Cephalometric study of the changes occurring in the face height following prosthetic treatment. Part II. Variability in the rate of face height reduction

Abstract Differences were found in each of the categories studied. Sex differences. 1. Both the occlusal and rest heights were much greater among men than among women. 2. The occlusal face height among men was increased after the insertion of dentures beyond the pre-extraction rest face height. 3. The decrease of rest face height after extraction and the increase of both occlusal and rest face heights after insertion was greater in men than in women. 4. During the 12 month postinsertion period, the rate of reduction of both the occlusal and rest face heights was slower in men than in women. 5. By the end of the 12 month postinsertion period, both the occlusal and rest face heights in men were higher than the pre-extraction heights, while in women they were reduced below the pre-extraction heights. Race differences. 1. Both the occlusal and rest face heights were much greater among Negroids than among Caucasoids. 2. By the end of the 12 month postinsertion period, both occlusal and rest face heights in Negroids were higher than the pre-extraction heights, while in Caucasoids they were reduced below the pre-extraction heights. 3. During the first 6 month postinsertion period, both occlusal and rest face heights gradually decreased among Negroids and Caucasoids. However, during the second six months, they continued to decrease among Caucasoids and remained constant among Negroids. 4. During the 12 month postinsertion period, the rate of reduction of both occlusal and rest face heights was slower among Negroids than among Caucasoids. Age differences. 1. Both occlusal and rest face heights were much greater in the older age group than in the young age group. 2. By the end of the 12 month postinsertion period, both occlusal and rest face heights remained higher than the pre-extraction heights in the older age group, while in the young age group, they were reduced below the pre-extraction heights. 3. During the 6 month postinsertion period, both the occlusal and rest face heights gradually decreased in both age groups. But, during the second six months, they continued to decrease in the young age group and remained constant in the older age group. 4. During the 12 month postinsertion period, the rate of reduction of both occlusal and rest face heights was slower in the older age group than in the young age group. Individual differences. 1. The individual subjects demonstrated a wide range of variation in the pattern of changes occurring in face heights during the different phases of this study. 2. In one subject, both occlusal and rest face heights increased 5 mm. after insertion, decreased 2 mm. during the first six months, decreased an additional 1 mm. during the second six months, and were 2 mm. above the pre-extraction heights by the end of the 12 month postinsertion period. 3. In another subject, the occlusal face height increased 2 mm. after insertion and decreased 6 mm. during the 12 month postinsertion period, ending 4 mm. below the pre-extraction height. While rest face height was increased to the same pre-extraction height, after insertion it decerased 5 mm. during the first six months and remained at this height after 12 months. It ended 5 mm. below the pre-extraction height.