An oral irrigator tip defines a main fluid passage and first and second side fluid passages on a opposite sides of the main fluid passage. Each side fluid passage has an inlet and an outlet both in fluid communication with the main fluid passage. First and second island structures may be formed between the main fluid passage and respective side fluid passages. Fluid flow through the main fluid passage is drawn to sidewalls of the islands due to the Coanda effect. At least a portion of the fluid stream entering the main fluid passage is diverted through the first and second side fluid passages to create feedback loops that push the fluid flow through the main fluid passage alternately from side to side. An oscillating fluid stream is thereby delivered from the oral irrigator tip.
