Effect of Aging on Marginal Adaptation of Different Resin-Matrix Ceramics Inlays: In Vitro Pilot Study

To evaluate and compare the marginal adaptation of two resin-matrix ceramic inlays and assess the influence of aging.

Fourteen intact mandibular second molars were prepared for inlays and randomly divided into two groups (n = 7): polymer-infiltrated ceramic (Vita Enamic) and resin nano-ceramic (Lava Ultimate). Inlays were fabricated using CAD/CAM technology and cemented with dual-cure self-adhesive resin cement. All specimens were stored in artificial saliva for 1 year and subjected to 5000 thermocycles. Marginal adaptation was examined under a scanning electron microscope before and after aging. The marginal gap width (MGW) and percentage of continuous margin (%CM) were measured for each surface (occlusal, proximal, gingival) and interface (restoration-cement, cement-tooth). The MGW data were analyzed using ANOVA and t-tests, while chi-square tests assessed %CM (p < 0.05).

Aging and the surface type significantly affected MGW (p < 0.05), with greater values after aging and the gingival region showing the largest gaps. The material type and interface had no significant effect. Moreover, %CM showed no significant differences among variables but demonstrated a significant positive trend with aging in Lava Ultimate restorations.

Within the limitations of the study, the type of resin-matrix ceramic affected marginal adaptation, with polymer-infiltrated ceramics showing a higher marginal gap width than resin nano-ceramics. Aging increased marginal gaps in both material groups, and gingival margins exhibited larger gaps than occlusal and proximal surfaces.

Both tested resin-matrix ceramics achieved clinically acceptable marginal integrity. Aging compromised the marginal seal, especially at gingival margins. Careful selection of material type and attention to finishing, impression taking, and cementation procedures at gingival areas are essential to enhance restoration longevity.