Why do silicone chin implants cause bone erosion?

 Hi, I have performed many Chin Augmentations using chin implants for over 30 years.  A weak chin creates an imbalance making the nose appear larger, the mid face top heavy and the lower face look short that de-emphasizes the lips and allows early formation of a double chin.  Chin augmentation using a chin implant will add projection to the chin creating harmony and balance to the lower face. 

 I have found that placement of a silastic chin implant, through a small curved incision under the chin (also allows excess skin removal) to be very safe, quick, highly effective and far less invasive than a sliding genioplasty.  I perform chin implant surgery in 30 minutes or less, often using a local anesthetic alone. 

 In my opinion, any small amount of bone erosion, when it occurs is due to movement of the overlying Mentalis Muscle.   This will "not" be decreased with placement of screws through the implant.  I have replaced numerous cheek and chin silastic implants that were placed elsewhere and had screws to secure the implant.  In many cases the screws were completely through the implant but attached to the underlying bone.  If you think about that, it makes sense.  Take a soft object (a silastic implant is soft, solid silicone) and try attaching it to a hard surface (bone) using a hard screw...the screw will dig into and eventually go through the soft implant.  The implant is placed below the periosteum (covering on the bone) which quickly adheres back to the bone securing the implant and IMHO, no sutures or screws are required to stabilize the implants.  It is however, paramount to develop a proper sized implant pocket and close all tissue layers along with use of a U-shaped pillow for 1 month post op. 

Hope this helps.

The bone 'erosion' is due to the overlying mentalis muscle 'pressing' the implant against the bone. The mentalis muscle raises the lower lip and closes the lips together; so it is always functioning and pressure can result. This is unusual, for example, in the cheekbone area or jawline area/angle of jaw. The amount of 'erosion' can depend upon the patient's growth structure since some patients cannot close their mouths naturally; and have thinner bone below the incisors. Talk to a Maxillofacial surgeon about it.