A new method to quantify wear using implant supported restorations.

OBJECTIVES: To design a novel technique to assess the wear of prosthodontic veneering materials. Further to determine whether accurate transfer between the oral cavity and the measuring device is achievable and assess the reproducibility of the coordinates generated by the measuring system. METHODS: The system is based on the repositioning capacity of an octagonal connector of the ITI implant system. The same type of connector was screwed onto the clinical implants that supported the experimental restorations and secured to the x-y table of the measuring device. The measuring setup also comprised a z-axis LVDT displacement gauge that allowed the entire surface of the restorations to be profiled and digitized. The system was under the control of a PC equipped with custom-made software that set the position of the stepping motors, lifted and lowered the z-axis probe, and registered and wrote the x-, y- and z-axis coordinates. Final numerical adjustments and analyses were performed using a commercial array-oriented software package. Validation procedures were performed using a specially designed calibration surface. RESULTS: On repeated profile tracings, the measurement error was less than 2 microns. When the calibration surface was removed between measurements as during clinical trials, the measurement error increased to ca. 5 microns. SIGNIFICANCE: The measurement error of the testing procedure including transfer to and from the mouth is +/- 5 microns.