1203 3D-Precision of Dies Made with Different Impression Materials and Techniques

Saturday, March 24, 2012: 8 a.m. - 9:30 a.m.
Presentation Type: Oral Session
S. RUPF, H. RUDOLPH, M. GRAF, C. EDELMANN, and R.G. LUTHARDT, Ulm University, Ulm, Germany

Objectives: The precision of a dental impression is an important and determining factor for the fit of dental restorations. A three-dimensional, non-destructive, computer-aided analysis has been established for the assessment of impression precision applying non-contact digitizing. Aim of this study was the examination of a new range of impression materials.

Methods: Duplicate dies (n=10) of a real model were made with five two-phase impression materials (Flexitime Putty/Flexitime Medium/Light Flow, Flexitime fast&scan Putty/Flexitime fast&scan Medium/Light Flow, Heraeus Kulzer; Honigum Heavy/Light, DMG; Germany), scanned by two different digitizers (Model Scan=MSC); (ODKM97, Fraunhofer IOF, Germany; D700, 3Shape, Denmark) and compared to the corresponding virtual CAD-model. For two materials, the impression itself was digitized (impression scan=ISC) with D700. The differences to the CAD-model were calculated (geomagic, Geomagic Inc., USA) and statistically analyzed with one-way ANOVA (SPSS 19.0, IBM, USA).

Results:

Material

Impression technique

Digitizing

Mean pos. [m]

SD

Mean neg. [m]

SD

Honigum

two-stage

MSC-ODKM97

11,1*

2,4*

-11,5*

1,4*

one-stage

MSC-ODKM97

10,6*

1,3*

-10,2*

1,1*

Flexitime light

one-stage

MSC-ODKM97

10,3

1,7

-8,9

0,6

one-stage

MSC-D700

16,2

1,5

-8,2

0,7

Flexitime medium

one-stage

MSC-ODKM97

14,5

3,3

-9,0

1,2

one-stage

MSC-D700

16,1

1,3

-8,3

0,5

Flexitime fast&scan light

one-stage

MSC-ODKM97

10,3

1,7

-8,7

0,6

one-stage

MSC-D700

14,3

1,1

-7,7

0,4

one-stage

ISC-D700

6,4

1,1

-5,7

0,3

Flexitime fast&scan medium

one-stage

MSC-ODKM97

9,2

2,1

-8,5

0,5

one-stage

MSC-D700

14,5

0,8

-7,7

0,5

one-stage

ISC-D700

5,8

0,4

-5,6

0,4

*Data based on a former evaluation

Conclusion: All materials showed a high, clinically suitable precision with no significant differences. MSC with ODKM97 resulted in statistically significant lower deviations (material dependent p=0.009 to p=0.014) compared to D700. The ISC showed excellent values and significantly higher precision than the MSC as long as the ratio of width and height (1:1.5) was strictly kept. Further studies concerning tooth geometry are needed.

This abstract is based on research that was funded entirely or partially by an outside source: Heraeus Kulzer, Germany DMG, Germany

Keywords: Assessment, Dental materials, Digital image analysis, Impression materials and Polymers