During the past few decades, the technological advances and innovative developments in health and medicine have far surpassed those of previous generations. The same thing can easily be said about dentistry and oral care. Despite these developments, one study showed that the prevalence of complete edentulism among US adults is approximately 13.5%, which means that about 40 million adults in the United States suffer from this condition.¹

The all-on-X dental implant procedure is an excellent treatment option for patients with complete edentulism. In the all-on-X dental implant procedure, a full arch of teeth is restored by placing four or more dental implants that are used to support a full-arch prosthesis. This offers the advantage of a quicker restoration process, among other benefits. However, as with many beneficial healthcare solutions, there are also complications that can occur. As dental providers become more aware of the complications that can arise with all-on-X procedures, it is critical for them to take precautionary measures to prevent or mitigate them.

When dissecting the common complications or failures related to performing all-on-X implant procedures, it is vital to understand both the short-term and long-term effects.² Although some complications could be experienced shortly after surgery, others are not distinctly noticeable until long after the patient has functioned with the prosthesis.

Immediate Postoperative Complications

Immediate postoperative complications can involve integration of the implants, infection, functional and esthetic issues, and problems associated with the design of the interim prosthesis. Some of the most widespread include the following:

Fibro-osseous Integration

In cases of immediate loading, reasons for fibro-osseous integration, or failure to integrate with the bone, include that the interim prosthesis does not passively fit or that the occlusion is incorrect. This can be avoided by ensuring that the interim prosthesis is fabricated using the most accurate tools available, such as photogrammetry or an intraoral scan with scan bodies designed for full-arch cases, and with a strong fracture-resistant material. In addition, it is crucial that passive seating be confirmed by radiography.

Infection

Implant sites can become infected after surgery as a result of improper sterilization techniques, not following the manufacturer's recommended implant drilling protocol, or failure to treat a previously existing infection at the surgical site, among other factors. Following proper surgical and sterilization techniques and providing antibiotic coverage in cases of existing infections is vital to avoid immediate postoperative infections.

Altered Speech

Depending on the extent of the implant procedure, patients often experience altered speech due to the thicker feel of the teeth and/or gums. This temporary complication usually resolves on its own after an adjustment period. In rare instances when it does not, speech therapists can help.

Esthetic Complications

In patients with high smile lines, if the bone is not sufficiently reduced, the transition line between the prosthesis and the gingiva may be visible, making the result an esthetic disaster. It's important to properly evaluate and plan each case before the surgery to prevent this complication from occurring.

Fracture of the Interim Prosthesis

In cases in which the implants are immediately loaded, the interim prosthesis can fracture if the patient is not compliant with postoperative instructions, including following the necessary diet. Other issues that can result in fracture include the development of improper occlusion, bruxism, or a cantilever in the posterior or anterior region. Fracture can be avoided by fabricating interim prostheses with stronger materials, such as 3D printing resins, and reinforcing with metal wire. The occlusal scheme should be bilaterally balanced with minimal occlusal anatomy to provide the patient with freedom of jaw movement. Fabricating interim prostheses with shorter lengths can help avoid the need for a cantilever.

Short-Term Complications

Short-term complications often occur after delivery of the final prosthesis. These can include the following:

Screw Loosening/Screw Fracture

In one study that evaluated 56 participants who underwent all-on-X procedures, 43% experienced abutment screw loosening and 21% experienced another form of loosening.³ Although screw loosening is a minor mechanical complication, it is common. As such, it's critical to ensure that all screws are adequately tightened or torqued during procedures and that they are checked with consistent postoperative follow-ups. If loosened screws go unchecked, it can lead to screw fracture.

Chipping or Fracture of the Prosthesis

In that same study, 25% of the participants experienced chipping of the veneering material or fracture of the final prosthesis. A common issue in all-on-X cases is broken bridge material. Fractures often occur due to bite problems or insufficient thickness from the gingiva to the occlusal plane. This can be avoided by ensuring that prostheses are created with accurate dimensions. Full-arch prostheses should be fabricated from a durable material, such as zirconia, and designed to be convex and easy to clean while maintaining the minimum material thickness to prevent fracture.

Long-Term Complications

Common long-term complications can be either biologic or prosthetic. Some of these include the following:

Bone Loss/Gum Recession

When the metal or abutment material is exposed, it may show superior cleanliness. The presence of thin soft tissue or bone often results in implant exposure, but a connective tissue graft can slow or halt the recession. Patients with thicker gums usually avoid this problem altogether. In a 2019 study, 19 edentulous patients who were restored with both maxillary and mandibular full-arch implant-supported prostheses received follow-ups after a mean observation period of 5 years.⁴ Roughly 45.5% of these patients experienced soft-tissue recession.

Peri-implant Mucositis/Peri-implantitis

If oral hygiene is not maintained at home, plaque and calculus can accumulate around the implant and the prosthesis. This can lead to peri-implant mucositis, which can progress to peri-implantitis. Like teeth, implants require maintenance. Regular check-ups can help reduce the risk of peri-implant disease. It's also important for patients to maintain a healthy daily oral hygiene regime and avoid smoking and vaping.

Wearing of Acrylic Teeth

If the prosthesis is made of acrylic with a titanium bar, the acrylic teeth will likely wear over a period of time. The best solution is to avoid the risk of this happening altogether by fabricating full-arch implant-supported prostheses from wear-resistant materials, such as zirconia.

Recent Developments and the Future of All-on-X Treatment

With technological advancements and the growth of artificial intelligence (AI), digitally based solutions are the forefront of implant procedures. Gone are the days of traditional dentistry reliant on analog radiography and fully manual procedures. The use of cone-beam computed tomography (CBCT) scans and digital planning have enhanced the treatment process.⁵ These tools allow doctors to better understand patients' unique needs so that they can provide the best implant solutions. For example, digital imaging provides more detailed images of patients' mouths, which enables doctors to place implants more accurately and with the proper angulation. Using a digital scan of the mouth to create a 3D model also facilitates the design of prostheses that fit patients perfectly.

Another development in the field of prosthetic dentistry is the evolution of implants and their components to facilitate immediate loading protocols, which has enabled patients to receive their prostheses on the same day as the implant surgery. This protocol dramatically reduces the waiting time for patients and improves efficiency for doctors by reducing the total number of appointments required. In addition, the advent of 3D printing has enabled the fabrication of stronger and more accurate interim prostheses, and the use of robotics to guide implant placement is increasing the accuracy and predictability of all-on-X procedures.⁵

Dental care is evolving toward all-in-one practices that offer comprehensive care in one location and reduce interactions with outside specialists.⁵ In this model, patients experience the benefits of convenient and cohesive care. This can improve patient satisfaction and boost practice loyalty and retention. By incorporating implant services, such as all-on-X treatment, practices can remain competitive and cost-efficient in this landscape.

Refining Procedures for Better Outcomes

As the protocols for all-on-X procedures evolve, doctors and providers should take preventive measures and apply the most appropriate techniques to reduce the number of complications experienced by patients. By focusing on the sources of these problems, dentists can help to refine implant procedures to ensure better outcomes, enhancing care for future patients-patients who will have even greater peace of mind that their treatments will deliver the desired results.

Aditya Bhawsar, BDS, MDS
Associate Fellow American Academy of Implant Dentistry
Lifetime Dental & Implant Center Katy, Texas A Dental Care Houston, Texas