Pain is defined as “A more or less localized sensation of discomfort, distress or agony resulting from the stimulation of nerve endings” by Dorland’s medical dictionary. According to the Association for the study of Pain (IASP), Pain is defined as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage“. Pain is measured in Intensity ranging from mild, moderate and severe pain with the scale ranging from 0-10. 0 being no pain, 1- hurts a little, 2- hurts a little more while 10- severe pain. There are many factors which also need to be accessed causing pain Local Factors such as “Sweets, chewing, palpation, heat, cold, percussion” while conditional factors such as time of Day, posture, activities and hormonal are also considered in the initial diagnosis of the type of pain and its cause.
Pain is transmitted to the central nervous system from the head and neck region mainly through the Trigeminal System. The Subnucleus caudalis which is a part of the trigeminal spinal tract nucleus being the most inferior one located in the medulla, extending to the level of C2 and C3 and is the principal brain relay site of nociceptive information arising from the orofacial region.
Types of Odontogenic Pain and their Sources:
There are two types of pains under Odontogenic pain — Dental Pain of Pulpal Origin and Dental Pain of Periodontal Origin
Dental Pain of Pulpal Origin: Dental Pulp is a highly innervated tissue containing primary afferent fibers that are involved in pain transmission and Sympathetic efferent fibers, it is richly innervated by A-nerve fibers and C-nerve fibers. The Sympathetic efferent fibers modulate the microcirculation of the pulp by stimulating smooth muscles encircling the arterioles thus reducing the flow of blood through the pulp. Most common causes of Pulpal Pain – Reversible pulpitis, Irreversible pulpitis, Dentinal sensitivity, Necrotic pulp.
Four Types of Nerve endings present in Dental Pulp:
- Marginal fibers
- Simple predentinal fibers
- Complex predentinal fibers
- Dentinal fibers
Types of pain seen in pulp is called Threshold type where no response is seen until the threshold level is increased. Pulp stimulation can recognize both pain and touch sensation but pain.
- Stimulation of A-fibers: Fast or Acute pain which is sharp, piercing or stabbing type
- Stimulation of C- fibers: Slow Chronic Pain which is dull, burning and aching type
Pulpal responds to chemical, mechanical ad thermal stimulation but it does not respond to masticatory forces, pulpal pain comes under the Threshold type of pain where no response is seen until the threshold level is increased.
Pulpal pain can be differentiated from Periodontal pain as it does not remain the same for longer periods of time.
It is felt on stimulation and resolves and is felt again on stimulation
Pulpal pain cannot be localized by the patient
Dental Pain of Periodontal Origin: It is a type of deep omatic pain and due to the presence of proprioceptor fibers it is termed as a musculoskeletal type of pain. The differentiating factor with Pulpal pain is that, the patient can localize the pain in periodontal type which helps in readily identifying the affected tooth. Applying pressure from the lingual or buccal side can induce pain and also along the axial position.
Apart from infections, periodontal pain can be due to parafunctional habits such as bruxism or malocclusion.
Most common causes of Periodontal Pain: Acute apical periodontitis, acute apical abscess, periodontal abscess, pericoronitis, Chronic apical periodontitis.
It is a type of pain involving the Oral cavity and its surrounding structures where the source of pain is not involving the Pulp or Periodontal ligament. This type of pain can be due to any structures surrounding the Oral cavity like the Head and Neck region.
The term used for Non-Odontogenic pains resulting in toothache is Heterotrophic pain which means pain felt in the area other than is true source.
Non-odontogenic Referred pain is when the pain is due to musculoskeletal origion like muscles, joints, ligaments or deep tissue are felt as tooth pain. One such example is Tooth ache caused due to Maxillary Sinus Infection.
Odontogeic Referred pain is when adjacent teeth of an infected tooth start to pain along with the supporting structures. Pain from the Infected Second or Third molars is felt in the ear.
Myofascial or Muscular Toothache:
Any injury or damage to the Muscles of certain muscles of head and neck region can induce referred pain to the teeth. Muscles which can lead to referred pain in the teeth are masseter, temporalis, medial pterygoid, lateral pterygoid and digastric muscles. The most common muscle leading to myofascial toothache is the masseter and temporalis muscle.
Symptoms of Myofascial Pain:
- Dull and constant pain is seen
- Pain increase on function such as chewing
- Palpation of the muscle induces pain
- Anesthetizing the tooth does not reduce pain, rather anesthetizing the muscle reduces pain
How to Diagnose Myofascial Pain:
Diagnosis requires multiple diagnostic tools such as
Pulp Vitality testing of the affected tooth
Identifying the trigger points on muscles with lack of Tooth infection
Local Anesthesia Block to eliminate the affected tooth, Anesthetizing the muscle to check for pain
Treatment of Myofascial pain:
- Advise patient to not consume any hard substances
- Prevent Functional activities on the affected side
- Occlusal Rearrangement
- Maggase of the muscles affected
- Ultrasound therapy has been found useful
- Analgesics with muscle relanxants in case of severe pain
Certain Neurovascular painful conditions such Migrane, Cluster headache can lead to localized pain which match the signs and symtoms of toothache. Neurovascular toothache mimics odontogenic toothache with symptoms like deep, throbbing, spontaneous pain similar to pulpal pain. Mostly Unilateral pain. Headache is accompanied by toothache. Reduction in pain is seen with recurrence most commonly seen after a certain period of time.
Pain due to Nerves such as Trigeminal Neuralgia or Trigeminal Neuropathy can also lead to tooth pain.
Pain in the tooth or orofascial region which is caused due to underlying Cardiac problem. It is termed as Reffered pain which is seen along with other features of cardiac pain such as pain in the left arm, shoulder and neck. This type of Toothache is explained in detail here – Cardiac Toothache – Symptoms and Importance.