Microleakage of class II packable resin composite lined with flowable composite and resin modified glass ionomer cement : an in vitro study

Abstract EN

Background : packable composites most commonly used as posterior restorative materials, however, disadvantages like polymerization shrinkage limited their use, so the aim of this an in vitro study was to investigate the micro leakage of posterior packable composite(Filtek™ P-60) using different liner materials ; flowable resin composite(Filtek™ Flow) and resin modified glass ionomer cement (Vitrebond TM 7150) using open sandwich technique at the proximal box of class II preparation located above the cemento-enamel junction (CEJ)in enamel.

Materials and Methods : Twenty four recently extracted human upper premolars were prepared with standardized Class-II cavities as follows; Occlusal Outline Form: 2mm in bucco-lingual width and 1.5 mm in depth measured from occlusal fissure to pulpal floor.

Proximal Boxes : the depth of the proximal box from the proximal cavo-surface margin to the axial wall was 2mm, so as the bucco-lingual width (2mm).

The proximal box margin located 1 mm coronal to the CEJ (in enamel).

The teeth were assigned into 3 groups (n = 8) : Group-I (control) : acid etching (H3PO4) + bonding agent (Adoper Single Bond 2 Adhesive) + posterior packable composite (Filtek™ P-60), Group-II (RMGIC) : acid etching + resin modified glass ionomer cement (Vitrebond TM 7150) + posterior packable composite ; Group-III (Flowable) : acid etching + bonding agent + flowable composite (Filtek™ Flow) + posterior packable composite.

The teeth were immersed in distilled water at 37ºC for 24 h., then thermo cycled (1000X, 5°-55°C, 30 sec.

dwell time) and immersed in 1 % methylene blue solution for 24 h., after that the teeth were sectioned longitudinally in mesiodistal direction and dye penetration in millimeters were measured in each cavity by using stereomicroscope.

Data obtained were analyzed using ANOVA and LSD tests at 0.05 significance level.

Results : the micro leakage of posterior packable composite (group-I) significantly (P<0.05) decreased by the two liners used (group-II and group-III), but there is no statistically significant differences (P > 0.05) in enamel micro leakage in respect to dye penetration were detected between the two liners used (group-II and group-III), with the association flowable composite Filtek flow (group-III) showing the best results.

Conclusion : the use of flowable composite (Filtek™ Flow) and resin modified glass ionomer(Vitrebond TM 7150) in the open sandwich technique decrease the micro leakage of posterior packable composite(Filtek™ P-60) with margin located in enamel surface and better results with flowable composite.