An in vivo investigation of seating and removal forces associated with recording impressions in dentate patients.

This in vivo study examined forces exerted during the recording of impressions of dentate maxillary arches. This study consisted of 10 subjects; four impression materials in metal stock trays and disposable plastic trays were used. The load rate and the maximum insertion and removal forces were measured with strain gauges mounted on the tray handles. The results indicated considerable variations in forces and load rates related to material, subject, and tray type. Lower forces were measured with the disposable trays. The greatest mean peak removal forces were 36.3 N with a metal tray/elastomer combination and 19.9 N with the same material used in a plastic tray.