Standard panoramic radiograph (a) shows little evidence of a problem with anterior maxillary implants (arrowed). However reformatted axial (b) and cross-sectional (c) views from CBCT examination show that 7 years later the immediately placed implants are entirely outside of the bony envelope of the maxilla
Given the anatomical constraints and surgical challenges, attention to detail in prosthetic planning and in provisional and definitive phases of prosthetic reconstruction is also of paramount importance. Poor prosthetic planning may not only lead to aesthetic and prosthetic complications (see previous chapters in this series), but might also lead to inadequate surgical planning, inadequate surgical preparation of the jaw, inappropriate implant positioning, inappropriate loading and ultimately implant failure.
In this chapter, we describe some of the compromises and complications which may lead to failure in graftless treatments, and describe strategies that the authors have used to manage complications and salvage situations where there has been failure.
15.1.1 Implant Failure
Like any other implant treatment, there is always a risk of implant failure. Clearly most patients who need graftless treatments have not been very successful at maintaining their teeth, and many of these individuals may not be adept at looking after their implants either. All the recognised risks of implant failure will apply; smokers [3], those who suffer from periodontal disease [4], diabetics [5], patients prescribed bisphosphonates [6] and individuals in poor health [7] will all be at risk of implant failure. Additional risks relate to nearby critical anatomy, biomechanical challenges, and, also, most importantly management of patient expectations.

These patients believed that they were to have ‘All-on-4’ treatment. In this case (a), the maxillary implants are all positioned anteriorly for this inadequate reconstruction which failed with fracture of three abutment screws and failure of the remaining functional implant. The panoramic radiograph suggests that no attempt has been made to fully utilise the available jaw to broaden the span of implant support (b). Note the presence of an intact opposing dentition. In this case (c) the implants are also poorly positioned anteriorly—note the fractured abutment screw in the right rear implant. The patient was provided with a much repaired and poorly constructed and totally inadequate provisional prosthesis (d), which was still in use 2 years after surgery
Numerous studies have shown excellent outcomes for such treatments [8], though for an individual who experiences a failure a proven high success rate in the literature will be of little solace. In the event of early implant failure soon after surgery, loss of support as the implant loosens may lead to an escalation in the complexity of the problem, with the potential for overload or fracture of the provisional prosthesis, failure of prosthetic components and failure of other implants involved in the reconstruction. The use of a provisional prosthesis is important as it will serve to splint and stabilise the implant during the healing period. It is also key, in that if an implant fails early on, it does so before an investment in the definitive fixed prosthesis has been made.
A poorly made or insubstantial provisional bridge may fracture and cause overload of an implant. Where atrophy is minimal and the jaw must be reduced in order to find space for the prosthesis, inadequate reduction may result in the production of a weak provisional prosthesis; early fracture of this prosthesis may lead to implant failure. On the other hand, excessive jaw reduction may remove bone that might prove valuable later in the event of a failure—patients must be specifically consented for jaw reduction.
Where there is an early failure, patient management will be more straightforward if another suitable implant site is immediately available to augment support for the bridgework, or if there is at least a removable prosthesis to hand. Easy access to laboratory services and possession of technical skills will make all the difference to prompt management. If anchorage for the remaining implants is less than ideal, or if two or more implants fail, or healing of newly placed implants is not advanced at the time of failure, there may well be a need for the patient to wear a removable prosthesis as an interim measure. Patients may become upset if then asked to wear a removable prosthesis, particularly where multiple teeth have been removed at the time of surgery and when the patient has no experience of using a removable prosthesis. It is therefore sensible to discuss failure, and to make contemporaneous notes of this discussion long before treatment, in addition to providing clear written information preoperatively.
In the case of later implant failure, there is the advantage that remaining implants may be stable, and dental extraction sites will be in a more advanced healed state.

This 60-year-old smoker was referred with multiple implants affected by peri-implantitis (a, b). Removing these long implants would be highly destructive, so a decision was made to attempt to maintain them for the time being with surgical debridement (c), addressing the smoking and maintenance issues for now

A 65-year-old patient developed rapidly progressive bone loss associated with just one of four mandibular implants (a—4 years post-surgery, b—just 3 years later). Poor cleaning (c), depression and loss of diabetic control may all have been factors. With removal of the implant, the return of diabetic control and a return to satisfactory maintenance behaviour the situation seemed reasonably stable a year later, with the patient functioning on three of the four original implants
15.1.2 Removing Failing Implants

Various approaches to implant removal . (a) With a trephine. (b) With an ultrasonic device. (c) High-speed surgical turbine with rear-venting exhaust. (d) Reverse torque implant retrieval tool
15.1.3 ‘Rescue’ Implants


Panoramic radiograph (a), showing implant treatment in both jaws for a patient who had advanced periodontal disease. The asymptomatic implant in the upper right lateral incisor position was found to have failed 3 months after surgery when the patient presented with a fracture of her temporary prosthesis. Reformatted panoramic (b) and cross section (c) reconstructed from CBCT, 12 weeks after removal of failed implant. Note extensive bone loss only really visible in the cross section; replacement of the implant consequently delayed, with the reconstruction completed 6 months later (d)





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