zygomatic implant is less than 39 degrees , perforation of the maxilla, zygoma, or the infratemporal fossa must be avoided. When the angle of installation of an additional implant is greater than 47 degrees and that of the conventional zygomatic implant is greater than 62 degrees , perforation of the orbital floor must be avoided. The length of an additional implant was greater than the length of a conventional zygomatic implant, and should be measured prior to drilling, because the greatest value found for this distance was 61.94 mm, while the maximum length of the zygomatic implants currently available on the market is 52.5 mm.