Chin implant

What it is

• The implant sits on the front of the jawbone, usually under the bone lining (periosteum), and adds projection and width to the chin (PMID 36880789).
• The jawbone itself shrinks with age: its height and length fall and the jaw angle widens, in men and women (PMID 20048624). A facelift lifts the soft tissue but cannot restore lost bone (PMID 15988655).
• The hollow in front of the jowl (prejowl sulcus) comes from bone loss, fat loss and loose ligaments, and a facelift alone rarely fills it (PMID 27680523). Extended "prejowl" implants fill that hollow and smooth the jawline (PMID 18063249).

Where it came from

• By 1969 surgeons had reported that plastic chin implants can sink into the bone beneath them (PMID 5249632).
• In 1984 a chin implant was paired with liposuction under the chin to sharpen the angle between chin and neck (PMID 6732587).
• In 1991 surgeons showed that removing an implant can leave the chin sagging, and in 1996 that lips which strain to close mark the chins most at risk of erosion (PMID 2052662, PMID 8911470).
• Fixing the implant with small screws and placing it on the lower edge of the jaw followed in the 2000s (PMID 14504528, PMID 17898616). Custom implants made for one patient are now used for revisions and complex shapes (PMID 40225117, PMID 41753014).

Who it suits

• A mild to moderately small chin; a severely small chin, a bad bite or a long lower face needs bone surgery (a sliding genioplasty) instead (PMID 36729121).
• Facelift and neck lift patients with a weak chin or jawline, where the implant strengthens the profile (PMID 28571065, PMID 15988655).
• People with a short neck, where treating the small chin improves the neck lift result (PMID 36563674).
• People who want to avoid bone surgery: implants cause less lip numbness than genioplasty but more infection, and the soft tissue follows about two thirds of the implant's projection against more with bone surgery (PMID 36729154, PMID 40666078).

How it is done

• The surgeon makes a short cut under the chin or inside the lower lip and creates a pocket on the bone (PMID 36880789, PMID 22241784).
• The nerve that gives feeling to the lower lip leaves the bone about 1.5 cm above the lower edge of the jaw, and the safe zone for an implant lies below it (PMID 23542258).
• A pocket fully under the bone lining had fewer shifts, revisions and removals than a dual-plane pocket (PMID 36880789).
• Some surgeons fix the implant with screws; complications occurred with and without fixation (PMID 14504528, PMID 36874350).
• The operation is short and often done under local anesthesia (PMID 36729121, PMID 17898616).

Results and how long they last

• Chin projection and the lip-chin angle improved at 12 months after ePTFE implants, and satisfaction scores rose (PMID 42682026). Nearly all patients in a porous polyethylene series were highly satisfied with chin shape (PMID 36917098).
• Systematic reviews describe durable projection and high satisfaction, with evidence mostly from retrospective studies (PMID 41714371).
• Porous polyethylene chins felt firm and bone-like up to 15 years later, and few needed trimming (PMID 22684610). ePTFE implants showed no resorption or movement in a large series (PMID 12756115).

Risks and how surgeons lower them

• Any complication followed about 1 in 6 implants in pooled studies, against about 1 in 5 bone procedures; temporary lip numbness followed about 1 in 40 implants against about 1 in 6 genioplasties (PMID 36729154).
• Shifting: implants in a pocket fully under the bone lining shifted and needed revision several times less often than implants in a dual-plane pocket (PMID 36880789).
• Numbness by material: rare with silicone, about 1 in 5 with porous polyethylene, about 1 in 30 with ePTFE (PMID 36880789).
• Infection: about 1 in 160 ePTFE implants and about 1 in 110 porous polyethylene implants were infected (PMID 12756115, PMID 36917098). Infections reported to the FDA appeared months after surgery, and most of those implants were removed (PMID 29346485).
• Bone erosion under the implant is common but usually under 2 mm, and it deepens with time (PMID 35402503, PMID 11994120). It was more likely with silicone, a thick or strong chin muscle and thin bone (PMID 39271547, PMID 8911470). New bone growth around silicone implants is also reported (PMID 39925480).
• Removal: after an implant is taken out the chin can sag and bunch; the authors advise bone surgery at the time of removal (PMID 2052662). Revisions use genioplasty, jaw surgery or a custom implant (PMID 41753014).

Recovery

• Swelling, temporary lower lip numbness and mild asymmetry after implant placement settled without treatment (PMID 42682026).
• Irritation of the stitch line inside the mouth was uncommon and resolved (PMID 22241784). Wounds under the chin opened less often than wounds inside the mouth (PMID 37059630).

With a facelift

• Chin and cheek implants placed during a facelift did not raise hematoma, infection, nerve injury or scarring compared with facelift alone (PMID 20392030).
• Chin and prejowl implants are used with facelift to rebuild the aging jawline (PMID 15988655, PMID 18063249).
• A sagging "witch's" chin is treated by removing the extra tissue, with a stable implant when more projection is needed (PMID 1631213).

Questions to ask a surgeon

• Is an implant or a sliding genioplasty better for my chin? (PMID 40666078)
• Which material, and will the pocket be under the bone lining? (PMID 36880789)
• How often do your chin implants become infected or shift? (PMID 29346485)
• What happens to my chin bone over the years? (PMID 35402503)
• If I ever want it out, what will my chin look like? (PMID 2052662)

Open questions

• How much bone erosion matters: common but mostly under 2 mm (PMID 35402503), with new bone formation also reported (PMID 39925480) and risk factors seen on CT (PMID 39271547).
• Implant or bone surgery: fewer nerve problems with implants, more infection (PMID 40666078, PMID 37059630).
• Screw fixation or a snug pocket (PMID 36874350).
• Short follow-up across the implant literature (PMID 29994843, PMID 41714371).

Terms

• Microgenia: an underdeveloped, small chin (PMID 36729121).
• Alloplastic implant: a synthetic implant, not taken from the patient (PMID 36880789).
• HDPE / Medpor: porous polyethylene that tissue grows into (PMID 22684610).
• ePTFE / Gore-Tex: expanded polytetrafluoroethylene implant material (PMID 12756115).
• Subperiosteal pocket: a space under the bone lining in which the implant sits (PMID 36880789).
• Bone erosion / resorption: loss of chin bone under the implant (PMID 35402503).
• Mentalis: the chin muscle (PMID 23542258).
• Mental foramen / mental nerve: the opening and nerve that give feeling to the lower lip and chin (PMID 23542258).
• Prejowl sulcus: the hollow in front of the jowl along the jawline (PMID 27680523).
• Labial incompetence: lips that do not close at rest without strain (PMID 8911470).

Papers