I would probably go through the original incision and revise it so it looks better. Through this incision I would get a better look at any scar or bone erosion.
How will an old chin implant be replaced?
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 order to place the chin implant through the mouth, the attachment of the Mentalis muscle to the chin bone must be cut. This allows the implant to shift upwards as well as increasing the chance of chin muscle droop (chin ptosis). For this reason, I don't place chin implants through the mouth.
Hope this helps.
Your new chin implant can be replaced either from inside the mouth or from under the chin. You may take the opportunity to revise the scar under the chin for the replacement to address both the implant and scar concerns.
Firstly, you said that the scar under the chin doesn't look very good. There is a risk that the scar wont get better, after scar revision, or may get worse if you put more tension on the tissues, with a larger implant.
If you can live with the present scar, I would use an intraoral approach to insert a new, modern implant.
I suggest you excise the old scar, remove the old implant, enlarge the pocket, and the insert the new implant. This approach will give you the opportunity to do a scar revision as part of the procedure..
Removal and replacement of a chin implant
Since there is an incision underneath the chin already, its best to cut the old scar out and remove and replace the chin implant through that incision. The old implant can be removed, the pocket made larger to accommodate the implant with wings, and the new implant is inserted and the incision closed. This can be performed under local anesthesia as an outpatient surgical procedure. For many examples and more information, please see the link and the video below