In this paper, the authors review the rationale and history of mandibular repositioning procedures in relation to temporomandibular disorders (TMDs) as these procedures have evolved over time. A large body of clinical research evidence shows that most TMDs can and should be managed with conservative treatment protocols that do not include any mandibular repositioning procedures. Although this provides a strong clinical argument for avoiding such procedures, very few reports have discussed the biologic reasons for either accepting or rejecting them. This scientific information could provide a basis for determining whether mandibular repositioning procedures can be defended as being medically necessary. This position paper introduces the biologic concept of homeostasis as it applies to this topic. The continuing adaptability of teeth, muscles, and temporomandibular joints throughout life is described in terms of homeostasis, which leads to the conclusion that each person's current temporomandibular joint position is biologically “correct.” Therefore, that position does not need to be changed as part of a TMD treatment protocol. This means that irreversible TMD treatment procedures, such as equilibration, orthodontics, full-mouth reconstruction, and orthognathic surgery, cannot be defended as being medically necessary.