Predisposing and Precipitating Factors in Temporomandibular Disorders

The hyperdivergent facial profile presents the orthodontist, oral surgeon, and restorative dentist with problems that might not be solvable with any one or all of our specialties. This article will review the literature on the possible predisposing and precipitating factors that might contribute to hyperdivergent facial profiles. We will attempt to correlate facial morphology as it might relate to disk displacement (DD) and degenerative joint disease (DJD). Human and animal studies will be reviewed that support these observations. Our hypothesis is that this hyperdivergent facial profile is often associated with bilateral DD and/or DJD. The effect of DD/DJD in animal and human studies and the effect of cartilage degeneration on hard and soft tissues will be reviewed. The presence of catabolic biological markers of joint degeneration (interleukin-1β, interleukin-6, matrix metalloproteinases, tumor necrosis factor-α, C-reactive protein, synovial fluid proteins) and anabolic markers (tissue inhibitors of metalloproteinases, interleukin-4, interleukin-10, interleukin-13) will be discussed. Epidemiologic studies suggest that in patients presenting with temporomandibular joint pain, there is a strong correlation between the disorder and severe mandibular retrognathia in adult women (odds ratio, 6.3). Human cephalometric studies will demonstrate that bilateral DD/DJD is highly correlated with the hyperdivergent facial profile. Follow-up orthognathic surgery studies suggest that correction might be unstable. This review will present a compelling case that the hyperdivergent facial profile is strongly correlated with bilateral DD and/or DJD. Clinicians should be aware of these findings and convey this information to patients presenting for dental treatments.