IADR Abstract Archives
CAD Marginal Fit Comparison of Lithium Silicate and Lithium Disilicate
Objectives: To evaluate the marginal fit of lithium silicate (LS-- CeltraDuo CAD) and lithium disilicate (LD-- e.max CAD) full contour crowns pre-cementation, post-cementation and post cyclic fatiguing. Ho is there will be no difference in marginal fit between CAD materials nor at measurement intervals.
Methods: 20 human mandibular molars were randomly assigned to 2 groups (n = 10); LD and LS. All specimens were prepared using a lathe device, following LD/LS CAD crown guidelines. Crowns were fabricated for specimens according to their group with a chairside CAD/CAM system (CEREC Omnicam, SW4.5, MCXL). Crystallization for LD and firing-cycle for LS accomplished (Programate P700). Pre-cementation marginal gap measurements recorded for all specimens. Crowns were adhesively luted (5% HF/silane/RelyX Unicem2). Manufacturer recommendations were followed for all materials. Post-cementation measurements made. After 24h storage (37°C/98% RH) specimens were fatigued in a dynamic cyclic loading machine (Sabri Dental); 100 N, 100,000 cycles at 2 Hz in 21°C distilled water. Post-fatiguing measurements made. To acquire measurements, specimens were placed in a horizontal jig and rotated in 10° increments (measured at 36 points) using a digital microscope (Hirox KH-8700, set at 100x optical zoom). Statistical Analysis: Friedman and Mann-Whitney
U Test (p=0.05).
Results: No statistical differences were found between pre-cementation, post-cementation and post-fatigue for either materials. No statistical differences were found between materials at the 3 measurement intervals. Failed to reject the Ho.
Conclusions: Under the conditions of this study, there are no difference in marginal fit between LD and LS crowns. Furthermore, fatiguing did not affect gap size.
Methods: 20 human mandibular molars were randomly assigned to 2 groups (n = 10); LD and LS. All specimens were prepared using a lathe device, following LD/LS CAD crown guidelines. Crowns were fabricated for specimens according to their group with a chairside CAD/CAM system (CEREC Omnicam, SW4.5, MCXL). Crystallization for LD and firing-cycle for LS accomplished (Programate P700). Pre-cementation marginal gap measurements recorded for all specimens. Crowns were adhesively luted (5% HF/silane/RelyX Unicem2). Manufacturer recommendations were followed for all materials. Post-cementation measurements made. After 24h storage (37°C/98% RH) specimens were fatigued in a dynamic cyclic loading machine (Sabri Dental); 100 N, 100,000 cycles at 2 Hz in 21°C distilled water. Post-fatiguing measurements made. To acquire measurements, specimens were placed in a horizontal jig and rotated in 10° increments (measured at 36 points) using a digital microscope (Hirox KH-8700, set at 100x optical zoom). Statistical Analysis: Friedman and Mann-Whitney
U Test (p=0.05).
Results: No statistical differences were found between pre-cementation, post-cementation and post-fatigue for either materials. No statistical differences were found between materials at the 3 measurement intervals. Failed to reject the Ho.
Conclusions: Under the conditions of this study, there are no difference in marginal fit between LD and LS crowns. Furthermore, fatiguing did not affect gap size.
IMAGES
3182861_File000000.jpg
3182861_File000000.jpg