Microleakage of class II composite using different etching techniques

الملخص EN

Background : micro leakage in the gingival floor of class II composite restorations can compromise the marginal adaptation of the filling material to the cavity edges.

The aim of this study was to evaluate the effect of different etching techniques on micro leakage of class II Composite filling.

Materials and methods : Sixty extracted caries-free human premolars were randomly divided into six groups according to etching technique.

In group A and B the dentin of the cavities were etched with 35 % phosphoric acid gel, in group C and D the dentin of the cavities were irradiated using a 320 μm Nd : YAG laser beam, in group E and F the dentin surfaces were initially treated with the laser and then etched as in group A and B with 35 % phosphoric acid.

Proximal class II cavities were prepared in all samples with the gingival floor one millimeter below the CEJ.

Cavities were restored according to research protocol.

The samples were subjected to 2500 thermal cycles (5-55oC).

Immersed in 0.5 % basic fuchsine solution embedded in epoxy resin and cut centrally.

Micro leakage was scored and collected data were statistically analyzed using one way analysis of variance.

Results : more micro leakage was detected in group C (p < 0.05 ; variance analysis).

The laser beam and acid-etching showed no advantage compared to the acid-etching alone (p > 0.05).

Using the incremental technique significantly decreased micro leakage (P < 0.02).

Conclusion : The Nd : YAG laser irradiation in cl II composite does not constitute an alternative to acid-etching.

Samples restored with the incremental technique, and cavities etched with 35 % phosphoric acid gel had the least dye penetration and micro leakage.