| Summary: | 碩士 === 國立臺灣大學 === 臨床牙醫學研究所 === 106 === Research goal
The purpose of this study was to investigate the thickness of the spraying powder
applied on the teeth when using the intraoral scanner, and the relationship between the spraying time、thickness of the powder and the covering area of the powder.
Material and Methods
Forty gypsum blocks (size: 6cm x 2cm x 2cm) were used as the testing samples. A
reference scan was done with lab scanner (3shape D900 lab scanner) for each testing block before the standard powder spraying procedure. The testing blocks were divided into four groups according to the spraying time, and each group have 10 testing blocks (n=10). Scanning powder was applied with spraying machine(3M™ High-Resolution Sprayer ) to each testing blocks under different spraying time(1 sec、3 sec、5 sec、7 sec).
A test scan was performed for each testing block after the powder spraying. Reference scan and test scan of each testing block were imported into the software (Geomagic® Control) and superimposed through best fit algorythm, for analyzing the thickness and the area of the powder. Statistical analyses were performed with descriptive statistics and Pearson correlation.
Result
The mean thickness of the spraying powder for each spraying time group :
8.9 μm (SD ± 1.5μm) for 1 sec、10.0 μm (SD ± 2.2μm) for 3 sec、13.9 μm(SD ± 3.5μm) for 5 sec and 13.3 μm (SD±3.1μm) for 7 sec. The mean area proportion of the spraying powder for each spraying time group : 2.94% (SD ± 1.32%) for 1 sec 、
5.07% (SD ± 2.76%) for 3 sec、8.37% (SD ± 3.35%) for 5 sec and 8.65% (SD ±
3.01%) for 7 sec.
Conclusion
Based on the finding of this investigation, both powder thickness and powder
spraying area increased with longer powder spraying time. The thickness of the powder ranged from 8.9 μm to 13.9 μm under reasonable spraying time. The thickness of the powder may influence the scanning accuracy, but it is clinical acceptable.
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