A method and apparatus are provided for determining the preload in a
dental implant system. The preload is determined by transmitting a sonic
impulse, which is preferably an ultrasonic impulse, at a predetermined
frequency to the head of the implant screw through a transducer, which
may be incorporated into the head of the screw, the head of a wand which
generates the sonic impulse, or the transducer and pulse-generating
instrumentation may be incorporated into a torque generating instrument
used to tighten the screw. The preload is determined by measuring the
delay between the first and second reflections through the preloaded
screw to determine a preload value and comparing that value with a
pre-established baseline value for the screw, and comparing the
difference with a predetermined table of values to determine the preload
on the screw.