Introduction: Progressive condylar resorption has been described for many years. Because condylar resorption favors women over men, many have thought that a prominent systemic factor for the pathogenesis of this disease might be related to sex hormones.
Methods: Over a 3-year period, 27 women without autoimmune disease came to our office for orthognathic surgical correction of their skeletal deformity secondary to severe condylar resorption. They all showed radiographic evidence of severe condylar resorption. Sex hormone dysfunction was evaluated, and midcycle serum levels of 17beta-estradiol were measured. Use of exogenous hormones was also documented.
Results: Twenty-six of the 27 women with severe condylar resorption had either laboratory findings of low 17beta-estradiol or a history of extremely irregular menstrual cycles. Of the 27 women, 25 showed abnormally low levels of serum 17beta-estradiol at midcycle. Two subsets were identified in the group with low 17beta-estradiol. The first did not produce estrogen naturally (8 of 27), and the second had low 17beta-estradiol levels secondary to oral contraceptive pill (OCP) use (19 of 27). Of the 19 OCP users, all 19 reported that chin regression and open bite changes occurred after starting OCP use. Nine of the 19 reported these condylar resorption symptoms within the first 6 months of starting the OCP.
Conclusions: Whether induced by ethinyl estradiol birth control or by premature ovarian failure, low circulating 17beta-estradiol makes it impossible for the natural reparative capacity of the condyle to take place in the face of local inflammatory factors. This leads to cortical and medullary condylar lysis.