Objective: to analyze the prevalence and types of joint sound in temporo-mandibular disorders (TMD).
Subjects and methods: 289 patients, 231 females and 58 males, with TMD were studied, from July, 2001 to April, 2002 (age ranging from 5 to 88 years old - mean 36.2). The sounds in TMJ were evaluated by palpation during opening, closing and protrusive movements of the mandible. The moment and phase of sound occurence, and its elimination in the protrusive movement were observed in each exam..
Results: 116 (40%) patients presented joint sound, being bilateral in 70 (60%), unilateral to right side in 39 (33%), and unilateral to left side in 31 (27%). 108 (93%) patients presented the sound on the same side as the pain complaint while being opposite to the clinical complaint in only 8 (7%). 41 (35%) patients presented it at mouth opening, 11 (9%) at closing, and 58 (50%) at both opening and closing movement of the mandible. It occurred at the exact same phase of movements in 8 (7%), being eliminated by protrusion of mandible in only 2. Among the other 50 cases, in which the sound occurred in different phases of movement, half of them were eliminated with a protrusive maneuver of the mandible.
Conclusion: The present study showed a high prevalence of TMJ sound in patients with TMD.. The matching sides of occurrence with pain complaint suggest its relevance in the mechanism of TMD. Additionally, the high prevalence of joint sound exclusively on mouth opening indicates the need to include this modality in the current TMD classification, for which no provision is made.