Table of Contents
Introduction
In the region of the atrophic posterior maxilla or the upper arch, where edentulous patients (with teeth missing or absent in this area of premolars and molars), there is a very high chance of dental implant failure in cases where there is severe bone resorption. Though conventional dental implantation is possible in dental implant cases who are suitable with good bone and without any interference from sinus issues, it is not always the case, especially in geriatric patients, patients with sinus diseases or sinus issues, patients with less bone or space in the posterior maxillary segment.
Hence because the chances of biological or prosthetic failure in these regions ie of the atrophic posterior maxilla would be higher and also because the bone density is lesser in this region, the dental implantologist is faced with several challenges or has to deal with real-time complications that would be possibly encountered during dental implantation.
What Are the Differences Between Zygomatic and Trans Sinus Implants?
Minimally invasive procedures that can also restore the functional efficiency of dental implants need to be considered by the implant dentist or the maxillofacial surgeon.
This brings us to the comparison between two major types of procedures that is the dental implants placed through the trans alveolar maxillary sinus floor-called commonly as trans sinus implants versus the zygomatic implants that are placed into the zygoma or the cheekbone of the face, instead of implanting in the upper jaw or the maxillary region.
Zygomatic implants are usually done when the patients do not require a sinus augmentation or where sinus augmentation would possibly fail. They are the alternatives to trans sinus implants that are placed through the floor of the maxillary sinus.
On the other hand, in patients who cannot undergo bone augmentation procedures, trans sinus implants can be easily performed by the implant dentist.
In trans sinus implants, the dental implants are inserted without any sinus grafting and are fixated into the nasal cortical bone. These implants are usually angled forward and have an immediate loading protocol with success rates postoperatively even up to three years, post-dental implantation according to current dental implant research.
Zygomatic implants are considered a more viable option when the dental operator has no other alternative to rehabilitate the patient's functional, speech, and masticatory, especially in severely resorbed bone as seen in aged patients. Because in geriatric patients, continuous bone resorption would be the common cause eventually leading up to a loss of the structural integrity of the jaw bone and causing continued resorption of the maxillary alveolar process-dental implants in the posterior maxilla region would indeed be a challenging task or to see the success light post-operatively, in terms of dentally rehabilitating these cases.
In several challenging maxillofacial surgical procedures, zygomatic implants are often placed as an adjunct by the dental operator to compensate for the loss of natural teeth and their functions as in the complicated cases of Le Fort fractures of the jaw, in surgical procedures of the maxillary antrum or the nasal floor, in bone grafting that is interposition or in onlay grafting procedures.
What Factors Influence the Clinical Decision Regarding the Selection of an Implant Type?
The clinical decisions where full-fledged dental rehabilitation would be required in such cases of extensive bone resorption and with complex situations would hence be handled by the implant dentist through a thorough pre-operative assessment of the patient. Further, the dentist needs to keep in mind the patient's financial, esthetic, and functional expectations and accordingly give their opinion regarding the possibility of an implant prosthesis.
Usually, dental surgeons will not recommend trans sinus implants in the following patients:
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Patients diagnosed with a history of sinusitis or any paranasal sinus infections in the presence of any systemic infections, or uncontrolled diabetes.
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Patients taking chemotherapeutic medications or Aminobisphosphonate drugs.
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Patients planning or indicated for/to undergo any bone augmentation procedures.
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Patients with good or adequate sufficient bone height in the posterior maxillary region.
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Patients with psychiatric issues.
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Patients suffering from depression, insomnia, anxiety, or mental health issues.
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Patients suffering from emotional instability.
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Substance abusers or drug abusers.
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Chronic alcoholism and smokers.
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Patients who may be undergoing radiation therapy to the maxillary region.
In all the above-enlisted situations that are not good clinical scenarios for trans sinus implants, the dental operator can take a call either to opt for zygomatic implants or in rare cases, conventional endosteal implants.
After a detailed and rather thorough pre-operative assessment by the implant dentist in these cases of atrophic posterior maxillary regions, the dentist would then decide whether to opt for a conventional endosteal dental provided that the patient has sufficient bone volume as well as height or to opt for a trans sinus implant that is the most viable alternative to facilitate functional success or in the last option opt for zygomatic implants in patients who are highly complex cases (such as patients afflicted with cancers, who require osseous or jaw resection surgeries, and patients with failed sinus augmentation procedures).
The clinical decisions would be hence accordingly made either in an interdisciplinary collaboration with the maxillofacial surgeon and the implantologist or keeping in mind the patient's esthetic and functional expectations.
Conclusion
It is important to note that the posterior atrophic maxilla can present challenging clinical situations that need to be addressed by the implant dentist. With the advent of computer-assisted planning on virtual platforms in implant dentistry, by the use of 3D guided surgical templates, CBCT 3D imaging (cone beam computed tomography) and even prefabricated surgical splints or templates-the dental operator should cautiously and effectively plan the dental implant pre operatively itself.
Preoperative planning can help the dentist to correctly position the implants and also meet the functional expectations of the patient to be rehabilitated. Further post-operative success rates matter the most, for which the decision of zygomatic versus trans sinus implants should be considered carefully by the dental surgeon/implantologist.
