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Immediate Implant Full-Arch Loading: Case Selection and Technique
Three case examples utilizing the All-on-4 treatment protocol
Olga Malkin, DMD, FICOI
For most patients, losing teeth is emotional. In the past, the only treatment option for patients who were about to lose all their remaining natural teeth was to provide them with an immediate denture followed by implant placement after 6 months of bone and soft tissue healing. This lengthy and uncomfortable protocol discouraged many patients from undergoing this treatment. Those who chose to proceed had to cope with wearing removable dentures for at least 1 year. Studies have demonstrated that removable denture wearers were reluctant to participate in social activities and embarrassed to speak or eat in public. They exhibited loss of self-esteem, symptoms of depression, premature aging, and even increased risk for early death.1,2
The All-on-4 Protocol
In the past 10 years, implant dentistry has been experiencing exciting changes associated with the introduction of immediate implant-load treatment modalities for fully edentulous patients. The introduction of the All-on-4® (Nobel Biocare, www.nobelbiocare.com) implant treatment concept makes it possible to provide treatment for patients who experienced significant bone loss in the posterior maxilla and mandible without needing complex bone-grafting procedures, which often require a staged approach for full-arch implant rehabilitation. With the All-on-4 protocol, only four implants are required to stabilize a full-arch fixed prosthesis. Therefore, the best sites for implant placement can be identified and utilized, making immediate full-arch prosthesis possible. Tilted posterior maxillary implants can be utilized to avoid a sinus-lift procedure, and tilted mandibular implants make it possible to restore posterior teeth with minimum prosthetic cantilever in the area where axial implant cannot be placed or where short implants, which are not suitable for immediate-load protocol, would have been used.
Predictability of full-arch immediate implant supported fixed prosthesis on the mandible has been successfully described in scientific literature as early as the 1990s. Multicenter studies showed a 85% to 97% success rate for such treatments.3,4 After the All-on-4 concept was introduced by Dr. Paulo Malo in 2002, the overall success rates of tilted implant therapy have exceeded 90% for both the maxilla and mandible.5,6
The All-on-4 treatment concept is not only for the patients who are already edentulous. It can also be successfully applied to patients transitioning from terminal dentition to full-arch implant-supported dentition in one surgical procedure because the use of the available bone is maximized.7 For this type of patient, after the hopeless teeth are removed, two axial implants can be placed in the anterior region, two tilted implants can be placed in the posterior area, and an immediate full-arch temporary screw-retained prosthesis can be fabricated and loaded using multi-unit abutments (Nobel Biocare).
Careful comprehensive treatment planning and establishing good communication among all team members (ie, restorative dentist, surgeon, laboratory technician) are the keys to a successful full-arch immediate-load implant treatment. However, this type of treatment starts with identifying patients suitable for the procedure. A comprehensive diagnosis is important for all implant cases, including 3D imaging with CBCT to evaluate and identify available bone. It should be utilized for all immediate-load implant cases. Sometimes a practitioner may not recognize a good candidate for transitioning from a terminal dentition to an implant-supported dentition utilizing immediate-load treatment concept. One should consider the patient’s esthetic expectations, commitment to lengthy treatment, previous dental experience, and finances when choosing an appropriate treatment plan.
Case Example 1
A 55-year-old woman presented to the office unhappy about the health and appearance of her teeth. A previous dentist had advised that all her teeth had to be removed. However, she delayed treatment, as she was not comfortable with the idea of wearing removable dentures during healing.
Clinical examination revealed moderate-to-severe generalized periodontitis of the remaining dentition, multiple carious lesions, and defective crown restoration. The patient exhibited a slightly collapsed vertical dimension of occlusion (VDO) and supereruption of some upper and lower anterior teeth (Figure 1). After discussing treatment options with the patient, the decision was made to remove the remaining teeth and rehabilitate her dentition utilizing the All-on-4 immediate-load protocol. The smile-line evaluation, for which the patient was asked to produce an exaggerated smile to observe if the attached gingiva was visible, did not reveal a gingival display (Figure 2). Therefore, bone reduction was not necessary to hide the transition line between the prosthesis and soft tissue. This patient’s VDO was only slightly collapsed, and the anterior teeth were present with close-to-adequate lip support. Therefore, All-on-4 treatment could be predictably planned on a semi-adjustable articulator because existing dentition could serve as a guide for an idealized tooth position for an immediate provisional prosthesis.
Once the immediate denture set-up was done, the restorative space between edentulous ridges was evaluated on an articulator and was deemed adequate at 24 mm. This confirmed that bone reduction was not needed to accommodate the prosthesis. According to the literature, the minimum space per arch for a screw-retained prosthesis with metal framework and wraparound acrylic should be 11 to 12 mm.8 A set of dentures was fabricated and converted to an implant-supported prosthesis immediately following implant placement. The patient was happy with the esthetic and functional outcome (Figure 3 and Figure 4).