If we aim for good prognosis .... treatment planning is the key to success in every treatment regardless of implant dentistry. Treatment planning for restorative implantology has many aspects which are to be considered. The important ones being:

Medical history, oral examination, imaging techniques, the choice of fixed vs removable. These four along with skilful surgical placement will avoid any failures. The subject is vast and if we consider these, success rates can be increased and failures avoided.

Regards,

Patient selection (account for bone volume and quality along with patient's oral hygiene habits, absence of systemic diseases ), sterile environment, tissue handling. Type and quality of implants is also important, latest implants have their surface treated with biomaterials (e.g: plasma) for better osteointegration. Placement and positioning of the implant is also critical. Etc

Diagnosis, diagnosis, diagnosis. 3-D planning aids in understanding of bone the density and quality of the bone. Interactive software allow for precise planning of implants within receptors site, but without an understanding of the desired restorative result you would not be practicing "true restoratively-driven" implant reconstruction. Therefore diagnostic wax-ups or duplicates of the patient's existing denture, combined with the CBCT dataset aids greatly in making informed decisions, and relating the propose tooth position to the underlying bone.

Risk factors for peri-implant diseases

At present there are limited scienti c data on the factors increasing the risk for peri-implant diseases, but poor oral hygiene, a history of periodontitis, and smoking have all been identi ed to increase the risk of peri- implantitis.

I would support all answers here.

But in the diagnostics the oponents must be considered.

In all publications, we get no information abut the the oponents.

The interaproximal place between implants and for me screwable prosthodontic are very important.

for long term success bruxism patient should be considered.  Meticulous treatment plan should be prescribed for those patients, otherwise retention screw or even the implant itself may be subject to fracture. 

I would recommend attention to the interocclusal space, interarch relationship and favorable crown implant ratio. Sometimes all others factors are favorable like available bone, density, medical history, absence of parafunction but we dont pay attention to above factors. Our ultimate goal is a good functional as well as aesthetic prosthesis for the patient along with the longevity of the implant.

I think here you can find some answers:

http://www.nature.com/bdj/journal/v195/n4/full/4810435a.html

Preventive strategies for patients requiring osseointegrated oral implant treatment, an article from British Dental Journal.

doi:10.1038/sj.bdj.4810435

In my view, all the factors right from treatment planning including imaging, patient compliance, medical condition, biological condition of  implant site, types of implants, para-functional habit ,surgical procedure, maintenance and prosthetic loading are important for the success of an implant. overlooking any one of them may end up with failure.

In issue 1 of IJOMI in 1986, Albrektsson described factors for consideration. These remain true today. I will summarize and paraphrase and p[rovide a few nuances:

Implant factors: biocompatible material, appropriate macro and micro design, etc.

Patient factors: health, habits, cooperation, acceptable bone quality and quantity, remaining dentition, opposing dentition (1.     Becktor, J. P., S. E. Eckert, S. Isaksson and E. E. Keller (2002). "The influence of mandibular dentition on implant failures in bone-grafted edentulous maxillae." Int J Oral Maxillofac Implants 17(1): 69-77.), etc.

Surgical factors: gentle surgery, appropriate drilling speed, drilling action, cooling using irrigation, avoid critical temperatures (43 degrees C), etc. 

Prosthetic factors: occlusion, avoidance of bruising patients, distribution of forces, axial loading, appropriate number and dimensions of implants, etc.

Albrektsson, in that same seminal article, described success criteria that, for all intents and purposes, remain true today.

So, how do we put this all together?  Well, there is no one factor that definitely leads to implant failure.  the sacred cows of implant dentistry have  been described and there is no one issue that leads to success or failure.

Efforts to show that occlusal overload is a negative prognostic factor have all failed to show this with the exception of the Isidor article in which implant prostheses in monkeys were placed 3 mm high in occlusion (an unrealistic amount) only to find that the opposing teeth intruded.  When they added another 3 mm (total 6 mm high) the implants finally failed.  This is the equivalent of using TNT to kill flies.

Certainly patients who smoke excessively are putting themselves at risk.  2+ packs a day are a problem.  Fewer than 10 per day  seems to be no issue, between 10 and 40 is uncertain.  Bain and Moy identified smoking as a risk many years ago.  With micgrotextured implants of today we don't see a problem until the number of cigarettes goes way up. ( Balshe, A. A., D. A. Assad, S. E. Eckert, S. Koka and A. L. Weaver (2009). "A retrospective study of the survival of smooth- and rough-surface dental implants." Int J Oral Maxillofac Implants 24(6): 1113-1118. AND Balshe, A. A., S. E. Eckert, S. Koka, D. A. Assad and A. L. Weaver (2008). "The effects of smoking on the survival of smooth- and rough-surface dental implants." Int J Oral Maxillofac Implants 23(6): 1117-1122.)

Controlled diabetes, immunodeficiency, osteoporosis, etc. do not seem, as single entities, to be significant risk factors.

So, what causes implants to fail? It is likely that there are accumulated risks from a number of factors.  Identifying these with certainty prior to implant treatment would be a nice idea but we often lack insight into the multitude of risk factors.

What about predictive factors?  Hounsfield units, insertion torque, ISQ values, Periotest have all been described.  The think that damages implants making them fail is micro motion.  If you can limit micro motion to less than 100 micrometers this seems to help.  The other factors are surrogates, many of them are lacking as positive or negative predictive factors.

Obviously we cannot depend on Watson, the supercomputer, to tell us how to manage the use of implants and the myriad of factors that influence implant performance.  We have lots of factors that need to be discussed.  In many instances we see failure without one specific cause.  The reality is that it is multifactorial although there might be a factor or two that are predominant.  Determining what those factors are is not always simple, intuitive or even correct.

It surprises me when an implant fails and a clinician blames it on something...let's say smoking.  Of course we have thousands of implants functioning fine in smokers, why have those not failed?  The answer is one of cumulative risk, not isolated risk with the possible exception of uncontrolled force that creates micro motion above the threshold which has been described as 100 micro meters and yet even that number is subject to individual biologic variability.

After all these years, I still tend to think of what Albrektsson stated.  It makes sense.  He described four categories of factors, absolute failure in any of those categories will likely result in failure of the implant but absolute failure is unusual unless a clinician is totally unskilled or lacking in knowledge.  Instead failure and clinical complications are usually the result of cumulative errors.

In issue 1 of IJOMI in 1986, Albrektsson described factors for consideration. These remain true today. I will summarize and paraphrase and p[rovide a few nuances:

Implant factors: biocompatible material, appropriate macro and micro design, etc.

Patient factors: health, habits, cooperation, acceptable bone quality and quantity, remaining dentition, opposing dentition (1.     Becktor, J. P., S. E. Eckert, S. Isaksson and E. E. Keller (2002). "The influence of mandibular dentition on implant failures in bone-grafted edentulous maxillae." Int J Oral Maxillofac Implants 17(1): 69-77.), etc.

Surgical factors: gentle surgery, appropriate drilling speed, drilling action, cooling using irrigation, avoid critical temperatures (43 degrees C), etc. 

Prosthetic factors: occlusion, avoidance of bruising patients, distribution of forces, axial loading, appropriate number and dimensions of implants, etc.

Albrektsson, in that same seminal article, described success criteria that, for all intents and purposes, remain true today.

So, how do we put this all together?  Well, there is no one factor that definitely leads to implant failure.  the sacred cows of implant dentistry have  been described and there is no one issue that leads to success or failure.

Efforts to show that occlusal overload is a negative prognostic factor have all failed to show this with the exception of the Isidor article in which implant prostheses in monkeys were placed 3 mm high in occlusion (an unrealistic amount) only to find that the opposing teeth intruded.  When they added another 3 mm (total 6 mm high) the implants finally failed.  This is the equivalent of using TNT to kill flies.

Certainly patients who smoke excessively are putting themselves at risk.  2+ packs a day are a problem.  Fewer than 10 per day  seems to be no issue, between 10 and 40 is uncertain.  Bain and Moy identified smoking as a risk many years ago.  With micgrotextured implants of today we don't see a problem until the number of cigarettes goes way up. ( Balshe, A. A., D. A. Assad, S. E. Eckert, S. Koka and A. L. Weaver (2009). "A retrospective study of the survival of smooth- and rough-surface dental implants." Int J Oral Maxillofac Implants 24(6): 1113-1118. AND Balshe, A. A., S. E. Eckert, S. Koka, D. A. Assad and A. L. Weaver (2008). "The effects of smoking on the survival of smooth- and rough-surface dental implants." Int J Oral Maxillofac Implants 23(6): 1117-1122.)

Controlled diabetes, immunodeficiency, osteoporosis, etc. do not seem, as single entities, to be significant risk factors.

So, what causes implants to fail? It is likely that there are accumulated risks from a number of factors.  Identifying these with certainty prior to implant treatment would be a nice idea but we often lack insight into the multitude of risk factors.

What about predictive factors?  Hounsfield units, insertion torque, ISQ values, Periotest have all been described.  The think that damages implants making them fail is micro motion.  If you can limit micro motion to less than 100 micrometers this seems to help.  The other factors are surrogates, many of them are lacking as positive or negative predictive factors.

Obviously we cannot depend on Watson, the supercomputer, to tell us how to manage the use of implants and the myriad of factors that influence implant performance.  We have lots of factors that need to be discussed.  In many instances we see failure without one specific cause.  The reality is that it is multifactorial although there might be a factor or two that are predominant.  Determining what those factors are is not always simple, intuitive or even correct.

It surprises me when an implant fails and a clinician blames it on something...let's say smoking.  Of course we have thousands of implants functioning fine in smokers, why have those not failed?  The answer is one of cumulative risk, not isolated risk with the possible exception of uncontrolled force that creates micro motion above the threshold which has been described as 100 micro meters and yet even that number is subject to individual biologic variability.

After all these years, I still tend to think of what Albrektsson stated.  It makes sense.  He described four categories of factors, absolute failure in any of those categories will likely result in failure of the implant but absolute failure is unusual unless a clinician is totally unskilled or lacking in knowledge.  Instead failure and clinical complications are usually the result of cumulative errors.

Dear Dr. Eckert,

I totally agree with the all the factors that your stressed out. I would like to highlight also the fact that primary stability is still regarded as a crucial factor to achieve biologic stability. On the counterpart, it is interesting the number of recent reports showing that high insertion torque may have a detrimental effect of crestal bone stability as well as upon osseointegration. For instance, Cha et al. (JDR 2015) demonstrated in a multiscale analysis that high IT more than doubles this zone of dead and dying osteocytes. As a result, peri-implant bone develops micro-fractures, bone resorption is increased, and bone formation is decreased. Likewise, Simons (COIR 2014) showed that the thicker the cortical bone layer was at implant placement (and thus, higher IT), the greater the marginal bone resorption was. Therefore, I would consider further inadequate implant drilling protocol along with high bone density (and not quality since these from these reports might be extracted that poorer bone might be biologically better - richer vascularity compared with denser bone) might play important roles on implant failure. Interestingly, the recent reports by Derks (JDR 2015,2016) showed twice as much peri-implantitis and implant failure in areas of denser bone (mandible) compared to the maxilla.

Best,

Alberto

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