Authors performed a prospective study in 100 patients with chronic anterior disc displacement without reduction. Patients with subjective problems lasting less than one year were assigned as group A ( N = 50) and patients with problems lasting more than one year were group B ( N = 50). 25 patients from group A and 25 patients from group B underwent arthrocentesis, 25 patients from group A and 25 patients from group B underwent arthroscopical lavage. Good result for both methods were pain in value 0–1 (pain score 0–5) and mouth opening minimally 30 mm (interincisivaly).

Group A – effect of arthrocentesis was 75%, effect of arthroscopical lavage was 82%, group B – effect of arthrocentesis was 64%, effect of arthroscopical lavage was 80%.

In conclusion, almost all patients with chronic anterior disc displacement without reduction benefited from lysis and lavage of the temporomandibular joint. Patients with shorter history of subjective problems benefited from the treatment more than patients with longer history.

Conflict of interest: None declared.