712 Microleakage Evaluation of All-Ceramic Crowns Bonded Above/Below the CEJ

Friday, March 23, 2012: 10:45 a.m. - 12:15 p.m.
Presentation Type: Oral Session
M. TSAO, S. JOHN, E. DOHERTY, M. FINKELMAN, M. HARSONO, and G. KUGEL, Tufts University, Boston, MA

Objectives: To measure marginal microleakage of bonded IPS e.max lithium disilicate crowns of teeth with marginal preparations above and below the cementoenamel junction (CEJ) between 3 classes of self-adhesive resin luting agents: 1-RelyX (3M ESPE), 2-MultiLink (Ivoclar), and 3-SpeedCEM (Ivoclar).

Methods: Eighteen (18) extracted human molars were prepped for all-ceramic crowns as follows: 1mm circumferential shoulder gingival margin, 2mm occlusal reduction, rounded internal angles, and less than 20 total occlusal convergence. Teeth were placed in full dentate typodonts and scanned with E4D optical laser CAD/CAM system. Crowns were cemented according to manufacturer's instruction, under 100N load. Samples were thermocycled for 2,500 cycles between 5C-55C, immersed in 50% w/v ammoniacal silver nitrate solution for three hours, then exposed in photo developing solution for sixteen hours. Samples were embedded in acrylic, sectioned buccal-lingually, and examined under magnification. A microleakage scale of 04 was used. 0=no microleakage; 1=up to 25% microleakage to axial wall; 2=up to 50%; 3=up to 75%; 4=100% penetration to axial wall. The frequency of each microleakage score was tabulated for all combinations of product and leakage location. Generalized estimating equations were used to analyze the results. A P-value<0.05 was considered statistically significant. SAS 9.2 was used in all analyses.

Results: Samples above the CEJ exhibited greater microleakage than below; the difference was statistically significant (P=0.04). The difference between products was not statistically significant (P=0.12).

 

Group

CEJ

0

1

2

3

4

Total

1

Above

1(16.7%)

0(0%)

1(16.7%)

3(50.0%)

1(16.7%)

6(100%)

Below

2(33.3%)

1(16.7%)

1(16.7%)

0(0%)

2(33.3%)

2

Above

2(33.3%)

2(33.3%)

1(16.7%)

1(16.7%)

0(0%)

6(100%)

Below

4(66.7%)

2(33.3%)

0(0%)

0(0%)

0(0%)

3

Above

1(16.7%)

1(16.7%)

2(33.3%)

1(16.7%)

1(16.7%)

6(100%)

Below

4(66.7%)

1(16.7%)

1(16.7%)

0(0%)

0(0%)

Conclusions: With current self-adhesive luting cements, all-ceramic crown marginal preparations should be seated on dentin to prevent marginal leakage.

 

This abstract is based on research that was funded entirely or partially by an outside source: Ivoclar vivadent

Keywords: Cements, Ceramics, Crowns, Dental materials and Microleakage
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