Pterygoid Implants: The Other Graftless Option

Behind your upper back teeth, where the jaw curves away and upwards towards the base of the skull, there is a junction of three bones. A pterygoid implant is placed through that junction: it enters at the very back of the upper jaw, passes through a small bony process of the palate, and finishes by engaging the pterygoid plates of the sphenoid bone — the bone that forms part of the skull base.

The name comes from those plates. It is nothing to do with the teeth themselves, and there is no equivalent site in the lower jaw, which is why pterygoid implants are an upper-arch option only.

What makes the region interesting is the quality of the bone rather than the quantity. This junction acts as a structural buttress that carries chewing forces up into the skull, so it is largely dense cortical bone — and, like the cheekbone, it does not shrink away after teeth are lost, because its job was never to hold teeth in the first place. That combination of density and stability is why an implant can find a firm grip there when the ridge in front of it has almost nothing left.

Because a pterygoid implant is angled steeply forwards and upwards from a point far back in the mouth, it is longer than a conventional implant and is planned in three dimensions from a CBCT scan rather than freehand.

The back of the upper jaw is the hardest place in the mouth to place an implant. Once upper molars are lost, the maxillary sinus above them tends to expand downwards into the space, a process called pneumatisation. What is left between the sinus floor and the gum can be a few millimetres of thin bone — not enough to hold a standard implant.

The established solution is a sinus lift: the sinus membrane is carefully raised and grafting material is placed underneath it to create bone height, and implants are placed once that has matured. It is a well-evidenced procedure with decades of use behind it and it remains the right answer for a great many patients, particularly when only one or two teeth need replacing. Its trade-off is time and staging — a healing period before implants can be placed, and in some cases a second surgical visit.

A pterygoid implant takes a different route to the same goal. Rather than building bone under the sinus, it goes around and behind it, anchoring in the buttress at the back. The sinus is not grafted and, in a well-planned case, not entered. That removes the graft healing period from the sequence for that part of the arch.

The clinical value is not simply avoiding a graft, though. A full-arch bridge needs support at the back, and if the rearmost implant sits too far forward, the bridge has to extend beyond it without support underneath. Unsupported extensions like that concentrate load on the implants in front of them. A pterygoid implant provides a genuine rear anchor point, which is often the real reason it is included in a plan.

If pterygoid implants can avoid a sinus lift, an obvious question follows: why has almost nobody heard of them, and why does hardly any clinic offer them?

Part of the answer is anatomical. The site is at the back of the mouth, the working angle is awkward, the important structures nearby are vascular, and the surgeon cannot see the far end of the drill path directly. That combination demands confident three-dimensional interpretation of a CBCT scan and a level of anatomical familiarity that sits closer to maxillofacial surgery than to routine implant dentistry.

Part of it is volume. Most implant practices see relatively few patients for whom this is the right answer, and a technique that is difficult and infrequently needed is one most clinicians reasonably choose not to adopt. Skills like this concentrate in a small number of centres rather than spreading evenly, in the UK and everywhere else.

Part of it is evidence. The literature on pterygoid implants is real but modest compared with standard or zygomatic implants, with fewer patients, fewer long follow-ups and variation in how the technique is described between groups. Reported outcomes have generally been favourable, but a cautious profession is slow to adopt a demanding technique on a modest evidence base, and that caution is not unreasonable.

The practical consequence for a patient is straightforward. If a pterygoid implant is proposed, ask how many the surgeon places each year, ask to see the planned trajectory on your own CBCT scan, and ask what the alternative plan would be — a sinus lift, or a different implant configuration — so you can compare like with like. If a pterygoid implant is not proposed and you have been wondering about it, that may simply mean the team does not place them; a second opinion at a centre that does is a legitimate step.