To compare the shear bond strength of orthodontic brackets bonded with a Moisture insensitive primer (Transbond MIP 3M Unitek) against a conventional primer (Transbond XT 3M Unitek) when contaminated with saliva – in vitro study. Bonding of orthodontic attachments with acid etching is the most commonly under taken orthodontic procedure. But there are certain limitations with acid etching procedure like saliva/moisture contamination etching time concentration of adhesive etc. Moisture insensitive primers were introduced to overcome their limitations