Immediate-loading techniques, particularly in conjunction with implants placed in the anterior mandible, aim to simplify the treatment process. They reduce the healing time and minimise the delay between the surgical and prosthetic phases. Transgingival implants also help to avoid the much discussed occurrence of a micro-gap in the sensitive peri-implant area. They reduce the overall treatment time and, therefore, the related costs.
I was encouraged to adopt this approach by 40 years of clinical evidence and predictable outcomes. After evaluating the clinical outcome of several cases, I concluded a high success rate could be achieved, with long-term hard tissue stability and successful
maintenance of soft tissue.
Using the XiVE implant system, clinicians can choose between the subgingival and the transgingival versions. Moreover, three different prosthetic solutions are available, specifically meeting patients’ demands.
Background
The standard guidelines for osseointegration of implants include a healing period of three months. Functional loading should be avoided throughout this time. This two-stag approach protects the implant from possible bacterial contamination during the osseointegration phase.
The long healing period can be undesirable for the completely edentulous patient who is obliged to wear a removable temporary prosthesis. The predictability of the original twostage protocol has led to developments to simplify the techniques and reduce the healing time between the surgical and prosthetic phases.
Numerous authors have reported favourable clinical outcomes using single-stage approaches. Several studies also show not only a survival rate, but a success rate that is comparable to that obtained with two-stage procedures. They find no significant differences between the outcomes of these two treatment concepts.
Utilising transgingival implants without immediate loading only avoids the second surgery, rather than completely resolving the difficult circumstances for the patient during the healing period. The resistance of some patients to wearing a removable prosthesis has led to research into simplified treatment protocols with reduced healing time. This has made possible immediate function within 48 hours of implant placement.
Good results have been achieved with immediate-loading techniques, particularly with implants placed in the anterior mandible. Several protocols have been proposed that allow the patient to wear a fixed prosthesis during the osseointegration period, without
compromising long-term success.
A specific protocol, using four transgingival implants placed in the interforaminal area of the mandible, offers the possibility to evaluate three different prosthetic options for restoring edentulous patients. The most important reason for selecting XiVE TG one-piece implants for this approach is the ready availability of prosthetic solutions, with prefabricated or individual parts. In
combination with immediate loading, this offers cost-effective treatment for the patient. The fabrication of a temporary restoration is not necessary and it is possible to utilise the existing prosthesis, combined with prefabricated abutments.
The machined and flared collar of the implant, with the polished neck, allows easy cleaning using interproximal brushes. This can be achieved even by elderly patients or those with physical disabilities.
Prosthetic options
The evidence-based surgical and clinical protocols recommend placing four immediately-loaded implants into the interforaminal area, to support a removable prosthesis. A rigid connection, with a U-shaped bar to retain the superstructure, is advocated. This minimises the micro-motion at the implant-bone interface and allows successful osseointegration.
Depending on the individual clinical situation and the patient’s requirements, it is possible to adopt three different prosthetic approaches. These range from a classic solution, with an overdenture on a U-shaped bar, to a fixed prosthesis with a rigid connection inside.
In order to evaluate the outcome of the immediately-loaded restoration of the edentulous mandible, I studied the long-term results in my clinic. I assessed not only the hard tissue but also the soft tissue stability, along with the influence of adequate maintenance and care.
For each case the related parameters have been checked repeatedly. The outcome has been evaluated for each patient. All the patients were in good health. Prior to the surgery, clinical and X-ray examinations were carried out and, if necessary, CT scans were taken. To allow a comparison of the results, all patients underwent the same surgical protocol.
Implant placement
After a crestal incision, a full thickness mucoperiosteal flap was elevated and four XiVE TG implants were placed into the interforaminal area. The surgical procedure was performed according the manufacturer’s guidelines (figs 1-3).
Good primary stability after placement (at least 35N) was necessary, since this is considered a basic requirement to obtain success with immediate loading. Therefore, the RFA values were evaluated [Osstell] (fig 4). The bone quality, which in this anatomic region is usually D2 or D3, plays an important role in achieving optimal primary stability.
A polyether impression material, either before or after suturing, provides the technician with an accurate guide to the correct soft tissue thickness (figs 5-8). The provisional or definitive prosthesis, depending on the treatment concept, can be fabricated and provided to the patient within 48 hours.
The most economic and simplest prosthetic method is to incorporate an overdenture on a U-shaped bar (figs 9, 10). The superstructure can be designed with or without pink plastic, depending on the vertical occlusion dimension (figs 11-14).
Usually the sutures are removed after 14 days and a follow-up visit is scheduled after three months. The first three months after surgery are very important for achieving successful osseointegration of the implants and the healing of the soft tissue. For this reason patients are advised to follow a soft diet during the first month of healing and oral hygiene instructions are provided.
For a provisional rehabilitation, healing is checked and the osseointegration status is evaluated three months after the incorporation of the temporary restoration. Then the definitive prosthesis can be fabricated.
The manufacturing of full-arch, fixed, implant-supported bridges with the use of the traditional ‘lost wax’ technique remains a technical challenge. Distortion of the alloy during casting, and subsequent heating cycles during the porcelain build-up, may cause problems.
The fit of the final prosthetic rehabilitation can be significantly improved by utilising CAD/CAM technology in the manufacturing of long-span or full-arch titanium bridges. The Atlantis Isus system helps to create a very accurate definitive alloy frame that can be finalised either with ceramic or composite (figs 15-17).
To ensure positive long-term results, a regular recall every six months is important, to verify stability and health of the implants, prosthesis and tissues. It also provides the opportunity to check oral hygiene.
Conclusion
Some studies described in current literature evaluate the healing of soft tissue and compare the difference between submerged and nonsubmerged implants. All of these studies confirm that the biologic width dimension for one-piece implants was significantly smaller than for twopiece implants with a microgap. In addition, for one-piece implants, the tip of the gingival margin was located significantly more coronally, compared to two-piece implants.
These findings suggest that the mucosal microvasculature adapts and forms in a way more similar to natural teeth around one piece non-submerged implants, compared to either two-piece non-submerged or submerged implants. Clinically, mature peri-implant soft tissue seems to be established four weeks after implant placement for a one-stage surgical protocol.
Osseointegration is a prerequisite for long-term implant stability. However, a complete soft tissue seal to the titanium surface at the most coronal aspect of the implant body is required to prevent microbacterial settlement. It avoids the establishment of pathologic environments that may interfere with the osseointegration process, as well as preserving both hard and soft tissue.
Moreover, the literature shows statistically significant differences in the mean value of keratinised tissue height after surgery. It was significantly reduced for submerged implants compared to unsubmerged implants groups. The longest observation period
for these cases is more than eight years, showing the perfect integration of hard tissue, with successful healing and adaptation of soft tissue above and around the implant neck (fig 18).
Based on the high implant survival rate and favourable tissue response, the one-piece implant can be recommended for clinical use. Immediate loading is particularly endorsed, since this offers the additional advantages of economical rehabilitation of the endentulous mandible.