Effect of Two Different Surface Treatments on Retention of Cosmopost with Two Different Core Materials

Figures & data

Figure 1 Shows cosmopost.

Table 1 Shows Composition, Properties & Manufacturer of Cosmopost

Composition	(In weight %)
	ZrO2 + HfO2 + Y2O3 > 99% Y2O3 4.5–5.4%
	HfO2 < 5% Al2O3 < 0.5%
Physical Properties	Density > 6.0 g/cm3
	Porosity (open) 0%
	Flexural strength (4-point) > 800 N/mm2 Coefficient of thermal expansion (100°- 500°) 10.0 ± 1.0 µm/(mK)
Manufacture	Ivoclar-Vivadent, Liechtenstein.

Figure 2 Shows IPS empress cosmo ingot.

Table 2 Shows Composition, Properties & Manufacturer of IPs Empress

Composition	(In weight %) SiO2 (54–59%)
	ZrO2 (15 – 19%)
	Al2O3 (3 – 7%)
	P2O5 (4 – 7%)
	Li2O (7 – 10%)
	Na2O (2 – 5%)
	K2O (3 – 7%)
	F (0.5 – 2%) + Pigments (0 – 2%)
Physical Properties	Flexural strength > 100 N/mm2 Chemical solubility < 2000 µg/cm2 Coefficient of thermal expansion (100°- 500°) 9.5 ± 0.5 µm/(mK)
	Transformation temperature 545 ± 10°C Fracture toughness [0.5–2.75 MPa] Modulus of elasticity [95 GPa]
	Vickers hardness [5800 MPa]
	Press temperature 915 −920/1679–1688 [°C/°F]
Manufacture	Ivoclar-Vivadent, Liechtenstein.

Figure 3 Shows 3M™ filtek composite.

Figure 4 Flow diagram of samples grouping.

Figure 5 Bar chart representing mean values for comparison between surface roughness of different surface treatments in microns.

Table 3 Comparison Between Ra Values of Surface Treatments of Composite in Microns

Control		Silica Coating		Sandblasting		P-value
Mean	SD	Mean	SD	Mean	SD
0.747^a	0.003	0.635 ^b	0.006	0.645^b	0.005	<0.001*

Notes: ^aUntreated Cosmoposts (Control). ^bCosmopost treated with silica coating, sandblasting, *Significant at P ≤ 0.05, statistically different letters are significantly different.

Table 4 Resulted Regression Model Effect on Mean Push-Out Bond Strength of Different Variables in MPa

Source of Variation	Type III Sum of Squares	Df	Mean Square	F-value	P-value
Core material	1541.1	1	1541.1	93.2	<0.001*
Surface treatment	322.1	2	161	9.7	0.004*
Core material x Surface treatment	197.6	2	98.8	6	0.020*

Note: *Significant at P ≤ 0.05.

Abbreviation: df, degrees of freedom = (n-1).

Figure 6 Row graph displaying mean values for contrast between the bond strength of the two core materials (in MPa).

Table 5 Comparison Between Push-Out Bond Strength of Core Materials (in Mpa) Regardless of Surface Treatment

Composite		IPS Empress		P-value
Mean	SD	Mean	SD
15.8	2.5	36.4	9.7	<0.001*

Note: *Significant at P ≤ 0.05.

Figure 7 Row graph which shows the mean values for comparing the push-out bond strength of the different surface treatments in MPa.

Table 6 Comparison Between Push-Out Bond Strength of Surface Treatments (in Mpa) Regardless of Core Materials

Control		Silica Coating		Sandblasting
Mean	SD	Mean	SD	Mean	SD	P-value
27.2^a	14.9	28.3a	13.6	18.5b	5.9	0.004*

Notes: ^aUntreated Cosmoposts (Control) and Cosmoposts treated with silica coating. ^bCosmopost treated with sandblasting, *Significant at P ≤ 0.05, Statistically, different letters differ significantly.

Table 7 Comparison Between Push-Out Bond Strength of Different Variables’ Interactions in MPa

Core material	Surface Treatment	Mean	SD	P-value
Composite	Control	14.5^c	0.9	0.020*
	Silica coating	18.4^c	1.2
	Sandblasting	14.6^c	2.8
IPS Empress	Control	39.9^a	8.2
	Silica coating	43.2^a	0.5
	Sandblasting	24.3^b	3.3

Notes: ^aControlled and silica coating cosmopost attached to IPS empress core. ^bSandblasted cosmopost attached to IPS empress core. ^cControlled, silicacoated, sandblasted cosmopost attached to composite core.*Significant at P ≤ 0.05, Statistically, different letters differ significantly.

Figure 8 Row graph displaying mean values of the push-out bond strength of a different interaction (in MPa).

Figure 9 Photomicrograph of untreated zirconia dowel surface (original magnification 300).

Figure 10 Photomicrograph of sandblasted cosmopost surface.

Figure 11 Photomicrograph of silica coated cosmoposts surface.

Figure 12 Representative SEM of control group attached to composite core (original magnification 33) demonstrating adhesive type of failure.

Figure 13 Representative SEM of sandblasting treated group attached to composite core (original magnification 33) demonstrating adhesive type of failure.

Figure 14 Representative SEM of silica coating treated group attached to composite core (original magnification 33) demonstrating adhesive type of failure.

Figure 15 Representative SEM of control group attached to IPS empress core (original magnification 33) demonstrating adhesive/Cohesive type of failure.

Figure 16 Representative SEM of sandblasting treated group attached to IPS empress core (original magnification 33) demonstrating adhesive/Cohesive type of failure.

Figure 17 Representative SEM of silica coating treated group attached to IPS empress core (original magnification 33) demonstrating increased cohesive failure and less type of adhesive failure.