Abstract
BACKGROUND: Polymer infiltrated ceramic network (PICN) is a hybrid dental ceramic that mimics the properties of tooth structures. Unfortunately, commercially available PICN still present limitations such as low strength. Thus, the current study was conducted to prepare polymer infiltrated lithium disilicate ceramic network (PILN) and compare it with commercially available PICN regarding microstructure and biaxial flexural strength. METHODOLOGY: A fine powder of lithium disilicate was produced by grounding (IPS)e.max CAD/CAM blocks. A porous lithium disilicate ceramic networks containing 25% (PILN-25) and 20% (PILN-20) porosity were produced by firing at 820(O)C and 830(O)C respectively. Polymer 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 polymer infiltration using helium pycnometer (n = 3 at each stage). SEM was used for microstructure analysis (n = 9) and One specimen was examined under FESEM for better visualization of the crystalline phases. Additionally, three specimens (n = 3) from each group were assigned for XRD testing and, finally, 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 a statistically significant difference in biaxial flexural strength, PILN-20 recording the highest significant strength followed by PILN-25 and Enamic. PILN-25 showed higher porosity% than PILN-20 and the porosity decreased after polymer infiltration. PILN-20 showed higher density than PILN-25 and density increased after polymer 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 for creating high strength high esthetics dental restorations.