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 5°C-55°C, 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 0–4 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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