There is an established association of bone changes with facial implants but it is poorly understand despite that the biology of bone remodeling in response to mechanical stress is well known.
Facial implants can cause underlying bone resorption (bone remodeling/erosion), although the degree varies considerably by implant type, location, design, fixation method, and duration of implantation.
What happens?
Bone is a living tissue that responds to pressure. When an implant rests against bone for years, that pressure can lead to:
- Cortical thinning
- Shallow saucerization or indentation of the bone (imprinting)
- Localized bone resorption/remodeling
In most cases this is a slow, self-limited remodeling phenomenon rather than aggressive bone destruction. Interestingly it is not a uniform phenomenon. In some patiensts you see while in others it i not seen at all.
By implant type
Chin implants
- Bone resorption beneath silicone chin implants is well documented.
- Usually occurs across the how implant interface
- Most cases are minor and asymptomatic
- May be more visible in:
- Large implants
- Implant mobility
Jaw angle implants
- Can produce pressure remodeling of the mandibular angle.
- Clinically significant bone loss is uncommon but radiographic remodeling is not rare.
Malar/cheek implants
- Typically cause very little bone imprinting than chin implants.
- Mild remodeling beneath the implant may be seen on CT scans years later.
Paranasal implants
- Generally show minimal bone change, have never seen any actual evidence of it
Does implant material matter?
- Silicone implants have the longest history of reported pressure-related bone resorption.
- Porous polyethylene (Medpor) implants integrate with tissue and may distribute forces differently, but bone remodeling can still occur.
- PEEK and titanium can also induce remodeling if they create chronic pressure.
The issue is more related to mechanical loading and implant stability than simply the material itself.
Is it clinically important?
Most of the time:
- The bone changes are discovered incidentally on imaging.
- They do not affect aesthetics or implant stability.
- No treatment is required.
Occasionally, significant resorption can:
- Complicate revision surgery as bone overgrowth need to be removed
How much bone loss?
Published studies of long-term chin implants have shown everything from:
- Minimal cortical remodeling
- To several millimeters of localized bone resorption in some patients after many years
Severe resorption is very uncommon and it typically associayted with highly positioned chin implants where the cortical bone is thinner
Bone Overgrowth
Practical perspective
For most facial implant patients, some degree of underlying bone remodeling over decades should be considered a normal biological response. The area of greatest concern is silicone chin implants, where bone resorption is most consistently reported and can occasionally become significant enough to influence management or revision planning.
Dr. Barry Eppley
Plastic Surgeon