Tuesday, August 12, 2014

Why Most Research Findings Are False

Dr. John P. A. Ioannidis is a Professor of Medicine, Health Research and Policy at Stanford University.  He holds the C.F. Rehnborg Chair in Disease Prevention and is the director of the Stanford Prevention Research Center (SPRC) at Stanford University School of Medicine.  He is a professor of Statistics and one of two directors of the Meta-Research Innovation Center at Stanford (METRICS).

In an article published in 2005, titled "Why Most Research Findings Are False", Dr. Ioannidis explains the increasing concern that most current published research findings are false.  There are many factors that play into this problem such as research design, definitions, outcomes, financial interests, prejudice, and the "chase for statistical significance".  In fact, Dr. Ioannidis states that for many current scientific fields, published research findings may be little more than "accurate measures of the prevailing bias".

Dr. Ioannidis and other methodologists, have pointed out that the high rate of non-replication of research discoveries is based on a convenient, yet ill-founded strategy of claiming conclusive research results after a single study where statistical significance is claimed based on the p-value of <0 .05.="" p="">

Dr Ioannidis is known for defining the proteus phenomenon, which is the greater tendency for the early repeat studies done to contradict the original study.  The proteus phenomenon was named for the Greek God Proteus, who had the ability to change form.

Research findings are less likely to be true in research studies with:
1. Smaller sample size
2. Smaller the effect size
3. Greater the number and lesser the selection of tested relationships
4. Greater the flexibility in designs, definitions, outcomes and analytical modes
5. Greater the financial and other interests and prejudices
6. Hotter the scientific field (more teams interested in studying a field)

While it is impossible to know with 100% certainty what the truth is in any research question, Dr. Ioannidis makes some recommendations on how we can improve the scientific research.

1. Seek better powered evidence (large studies or low-bias meta analysis) with acknowledgment and avoidance of bias.
2. Find ways to evaluate the all the evidence generated by multiple teams studying the same topic.  Find ways to develop and follow protocols as done in randomized clinical trials.
3. Rather than focusing on p-value for statistical significance, improve the understanding of the range of R values - pre-study odds.  This helps us understand the chances that we are testing a true, rather than an un-true relationship.

Dr. Ioannidis is not the only one concerned about the effect of bias in the research.


Pannuchi and Wilkens have said "Bias can occur in the planning, data collection, analysis, and publication phases of research. Understanding research bias allows readers to critically and independently review the scientific literature and avoid treatments which are suboptimal or potentially harmful. A thorough understanding of bias and how it affects study results is essential for the practice of evidence-based medicine."  They go on to discuss how bias can affect a study before, during and after the research is complete.

An article in Radiology by Gregory Sica MD, MPH reviews types of study design, types of selection bias, types observational bias, and suggests some ways to reduce bias in research.

Mullane and Williams ask if bias in biomedical research has become the rule rather than the expectation.  They indicate that bias in research is amplified by competition and difficulty getting funding, pressures for maintaining laboratories and staff, desire for career advancement, and monetization of science for personal gain.  They also mention the increasing body of research publications that cannot be repeated or require corrections or retractions.

Other Resources
Bias in Research (Sandra Burge PhD) - an online learning module from UTHSC San Antonio
Continuum Between Fraud and "Sloppy Science" - Scientific American

Dr. Ioannidis will be the keynote speaker at the Nowzari Symposium on Friday, Nov. 7th 2014 in Beverly Hills, CA.  See you there!


Source:

1.  Ioannidis JPA (2005) Why Most Published Research Findings Are False. PLoS Med 2(8): e124. doi:10.1371/journal.pmed.0020124
2. Pannuchi, C Wilkens, E Identifying and Avoiding Bias In Research. Plast Reconstr Surg. Aug 2010; 126(2):619-625.
3. Sica, G Bias In Research Studies. Radiology. Mar 2006; 238:3.

4. Mullane, Williams. Bias in Research: The Rule Rather Than The Exception. Editors Update. Sep 2013. Issue 40.
5. Moonesinghe R, Khoury MJ, Janssens ACJW (2007) Most Published Research Findings Are False—But a Little Replication Goes a Long Way. PLoS Med 4(2): e28. doi:10.1371/journal.pmed.0040028

Monday, July 7, 2014

Saving a Tooth with Intentional Replantation

Previous posts have discussed the often overlooked surgical option of intentional replantation.  The following case is an example of 3.5 yr success of intentional replantation of a Md second molar.

#31 Prior RCT with Chronic Apical Abscess - with recurring sinus tract.  Radiograph shows the overfill on all canals and large periapical/ furcal lesion.
CBCT shows the extent of the bone loss.

CBCT also shows the root anatomy and the buccal/lingual bone in tact.
At this point, retreatment or surgery are the options to preserve the tooth. With a crown, not needing to be replaced, a long post and overfilled gutta percha - which can be difficult to retrieve, we considered a surgical approach. Since this is a second molar, the buccal bone is too thick to allow for conventional surgical approach (apicoectomy).  After discussing risks of intentional replantation, pt elected to preserve tooth using intentional replantation. 

Tooth extracted atraumatically.  (Crown came off during extraction.)

Apico & retrofill completed chairside
Tooth replanted.
Note the bone levels around the tooth. They are identical to the pre-op bone levels.  Intentional replantation has preserved the natural tooth AND the periodontium.

Monday, June 30, 2014

Internal Bleaching of VITAL Teeth



With the recent advances in regenerative endodontics, we have come to see the pulpal tissue in a new light.  This has encouraged us to treat healthy pulpal tissue in ways that would seem counter-intuitive.  For example, in the treatment of a decayed tooth, with immature roots - when the pulpal tissue is completely healthy, we may try an MTA pulpotomy on a permanent tooth, and give the tooth a chance to finish its development. We are finding new ways to perform apexogenesis procedures. The apexification procedure is becoming a thing of the past. In fact, I haven't performed an apexification in several years.

This new approach to the pulpal tissue has brought up a new questions.  In a mature tooth, with calcific metamorphosis causing discoloration, is it really necessary to perform a root canal before internal bleaching?  Conventional wisdom would say yes.  But our understanding and respect for the pulpal tissue and its capacity to repair itself has changed my view on this procedure.

First off, teeth with calcific metamorphosis are often misdiagnosed as necrotic because they do not respond to thermal pulp testing.  Electric pulp testing (EPT) is required to determine vitality on these teeth.  If these discolored teeth are determined to have vital, normal pulps and periapices - why not perform internal bleaching without RCT?

The following case is an example of this procedure.

History of trauma to #8 with gradual discoloration
Close up of the color difference
Radiograph shows pulpal obliteration - complete calcification
Normal endo access with stain removal under microscope without entering canal.  Glass ionomer barrier placed at the CEJ and Opalescence Endo placed in pulp chamber. Access closed with Cavit and bleach left for 1 week. Fresh bleach reapplied for a second week.

Access filling placed.
Before & After
With no exposure of the canal system on a vital tooth, internal bleaching can be performed WITHOUT prior endodontic therapy.

Friday, June 13, 2014

Insurance Companies Respond to Delta Dental of AZ's Recent Changes

The dental insurance world in AZ is a buzz with the recent changes regarding Delta Dental of AZ.  These changes will force providers into the PPO network, to become exclusive Delta providers or terminate their relationship with Delta Dental of AZ.


There has been contact made with the AZ Attorney General's office regarding these concerns by other dental insurance providers.


Here are a few of the recent letters we have seen regarding their response to Delta. While being an exclusive provider for Delta is not a new concept, it is obvious that other insurance companies see that as anticompetitive and questioning it's legality.





Tuesday, May 6, 2014

Delta Dental of Arizona Cutting Reimbursements to Arizona Dentists

The Delta Dental of AZ website says, "...dentists are valuable partners in providing quality oral health care and Delta Dental is striving to find the right balance between the dentists, the companies and our enrollees to remain the leading dental benefits provider in our state."  The latest move in striving to find this balance is to reduce the reimbursements to Premier Provider dentists by forcing them into the lower paying PPO dental plan.  In a recent letter from Delta Dental of AZ, I was informed that the Premier Plan, of which I am a provider, is being retired and I have three options:

1. Accept the Delta Dental PPO contract fees
2. Become an exclusive provider - accepting ONLY Delta Dental insurance
3. Terminate my provider relationship with Delta Dental


In order to evaluate the decision of staying with Delta Dental, I decided to look to FairHealthConsumer.org to find out what a "fair" price is for endodontic procedures in my region.

Fair Health is a national, independent, not-for-profit corporation whose mission is to bring transparency to healthcare costs and health insurance information through comprehensive data products and consumer resources. FAIR Health uses its database of billions of billed medical and dental services to power a free website that enables consumers to estimate and plan their medical and dental expenditures.

As a consumer, this is what FAIR health says should be charged for endodontic treatment in my zip code.  If I have no insurance, this is what I should expect to pay.


According to FAIR health, the reasonable cost for a molar root canal in 85206 zip code is $1203.00


According to FAIR health, a typical dental insurance policy should expect the insurance to cover $601.50 of the root canal and I should expect an out of pocket expense of $601.50.


Now looking at the proposed reimbursement for an endodontist doing these three procedures, Delta Dental PPO wants me to reimburse at the following rates.
Molar RCT (D3330) 36% below the FAIR price
Bicuspid RCT (D3320) 41% below the FAIR price
Anterior RCT (D3310) 44% below the FAIR price
At SSE our current fees are BELOW the FAIR health fees for our area.
As a Premier provider with Delta Dental we are reimbursed at:
Molar RCT (D3330) 16% below the SSE Fee
Bicuspid RCT (D3320) 23% below the SSE Fee
Anterior RCT (D3310) 30% below the SSE Fee
If we become a PPO provider for Delta Dental, we will be reimbursed at:
Molar RCT (D3330) 31% below the SSE Fee
Bicuspid RCT (D3320) 42% below the SSE Fee
Anterior RCT (D3310) 48% below the SSE Fee
Looking at those reimbursements, Delta Dental PPO would become the worst reimbursing insurance company that we work with. As a business owner, at what point does it become non-profitable to see Delta patients? How does any business function at a 30-50% discount?  The obvious business answer is that you have to make it up the difference in volume which typically means a decrease in the quality of service.  (does corporate dentistry sound familiar?)


If you are a Premier provider, you may want to look at the numbers carefully.  If you don't contact Delta by written notice, you will automatically become a PPO provider on July 1, 2014!


If you are a general dentist, the Delta PPO want to reimburse you at the following rates:

Molar RCT (D3330) 54% of the FAIR price
Bicuspid RCT (D3320) 52% of the FAIR price
Anterior RCT (D3310) 51% of the FAIR price



As a company, who was initially founded by dentists in California, Washington and Oregon and has become one of the largest dental networks in the country, this move to cut reimbursements by forcing its premier providers into the PPO network does not seem to support the dentist.


If you are a dentist in another state that has been affected by Delta Dental cuts, what has been your experience?

If you are an Arizona dentist, what are you planning to do and how do you think it will affect your practice?



Some other interesting links regarding this pattern of Delta Dental to cut reimbursements to Dentists.

DentalTown Discussion regarding Delta Dental of Washington cutting reimbursements






Tuesday, April 29, 2014

CBCT in Endodontics to Treat Difficult Anatomy & Preserve Teeth

A patient recently came to SSE for a second opinion. She had a root canal on #21 just a month earlier by an endodontist.  After the root canal, she continued to have pain and the root canal was retreated shortly thereafter.  The patient was then sent to a periodontist who recommended extraction and placement of an implant.  Aware of endodontic surgical options, her general dentist recommended she come for an additional evaluation.  The patient was highly motivated to save her natural tooth.




Our exam found #21 normal to percussion, normal probings and swelling on the buccal.  An additional canal was suspected, so CBCT was taken for further review.




CBCT clearly shows an additional lingual canal.  CBCT mapping allowed us to determine where the canal would be located and confirm that it had its own apical foramen.  With greater understanding of the canal anatomy, available only through 3D imaging, we recommended non-surgical retreatment to address the missed lingual canal.


With the aid of the microscope, we were able to locate and treat the missed lingual canal.



Because a canal was missed, retreatment (rather than apicoectomy) was the treatment recommended. Prognosis is good. Proper endodontic therapy will save this patient time and money.  Fortunately, this patient's dentist suggested a second consultation for endodontic surgery rather than the extraction and implant placement. Endodontists are specialist is saving teeth.

Thursday, April 10, 2014

Teeth & Implants: The Rest of the Story

At the upcoming Inner Space Seminar on Friday, April 11th, 2014, Dr. Hessam Nowzari will present a balanced approach to the discussion regarding teeth and implants.

  • What does the research show regarding the long term success of restored teeth and dental implants?
  • What effect does corporate marketing have on the dental educational system and dentistry as a whole?
  • What is the quality of research that is being published in our dental journals and what effect does that have on our profession?
  • How do we evaluate the quality of research to help us make important clinical decisions for our patients?
  • What are the important considerations when deciding to retain a tooth or replace with an implant?

As a periodontist, implant surgeon, former director of graduate periodontics at USC, and world renowned lecturer and researcher, he is uniquely qualified to lead this discussion in a responsible, scientific and unbiased manner. 



UPDATE:  This morning we are inviting all of the participants of the seminar, to share their thoughts and impressions of the presentation throughout the presentation.

Monday, April 7, 2014

Why Teeth and Implants Are Not Alternative Treatments

Sometimes patients ask why they should save a tooth with a root canal and crown when they can just place an implant.  A recent survey by Azarpazhooh et. al. demonstrated a declining pattern of preference for root canal therapy (RCT) in favor of implant supported crowns (ISC) among general dentists, periodontists, prosthodontists and oral surgeons as opposed to endodontists.  This declining pattern showed a significantly higher preference for ISC over RCT retreatment.

While dental implants are an important treatment option for our edentulous patients, implants, cannot replace the periodontium (tooth, ligament, gingival fibers, alveolar bone) that belong to the tooth.  Extraction of a tooth removes the genotype which produces the phenotype that gives the tooth its characteristics.  Most, if not all, of the long term challenges with implants such as crestal bone loss, loss of gingival architecture, occlusal trauma and perioimplantitis are due to the lack of periodontium.

Gastrulation of the Diploblast: The germ layers form as the
ectoderm (orange) move inward forming the
endoderm (red). Source
Can you remember that dental embryology class?  Remember the endoderm, ectoderm and mesoderm?  While you may not have thought about these tissues for many years, understanding the difference between teeth and implants goes back to that first semester of dental school.
All human tissues form from one of these three embryonic tissue layers (endoderm, mesoderm, ectoderm).
The tooth is formed from ectodermal tissue and it's close developmental association with the mesenchymal (mesodermal) tissue.

The tooth bud is an invagination of the ectodermal tissue into the mesodermal tissue. Neural crest cells (ectodermal cells) that blend with the mesodermal cells are called ectomesenchymal cells.  The interaction of the ectoderm and ectomesenchymal cells form the enamel organ which forms the tooth.


So as the tooth develops through the bud, cap, bell stages, the enamel organ will form the enamel, the dental papilla will form the dentin and pulp tissue and the dental sac will form all the supporting structures. These supporting structures (periodontium) include cementum, periodontal ligament and alveolar bone.  The alveolar bone, including the lamina dura are derived from osteoblasts formed from ectomesenchymal cells.



The tooth develops as an invagination of the ectoderm
into the mesodermal tissue.  This makes the periodontium
(tooth and its surrounding supportive structures -
gingiva, ligament, alveolar bone) of ectodermal origin.
Once the tooth is lost, these tissues are irreplaceable.

So the tooth, and its supporting structures are derived from ectodermal tissue and ectomesenchymal tissue.  In other words, the periodontium BELONGS to the tooth.


So why does this matter?  It matters because when a tooth is extracted, the periodontium is lost.  The periodontium is what makes a tooth look, function and feel like a tooth.


The maxillary or mandibular bone is derived from mesodermal tissue.  When the dental implant is placed into the jaw bone, it is placed into bone derived from the mesodermal tissue.  That bone has different quality and function from the bone associated with the periodontium.
That is why the dental implant does not feel, look or function "just like a tooth".  They are not the same. This important point should not be forgotten.


Come and learn more about teeth and implants at our upcoming Inner Space Seminar - This Friday, April 11th, 2014 - featuring Dr. Hessam Nowzari.


Thursday, February 13, 2014

Resolution of Odontogenic Sinusitis after RCT Retreatment


The use of CBCT in endodontics is helpful in the diagnosis and treatment of sinusitis of odontogenic origin.  The following case demonstrates how proper endodontic treatment will resolve an asymptomatic sinusitis of odontogenic origin.

Pt reports swelling, throbbing, percussion pain but reports no sinus symptoms of congestion, drainage, restricted airflow through the nose or sinus headaches.

CBCT take for further evaluation of prior RCT.  CBCT shows missed MB#2, thickened sinus membrane, large pa lesion on MB with elevated sinus floor (halo effect). DX: Prior RCT with acute apical abscess & odontogenis sinusitis.
Missed MB#2 canal seen in axial view.


Slight halo effect
RCT Retx completed.
7 Month Recall

7 month recall.  Pt is asymptomatic. CBCT shows resolution of the previously thickened sinus membrane, healing of periapical lesion, previous elevation of the sinus floor has resolved.  All signs and symptoms have resolved.



 

Wednesday, February 5, 2014

Pulpal Regeneration on a Carious, Immature, Necrotic Molar

Most pulpal regeneration cases are done on traumatically injured anterior teeth.  The following case is a pulpal regeneration on an immature, necrotic tooth #19 due to coronal decay.


This regenerative procedure was done in a single visit, NaOCl irrigation, MTA barriers, flowable composite over MTA and Luxacore resin buildup.  Proper coronal coverage will help preserve this tooth until a permanent crown can be made. No further endodontic therapy is needed on this tooth.