Ebook Textbook of endodontics (3/E): Part 1

Textbook of

ENDODONTICS


Textbook of

ENDODONTICS
THIRD EDITION

Nisha Garg  MDS
(Conservative Dentistry and Endodontics)
Ex-Resident, Postgraduate Institute of Medical Education and Research
Chandigarh, India
Ex-Resident, Government Dental College
Patiala, Punjab, India
Presently Reader
Department of Conservative Dentistry and Endodontics
Sri Sukhmani Dental College and Hospital
Dera Bassi, Punjab, India

Amit Garg MDS
(Oral and Maxillofacial Surgery)
Ex-Resident, Government Dental College
Postgraduate Institute of Medical Sciences
Rohtak, Haryana, India
Consultant Oral and Maxillofacial Surgeon
Faridabad, Haryana, India

Foreword

Anil Chandra

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Textbook of Endodontics
First Edition: 2007
Second Edition: 2010
Third Edition: 2014
ISBN: 978-93-5090-952-2
Printed at


Dedicated to
Prisha
and
Vedaant


Contributors
Amit Garg

Consultant Oral and
Maxillofacial Surgeon
Faridabad, Haryana, India

Navjot Singh Khurana

Sandhya Kapoor Punia

Senior Lecturer
Department of Conservative Dentistry
and Endodontics
Darshan Dental College
Udaipur, Rajasthan, India

Amita

Lecturer
Department of Conservative Dentistry
and Endodontics
Government Dental College
Patiala, Punjab, India

Associate Professor 
Faculty of Dentistry
Jamia Millia Islamia
New Delhi, India

Anil Dhingra

Professor
Faculty of Dental Sciences
Institute of Medical Sciences
Banaras Hindu University
Varanasi, Uttar Pradesh, India

Nisha Garg

Senior Lecturer

Department of Conservative Dentistry
and Endodontics
National Dental College
Dera Bassi, Punjab, India

Reader
Department of Conservative Dentistry
and Endodontics
BRS Dental College and Hospital
Panchkula, Haryana, India
Professor and Head
Department of Conservative Dentistry
and Endodontics
DJ Institute of Dental
Sciences and Research
Modinagar, Uttar Pradesh, India

Bobbin Gill

Consultant Endodontist
Chandigarh, India

Jaidev Dhillon

Professor and Head
Department of Conservative Dentistry
and Endodontics
BRS Dental College and Hospital
Panchkula, Haryana, India

JS Mann

Associate Professor
Department of Conservative Dentistry
and Endodontics
Government Dental College
Patiala, Punjab, India

Manoj Hans

Reader
Department of Conservative Dentistry
and Endodontics
Vyas Dental College and Hospital
Jodhpur, Rajasthan, India

Monia Sharma

Reader
Department of Periodontics
DAV Dental College
Yamuna Nagar, Haryana, India

Neelam Mittal

Reader
Department of Conservative Dentistry
and Endodontics
Sri Sukhmani Dental
College and Hospital

Dera Bassi, Punjab, India

Poonam Bogra

Senior Professor
Department of Conservative Dentistry
and Endodontics
DAV Dental College
Yamuna Nagar, Haryana, India

RS Kang

Associate Professor
Department of Conservative Dentistry
and Endodontics
Government Dental College
Patiala, Punjab, India

Ruchi Vashisht

Reader
Department of Conservative Dentistry
and Endodontics
National Dental College
Dera Bassi, Punjab, India

Sachin Passi

Principal and Head
Department of Conservative Dentistry

and Endodontics
Sri Sukhmani Dental
College and Hospital
Dera Bassi, Punjab, India

Sanjay Miglani

Shinam Kapila Pasricha

Suresh K Saini

Reader
Department of Prosthodontics
BRS Dental College and Hospital
Panchkula, Haryana, India

Vikas Punia

Senior Lecturer
Department of Prosthodontics
Darshan Dental College
Udaipur, Rajasthan, India

Yoshitsugu Terauchi 

DDD PhD

Lecturer, Tokyo Medical and
Dental University
Japan

Foreword
It gives me immense pleasure to introduce you to the third edition of the Textbook of Endodontics. Past
several years have witnessed the publication of many new textbooks on the subject of endodontics
by well-known scholars and scientists. Several critically important paradigm shifts have occurred in
dentistry, particularly in the field of endodontics in the past decades, a shift towards the comprehensive
approach in the endodontic practice today. It is of foremost importance to put this work into the context
of the continuum of endodontic literature.
Endodontics has become so important in the last several decades that books which condense all the
techniques and treatment options are certainly looked-for. Written by the two leading authorities on this
important aspect of dentistry, Drs Nisha Garg and Amit Garg have accumulated a tremendous amount
of knowledge to summarize this important information into easy-to-read chapters. This compact yet
comprehensive work clearly portrays their efforts. The authors have invested extensive time and effort to freshly describe the
existing literature and have added interesting chapters like Endodontic Failures and Retreatment, Tooth Hypersensitivity, and
Tooth Infractions. I am sure the new edition of the book will be equally appreciated by the undergraduate and postgraduate
students as well as the researchers.
I am delighted and honored to introduce and recommend the book, which will effectively bridge the gap between the
scientific esoteric and practitioner’s daily need for relevant knowledge, and will become one of the most significant steps in
understanding the subject of endodontics. 

Anil Chandra
Professor
Department of Conservative Dentistry and Endodontics
King George’s Medical University
Lucknow, Uttar Pradesh, India


Preface to the Third Edition
In presenting the third edition of the Textbook of Endodontics, we would like to express our appreciation in the kindly manner

in which the earlier editions were accepted by dental students and professionals across the country.
The scope of the third edition of this book is as earlier to be simple yet comprehensive Textbook of Endodontics that serves
as an introductory for dental students and a refresher source for general practitioners. The book attempts to incorporate most
recent advances in endodontics while at the same time not losing the sight of basics, therefore, making the study of endodontics
easier and interesting.
In an attempt to improve the book further, many eminent personalities were invited to edit, write and modify the important
chapters in form of text and photographs. We would especially thank Dr Jaidev Dhillon, Dr Anil Dhingra, Dr Neelam Mittal,
Dr Poonam Bogra, Dr Sachin Passi, and Dr Manoj Hans for providing us clinical case-photographs and radiographs for better
understanding of the subject.
We are indebted to Dr Poonam Bogra for writing an important chapter Biofilm in Endodontics for the book and editing
chapters, Access Cavity Preparation, Cleaning and Shaping of Root Canal System, Irrigation and Intracanal Medicaments.
We fall lack of words to thank Dr Sri Rekha for critically evaluating the chapter; Working Length Determination, Endodontic
Instruments and Management of Traumatic Injuries.
We are thankful to Dr Sanjay Miglani for modifying chapter Internal Anatomy, Dr Navjot Singh Khurana for editing chapter
Management of Traumatic Injuries, Dr Monia Sharma for Endodontic Periodontal Lesions, Dr Ruchi Vashisht for Obturation
of Root Canal System and Surgical Endodontics, Dr Shinam Pasricha for Tooth Infractions and Tooth Resorption, Drs Amita
and Suresh Saini for Postendodontic Restorations, Dr Bobbin for Flare-ups, Drs Sandhya Kapoor Punia and Vikas Punia for
editing Geriatric Endodontics and Tissue Engineering.
We are specially thankful to Yoshitsugu Terauchi for sharing his new device for removal of the fractured instrument.
We are thankful to Dr RS Kang and Dr JS Mann for their constant support, motivation and encouragement. We are also
thankful to Dr Arundeep Singh, Dr Rahul Jain and Dr Gaurav Aggarwal for providing photographs and radiographs for the
book. Also thankful to Dr Shaweta for helping us in sorting out the MCQs for the book.
We offer our humble gratitude and sincere thanks to Mr Avtar Singh (Chairman), and Mr Daman Jeet Singh, Sri Sukhmani
Dental College (SSDC), Dera Bassi, Punjab, India, for providing healthy and encouraging environment for our work.
We would like to express our thanks to staff of Department of Conservative Dentistry and Endodontics, Sri Sukhmani Dental
College, Dera Bassi, Punjab, India, Dr Sachin Passi, Dr Rajnish Kumar and Dr Rahul Jain for their ‘ready to help’ attitude,
constant guidance and positive criticism which helped in improvement of the book.
It is hoped that all these modifications will be appreciated and render the book still more valuable basis for endodontic
practice.
We are thankful to Shri Jitendar P Vij (Group Chairman), Mr Ankit Vij (Managing Director), Mr Tarun Duneja (DirectorPublishing), Mr KK Raman (Production Manager), Mr Sunil Kumar Dogra (Production Executive), Mr Neelambar Pant

(Production Coordinator), Mr Manoj Pahuja (Senior Graphic Designer), Mr Binay Kumar (Proofreader), Mr Chandra Dutt
(Typesetter) and staff of M/s Jaypee Brothers Medical Publishers (P) Ltd, New Delhi, India, for showing personal interest and
trying to the level best to bring the book in present form.

Nisha Garg
Amit Garg


Preface to the First Edition
The amount of literature available in dentistry today is vast. Endodontics being no exception. However, during both our
graduation as well as postgraduation, we always felt the need for a book which would help us to revise and update our
knowledge. When we were doing undergraduation, there were no Indian authored books on endodontics. We were thus
motivated to frame a specialized, precise, concise, easy to read and remember yet, up-to-date Textbook of Endodontics.
The line diagrams are in an expressive interpretation of endodontic procedures, which are worked upon and simplified
to render them more comprehensive and comparable with real photographs. These illustrations (around 1200) are easy to
remember and reproduce during examinations.
Emphasis is laid upon the language which is simple, understandable and exclusively designed for undergraduates,
postgraduates, general practitioners and teachers in the field.
It took us more than three years to accomplish the arduous task of writing this book. This thrust for knowledge led us to link
everywhere, where we could Medline journals, books and more.
Nevertheless, a never-ending approach and internal craving of mind and soul finally resulted in publication of the book.
God perhaps gave us some ability and showered his light on us, guiding us for this task.
Till the last week before the publication of the book, we were frantically looking for loopholes, missing information and any
important updates we might have missed out. To the best of our knowledge, we did everything we could. But for knowledge,
one life is not enough. The sky is the limit.
We await the response of this first edition, which would improve us in the next editions to come.

Nisha Garg
Amit Garg

Contents
1. Introduction and Scope of Endodontics

1

History of Endodontics 1; Modern Endodontics 1; Patient Education 3

2. Pulp and Periradicular Tissue

7

Development of Dental Pulp  7;  Histology of Dental Pulp  8;  Supportive Elements  11;
Innervation of Pulp  13;  Anatomy of Dental Pulp  15;  Pulp Chamber  15;  Root Canal  15;
Functions of Pulp  17;  Age Changes in the Pulp  18;  Pulpal Calcifications/Pulp Stones/
Denticles 18; Calcific Metamorphosis 19; Periradicular Tissue 19

3. Pathologies of Pulp and Periapex

22

Pulp Pathologies  22;  Etiology of Pulpal Diseases  23;  Progression of Pulpal
Pathologies  24;  Diagnostic Aids for Pulpal Pathology  25;  Classification of Pulpal
Pathologies 26; Barodontalgia/Aerodontalgia 27; Reversible Pulpitis/Hyperemia/
Hyperactive Pulpalgia 27; Irreversible Pulpitis 28; Chronic Pulpitis 30; Internal
Resorption 32; Pulp Necrosis 32; Pulp Degeneration 34; Periradicular
Pathologies 35; Periapex Pathologies 36; Etiology of Periradicular Diseases 36; Diagnosis
of Periradicular Pathologies  37;  Classification of Periradicular Pathologies  38;  Acute
Apical Periodontitis  39;  Acute Apical Abscess  39;  Phoenix Abscess/Recrudescent
Abscess 41; Periapical Granuloma 42; Radicular Cyst/Cystic Apical Periodontitis 44;

Chronic Alveolar Abscess  46;  Persistent Apical Periodontitis  49;  External Root
Resorption  49;  Diseases of Periradicular Tissue of Nonendodontic Origin  49

4. Endodontic Microbiology

51

Portals of Entry for Microorganisms   51;  Classification of Microorganisms  53;
Microbial Virulence and Pathogenicity  54;  Factors Influencing the Growth and Colonization of
Microorganisms  55;  Microbial Ecosystem of the Root Canal  55;
Types of Endodontic Infections  56;  Identification of the Bacteria  57;  How to Combat
Microbes in the Endodontic Therapy?  59

5. Biofilm in Endodontics

61

Stages of Biofilm Formation  61;  Types of Endodontic Biofilm  61;  Ultrastructure of
Biofilm  62;  Microbes in Endodontic Biofilms   62;  Methods to Eradicate Biofilms   63

6. Rationale of Endodontic Treatment
Theories of Spread of Infection  65;  Culprit of Endodontic Pathology  65;  Portals for
Entry of Microorganisms   66;  Inflammation   66;  Nonspecific Mediators of Periradicular
Lesions  68;  Antibodies (Specific Mediators of Immune Reactions)  71;  Role of Immunity in
Endodontics  71;  Endodontic Implications (Pathogenesis of Apical Periodontitis as Explained
by Fish)  71;  Kronfeld’s Mountain Pass Theory  72;  Rationale of Endodontic Therapy  73

65

xvi  Textbook of Endodontics

7. Diagnostic Procedures

74

Case History  74;  Pulp Vitality Tests  82;  Recent Advances in Pulp Vitality
Testing  85;  Diagnostic Findings  87;  Role of Radiographs in Endodontics  87;
Digital Radiography  91;  Digital Dental Radiology  91;  Phosphor Imaging System  93

8. Differential Diagnosis of Orofacial Pain

95

Pain 95; Diagnosis 95; Orofacial Pain 96; Sources of Odontogenic Pain 96;
Pulpal Pain  97;  Periodontal Pain  98;  Sources of Nonodontogenic Pain  99

9. Case Selection and Treatment Planning

103

Endodontic Therapy 103; Contraindications of Endodontic Therapy 104;
Treatment Planning  105;  Medical Conditions Influencing Endodontic Treatment
Planning 106; Sequence of Treatment Delivery 107

10. Asepsis in Endodontics

109

Rationale for Infection Control 109; Cross-infection 109; Objective

of Infection Control  110;  Universal Precautions  110;  Classification of
Instruments  112;  Instrument Processing Procedures/Decontamination
Cycle 112; Disinfection 118; Antiseptics  119; Infection Control Checklist 120

11. Isolation of Teeth

122

Isolation with Rubber Dam  122;  Classification of Rubber Dam Clamps  124

12. Pharmacology in Endodontics

131

Anxiety Control 131; Pain Control 132; Intrapulpal Injection 139;
Infection Control  141;  Guidelines for Antibiotic Prophylaxis  143

13. Endodontic Instruments

145

Classification of Endodontic Instruments  145;  Group I Hand-operated
Instruments  146;  Group II Nonrotary Endodontic Instruments  152;  Group III Rotary
Endodontic Instruments used with a Handpiece  155;  Various Rotary Nickel Titanium
System 157; Profile System 158; Greater Taper File 158; Protaper File  158; Quantec File
System 160; Light Speed System 160; K3 Rotary File System  161;  HERO 642  161;  Race Files
(Reamers with Alternating Cutting Edges)  161;  Real World Endo Sequence File  162;  Wave
One System  162;  Instrument Deformation and Breakage  163;  Instruments used for Filling
Root Canals  166

14. Internal Anatomy

169

Pulp Cavity  169;  Common Canal Configuration  171;  Methods of Determining Pulp
Anatomy  172;  Variations in the Internal Anatomy of Teeth  174;  Factors Affecting Internal
Anatomy 180; Individual Tooth Anatomy 180; C-Shaped Canals 191; Classification of
C–Shaped Root Canals  191

15. Access Cavity Preparation
Instruments for Access Cavity Preparation  198;  Guidelines for Access Cavity
Preparation   199;  Access Cavity of Anterior Teeth  201;  Access Cavity Preparation for
Premolars  203;  Access Cavity Preparation for Maxillary Molars  204;  Access Cavity Preparation
for Mandibular Molars  205;  Clinical Managing Difficult Cases for Access Opening  206

196


Contents  xvii

16. Irrigation and Intracanal Medicaments

211

Ideal Requirements for an Irrigant  211;  Functions of Irrigants  212;  Factors that Modify
Activity of Irrigating Solutions   212;  Commonly used Irrigating Solutions  213;  Choice of an
Irrigant Solution  213; Normal Saline 213; Sodium Hypochlorite 214; Urea  216; Hydrogen
Peroxide 216; Urea Peroxide 217; Chlorhexidine  217; Chelating Agents 218; Ultrasonic
Irrigation   220;  Newer Irrigating Solutions   221;  Method of Irrigation   223;  Endovac (Apical
Negative Pressure Irrigation System)  225;  Intracanal Medicaments  227;  Characteristics of

Intracanal Medicaments   227;  Placement of Intracanal Medicament  232

17. Working Length Determination

235

Significance of Working Length  236;  Different Methods of Working Length
Determination  238;  Radiographic Method of Working Length Determination  238;
Grossman Method/Mathematical Method of Working Length Determination  239;
Electronic Apex Locators  240

18. Cleaning and Shaping of Root Canal System

246

Objectives of Biomechanical Preparation  247;  Different Movements of
Instruments  249;  Basic Principles of Canal Instrumentation  251;  Techniques of Root Canal
Preparation 252; Standardized Preparation Technique (Conventional Technique) 253;
Step Back Technique/Telescopic Canal Preparation/Serial Root Canal Preparation  253;
Modified Step Back Technique  257;  Passive Step Back Technique  257;  Coronal to
Apical Approach Technique  258;  Step Down Technique  259;  Crown Down Pressureless
Technique  259;  Hybrid Technique of Canal Preparation (Step Down/Step Back)  262;
Double Flare Technique  262;  Modified Double Flared Technique   262;  Balanced Force
Technique  263;  Reverse Balanced Force Preparation   264;  Types of Crown Down Hand
Instrumentation Techniques   264;  Modified Manual Step Down Technique  264;  Profile
GT (Greater Taper) Technique 264; Quantec Instrument Technique 265; Protaper
Files  265;  Engine Driven Preparation with NiTi Instruments 267; Profile System 267; 
Greater Taper Files (GT Files)  268;  Light Speed System  268;  K3 Rotary File System  270;
Real World Endo Sequence File  270;  HERO 642  270;  Wave One File System  271;
Canal Preparation using Ultrasonic Instruments  272;  Canal Preparation using Sonic

Instruments  273;  Laser Assisted Root Canal Therapy  274;  Evaluation Criteria of Canal
Preparation  274;  Special Anatomic Problems in Canal Cleaning and Shaping  275

19. Obturation of Root Canal System

282

Timing of Obturation  284;  Extent of Root Canal Filling  285;  Materials
used for Obturation  286;  Methods of Sealer Placement  301;  Obturation
Techniques  301;  Armamentarium for Obturation 302;  Lateral Compaction
Technique  302;  Variation of Lateral Compaction Technique   305;  Chemical Alteration
of Gutta-percha  306;  Vertical Compaction Technique  309;  System B: Continuous
Wave of Condensation Technique  311;  Lateral/Vertical Compaction of Warm Guttapercha 312; Sectional Method of Obturation/Chicago Technique 313; McSpadden
Compaction/Thermomechanical Compaction of the Gutta-percha   313;  Thermoplasticized
Injectable Gutta-percha Obturation  313; Solid Core Carrier Technique   315;  Obturation with
Silver Cone 318; Apical Third Filling  318; Postobturation Instructions 321; Repair following
Endodontic Treatment  322

20. Single Visit Endodontics
Advantages of Single Visit Endodontics  323;  Disadvantages of Single Visit
Endodontics  323;  Criteria of Case Selection   323;  Contraindications of Single Visit
Endodontics 325

323


xviii  Textbook of Endodontics

21. Mid Treatment Flare-ups in Endodontics

326

Etiology   326;  Mechanisms for Flare-ups  328;  Clinical Conditions Related to
Flare-up 330; Management of Flare-ups 331

22. Endodontic Emergencies

335

Diagnosis and Treatment Planning  335;  Pretreatment Endodontic
Emergencies  336;  Conditions Requiring Emergency Endodontic
Treatment 337; Intratreatment Emergencies 341; Postobturation Emergencies 343

23. Endodontic Failures and Retreatment

345

Evaluation of Success of Endodontic Treatment  345;  Causes of the Endodontic
Failures  346;  Case Selection for Endodontic Retreatment  351;  Steps of Retreatment  352

24. Procedural Accidents

364

Inadequately Cleaned and Shaped Root Canal System  364;  Instrument
Separation  368;  Deviation from Normal Canal Anatomy  373;  Inadequate Canal
Preparation 375; Perforation 377; Obturation Related 383; Vertical Root
Fracture 384; Instrument Aspiration 385

25. Surgical Endodontics

386

Contraindications 387; Presurgical Considerations 388; Incision and
Drainage 388; Periradicular Surgery 389; Flap Designs and Incisions 391; Principles and
Guidelines for Flap Designs  391;  Full Mucoperiosteal Flaps  391;  Limited Mucoperiosteal
Flaps  392;  Flap Design Consideration in Palatal Surgery  393;  Flap Reflection and
Retraction  394;  Hard Tissue Management  395;  Principles of Surgical Access to
Root Structure  395; Periradicular Curettage  396;  Root-end Resection (Apicoectomy,
Apicectomy) 397; Root-end Preparation 400; Retrograde Filling 402; Reapproximation
of the Soft Tissue 404; Replantation 404; Transplantation 405; Root Resection/
Amputation 405; Bicuspidization/Bisection 405; Endodontic Implants 409;
Postsurgical Care 409; Suturing  411; Postsurgical Complications 411

26. Endodontic Periodontal Relationship

413

Pathways of Communication between Pulp and Periodontium  414;  Impact of
Pulpal Diseases on the Periodontium  416;  Impact of Periodontal Disease on Pulpal
Tissue  417;  Etiology of Endodontic-periodontal Problems  417;  Classification of Endodonticperiodontal Lesions  417;  Diagnosis of Endodontic-periodontal Lesions  419;  Primary
Endodontic Lesions   420;  Primary Endodontic Lesion with Secondary Periodontal
Involvement  421;  Primary Periodontal Lesions  422;  Primary Periodontal Lesions with
Secondary Endodontic Involvement  422;  Independent Endodontic and Periodontal Lesions
which do not Communicate  426;  True Combined Endo-Perio Lesions  426

27. Restoration of Endodontically Treated Teeth
Importance of Coronal Restoration  428;  Factors Making Endodontically Treated Teeth
Different from Vital Teeth  429;  Restorative Treatment Planning for Endodontically
Treated Teeth  430;  Components of the Restored Tooth  432;  Factors to be Considered

while Planning Post and Core  439;  Preparation of the Canal Space and the
Tooth 447; Core 450; Custom-made Post 451; Core Fabrication  452; Investing and
Casting 452; Evaluation  452; Cementation  452

428


Contents  xix

28. Management of Traumatic Injuries

454

Classification of Dentofacial Injuries  454;  Examination of Traumatic Injuries  455;
Crown Infraction 457; Crown Fracture 458; Complicated Crown Fracture 459;
Crown Root Fracture 463; Root Fracture 467; Luxation Injuries 471; Assessment of
Traumatic Injuries  477;  Prevention of Traumatic Injuries  478

29. Pulpal Response to Caries and Dental Procedure

480

Response of Pulp to Dental Caries  481;  Response of Pulp to Tooth Preparation  482; 
Response of Pulp to Local Anesthetics  485;  Effect of Chemical Irritants on Pulp  486;
Dentin Sterilizing Agents  486;  Cavity Liner and Varnishes  486;  Response
of Pulp to Restorative Materials  486;  Restorative Resins  488;  Effects of Pin
Insertion  488;  Impression Material  489;  Effects of Radiations on Pulp  489;  Effect of
Heat from Electrosurgery  490;  Effect of Lasers on Pulp  490;  Defense Mechanism of
Pulp  490;  Prevention of Pulpal Damage due to Operative Procedure  491;  How does Pulp
Recover? 491

30. Management of Discolored Teeth

492

Classification of Discoloration 492; Bleaching 496; Contraindications for
Bleaching   496;  Bleaching Agents  497;  Home Bleaching Technique/Night Guard
Bleaching 497; In-Office Bleaching 499; Bleaching of Nonvital Teeth 502; Effects of
Bleaching Agents on Tooth and its Supporting Structures  505

31. Tooth Resorption

507

Classification of Resorption  507;  Cells Involved in Tooth Resorption  508;  Mechanism of Tooth
Resorption 509; Factors Regulating Tooth Resorption 509; Internal Resorption 510; External
Root Resorption  516;  Cervical Root Resorption (Extracanal Invasive Resorption)  522

32. Tooth Infractions

524

Tooth Infractions  524;  Vertical Root Fracture  529

33. Tooth Hypersensitivity

531

Mechanism of Dentin Sensitivity  531;  Incidence and Distribution of Dentin
Hypersensitivity 532; Etiology and Predisposing Factors 532; Differential

Diagnosis 534; Diagnosis 534; Treatment Strategies 534

34. Pediatric Endodontics

538

Anatomy of Primary Teeth 538; Pulp Treatment Procedures 540; Pulpotomy 542;
Pulpectomy for Primary Teeth 545; Apexification 548; Mineral Trioxide Aggregate 551

35. Geriatric Endodontics

554

Age Changes in the Teeth  554;  Endodontics in Geriatric Patients  555;
Diagnosis and Treatment Plan  558

36. Lasers in Endodontics
History 561; Classification of Laser 562; Laser Physics 562; Type of Lasers 564;
Laser Interaction with Biological Tissues  564;  Laser Safety in Dental Practice  565;
Soft and Hard Tissue Applications of Lasers in Dentistry  566

561


xx  Textbook of Endodontics

37. Magnification

569

Loupes 569; Surgical Operating Microscope 570; Endoscope 572; Orascope 572

38. Ethics in Endodontics

574

Principles of Ethics  574;  Root Canal Ethics  574;  Informed Consent  575;
Dental Negligence  575;  Malpractice and the Standard of Care  576;  Abandonment  577;
Malpractice Cases  577

39. Tissue Engineering

579

Strategies of Stem Cell Technology  579;  Triad of Tissue Engineering  579;  Dental Pulp
Stem Cells  582;  Stem Cells from Human Exfoliated Deciduous Teeth  582;  Periodontal
Ligament Stem Cells  582;  Stem Cell Markers  582;  Morphogens/Signaling Molecules  582; 
Scaffold/Matrix 583; Approaches to Stem Cell Technology 583; Revascularization
to Induce Apexification/Apexogenesis in Infected Non-vital Immature
Tooth 586; Apexification 586; Pulp Revascularization 586; Pulp Revascularization in
Immature Teeth   587;  Mechanism of Revascularization  587;  Advantages of
Revascularization Procedure  588;  Limitations of Revascularization Procedure  588

Index591


1

Introduction and Scope of
Endodontics

 History of Endodontics

 Modern Endodontics

INTRODUCTION
Endo is a Greek word for “Inside” and Odont is Greek word
for “Tooth”. Endodontic treatment deals inside of the tooth.
Endodontics is the branch of clinical dentistry associated
with the prevention, diagnosis and treatment of pathosis of the
dental pulp and their sequelae.
Thus, the main aim of the endodontic therapy involves to:
• Maintain vitality of the pulp.
• Preserve and restore the tooth with damaged and necrotic
pulp.
• Preserve and restore the teeth which have failed to the
previous endodontic therapy.
Thus we can say that the primary goal of endodontic
therapy is to create an environment within the root canal
system which allows the healing and continued maintenance
of the health of the periradicular tissue.
Endodontics has been defined as art as well as science of
clinical dentistry; because in spite of all the factual scientific
foundation on which the endodontics is based, to provide an
ideal endodontic treatment is an art in itself.
Before understanding what is root canal therapy, how and
when it is performed and other facts regarding endodontic
therapy, we should be familiar with the history of endodontics.

HISTORY OF ENDODONTICS (TABLE 1.1)
Endodontics has been practiced as early as second or third

century BC. The history of endodontics begins in 17th century
and since then many advances, developments and research
work has been done continuously.
Advances in endodontics have been made continuously,
especially after Pierre Fauchard (1678-1761) [Founder of
modern dentistry] described the pulp very precisely in his
textbook “Le Chirugien Dentiste”.
Latter in 1725, Lazare Rivere introduced the use of clove
oil as sedative and in 1746, Pierre Fauchard demonstrated
the removal of pulp tissue. Dr Grossman, the pioneer of
endodontics divided the evolution of endodontics in four eras
from 1776 to 1976, each consisting of 50 years.

 Patient Education

Prescience
Age of discovery
Dark age
The renaissance
Innovation era

:
:
:
:
:

1776 to 1826
1826 to 1876
1876 to 1926

1926 to 1976
1977 till date

Prescience (1776 to 1826): In this era, endodontic therapy
was concerned with the crude modalities like abscesses were
being treated with poultices or leeches and pulps were being
cauterized using hot instruments.
Age of discovery (1826 to 1876): In this era, the development
of anesthesia, gutta-percha and barbed broaches happened.
The medications were created for treating pulpal infections
and the cements and pastes were discovered to fill them.
Dark age (1876 to 1926): In spite of introduction of X-rays
and general anesthesia, extraction of tooth was the choice
of treatment than endodontics because theory of the focal
infection was main concern at that time.
The renaissance (1926 to 1976): In this era, endodontics was
established as science and therapy, forming its golden era. It
showed the improvement in anesthesia and radiographs for
better treatment results. The theory of focal infection was also
fading out, resulting in more of endodontics being practiced.
In 1943, because of growing interest in endodontics, the AAE,
that is, the American Association of Endodontists was formed.
Innovation era: It is the period from 1977 onwards in
which tremendous advancements at very fast rate are being
introduced in the endodontics. The better vision, better
techniques of biomechanical preparations, and obturation
are being developed resulting in the simpler, easier and faster
endodontics with more predictable results.
Also the concept of single visit endodontics is now globally
accepted in contrast to multiple visits.

MODERN ENDODONTICS
As we have seen, over the years, there has been a great improve­
ment in the field of endodontics. Many researches have been


2  Textbook of Endodontics
Table 1.1: History of endodontics
1725

Lazare Riviere

Introduced clove oil for sedative property

1728

Pierre Fauchard

First described the pulp tissue

1746

Pierre Fauchard

Described removal of pulp tissue

1820

Leonard Koecker

Cauterized exposed pulp with heated instrument and protected it with lead foil

1836

S Spooner

Suggested arsenic trioxide for pulp devitalization

1838

Edwin Maynard

Introduced first root canal instrument

1847

Edwin Truman

Introduced gutta-percha as a filling material

1864

SC Barnum

Prepared a thin rubber leaf to isolate the tooth during filling

1867

Bowman

Used gutta-percha cones for filling of root canals

1867

Magitot

Use of electric current for testing pulp vitality

1879

GA Mills

Etiologic factor of pulp sequelae was lack of vitality in the tooth

1885

Lepkoski

Substituted formations for arsenic to dry the nonvital pulp

1890

Gramm

Introduced gold plated copper points for filling

1891

Otto Walkhoff

Introduced camphorated chlorophenol as a medication

1895

Roentgen

Introduced formocresol

1914

Callahan

Introduction of lateral compaction technique

1918

Cluster

Use of electrical current for determination of working length

1920

BW Hermann

Introduced calcium hydroxide

1936

Walker

Sodium hypochlorite

1942

Suzuki

Presented scientific study on apex locator

1944

Johnson

Introduced profile instrument system

1957

Nygaard Ostby

Introduced EDTA

1958

Ingle and Levine

Gave standardizations and guidelines for endodontic instruments

1961

Sparser

Walking bleach technique

1962

Sunanda

Calculated electrical resistance between periodontium and oral mucous
membrane

1967

Ingle

Introduced standardized technique

1971

Weichman Johnson

Use of lasers

1979

Mullaney et al.

Use of step-back technique

1979

McSpadden

McSpadden technique (Thermomechanical compaction)

1980

Marshall and Pappin

Introduction of Crown down technique

1985-86

Roane, Sabala and Powell

Introduction of balanced force technique

1988

Munro

Introduced first commercial bleaching product

1989

Haywood and Heymann

Nightguard vital bleaching

1993

Torabinejad

Introduced MTA (Mineral trioxide aggregate)

2004

Pentron clinical laboratory

Introduced Resilon

conducted and papers are being presented regarding the
advances, modifications and change in attitude regarding
endodontic therapy. In the past two decades, extensive studies
have been done on microbial flora of pulp and the periapical
tissue. The biological changes, role of innate and acquired
immunological factors are being investigated in dental pulp
after it gets infected, healing of the periapical tissue after
undergoing root canal therapy is also being investigated.

Various ways to reduce the levels of microbial infection,
viz. chemical, mechanical and their combination have led to
development of newer antimicrobial agents and techniques
of biomechanical preparation for optimal cleaning and
shaping of the root canals.
To increase the efficiency of root canal instrumentation,
introduction of engine driven rotary instruments is made.
Introduction of Nickel Titanium multitapered instruments


Introduction and Scope of Endodontics  3
with different types of cutting tips have allowed the better,

easier and efficient cleaning and shaping of the root canals.
The advent of endomicroscope in the field of endodontics
has opened the great opportunities for an endodontist. It
is used in every phase of the treatment, i.e. from access
opening till the obturation of root canals. It makes the images
both magnified and illuminated, thus helps in making the
treatment more predictable and eliminating the guess work.
Introduction of newer obturation systems like system
B Touch and heat have made it possible to fill the canal three
dimensionally. Material like mineral trioxide aggregate (MTA),
a root canal repair material has made the procedures like
apexification, perforation repair to be done under moist field.
Since endodontics is based on the principles of inflammation,
pulp and periapical disease processes and treatments
available, the future of endodontics lies in redefining the
rationale of endodontic therapy using newer modalities and
to meet the set of standards for excellence in the future.
Scope of endodontics (Fig. 1.1)
•  Vital pulp therapy (pulp capping, pulpotomy)
•  Diagnosis and differential diagnosis of oral pain
•  R
 oot canal treatment of teeth with or without periradicular
pathology of pulpal origin
•  Surgical management of pathology resulting form pulpal disease
•  Management of avulsed teeth (replantation)
•  Endodontic implants
•  Root end resections, hemisections and root resections
•  Retreatment of teeth previously treated endodontically
•  Bleaching of discolored teeth
•  Coronal restorations of teeth using post-and-cores.

PATIENT EDUCATION
Most of the patients who need endodontic treatment, are often
curious and interested regarding the treatment. Following
information should be given to the patients in anticipation of
frequently asked questions:

Who Performs an Endodontic Therapy?
Generally, all dentists receive basic education in endodontic
treatment but an endodontist is preferred for endodontic
therapy. General dentists often refer patients needing
endodontic treatment to endodontists.

Who is an Endodontist?
An endodontist is a dentist who undergoes a special training in
diagnosing and treating the problems associated with inside
of the tooth. To become specialists, they complete dental
school and an additional two or more years of advanced
training in endodontics. They perform routine, difficult,
complex endodontic procedures (including retreatment of
previous root canals that have not healed completely) and
endodontic surgeries.

What is Endodontics?
Endodontics is the diagnosis and treatment of inflamed
and damaged pulps. Teeth are composed of protective hard
covering (enamel, dentin and cementum) encasing a soft
living tissue called pulp (Fig. 1.2). Pulp contains blood vessels,
nerves, fibers and connective tissue. The pulp extends from the
crown of the tooth to the tip of the roots where it connects to

the tissues surrounding the root. The pulp is important during
a tooth’s growth and development. However, once a tooth is
fully mature it can survive without the pulp, because the tooth
continues to be nourished by the tissues surrounding it.

How does Pulp become Damaged?
Number of ways which can damage the pulp include tooth
decay (Figs 1.3 and 1.4), gum diseases, injury to the tooth by
accident.

Why do I Feel Pain?
When pulp becomes infected, it causes increased blood flow
and cellular activity, and pressure cannot be relieved from
inside the tooth. This causes pain. Pulp can even die without
causing significant pain.

How can You Tell if Pulp is Infected?
Fig. 1.1  The scope of endodontology

When pulp gets inflamed, it may cause toothache on taking
hot or cold, spontaneous pain, pain on biting or on lying
down. A damaged pulp can also be noticed by drainage,


4  Textbook of Endodontics

Fig. 1.2  Normal anatomy of a tooth showing enamel,
dentin, cementum and pulp
Fig. 1.5  Tooth with infected pulp and abscess formation

swelling, and abscess at the root end (Fig. 1.5). Sometimes,
however, there are no symptoms.

Why do I need Root Canal Therapy?

Fig. 1.3  Tooth decay causing damage to pulp

Because tooth will not heal by itself, the infection may
spread around the tissues causing destruction of bone and
supporting tissues (Fig. 1.6). This may cause tooth to fall
out. Root canal treatment is done to save the damaged pulp
by thorough cleaning and shaping of the root canal system
and then filling it with gutta-percha (rubber like) material to
prevent recontamination of the tooth. Tooth is permanently
restored with crown with or without post.

What are Alternatives to Root Canal Therapy?
If tooth is seriously damaged and its support is compromised,
then extraction is only alternative.

What is Root Canal Procedure?

Fig. 1.4  Radiograph showing carious exposure of pulp

Once the endodontic therapy is recommended, your
endodontist will numb the area by injecting local anesthetic.
After this a rubber sheet is placed around the tooth to isolate
it. Then the opening is made in the crown of the tooth and
very small sized instruments are used to clean the pulp from
pulp chamber and root canals (Fig. 1.7). After thorough

cleaning and shaping of root canals (Fig. 1.8), they are filled
with rubber like material called gutta-percha, which will
prevent the bacteria from entering this space again (Figs 1.9
and 1.10).


Introduction and Scope of Endodontics  5

Fig. 1.6  Radiograph showing periapical lesion
due to carious exposure

Fig. 1.9  Obturation of root canal system

Fig. 1.7  Cleaning and shaping of root canal system

Fig. 1.10  Radiograph showing obturated canals

After completion of endodontic therapy, the endodontist
places the crown or other restoration so as to restore the tooth
to full function (Figs 1.11 and 1.12).

What are Risks and Complications?
It has been seen that more than 95 percent cases of endodontic
therapy are successful. However sometimes because of
unnoticed canal malformations, instrument errors a root
canal therapy may fail.

How many visits will it Take to
Complete this Treatment?

Fig. 1.8  Cleaned and shaped tooth

Nowadays most of the treatment can be completed in 1 to 2
visits. But treatment time can vary according to condition of
the tooth.


6  Textbook of Endodontics

Will I have a Dead Tooth after Root
Canal Therapy?
No, since tooth is supplied by blood vessels present in
periodontal ligament, it continues to receive the nutrition
and remains healthy.

Will the Tooth need any Special Care or
Additional Treatment after Endodontic
Treatment?
One should not chew or bite on the treated tooth until it
has been restored by the dentist. The unrestored tooth is
susceptible to fracture, so visit the dentist for full coverage
restoration as soon as possible. Do not forget to maintain good
oral hygiene by brushing, flossing, and routine check-ups.

Can all Teeth be Treated Endodontically?

Fig. 1.11  Complete restoration of tooth with crown placed
over the restored tooth

Most of the teeth can be treated endodontically. But

sometimes when root canals are not accessible, root is
severely fractured, tooth cannot be restored or tooth does not
have sufficient bone support, it becomes difficult to treat the
tooth endodontically. However, advances in endodontics are
making it possible to save the teeth that even a few years ago
would have been lost.
Newer researches, techniques and materials have helped
us to perform the endodontic therapy in better way with
more efficiency. Since introduction of rotary instruments and
other technologies reduce the treatment time, the concept
of single visit is gaining popularity nowadays. It has been
shown that success of endodontic therapy depends on the
quality of root canal treatment and not the number of visits.
In the modern world single visit endodontics is becoming
quite popular.

QUESTIONS
1. What is scope of endodontics?
2. Define endodontics and explain in detail the stages of multiple
visit root canal treatment in 12.
Fig. 1.12  Complete endodontic treatment with root canal
obturation and crown placement

Will I feel Pain during or after Treatment?
Nowadays with better techniques, and better understanding
of anesthesia most of the patients feel comfortable during the
treatment. But for first few days after therapy, one might feel
sensation especially if pain and infection were present prior
to the procedure. This pain can be relieved by medication. If
severe pain or pressure persists, consult the endodontist.

BIBLIOGRAPHY
1. Balkwill FH. On the treatment of pulpless teeth. Br. Dent J.
1883;4:588-92.
2. Harding WE. A few practical observations on the treatment of
the pulp. J Brit Dent Assoc. 1883;4:318-21.
3. Landers RR, Calhoun RL. One-appointment endodontic
therapy: a nationwide survey of endodontists. J Am Dent Assoc.
1970;80:1341.
4. Soltanoff W. Comparative study of the single visit and multiple
visit endodontic procedure. J Endod. 1978;4:278.
5. Wolch I. The one-appointment endodontic technique. J Can
Dent Assoc. 1975;41:613.


Pulp and Periradicular Tissue

  Development of Dental  
Pulp
  Histology of Dental Pulp
  Supportive Elements
  Innervation of Pulp

 
 
 
 
 

Anatomy of Dental Pulp

Pulp Chamber
Root Canal
Functions of Pulp
Age Changes in the Pulp

INTRODUCTION
The dental pulp is soft tissue of mesenchymal origin
located in center of a tooth. It consists of specialized cells,
odontoblasts arranged peripherally in direct contact with
dentin matrix. This close relationship between odontoblasts
and dentin is known as “pulp-dentin complex” (Fig. 2.1).
The pulp is connective tissue system composed of cells,
ground substance, fibers, interstitial fluid, odontoblasts,
fibroblasts and other cellular components. Pulp is actually a
microcirculatory system consists of arterioles and venules as
the largest vascular component. Due to lack of true collateral
circulation, pulp is dependent upon few arterioles entering
through the foramen. Due to presence of the specialized cells,
i.e. odontoblasts as well as other cells which can differentiate
into hard tissue secreting cells; the pulp retains its ability to
form dentin throughout the life. This enables the vital pulp to
partially compensate for loss of enamel or dentin occurring
with age. The injury to pulp may cause discomfort and the
disease. Consequently, the health of pulp is important for
successful completion of the restorative procedures. In this
chapter, we would discuss the comprehensive description of
pulp embryology, anatomy, histology, physiology and pulp
changes with age.

2

  Pulpal Calcifications/Pulp Stones/
Denticles
  Calcific Metamorphosis
  Periradicular Tissue

Dental pulp is:
•  Soft tissue of mesenchymal origin.
•  Consists specialized cells, odontoblasts. 
•   Odontoblasts  arranged  peripherally  in  direct  contact  with 
dentin matrix. 
•   Relationship  between  odontoblasts  and  dentin  is  known  as 
‘pulp-dentin complex’.
•   Surrounded  by  rigid  walls  and  so  is  unable  to  expand  in 
response to injury.
Features of pulp which distinguish it from tissue found elsewhere
in the body:
•   Pulp  is  surrounded  by  rigid  walls  and  so  is  unable  to  expand 
in  response  to  injury  as  a  part  of  the  inflammatory  process. 
Therefore,  pulpal  tissue  is  susceptible  to  change  in  pressure 
affecting the pain threshold. 
•   There  is  minimal  collateral  blood  supply  to  pulp  tissue  which 
reduces its capacity for repair following injury.
•   The  pulp  is  composed  almost  entirely  of  simple  connective 
tissue. At its periphery there is a layer of highly specialized cells, 
the  odontoblasts.  Secondary  dentin  is  gradually  deposited  as 
a  physiological  process  which  reduces  the  blood  supply  and 
therefore, the resistance to infection or trauma.
•   The  innervation  of  pulp  tissue  is  both  simple  and  complex. 
Simple  in  that  there  are  only  free  nerve  endings  and 

consequently the pulp lacks proprioception. Complex because 
of innervation of the odontoblast processes which produces a 
high level of sensitivity to thermal and chemical change.

DEVELOPMENT OF DENTAL PULP

Fig. 2.1 Pulp-dentin complex

The pulp originates from ectomesenchymal cells of dental
papilla. Dental pulp is identified when these cells mature and
dentin is formed.
Before knowing the development of pulp, we should
understand the development of the tooth. Basically the
development of tooth is divided into bud, cap and bell stage.
The bud stage (Fig. 2.2) is initial stage where epithelial
cells of dental lamina proliferate and produce a bud like
projection into adjacent ectomesenchyme.


8

Textbook of Endodontics

The cap stage (Fig. 2.3) is formed when cells of dental
lamina proliferate to form a concavity which produces cap
like appearance. It shows outer and inner enamel epithelia
and stellate reticulum. The rim of the enamel organ, i.e. where
inner and outer enamel epithelia are joined is called cervical
loop. As the cells of loop proliferate, enamel organ assumes
bell stage (Fig. 2.4).

The differentiation of epithelial and mesenchymal cells
into ameloblasts and odontoblasts occur during bell stage.
The pulp is initially called as dental papilla; it is designated as
pulp only when dentin forms around it. The differentiation of
odontoblasts from undifferentiated ectomesenchymal cells is
accomplished by interaction of cell and signaling molecules
mediated through basal lamina and extracellular matrix.
The dental papilla has high cell density and the rich vascular
supply as a result of proliferation of cells with in it.

The cells of dental papilla appear as undifferentiated
mesenchymal cells, gradually these cells differentiate into
fibroblasts. The formation of dentin by odontoblasts heralds
the conversion of dental papilla into pulp. The boundary
between inner enamel epithelium and odontoblast form the
future dentinoenamel junction. The junction of inner and
outer enamel epithelium at the basal margin of enamel organ
represent the future cementoenamel junction. As the crown
formation with enamel and dentin deposition continues,
growth and organization of pulp vasculature occurs.
At the same time as tooth develops unmyelinated sensory
nerves and autonomic nerves grow into pulpal tissue.
Myelinated fibers develop and mature at a slower rate, plexus
of Raschkow does not develop until after tooth has erupted.

HISTOLOGY OF DENTAL PULP
When pulp is examined histologically, it can be distinguished
into four distinct zones from periphery to center of the pulp
(Fig. 2.5).
Zones of pulp are:

a.  Odontoblastic layer at the pulp periphery
b.  Cell free zone of Weil
c.  Cell rich zone
d.  Pulp core

Fig. 2.2 Development of tooth showing bud stage

a. Odontoblastic layer: Odontoblasts consists of cell bodies
and cytoplasmic processes. The odontoblastic cell bodies
form the odontoblastic zone whereas the odontoblastic
processes are located within predentin matrix. Capillaries,
nerve fibers (unmyelinated) and dendritic cells may be
found around the odontoblasts in this zone.
b. Cell free zone of Weil: Central to odontoblasts is subodontoblastic layer, termed cell free zone of Weil. It contains
plexuses of capillaries and small nerve fiber ramifications.

Fig. 2.3 Development of tooth showing cap stage

Fig. 2.4 Development of tooth showing bell stage

Fig. 2.5 Zones of pulp


Pulp and Periradicular Tissue

9

c. Cell rich zone: This zone lies next to subodontoblastic
layer. It contains fibroblasts, undifferentiated cells which
maintain number of odontoblasts by proliferation and

differentiation.
d. Pulp core: It is circumscribed by cell rich zone. It contains
large vessels and nerves from which branches extend
to peripheral layers. Principal cells are fibroblasts with
collagen as ground substance.
Contents of the pulp
•  Cells 
i.  Odontoblasts 
   
ii.  Fibroblasts
   
iii.  Undifferentiated mesenchymal cells
   
iv.  Defense cells
   
–  Macrophages
   
–  Plasma cells
   
–  Mast cells
•  Matrix 
i.  Collagen fibers
   
–  Type I
   
–  Type II
   
ii.  Ground substance
   
–  Glycosaminoglycans

   
–  Glycoproteins
   
–  Water
•  Blood vessels  Arterioles, venules, capillaries 
•  Lymphatics 
D
  raining  to  submandibular,  submental  and 
deep cervical nodes
•  Nerves 
i.  Subodontoblastic plexus of Raschkow
   
 ii.   Sensory afferent from Vth nerve and superior 
cervical ganglion

Structural or Cellular Elements
Odontoblasts (Fig. 2.6)
• They are first type of cells encountered when pulp is
approached from dentin.
• Thenumberofodontoblastsrangesfrom59,000to76,000
per square millimeter in coronal dentin, with a lesser
number in root dentin.
• Inthecrownofthefullydevelopedtooth,thecellbodies
of odontoblasts are columnar and measure approximately
500µminheight,whereasinthemidportionofthepulp,
they are more cuboidal and in apical part, more flattened.
• The morphology of odontoblasts reflects their functional
activity and ranges from an active synthetic phase to a
quiescent phase.
• Ultrastructure of the odontoblast shows large nucleus

which may contain up to four nucleoli.
• Nucleusissituatedatbasalend.Golgibodiesarelocated
centrally. Mitochondria, rough endoplasmic reticulum
(RER), ribosomes are distributed throughout the cell body.
• Odontoblasts synthesize mainly Type I collagen,
proteoglycans. They also secrete sialoproteins, alkaline
phosphatase, phosphophoryn (phosphoprotein involved in
extracellular mineralization).
• Irritated odontoblast secretes collagen, amorphous
material, and large crystals into tubule lumen which result
in decreased permeability to irritating substance.

Fig. 2.6 Diagram showing odontoblasts

Odontoblasts
•  Encountered first when pulp is approached from dentin. 
•  Number ranges from 59,000 to 76,000/mm2 in coronal dentin
•  Number is lesser in root dentin.
•  Morphology reflects their functional activity. 
•  Synthesize mainly type I collagen, proteoglycans.
•   When irritated, secretes collagen and large crystals into tubule 
lumen, resulting in reduced permeability.

POINTS TO REMEMBER
Similar characteristic features of odontoblasts, osteoblasts and
cementoblasts
•   They  all  produce  matrix  composed  of  collagen  fibers  and 
proteoglycans capable of undergoing mineralization.
•   All  exhibit  highly  ordered  RER,  Golgi  complex,  mitochondria, 
secretory granules, rich in RNA with prominent nucleoli.

Difference between odontoblasts, osteoblasts and cementoblasts
•   Odontoblasts  are  columnar  in  shape  while  osteoblasts  and 
cementoblast are polygonal in shape.
•   Odontoblasts  leave  behind  cellular  processes  to  form  dentinal 
tubules  while  osteoblasts  and  cementoblast  are  trapped  in 
matrix as osteocytes and cementocytes.

Fibroblasts (Fig. 2.7)
• The cells found in greatest numbers in the pulp are
fibroblasts.
• ‘Baume’refersthemtomesenchymalcells/pulpoblastsor
pulpocytes in their progressive levels of maturation.
• These are numerous in the coronal portion of the pulp,
where they form the cell-rich zone. These are spindle
shaped cells which secrete extracellular components like
collagen and ground substance.
• Fibroblastseliminateexcesscollagenbyactionoflysosomal enzymes.


10

Textbook of Endodontics
• These cells are found throughout the cell-rich area and the
pulp core and often are related to blood vessels.
• Whenexaminedunderlightmicroscope,thesecellsappear
as large polyhedral cells possessing a large, lightly stained,
centrally placed nucleus with abundant cytoplasm and
peripheral cytoplasm extensions.
• In older pulps, the number of undifferentiated
mesenchymal cells diminishes, along with number of

other cells in the pulp core. This reduction, along with
other aging factors, reduces the regenerative potential of
the pulp.
Fig. 2.7 Histology of pulp showing fibroblasts

• Fibroblastsofpulparemuchlike‘Peter Pan’ because they
“never grow up” and remain in relatively undifferentiated
state.
Fibroblasts
•  Greatest in numbers. 
•  ‘Peter Pan’ as they “never grow up”.
•  Remain in relatively undifferentiated state.

Reserve Cells/Undifferentiated Mesenchymal Cells
• Undifferentiated mesenchymal cells are descendants
of undifferentiated cells of dental papilla which can
dedifferentiate and then redifferentiate into many cell
types.
• Depending on the stimulus, these cells may give rise to
odontoblasts and fibroblasts.

Defense Cells (Fig. 2.8)

• Histiocytes and macrophages: They originate from
undifferentiated mesenchymal cells or monocytes. They
appear as large oval or spindle shaped cells which are
involved in the elimination of dead cells, debris, bacteria
and foreign bodies, etc.
• Polymorphonuclear leukocytes: Most common form of
leukocyte is neutrophil, though it is not present in healthy

pulp. They are major cell type in microabscesses formation
and are effective at destroying and phagocytizing bacteria
and dead cells.
• Lymphocytes: In normal pulps, mainly T-lymphocytes
are found but B-lymphocytes are scarce. They appear at
the site of injury after invasion by neutrophils. They are
associated with injury and resultant immune response.
Thus their presence indicates presence of persistent
irritation.
• Mast cells: On stimulation, degranulation of mast cells
release histamine which causes vasodilatation, increased
vessel permeability and thus allowing fluids and leukocytes
to escape.

Fig. 2.8 Cells taking part in defense of pulp