Background : Nickel-Titanium (Ni Ti) most recommended for leveling and aligning in iNi Tial stage of orthodontic treatment due to maximum deflection. The application amount of forces on the teeth must be adjusted because the use kawat busur is in direct contact with the saliva for long period. Saliva has effect of decreasing mechanical properties based on the duration of immersion in saliva. The purpose of this study was to evaluate the effect of Ni Ti kawat busurs immersion in artifisial saliva on normal pH to wire deflection at third, fourth, sixth weeks. Method : The method in this study was experimental quasy with cross sectional study design. This study used 12 round kawat busur of Ni Ti superelastic (Ortho Prime) 0,012 inch divided into 3 groups. Each group consisting of 4 specimens was immersed in artificial saliva for third, fourth, sixth weeks before being tested using three point bending method with a Universal Testing Machine. The data result then analyzed using One Way ANOVA followed by Least Significant Difference (LSD) Post Hoc Test. Result : The result of this study showed significant different p<0,05 in deflection third, fourth, sixth weeks. Group was immersed for the longest weeks showed the lowest load deflection.