Tạp chí nội nha tháng 11 & 12 /2013 Vol6 No 6

Tạp chí nội nha tháng 11 & 12 /2013 Vol6 No 6

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November/December 2013 - Volume 6 Number 6

ASSOCIATE EDITORS

Julian Webber BDS, MS, DGDP, FICD

Pierre Machtou DDS, FICD

Richard Mounce DDS

Clifford J Ruddle DDS

John West DDS, MSD

EDITORIAL ADVISORS

Paul Abbott BDSc, MDS, FRACDS, FPFA, FADI, FIVCD

Professor Michael A Baumann

Garry Nervo BDSc, LDS, MDSc, FRACDS, FICD, FPFA

Wilhelm Pertot DCSD, DEA, PhD

Julian English BA (Hons), editorial director FMC

Dr Paul Langmaid CBE, BDS, ex chief dental officer to the Government for

Wales

Dr Ellis Paul BDS, LDS, FFGDP (UK), FICD, editor-in-chief Private Dentistry

Dr Chris Potts BDS, DGDP (UK), business advisor and ex-head of Boots

Dental, BUPA Dentalcover, Virgin

Dr Harry Shiers BDS, MSc (implant surgery), MGDS, MFDS, Harley St referral

implant surgeon

PUBLISHER | Lisa Moler

MANAGING EDITOR | Mali Schantz-Feld

ASSISTANT EDITOR | Kay Harwell Fernández

EDITORIAL ASSISTANT | Mandi Gross

DIRECTOR OF SALES | Michelle Manning

NATIONAL SALES/MARKETING MANAGER

Drew Thornley

PRODUCTION MANAGER/CLIENT RELATIONS

Adrienne Good

PRODUCTION ASST./SUBSCRIPTION COORD

photocopies and information retrieval systems While every care has been taken in the preparation

of this magazine, the publisher cannot be held responsible for the accuracy of the information

printed herein, or in any consequence arising from it The views expressed herein are those of the

author(s) and not necessarily the opinion of either Endodontic Practice or the publisher.

This quote from the book of John is inscribed on the lobby wall of the Central Intelligence Agency headquarters in Langley, Virginia, and I think of it often while treating patients

In clinical endodontics, as with all science, few things are as important as truth

Our essential sworn duty is to “do no harm.” We risk no greater harm to our patients than when

we proceed on the basis of assumption, presumption, or habit, without first doing everything we can

to ascertain the truth of our patient’s condition

Fortunately, we have tools today that allow us to see more, appreciate more, and evaluate more

of a patient’s condition than ever before

My first epiphany in this realm was while still practicing general dentistry My insatiable quest for continuing education took me to Santa Barbara, California, under the guidance of Dr Cliff Ruddle It was there that I first looked through a dental operating microscope I was literally AMAZED!

French author Marcel Proust once observed, “The true voyage of discovery consists not in seeking new landscapes, but in having new eyes.” As soon as I integrated a dental microscope into

my general practice and peered through the lenses, I understood the truth of Proust’s wisdom

Thanks to the lighting and magnification of the scope, I was seeing the closest thing possible to the truth of my patient’s condition Now I could see, with vivid clarity, every tooth margin I looked, in

intimate detail, at things that I saw clinically…but had not really seen

Shortly, I came to realize another truth: we cannot treat what we cannot see And the better we can see it, the better we can treat it

Proper use of the microscope impacts everyone involved in patient care: the clinician who immediately gains confidence, the assistant (hopefully utilizing the assistant’s binoculars) who can better anticipate and understand the clinical conditions and needs, the office staff who know that their clinicians are providing the most well-informed care possible, and of course, the patients themselves who benefit from potentially reduced chair time, reduced pain and discomfort, decreased recovery times, and less risk of the need for future treatment

While attending graduate school at Boston University, my mentor, Dr Herb Schilder, sometimes referred to me as “The Virus,” because I was so excited about new dental technologies — and I was all too eager to share that enthusiasm with my classmates, my teachers, and anyone else who would listen But the truth is that my love affair is not really with technology itself, but with what I can do with

it And that still holds true today The things that we are able to do today with technology in dentistry are truly amazing

Without question, I consider the dental operating microscope the single most important piece of technology that I have incorporated into my practice

Like the microscope, which I discovered purely by accident, more recently, Cone Beam Computed Tomography (CBCT) has proven to be a practice game changer for me And like the microscope, it has transformed both the way that I practice and the way that I think about truth

I never anticipated the impact that visualizing dental anatomy in 3D would have on my staff,

my patients, my practice, and me CBCT has literally changed the way that I approach clinical endodontics

This technology is the epitome of John’s verse: it represents three-dimensional truth, and the freedom to treat patients confidently, creatively, and effectively because of the truth it provides

CBCT allows me to visually strategize the clinical execution of a procedure before I actually do

it, whether it’s endodontic therapy, a careful manipulation of the Schniderian membrane for a sinus lift, or the placement of a dental implant — either done “free hand” or utilizing CBCT’s DICOM data to create a computer-generated surgical guide

Beyond visualizing the anatomy prior to the procedure, having the 3D scan on a large resolution monitor chairside provides a true representation of the operating space, and an incredible level of pretreatment confidence along with it

high-Procedures that once were difficult and created significant pretreatment anxiety for doctor, staff, and patient are now commonplace and are executed with ease To the benefit of all, with CBCT we can digitally document the entire scope of a procedure, from initial evaluation, through treatment planning, and eventually, years of follow-up This gives us the great luxury of going back to review past cases and learn from our own experiences, as well as to provide extensive treatment feedback

to our referring doctors and the colleagues with whom we consult

With today’s technologies, endodontic professionals are closer than ever to attaining that ultimate scientific pursuit of truth New tools and ever-evolving technologies add limitless stimulation

to the practice careers of those who embrace them, and ultimately set us free in the greatest way imaginable: by giving us the freedom to continue to grow at what we do best, for our patients, our colleagues, and ourselves

Thomas V McClammy, DMD, MS aka: Clamdawg

North Scottsdale Endodontics & Implantology (Arizona)Foundational Dental Seminars

Few things are as important as truth

“And ye shall know the truth and the truth shall make you free…” ~ JOHN VIII-XXXII

Top ten tips: Tip number 10 - When things go wrong

In the last article in this series, Dr Tony Druttman focuses what to do when things do not go according to plan 18

Drs Derek Chu, David Jaramillo, Chad Gustafson, and Dwight Rice study the

benefits of CBCT, and its role in helping to diagnose and treat endodontic

problems

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TABLE OF CONTENTS

Continuing

education

Fiber posts and tooth

reinforcement: evidence in the

literature

Drs Leendert Boksman, Gary

Glassman, Gildo Santos, and Manfred

Friedman look at the literature for fiber

posts and the best techniques for

placement 22

Management of an upper first

molar with three mesiobuccal root

canals

Dr Peet van der Vyver presents a

case report to illustrate the clinical

management of an upper first

maxillary molar tooth with three

mesiobuccal root canals, using the

ProTaper Next system 28

Abstracts

The latest in endodontic research

Dr Kishor Gulabivala presents the latest literature, keeping you up-to- date with the most relevant research 48

Practice management

Technology leads the charge for improved patient experience, increased cash flow

Jena McCoy-Lovern tackles some challenges to establishing and maintaining a positive relationship with patients 54

ORTHOPHOS XG 3D

ORTHOPHOS XG 3D The right solution for your diagnostic needs.

Implantologists

will appreciate the seamless clinical workflow from initial diagnostics, to treatment planning, to ordering surgical guides and final implant placement.

Endodontists

will enjoy instantly viewable 3D volumetric images for revealing and measuring canal shapes, depths and anatomies.

Orthodontists

will benefit from high- quality pan and ceph images for optimized therapy planning.

General Practitioners

will achieve greater

diagnostic accuracy

for routine cases.

“With my Sirona 3D unit, I can see the anatomy of canals, calcification, extent of resorption, tures, and sizes of periapical radiolucencies, all of which influence treatment plans for my patients Combine that with the metal artifact reduction software that reduces distortions from metal objects,

frac-my treatment process is a lot less stressful My patients benefit from the technology and frac-my

referrals appreciate the value.” ~ Dr Kathryn Stuart, Endodontist - Fishers, Indiana

The advantages of 2D & 3D in one comprehensive unit

ORTHOPHOS XG 3D is a hybrid system that provides clinical workflow advantages, along with the lowest possible effective dose for the patient Its 3D function provides diagnostic accuracy when you need it most: for implants, surgical procedures and volumetric imaging of the jaws, sinuses and other dental anatomy

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What can you tell us about your

background?

I grew up in Northern New Jersey, and would

like to say I spent endless summers hanging

at the shore, but I actually spent summers

working with my father doing construction

since the fourth grade I benefited from a

liberal arts education and graduated from

Lycoming College with honors I attended

the University of Medicine and Dentistry,

receiving both graduate and postgraduate

degrees I also enjoyed being an Associate

Clinical Professor for 10 years I started my

first practice right out of school and have

opened five offices in New Jersey since

then

Is your practice limited to

endodontics?

I am often asked if our practice is just

limited to endodontics My answer is we

are limited to comprehensive endodontics

We limit ourselves to root canals, surgical

endodontics, facial pain diagnosis,

occlusion, TMD, and patients with special

needs A complete postgraduate program

touches upon many areas of endodontics,

and it is up to individuals what they limit

themselves to

What training have you

undertaken?

You are never done training and learning

Take continuing education courses that

are not endodontic in nature Anatomy,

microbiology, restorative, and pathology

helps you communicate with your peers on

a more thorough comprehensive basis

Why did you decide to focus on

endodontics?

So, why endodontics? At first, I thought

it was fun, I had an aptitude for it, and

loved doing it I had a deep respect for the

instructors in my department To this day, I

still love going to work

How long have you been

practicing, and what systems do

you use?

I have been fortunate to be practicing for

close to 25 years There was once a time

when I use to say: “We have to be able to

do this on computers!” Careful for what you wish for Plumber, move over on my speed dial, computer technician, step right in We review radiographs from many different software systems We have been exceptionally pleased with companies such

as Adec, Schick, and Planmeca The detail and support we feel has been consistent and dependable

Who has inspired you?

I was first and still inspired by my family dentist, Dr Anthony Cipriano I could tell as

a teenager he really enjoyed what he did

Patients can sense that, young to old That may be the tip of the day

What is the most satisfying aspect

of your practice?

We are tooth savers! When told the tooth can’t be saved, nothing is more satisfying then keeping that tooth right where it erupted Origin of facial pain, yes, we have

it figured out; let’s put you in the right direction The practice’s scope of treatment expands as well as the opportunity to collaborate with many of our colleagues from medicine to dentistry

Professionally, what are you most proud of?

On a professional level, I am most proud

of my fellow colleagues in the office, both doctors and staff “I’d rather be having a root canal.” Guess what? — you are! We work hard to make our patients want to come back

What has been your biggest challenge?

The biggest challenge we face is to have others understand that many teeth indicated for extraction can be saved Quality CBCT imaging makes diagnosing and treatment more predictable

What would you have become if you had not become a dentist?

I was fortunate to choose my profession

As a child growing up, I wanted to be an astronaut My career would have ended early; I have to take Dramamine before I go

on carnival rides with my daughter

What is the future of endodontics and dentistry?

The future of endodontics is found in

Dr Brian Trava

PRACTICE PROFILE

Multidimensional endodontics

“The ASI Endodontic carts are a great convenience This space

saving design allows me to be organized and efficient with only one

foot control and without all of the cords draped over my counters.”

– Dr Kelly Jones

The Cart, With Only One Foot Control

The versatility of ASI’s custom integrated cart system

allows for infinite positioning of the cart

to easily maneuver within close reach

during procedures and then out of patient

view after procedures Adding a monitor

mount creates an intimate environment for

both patient education and clinical use.

Side Delivery

An ASI cart positioned at the doctor’s

dominant side requires the least amount of

tasking movements during a procedure and

works efficiently with microscope dentistry

Foot Control Placement

The foot control tubing of an ASI system can

be run underneath the floor through a conduit

from the junction box to the patient dental

chair The end result creates easy access to

the foot control without tubing running

across the floor

The Junction Box

In addition to attractively concealing the standard

connections of compressed air, suction and electricity,

ASI’s unique in-wall junction box allows computer

connections such as video, USB, network and other

IT connections throughout the office to be easily

organized and safely hidden from view.

1-800-566-9953 • asimedical.net

Achieve the Optimal Treatment Room with ASI

PRACTICE PROFILE

research and technology Endodontic

research has given us a much more

comprehensive understanding of microbial

infections, biofilm, and anatomy Our

practice has been the first to incorporate

both CBCT and lasers in many ways to treat

our patients Patients are more educated,

they want to save their natural teeth, and

we have the tools available to us

What are your top tips for

main-taining a successful practice?

1 Listen to the patient

2 Be fair to the patient

3 Make sure the patient understands

what you’re doing and why you’re

The best advice that I can give to a budding

endodontist is twofold Look beyond the tooth Take what you learned in school, and use it to treat the whole patient To make it easier, invest in quality equipment backed by quality companies Do your research Look for a quality CBCT machine,

a machine that allows you to study and diagnose the oral maxillary complex, TMJ, and sinus with great detail

What are your hobbies, and what

do you do in your spare time?

Endodontics can be demanding It is best

to have distractions to take your mind away from the office So, I became a soccer mom with my wife There is nothing like kids to help you forget about the office for

a weekend Typically, when I am asked to lecture across the country, the first place

I look for is a National Park to incorporate into our trip It’s a great way to really appreciate what we work for

TOP 10 FAVORITES LIST

1 My number one most indispensible piece of equipment in my office, our Promax 3D.

2 Explaining to patients how their CBCT image has given me the detail I need to help them

3 Being the first to use the Waterlase MD to treat lesions without making a surgical flap.

4 Working with the NBA in Africa to help children

5 Treating kids and special needs individuals when they were turned away from other practices.

6 Telling patients at 3 a.m that it is normal; everybody calls me at this time to tell me they had a toothache for 2 weeks

7 Having the opportunity to learn from other colleagues while lecturing in different areas

This EHR Module is 2011 compliant and has been certified by an ONCDATCB in accordance with the applicable certification criteria adopted by the Secretary of Health and

Human Services This certification does not represent an endorsement by the U.S Department of Health and Human Services or guarantee the receipt of incentive payments.

You might have the slickest looking offi ce in town, but is your software still from the Stone Ages? At TDO,

we believe you deserve a software system that helps your practice grow, not one that gets in your way.

TDO Software allows you to provide the best possible patient care Only TDO enables your staff to be their

best by eliminating time-wasting ineffi ciencies in the offi ce TDO makes it easy to keep current with the

latest technology, terminology, materials and techniques With TDO

you can create professional-looking referral and CBCT reports and

print, email or publish them on your website with just one click.

Take your practice out of the museum and into the

world of modern endodontics Evolve today with

TDO Software.

ARE YOU A DINODONTIST?

TDO_GSR_062113_endo_practice_mag.indd 1 6/22/13 12:11 AM

Company history

Planmeca is the world’s largest privately

held dental imaging company and one of

the industry’s leading manufacturers of

panoramic and cephalometric X-rays Over

the past four decades, it has expanded its

sales network in more than 100 countries

worldwide Planmeca’s imaging units

offer superior image quality, reduced

radiation during routine procedures, easy

upgradeabililty, and advanced,

user-friendly imaging software Planmeca

has been a leader in digital imaging and

advanced computer-integrated dental

care concepts for years and remains in

the forefront of technology as the field of

dentistry evolves

Since the company’s establishment,

Planmeca’s developers have worked

closely with dentists and leading universities

to anticipate future trends, using this data

to design an advanced line of high-tech

products From the introduction of the

first microprocessor-controlled chair, to

the development of the ProMax™ line of

imaging units with SCARA (Selectively

Compliant Articulated Robotic Arm)

technology, Planmeca has always led the

way with new technology The company’s

goal is to supply dental professionals with

the highest quality dental equipment that

is uniquely designed for today’s modern,

technologically advanced practice

Patented SCARA technology

What truly sets Planmeca apart from the

competition is the company’s patented,

exclusive SCARA technology This robotic

arm, which comes standard on all ProMax

units, enables free geometry based on

image formation and can produce any

movement pattern required The precise,

free-flowing arm movements allow for

a wide variety of imaging programs not

possible with any other X-ray unit on the

market; this allows the dental professional

to take images based on diagnostic needs,

not machine limitations

Anatomically accurate extraoral

bitewing program

Planmeca’s ProMax S3, 3D, and 3D

Mid imaging units offer an exclusive

extraoral bitewing program, possible

only with SCARA technology This

innovative program consistently opens

interproximal contacts, eliminates patient positioning errors, and is more diagnostic than other intraoral modalities ProMax extraoral bitewings are ideal for a number

of patients, from the elderly and those requiring periodontal work to those with claustrophobia, sensitive gag reflexes, or those in pain All of this comes in a true bitewing program that enhances clinical efficiency and takes less time and effort than a conventional intraoral bitewing

Upgradeable innovation

One of Planmeca’s greatest contributions

to dental imaging is its innovative, upgradeable product platform — all based

on exclusive, patented SCARA technology

Since it’s software-driven, SCARA technology enables limitless possibilities

to upgrade existing equipment, allowing the new dentist on a smaller budget to grow while making only appropriate and necessary equipment investments For example, Planmeca products can be upgraded from a 2D panoramic X-ray to a combination of pan/ceph capabilities, which can be further upgraded to accommodate 3D imaging needs Whether it is the transformation of a film to a 3D unit, or the addition of a cephalometric arm, Planmeca offers solutions for every upgrade need

This single piece of technology makes the ProMax the most versatile all-in-one X-ray unit available on the market

Reduced radiation for safer procedures

All Planmeca products are designed around the ALARA radiation principle (As Low As Reasonably Achievable) Through specially designed programs, such as horizontal and vertical segmenting, autofocus, and pediatric pans, dental professionals are able to provide their patients with excellent care without compromising their safety

Horizontal and vertical segmenting options limit the exposure to diagnostic areas of interest By selecting these options, patient dosage can be reduced by

up to 93%, which is highly advantageous when follow-up images are needed

Autofocus automatically positions the focal layer using a low-dose scout image

of the patient’s central incisors, and uses landmarks within the patient’s anatomy

to calculate placement The result is a

fast, diagnostic pan every time, which drastically reduces retakes caused by false positioning

Pediatric programs further lower the dose by automatically selecting the narrow focal layer of young patients, adjusting the collimator, and reducing the area of exposure from the top and the sides This reduces the dosage area while still providing full diagnostic information

Digital Perfection™: the new standard

Building on the well-established all-in-one idea of integration, Planmeca introduced the Digital Perfection concept in 2011 Seamless integration of dental equipment and software creates efficient diagnostic tools, optimized workflow, and advanced infection control methods that result in a treatment environment where all equipment shares an open interface

The company works worldwide with all aspects of the dental industry, including dental schools, dentists, and dental team members, as well as dealers, and uses the latest technologies to create the best products for dental offices and patients alike As a forerunner in digital imaging technology, Planmeca delivers complete dental solutions based on integrated high-tech device and software options with exquisite design

For more information, visit www.planmecausa.com

This information was provided by Planmeca.

Planmeca ® : innovative, upgradeable imaging technology

CORPORATE PROFILE

“The company’s goal is to supply dental professionals with the highest quality dental equipment that is uniquely designed for today’s modern, technologically advanced practice.”

EP

Introducing the all new

© 2013 Obtura Spartan Endodontics The 3 free tips included with a purchase of the Spartan Wave are the BUC 1, BUC 3, and CPR 4 and will be shipped with the unit See instructions for use Rx Only Products may not be available in all areas Please contact your Obtura Spartan Endodontics Sales Representative for availability and pricing Obtura Spartan Endodontics – 2260 Wendt Street, Algonquin, IL 60102

with purchase of The Spartan Wave*

Ultrasonic Tips

™

“ This is the unit I presently use,

its accuracy is superb and

it works f lawlessly

-Dr Paul F Bery Evanston, IL

”

Endodontic therapy is performed millions

of times a year with relatively high

success rates Success is based on an

accurate diagnosis and execution of the

indicated treatment plan Advancements

in the treatment and diagnosis of root

canal therapy (apex locators, development

of NiTi instruments, rotary instrumentation,

new irrigating solutions, evolving technique,

and cone beam computed tomography

(CBCT) all play important roles in treatment

success The application of new technology

has made major advances in diagnosis

and treatment, particularly in the area of

radiography

Radiographic assessment and clinical

tests are essential in making an accurate

diagnosis Radiographic interpretation

allows evaluation for the presence of

periapical pathosis, hard and soft tissue

configurations, and other contributing

factors in patient care High quality

radiographic evaluation is an essential

component in objectively diagnosing teeth

with suspected endodontic problems

(Patel, et al., Ozen, 2009, and Yoshioka,

2011)

It is well established that conventional

periapical radiographs have limitations such

as anatomical noise, two-dimensional and

geometric distortions (Humonen & Orstavik,

2002, Patel, 2009) Conventional intraoral

radiographs image a three-dimensional

structure and display it onto a

two-dimensional surface, causing the image

to have overlaps, distortion, and blockage

of key anatomical structures This results

Endodontics in 3D

CASE STUDY

Drs Derek Chu, David Jaramillo, Chad Gustafson, and Dwight Rice study the benefits of CBCT, and its role

in helping to diagnose and treat endodontic problems

in more radiopaque structures masking or blocking more radiolucent structures With the development of CBCT, it is now possible

to overcome some of these limitations

CBCT technology is significantly more sensitive than conventional radiography in detection of apical periodontitis (Estrela, 2008) CBCT scans are now able to aid in difficult endodontic diagnostic cases where clinical tests and conventional radiology are

inconclusive

Detection of apical periodontitis can be accomplished earlier with CBCT than with conventional radiography because CBCT detects bone loss prior to the involvement

of cortical bone Earlier detection and diagnosis of bony involvement associated with apical periodontitis may allow earlier intervention, if appropriate, which can result in superior treatment outcomes

Referral PA

Derek Chu, DDS, is Assistant Professor, Department

of Endodontics, Loma Linda University School of

Dentistry, California.

David E Jaramillo, DDS, is Associate Professor,

Department of Endodontics, Loma Linda University

School of Dentistry.

Chad Gustafson, DDS, is in Private practice in

Endodontics in Central California.

Dwight Rice, DDS, is Associate Professor, Department

of Oral Diagnosis Radiology and Pathology, Loma Linda

University School of Dentistry.

Endodontist’s PAs

Postoperative radiographsPossible involvement of tooth No 12 but could also be thin buccal plate

CASE STUDY

CBCT technology has been shown to

detect 28% more periapical pathosis

versus conventional radiography (Patel, et

al.)

The following three case reports will

demonstrate the benefits of CBCT, and

its role in helping to diagnose and treat

endodontic problems

Case report No 1

The patient presented to the Loma Linda

University School of Dentistry graduate

endodontic clinic for endodontic evaluation

of tooth Nos 11 and 12 The patient had

mild tenderness when pressing below his

eye on the left side for several months He

had no pain on chewing, and it had never

awakened him The oral exam revealed

CASE STUDY

6/18/2012

extensive crown and bridge reconstructive

dentistry Tooth Nos 11-13 were restored

with porcelain-fused-to-metal crowns with

tooth No 11 serving as an abutment for

a multiunit bridge There was no sinus

tract, and probing depths were 2-3 mm

around tooth Nos 11-13 There was no

tenderness to percussion

Preoperative radiographs

Palpation over the buccal apical area of tooth Nos 11 and 12 was consistent with the patient’s chief complaint and a hard, bony-like swelling was noted in the vestibule, which was not present on the contralateral area of tooth Nos 5 and 6

Tooth Nos 11-13 responded to cold, but the response was delayed Two PA

radiographs were taken, but no definitive periapical pathosis was noted, and the PDL appeared normal around all apices

No endodontic cause could be found

A small field of view CBCT scan was recommended to identify location and size

of expansive lesion

The CBCT indicated a periapical radiolucency surrounding the apex of

CASE STUDY

Pano Scout

tooth No 11 The apical bone surrounding

tooth No 12 appears to be normal The

radiolucency is consistent with a periapical

granuloma or cyst related to a necrotic

pulp tooth No 11 A tentative diagnosis

No 11 necrotic pulp/symptomatic apical

periodontitis was determined Root canal

treatment was recommended for tooth No

11 The canal was cleaned and shaped to

length The canal was obturated with warm

vertical compaction and GP The access

was sealed with a bonded composite

restoration A 6-month follow-up visit was

recommended to evaluate apical healing

Case significance

Clinical signs and symptoms did not

provide enough information for a conclusive

endodontic diagnosis for tooth No 11,

and no definitive lesion could be detected

with two-dimensional radiographs CBCT

allowed for the detection of apical pathosis

and aided in the diagnosis

Case report No 2

A male patient presented in the Loma Linda

School of Dentistry graduate endodontic

clinic referred for endodontic evaluation

of tooth No 3 He reported having pain

on the upper right side of his mouth He

had mild tenderness when palpating

around the buccal mucosa of tooth No

3 Clinical evaluation showed a sinus tract

present along with purulent discharged

after palpating the swelling The clinical

exam revealed mobility, the periodontal

probings were within normal limits, and

there was no pain to percussion The

radiographs revealed that tooth No 3 had

been previously treated, and the sinus tract

was traced with GP leading to tooth No 3

He recalled that the tooth was previously

treated 2 to 3 years prior Tooth No 3 was diagnosed having a recurring/persistent infection and treatment planned for non-surgical retreatment

During retreatment, a missed MB2 canal was located, cleaned, and shaped

to length Calcium hydroxide was placed in the canals, and the patient was scheduled

to return in 1 week to complete treatment

Final obturation was performed using warm vertical compaction of GP

At a 5-month follow-up, patient reports having tenderness recur when palpating over the area where the previous swelling was Clinical exam reveals slight tenderness to palpation on buccal mucosa

of tooth No 3 again Tooth mobility, percussion, and periodontal probing were

Patel S New dimensions in endodontic imaging:

Part 2 Cone beam computed tomography Int Endod J 2009;42(6):463–475.

Patel S, Horner K The use of cone beam

computed tomography in endodontics Int Endod

J 2009;42(9):755–756.

Patel S, Dawood A, Whaites E, Pitt Ford T New dimensions in endodontic imaging: part

1 Conventional and alternative radiographic

systems Int Endod J 2009;42(6):447–462.

Patel S, Dawood A, Mannocci F, Wilson R, Pitt Ford T Detection of periapical bone defects

in human jaws using cone beam computed

tomography and intraoral radiography Int Endod

J 2009;42(6):507-515.

Yoshioka T, Kikuchi I, Adorno CG, Suda H Periapical bone defects of root filled teeth with persistent lesions evaluated by cone-

beam computed tomography Int Endod J

2011;44(3):245–252.

Ozen T, Kamburoğlu K, Cebeci AR, Yüksel SP, Paksoy CS Interpretation of chemically created periapical lesions using 2 different dental cone-beam computerized tomography units,

an intraoral digital sensor, and conventional

film Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;107(3):426–432.

Huumonen S, Ørstavik D Radiological aspects of

apical periodontitis Endod Topics 2002;1(1):3–

25.

CASE STUDY

within normal limits Patient was referred

for CBCT scan for further evaluation

Evaluation of CBCT scan confirmed the

presence of an apical lesion of endodontic

origin, and the patient was scheduled for

endodontic surgery CBCT provided the

opportunity to determine the size of the

lesion and establish the location of the

sinus in preparation for the osteotomy to

be performed The surgery was completed,

and a biopsy sample taken Biopsy report:

periapical granuloma

At 2-month recall, the patient reported

that the pain had subsided The clinical

exam revealed no signs of swelling or sinus

tract All the tests were within normal limits

Case report No 3

A male patient presented in the Loma Linda

School of Dentistry dental hygiene clinic

for routine dental maintenance A firm,

localized, solitary 5 mm swelling on the

inside of the left upper lip (buccal to tooth

No 9) was noted There was also a sinus

tract present associated with the swelling

He reported no pain, and was not aware of

the findings The PA radiographs revealed

an impacted canine superimposed over the apex of tooth No 9

The buccal mucosa above tooth No

9 was red with a slight swelling where the apex of tooth No 9 would be The patient had a CBCT scan to establish the orientation and proximity of tooth No 11

in regards to the apex of tooth No 9 The CBCT scan also showed the presence

of apical periodontitis on tooth No 9, establishing tooth No 9 as the source

of infection Endodontic evaluation and treatment was done prior to evaluation for surgical removal of tooth No 11

CBCT technology demonstrated its important value in these presented cases

CBCT scans provide additional information for visualizing the anatomic features present and for overcoming the limitations

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The causes of endodontic failure are

predominantly of bacterial origin

resulting either from retained microbes or

from those reintroduced into the root canal

space:

1 Untreated and or contaminated canal

space This will include inadequately

cleaned, missed, or ledged canals

2 Instrument separation preventing proper

shaping, cleaning, and obturation of

canal space

3 Perforation

4 Leakage resulting from an inadequate

coronal seal

The successful management of an

endodontic failure depends on many

different factors The correct diagnosis is

of major importance and reference to the

earlier article in this series may be helpful

As CBCT technology becomes more

established, we come to depend more

heavily on it to help diagnose endodontic

failure Even the best quality digital

periapical images will sometimes hide the

truth (Figures 1A and 1B)

When things do not go according to

plan, the best thing to do is to stop and

re-evaluate before making things worse With

experience, correct case assessment can

often prevent pitfalls during treatment

Failure of endodontic treatment

No treatment can be guaranteed to be

100% successful, and endodontics is no

exception, even though success rates of

over 90% can be achieved If an endodontic

failure is diagnosed, it is important to know

why it has failed A very good knowledge of

root canal anatomy is important as well as

an understanding of the techniques used

in endodontic procedures This is why very

often endodontic retreatments are carried

out by specialists and form a significant

proportion of their work

Tip number 10 — When things go wrong

endodontist working in central London He

is also a part-time teacher at the Eastman

Dental Institute, University of London, and

lectures in the UK and abroad.

Figure 1B: The equivalent CBCT image shows an endodontic lesion associated with the MB root

Figure 2A: Endodontic lesion of the mesiobuccal root of tooth No 14

Figure 2B: Retreatment of tooth No 14 including the MB2 canal

ENDODONTICS IN FOCUS

Case assessment should include the

following:

Degree of treatment complexity

Restorability of the tooth

Most endodontic failures are due to the

presence of residual infection This is

caused by canals that have been missed

or canals that have been inadequately

cleaned The most common cause of

failure of upper molars is due to untreated

MB2 canals (Figures 2A and 2B) These

are often missed because they are very

small and difficult to identify without magnification Canal anatomy can be diverse, and it is important to identify all the canals that are present, rather than just the ones that one expects to find It

is also important to appreciate that canals sclerose from coronal to apical, and that the entrance to a canal can be some way apical to the pulp chamber The operating microscope is invaluable in this respect

Inadequately cleaned canals

Conventional understanding is that files shape, and irrigants clean If a canal is oval in cross section, then very often canal debris is packed into the lateral extensions

of the canal, and it is difficult for the irrigants

to remove the debris This is particularly the case in the isthmus region of molar teeth

Often a symptomatic root-filled tooth will look fine on a radiograph, and a diagnosis may be difficult to establish It is important to remember that a radiograph is only a two-dimensional image of a three-dimensional object Tissue remnants may

be left in the root canal after obturation (Figures 3A and 3B) An oval cross section and a circular cross section can look exactly the same on a radiograph

Fractured instruments

Instrument fracture occurs either through torsional stress or flexural failure Fracture due to torsion occurs when the tip or any other part of the instrument binds

in the canal while the handpiece keeps turning When the elastic limit of the metal

is exceeded, fracture of the instrument

Figure 3A: Tooth No 30 appears to be well root treated, and yet has symptoms Figure 3B: Tooth No 30 has been retreated A second distal canal has been identified

Figure 4: Sectioned root tip of root filled showing a round preparation in an oval canal Figure 5: Rotary nickel-titanium instrument fracture due to

coronal binding

ENDODONTICS IN FOCUS

becomes inevitable (Figure 5) This is often

due to the application of excessive apical

force on the handpiece and can occur

coronally as well as apically

Flexural failure occurs because of

metal fatigue The instrument does not

bind in the canal, but rotates freely until the

fracture occurs at the point of maximum

flexure This type of failure is due to their

use in curved canals (Figure 6) Incorrect

rotational speeds and torque settings may

also contribute to this type of failure

The presence of a fractured instrument

does not necessarily cause a failure

The question has to be asked, “At what

point in the procedure did the instrument

separate?” If the mishap has occurred early

in the cleaning and shaping process, and the instrument has blocked the access to the more apical part of the canal, then failure

is likely to occur This is because bacteria left behind are inaccessible to disinfection procedures (Figures 7A and 7B) On the other hand, if the last instrument in the sequence has separated at the working length, then the likelihood is that the canal has already been debrided adequately, and the presence of the fragment may not affect the prognosis of the tooth (Figure 8)

Either way, it is important that the patient

is informed Fracturing an instrument in a canal is not negligent, but failing to inform

the patient is Removal of the instrument is often possible with the aid of the operating microscope and ultrasonics; however, a great deal of care has to be taken not to remove excessive amounts of the tooth structure (Figure 7B)

Perforations

Perforations (Figure 9) can occur when looking for sclerosed canals, and sometimes it is hard to know if the true canal has been located, or if a perforation has been created, even when using magnification Apex locators are very useful in helping to distinguish between the two, and this is recommended as soon as

Figure 8: Fractured instrument in the mesial root 8 years after treatment Figure 9: Perforation of the mesiobuccal root during root canal preparation

Figure 10A: Failed endodontic treatment of tooth No.19 Figure 10B: Endodontic retreatment Note the sealer in the

mesial root beyond the blockage Figure 10C: Six-month review of tooth 19 shows healing of the endodontic lesion associated with the blocked

canals

Figure 6: Instrument fracture due to flexural fatigue in the

mesiobuccal canal of tooth No 15 Figure 7A: Fractured instrument in the distal root of a symptomatic tooth 30 Figure 7B: Tooth 30 fractured instrument removed and the tooth retreated

Perforation

ENDODONTICS IN FOCUS

the canal wall has been breached Strip

perforations occur when canals have been

over enlarged, often by using Gates Glidden

drills too far apically or when the access

cavity has not been shaped correctly

Perforations should be repaired as

soon as possible, preferably at the same

appointment If they are left, bone loss

around the perforation can occur, and

it may not heal if left too long MTA has

proved to be an excellent repair material,

although because it is a material based

on Portland cement, it can be difficult to

control The new bioceramic materials that

are coming onto the market show promise

as MTA substitutes

Blocked canals

There are situations where teeth with

endodontic lesions have canals that remain

blocked in spite of our best efforts These teeth should not be condemned, as very often the lesions will heal This may be due

to the lesion being associated with other canals in the tooth or because the majority

of the bacteria have been removed, and any remaining are entombed and denied access to nutrients (Figure 8) Canals that are apparently blocked to even the smallest of endodontic instruments are often patent, and this is only determined

on the postoperative radiograph, when cement is forced into the uninstrumented part of the canal during obturation (Figures 9A and 9B)

Conclusions

With technologies, such as the operating microscope, ultrasonics, CBCT, high quality digital radiography, and materials

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such as MTA, and more recent substitutes available to us in endodontics nowadays, many teeth can be salvaged, which would previously have been condemned to extraction These include the teeth where previous endodontic treatment has failed, and where there have been procedural errors during treatment

There is an increasing preoccupation within the profession with dental implants driven by the efforts of the industry When

a tooth has to be extracted or has been lost, there is no better substitute than an implant; however, there is nothing better than the natural dentition Endodontics plays a vital role in maintaining the natural tooth, keeping or restoring it to health and function It is important that the skills and knowledge required to do so are not lost

EP

Traditional thinking that a post is only

placed to retain a core and serves

no other purpose may no longer be valid

(Hajizadeh, et al., 2009)

The preservation of dentin during access

opening, shaping the canal, preparing the

root for placement of a post, and during

restoration with an onlay, or full coverage

preparation is critical to the clinical longevity

and success of the final restoration (Pilo,

Shapenco, Lewinstein, 2008) It is now well

recognized that excess removal of dentinal

support, not only in the root but also

coronally, changes the flexural behavior and

resistance to failure, and that overflaring the

canal for straightline access to the canals

weakens the dentinal complex (Trope,

Ray, 1992; Reeh, Messer, 1989; Linn,

Messer, 1994; Panitvisai, Messer, 1995)

Dentin coronally must be maintained, not

only to give support to the core build-up

(Fokkinga, et al., 2005; Creugers, et al.,

2005), but as well, because clinical and in

vitro studies support the fact that survival of endodontically treated teeth restored with posts is directly proportional to the residual coronal dentin that remains (Ferrari, et al., 2007; Oliveira, Denehy, Boyer, 1987) Post preparation of the root canal space must not remove additional dentin, as this contributes to a reduced fracture toughness (Figure 1) Ree, et al., (2010) state that,

“No additional dentin should be removed beyond what is necessary to complete the endodontic treatment.” If this concept is to

be adhered to clinically, then, of course, the use of parallel-sided posts must be eliminated from our clinical protocol, as these posts usually require removal of sound apical radicular dentin, creating sharper internal line angles, resulting in a weakened root and a higher root fracture risk (Figure 2) [Sorensen, Mito, 1998] As well, the parallel post does not complement the tapered shape of the prepared canal, resulting in excess luting composite in the coronal aspect of the canal, which can decrease bonding efficacy and decrease dislocation resistance (Figure 3) [Boksman, 2011]

If we adhere to the concept of minimal dentin removal in the root, and if we recognize that most root canals are ovoid

in shape, then a wholly different treatment approach than what we have been taught

in the past is indicated Boksman, et al., (2013) have recommended utilizing a tapered master quartz fiber post (Macro-Lock Post™ X-RO™ Illusion™, Clinician’s Choice Dental Products) with additional FiberCones™ placed into the irregularity (lateral spaces) of the canal (Figures 4 and 5) This technique is similar to using a master

Fiber posts and tooth reinforcement: evidence in the literature

cementation

Leendert (Len) Boksman, DDS, BSc, FADI, FICD, graduated from the Faculty of Dentistry, University of Western

Ontario, Canada, with a DDS in 1972 After 7 years in private practice, he joined the Faculty of Dentistry

at Western as an assistant professor of operative dentistry, shortly thereafter attaining the tenured position

of associate professor He has authored more than 100 articles and several chapters in textbooks and was

awarded the Ontario Dental Association Award of Merit in 2005 He has recently been appointed as adjunct

professor in the University of Technology Dental School, Jamaica, where he donates his time Dr Boksman is a

paid part-time consultant to Clinical Research Dental and Clinician’s Choice.

Gary Glassman, DDS, FRCD(C), graduated from the University of Toronto, Faculty of Dentistry in 1984 The

author of numerous publications, Dr Glassman lectures globally on endodontics, is on staff at the University of

Toronto, Faculty of Dentistry in the graduate department of endodontics, and is adjunct professor of dentistry

and director of endodontic programming for the University of Technology, Jamaica Dr Glassman is a fellow of

the Royal College of Dentists of Canada, and the endodontic editor for Oral Health dental journal He maintains

a private practice, Endodontic Specialists, in Toronto, Canada

Gildo Coelho Santos Jr., DDS, MSc, PhD, received his DDS (1986) and MSc in dental clinics (1999) from Federal

University of Bahia, and PhD in prosthodontics (2003) from University of São Paulo (Brazil) Dr Santos was

appointed as assistant professor, division of restorative dentistry at the University of Western Ontario Schulich

School of Medicine and Dentistry in 2006, and in 2011 was appointed chair of the division of restorative

dentistry Dr Santos is a part-time consultant (research and development) for Clinical Research Dental and

Clinician’s Choice.

Manfred Friedman, BDS, BChD, graduated from the University of Witwatersrand and Johannesburg (South

Africa) in 1971 and then obtained his BChD Honours at the University of Pretoria in 1980 He immigrated

to Canada in 1987 where he took up a full-time position at the University of Western Ontario (UWO) and

was appointed as director of dentistry at the Southwestern Regional Center for developmentally challenged

adults from 1987 to 1994 He currently has a full-time practice in London, Ontario, restricting his practice to

endodontics, and is a major part-time adjunct professor at Schulich School of Medicine and Dentistry at UWO

Dr Friedman has given numerous courses on endodontics, with particular interests in rotary instrumentation,

endodontic materials, apex locators, and restoring the endodontically treated tooth.

Educational aims and objectives

This clinical article aims to explain why the literature should be scoured to find the best fiber post available and the best techniques for placement.

Expected outcomes

Correctly answering the questions on page 32, worth 2 hours of CE, will demonstrate the reader can realize that materials and techniques for fiber post restoration of endodontically treated teeth are continuously evolving with the inevitable outcome of better clinical results for patients.

CONTINUING EDUCATION

percha point with accessory

gutta-percha points, which is well understood

Utilizing this approach provides several

clinical advantages (Akkayan, et al., 2010;

Maceri, Martignoni, Vairo, 2008; Li et al.,

2011; Mossavi, Maleknejad, Kimyai, 2008;

Porciani, et al., 2008) including:

• More anti-rotational resistance

• Decreased volume of composite or

cement lateral to the post to decrease the

“C” and “S” factor constraints (volumetric

shrinkage)

• Better adhesion to the root canal walls,

resulting in decreased microleakage and

increasing resistance to dislodgement,

as well as decreased likelihood for lateral

perforation

Choosing the right fiber post

The combination of a post (or multiple posts)

that transmits light efficiently, with sufficient extended light-curing time/output, results

in better composite polymerization

The indirect cast gold/metal/zirconia post and core has been largely replaced with a single appointment restoration of a direct post and core Fiber posts such as the UniCore® Post (Ultradent), the quartz fiber posts manufactured by RTD (St Egreve, France), the Macro-Lock X-RO, and the DT Light-Post® (Bisco Canada, BC) have many physical characteristics that make them more desirable clinically, rather than metal and zirconia posts:

1 The elastic modulus (or a material’s stiffness) of fiber posts more closely approximates that of dentin (18.6GPa), allowing some slight flex in function, dissipating stress, and reducing the likelihood of damage to the root (Ferrari,

Scotti, 2002; Duret, Duret, Reynaud, 1996) Stainless steel has an elastic modulus of about 200GPa, titanium alloy 110GPa and zirconia 300GPa (Goracci, Ferrari, 2011) The stiffness of metal and zirconia posts creates more internal stress, zones of tension and shear during function and parafunction (Rodrigues-Cervantes, et al., 2007), which can result in unrestorable catastrophic root fractures

2 Fiber posts have a high flexural strength, and according to a study by Stewardson,

et al., (2004): “The flexural strength of fiber-reinforced composite endodontic post materials exceeds the yield strength

of gold and stainless steel, and two of the FRC (fiber reinforced composite) posts were comparable to the yield strength of titanium.”

It must be noted here that not all fiber posts are created equal There are differences in fracture load, flexural strength, fiber diameter, fiber/matrix ratio, type of fiber (with quartz fiber posts having higher failure resistance), light transmission, shape, post surface adhesion, quality

of fiber, structural defects/voids, and manufacturing quality, which all affect the clinical outcome and longevity (Seefeld, et al., 2007; Freedman, Jain, 2008; Bassi, 2001; Boudrias, Sakkal, Petrova, 2001; Maceri, Martignoni, Vairo, 2008)

The clinician must make an informed choice for choosing a fiber post – looking for the best attributes – in order to select the post with superior properties based

on independent research The dental practitioner must also be aware of the best adhesive combinations and techniques, as there are some incompatibilities between dual-cure core materials and simplified acidic adhesives due to residual acidity

There is a variation in the results of the scientific literature when evaluating fiber posts, not only because of the differences in the posts themselves, but also because of the cementing/

Figure 2: To seat the inserted parallel-sided post into the

tapered canal would require more apical removal of vital

dentinal structure needlessly weakening the root and

creating an apical stress point

Figure 3: The taper of the Macro-Lock post allows respect for the dentin, and ensures a more even and minimal amount of surrounding composite resin, thereby reducing polymerization contraction forces

Figure 4: In irregular or ovoid canals, the use of FiberCones lateral to the Macro-Lock X-RO has many clinical advantages, increasing longevity

Figure 5: A clinical photograph showing the placement of FiberCones laterally to the main Macro-Lock Post, which

decreases composite volume, adds anti-rotational elements, and decreases microleakage

CONTINUING EDUCATION

bonding/adhesive systems used To date,

multiple articles in the scientific literature

support the statement that, “Only specific

combinations of dentin adhesives and

luting cements prove efficient, with total

etch adhesives combined with dual-cure

cement (composite) appearing to be

the best choice” (Dietschi, et al., 2008;

Radovic, et al., 2008)

3 Fiber posts are not subject to galvanic

or corrosion activity The corrosion of base

metals predisposes to a high percentage

of failures with cast posts, which can also

create a negative esthetic outcome of a

dark root and darkening of the gingival

collar (Figure 6A) [Rosenstiel, Land,

Fujimoto, 2000; Torbjorner, Karlsson,

Odman, 1995] Milnar (2010) and others

have published excellent papers showing

that the use of a light-transmitting post can

eliminate this common esthetic challenge,

allowing not only light transmission down

the canal, eliminating the dark gingival

color, but also the creation of superb

clinical esthetics with translucent ceramics

over a composite core (Figure 6B) [Martelli,

2000; Strassler, 1999]

4 Clinically, heavily restored teeth may hold

up to normal occlusal function but many fail

in cyclic fatigue-repeated functional, stress

and torque (Duret, Duret, Reynaud, 1996)

Fiber posts are more fatigue resistant than

metal posts, and the quartz fiber post is

found to be more than twice as fatigue

resistant as the stainless and titanium

alloy posts (Wiskott, et al., 2007) During

repeated fatigue loading, the flexural

strength of metal posts can decrease by

40%, while there is only a 14% decrease

in a fiber composite post (Duret, Duret,

Reynaud, 1996)

5 Endodontic procedures fail due to

faulty technique, the inability to access or

completely debride a canal, microleakage/

bacterial contamination/exposure to

endotoxins after endodontic therapy is

performed, but before a final restoration is

placed (all endodontic procedures should

be followed by immediate restoration)

[Magura, et al., 1991; Alves, Walton, Drake,

1998], or due to failure and microleakage

of the coronal restoration It has been

estimated that 25% of retreatments involve

the presence of a post Fiber posts are

atraumatically removed in a matter of a few

minutes with available proprietary removal

drill systems (Anderson, et al., 2007;

Frazer, et al., 2008; Gesi, et al., 2003)

No discussion of the restoration of a

badly broken-down endodontically treated

tooth would be complete without discussing the concept of the circumferential ferrule, which is defined as “a metal band or ring that encircles the tooth in order to provide retention and resistance form, as well as protect the tooth from fracture” (Yonker, Rubinstein, Nidetz, 2011)

Most of the published articles, based on

in vivo and in vitro data, suggest that a 2

mm ferrule is best for improving resistance

to fracture with significant decreases when the ferrule is 1 mm or nonexistent (daSilva,

et al., 2010; deLima, et al., 2009; Hu, et al., 2005)

However, it is not only the height of the remaining dentin that is critical for creating the ferrule, but just as important is the width

of the remaining dentin and the number of

walls

As shown in Figures 7 and 8, there is

a drastic difference in outcomes when preparing a ferrule in a modestly flared canal versus a wide flare As can be seen, when a wide flare exists, the preparation

of a ferrule actually removes the dentinal lateral walls, creating a standalone core that essentially has no ferrule at all It is important to note here that glass ionomer cements and resin modified glass ionomers lack the physical properties to function as

a core material (Gateau, Sabek, Dailey, 2001; Mollersten, Lockowandt, Linden, 2002)

Clinical guidelines

In their article on “Rethinking the ferrule”,

Figure 6A: The common esthetic failure when using metallic posts with discoloration of the tooth structure as well as the gingival collar

Figure 6B: The result of placing a light transmitting fiber post with a translucent ceramic

CONTINUING EDUCATION

Jotkowitz, et al., (2010) provide one of

the best regression analyses and clinical

guidelines in the literature, evaluating

the effects of the height, number of walls

remaining, thickness of the walls, and

whether a mesial-distal or buccal-lingual

wall is remaining in relationship to the

functional stresses involved

A simple example would be the

difference of losing a lingual wall on an

upper central, – even if three walls remain

– which can be catastrophic due to the

torque placed on the lingual in function,

as opposed to losing an interproximal wall

that has little weakening effect when lingual

stress is applied Their conclusion is that

no ferrule equals unrestorable

“Clinical protocols should feature

well-defined inclusion criteria, including

delineation of the number of residual

coronal walls, for a clearer assessment

of the influence of the remaining tooth

structure on treatment outcomes” (Ferrari,

et al., 2012) As the number of remaining

walls decrease, the fracture resistance

decreases when no post is used, but the

fracture resistance is increased significantly

when fiber posts are placed – except when

there is no wall left (Nam, et al., 2010)

“The success rate for all posts decreases drastically in the absence a residual coronal wall” (Ferrari, et al., 2012)

The literal definitions of reinforcement from various sources include:

• A device designed to provide additional strength

is insufficient structure left to retain a core/crown, and that metal posts do not reinforce the root (Sorensen, Engleman, 1990; Caputo, Standlee, 1976; Sorensen, Martinoff, 1984; Assif, Gorfil, 1994)

Retrospectively, looking at research on endodontically treated teeth utilizing metal posts certainly supports this finding (Trope, Maltz, Tronstad, 1985; Guzy, Nichols, 1979)

However, more recent research articles and publications are creating a body of work that fiber posts do indeed make the root more resistant to fracture and may

strengthen the root

What follows is only a partial list with short summaries of some of the more recent relevant studies supporting the notion of reinforcement by using fiber posts

Reinforcement

D’Arcangelo, et al., (2008) studied the fracture resistance and deflection of teeth restored with a fiber post, and prepared for veneers Seventy-five human maxillary central incisors with similar anatomic crowns were included: no preparation, veneer preparation, endodontic access filled with composite, endodontic access with composite and veneer preparation, and fiber post placement (RTD Endo Light-Post) followed by veneer preparation All specimens were thermo-cycled and submitted to fracture strength tests by using a displacement measurement system

Preparation for veneers increased the deflection values of the specimens, but the fiber-reinforced post restoration with veneer preparations did not show statistically significant differences from the intact unprepared incisor

When investigating the fracture resistance and failure mode of premolars restored with composite resin and various prefabricated posts, Hajizadeh, et al., (2009) utilized 60 extracted teeth with four subgroups: no cavity preparation, endodontics with an MOD and no post, endodontics with a DT Light-Post (RTD) and MOD, and the last group with endodontics, Filpost (Filhol Dental, UK) and an MOD composite restoration The teeth restored with the DT Light-Post and composite were as strong as the control (the unprepared tooth) and stronger than those teeth restored with composite alone without a post, and those restored with

a titanium post and composite In the DT Light-Post group, 86% of the fractures were

“restorable,” which was much higher than any of the other three groups According

to the authors: “There is growing evidence that fiber posts provide the additional benefit of increased fracture resistance.”

The effect of placing fiber posts under zirconia-ceramic crowns was studied by Salameh, et al., (2008) Ninety mandibular second molars were divided into three test groups representing various extents

of coronal damage, endodontically accessed and obturated with warm vertical condensation Half of the specimens were

Figure 7: The typical result of creating a full crown with

a ferrule in a moderately tapered endodontic access

CONTINUING EDUCATION

restored with composite, the other half

with a translucent FRC post (Rely-X™ Fiber

Post, 3M™ ESPE™) with a composite core

The insertion of the fiber post improved

the support under the zirconia crowns,

which resulted in higher fracture loads

and favorable failure type compared to a

composite core build-up

Maccari, et al., (2003) utilized 30

single-rooted endodontically treated teeth to

evaluate the fracture resistance of different

prefabricated esthetic posts Included

in the study were Aestheti-Post (RTD),

FibreKor™ Post (Pentron), and Cosmopost

(a ceramic post system, Ivoclar Vivadent)

They summarized that the mean fracture

resistance of the glass fiber prefabricated

esthetic posts proved a higher fracture

resistance than the ceramic post, which

was less than one-half of the fiber posts

The fracture resistance and failure

pattern of endodontically treated maxillary

incisors restored with composite resin, with

and without fiber-reinforced composite

posts under different types of full coverage

crowns, was studied by Salameh, et al.,

(2008) One hundred and twenty maxillary

incisors were endodontically treated

and divided into four groups of 30 each

and further divided into two subgroups

of restoration with or without a fiber

post (Postec® Plus, Ivoclar Vivadent)

Restorations placed were PFM, Empress®

II, SR Adoro® crowns and Cercon® crowns

with all preparations including a 2 mm

ferrule

Fracture tests showed that the type of

crown was not a significant factor affecting

the fracture resistance, but the presence

of a post was The authors state that:

“Although prosthodontic textbooks do not

generally advocate the placement of fiber

posts in endodontically treated incisors,

the results of this study indicate that the

use of fiber posts in such teeth increases

their resistance to fracture and improves

the prognosis in case of fracture.”

In a study of 80 endodontically

treated maxillary premolars treated with

or without fiber posts, and MOD cavity

preparations restored with different types

of crowns including porcelain fused to

metal, lithium disilicate, fiber-reinforced

composite or zirconia crowns, Salemeh,

et al., (2007) loaded the restorations until

failure, recording the maximum breaking

loads Under vertical loading conditions,

the fracture loads of teeth restored with

fiber posts were significantly greater

than those without posts, and the fiber

posts significantly contributed to the reinforcement and strengthening of pulpless teeth by supporting the remaining tooth structure against vertical compressive stresses

There are many more studies showing the reinforcement of tooth structure with fiber posts (Schmitter, et al., 2006;

Carvalho, et al., 2005; Rosentritt, et al., 2004; Goncalves, et al., 2006; Naumann, Preuss, Frankenberger, 2007; Hayashi, et al., 2006; Hayashi, et al., 2008; Salameh,

et al., 2010; Ferrari, et al., 2007; Nothdurft,

et al., 2008)

Continual advancement

It is impossible to summarize them all, but it seems obvious that our concept of restoring endodontically treated teeth is continually advancing as new products and bonding techniques evolve Even when there are variations in the types of fiber posts used in the studies, and different cementation and adhesive protocols, there

is compelling evidence that fiber posts can reinforce tooth structure

To create balance in this overview of the literature, it must be said that there are, of course, some published scientific articles that do not show a reinforcing effect of fiber posts (Fokkinga, et al., 2005; Kreijci, et al., 2003; Abdul, et al., 2006)

In addition to the traditional definition

of mechanical reinforcement – restoring

a compromised tooth to a fracture strength equal to or greater than its original “untreated” fracture resistance – we clinicians perhaps should be more focused on the predictability of outcomes, particularly in worst-case scenarios That

is the contribution of the post versus no post, or composite only, to the remaining structures The most predominant conclusion emerging from the growing body of in vitro (and clinical) data is that failures of fiber posts in situ are more likely

to be described as “non-catastrophic” or

“repairable,” which is usually not the case with high modulus posts (Cormier, Burns, Moon, 2001; Fokkinga, Creugers, Kreulen, 2003; Le Bell-Ronnlof, et al., 2001;

periodontal ligament in distributing some

of the stresses, loading technique (vertical, horizontal, or at an angle), the type and quality of the post, the recognition of the

“secondary smear layer” and how it affects adhesion, the type of radicular dentin that

is to be bonded, the adhesive used, the light carrying or transmission capability of the post, the type of composite used to cement the post, the amount of composite lateral to the post, the filler loading of the composite, and the amount of critical dentin that is removed to place the post

“C” and “S” factor polymerization effects, curing to depth when using dual-cured composite (all dual-cured composites have a higher polymerization percentage when exposed to sufficient light), resulting

in better overall physical properties, and material incompatibilities

Fiber post restoration techniques require a meticulous protocol, and the clinician is urged to scour the literature, not only for the best fiber post available, but also the best techniques for placement Materials and techniques for fiber post restoration of endodontically treated teeth are continuously evolving with the inevitable outcome of better clinical results for our patients

Acknowledgement

The authors would like to thank Mrs Laura Delellis for her work creating the figures used in this article This article has been

reprinted with kind permission from Oral

DENTSPLY MAILLEFER / T: 1-800-924-7393 / F: 1-800-924-7389 / MAILLEFER.DENTSPLY.COM

©2013 DENTSPLY International, Inc., DENTSPLY Maillefer MAIADDAL06/13

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13_MAI_DAL_AD_EP_Full_06_13.indd 1 6/20/13 4:30 PM

Successful endodontic therapy requires

thorough knowledge of the root and the

root canal morphology (Sert, Bayirili, 1997)

According to Vertucci (2005), a major

cause of post-treatment disease is the

inability to locate, debride, and obturate

all the canals in a root canal system In

general, there is an increased prevalence of

missed roots and root canals that results in

failure of endodontic treatment (Cantatore,

et al., 2006)

According to Cleghorn, et al., (2006),

the mesiobuccal root of the maxillary

first molar has generated more research

and clinical investigation than any other

root in the oral cavity Frequent failure of

endodontic treatment in maxillary first

permanent molars is likely due to the

failure to locate and obturate the second

mesiobuccal canal (Weine, 2004) With the

advent of new instruments, equipment, and

techniques (such as operating microscopes

and ultrasonic instruments), an increase in

the number of second mesiobuccal canals

was demonstrated in clinical investigations

(Vertucci, 2005)

Cleghorn, et al., (2006), demonstrated

that two or more canals can be present in

the mesiobuccal root (with 57% of 8,339

teeth of the 34 laboratory and clinical

studies analyzed) They also reported

that a single canal at the apex of the

mesiobuccal root was found 62% of the

time, while two separate canals at the apex

were present 39% of the time In a recent

micro-CT study, it was demonstrated

that the second mesiobuccal canal was

present in 80% of the cases (24 teeth) In

42% of the specimens, it was a completely

independent root canal

In vitro and in vivo studies have also

reported the incidence of a third canal in

the mesiobuccal root of upper maxillary first molars to be between 0.5 and 9%

(Table 1) Complete deroofing of the pulp chamber, straightline access, removal of pulp calcification and dentin ledges can help with the identification of supplemental root canal systems in the mesiobuccal root (Ahmed, Saini, 2012)

The purpose of this article is to present

a case report to illustrate the clinical management of an upper first maxillary molar tooth with three mesiobuccal root canals, using the ProTaper Next system

Radiographic examination revealed that the composite restoration was placed very

close to the pulp (Figure 1)

After informed consent, it was decided

to do a root canal treatment The tooth was anesthetized and isolated with a rubber dam An initial access cavity was prepared using a diamond bur until the roof of the pulp floor was removed The access cavity was extended to ensure straightline access into the mesial and distal root canals Mesiobuccal, second mesiobuccal, distobuccal, and palatal root canal orifices were visible under magnification (Figure 2) Size 14 and 12 long shank stainless steel burs (Dentsply/Maillefer) [Figure 3],

Management of an upper first molar with three

mesiobuccal root canals

CONTINUING EDUCATION

Dr Peet van der Vyver presents a case report to illustrate the clinical management of an upper first

maxillary molar tooth with three mesiobuccal root canals, using the ProTaper Next system

Figure 1: Preoperative radiograph showing a deep composite restoration on the upper right first maxillary molar

Dr Peet van der Vyver is a part-time lecturer at the

University of Pretoria’s School of Dentistry and is in

private practice in Sandton, South Africa.

Educational aims and objectives

This clinical article aims to illustrate the clinical management of an upper first maxillary molar tooth with three mesiobuccal root canals.

Expected outcomes

Correctly answering the questions on page 32, worth 2 hours of CE, will demonstrate the reader recognizes how to manage an upper first maxillary molar tooth with three mesiobuccal root canals using the ProTaper Next system.

Figure 2: Occlusal view of the initial access cavity preparation Note the presence of a second mesiobuccal root canal

Figure 3: Size 14 and 12 long shank stainless steel burs (Dentsply/Maillefer)