Incidence of Voids in Packable versus Conventional Posterior Composite Resins: An In Vitro Study

Aim. Study aimed to determine effects of flowable composites as liner on marginal and internal voids in MOD composite restorations with dif ferent gingival levels. Methods. 45 molars were prepared for MOD cavities. Finish line was prepared 1 mm apical to mesial, and 1 mm coronal to the cemento-enamel junction on distal. Teeth were restored with: Solitaire; Solitaire + Revolution; Surefil; Surefil + Dyract Flow; Alert; Alert + Flow-it; Amelogen (control); Amalgam (negative control); and Prodigy Condensable. Then resin embedded and sectioned specimens were observed under stereomicroscope to determine the number and size (mm) of voids at margins and within material. Data was analyzed by Kruskal-Wallis analysis of variance and Wilcoxon Signed Ranks Test (α = .05). Results. According to number of voids, there was no significant difference at margins (P>0.05,) but Alert showed significant differences with Solitaire, Amalgam and Solitaire + Revolution at occlusal material (P<0.05) and Solitaire at distal material. According to size, Alert showed differences with Solitaire, Amalgam, Surefil, Surefil + Dyract Flow, also between Aler + Flow-it, and Solitaire at total material. Mesial and distal comparisons were significant in Amalgam (P = 0.042) at material for number, and in Amelogen (P = 0.042) at margin for size of the voids. Conclusion. The number and size of voids of packables did not show difference at restoration margins, within material. Different gingival le vels and flowable usage did not make difference among packables. Usage of flowable with packable in a MOD resin restoration at different gingival le vels did not achieve reduction in the number and size of voids at the margins and internally.