Jaw Size, Body Weight, and Saliva Signals in Teens

A small study looked at 50 teenagers who were getting orthodontic care. Their average age was about 13.5 years. The group split into 26 with normal BMI and 24 with increased BMI. Researchers checked jaw length, skeletal maturity, and hormone levels in saliva.

They used side-view skull X-rays to measure the upper and lower jaw. They also used hand and wrist X-rays to track bone age. Saliva samples were tested for several markers, including growth hormone, IGF-1, cortisol, estradiol, testosterone, adiponectin, and resistin. The team compared the two BMI groups and adjusted for age, sex, and race.

Teens with higher BMI had longer lower jaws. The average difference was about 8.13 mm. The upper jaw showed a similar pattern, but it did not reach the same level of statistical support. Other jaw, dental, soft tissue, and maturity measures did not differ clearly between the groups.

Saliva markers also stood out. The higher BMI group had lower cortisol and higher resistin. In the adjusted models, adiponectin in saliva was linked to shorter upper and lower jaw lengths. The study was registered under ClinicalTrials.gov identifier NCT07217756.