4.2 Prevalence and manifestation age
The most common age range of patients is 10-30 years at the initial onset of torus development, but its growth may continue until the seventh decade of life.9, 10 There is a considerable variation in the prevalence of tori among populations of different ethnicity and gender. One study of 448 female residents of Washington, D.C., found that tori were present in 35% of African Americans, 32% of Caucasians, 30% of Hispanics, 38% of Asians, and 20% of Native Americans.2
Another investigation involving patients from Southern States of the United States revealed that 25% of Caucasian men and 24% of women had TM, whereas TMAX was present in 22% of men and 40% of women, respectively. In comparison, African Americans had TM in 18% of men and 13% of women, and they had TMX in 14% of men and 45% of women.1
A high incidence of tori has been reported among the Asian population. Morita and associates found TM in 58% of healthy students at Hiroshima University in Japan.11 Another study involving 1,520 dental patients in Thailand showed prevalence rates of 60.5% for TP, 32.2% for TM, and concurrent tori in 23.2% of the cases.12 Most of the published large series show a female predominance for TP and a slight male predilection for TM.10, 13