Screw vs. Cement Retained?

Dr. M asks:

I am presently evaluating the design for both upper and lower bar-retained overdentures. The upper will have eight dental implants and the lower will have six dental implants. The position of the dental implants will follow recommended positions as outlined by Misch. My question centers around rather to design a screw-retained or cement-retained bar with attachments.

I am aware that the cement-retained bar will require abutments height of a minimum of five millimeters of height for retention. This simpler design and potential for upfront ease of placement and construction are appealing. Any thoughts as to the comparison of the long-term in comparison to the screw- retained bar vs. the cemented bar? What other factors are important in choosing between one of these techniques? As of present, the type of attachments will probably be a combination of Hader and Locators. Thanks.