Physical and Chemical Characterization of Experimental Newly Formulated Resin Infiltrated Lithium Disilicate Ceramic Network versus Resin Infiltrated Feldspathic Ceramic Network(An in-vitro study)

Abstract Background polymer infiltrated ceramic network is hybrid dental ceramic that mimic the properties of tooth structures, unfortunately commercially available PICN still present limitations such as low strength thus, the current study was assigned to prepare resin infiltrated lithium disilicate ceramic network (PILN) and compare with commercially available PICN regarding microstructure and biaxial flexural strength. Methodology: a fine powder of lithium disilicate was produced by grounding IPSe.max CAD/CAM blocks, a porous lithium disilicate ceramic networks containing 25% (PILN-25) and 20% (PILN-20) porosity were produced by firing at 820OC and 830OC respectively. Resin was infiltrated and polymerized to form a dense PILN. A total of 69 specimens were prepared and assigned into three groups (n = 23) according to the type of ceramic used in fabrication of the ceramic network. The comparable group was Enamic, while the intervention groups were (PILN-25) and (PILN-20). For two intervention groups, porosity and density were measured before and after resin infiltration using helium pycnometer (n = 3 at each stage). SEM for microstructure analysis (n = 9) and One specimen was examined under FESEM for better visualization of the crystalline phases. Another three specimens (n = 3) in each group were assigned for XRD testing and lastly ten specimens for each group (n = 10) were subjected to biaxial flexural strength test. The statistical significance level was set at p ≤ 0.005. Results There was statistically significant difference in biaxial flexural strength, PILN-20 recorded the highest significant strength followed by PILN-25 and Enamic. PILN-25 showed higher porosity% than PILN-20 and the porosity decreased after resin infiltration. PILN-20 showed higher density than PILN-25 and density increased after resin infiltration. XRD revealed the presence of lithium disilicate crystals in both PILN-25 and PILN-20. SEM revealed highly interlocked ceramic and polymeric networks. FESEM revealed the presence of spherical lithium disilicate crystals. Conclusion PILN is a new type of hybrid ceramic material with enhanced mechanical properties. Clinical implication: PILN can be used as a promising CAD/CAM block to make high strength high esthetics dental restorations.