Accademia Italiana di Conservativa - CONSEURO 2000 - Abstract - Influence Of Curing Technique On Leakage Of Class II Restorations

Influence Of Curing Technique On Leakage Of Class II Restorations

A. Vichi*, C. L. Davidson And M. Ferrari*

(*University Of Siena, Italy; ACTA, University Of Amsterdam, The Netherlands; Tufts University, Boston, MA, USA)

To reduce high tensile forces (stress) along the interfaces between tooth and restorative material in Class II restorations, two main directions can be followed: placement of an elastic liner as stress-absorbing layer or application of polymerization systems capable of reducing curing contraction stresses. Aim of this study was to compare the traditional stratified technique with the sandwich technique as well as the role of three different curing techniques. 90 extracted molars, free from caries and restorations, were selected for the investigation. The sample cavities were prepared following a standardized pattern in which the Class II OM cavity had a length of 3 mm and a width of 2 mm occlusally. The proximal box had an axial depth of 1.5 mm and a buccolingual width of 4 mm. The cervical margin was located 1 mm below the CEJ. After cavity preparation, the samples were randomly divided in 9 groups (n=10) and restored as follows.

Group 1: One Step and Pyramid (Bisco Inc., USA) with traditional stratified technique;
Group 2: One Step and Pyramid with Pulse & Cure technique (V.I.P. - Bisco);
Group 3: One Step and Pyramid with Plasma Arc lamp (Apollo 95E - DMD - USA);
Group 4: One Step, Aelite Flo and Pyramid with traditional stratified technique;
Group 5: One Step, Aelite Flo and Pyramid with Pulse technique (V.I.P.);
Group 6: One Step, Aelite Flo and Pyramid with Plasma Arc lamp (Apollo 95E );
Group 7: Scotchbond 1, P60 with traditional stratified technique.
Group 8: Scotchbond 1, P60 with Pulse & Cure technique (V.I.P.).
Group 9: Scotchbond 1, P60 with with Plasma Arc lamp (Apollo 95E ).

After restoration, the samples were immersed in a 2% methylene blue solution for 24h, and then embedded in epoxy resin. Three sections for each sample were made by a water-cooled low speed saw along the crown-apical axis of the teeth. The penetration of the dye was evaluated with a 5-degree score pattern. Kruskal-Wallis statistical analysis and Newman-Keuls mct were performed at 5% significance level. The results showed that occlusally group 2, 4 and 5 had statistically significant differences.

Cervically the statistical pattern was quite complex, but better results were still given from group 2, 4 and 5.

In conclusion, use of flowable resin as elastic liner as well as Pulse & Cure technique can improve sealing performances in the cervical area of Class II restoration. The combination of the two systems didn’t show to further improve results.