The influence of occlusal design on simulated masticatory forces transferred to implant-retained prostheses and supporting bone. 
The influence of occlusal surface design on the longitudinal success of implant treatment is believed to be significant, but it is not well understood.  It has been suggested that limiting lateral forces by reducing cuspal inclination is beneficial in the maintenance and preservation of osseointegration.  This study used a method to apply quantified vertical forces to a food substance and record the forces and strain transmitted through cusped 33-degree and cuspless 0-degree occlusal design specimens to a simulated implant-retained prosthesis and the supporting bone.  A series of five masticatory cycles were applied to each of the specimens with a universal testing machine.  The data were analyzed to compare (1) forces required to cause initial breakage of the food, (2) maximum breakage forces applied before cycle termination, and (3) maximum strain registered by strain gauges at the bone level.  Initial breakage forces for the cuspless specimen were 50% less than for the cusped specimen (p = 0.006).  No significant differences were found between maximum breakage forces and maximum strain (p values 0.744 and 0.315, respectively).  The results of this pilot study indicated that the occlusal configuration and cusp angulation of implant-retained prostheses play a significant role in force transmission and the stress-strain relationship in bone.