Abstract: ABSTRACT The purpose of this study was to observe three different aspects related to temporomandibular disorders (TMD): The use of self-medication, the correlation between the instruments for assessing the TMD, and functional outcomes with the use of arthroscopy. In the first study, we prospectively selected 34 patients who responded to Fonseca Anamnesic Index (FAI) and a questionnaire containing questions regarding the sought professional and the use of self-medication. In the second study, 38 medical records of patients were included. The data used were from follow evaluation tools: FAI; Jaw Symptom & Oral Habit Questionnaire (JSOHQ), Helkimo index (HI) and American Association of Orofacial Pain Questionnaire (AAOPQ). In the third study, a review of 42 medical records of patients that underwent arthroscopy of the temporomandibular joint [operative (OA) or lysis and lavage (ALL)] was performed. The presence of pain and maximum interincisal opening were recorded for the follow-up periods of one month and two months. Data were analyzed using SPSS version 18.0. The prevalence of females were identified in all studies (91.2%; 84.6%; 85.7%) and an average age of half of the fourth decade of life. In the first study, 17 patients reported self-medication habit, especially painkillers, more specifically dipyrone. The dentist was the most sought professional (55.5%). There was no association between self-medication and the severity of TMD using the FAI. In the second study, patients classified having a severe TMD in FAI had more positive responses in AAOPQ, with a statistically significant difference when compared to mild TMD patients (p <0.01). A positive correlation was identified between the number of positive responses in AAOPQ and the sum of JSOHQ scores (p <0.01 r = 0.78). Patients classified having a severe TMD in FAI had higher scores in JSOHQ, with a statistically significant difference when compared to patients with moderate TMD (p <0.01) and mild TMD (p <0.01). In the third study, 17 patients underwent to ALL and 25 to OA. There was no statistically significant difference in the improvement of maximal mouth opening regarding the artroscopic procedure performed (OA = 2.24 mm; ALL = 1.92 mm). For both treatments, the preoperative maximal mouth opening is smaller than the postoperative in the one and two months of follow-up. Two patients that received ALL remained with pain after two months of follow-up. From the studies carried, it is possible conclude that: self-medication seems to have a high prevalence in patients with TMD, however this practice does not seem to change the severity of the disease at initial consultation; there was a congruence between the results of the assessment instruments used for DTM, then the choice should be based on the clinic and research purposes; Arthroscopy appears to alleviate the pain of patients unresponsive to conservative treatment, however the improvement of maximum mouth opening was small regardless of the technique used (AO and ALL) Advisors/Committee Members: UNIVERSIDADE ESTADUAL DE CAMPINAS (CRUESP), Moraes, Marcio de, 1966- (advisor), Universidade Estadual de Campinas. Faculdade de Odontologia de Piracicaba (institution), Programa de Pós-Graduação em Clínica Odontológica (nameofprogram), Andrade, Eduardo Dias de (committee member), Villas, Marcos Vianna (committee member), Ilg, Jan Peter (committee member), Homsi, Nicolas (committee member).