How You See It and How You Don’t: How the Principles of Human Perception Affect CBCT Interpretation

(a) Try to find the dog in this image. (b) Can you make out any forms from the splotches in this image? (c) Though it may be hard to tell, both of the smaller rectangles are the same shade of gray. (d) This image appears to be a gradient gray bar over a similar gradient background. However, if you cover the background you will see that the bar is a uniform shade of gray.

Everyone loves a good optical illusion. The world of social media was simultaneously thrilled and frustrated by the apparently color-changing dress that appeared in 2015 (discussed here, along with 11 other optical illusions). We enjoy optical illusions when they present as a fun trick to discuss with our friends. You may enjoy them less when they’re hiding in your patient’s CBCT scans, however.

“When digital radiography came out 20 years ago,” Dr John Khademi explains, “misinterpretation was rampant. Lots of fillings and crowns were inappropriately re-done by dentists who misinterpreted artifactual findings as recurrent decay. They took out the filling or cut off the crown and, lo-and-behold—no decay.”

“The problem with CBCT can be likened to the chicken and the egg,” he continues. “With periapical radiography, we all went to dental school and learned about how radiographs are made and how to interpret them: what decay looked like, crowns, fillings, etcetera. As specialists we went to endodontic school with people who had experience and we could interpret the radiography and get feedback from those with expertise: ‘This subtle finding means x, that finding means y.’ There was domain expertise and skill-set transfer. But CBCT was deployed into private practice completely devoid of any academic understanding of the image-generation process. There was an illusion of domain expertise as the medium looked familiar, but it wasn’t, leading to interpretive errors.”

Without that academic background in CBCT, clinicians are working backward to develop their expertise. Dr Khademi’s new book, Advanced CBCT for Endodontics: Technical Considerations, Perception, and Decision-Making, is a step toward filling the gaps in the industry’s current knowledge regarding CBCT interpretation. In it, he confronts and explains how the principles of human perception affect how we interpret CBCT imagery, much like how it affects what we see in those tricky optical illusions passed around via social media.

“Endodontists bring to the interpretive process a bias for interpretation that is influenced by other findings in the imaging,” Dr Khademi explains. “[In the figure to the right], the poorly done endodontics hits the endodontist immediately and biases the interpretation of the periapical area, increasing the chances that he or she will call an abnormal finding. This detection and recognition happens very quickly without effort and cannot be stopped. The clinician needs to then engage higher thinking and consider, ‘Are there any other explanations for these observations?’ The endodontist must recognize that all of the expertise he or she is bringing to the interpretive process is a double-edged sword.”

Use this attentional template to find the form hiding in image b at the top of this article.

The familiarity endodontists have with certain findings form attentional templates, similar to how we recognize familiar shapes or patterns in optical illusions. “We have an attentional template for recurrent decay underneath a crown from film radiography,” Dr Khademi says. “This attentional template hits us very fast with the perceptual process, and we mistake this familiarity and the speed with which we recognize this pattern for accuracy. However, this isn’t the film domain; it’s the digital domain, and a host of new artifactual imaging findings are possible.”

In the image to the right, we see what looks like recurrent decay and/or open margins. However, what is seen is actually an image-processing artifact called ringing artifact. This artifact mimics the attentional template for recurrent decay and open margins. The images below show this particular artifact simulated by software. Without knowledge of image processing and related artifacts specific to CBCT, the endodontist cannot differentiate between what is real and what is illusion, increasing the opportunity for inaccurate diagnoses.

How Do We Improve?

Clinicians must develop a new internal database not biased by the attentional templates developed through periapical radiography because the differences between the mediums mandate that much of that knowledge does not translate, and any attempt to make it translate may jeopardize success. Dr Khademi lays out the steps for building this knowledge:

“What endodontists must develop in terms of an internal database is the large number of artifactual findings that have no analog in PA radiography and can mimic pathologic findings, the very wide range of normal periapical findings at CBCT compared to projection radiography, and better language to describe imaging findings in a way that highlights inferences and uncertainty.”

All of these topics are covered in Dr Khademi’s book. However, he also emphasizes that endodontists must be open to feedback as well. “In private practice, we are generally alone and, because we aren’t the ones to extract teeth later, we don’t get feedback on our interpretive errors.”

In his book, Dr Khademi shares an example of a case (featured above) that he managed in 2010 right after installing a CS-9000 imager in his practice. The periapical projection radiography showed radiolucent findings possibly encompassing two or three roots and likely short root fillings of the mesiobuccal root, among other findings. The CBCT study showed radiolucent changes surrounding the palatal root, so Dr Khademi recommended extraction and replacement with an implant and referred the patient to a periodontist. The periodontist called back and said, “You may want to treat the necrotic lateral incisor.” While this particular case demonstrates the issue of satisfaction of search—the idea that once a meaningful interpretation is found, we stop looking—it also illustrates the importance of feedback.

“For us to experience failure we need to know that we have failed, and that requires feedback, Dr Khademi explains. “Here, in reference to my own interpretive failure on the necrotic lateral incisor, I would have never known that I had missed that finding had the periodontist not given me that feedback. Lacking feedback, there is some evidence that learning simply will not occur.”

When reading Dr Khademi’s book for the first time, some clinicians may find unsolicited feedback when they recognize artifacts explained in the text as findings they may have seen in their own patients’ imaging. However, as with the famous dress that some of us incorrectly saw as white and gold, the best part of finding out when you’re wrong is learning how to be right.


John A. Khademi, DDS, MS, is an adjunct assistant professor of endodontics at Saint Louis University. He received his dental degree from the University of California San Francisco and his certificate in endodontics and MS in digital imaging from the University of Iowa. He previously wrote software for laboratory automation, instrument control, and digital imaging. He lectures internationally about CBCT, clinical trial design, outcomes, and conventional endodontic techniques. As a Radiological Society of North America (RSNA) member for over 25 years, his background in medical radiology allows him a perspective shared by very few dental professionals. He maintains a private practice limited to endodontics in Durango, Colorado.

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Quintessence Roundup: May


Quintessence 2017 Catalog

New Titles in Books


The Art and Science of Contemporary Surgical Endodontics
(Book/DVD set)

Edited by Mahmoud Torabinejad and Richard Rubinstein

This book begins with a concise review of the basic science of tissues and then moves into diagnosis, treatment planning, and surgical procedures in endodontics, with an emphasis on the use of enhanced magnification, ultrasonic tips, microinstruments, newer root-end filling materials, and CBCT. Chapters on the maxillary sinus and its relation to surgical endodontics, soft and hard tissue healing, and adjunctive surgical procedures and considerations such as management of procedural accidents, resorption, root amputation, hemisection, replantation, transplantation, crown lengthening, grafting materials, and pharmacology are followed by an assessment of the outcomes of surgical endodontics based on current evidence. The accompanying DVDs present valuable videos demonstrating many of the procedures. These features provide the reader with a textbook that is concise, current, and easy to follow in an interactive manner. Written by a team of leading authorities and richly illustrated, this new compendium of state-of-the-art knowledge and protocols is essential reading for practicing endodontists and residents alike.

336 pp; 685 illus; ISBN 978-0-86715-731-4 (B7314); Now available! US $198.00

Surgical Endodontics: An Inherently Conservative Approach

Advanced CBCT for Endodontics:

Technical Considerations, Perception, and Decision-Making

John A. Khademi, with contributions by Gary B. Carr, Richard S. Schwartz, and Michael Trudeau

This book encourages endodontists to develop a sound technical and theoretical understanding of CBCT. The authors compare the capabilities of modern CBCT imaging with traditional radiography and also present vital information about image interpretation and perception to increase competence and confidence in CBCT interpretation and minimize overdiagnosis and subsequent overtreatment.

352 pp; 688 illus; ISBN 978-0-86715-720-8 (B7208); Special preorder price! US $118

 

New Issues in Journals


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Featured article: Mandibular Regional Anatomical Landmarks and Clinical Implications for Ridge Augmentation
Istvan A. Urbán, Alberto Monje, Hom-Lay Wang, Jaime Lozada, Gabor Gerber, and Gabor Baksa

A Novel Approach to Bone Reconstruction: The Wafer Technique
Mauro Merli, Marco Moscatelli, Giorgia Mariotti, Alessandro Motroni, Annalisa Mazzoni, Simona Mazzoni, Lorenzo Breschi, and Michele Nieri

Survival Rates and Bone and Soft Tissue Level Changes Around One-Piece Dental Implants Placed with a Flapless or Flap Protocol: 8.5-Year Results
Stuart J. Froum and Ismael Khouly

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Bone Quality and Quantity and Dental Implant Failure: A Systematic Review and Meta-analysis
Bruno Ramos Chrcanovic, Tomas Albrektsson, and Ann Wennerberg

CAD/CAM Ceramic Overlays to Restore Reduced Vertical Dimension of Occlusion Resulting from Worn Dentitions: A Case History Report
Jiang Ting, Han Shuhui, and Hongqiang

Support Ratio Between Abutment and Soft Tissue Under Overdentures: A Comparison Between Use of Two and Four Abutments
Manami Abe, Tsung-Chieh Yang, Yoshionobu Maeda, Takanori Ando, and Masahiro Wada

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Featured Article: Are “Human Factors” the Primary Cause of Complications in the Field of Implant Dentistry?
Franck Renouard, René Amalberti, and Erell Renouard

Thematic Abstract Review: Immediate Implant Placement and Restoration: An Update
Guy Huynh-Ba

Extraoral Implants for Anchoring Facial Prostheses: Evaluation of Success and Survival Rates in Three Anatomical Regions
Heitor Batista dos Reis, Joaquim Augusto Piras de Oliveira, Vanessa Arias Pecorari, Shiva Raoufi, Márcio Abrahão, and Luciano Lauria Dib

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Interprofessional Education and Collaboration as an Approach to Overcoming Perceived Barriers in Improving Oral Health
Lorinda Coan and Amanda R. Reddington

Quality Resources for Clinical Decision Making: Part 4. Understanding the Flossing Controversy
JoAnn R. Gurenlian and Jane L. Forrest

Critical Thinking in Action: Consideration of Alternative Hypotheses
Donald M. Brunette

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A Retrospective Study on Possible Predictive Factors for Long-term Temporomandibular Joint Degeneration and Impaired Mobility in Juvenile Arthritis Patients
Stanimira I. Kalaykova, Adriaan T. Klitsie, Corine M. Visscher, Machiel Naeije, and Frank Lobbezoo

Prevalence of Temporomandibular Disorders in the Northern Finland Birth Cohort 1966
Päivi Jussila, Heikki Kiviahde, Ritva Näpänkangas, Jari Päkkilä, Paula Pesonen, Kirsi Sipilä, Pertti Pirttiniemi, and Aune Raustia

A Rare Case of Misdiagnosed Silent Lung Cancer with Solitary Metastasis to the Temporomandibular Joint Condyle
Luca Guarda-Nardini, Edoardo Stellini, Adolfo Di Fiore, and Daniele Manfredini

Dental Meetings Quintessence Will Attend in May


ACOMS and CAOMS Joint Scientific Conference and Exhibition: Booth #11
hosted by the American College of Oral and Maxillofacial Surgeons and the Canadian Association of Oral and Maxillofacial Surgeons, May 3–5 in Vancouver, British Columbia

CDA South: The Art and Science of Dentistry: Booth #1327
hosted by the California Dental Association, May 4–6 in Anaheim, California

Oral Reconstruction Foundation 2017 Global Symposium
hosted by the Oral Reconstruction Foundation, May 4–6 in Miami, Florida

AAOP 41st Scientific Meeting: The Evolving World of Orofacial Pain: Booth #109
hosted by the American Academy of Orofacial Pain, May 4–7 in Scottsdale, Arizona

State of the Art: Facial Reconstruction and Transplantation
hosted by AO North America, May 19–21 in New York, New York

AAPD 2017: Booth #236
hosted by the American Academy of Pediatric Dentistry, May 25–28 in National Harbor, Maryland

47th Journées dentaires internationales du Québec
hosted by the Ordre des dentistes du Québec, May 29–30 in Montreal, Quebec

Upcoming Quintessence Symposia


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Surgical Endodontics: An Inherently Conservative Approach

Cleared specimens of maxillary first molar mesiobuccal roots showing the complex canal anatomy and endodontic treatment task. (Courtesy of Dr Craig Barrington, Waxahachie, Texas.)

Dr Noah Chivian first argued for the conservative nature of surgical endodontics in a 1969 article in the Journal of the New Jersey Dental Association titled “Surgical Endodontics, A Conservative Approach”; it is now 2017, and the industry continues to have this debate.

Conservative is commonly defined as ‘disposed to preserving existing conditions,'” Dr Chivian explains, reflecting on his 1969 article. “At that time, popular dental semantics referred to the two courses of endodontic action as conservative and surgical. This implies that the surgical approach is radical and the nonsurgical approach is conservative. However, both of these methods try to ‘preserve existing conditions’ by retaining teeth, and therefore both must be considered conservative. In fact, modern endodontic surgery may be more conservative than disassembly, retreatment, and re-restoration.”

Two acclaimed endodontists, Mahmoud Torabinejad, DDS, MSD, PhD, and Richard Rubinstein, DDS, MS, hope to settle this argument for good with their new book, The Art and Science of Contemporary Surgical Endodontics.

“Endodontic surgery is inherently conservative because it is an alternative to tooth extraction, a radical and aggressive treatment that results in the loss of an organ, in many cases,” Dr Torabinejad states.

“The current paradigm being taught in most residencies is that if an endodontic treatment fails, retreatment must be performed or attempted before endodontic surgery can be considered,” Dr Rubinstein says. “But in complex cases involving posts and cores, sometimes the disassembly required for retreatment compromises too much tooth structure, and extraction becomes inevitable. This is the opposite of conservative.”

(left) Hess model of a mandibular molar showing anatomical complexities throughout the root canal system. (right) Hess model of a mandibular premolar showing anatomical complexities in the apical terminus.

Modern Advances in Surgical Endodontics: Possibility Becomes Predictability

According to Dr Rubinstein, there is a difference between possibility and predictability. And the point when endodontic surgery became more predictable—and therefore more conservative—than retreatment for complex cases came when modern technology, namely cone beam computed technology (CBCT) and surgical operating microscopes (SOMs), enabled endodontic surgeons to better identify and more accurately treat complex tooth morphologies.

The incidence of anatomical complexities in root canals is well documented. CBCT technology enables clinicians to identify these complexities and plan for them. “Failure to address these complexities,” Dr Rubinstein asserts, “leaves the tooth vulnerable to reinfection. Significant pulpal anatomy such as accessory canals and isthmi has to be considered when performing both surgical and nonsurgical endodontic treatment.”

Doctor and assistant at the SOM.

The SOM made it possible to manage those complexities during surgery. Dr Rubinstein was one of a handful of endodontists who first began experimenting with the SOM for apical surgery: “We thought, ‘If you can see something better, you can treat it better,’ and the results were overwhelming. Cases that seemed impossible before became easy and exciting to operate on, and teeth that might otherwise have been extracted now had a predictable chance for retention.”

(a) 3D rendering of the mandibular left first premolar showing the periapical lesion and its relationship to the mental bundle. (b and c) Axial and coronal 3D renderings showing the untreated lingual canal (blue and white arrows), the extent of the lesion buccolingually, and the relationship of the root to the buccal and lingual cortical plates (c). (d) Clinical image after flap reflection and identification of the mental bundle (black arrow). (e) Because of the close proximity of the root to the mental bundle (white arrow), a piezoelectric surgery insert OT5 (Mectron) was used for the osteotomy. (f) Root resection performed with OT7S-3 insert (Mectron). (g) Resected apical third with the OT7S-3 insert. (h) Clinical image demonstrating the untreated lingual canal (white arrow) and isthmus. (i) Application of EndoSequence BC Sealer (Brasseler USA) into the apical preparation prior to placement of the Root Repair Material (RRM) (Brasseler USA). (j) RRM material filling in the buccal and lingual canals. (k) Postoperative radiograph demonstrating the RRM filling in the lingual canal (white arrow) and buccal canal (blue arrow).

Changing the Paradigm

There are many reasons why endodontic surgery is not as popular as nonsurgical endodontics or implant dentistry, but the biggest obstacle to wider implementation is education-based.

“There is just not enough time in an endodontic residency to teach surgery,” Dr Torabinejad laments. “If the endodontist isn’t adequately trained in endodontic surgery, they may refer the patient to an oral surgeon who also may not be adequately trained, resulting in the extractions of teeth that could have been saved.”

The shortage of residencies that train students in endodontic surgery also means there is a shortage of teachers, but Drs Torabinejad and Rubinstein hope their textbook will help bridge these gaps. “Our book covers endodontic surgery and the rationale behind it from A to Z,” Dr Torabinejad explains, “and the surgical videos included with the book will allow readers to see how endodontic surgeries are performed so they will be more comfortable performing them.”

In an era where dental implants are widely used and generally successful, it may not seem especially detrimental to extract a compromised tooth and replace it with an implant. However, a recent survey by the American Association of Endodontists found that patients have strong opinions favoring the retention of their natural teeth. According to the survey, most participants were not aware that root canal treatment is a viable alternative to tooth extraction, but 76% of participants would prefer to have a root canal than a tooth extraction. From these results, it can be inferred that patients prefer the most conservative approach—both medically speaking and financially. And that should be enough to inspire clinicians to broaden their repertoire.

“I was presenting at a conference,” Dr Rubinstein recalls, “and we were asked, ‘What do you think makes a specialist a specialist?’ I said, ‘Our willingness to take risks for our patients.’ Afterward, someone came up to me and said he took great offense at my implying he doesn’t take risks for his patients because he doesn’t perform surgery. So I asked him if he thought he would be more open to endodontic surgery if he’d had training for it in his residency, and he said maybe. He came back to me before the end of that conference and said he thought I may be right and asked if I had any recommendations for workshops he could take. There is a personal comfort level that we as clinicians have to push past so we can better serve our patients.”

The Art and Science of Contemporary Surgical Endodontics is an excellent start to meeting that educational need, and the authors hope it will serve as a catalyst for educators and clinicians to rethink the way they define conservative endodontic treatment and as a learning tool for those eager to broaden their horizons.


Mahmoud Torabinejad, DDS, MSD, PhD, is a professor of endodontics and director of the advanced specialty education program in endodontics at Loma Linda University School of Dentistry. He has made over 200 national and international presentations in more than 40 countries, has authored four textbooks and more than 300 publications, and is the top-cited author in endodontic journals with authorship in 16 articles of the top 100 list. He has received numerous awards and accolades, including the Edward D. Coolidge Award from the AAE in 2016 for displaying leadership and dedication to dentistry and endodontics. He is past president of the California Association of Endodontics and past president of the American Association of Endodontists and its Foundation.

 

 

Richard Rubinstein, DDS, MS, received his dental degree in 1971 and his endodontic training in 1973, both from the University of Michigan School of Dentistry, where he is currently an adjunct clinical professor in the Department of Cariology, Restorative Sciences and Endodontics. He is an internationally renowned speaker and pioneer in the use of the operating microscope in endodontics. In addition to writing numerous scientific articles on the surgical operating microscope and endodontic microsurgical technique, he is a contributing author of several endodontics textbooks. He is a Fellow of the American College of Dentists and maintains a private practice limited to endodontics in Farmington Hills, Michigan.

Posted in Books, Endodontics | Tagged , , , , , , , , , | 1 Comment

Quintessence Roundup: April

Quintessence 2017 Catalog

New Titles in Books


The Art and Science of Contemporary Surgical Endodontics
(Book/DVD set)

Edited by Mahmoud Torabinejad and Richard Rubinstein

This book begins with a concise review of the basic science of tissues and then moves into diagnosis, treatment planning, and surgical procedures in endodontics, with an emphasis on the use of enhanced magnification, ultrasonic tips, microinstruments, newer root-end filling materials, and CBCT. Chapters on the maxillary sinus and its relation to surgical endodontics, soft and hard tissue healing, and adjunctive surgical procedures and considerations such as management of procedural accidents, resorption, root amputation, hemisection, replantation, transplantation, crown lengthening, grafting materials, and pharmacology are followed by an assessment of the outcomes of surgical endodontics based on current evidence. The accompanying DVDs present valuable videos demonstrating many of the procedures. These features provide the reader with a textbook that is concise, current, and easy to follow in an interactive manner. Written by a team of leading authorities and richly illustrated, this new compendium of state-of-the-art knowledge and protocols is essential reading for practicing endodontists and residents alike.

336 pp; 685 illus; ISBN 978-0-86715-731-4 (B7314); Special preorder price! US $158

 

Noncarious Cervical Lesions and Cervical Dentin Hypersensitivity: Etiology, Diagnosis, and Treatment

Edited by Paulo V. Soares and John O. Grippo

Cervical dentin hypersensitivity (CDH) and noncarious cervical lesions (NCCLs) are common findings in modern clinical practice. Although research has shown that NCCLs are a multifactorial condition involving the three mechanisms of stress, biocorrosion, and friction, few dentists know how to treat them effectively. Similarly, CDH has been an enigma for many years, and research has focused on etiology instead of treatment. In addition, little attention has been given to their mutual etiologic mechanisms of cervical stress concentration from occlusal loading and endogenous/exogenous biocorrosion. Therefore, this book approaches CDH and NCCLs together and outlines the history, mechanisms, and, most important, the clinical methods of treatment for these pathologies. It is about time we as dentists learn how to treat and prevent these conditions in clinical practice. This involves greater diagnostic effort and alteration of treatment protocols to (1) reduce dietary intake/exposure to acids, (2) manage reflux diseases, and (3) consider the significance of occlusal therapies. After reading this book, the student or clinician will be able to diagnose and treat clinical cases of NCCLs and CDH.

208 pp; 425 illus; ISBN 978-0-86715-714-7 (B7147); Now available! US $155

Read more about NCCLs and the group of researchers behind this book here!

EndoProsthodontics: A Guide for Practicing Dentists

Edited by Maciej Żarow

Written by renowned international experts in the field of restoration of endodontically treated teeth, this book details the endodontic, restorative, and esthetic principles of treating pulpless teeth. Topics include how to avoid fractures, endodontic retreatment versus extraction and implant placement, use of direct and indirect restoration, tooth whitening after endodontic treatment, use of fiber posts, treating subgingival defects, and use of porcelain veneers versus ceramic crowns. Each chapter includes detailed clinical cases, step-by-step descriptions of technical protocols, algorithms, and practical tips for everyday use.

324 pp; 1423 illus; ISBN: 978-83-85700-90-6 (B9451); US $106

 

New Issues in Journals


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Featured article: Subperiosteal Minimally Invasive Aesthetic Ridge Augmentation Technique (SMART): A New Standard for Bone Reconstruction of the Jaws
Ernesto A. Lee

Clinical and Histologic Evaluations of SLA Dental Implants
Myron Nevins, Stefano Parma-Benfenati, Franco Quinti, Prima Galletti, Cosmin Sava, Catalin Sava, and David M. Kim

Dynamic Documentation of the Smile and the 2D/3D Digital Smile Design Process
Christian Coachman, Marcelo Alexandre Calamita, and Newton Sesma

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Digital Design and Fabrication of Surgical Obturators Based Only on Preoperative Computed Tomography Data
Jeff Rodney and Ivan Chicchon

Bruxism: Is There an Indication for Muscle-Stretching Exercises?
Simone Gouw, Anton de Wijer, Nico H.J. Creugers, and Stanimira I. Kalaykova

Feasibility and Accuracy of Digitizing Edentulous Maxillectomy Defects: A Comparative Study
Mahmoud E. Elbashti, Mariko Hattori, Sebastian B.M. Patzelt, Dirk Schulze, Yuka I. Sumita, and Hisashi Taniguchi

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Featured Article: Are “Human Factors” the Primary Cause of Complications in the Field of Implant Dentistry?
Franck Renouard, René Amalberti, and Erell Renouard

Thematic Abstract Review: Immediate Implant Placement and Restoration: An Update
Guy Huynh-Ba

Extraoral Implants for Anchoring Facial Prostheses: Evaluation of Success and Survival Rates in Three Anatomical Regions
Heitor Batista dos Reis, Joaquim Augusto Piras de Oliveira, Vanessa Arias Pecorari, Shiva Raoufi, Márcio Abrahão, and Luciano Lauria Dib

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Interprofessional Education and Collaboration as an Approach to Overcoming Perceived Barriers in Improving Oral Health
Lorinda Coan and Amanda R. Reddington

Quality Resources for Clinical Decision Making: Part 4. Understanding the Flossing Controversy
JoAnn R. Gurenlian and Jane L. Forrest

Critical Thinking in Action: Consideration of Alternative Hypotheses
Donald M. Brunette

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Topical Review: Potential Use of Botulinum Toxin in the Management of Painful Posttraumatic Trigeminal Neuropathy
Nathan Moreau, Wisam Dieb, Vianney Descroix, Peter Svensson, Malin Ernberg, and Yves Boucher

Pain from Dental Implant Placement, Inflammatory Pulpitis Pain, and Neuropathic Pain Present Different Somatosensory Profiles
André Luís Porporatti, Leonardo Rigoldi Bonjardim, Juliana Stuginski-Barbosa, Estevam Augusto Bonfante, Yuri Martins Costa, and Paulo César Rodrigues Conti

Association Between Chronic Tension-Type Headache Coexistent with Chronic Temporomandibular Disorder Pain and Limitations in Physical and Emotional Functioning: A Case-Control Study
Rüdiger Emshoff, Felix Bertram, Dagmar Schnabl, and Iris Emshoff

Dental Meetings Quintessence Will Attend in April


6th Hawaii Mid Pacific Session
hosted by The International Congress of Dental Esthetics & Technology for Dentists & Dental Technicians
April 15–16 in Los Angeles, California

AACD 2017: Booth #607
hosted by the American Academy of Cosmetic Dentistry
April 18–21 in Las Vegas, Nevada

2017 AAO Annual Session: Booth #510
hosted by the American Association of Orthodontics
April 21–25 in San Diego, California

2017 Annual Scientific Session of the Academy of Prosthodontics
hosted by the Academy of Prosthodontics
April 25–29 in Sarasota, Florida

AAE17: Booth #939
hosted by the American Association of Endodontists, April 26–29 in New Orleans, Louisiana

Upcoming Quintessence Symposia


Posted in Books, Endodontics, Esthetic Dentistry, Implant Dentistry, International Journal of Evidence-Based Practice for the Dental Hygienist, Journal of Oral & Facial Pain and Headache (formerly Journal of Orofacial Pain), Journals, Misc, Multidisciplinary, Multimedia, Periodontics, Prosthodontics, Research, Restorative Dentistry, Roundup, The International Journal of Oral & Maxillofacial Implants, The International Journal of Periodontics & Restorative Dentistry, The International Journal of Prosthodontics, What's New | Tagged , , , , , , , , , , , , , , , , , , | Leave a comment

NCCLs: How a Team of Researchers is Redefining How We Treat Them

Whether you’re a general dentist, dental hygienist, or a specialist, chances are you’ve seen one of these lesions. It’s also likely that if you researched causes and treatment options, you found a lot of contradicting literature. One team of researchers has made it their mission to cut through the fray and shed light on the etiology behind these lesions and offer practical, interdisciplinary treatment protocols for dental clinicians.

When Dr Paulo V. Soares encountered his first noncarious cervical lesion (NCCL) as a dental student in 1999, he was intrigued. This curiosity spurred him onto a path of research that has carried him through many unique disciplines, eventually leading him to found the NCCL Research Group at the Federal University of Uberlândia, Brazil.

“At the beginning of my career, I believed brushing and occlusal forces were the main causes of NCCLs,” Dr Soares recalls. “I did my master’s and PhD theses on biomechanical behaviors, and during that research I read many papers with different points of view about NCCLs. In 2008, I concluded my PhD where I observed high rates of failure for Class V restorations, and then I formed the NCCL Research Group.”

Today, the NCCL Research Group comprises 26 direct members and many more international collaborators from fields of study such as biomechanics, biochemistry, cellular biotechnology, psychology, nutrition, and gastric medicine, in addition to dental areas such as occlusion, endodontics, periodontics, prosthodontics, orthodontics, and operative dentistry. The group’s goal is to clarify the causes of NCCLs and cervical dentin hypersensitivity (CDH) and to explore treatment options that combat the causes of the lesions rather than mask the symptoms. Recently, the group’s research was gathered and developed into a book, Noncarious Cervical Lesions and Cervical Dentin Hypersensitivity: Etiology, Diagnosis, and Treatment edited by Drs Soares and John O. Grippo.

The reason the NCCL Research Group is so diverse is that the treatment of NCCLs and the control of CDH require a multidisciplinary view and approach. For decades, dental management and treatment of NCCLs focused on occlusal mechanisms and interventions such as restorative or periodontal procedures and ignored many of the underlying etiologic factors. When these factors are left unexamined and untreated, Class V restorations fail and the cycle repeats itself.

“NCCLs and CDH require a complete analysis of a patient as a member of your respective context/society,” Dr Soares explained. “We need to teach clinicians and future professionals that we can’t analyze just the teeth or mouth.”

Note the severe NCCLs resulting from dentin degradation in this 50-year-old woman with a highly acidic diet. (Courtesy of the NCCL Research Group, Uberlândia, Brazil.)

Aggressive NCCLs on the palatal surface of the maxillary anterior teeth in this 45-year-old man with diagnosed but untreated GERD. The teeth look as though they have been prepared for a full-coverage restoration with a chamfered margin. (Courtesy of the NCCL Research Group, Uberlândia, Brazil.)

When the NCCL Research Group included the expertise of a variety of non-dental professionals and researchers, they were able to combine individual findings and opinions into a much broader overview of etiologic factors than was previously recognized by the dental industry. These factors include parafunctional habits and their connection to psychologic stress, systemic diseases such as gastroesophageal reflux disease (GERD), dietary components, and occupational effects.

The NCCL Research Group’s findings prove that when clinicians have a narrow view of NCCLs and CDH, they set themselves up for a narrow rate of success. The high failure rates of Class V restorations are related to incomplete comprehension of the causes and progression of these conditions. Adhesive restorations treat the lesion or hypersensitivity, but they don’t stop progression or solve the problems. The etiologic factors behind the progression of NCCLs naturally promote early failure and debonding of Class V restorations; however, if clinicians take a more holistic approach to evaluating the patient-specific factors, treatment plans can be redesigned to treat the underlying causes through nonrestorative techniques before tackling the restorative and/or surgical options to restore tooth structure and alleviate symptoms.

What Causes NCCLs and CDH?

NCCLs are related to three distinct and fundamental etiologic mechanisms: stress, friction, and biocorrosion. The micromorphology of the tooth structure, particularly how enamel prisms and dentinal tubules are oriented in the cervical region as opposed to the incisal region, directly influences the area of origin and progression of NCCLs. The enamel is also thinner and more brittle at the cervical region, making it more vulnerable to stress fractures as well as biocorrosion in this area.

(left) Biocorrosive abfraction ridges within the wedge-shaped NCCL resulting from variation in the location of the tensile stress concentration over time combined with a biocorrodent, resulting in a lesion with irregular morphology attributed to a changing fulcrum toward the apex of the tooth. (right) Clinical aspects of biocorrosive abfraction ridges, or “progression lines,” within the wedgeshaped NCCL.

Maxillary right quadrant of a patient with GERD and bruxism. Biocorrosion of the teeth has been accelerated by attrition and abrasion.

Some of the most visually dramatic NCCLs are wedge-shaped abfractive lesions, which occur when the force of stress concentration exceeds the tensile strength of the dental tissue, leading to micro- and macrofractures at the cervical region. The most potentially damaging forces occur during intercuspation of the teeth during lateral excursion or anterior slide from centric relation to maximal intercuspal position, either during normal function or parafunction. The direction of eccentric occlusal loading will affect the stress concentration and strain pattern. With this in mind, in some cases one of the warning signs of future NCCL development can be wear facets on the occlusal surfaces. Patients with parafunctional habits should be considered at risk for NCCLs and CDH and should be evaluated closely for disease progression.

Biocorrosive abfraction is greater on the facial than on the lingual due to the lack of serous saliva on the facial.

Further compounding the progression of NCCLs is the lack of saliva on buccal surfaces. When present in required amounts, saliva can neutralize biocorrosive exposures and, to a certain extent, repair and remineralize damage to the tooth structure. Potential biocorrosive exposures include dietary sources (eg, citrus fruits, soda, white wine) and occupational or recreational exposures, such as chlorine exposure for professional and recreational swimmers. The combination of stress and biocorrosion can cause more damage than either acting alone.

During a biocorrosive challenge, a chemical reaction occurs between an acid and the components of dental structures. Hydrogen ions released by the acids combine with carbonate and phosphate ions within the mineral crystals of the tooth structure, resulting in chemical degradation and etching. Enamel is more vulnerable to acid action than dentin due to its larger crystal size and porosity. Continuous exposure to acids will remove the smear layer, exposing vulnerable dentinal tubules and leading to CDH. Even when the strength of the acid challenge is not great enough to result in direct removal of the enamel layer, it can result in a thin, softened layer that can be further degraded by mechanical wear and abrasion.

List of acidic foods and drinks from most acidic to least acidic.

What Do the NCCL Research Group Findings Mean for Treatment Protocols?

The multidisciplinary composition of the NCCL Research Group enabled them to identify the numerous interrelated causes of NCCLs and CDH that, like the hidden bulk of icebergs, have long confounded clinicians. The incidence rate of NCCLs and CDH increase annually, and with it the rate of published articles that disagree on causes and treatments. By taking an interdisciplinary, holistic view of the problem, the NCCL Research Group has finally found the guide to a 1,000-piece puzzle—but now clinicians have to put it together for their patients.

Note the initial areas of enamel demineralization in the maxillary teeth of this 30-year-old woman with GERD. (Courtesy of the NCCL Research Group, Uberlândia, Brazil.)

“New generations of clinicians will need to change the way they view and treat these diseases,” Dr Soares advises. “Don’t believe that a Class V lesion is one more type of cavity in your patient’s mouth. Know that it is an NCCL and understand that the main factors could be the patient’s lifestyle or habits. Believe that subgingival CDH with or without gingival recession can be the first step of a future NCCL or even an incipient microscopic NCCL. Restoring the missing structure or recommending a desensitizing toothpaste does not complete treatment for your patient.”

Paulo V. Soares, DDS, MS, PhD
Professor and Coordinator of the NCCL Research Group and Public Ambulatory Center
Federal University of Uberlândia
Uberlândia, Brazil

Noncarious Cervical Lesions and Cervical Dentin Hypersensitivity: Etiology, Diagnosis, and Treatment compiles the NCCL Research Group’s research and presents it in a way that is accessible to clinicians and enables them to view these two conditions holistically. Their findings make it imperative that clinicians understand the multifactorial mechanisms at work in order to lower the failure rate for Class V restorations and better manage this growing dental issue.

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