IngentaConnect Factors influencing optical 3D scanning of vinyl polysiloxane imp...

Abstract:

Purpose :

Future growth in dental practice lies in digital imaging enhancing many chairside procedures and functions. This revolution requires the fast, accurate, and 3D digitizing of clinical records. One such clinical record is the chairside impression. This study investigated how surface angle and surface roughness affect the digitizing of vinyl polysiloxane impression materials. Materials and Methods :

Seventeen vinyl polysiloxane impression materials were digitized with a white light optical digitizing system. Each sample was digitized at 3 different angles: 0°, 22.5°, and 45°, and 2 digitizer camera f-stops. The digitized images were rendered on a computer monitor using custom software developed under NIH/NIDCR grant DE12225. All the 3D images were rotated to the 0° position, cropped using Corel Photo-Paint 8 (Corel Corp, Ottawa, Ontario, Canada), then saved in the TIFF file format. The impression material area that was successfully digitized was calculated as a percentage of the total sample area, using Optimas 5.22 image processing software (Media Cybernetics, LP, Silver Spring, MD). The dependent variable was a Performance Value calculated for each material by averaging the percentage of area that digitized over the 3 angles. New samples with smooth and rough surfaces were made using the 7 impression materials with the largest Performance Values. These samples were tested as before, but with the additional angle of 60°. Silky-Rock die stone (Whip Mix Corp, Louisville, KY) was used as a control. Results :

The Performance Values for the 17 impression materials ranged from 0% to 100%. The Performance Values for the 7 best materials were equivalent to the control at f/11 out to a surface angle of 45°; however, only Examix impression material (GC America Inc, Alsip, IL) was equivalent to the control at f/11ˆ16. At the 60° surface angle with f/11ˆ16, the Performance Values were 0% for all the impression materials, whereas that for the control was 90%. The difference in the Performance Values for the smooth and rough surface textures was 7%, which was not significant. Conclusions :

The digitizing performance of vinyl polysiloxane impression materials is highly material and surface angle-dependent and is significantly lower than the die stone control when angles to 60° are included. It is affected to a lesser extent by surface texture.

Keywords: 3D scanning; noncontact scanning; optical scanning; addition silicone; vinyl polysiloxane; dental die stone; surface texture

Document Type: Research article

DOI: 10.1111/j.1532-849X.2001.00078.x

Affiliations: 1: Professor. From University of Minnesota School of Dentistry, Minneapolis, MN. 2: Associate Professor. From University of Minnesota School of Dentistry, Minneapolis, MN. 3: Assistant Professor. From University of Minnesota School of Dentistry, Minneapolis, MN. 4: Sr Research Associate. From University of Minnesota School of Dentistry, Minneapolis, MN. 5: Professor and Chair. From University of Minnesota School of Dentistry, Minneapolis, MN.

Factors influencing optical 3D scanning of vinyl polysiloxane impression materials