This study arose from consultations with several patients with Temporomandibular Dysfunction (TMD) and Orofacial Pain (OOP). Many colleagues have the same doubt due to concepts which state that TMD is related to the teeth and not the muscles (80% of TMD). We therefore decided to measure the knowledge of orthodontists in the state of Amazonas about TMD and OOF, in order to compare it with research carried out elsewhere in Brazil and the world. The sample consisted of 98 specialists out of a total of 137 registered with the CRO-AM, assessed using a questionnaire developed at the University of Washington (USA), Korea and Brazil. The translated questionnaire consisted of 35 statements from four areas related to TMD: pathophysiology; psychophysiology; chronic pain; and psychiatric disorders. After collection and tabulation, the data was compared with the opinions of TMD experts on these items. The results were quite alarming and are quoted and discussed in this book. After the research was completed, the author set to work trying to disseminate his truth about TMD, a very preventive and habit-changing truth without extensive, invasive and irreversible procedures.