0054 Effect of Cavity Configuration on Adhesion of a Silorane Composite
A. VAN ENDE, J. DE MUNCK, A. MINE, P. LAMBRECHTS, and B. VAN MEERBEEK, Leuven BIOMAT Research Cluster, Catholic University of Leuven, Leuven, Belgium

Objectives: Polymerization shrinkage of a composite in a high configuration factor (C-factor) cavity leads to high polymerization stress. In this study, the effect of C-factor (flat vs. cavity) and composite shrinkage (high- vs. low-shrinking) on the micro-tensile bond strength (µTBS) to dentin was investigated.

Methods: A conventional methacrylate-based composite (Z100, 3M ESPE) and a low-shrinking silorane-based composite (Filtek Silorane, 3M ESPE) were applied to standardized occlusal class-I cavities (4x4x2.5 mm) and flat surfaces using the Silorane System Adhesive (3M ESPE). After one week of water storage, the teeth were sectioned to 1x1 mm sticks by an automated, water-cooled diamond saw (Accutom, Struers). For each group, at least 5 teeth were used, and from each tooth, the 4 central sticks were selected for µTBS-testing.

Results:

Z100

Filtek Silorane

Flat

Cavity Bulk1

Flat

Cavity Bulk1

Cavity Layers2

Cavity Flowable3

Cavity Warm4

Mean ± SD

ptf/n

30.2A,B ± 11.1

0/22

26.6A,B ± 17.3

0/19

33.4A ± 11.2

0/20

13.2C,D ± 9.2

2/18

21.5B,C ± 10.1

0/18

23.7A,B ± 7.9

0/20

4.2D ± 6.8

16/25

Means with the same superscript are not significantly different from each other (ANOVA and Tukey-Kramer tests; p<0.05); n = total number of specimens; ptf = pre-testing failures and were recorded as 0MPa. 1Cavity filled and cured in bulk. 2Composite was applied and cured in three layers. 3Before composite application, a thin layer of flowable composite (Experimental Silorane Flow, 3M-ESPE) was applied and cured. 4Composite was heated to 54°C.

Conclusions: Using Silorane System Adhesive, Z100 as well as Filtek Silorane were equally well bonded to dentin. Bulk-filling of the cavities with Filtek Silorane decreased the µTBS. This was primarily caused by poor adaptation between the adhesive and composite, as evidenced by failure analysis using scanning electron microscopy (Fe-SEM). This decreased strength could partially be restored by application in layers or prior application of a flowable resin.

Seq #11 - Adhesion/Dentin/Luting/Siloranes
11:30 AM-1:00 PM, Wednesday, September 10, 2008 Queen Elizabeth II Conference Centre Poster Hall 1

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