Effect of Lactic Acid Etching on Bonding Effectiveness of Orthodontic Bracket after Water Storage

Table 3

Shear bond strength (MPa) for experimental groups according to the type of etchant [mean (SD*) 𝑛=10].

Etchant	Storage time
	24 hours of water storage^1	6 months of water storage^2
10% lactic acid^a	11.9 (.6)^f	9.4 (.7)^g
20% lactic acid^b	12.2 (.7)^h	10.1 (.6)^i
30% lactic acid^c	6.1 (.6)^j	4.1 (.5)^k
50% lactic acid^d	5.1 (.5)^l	3.1 (.6)^m
37% phosphoric acid^e	8.2 (.6)^n	6.2 (.6)^o

∗SD: standard deviation.
Different superscript numbers represent  significant differences between the shear bond strengths of each storage time (𝑃<.001). Different lowercase letters represent significant differences between the etchant * storage times within each group (𝑃<.001).