IADR Abstract Archives
Correlating Translucency, Light Transmittance, and Cement Conversion in Dental Ceramics
Objectives: The primary objective was to investigate the impact varying thickness and shade of ceramic has on the translucency parameter (TP), light transmission through the material, and degree of conversion (DC) in light-cure resin. The secondary objective was to define a mathematical relationship between sample thickness and TP utilizing Beer’s Law.
Methods: Sample materials varied in material type, shade, and translucency; consisting of lithium disilicate (eMax CAD) shades A1 LT, A1 HT, A4 LT, A4 HT and full contour zirconia (BruxZir Shaded) shades 100 and 550. Five samples for thicknesses ranging from 1.0mm to 2.0mm in 0.25mm increments were prepared, resulting in twenty-five samples per material. The TP was measured using a spectrophotometer (CM-2600D, Konica Minolta). Light transmission through the samples was measured utilizing a resin calibrator (MARC Resin Calibrator, BlueLight) and curing light (Bluephase Style, Ivoclar Vivadent). Resin cement (VarioLink II, Ivoclar Vivadent) was cured for forty seconds through each sample in a mold for a film thickness of 191 microns. DC of the resin was measured using FTIR to compare the area at 1638 cm-1 and 1608 cm-1 peaks of the cured sample to uncured resin.
Results: Increasing material thickness decreased TP, regardless of material type or shade. This relationship was exponential. Two-way ANOVA shows there is a statistically significant difference between thickness, shade, and the interaction between the two. Decreasing TP resulted in a proportional decrease in the average energy of transmitted light.
Conclusions: The TP of the material is primarily influenced by the thickness and type of the ceramic material with an increase in thickness resulting in decreased TP, this relationship is exponential and can be quantified using Beer’s Law. Interestingly, shade does not show a significant impact on TP for the low-translucency formulations of eMax. Increasing TP results in proportional increase in average light transmittance through the material.
Methods: Sample materials varied in material type, shade, and translucency; consisting of lithium disilicate (eMax CAD) shades A1 LT, A1 HT, A4 LT, A4 HT and full contour zirconia (BruxZir Shaded) shades 100 and 550. Five samples for thicknesses ranging from 1.0mm to 2.0mm in 0.25mm increments were prepared, resulting in twenty-five samples per material. The TP was measured using a spectrophotometer (CM-2600D, Konica Minolta). Light transmission through the samples was measured utilizing a resin calibrator (MARC Resin Calibrator, BlueLight) and curing light (Bluephase Style, Ivoclar Vivadent). Resin cement (VarioLink II, Ivoclar Vivadent) was cured for forty seconds through each sample in a mold for a film thickness of 191 microns. DC of the resin was measured using FTIR to compare the area at 1638 cm-1 and 1608 cm-1 peaks of the cured sample to uncured resin.
Results: Increasing material thickness decreased TP, regardless of material type or shade. This relationship was exponential. Two-way ANOVA shows there is a statistically significant difference between thickness, shade, and the interaction between the two. Decreasing TP resulted in a proportional decrease in the average energy of transmitted light.
Conclusions: The TP of the material is primarily influenced by the thickness and type of the ceramic material with an increase in thickness resulting in decreased TP, this relationship is exponential and can be quantified using Beer’s Law. Interestingly, shade does not show a significant impact on TP for the low-translucency formulations of eMax. Increasing TP results in proportional increase in average light transmittance through the material.