Table 2. The means and standard deviations of shear bond strength.

Surface treatments	Mean ± SD
	No-aging ( n = 10)	Aging ( n = 10)
The same superscript indicates no significant difference. Abbreviations: SD, standard deviation; HF, hydrofluoric.
Group 1: Control	7.49 ± 0.98 C	2.93 ± 1.35 D
Group 2: HF	19.44 ± 3.54 A	12.84 ± 2.87 B
Group 3: HF + calcium hydroxide	19.32 ± 2.82 A	13.31 ± 2.97 B
Group 4: HF + calcium carbonate	21.33 ± 2.93 A	11.83 ± 2.34 B
Group 5: HF + calcium gluconate	21.16 ± 3.54 A	14.07 ± 3.31 B
Group 6: HF + ultrasonic	20.69 ± 3.17 A	13.64 ± 2.70 B