In-vitro comparison of microleakage in 3D-printed inlay restorations and indirect composite inlay restorations using different resin cements

Aim: The aim of this in-vitro study was to compare the microleakage of inlay restorations fabricated using 3D printing and luted with two different resin cements, with that of indirect composite inlay restorations, both in the presence and absence of aging. Material and Method: In this study, standardized Class II (mesio-occlusal) cavities were prepared on 108 extracted human molar teeth (n=9) that were free of caries. Inlay restorations were fabricated using two different 3D printing resins [(NextDent C&B MFH, NextDent B.V., the Netherlands) and (Saremco Print CrownTec, Saremco, Switzerland)] and one indirect resin composite (GC Gradia Plus, GC, Japan). These restorations were luted using two different resin cements [(Panavia V5, Kuraray Noritake Dental, Japan) and (Variolink Esthetic LC, Ivoclar Vivadent AG, Liechtenstein)]. Following finishing and polishing procedures, half of the specimens underwent thermal cycling for 5,000 cycles to simulate aging, while the other half received no aging treatment. All specimens were immersed in 2% basic fuchsin solution for 24 hours. The specimens were sectioned longitudinally in the occluso-gingival direction to evaluate marginal leakage. Dye penetration was recorded under 4X magnification and scored accordingly. The obtained data were statistically analyzed. Categorical data were evaluated using Pearson's Chi-Square test and Fisher's Exact test. Results: As a result of the analyses, a statistically significant relationship was found between the microleakage scores and the aging condition (p < 0.05). While the majority of non-aged specimens exhibited a score of 0, the incidence of scores 1–3 increased in the aged specimens. Neither the type of material nor the type of resin cement alone had a significant effect (p > 0.05). However, the effect of aging was statistically significant in the Panavia V5–composite and Variolink–Crowntec combinations (p < 0.05). No statistically significant difference was observed between the occlusal and gingival scores (p > 0.05). Conclusion: The findings revealed that the aging process led to a statistically significant increase in microleakage, whereas the type of resin cement and restorative material used did not result in a statistically significant difference in this regard. These results suggest that the choice of material and cement alone may not be sufficient to determine microleakage outcomes. However, when considered in conjunction with environmental factors such as aging, they may provide more comprehensive insights into the sealing performance of restorations. Keywords: 3D printing, inlay restoration, microleakage, aging, resin cement, indirect composite