[Application of the pin-hole marker measurement of the irregular silicone impression accuracy].

ABSTRACT

PURPOSE: To investigate the feasibility of the pin-hole marker measurement of the irregular silicone dental impression accuracy. METHODS: The metal model simulating abutment preparations had triangle-formed circular needles on the surface. Two silicone impressions were made by the metal model with the corresponding pin-hole markers. The dimensional change of the markers was evaluated by stereomicroscope. The records were output by the software which could simulate the centre of a circle to measure the displacement and dimensional accuracy. RESULTS: The outline of pin-hole marker was clear and shape was stable. Values of center coordinates were repeated well. The percentage of linear dimensional change of two impression samples was 0.023% and 0.042% at 48h respectively. Between two abutment preparations, the percentage of linear dimensional change of Zhermeck silicone impression increased 0.214% (45.1µm) at 1h and decreased 0.019% (4.0µm) at 48h while 3M silicone impression increased 0.087%(18.2µm) at 1h and decreased 0.09% (18.8µm) at 48h. CONCLUSION: The pin-hole marker measurement of the irregular silicone impression accuracy was feasible.