Understanding the Complex Process of Facial Bone Remodeling
The human face is a complex structure that undergoes continuous, dynamic changes throughout life, a process known as bone remodeling. This biological activity involves a delicate balance between bone-resorbing cells (osteoclasts) and bone-forming cells (osteoblasts). While bone growth is a dominant force during childhood and adolescence, the adult skeleton undergoes constant turnover, replacing old bone with new. However, as we age, this balance shifts, with resorption gradually outpacing formation, leading to a net loss of bone volume and density in specific areas.
This remodeling is not uniform across the facial skeleton. Instead, certain areas are more susceptible to change, particularly those supporting soft tissues. In the mandible, or jawbone, significant remodeling occurs, and advanced imaging has provided new insights into these predictable patterns of change.
The Surprising Truth About Ramus Height
Contrary to early assumptions that the mandible expands continuously throughout life, recent research offers a different perspective on how mandibular morphology changes with age. Several comprehensive studies have used 3D imaging and cephalometric analyses to observe these long-term trends.
A significant finding is that the vertical dimension of the mandible, including the height of the ramus, decreases over time. For example, one 2025 study analyzing computed tomography scans of individuals aged 20 to 79 found that ramus height showed a significant decrease with age, by approximately 5.3 mm in women and 4.2 mm in men. This bone resorption in the posterior aspect of the jaw is a key contributor to visible facial aging, resulting in a less pronounced jawline and contributing to the formation of jowls.
How Other Mandibular Features Change with Age
The mandible’s changes are multi-dimensional, affecting more than just ramus height. As bone resorbs, other measurable parameters of the jaw also shift, altering the overall facial silhouette. The gonial angle, or the angle of the jaw at its posterior border, tends to increase with age. This widening of the jaw angle further contributes to a less defined and more rounded lower face. Simultaneously, studies have shown that interrami width—the distance between the two rami—can increase, creating a broader, more squared-off appearance in the lower face.
The Role of Bone Resorption and Gender
It is now clear that mandibular aging involves specific bone remodeling patterns that differ between the sexes. For instance, women often experience more rapid and earlier onset of certain age-related bone changes, potentially linked to hormonal factors like menopause. The bone loss process in women is often more intense and begins earlier compared to men, who might see more pronounced changes at a later stage. Additionally, the location of resorption can differ, with women sometimes showing more bone loss at the chin (symphyseal) region and men exhibiting more concentrated loss at the gonion.
Impact of Tooth Loss and Masticatory Forces
While natural aging drives predictable bone remodeling, certain external factors can significantly accelerate the process. The presence or absence of teeth, in particular, plays a critical role. The mechanical stimulation from chewing and biting helps to maintain the health and density of the jawbone. When teeth are lost, the alveolar bone—the bone that supports the teeth—is no longer stimulated, which triggers a much faster and more severe bone resorption process.
For individuals with tooth loss or those who wear dentures, the reduction in biomechanical forces leads to a marked decrease in mandibular height and width, including the ramus. This can cause a shrunken facial appearance, premature wrinkles, and a compressed look in the lower face.
Comparison of Age-Related Mandibular Changes
| Mandibular Feature | Change with Age (Post-Adolescence) | Primary Mechanism | Impact on Facial Aesthetics |
|---|---|---|---|
| Ramus Height | Decreases | Bone resorption, shifting remodeling balance | Diminished jawline definition, softer contour |
| Gonial Angle | Increases (widens) | Bone resorption at the angle | Less defined jaw angle, rounder lower face |
| Interrami Width | Increases | Bone remodeling, differential resorption patterns | Broader, more square-shaped lower face |
| Mandibular Body Height | Decreases | Bone resorption, especially accelerated by tooth loss | Shortened facial height, sunken appearance |
| Prejowl Area | Resorbs | Selective bone resorption | Formation of jowls |
Conclusion: Adapting to the Reality of Facial Aging
The answer to the question, does ramus length increase with age, is a definitive no. The prevailing scientific evidence shows that ramus height decreases as part of a broader, age-related process of skeletal remodeling. This predictable bone loss, which affects the mandible in specific ways, contributes significantly to the characteristic signs of facial aging. Understanding these underlying bony changes is crucial, not only for individuals seeking to comprehend the physical effects of aging but also for medical and dental professionals offering corrective and restorative procedures. By addressing the skeletal framework, it is possible to achieve more natural and effective results in facial rejuvenation.
For a deeper dive into how the facial skeleton changes with age, explore this comprehensive article by the National Institutes of Health: Changes in the Facial Skeleton With Aging.
