Jaw angle reduction or reduction gonioplasty
The shape of the lower jaw angles has an influence on the appearance of your face. The more prominent or square the jaw angles are, the more they enhance masculine features. When the jaw angles are too prominent, however, the jaw can be disproportionately wide as compared to the rest of the face. This may create a square-shaped face and is the motivation for aesthetic jaw angle modification surgery, also known as a genioplasty. A decortication of the area is sometimes performed as well, where some of the outer layer of the jawbone is shaved away. Sometimes, we remove the inner part of the masseter muscle or we use Botox injections (50 i.e.) to enhance the involution of the muscle in conjunction with the bone removal.
Jaw angle reconstruction or building of jaw angle
The preparatory phase for those patients is extensive. Indications are mostly infection and trauma, and Dr Defrancq regards 3D rendering and stereolithographic models as essential. We start to build the gonial angle in wax directly on a stereolithographic model (plastic copy of your own jaw) rendered in 3D. The final material is then PEEP or orthopaedic resin (palacos).
On the plastic replica of the jaw (stereolithographic model), the gonial angle is created first in yellow beeswax by the surgeon (1). This is then turned into resin (2) in the laboratory. A negative of those gonial angles is then made in jelly silicone and sterilised (3). During surgery, those sterile silicone housings are injected with regular orthopaedic resin (4).
Frequently asked questions
- Is silicone a reasonable alternative?
Silicone implants are rather soft and the difficulty here is the proper fixation in the proper location and keeping the implant there over time. This makes this kind of implant more unpredictable.
- Are there possible aesthetic complications?
Muscle disruption is possible if the muscle sling around the inferior border of the mandible (the pterygoid-masseteric sling) gets breached and rides up since there is no longer adherence to the bone. The muscle can then form a ball above the implant when the patient chews.
- When is orthopaedic resin indicated and when is a Peek (poly-ethylene-ethylene-ketone) implant indicated?
It is a matter of cost, complexity, and surgeon preference. Orthopaedic resin is more artisanal and work-intensive for the surgeon, but finally works out at half the price of the Peek. The Peek implant is made in a factory and is guided totally by computer. For a surgeon it is easier to be guided by a stereolithographic model, since it is a plastic copy of your own jaw with the same touch and feel, and to use this as a direct work model. Peek is about computers and 3D rendering, and images going backwards and forwards to the company until the correct model is delivered.