Many studies have attempted to define the relationship between postmenopausal osteoporosis and periodontal disease. Most studies support a positive association between these common diseases; however, many are cross-sectional in nature, include relatively small sample sizes, and have inadequate control of potential confounding factors, such as age, gender, hormone intake, race, and smoking, limiting our understanding of the nature of the relationship between these diseases. Clinical conditions causing low estrogen environments in postmenopausal women allow increased local production of the bone-active cytokine and the progression of periodontal disease. Prospective studies are needed to confirm or refute a causal relation.