Abstract
Internal voids in impression material are troublesome in clinical practice because they influence reproducibility of details and physical property of impression material. However, distribution and area of fine internal voids have been rarely measured quantitatively in many studies concerning them.
Therefore, we attempted to measure internal voids by digital image analyzer which has been used for quantitative analysis in dental studies recently. Measurement accuracy of device, treatment method to clear the margin of internal voids and influence of rotating original image on video input were investigated.
On calibration and video input, enlargement of original image with a zoom up lens was effective in improvement of measurement accuracy. Deviation of the examined value depended on position of CRT monitor was less than 1%. Catalyst of Bite-checker (GC Dental Industrial Corp.), used as a treatment material of internal voids, made the margin of internal voids the most clear compared to four other. It was necesary to adapt the mean of six measurements by rotating the original image 60 degrees each in order to make negligible the variation of directional dependence of video input.
From the above results, by direct input of specimen information into the digital image analyzer, measurement became fast and simple, and reproducibility and objectivity of the examined value were excellent in comparison with other measuring methods.
