Guidelines

Attrition and implant research

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Appraisal of “Clinical and Radiographic Outcomes of Dental Implant Therapy”*  by Mark-Steven Howe

*(J Derks et al. 2015; Jan Derks et al. 2015; Derks, J. Schaller, D. Håkansson, J. Wennström, J.L. Tomasi, C. and Berglundh 2015)

implant astra

Introduction

The initial study protocol(Jan Derks et al. 2015) was created to evaluate patient-reported outcomes following implant-supported restorative therapy in a randomly selected patient sample taken from the Swedish Social Insurance Agency. Having selected the data set the research evolved into a further study on peri-implantitis and implant survival. This was registered with ClinicalTrials.gov (NCT01825772) in 2013.

The research was broken into two papers using the same data set:

  1. The primary research question was to report on the prevalence, extent, and severity of peri-implantitis in a large and randomly selected patient sample identified from the data register of the Swedish Social Insurance Agency.(Derks, J. Schaller, D. Håkansson, J. Wennström, J.L. Tomasi, C. and Berglundh 2015)
  2. The secondary research question was to report on the loss of dental implants assessed in a large and randomly selected patient sample. (J Derks et al. 2015)

Methods:

A sample of 4716 patients aged between 45 and 75 who had received implants in 2003 were randomly selected from the data registered with the Swedish Social Insurance Agency. From the 3827 respondents, patient files were collected on 2765 for analysis. From this group 900 randomly selected patient were invited to a clinical examination. Nine years following implant placement 596 of the 900 were examined by two periodontists, the clinical examination also included radiographs.

The patients were divided into two groups by age (45-54 and 65-74). Two examiners extracted from the files basic patient data that included information on diabetes, cardiovascular diseases, periodontitis at the time of implant therapy, smoking and recall frequency. Clinical evaluation included data on private or public dental clinical setting, general practitioner or registered specialist for the Swedish National Board of Health and Welfare. Additional data was collected on whether the operators were specialists or general practitioners. Implants were categorized according to brand, length (

A multiple logistic regression model was used to analyse the data.

Results

 Peri-implantitis:

  “In 98 (23.0%) of the 427 patients with baseline radiographs, no signs of peri-implant disease were detected. In addition,137 (32.0%) patients exhibited only peri-implant mucositis, while 192 (45.0%) presented with peri-implantitis. Moderate/severe peri-implantitis was observed in 62 (14.5%) patients.”

Peri-implantitis effecting implants by brand

Implant brand Odds Ratio 95% Confidence interval
Straumann Dental Implant System 1
Brånemark System Replace Select 3.77 1.60 to 8.87 0.002
Astra Tech 3.55 1.29 to 9.77 0.014
Remaining implants 5.56 1.70 to 18.24 0.005

Implant Survival:

Early Loss Late Loss Total Loss @ 8.9 years
Patients affected 4.4% 4.2% 7.6%
Implants Lost 1.4% 2.0% 3.0%
Implant brand Odds Ratio Odds Ratio
Straumann Dental Implant System 1 1
Brånemark System Replace Select 1.94 6.13
Astra Tech 2.10 5.23
Remaining implants 7.79 58.15

 Authors conclusions

Patients with periodontitis and with ≥4 implants, as well as implants of certain brands and prosthetic therapy delivered by general practitioners, exhibited higher odds ratios for moderate/severe peri-implantitis. Similarly, higher odds ratios were identified for implants installed in the mandible and with crown restoration margins positioned ≤1.5 mm from the crestal bone at baseline. It is suggested that peri-implantitis is a common condition and that several patient and implant-related factors influence the risk for moderate/severe peri-implantitis

In terms of implant loss, the present study reported on outcomes in implant dentistry assessed in a large and randomly selected patient sample representing effectiveness of the treatment procedures. Almost 8% of patients had lost ≥1 implants, and several patient and implant-related factors influencing early and late occurring loss were detected.

Comments

This was a well-conducted long-term retrospective cross-sectional study of a large randomly selected group of Swedish patients treated by both specialists and general practitioners. It is interesting to note it was registered on ClinicalTrials.gov when it is not technically a clinical trial. The registered protocol inclusion criteria was for 55 – 85 year olds but appears to have changed later to 45-54 and 65-74.

The only major problem with the results was the effect of attrition bias (Schulz & Grimes 2002). After initial randomisation 41% of the data was not available/excluded and from this reduced data set a further 900 samples were randomly selected of which 34% of the data was not collected. Since this data had been randomised this loss of data will most likely bias the results and affect the internal validity of the study, as it is unlikely to be all due to random causes. For example, patients who have had poorer outcomes or are less motivated may exclude themselves from the consent process or clinical examination phase. Though considerably more time consuming a clearer picture of the prevalence of peri-implantitis and survival rates could have been achieved if an ‘intention-to-treat principal’ had been followed. That is taking the whole randomised populations data into account when producing the results either via sensitivity analysis or imputation of the missing data.By taking out the data relating to patients who died, are sick or moved house (assume increased failures among the non-attenders) one can impute the total loss figure to be somewhere between 2.o% and 11.o%. Research has been carried out on analysing attrition bias and drop-out rate (Heneghan et al. 2007) to identify different group characteristics from those who responded to the authors questionnaires and clinical examination.

A couple of additional observations where the tight criteria for moderate/severe peri-implantitis (Bleeding on probing/suppuration and bone loss greater than 2mm) considering the 9-year time frame and pooling the moderate and severe results together. This may have been done to increase sample size. Since the majority of the implants were 10mm long and the mean bone loss on the implants with peri-implantitis was 29%, >3mm of bone loss would have given better resolution for clinically significant peri-implantitis. It is also a pity the results were not collected at 10-years to fall into place with other long-term survival/success studies.

In conclusion, the results of this well conducted study should be interpreted with caution due to the high attrition rates and therefore, even though the differences in odds ratios for infection/implant survival rates between the various brands are most likely accurate the results may be over-optimistic when compared to some systematic reviews (Srinivasan et al. 2016)

References

Derks, J. Schaller, D. Håkansson, J. Wennström, J.L. Tomasi, C. and Berglundh, J., 2015. Effectiveness of Implant Therapy Analyzed in a Swedish Population:Prevalence of Peri-implantitis. Journal of Dental Research, 94(3), pp.44–51.

Derks, J. et al., 2015. Effectiveness of Implant Therapy Analyzed in a Swedish Population : Early and Late Implant Loss. Journal of Dental Research, 94(3), pp.44–51.

Derks, J. et al., 2015. Patient-reported outcomes of dental implant therapy in a large randomly selected sample. Clinical Oral Implants Research, 26(5), pp.586–591.

Heneghan, C. et al., 2007. Assessing differential attrition in clinical trials : self-monitoring of oral anticoagulation and type II diabetes. , 12.

Schulz, K.F. & Grimes, D.A., 2002. Epidemiology series Sample size slippages in randomised trials : exclusions and the lost and wayward. , 359, pp.781–785.

Srinivasan, M. et al., 2016. Dental implants in the elderly population: a systematic review and meta-analysis. Clinical oral implants research. Available at: http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=reference&D=medp&NEWS=N&AN=27273468.

 

EBM Manifesto 2.0

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What is good for Evidence-Based Medicine is also good for Evidence-Based Dentistry. Siblings separated by the vagaries of history and politics.test-004

Prof Carl Henehgan gave an inspiring but also worrying presentation titled “Resuscitating poor quality research”.  One conclusion of the presentation was that throwing more money at healthcare will not solve the problems we are facing at present. The two areas that come up most in UK conversations are general practice, be that medical or dental and A+E. These are both ‘wicked’ environments and I would recommend all policy makers to read Rittel & Webber 1973 paper. A ‘wicked’ environment is unstable and ever changing, full of unique problems and solutions. Over the year’s policy makers have increasingly tried to tame these environments which by their very nature morph into a new set of problems.

In my practice, we are increasingly distracted from our patients/staff care by new layers of policy that bare no relation to the practice we work in. The two things that I would recommend are firstly that we accept what these environments are, and will always be, impossible to fully tame. Secondly we don’t need to waste large amounts of time and resource creating universal detailed policies  to deal with every possible adverse event. By the time one problem is ‘solved’ it is already redundant and has been overtaken by a new problem.

Practice is like a dance, at its best we are in constant state of flow, dealing with the ever-changing situation. This is based on deep knowledge, experience, care and compassion, not tick-boxes. We need the autonomy and trust of the policy-makers to balance the care of the individual with the care of the population. Trying to centrally ‘manage’ every aspect with a policy document or guideline creates an adversarial battle ground increasingly resistant to change or improvement.

Webber, M.M. & Rittle, H., 1973. Dilemmas in a General Theory of Planning *. Policy Sciences, 4 (December 1969), pp.155–169.

 

A SMOKERS GUIDE TO GOOD TEETH

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A SMOKERS GUIDE TO GOOD TEETH

Posted on January 2, 2017

After twenty-eight years as a dentist, I know that is if you really want to irritate a smoker then give them the usual advice about the perils of smoking and why they should quit. Perhaps they enjoy their smoking, the mouth-feel and scratch at the back of the throat, having something the hold or the social rituals involved.cigarettes-78001_1280

In this short article, I would like to try and spin the discussion the other way around. How can you basically keep most the benefits of smoking and keep your mouth and teeth healthy? How is that possible?

In January 2016, the Cochrane Library/University of Oxford published “Electronic cigarettes for smoking cessation (Review)”(Hartmann-Boyce 2016). Over the past twenty years, Cochrane has been instrumental on selecting the best medical evidence so help health-care professionals and patient maker better choices. Where this review differed from others is that it acknowledged that “none adequately addresses the sensory and behavioral aspects of smoking that smokers miss when they stop smoking (e.g. holding a cigarette in their hands, taking a puff, enjoyment of smoking, etc.). Electronic cigarettes (EC’s) may offer a way to overcome this limitation or smoking cessation.”

e-cigarette-electronic_cigarette-e-cigs-e-liquid-vaping-cloud_chasing-vaping_at_work-work_vaping_16348990255

So how can we improve the health of our teeth? Well, the major cause of damage to the mouth comes from the chemicals in the smoke rather than the nicotine, so it would seem obvious that if we can get the smoke out of smoking, improvements will follow. At present, however there is little evidence to support this since EC’s have only been around for about ten years and well conducted oral health studies need to run for a long time since the damage can take years to appear.

  • If you take the smoke out of smoking it  could halve the amount of stain on the teeth based on a paper published in 2005 by the University College London (Alkhatib et al. 2005) where “Twenty-eight percent of smokers reported having moderate and severe levels of tooth discolouration compared to 15% in non-smokers”
  • How about reducing the risk of shrinking gums and mobile teeth. According to a study from the University of Dunedin, New Zealand (Zeng et al. 2014) by the time the long-term smokers had reached thirty-eight years old they had 23% more damage to their gums than the non-smokers and the men had more gum damage than the women.
  • What about keeping hold of our teeth, especially the upper teeth. To get an idea of losing teeth we have to look at some very large long term studies started in 1994 (Dietrich et al. 2015). This is tricky since it starts to showup after the age of fifty,  and then in the next ten years the risk goes up by 30% for men smoking more than fifteen cigarettes a day.
  • If you have had dental implants remember that smoking around 15 regular cigarettes/day can slightly more than double the risk of implant loss at 5-years for similar reasons to the problems with gum disease (Chrcanovic 2015).
  • And finally mouth cancer. Now before anyone panics, this is very rare so a 1.4 to 26-time increase in risk compared to a nonsmoker is still a small risk (Radoï & Luce 2013). The big variation is complicated by the small number of cases, location, and alcohol consumption. If caught early it’s one of the easiest cancers to treat but if left to develop has a poor survival rate of 50% at five-years.

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So, back to the Cochrane review. Yes, we need more studies on how safe and effective EC’s really are in the long run. The review showed that using an “EC containing nicotine increased the chances of stopping smoking in the long term compared to using an EC without nicotine. We could not determine if EC was better than a nicotine patch in helping people stop smoking.” Therefore balancing the risk and the benefits, if you need the nicotine then at least consider an electronic cigarette as a first move and then reduce the nicotine if you are going to quit altogether. Good Luck.

References:

Alkhatib, M.N., Holt, R.D. & Bedi, R., 2005. Smoking and tooth discolouration: findings from a national cross-sectional study. BMC public health, 5, p.27. Available at: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1079878&tool=pmcentrez&rendertype=abstract.

Chrcanovic, A., 2015. Smoking and dental implants: A systematic review and meta-analysis. J Dent., 5, pp.487–98.

Dietrich, T. et al., 2015. Smoking, Smoking Cessation, and Risk of Tooth Loss: The EPIC-Potsdam Study. Journal of Dental Research, 94(10), pp.1369–1375. Available at: http://jdr.sagepub.com/cgi/doi/10.1177/0022034515598961.

Hartmann-Boyce, 2016. Electronic cigarettes for smoking cessation (Review). Cochrane database of systematic reviews (Online), 0(9), p.0. Available at: http://www.embase.com/search/results?subaction=viewrecord&from=export&id=L608013248%5Cnhttp://findit.library.jhu.edu/resolve?sid=EMBASE&issn=15320650&id=doi:&atitle=Electronic+cigarettes+for+smoking+cessation&stitle=Am.+Fam.+Phys.&title=American+Family+Ph.

Radoï, L. & Luce, D., 2013. A review of risk factors for oral cavity cancer: The importance of a standardized case definition. Community Dentistry and Oral Epidemiology, 41(2), pp.97–109.

Zeng, J. et al., 2014. Reexamining the Association Between Smoking and Periodontitis in the Dunedin Study With an Enhanced Analytical Approach. Journal of Periodontology, 85(10), pp.1390–1397. Available at: http://dx.doi.org/10.1902/jop.2014.130577.