Bone Density May Affect Rejuvenation Efforts

BOSTON - The density of facial bone seems to decrease significantly with age, a finding that suggests that the maxilla and mandible are subject to the same metabolic factors that cause osteoporosis in the axial skeleton, according to Dr. Robert B. Shaw Jr.

In a study designed to quantify age-related changes to facial bone density and compare them with age-related bone density decreases in the axial skeleton, Dr. Shaw, of the University of Rochester (N.Y.) Medical Center and his colleagues obtained dual-emission x-ray absorptiometry (DXA) scans of the facial bones and lumbar spine from 30 female and 30 male patients. The study included 10 patients of each gender in each of three age categories: 20-40 years, 41-60 years, and older than 60 years. Patients with osteoporosis were excluded from the study.

For each subject, the investigators recorded maxillary bone density (mean density of the left and right maxilla), mandibular ramus bone density (mean density of the left and right mandibular ramus), and lumbar spine bone density (mean density of L1-L4 vertebrae), Dr. Shaw said at the annual meeting of the American Society for Aesthetic Plastic Surgery.

The investigators observed significant decreases with age for both genders between the middle- and old-age groups for lumbar spine density and between the young and middle-age groups for the maxillary and mandibular ramus bone density, Dr. Shaw reported.

Specifically, the respective mean lumbar spine densities for the young, middle-age, and older-age groups of men were 1.29, 1.29, and 1.15 g/cm², and for the women were 1.23, 1.24, and 1.08 g/cm². For the maxillary bone density, the respective measures across the age groups for the men were 1.90, 1.58, and 1.56 g/cm², and for the women they were 1.75, 1.55, and 1.50 g/cm². For the mandibular bone density, the respective measures for the male subjects were 1.52, 1.33, and 1.35 g/cm², and for the female subjects they were 1.52, 1.32, and 1.18 g/cm².

Within each age group, "lumbar spine and maxilla bone density decreases were more pronounced in female vs. male subjects," he said.

The study findings are consistent with those of an investigation published earlier this year in which Dr. Shaw and his colleagues compared three-dimensional reconstructions of CT scans of the facial bones in 120 men and women in young, middle-age, and older-age groups. The investigators observed recession of the eye socket bones and volume loss to midface bones, including the brow bone, nose, and upper jaw. The bone-loss patterns observed in the study differed by gender, with men experiencing the most pronounced decrease in bone volume beginning in the oldest age category, while the process starts in earnest for women in the middle age group, he said (Plast. Reconstr. Surg. 2011;127:374-83).

The results of the current study suggest that "facial bone aging may be linked to the same metabolic factors that cause osteoporosis in the axial skeleton," said Dr. Shaw. They also offer insight into why certain facial rejuvenation strategies may not meet patients' expectations, he said, noting, for example, that although skin tightening alone may effectively minimize wrinkles and improve skin texture, it won't compensate for the underlying structural changes that alter the three-dimensional contour of the face.

Skeletal augmentation via dermal fillers or facial implants, together with skin tightening, can potentially improve outcomes by making up for some of the lost volume, he said, "but it will not make a 60-year-old look 20 years old again." Gaining a better understanding of facial bone strength, however, may lead to new possibilities for facial rejuvenation, he said.

Dr. Shaw reported having no financial conflicts of interest with respect to his presentation.