Effect of immediate dentine sealing on the aging and fracture strength of lithium disilicate inlays and overlays

• Published in: Journal of the mechanical behavior of biomedical materials 2020-10, Vol.110, p.103906-103906, Article 103906
• Main Authors: Hofsteenge, Jelte W., Hogeveen, Femke, Cune, Marco S., Gresnigt, Marco M.M.
• Format: Article
• Language: English
• Subjects: Aging; Ceramic; Composite Resins; Dental Porcelain; Dental Stress Analysis; Dentin; Flexural Strength; Fracture strength; Humans; Immediate dentin sealing; Inlay; Materials Testing; Molar; Overlay; Resin Cements
• ISSN: 1751-6161; 1878-0180
• DOI: 10.1016/j.jmbbm.2020.103906

The objectives of this study were to compare the in vitro, laboratory aging, fracture strength, failure mode and reparability of molars restored with lithium disilicate inlays and overlays in conjunction with or without immediate dentin sealing (IDS). Forty extracted, sound human molars were selected and divided into four groups: 1) Inlays with IDS; 2) Inlays without IDS; 3) Overlays with IDS; 4) Overlays without IDS. Standard MOD preparations were made (3 mm wide, 5 mm deep) and in groups 2 and 4, all the cusps were reduced by 2 mm. Directly following tooth preparation, IDS was applied in specimens belonging to groups 1 and 3. The indirect restorations were luted with a heated composite. The restored teeth were subsequently challenged during aging (1.2 million cycles) and thermocycling loading (8000 cycles, 5–55 degrees C). Subsequently, the fracture strength was tested by a load to failure test at 45°. A failure analysis was performed using light- and scanning electron microscopy. The results were analyzed using two-way ANOVA and a Fisher exact test. Mean fracture load + SD (N) were: Group 1 (n = 12): 1610 ± 419; Group 2 (n = 12): 1115 ± 487; Group 3 (n = 12): 2011 ± 496; Group 4 (n = 12): 1837 ± 406. Teeth restored with an onlay were stronger than those restored with an inlay restoration (p