······························································································· iii
1. ···················································································· 4
. ············································································· 4
. ················································································ 9
2. ································································· 10
. ······························································································ 13
. ······························································································ 17
impression technique ·················································· 7
Figure 4. Screen shots of 3D reconstructed model from iTero
digital impression ······················································· 8
Figure 5. Example of the definitive cast using digital impression
technique ··································································· 8
definitive casts ··························································12
model ·······································································11
impression and definitive casts fabrication technique ·····11
iii


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6mm
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CAD/CAM
.13 Electronic impression device(EID)

computer aided manufacturing
system(CAM) .14


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iTero system(Cadent Inc., Carlstadt, New
Jersey, USA) .14 iTero system (parallel
confocal) , (triangulation
sampling) CEREC system
.16 14 x 18 mm2
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. (telecentric)

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. milling machine
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1.
.
, 1 , 2
(Warantec, Seoul, Korea) (Figure 1).
shoulder , 6mm, 6
. 1 5mm, 2 6mm .
Fig 1. Modified typodont master model and abutments. (A: Frontal view
of master model, B: Dimensions of abutments)
A B
(LPM), 1 2 (RPM), 2
1 (XA1), 2 1
(XA2) .
Fig 2. Occlusal reference points of master model. Same points were used
to measure on definitive casts.
6
Company, Skokie, Illinois, USA)
. (V.P.S. Tray Adhesive, Kerr, California,
USA) 15
(Aquasil Ultra XLV, Dentsply Caulk, Milford, Delaware, USA)
. (Fuji-Rock RP, GC International,
Scottsdale, Arizona, USA) 100g 20ml
. 24
(Figure 3). 10
10 .
Fig 3. Example of the definitive cast using conventional impression
technique.
USA) .
iTero , , , , 5
2
. 3

. iTero center CAD
(Figure 4). STL file
iTero computer numerical control milling machine(VF-2TR,
8
10 .
Fig 4. Screen shots of 3D reconstructed model from iTero digital
impression. The data files undergo a modeling process and finishing
margin determination.
Fig 5. Example of the definitive cast using digital impression technique.
B
9
(CD-10CPX 500-180-20, Mitutoyo, Tokyo, Japan)
.
0.01.
10
. 3 .
.
.
(SAS 9.2 ver, SAS Institute Inc, Cary,
North Carolina, USA) 95% t-
.
10
(Table 1).
(Table 2).
11
Table 1. Means and SDs of measured distance() of master model
PP MM LPM RPM XA1 XA2
Mean 29.62 49.84 30.57 30.83 48.89 49.34
(SD) (0.01) (0.00) (0.01) (0.01) (0.01) (0.01)
ME% 0.03 0 0.03 0.03 0.02 0.02
ME means coefficients of variability (percent errors)
Table 2. Mean distance(SDs) of definitive casts according to impression
and definitive casts fabrication technique (n=10)
Distance () PP MM LPM RPM XA1 XA2
Conventional 29.63
Fig 6. Differences() in dimensions between master model and definitive
casts.

.

.

.

vinyl polysiloxane
.12, 17, 19, 20
,4


.21 Kang 11 Johnson 19
.

.17
.
14
0 ~ 0.04
,
. Ender Mehi22


. Ender Cerec
AC Bluecam Lava COS system
.
stereolithography .
iTero system
100,000
.

, 13.5 focal depth . iTero system
15 16

.
.
milling machine 2
15
.16

.
,23
24 25
. Tjan 26 90
.
, 100 ~ 150
.27
. Vigolo 28
34
. Kwon 29

81
.

.
.


16
.

.
17
.
.
1.
.
2. iTero system
.
3. iTero system
.
18

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21
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22
Abstract
and conventional impression technique
(Directed by professor Chong Hyun Han, DDS, MSD, PhD)
Purpose : The purpose of this study was to evaluate and compare the
dimensional accuracy of definitive casts that are fabricated from digital
impression system and conventional impression technique.
Materials and methods : Impressions were made from a modified dentoform
master model containing standard abutments. Dimensional changes()
between the master model and definitive casts were assessed. Ten
23
impressions were made with either vinyl polysiloxane impression material or
digital impression system. The conventional impression was cast in
improved dental stone. Working casts for digital impression system were
fabricated by milling polyurethane block. Measurements of the master model
and definitive casts, including anteroposterior and cross-arch dimensions,
were made with digital calipers. The data were analyzed by independent t-
test(p<.05).
Results : The definitive casts obtained with conventional impression
technique had significantly larger dimensions as compared to those of the
master model. Differences between the digital impression working model and
the master model were not significant.
Conclusions : The digital impression system demonstrated acceptable
accuracy for clinical use , since the results for digital impression system
were comparable to the results for vinyl polysiloxane materials, and the
differences as compared to the master model were small.
Key words : digital impression system, definitive cast , accuracy of
impression technique