Textbook of Endodontics Nisha Garg, Amit Garg
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Introduction and Scope of Endodontics1

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.
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.
1776 to 1826
Age of discovery
1826 to 1876
Dark age
1876 to 1926
The renaissance
1926 to 1976
Innovation era
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.
As we have seen, over the years, there has been a great improvement in the field of endodontics. Many researches have been conducted and papers are being presented regarding the advances, modifications and change in attitude regarding endodontic therapy.
Table 1.1   History of endodontics
Lazare Riviere
Introduced clove oil for sedative property
Pierre Fauchard
First described the pulp tissue
Pierre Fauchard
Described removal of pulp tissue
Leonard Koecker
Cauterized exposed pulp with heated instrument and protected it with lead foil
S Spooner
Suggested arsenic trioxide for pulp devitalization
Edwin Maynard
Introduced first root canal instrument
Edwin Truman
Introduced gutta-percha as a filling material
SC Barnum
Prepared a thin rubber leaf to isolate the tooth during filling
Used gutta-percha cones for filling of root canals
Use of electric current for testing pulp vitality
GA Mills
Etiologic factor of pulp sequelae was lack of vitality in the tooth
Substituted formations for arsenic to dry the nonvital pulp
Introduced gold plated copper points for filling
Otto Walkhoff
Introduced camphorated chlorophenol as a medication
Introduced formocresol
Introduction of lateral compaction technique
Use of electrical current for determination of working length
BW Hermann
Introduced calcium hydroxide
Sodium hypochlorite
Presented scientific study on apex locator
Introduced profile instrument system
Nygaard Ostby
Introduced EDTA
Ingle and Levine
Gave standardizations and guidelines for endodontic instruments
Walking bleach technique
Calculated electrical resistance between periodontium and oral mucous membrane
Introduced standardized technique
Weichman Johnson
Use of lasers
Mullaney et al.
Use of step-back technique
McSpadden technique (Thermomechanical compaction)
Marshall and Pappin
Introduction of Crown down technique
Roane, Sabala and Powell
Introduction of balanced force technique
Introduced first commercial bleaching product
Haywood and Heymann
Nightguard vital bleaching
Introduced MTA (Mineral trioxide aggregate)
Pentron clinical laboratory
Introduced Resilon
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 3with 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.
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Fig. 1.1: The scope of endodontology
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?
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, swelling, and abscess at the root end (Fig. 1.5).
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Fig. 1.2: Normal anatomy of a tooth showing enamel, dentin, cementum and pulp
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Fig. 1.3: Tooth decay causing damage to pulp
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Fig. 1.4: Radiograph showing carious exposure of pulp
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Fig. 1.5: Tooth with infected pulp and abscess formation
Sometimes, however, there are no symptoms.
Why do I need Root Canal Therapy?
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?
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).
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Fig. 1.6: Radiograph showing periapical lesion due to carious exposure
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Fig. 1.7: Cleaning and shaping of root canal system
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Fig. 1.8: Cleaned and shaped tooth
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Fig. 1.9: Obturation of root canal system
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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?
Nowadays most of the treatment can be completed in 1 to 2 visits. But treatment time can vary according to condition of the tooth.
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Fig. 1.11: Complete restoration of tooth with crown placed over the restored tooth
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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.
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?
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.
  1. What is scope of endodontics?
  2. Define endodontics and explain in detail the stages of multiple visit root canal treatment in 12.
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  1. Harding WE. A few practical observations on the treatment of the pulp. J Brit Dent Assoc. 1883;4:318–21.
  1. Landers RR, Calhoun RL. One-appointment endodontic therapy: a nationwide survey of endodontists. J Am Dent Assoc. 1970;80:1341.
  1. Soltanoff W. Comparative study of the single visit and multiple visit endodontic procedure. J Endod. 1978;4:278.
  1. Wolch I. The one-appointment endodontic technique. J Can Dent Assoc. 1975;41:613.