ABSTRACT
Objectives: The current project was undertaken to evaluate the adaptation of hybrid composite [Filtek Z 250], packable composite [Filtek P 60] and ormocer-based [Admira] restorative materials with or without flowable liner in class H cavity preparation with enamel and dentin margin before and after load cycling. Methods: This study was carried out on 240 extracted lower molars and divided into six main groups with 40 molars in each group according to the restorative systems used. Where group 1 restored with Filtek Z 250, group 2 Filtek Flow/Filtek Z 250, group 3 Filtek P 60, group 4 Filtek Flow/ Filtek P 60, group 5 Admira and group 6 Admira Flow/Admira. Each group was further subdivided into two subgroups according to the gingival margin location. In the first subgroup the gingival margin was located 1.0 mm above the cemento-enamel junction while in the second subgroup the gingival margin was located 1.0 mm below the CEJ. Respectively, each subgroup was subdivided again into two halves one half subjected to load cycling and the other half not subjected to load cycling. A mechanical loading machine was used to apply a cyclic load of 80-160 N at a 5 cycle/second, for 200.000 cycles following a sinasodal loading curve in a distilled water environment. The marginal and internal gap surface areas were measured on incidental light microscopy setup with an attached digital camera and dedicated computer to acquire digital photomicrographs of sectioned teeth. Statistical analysis was performed using ANOVA [P< 0.05] to determine the effect of restorative material type, location of gingival margin [enamel or dentin], using flowable liner and finally before or after load cycling on the marginal and internal adaptation of the restored samples. Post Hoc Multiple comparison test [P< 0.05] was performed to determine significant intra-group difference of gap surface area of the tested groups
Restults: The analysis of variance showed that the Admira Flow/Admira has the lowest gap surface area with all the tested groups. Also, the restored samples with Filtek Flow or Admira Flow as a liner showed less gap surface area than the restored samples without flowable liner. Enamel margins showed less gap surface area compared to dentin margins and there was no significant difference in marginal and internal ad-aptation between the samples before or after load cycling
Conclusions: Within the limitations of this study, the following conclusions can be drawn: [l]The ormocer-based restorative material [Admira] provides better marginal and internal adaptation than both universal hybrid composite resin [Filtek Z 250] and packable composite [Filtek P 60 ].[2] The quality of marginal and internal adaptation before and after load cycling proved to be influenced by the location of the cavity margins, the enamel margin achieves more adaptation than the dentin margin. [3] Flowable liner could be used to enhance the adaptation of both resin composites and ormocer-based restorative materials.and [4] Load cycling has no significant effect on the adaptation of the restorative materials used in this study
ABSTRACT
The present study was performed to compare the reproducibility of each of the porcelain and composite laminates to the selected shade [A-2]. The effects of the laminate thickness [0.5 mm and 1 mm] and that of the luting resin shades on the final shade of the laminate samples were also investigated. This study was carried out on 84 laminate samples i.e 42 porcelain laminate samples [IPS Corum] and 42 composite laminate samples [Tetric Ceram]. The shade of the laminate materials [porcelain/composite] which was used in fabrication of laminate was A-2. Each laminate sample was square in shape with a side length 10 mm. Half of the laminate samples had 0.5 mm thickness while the other half of the samples had 1 mm thickness. All of the laminate samples were cemented to standardized acrylic substrates. The shade of the substrates was C-4. Cementation of the laminate samples to the substrates was done by using different shades [A-1, A-2, A-3.5] of Aeliteflo and Tetric Flow flowable composites. The color difference between each cemented sample and the A-2 vita lumen shade guide was measured by using a spectro-colorimeter. The porcelain laminate was found to be the most reproducible material to the selected shade, and the statistical analysis revealed that the difference in shade reproducibility was highly significant when compared with composite laminate martial. The laminate samples with 1mm thickness had superior reproducibility than the laminate samples with 0.5 mm thickness. Aeliteflo luting resin was more reproducible to the selected shade than Tetric how luting resin. There was a highly significant relation between the shade of the luting resin and the final shade of laminate