THE PHYSIOLOGY OF DENTAL PAIN

E-Facilitator: Cathy


CONTENT OF THIS WIKI PAGE
NUMBER
CONTENTS
1
Pathways Involved with the Perception of Dental Pain
2
Types and Location of Receptors found in the Tooth
3
Types and Location of Receptors found in Supporting Dental Tissues
4
Managing and/or Minimising Dental Pain
5
References


1. PATHWAYS INVOLVED WITH THE PERCEPTION OF DENTAL PAIN


Dental pain is perceived through the stimulation of the mandibular and the maxillary branches of the trigeminal nerve (See figure 1.1) (the 5th cranial nerve). The afferent fibres of the trigeminal system travel via the gasserian ganglion, where their cell bodies are located, to enter the pons at the lateral aspect. Fibres concerned with discriminative tactile sensation, touch and pressure, synapse in the main sensory nucleus of the trigeminal nerve. Pain and temperature fibres, however, follow the descending spinal tract of the trigeminal nerve.

FIGURE 1.1- The trigeminal nerve

trigeminal-image.jpg



2. TYPES AND LOCATION OF RECEPTORS FOUND IN THE TOOTH


The tooth is composed of enamel, dentine and pulp which all withhold a certain function. Due to embryological backgrounds, close proximity and independence the dentine and pulp form whats called the "dentine-pulp complex". Within the dentine there are tubes which contain dentinal fluid and odontoblastic processes. Stimulation of exposed dentinal tubules, (EG; bruxism, attrition, abrasion, erosion, chips or fractures) can cause a change in dentinal fluid, which is then transmitted to the nerve cell bodies in the odontoblastic layer in the outer pulpal wall. This signal is then transmitted to the brain through the direction of nerves and is read as sensitivity/pain. The change in dentinal fluid can be caused by a number of factors but the most common are heat, cold and sweet foods or drinks.

FIGURE 1.2- Cross-sectioned tooth displaying the close proximity of the dentine/pulp compex

Tooth (section of a molar)
Tooth (section of a molar)




3. TYPE AND LOCATION OF RECEPTORS FOUND IN THE SUPPORTING DENTAL TISSUES


The tissue which supports the tooth is called the periodontium. This peridontium is composed of cementum, alveolar bone and periodontal ligament and each of these tissues perform a specific task. We can see from figure 1.2 where each of these tissues are located. Cementum attaches teeth to the alveolar bone by way of the periodontal ligament. It has no impact on dental pain as it has no innervation and is avascular. Cementum receives its nutrients from the surrounding periodontal ligament. The alveolar bone acts to support and protect the teeth and can be easily remodelled. The periodontal ligament provides attachment of the teeth to the surrounding alveolar bone. The periodontal ligament also has a vascular supply, lymphatic supply and nerve supply which enter the tooth via the apical foramen to supply the pulp of the tooth. A sensory and sympathetic nerve is also found in the periodontal ligament. The sensory nerve transmit sensations and the sympathetic regulates blood vessels.
In the outer pulpal wall there is a layer of nerve cell bodies called the odontoblastic layer. The processes that pick up the change in dentinal fluid are the processes of these nerve cell bodies which extend into the dentinal tubules.

4. MANAGING ON MINIMISING DENTAL PAIN


Dental pain can be managed in a number of different ways depending on the causative factor. As an operator it is vital to ensure patient comfort and be aware of patient status.Signs and symptoms of dental pain are not always obvious to an operator, therefore it is important to look for actions such as clenching fists, sweating, gripping the chair and various other physical actions which signifies associated dental pain. Then once the pain stimulus is identified the operator may be able to help eliminate the pain the patient is facing.

Some effective chemical measures of anxiety and pain relief include; nitrous oxide, green whistle, local anesthesia, general anesthesia and topical anesthesia. These are all treatments which are easy to use and are applicable to minimising dental pain on a short term basis.

When an operator is approached by a patient with a toothache, the operator will ask a series of questions relating to when the pain occurs, where it hurts and what stimulates the pain. Generally sharp pain is a result of hot and cold drinks/foods as there is cavitation or exposure in the tooth which stimulates the nerve to cause a painful response. This pain can range from chronic to mild, sharp and excruciating. There are various treatment methods available and can vary from a filling, restoration or even a fissure sealant. In some cases either the pain experienced or placing of the restoration can act as a motivational tool to change the tooth brushing technique and/or change to less abrasive toothpastes to suit sensitive teeth.
The use of a fluoride application can also be applied professionally as a varnish or gel or simply as a mouthwash at home. This places fluoride deep into the enamel crystals to allow for stronger and healthier teeth.
When any pain occurs, it is common to provide pain killers. There is no exception with dental pain to help relieve the pain temporarily. However, as the dental pain is only relieved temporarily, it is not the best treatment method since the original cause of the pain still needs to be treated.

It is important as an operator to provide a great amount of concentration to prevent undesirable outcomes such as surgical treatment methods including root canal treatment or the removal of a certain tooth. When dental pain occurs, the best method to overcome it is to diagnose the reasons in order to identify what caused the pain originally. Diagnosis procedures may include examining for cavities, the surrounding tissue structures of the gingiva and cheeks, the use of x-rays to diagnose any internal abnormalities in tooth and tissue structure. As well as the use of a temperature test where a hot or cold material is applied to the tooth to assess its sensitivity or biting onto a gauze to consider tooth cracks.


5. REFERENCES

Bath-Balogh M & Fehrenbach MJ 2006, Dental Embyology, Histology, and Anatomy, Elsevier Saunders, St. Louis, Missouri
Fehrenbach MJ, Herring SW & Thomas P 2007, Anatomy of the Head and Neck, 3rd Edn, Saunders Elsevier, St. Louis, Missouri
Harris, NO and Garcia-Codoy, F 2004, Primary Preventive Dentistry, 6th edn, Pearson Education, Sydney, Australia
Kidd EA.M 2005, Essentials of Dental Caries, Oxford University Press, Oxford, New York
Marieb EN & Hoehn K 2007, Human Anatomy and Physiology, 7th Edn, Pearson Benjamin Cummings, San Francisco, CA
Mount, J and Hume,WR 2005, Preservation and Restoration of tooth structure, 2nd edn. Brighton, QLD
Wilkins EM 2005, Clinical Practice of the Dental Hygienist, 9th Edn, Lipponcott Williams and Wilkins, Baltimore MD
Wolf HF & Hassel TM 2006, Color Atlas of Dental Hygiene, Periodontology, Thieme, Stuttgart, New York
FIGURES-
Trigeminal Nerve (Figure 1.1)- www.nucleusine.com
Tooth Anatomy (Figure 1.2)- www.infovisual.info