Hierarchy of restorative space required for different types of dental implant prostheses

Management of the full and partially edentulous arch requires an understanding regarding the amount of vertical and horizontal restorative space that is needed for different types of dental implant prostheses. Failure to design a prosthetic construct without considering space issues can result in a rehabilitation with diminished stability, poor esthetics, and inadequate contours. Therefore, available restorative volume must be computed before initiating therapy to ensure proper prosthesis design.The authors searched the dental literature for articles that addressed space requirements for different types of dental implant prostheses and found a few on this subject.The dental literature indicates there is a 3-dimensional hierarchy of restorative space necessary for different types of implant constructs. The minimum amount of vertical space required for implant prostheses is as follows: fixed screw-retained (implant level): 4 through 5 millimeters; fixed screw-retained (abutment level): 7.5 mm; fixed cement-retained: 7 through 8 mm; unsplinted overdenture: 7mm; bar overdenture: 11 mm; and fixed screw-retained hybrid: 15mm. These dimensions represent the minimal amount of vertical rehabilitative space that can accommodate the above implant prostheses. With respect to horizontal space, computations are needed to account for the discrepancy between an implant and tooth position.Restorative spaces for each type of prostheses are restoration specific and should be considered during treatment planning to facilitate proper case selection and enhance patient satisfaction.