Boota Ubhi explains the wonders of zygomatic implants and how they can change patient’s lives for good.
Some patients are unsuitable for conventional implant treatment in the edentulous maxilla. This is because they have insufficient bone to provide sound anchorage. This can be due to factors such as advanced bone resorption, atrophy of the alveolar ridge, or extensive maxillary sinuses.
For many patients, bone grafts provide the necessary foundation for placing implants. This doesn’t work for everyone.
The number of patients suffering from a fully edentulous maxilla today is lower than in the past. However, when the condition does manifest, even experienced clinicians can face serious challenges in successfully rehabilitating the patient.
Dental professionals often perceive autogenous bone grafts as the current gold standard. Although, they are not without drawbacks. This includes donor-site morbidity, unpredictable resorption and the potential lack of available volume.
Meanwhile, extraorally-sourced bone grafts have been associated with increased risks of morbidity and complications (Jensen et al, 2016).
Bone graft procedures generally afford a high rate of success. Now, an alternative exists for patients who are contraindicated for, or wish to avoid, bone grafting – zygomatic implants.
What is a zygomatic implant?
Zygomatic implants bypass the requirement to rebuild the necessary bone structure. They have been in use for around two decades now, with an impressive track record.
A systematic review of over two dozen studies reported a 100% success rate, with an implant survival rate of 98% after three years (Goiato et al, 2014).
Weaknesses in bone structures cause many implant failures. A five-year analysis reports that 35% of all implant failures occurred in the porous trabecular bone, due to its thin cortex. For the same reason, immature bone grafts increase failure rates (Kate et al, 2016).
Rather than using the comparatively delicate tissue found in the roof of the mouth, zygomatic implants utilise longer screws to access the zygoma. The zygoma provides a firm foundation, though typically you require four cortical portions due to the specific microarchitecture of the region rather than one or two as with conventional implants (Sharma and Rahul, 2013).
Since the procedure doesn’t require a graft, only a single surgical procedure under local anaesthetic is required, which may be desirable for certain patients.
Sinus bone graft contraindications
The main contraindications for sinus bone grafts are:
- Alcoholism
- Heavy smoking
- Acute or chronic maxillary sinusitis
- Recent radiotherapy in the maxilla
- An uncontrolled systemic disease such as diabetes mellitus
- Psychosis
- Oroantral fistula
- A tumour in the maxillary sinus (Kumar and Anand, 2015).
Previously, the presence of an antral pseudocyst was considered an absolute contraindication for a sinus lift procedure, with additional surgery recommended to remove the cyst prior to a sinus lift.
However, more recent reports suggest that even if pseudocysts are present, you still perform sinus lifts. Although, larger lesions increase the risk of complications.
A pseudocyst reduces the size of the maxillary antrum, which can lead to blockages and can provoke the development of sinusitis. It is also possible that a pseudocyst may leak into the grafted area, which can result in infection and cause the graft to fail (Delilbasi et al, 2014).
Previously-failed bone grafts may also make subsequent attempts more difficult or indicate an underlying problem.
Which patients benefit most from zygomatic implants?
The main beneficiaries of zygomatic implants are patients with: severe resorption of the maxilla, total edentulism (especially if coupled with reduced bone height) or pneumatisation of the maxillary sinus.
For edentate patients with extremely severe resorption of the anterior maxilla, you can combine this technique with a bone graft. The dimensions of the graft in this case can be smaller than would be required with the more common approach.
Due to the reduced treatment time and preoperative risk of zygomatic implant placement compared to traditional bone-grafting methods, it may be an option for older patients and those with significant general health problems (Sharma and Rahul, 2013).
Referring patients for the best outcomes
Zygomatic implants have several advantages over conventional graft-based procedures and for some patients, they are the optimal treatment modality.
If you feel that your patient may benefit from this treatment but are unable to offer it yourself, then you need to refer them to a practice you can trust.
Quality dental referrals help ensure the very best outcomes for patients and reflect well on your own practice.
For references, contact: [email protected].
This article first appeared in Implant Dentistry Today magazine. You can read the latest issue here.
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