Vertical Lengthening Jaw Angle Implants

Q: Dr. Eppley, I have a question about jaw angle implants. I recently saw a question on your blog regarding the inevitability of massteric pterygoid sling disruption when there is vertical lengthening of the jaw angle and was wondering if you could elaborate a bit further on the aesthetic impact of this disruption (specifically, the masseter muscle “roll up” that can occur). Does this mean when the jaw is in a normal position, the bulge of the masseter is going to visibly rest higher than the very bottom of the jaw angle? With lengthening of 10-12 mm, is this effect very significant? I was hoping you may have some sort of visual representation of this effect so that it can be more clearly understood – it seems to be a potential negative drawback of too much vertical lengthening.

A: By definition any vertical jaw angle implant lengthening causes some disruption of the masseteric-pterygoid muscle union along the bottom edge of the jawline over the mandibular ramus area. This is inevitable and a consequence of the procedure. But this does not mean that it is always an aesthetic problem. I have done many vertical lengthening jaw angle implants and custom jawline implants (some as long as 25mms), I would say it was only a bothersome aesthetic consequence in less than 10% of the patients.

Disruption of the masseteric pterygoid sling can cause two aesthetic (no functional) problems. When biting down, the bulge of the massteric muscle can be seen to be higher than the actual skeletal/implant jaw angle location. Or they can be persistent fullness above the jaw angle that prevents a well defined jaw angle definition (or flare of the jaw angle) to be seen. There is no way to predict beforehand what type of vertical lengthening jaw angle implant patient this aesthetic sequelae may be seen in.

Dr. Barry Eppley

Indianapolis, Indiana