Paper: Evaluation of Zirconia Crowns made from Conventional and Digital Impressions (AADR Annual Meeting (March 21-24, 2012))

Friday, March 23, 2012: 8 a.m. - 9:30 a.m.

Presentation Type: Oral Session

D.J. FASBINDER, Dept. of Cariol & Rest. Sci. & Endo, University of Michigan, Ann Arbor, MI, G.F. NEIVA, Cariology, Restorative Sciences and Endodontics, University of Michigan, Ann Arbor, MI, J. DENNISON, Cariology ,Restorative Sciences and Endodontics, University of Michigan, Ann Arbor, MI, and D. HEYS, University of Michigan, Ann Arbor, MI

Objective:

This randomized clinical trial studied the clinical performance of a CAD/CAM-generated veneer zirconia crown (Lava DVS/3M ESPE) compared to a hand-layered veneer zirconia crown (Lava/3M ESPE). The baseline placement of the crowns was used to evaluate the fit and internal adaptation of the crowns.

Method:

Two clinicians placed 100 zirconia crowns with the surface veneer fabricated with two different processes. The first 25 cases of each crown type had two identical crowns made; one from a conventional polyvinylsiloxane impression (PVS) and the other from a digital impression (Lava COS/3M ESPE). The time required to adjust and repolish both crowns for cementation was recorded. A light body PVS impression material was injected in the crown to record the cement space. After removing the crown/PVS, a heavy body PVS material was added over the light body PVS. The PVS impression material die was sectioned faciolingually into three pieces. The sections were measured with a measuring microscope at 20X for margin fit, axial wall adaptation, and occlusal wall adaptation.

Result:

A two-way ANOVA indicated no significant difference in crown fit between the two types of crowns (p>0.05) but there was a significant difference based on impression technique (p<0.05). A T-Test indicated a significant difference in impression technique for each category (p<0.05).

microns

Margin

Axial

Occlusal

PVS crowns

78.62+25.62

93.75+35.89

162.03+47.22

Digital crowns

51.45+18.59

79.06+23.98

119.91+38.18

A two-way ANOVA indicated no significant difference in adjustment time between the two types of crowns or impression techniques (p >0.05).

minutes

Proximal Contacts

Margins

Occlusion

Repolish

Total

PVS crowns

1.70+2.83

0.53+0.62

2.37+2.40

2.03+1.94

6.63+5.04

Digital crowns

1.66+2.06

0.49+0.43

2.17+2.37

1.72+1.63

6.04+4.76

Conclusion:

The crowns made from digital impressions fit significantly better than crowns made from PVS impressions. The time required to adjust the crowns was equivalent This study was supported by a grant from 3M ESPE.

This abstract is based on research that was funded entirely or partially by an outside source: 3M ESPE

Keywords: CAD/CAM, Ceramics, Digital Impressions and Impression materials

Presenting author's disclosure statement: I am serving a term as a member of the Scientific Advisory Board of 3M ESPE.

See more of: Clinical Studies
See more of: Dental Materials 4: Clinical Trials

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microns	Margin	Axial	Occlusal
PVS crowns	78.62+25.62	93.75+35.89	162.03+47.22
Digital crowns	51.45+18.59	79.06+23.98	119.91+38.18

minutes	Proximal Contacts	Margins	Occlusion	Repolish	Total
PVS crowns	1.70+2.83	0.53+0.62	2.37+2.40	2.03+1.94	6.63+5.04
Digital crowns	1.66+2.06	0.49+0.43	2.17+2.37	1.72+1.63	6.04+4.76

644 Evaluation of Zirconia Crowns made from Conventional and Digital Impressions