As a practitioner of implant dentistry for the past 34 years, I am seeing an increasingly common problem: lack of understanding of ailing and failing implants. What are the clear indicators of failure, which cases can be treated, and when should you cut your losses and remove the implant(s)? Implant mobility or a radiographically definitive radiolucency around an implant are clear signs of non-integration or loss of integration, both indications that the implant must be removed. An implant in one of the above conditions should be considered an ‘Absolute Failure’. But what about that implant that has a few threads exposed above the osseous receptor site? (No specific number here on purpose – see table). Both dentists and patients are hesitant to remove an asymptomatic ailing implant, particularly when function has not been compromised. Keep the patient informed! In many cases, a ‘wait and see’ attitude is appropriate (provided the patient is informed about the chances of progression and its consequences). Often, monitoring early bone loss leads to confirmation of progression or lack thereof (valuable information leading to the selection of the treatment of choice).
In my opinion, if an implant is failing, it is the responsibility of the doctor to not only inform the patient of the problem, but to illustrate the problems that have evolved over a given period of time — with the use of radiographs (showing the actual problems themselves) or by diagram. This seems to be the easiest for the patient to comprehend or understand, and with most of the problems that arise from ailing/failing implants, the majority of the cases that are brought before the college are from lack of communication between the dentist and the patient. If some form of communication or dialogue had been opened up when the problem first became apparent, the patient and the dentist would be mutually more receptive to the sequelae and more likely to be on board with management of the problem. There then seems to be a mutual respect for the problem and the patients become more sympathetic with the problem the doctor is facing from a management point of view.
There are a myriad of reasons that lead to failing implants. Although the understanding of the etiology, and in particular, the factors that initiate these events are poorly understood, there are a number of clearly defined ‘usual suspects’ that can be examined. For example, improper or non-rigid fixation of the implant at placement; preparing the receptor site with dull drills which overheat the bone (causing necrosis of the bone immediately adjacent to the implant body); contamination on the implant body during placement (leading to infection); improper biomechanical forces on the implant body during function (either from improper occlusion or improper axis orientation during initial placement — or a badly positioned implant which requires a cantilever prosthesis to completely fill the edentulous space); and patient health issues like smoking, diabetes, bisphosphonates, lupus or other auto-immune diseases. These are but a few of what I consider possible causative factors. Recently, I read of a case in which the patient developed what is now called ‘Spontaneous Osteonecrosis of the Jaw’. This involved treatment in which a sinus elevation and implant placement were conducted in the posterior second quadrant maxilla of a female on bisphosphonates years earlier. She had completely healed and the implants were functional until this ‘spontaneous osteonecrosis’ occurred. The implants and necrotic bone required removal. The patient required hospitalization and was placed on IV antibiotic therapy until the condition was neutralized and under control. This condition is highly unusual, but if a patient is considering implant therapy and is taking bisphosphonates, this is something that I will now be discussing before treatment commences.
There is also a ‘grouping’ of the implants clinical conditions that can determine the treatment that would be expected to be rendered by the implant dentist. There are generally four groups or categories of implant conditions (Misch: Contemporary Implant Dentistry — 3rd Edition–Mosby, 2008) which are managed in four different ways (depending on the severity of the implants’ clinical and radiographic condition) (Table).
These categories serve as a guide only and are intended to give us some direction when considering treatment options. For example, not all implants need to be removed when they have more than 7mm of bone loss. I have seen some referred cases with an excessive amount of bone loss that I have been ‘babysitting’ for years. The cases that come to mind are where implants have been placed with the platform flush, with the bone, after an autogenous bone grafted ridge, and on occasion, the graft will resorb or ‘melt away’, leaving the original clinical level of bone (the original bone level before grafting). The implants seem to ‘stabilize’ in this original ‘host’ bone but the threads directly below the platform become either exposed, or covered in soft tissue and render no integral support to the implant and/or prosthesis. In some of these cases (with appropriate hygiene and professional visits), it is possible to maintain these implants in function for years before they have to be removed (even though they might originally be considered to be failures with numerous threads exposed above the bone). The deleterious factor here was not occlusal overload, or bacterial in nature, it was what we now know to be considered ‘a variation of normal’ when autogenous blocks are used to enhance bone volume in any particular site (this doesn’t seem to be the case when using allografts or xenografts). If the patient has had an autogenous bone graft, this is something that should be discussed with the patient, and something the patient should be informed about before surgery.
An implant that falls into either category #2 or #3 (from the above chart), can sometimes be treated surgically and chemically with ‘Thread reduction and Citric Acid Rinse’ (40% – PH-1) before re-grafting the peri-implant defect. Thirty plus years ago, through the research of a great colleague Dr. Roland Meffert, we also used liquid tetracycline [50 mg/ml – PH-2] rinse to etch and clean the thread area of failing implants. This is, of course, dependant on the amount of time that has passed since the implant was placed. If the implant was placed within the year, then I would consider it a failure (for whatever reason) and would remove it. The patient should be kept in the loop with ‘expectations’ and ‘possible complications’ – no matter what treatment you are going to perform. The patient should also be aware that under these new circumstances, the implant needs a little more ‘babysitting’ and that the eventual outcome might be removal, regardless of the treatment performed. If an implant develops peri-implantitis and is considered to be ‘at risk’, we should analyze it and all of the factors that we feel have been contributing factors in the worsened condition of the implant. Once we have identified the suspected cause of the peri-implantitis, then we can apply the treatment that addresses the suspected cause and the decision of ‘what to do next’ should become pretty clear.
I find that patients are generally very receptive when they are kept up to date with the progress (or lack thereof) of their implant condition. Not all dental implants will
last ‘forever’, in the same way that hip replacements do not last forever. I love to use this analogy before I even start the procedure. Although dental implants have an extremely high success rate, problems can develop that need to be addressed. It’s not having these problems, but how we handle and address them that demonstrate a high level of professionalism – and that should be expected by the patients and be delivered by us as professionals.OH
Dr. Nicolucci is president of the Canadian Society of Oral Implantology and is Oral Health’s editorial board member for Implantology.