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75 – Why Would an Implant Fail?

Hi there. This is the Perio Patient Podcast, a podcast for my patients and anyone else who cares to listen. My name is Dr. Ben Young and I am a periodontist living and working in the beautiful city of San Antonio, in the great state of Texas.  

Today’s podcast is in response to a question I received by email which is simply this: Why Would an Implant Fail? 

It’s a fair question. Dental implants are expensive devices and there is certainly an assumption that they will last the rest of someone’s life.  

From an engineering standpoint, this looks realistic and in fact it is true that of all the dental restorations we have available in treatment today, the dental implant lasts the longest. And I’ve said it before on this podcast that the development of the modern dental implant is an extraordinary gamechanger that has occurred in my lifetime. Let me put it this way. While I was in dental school, the most popular dental implants were of different designs and techniques that no longer exist and we were taught at that time that the risks for placing dental implants were generally too high for the dental school to be encouraging anyone except research institutions to get involved. Then all of a sudden, and around the time I was beginning my periodontics residency, the current implant was introduced and I was in the class, as a lowly resident watching from the back row, at Wilford Hall Medical Center when some of the very first lectures and courses in North America were being delivered. This was 1985. On the one hand, we have come a long way baby with more knowledge and methods for improving the outcome of dental implant delivery and restorations, but on the other hand, the basic principles that were introduced back then in how to enable bone cells to essentially fuse to the implant surface are still in play. 

But with time, we also have had the time to see implant failures, and I spoke about the three types of failure in Episode 68, About Dental Implants. I’ll link to the podcast in the notes below. 

https://theperiopatientpodcast.libsyn.com/episode-68-about-dental-implants

To go even further in this area today, I did a quick literature search on causes of implant failure and these are some other things to consider. 

I will list these articles and links on the script for this podcast published in the blog section of my website and I will give a link in the notes below to get you to where this script is located should you are interested. 

In the Int J Oral Maxillofac Implants. 2009;24 Suppl:39-68. There was a report entitled: History of treated periodontitis and smoking as risks for implant therapy 

Lisa J A Heitz-Mayfield1, Guy Huynh-Ba 

https://pubmed.ncbi.nlm.nih.gov/19885434/

They stated that there is an increased risk of peri-implantitis in smokers compared with nonsmokers (reported odds ratios from 3.6 to 4.6 what this means is that the odds of a problem occurring if you are a smoker over a non-smoker is 3.6 to 4.6 times greater). The combination of a history of treated periodontitis and smoking increases the risk of implant failure and peri-implant bone loss. 

Here is an article published in 2018 studying nicotine as a predictor of success or failure in dental implants. It was a retrospective study, meaning it looked at data collected during the routine course of treatment. A prospective study (prospective meaning looking forward) is a designed study usually with a control and test group.  

The results showed first of all the males had a slightly greater failure rate compared to females. For this reason they broke the results out for males and females separately. Let’s start with males. If the gentlemen smoked their failure rate was 6.13% and if they didn’t smoke their failure rate was 2.98%. Rounding out to 6% failure of smoking men and 3% failure of non-smoking men. It shows first of all a doubling of risk and second of all the success rate was in the mid to high 90’s regardless if you smoked or did not.  

For smoking women, the failure rate was 5% and non-smoking women was 0.9%. This actually shows a worse response for women if they smoked compared to not smoking compared with men. Again, the success rate for both groups is high.  

One other point to make here. I think this report actually shows the weakness of a retrospective study because of the difference seen between men and women because unless there is some genetic hormonal reason for the differences, it is really unclear, at least to me, that a real, or clinically significant, difference exists.  

Which brings me to a little nuanced point about statistics it is useful for you to understand. Something can be statistically significant and clinically insignificant.  In other words, people can tell you that a study showed a significant difference between those who took brand A and those who took brand B, but it may still not be clinically significant. Yes, it is easy to, let’s say, misinform, with statistics.  

The results showed that in Group I, males had 6.13% and females had 5% dental implant failure. Overall failure rate in Group I was 5.56%. In Group II, males had 2.98% and females had 0.9% failure. Overall failure rate in Group II was 2.35%. The difference between both groups was statistically significant (P < 0.05). 

Another thing to consider when looking at implant failure has to do with how the implant will be used to restore a mouth. Will it be used to replace a single tooth, a few teeth, or the entire arch of teeth. Here is a study entitled:  

Clin Implant Dent Relat Res  . 2006;8(2):77-86. 

 doi: 10.1111/j.1708-8208.2006.00002.x. 

Early complete failures of fixed implant-supported prostheses in the edentulous maxilla: a 3-year analysis of 17 consecutive cluster failure patients 

Torsten Jemt1, Per Häger 

The were looking at what they described as Clusters of implant failures in the edentulous maxilla (upper jaw) that seemed to to be occurring in some patients. It was a retrospective study of 1,267 consecutively treated patients in one clinic. The failures they were studying were of those who had multiple implants failed under teeth that were screw attached. Out of 1,267 consecutively treated patients only 17 met the criteria they wanted to study. This is a failure rate of 1.3%. They speculated on implant lengths but most of the implants they placed they stated were shorter so this would likely have skewed the data. In addition they thought that there was a greater risk with smokers and those who had periodontal disease in the opposing arch – which in this study would be the lower jaw or mandible.  

Background: Clusters of implant failures in the edentulous maxilla seem to occur in some patients. To create groups for analysis with higher numbers of these patients implies large original groups for inclusion. 

Purpose: The aim of this study was to retrospectively describe and compare a group of “cluster failure patients” with randomly selected patients treated in the edentulous maxilla. 

Materials and methods: From a group of 1,267 consecutively treated patients in one clinic, all patients presenting failing fixed implant-supported prostheses within the first 3 years of follow-up were included. All patients were treated with turned titanium implants using two-stage surgery. A control group of equal number of patients were created for comparison. Data on patients were retrospectively retrieved from their records, and compared. 

Results: Seventeen patients (1.3%) met the inclusion criteria in the entire group. The bone resorption index revealed less bone quantity in the study group (p < .05) during implant placement, but there was no difference regarding primary implant stability at first-stage surgery. The distribution of short and long implants showed relatively higher number of short implants in the study group (p < .05), and more patients had a presurgical discussion on the risk of implant failure prior to treatment in this group (p < .05). Only 5 out of 102 implants (4.9%) were lost before prosthesis placement as compared to 38 and 25 lost implants during the following two years in the study group. Smoking habits and signs of bone loss related to periodontitis in the lower dentition were more frequent in the study group, but did not reach a significant level (p > .05). 

Conclusion: The results indicate that bone quantity, reflected in fixture length, has a significant impact on increased implant failure risk. Other factors of interest as predictors for implant failures could be smoking habits and also possibly signs of periodontitis in the opposing dentition. 

Another study looked at implant length and diameter on survival rates. This one was published in 2006 and stated that “The use of a short or wide implant may be considered in sites thought unfavorable for implant success, such as those associated with bone resorption or previous injury and trauma.” I do think one of the helpful trends in dental implant placement is the finding that usually longer implants are no better than what were once considered short implants. But there are limits even to this. The same with diameters of implants. It is possible to reduce the metal of the implant down to a point where it is much weaker. Also when implant diameters become too small – in the area of what we call mini-implants – then restorative options are fewer. Are there indications for mini-implants? Yes, when there is not enough bone volume for a standard diameter implant which are usually just under 4 mm in diameter.  

Clin Oral Implants Res  . 2006 Oct;17 Suppl 2:35-51. 

 doi: 10.1111/j.1600-0501.2006.01349.x. 

Impact of implant length and diameter on survival rates 

Franck Renouard1, David Nisand 

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0501.2006.01349.x

The use of a short or wide implant may be considered in sites thought unfavourable for implant success, such as those associated with bone resorption or previous injury and trauma.  

Here is a 

A 10 years retrospective study of assessment of prevalence and risk factors of dental implants failures 

Rohit Singh1, Anuj Singh Parihar2, Vikas Vaibhav3, Kunal Kumar4, Revati Singh4, Jeethu John Jerry5 

https://pubmed.ncbi.nlm.nih.gov/32509661/

Aim: The present study was conducted to determine the prevalence rate of dental implants failure and risk factors affecting dental implant outcome. 

Materials and methods: The present retrospective study was conducted on 826 patients who received 1420 dental implants in both genders. Length of implant, diameter of implant, location of implant, and bone quality were recorded. Risk factors such as habit of smoking, history of diabetes, hypertension, etc., were recorded. 

Results: In 516 males, 832 dental implants and in 310 females, 588 dental implants were placed. Maximum dental implant failure was seen with length <10 mm (16%), with diameter <3.75 mm, and with type IV bone (20.6%). The difference found to be significant (P < 0.05). Maximum dental implant failures were seen with smoking (37%) followed by hypertension (20.8%), diabetes (20.3%), and CVDs (18.7%). Healthy patients had the lowest failure rate (4.37%). 

Conclusion: Dental implant failure was high in type IV bone, dental implant with <3.75 mm diameter, dental implant with length <10.0 mm, and among smokers. 

It listed a number of risks factors to include bone density (the softest bone, think thin frail elderly people with osteoporosis), smoking, hypertension, diabetes, cerebral vascular disease.  

Well let’s leave it there. I think you get the idea, that implant failure does exists. It is small. There are risk factors. Finally, go back and listen to my podcast on Vitamin D if you have not. Some of the problems surgeons have been believing were due to infection turn out to more likely be due to Vitamin D deficiency.  

Well, let’s stop here. Go rest your brain.  

This has been The Perio Patient Podcast and I am still Dr. Ben Young. Thanks for listening. Bye for now.  

List of Articles: 

History of treated periodontitis and smoking as risks for implant therapy 

Lisa J A Heitz-Mayfield1, Guy Huynh-Ba 

https://pubmed.ncbi.nlm.nih.gov/19885434/

J Family Med Prim Care  . 2020 Feb 28;9(2):729-734. 

 doi: 10.4103/jfmpc.jfmpc_1023_19. eCollection 2020 Feb. 

Evaluation of marginal bone loss around dental implants in cigarette smokers and nonsmokers. A comparative study 

Jazib Nazeer1, Rohit Singh2, Prerna Suri3, C D Mouneshkumar4, Shweta Bhardwaj5, Md Asad Iqubal6, Dinesh7 

https://pubmed.ncbi.nlm.nih.gov/32318410/

The crestal bone loss around dental implants was significantly greater in smokers (Group I) as compared to nonsmokers (Group II) irrespective of the duration of loading (P < 0.001). Marginal bone loss did vary significantly by location in either groups. 

J Family Med Prim Care  . 2020 Mar 26;9(3):1617-1619. 

 doi: 10.4103/jfmpc.jfmpc_1171_19. eCollection 2020 Mar. 

J Family Med Prim Care  . 2020 Feb 28;9(2):729-734. 

 doi: 10.4103/jfmpc.jfmpc_1023_19. eCollection 2020 Feb. 

Evaluation of marginal bone loss around dental implants in cigarette smokers and nonsmokers. A comparative study 

Jazib Nazeer1, Rohit Singh2, Prerna Suri3, C D Mouneshkumar4, Shweta Bhardwaj5, Md Asad Iqubal6, Dinesh7 

https://pubmed.ncbi.nlm.nih.gov/32318410/

The crestal bone loss around dental implants was significantly greater in smokers (Group I) as compared to nonsmokers (Group II) irrespective of the duration of loading (P < 0.001). Marginal bone loss did vary significantly by location in either groups. 

J Family Med Prim Care  . 2020 Mar 26;9(3):1617-1619. 

 doi: 10.4103/jfmpc.jfmpc_1171_19. eCollection 2020 Mar. 

J Int Soc Prev Community Dent    . Nov-Dec 2017;7(6):351-355. 

 doi: 10.4103/jispcd.JISPCD_380_17. Epub 2017 Dec 29. 

Factors Affecting the Survival Rate of Dental Implants: A Retrospective Study 

Sonal Raikar1, Pratim Talukdar2, Sarala Kumari3, Sangram Kumar Panda4, Vinni Mary Oommen5, Arvind Prasad6 

https://pubmed.ncbi.nlm.nih.gov/29387619/

Age, length of implant, diameter of implant, bone quality, and region of implant are factors determining the survival rate of implants. We found that implant above 11.5 mm length, and with diameter <3.75 mm, placed in the mandibular posterior region, in Type III bone showed maximum failures. 

Int J Oral Maxillofac Implants   . Jul-Aug 2006;21(4):607-14. 

Private practice results of screw-type tapered implants: survival and evaluation of risk factors 

Torsten Mundt1, Florian Mack, Christian Schwahn, Reiner Biffar 

https://pubmed.ncbi.nlm.nih.gov/16955613/

Discussion: Higher failure rates for former smokers and a dose-response effect between duration of smoking and implant failure rates suggested that permanent tissue damage from smoking may occur in addition to immediate local and systemic effects. The frequency of prosthetic complications was comparable to other studies. 

Conclusions: Screw-type tapered implants placed in a private dental office demonstrated a cumulative survival rate of 91.8%. The relative risk of implant failure increased with the duration of smoking. 

Int J Oral Maxillofac Implants   . Sep-Oct 2008;23(5):905-10. 

Effect of osteoporotic status on the survival of titanium dental implants 

Christopher M Holahan1, Sreenivas Koka, Kurt A Kennel, Amy L Weaver, Daniel A Assad, Frederick J Regennitter, Deepak Kademani 

https://pubmed.ncbi.nlm.nih.gov/19014161/

Conclusions: Based upon the data derived from this retrospective study of 192 women at least 50 years of age at the time of implant placement, the following observations were made: (1) a diagnosis of osteoporosis and osteopenia did not contribute to increased risk of implant failure and (2) implants placed in patients who were smokers at the time of implant placement were 2.6 times more likely to fail than implants placed in nonsmokers. Based on these data, a diagnosis of osteoporosis or osteopenia is not a contraindication to dental implant therapy. 

Int J Oral Maxillofac Implants   . 2009;24 Suppl:12-27. 

Systemic conditions and treatments as risks for implant therapy 

Michael M Bornstein1, Norbert Cionca, Andrea Mombelli 

https://pubmed.ncbi.nlm.nih.gov/19885432/

Results: For most conditions, no studies comparing patients with and without the condition in a controlled setting were found. For most systemic diseases there are only case reports or case series demonstrating that implant placement, integration, and function are possible in affected patients. For diabetes, heterogeneity of the material and the method of reporting data precluded a formal meta-analysis. No unequivocal tendency for subjects with diabetes to have higher failure rates emerged. The data from papers reporting on osteoporotic patients were also heterogeneous. The evidence for an association between osteoporosis and implant failure was low. Nevertheless, some reports now tend to focus on the medication used in osteoporotic patients, with oral bisphosphonates considered a potential risk factor for osteonecrosis of the jaws, rather than osteoporosis as a risk factor for implant success and survival on its own. 

Conclusions: The level of evidence indicative of absolute and relative contraindications for implant therapy due to systemic diseases is low. Studies comparing patients with and without the condition in a controlled setting are sparse. Especially for patients with manifest osteoporosis under an oral regime of bisphosphonates, prospective controlled studies are urgently needed. 

Int J Oral Maxillofac Implants  . 2009;24 Suppl:39-68. 

History of treated periodontitis and smoking as risks for implant therapy 

Lisa J A Heitz-Mayfield1, Guy Huynh-Ba 

https://pubmed.ncbi.nlm.nih.gov/19885434/

Conclusions: There is an increased risk of peri-implantitis in smokers compared with nonsmokers (reported odds ratios from 3.6 to 4.6). The combination of a history of treated periodontitis and smoking increases the risk of implant failure and peri-implant bone loss.