The objective of this study was to compare the effectiveness of essential oil mouthrinse and interdental brush for oral hygiene in orthodontic patient. 90 patients, with fixed orthodontic appliances, were divided into 3 groups(Group 1: patients who had only used toothbrush, group 2: toothbrush + essential oil mouthrinse, group 3: toothbrush + interdental brush). Then, plaque index(PI) and gingival index(GI) were evaluated at before(T0), 3 weeks after(Tl) and 6 weeks after(T2) the experiment. The present study revealed the following conclusions: (1) There was statistically significant decrease in PI and GI of groups 2 and 3 comparing to those of group 1 during 6 weeks.(p<0.05) (2) There was no significant difference in the level of decrease in PI and GI between group 2 and group 3.(p<0.05) The present study thus implied that use of mechanical or chemical aid such as interdental brush and mouth rinse in addition to toothbrushing may help maintaining oral hygiene in patients undergoing fixed orthodontic treatment for prolonged duration.