In their study “Finite Element Stress Analysis of the Influence of Staggered Versus Straight Placement of Dental Implants” (Int J Oral Maxillofac Implants 2001;16:722-730) Drs. Kivanc Akca and Haldun Iplikcioglu, created a virtual mandible and placed implants of various sizes in various configurations. In each case three implants were placed in a row in the posterior mandible. The most interesting alignment comparisons consisted of straight and offset for 10mm x 3.75mm implants, as well as. straight for 10mm x 4.1mm implants. Both lateral and compressive forces were placed on the implants, and the most stress on the simulated bone was found with a straight alignment of 3.75mm diameter implants. Less stress was found on the offset 3.75mm diameter implants. The least stress was found on the 4.1mm diameter implants.

Compression for 3.75mm Diameter Implants			4.1mm Diameter
Tensile Stress for 3.75mm Diameter Implants			4.1mm Diameter

The model assumes 100% bony contact, consistent density of the bone in contact with the implant, and separates the vertical and lateral forces. None of these significant assumptions occur in the mouth. Even with this in mind this study should be remembered when placing implants in the posterior of the maxilla or mandible, where the bone is softest a little attention to offset location and wider diameters may be the difference between long term success and failure.

Note the red areas of this posterior mandible are the same density as the surrounding soft tissue.