Santrauka:
Paruošus 40 specializuotų ličio disilikato mėginių karšto presavimo metodika (4 skirtingų gamintojų), buvo analizuojamas pirminis poliruotų paviršių šiurkštumas SEM ir AFM mikroskopais. Tuomet atlikta 120 000 ciklų kramtymo simuliacija su cirkonio oksido keramika. Po kramtymo simuliacijos, SEM ir AFM mikroskopais analizuotas poliruotų mėginių paviršiaus kiekybinis bei kokybinis pokytis.
Description:
Aim of the work – to evaluate pressable lithium disilicate polished surface variation after chewing simulation. Relevance of the problem: lithium disilicate ceramic restorations require high-quality surface polishing. After many chewing cycles material wear and surface roughness increases, there are greater risk of material longevity. Material and methods: four lithium disilicate glass ceramic materials (HASS „Amber Press“, Ivoclar Vivadent IPS „E.max Press“, GC Initial „Lisi Press“ and Cendres+Metaux SA „Livento Press“) were used in this study to evaluate polished surface variation after chewing simulation. Fourty standardized specimens (h=12 mm; d=4,8 mm) were made using hot pressing technique and divided in into four groups by manufacturer (A, E, G and L groups, n=10). All 40 specimens were prepared using same polishing protocol. Polished surface roughness (Ra) were tested (one specimen of every group, selected randomly) before and after chewing simulation using scanning electron microscope (SEM) in 20.0 μm radius and atomic force microscope (AFM) in 5.0 μm radius. 50% of specimens were subjected to the SD Mechatronik CS-4.2 (Germany) chewing simulator (120 000 cycles, 5kg/49N weight) againt zirconia antagonists, which feature flexural strength of 1400 MPa (ZirkonZahn „ICE ZIRKON TRANSLUCENT“, Italy). Results were evaluated optically and statistically. Results: using SEM before chewing simulation optically visible, lithium disilicate polished surface is supremely smooth. After 120 000 chewing cycles there are visible fractures, cracks and other antagonistic effects appear on the surface of the tested samples. Analyzing AFM rezults, in all four groups (A, E, G& L) achieved extremely low values of 4,74-7,12 (±1,083) nm. After chewing simulation the average surface roughness of tested specimens was 74,44 (±1,97) nm. Lowest average value (72,477) nm after chewing simulation were measured on Ivoclar Vivadent IPS „E.max Press“. Minimum and maximum values were estimated on HASS „Amber Press“ (18,241-180,574) nm specimens.
