A dispenser for dispensing a liquid such as a tooth whitening gel can include a plunger and a housing having a first chamber that receives a first arm of the plunger and a second chamber that receives a second arm of the plunger. The housing can further include a first channel in fluid communication with the first chamber, a second channel in fluid communication with the second chamber, and a third channel formed at an intersection of the first and second channels. The housing can further include a static mixer than mixes a first liquid from the first chamber with a second liquid from the second chamber. The plunger may be disposed along a first axis and the third channel may be disposed along a second axis that intersects the first axis at an angle of between 10° and 170°.