This document discusses various theories related to referred pain and pain perception from dental structures. It provides explanations for referred pain including dermatomal rule and convergence-projection theory. It also summarizes different theories for tooth pain perception such as dentinal nerve stimulation, dentinal receptor theory, and the popular hydrodynamic theory. Pulpal pain, periodontal pain, and other orofacial pain conditions are also briefly characterized.

1. Physiology of pain,pain control &
anxiety management

2. REFERRED PAIN
 Pain arising from deep tissues, muscles, ligaments, joint
and viscera is often perceived at a distant site from the
actual nociceptive source.
 Pain of angina pectoris  Left arm / Jaw
 Diapharamatic Pain  Shoulder / Neck
 Cutaneous pain is sharp burning and clearly localized.

3.  Referred pain frequently occurs within a single nerve root,
passing from one branch to another.
 Eg. Mandibular molar presenting with a source of pain will
commonly refer pain to a maxillary molar.
 This is fairly common occurrence with dental pain.
 Generally, if the pain is referred to another distribution of the
same nerve, it does so in a laminated manner.
 This lamination follows dermatomes.

4. THEORIES OF REFERRED PAIN:
DERMATOMAL RULE:
 Dermatome is an area of skin supplied by afferent fibers of
a single dorsal root.
 Hence if a dermatome and a visceral structure are
embryonically related, then the 2 innervations will share a
common neural segment which will enter the same dorsal
root of the spinal cord.

5. CONVERGENCE-PROJECTION THEORY:
Most popular Theory
 Primary afferent nociception from both visceral and cutaneous
neurons often converge onto the same second order pain
transmission neuron in the spinal cord.
 The brain, having more awareness of cutaneous than visceral
structures through the past experience.

7. (II) CONVERGENCE- FACILITATION THEORY:
 This theory is similar to convergence-projection, except
that the nociceptive input from the deeper structures
causes the resting activity of second order pain
transmission neuron in spinal cord to increase or be
“facilitated”.
 Visceral efferents have collaterals connecting to the
spinothalmic neurons receiving somatic pain afferents

8. SUBLIMINAL FRINGE EFFECT:
 Afferent sympathetic nerve bringing pain sensation
from a viscus terminates on a second order neuron
but at the same time it also via a collateral, stimulates
another second order neuron.
 This last mentioned second order neuron is synapsing
with a somatic neuron of the corresponding
dermatome.
 Therefore when a patient feels pain, he feels as if the
pain is coming from the corresponding dermatome.

9. THEORIES OF TOOTH PAIN
PERCEPTION
 DENTINAL NERVE STIMULATION
 DENTINAL RECEPTOR THEORY
 HYDRODYANAMIC THEORY

10. DIRECT NEURAL STIMULATION
 This theory states that stimuli in some manner as yet
unknown reach the nerve endings in the inner dentin. There
is no scientific support of this theory.
 Anderson and co-workers postulated that if dentin was
directly innervated, then chemical stimuli to the exposed
sensitive dentin surface should cause pain.
 Application of algogenic (pain-inducing) substances such as
potassium chloride, acetylcholine, 5-hydroxytryptamine, and
histamine failed to elicit a response; whereas when applied
directly to exposed pulpal tissue, an immediate response was
elicited.
 Similarly, topical anaesthetic solution when applied to the
exposed sensitive dentin did not decrease sensitivity

11.  Anderson and Naylor proposed two possible
explanations:
 1. There were no nerve elements in dentin. When pain was
evoked it was due to stimulation of receptor mechanisms
in the pulp by a disturbance transmitted through the
tubules by non-neural means.
 2. There are receptor mechanisms in dentin that could be
stimulated indirectly, but cannot be reached by direct
stimulation from chemical agents because of some barrier
to diffusion in the tubules.

13. THE TRANSDUCTION THEORY
(DENTINAL RECEPTOR
THEORY)
 Odontoblasts and their processes perceived to act as
dentinal receptors participating in initiation and
transmission of impulses
 Gunji hypothesized that free sensory nerve endings may in
some way couple with the odontoblast process to form a
mechanoreceptor complex capable of being stimulated
when the odontoblast is mechanically deformed.
 This fails to explain why dentin continues to be sensitive
following experimental destruction of the odontoblast
layer.

14.  Lundy and Stanley showed that after odontoblast
degeneration, clinical sensitivity persisted.
 Dentinal sensitivity persists following the degeneration
of both odontoblasts and intratubular nerve fibers in the
inner third of dentin.
 Such studies appear to contradict the hypothesis that
odontoblasts act as a dentinal receptor mechanism.

15. THE HYDRODYNAMIC THEORY:
 This is the most popular theory put forward by Brann
storm in 1964.
 This is based on fluid movement in the dentinal tubules.
Various stimuli such as heat, cold, air blast, (or)
mechanical pressure affect fluid movement in the dentinal
tubules.
 This fluid movement, either inward or outward, stimulates
the pain mechanism in the tubules by mechanical
displacement of the nerves closely associated with the
odontoblast and its process.
 Thus those endings may act as mechano receptors as they
are affected by mechanical displacement of the tubular
fluid.

16.  Dentin is composed of hollow tubes containing a fluid or
semifluid material.
 Neil and Kramer, however was convinced that dentinal
fluid movement was an acceptable explanation for the
generation of pain.

17. PULPAL PAIN:
 It is the most commonly experienced pain in and near the oral cavity. Pulpal pain can be diagnosed based on
clinical signs and symptoms
 Histological finding.
 Clinically pulp is referred as
 healthy,
 reversible pulpitis,
 irreversible pulpitis.
 Histological as
 Acute,
 Chronic &
 Hyperplastic.

18. HYPEREMIA:
 The increased pressure against the sensory nerve endings in the pulp might well
produce the sensation of pain.
 Application of cold produce a sharp hypersensitive response and heat produce true
transient hyperemia and a dull pain.
 An assessment of pain intensity at the time of stimulation, dental history& a thorough
dental examination allow the clinician to differentiate among the normal pulp, dentin
hypersensitivity, and the reversible inflamed pulp

19. Hyperactive pulpalgia :-
 It is characterized by a short, sharp, shock pain is felt as a sensation of sudden shock. It
is never spontaneous.
Dentin Hypersensitivity :
 Pain arise in response to thermal, chemical, tactile or osmotic stimuli and is not caused
by any other dental defect or pathology. This pain is explained by, hydrodynamic theory
postulated by Brannstrom

20. Characteristic features of irreversible pulp
condition are :
 Hyperalgesia in the initial stage
 Dull throbbing ache in the later stage
 Lingering pain on application of stimuli
 Pain is spontaneous
 Cause referred pain in other areas

21. Acute Pulpalgia :-
 Pain is nagging or boring pain which may at first be localized but finally becomes
diffuse or referred to another area in mild pulpalgia but in advanced lesion, pain is
excruciating and relieved by cold.
Chronic Pulpalgia :-
 Mild pain that is quite diffuse and is difficult to locate source of pain. It is likely to
cause referred pain which is also mild.

22. Hyperactive pulpitis :-
 Pain or slight discomfort from food coming against the tooth or on taking extreme of hot & cold.
Internal desorption :
 Pain is mild and at tolerable level and closely resemble chronic pulpalgia
Incomplete fracture or split tooth
 Pain range from those of constant unexplained hyper sensitive pulp to constant unexplained toothache. The
most frequent complaint is that of a tooth painful to bite on, with occasional mild ache.

23. PERIODONTAL PAIN:
 Localized, deep throbbing pain
 Involving inflammation of PDL around one or more teeth
 Mobility
 Localized bleeding
 Presence of pocket
 In radiograph loss of bone
 Pain last for hour or day
 Involve tooth is tender on percussion
 If pain involve multiple teeth including opposing teeth then occlusal trauma should
considered

24. Pericoronitis :-
 Severe radiating pain in posterior mouth region and inability to comfortably close or open mandible
 Tissue distal to erupting molar is most painful to touch
Ear Pain:
 Odontogenic infection of posterior teeth may refer pain to the ear/TMJ area.
 Similarly middle ear infection/otitis media/mastoiditis may be confused with odontogenic pain.
 In otitis media pain is acute, severe, throbbing and exacerbate on lowering the head.
 Pain may be referred to tooth, TMJ, tonsils, tongue, throat, trachea and thyroid.
 It is unlikely for the middle ear infection/otitis media/mastoiditis pain to be exclusively expressed as jaw
pain.

25. Sinus & Paranasal Pain:
 In acute maxillary sinusitis pain may be stabbing, with severe aching pressure.
 Pain is frequently referred upward under the orbit and downward over the maxillary
posterior teeth.
 Pain is referred in all the teeth in the quadrant and exacerbated when head is placed
below the knee.
 In chronic sinusitis there is dull constant pain.
 The location of these symptoms may vary from the maxilla and maxillary teeth in
maxillary sinusitis, to the upper orbit and frontal process in frontal sinusitis and at the
junction of the hard and soft palate, occipital and mastoid process in sphenoid sinusitis.

26. Temporomandibular Joint Articular
Disorders:
 Capsulitis and Synovitis.
 Chief complaint is continuous pain over the joint aggravated by function.
 Swelling may be evident and patient may complaint of acute malocclusion, restricted
mouth opening and teeth pain.

27. Neuralgias :
 Trigeminal Neuralgia:
 Etiology:
 Precise cause is unknown
 Evidence indicates it may be due to vascular compression of gasserian ganglion, viral infection of neuron or
nerve sheath may be there.
 It primarily involves either maxillary or the mandibular division but sometimes it may involve ophthalmic
division.
 Pain is severe and lancinating, shooting into the bone and teeth.
 Electric like quality of pain is unique and is rarely encountered in odontogenic infections. The pain episode
last only second at a time. Although paroxysms may occur in rapid succession.
 A trigger zone exists somewhere on the facial skin or occasionally in the oral cavity.

28. Treatment:
 It is essential to establish diagnosis and avoid any invasive procedure.
 Carbamazipine (Tegretol)
 Peripheral neurectomy
 Rhizotomy
 Alcohol injection
 Cryotherapy
 Radiofrequency lesioning
 Laser therapy
 Surgical decompression
 Trans cutaneous ganglionic neurolysis

29. Post herpetic Neuralgia:
 This disease represent a recrudescence of a latent virus located in sensory ganglion.
 The painful lesions of shingles cause a deep, boring ache involving not only the
superficial mucosal and cutaneous tissues but also the maxillary and mandibular bones.
 Occurrence of prodromal pain obscure the diagnosis.
 Prodromal pain is acute and electric like and the pain associated with vesicular
eruption is deep and boring.
 Once the vesicles clear, the residual pain is of burning quality and chronic. The quality
of pain may be confused with odontogenic pain but the history of vesicular eruption is
sufficient to make a diagnosis

30. Treatment of post herpetic neuralgia:
 TENS
 Anti seizure drugs
 Analgesics

31. Glosso Pharyngeal Neuralgia :
 It include unilateral rarely bilateral stabbing pain in the lateral posterior pharyngeal and
tonsilar area, the base of the tongue, down in to the throat, the Eustachian tube or ear
and down the neck.
 Sometimes the pain radiates into vagus region and may be associated with salivation,
flushing, sweating, tinnitus, cardiac arrhythmias, hypertension, vertigo or syncope.

32. Eagle’s Syndrome :
 It is similar to those of gloss pharyngeal neuralgia but involve compression of the area
of IXth nerve by a calcified elongation of styloid process of the temporal bone.
 Precipitating factors include fast rotation of head, swallowing, pharyngeal motion from
talking and chewing.

33. MYOFACIAL PAIN:
 The most common form of musculoskeletal pain affecting the head, neck and face.
 The main characteristic features are –
 Myofacial trigger point
 Muscle affected have a reduced active range of movement
 Referred pain in reproducible patterns remote from the site of the rigger point
 A jump sing and verbal response or reflex reaction occur on palpation of the trigger
point Pain is deep, dull aching and provocable.

34. ATYPICAL ODONTALGIA:
 The most likely mechanism involved in atypical odontalgia (AO) is related to deafferentation following
injury to a nerve.
 Deafferentation refer to the partial or total loss of an afferent nerve supply from a particular area, following
trauma during dental procedure.
 Nerve damage is reversible in most patient but in some patient (3%). It is permanent.
 Pain may not appear for week, month or even a year after the procedure.
 It has been hypothesized that there is genetic predisposition towards pain in these patients. Involvement of
sympathetic nervous system (SMP) in AO has been suggested.

35.  Characteristics of pain in atypical odontalgia are:
 Chronic aching pain
 Pt feel it as deep within the bone & it is hard to localize.
 In many Pt symptoms appears to wonder from site to site.

36. PAIN IN INFANTS
The postnatal period is a time of considerable synaptic growth
and reorganization in the dorsal horn of the spinal cord and
that the developing nociceptive system responds differently to
injury (i.e., increased excitability and sensitization) when
compared to the mature adult system .
(Fitzgerald 2000; Fitzgerald and Howard 2003)
Some inhibitory mechanisms in the dorsal horn are immature at
birth and descending inhibition is delayed
(Boucher et al. 1998; Jennings and Fitzgerald 1998).

37. Repeated mechanical stimulation at strong (but not pain-
inducing) intensities can cause sensitization in very
young infants (Fitzgerald et al. 1988) and that
preliminary studies have noted a striking
hypersensitivity (to touch as well as pain) in infants
after surgery (Andrews and Fitzgerald 2002).
Pain experienced by neonates has both immediate and
longer-term effects on their pain reactivity (Grunau et
al. 2001a,b; Johnston et al. 2003).

38. Children’s pain perception:
Children can experience many different types of acute,
recurrent, and chronic pain and that the lifetime prevalence
for most types of recurrent and chronic pain increases with
age (McGrath 1999).
Children’s age and developmental level influence their
perception of pain and that children’s understanding of pain,
pain coping strategies, and the impact of pain increase with
age
(Ross and Ross 1984; Gaffney and Dunne 1987; Harbeck and
Peterson 1992; Gaffney 1993).
Most studies of children’s acute pain caused by invasive
medical procedures reveal that pain intensity and overt
distress generally decrease with age
(Jay et al. 1983; Fradet et al. 1990;)

39. AGE AND THE PERCEPTION OF
PAIN
 Pre-term infants
Have anatomical and functional ability to
process pain by mid to late gestation; seem to
have greater sensitivity to pain than term infants
or children
 Newborn infants
Response to pain is inborn and does not require
prior learning; respond to pain with behavioral
cues: facial, crying, body movement

40.  Infants 1 month
Infants can metabolize analgesics and anesthesia
effectively; can increasingly recognize caregiver as
comforter
 Toddlers / Preschoolers
Can describe pain, its location and intensity; respond
to pain by crying, anger, and sadness; may consider
pain a punishment; may hold someone accountable for
pain and remember experiences in a certain location
such as a clinic

41.  School-age children
May try to be brave when facing a painful procedure;
may regress to earlier stage of development; seek to
understand reasons for pain
 Adolescents
May be slow to acknowledge pain; may consider showing
signs of pain a weakness; with persistent pain may regress
to earlier stages of development

42.  Adults
Fear of pain may prevent some adults from seeking care;
may believe admission of pain is a weakness and
inappropriate for age or sex; may consider pain a
punishment for moral failure
 Older adults
May have decreased sensations or perceptions of pain; may
consider pain an inevitable part of aging; chronic pain may
produce anorexia, lethargy, and depression; may not report
pain due to fear of expense, possible treatment, and
dependency; often describe pain in nonmedical terms such
as "hurt" or "ache"; may fear addiction to analgesics.

43.  Children And Pain
 Children are definitely different from adults with regards to
pain perception and reaction
 Children do not have the same amount of COGNITION,
SELF CONTROL and COPING SKILLS.
 Therefore all children should be handled with extreme
care, love and affection.

45. Assessing Pain
 The single most reliable indicator of the existence and intensity
of pain is the patients self-report of pain
 . The patients' report of pain should be the primary source of
information, since it is more accurate than the observations or
others.

46.  Assessment Of Pain
 Self-reported measures of pain — These measures include
routine questions, visual analog scale, verbal scales, numeric
scales, and pictorial scales.
 Physiologic measures of pain — These include blood pressure
and pulse changes, in addition to measurement of palm-
sweating.
 Behavioral measures of pain — Such measure include motor
responses, facial expressions, crying, and behavioral responses
(i.e., sleep-wake patterns).

47. Question The Patient
 Obtain a detailed assessment of pain
 HPI, description of pain, experience with pain medications, use
of non-pharmacologic techniques, family experience with pain
 Quality, location, duration, intensity, radiation, relieving &
exacerbating factors, & associated symptoms
 Use appropriate pain scale
 Cognitively impaired adults, Sedated patients Children
 Pain can be multi-dimensional and therefore, tools can be limited
 Directly ask patients and or family when appropriate

48. SOCRATES
 Site - Where is the pain?
 Onset - When did the pain start,
was it sudden or gradual?
 Character - What is the pain like?
 Radiation - Does the pain radiate anywhere?
 Associations - Any other signs or symptoms
associated with the pain?
 Time course - Does the pain follow any pattern?
 Exacerbating/Relieving factors - Does anything
change the pain?
 Severity - How bad is the pain?

49. Question the Patient
 May not be straight forward especially in
Cognitively impaired adults
The learning disabled
Sedated patients in an ICU or operating room
setting
Children

50. Use Pain Rating Scales
 Select a scale that is suitable for the patients abilities, age, and preferences
 Teach patient to use scale before pain is expected, such as preoperatively
 Use same scale with the patient each time pain is assessed

51. Types of Pain Rating Scales
 Single Dimensional Scales
 Visual Analog Scale (VAS)
 Numerical Rating Scale (NRS)
 Verbal Descriptor Scale(s) (VDS)

52. Types of Pain Rating Scales
 Multidimensional Scales
 McGill Pain Questionnaire
 Short-Form McGill Pain Questionnaire
 Brief Pain Inventory
 Scales for Neuropathic Pain

53. Visual Analog Scale

54. Verbal Descriptive Scale

55. Numerical Rating Pain Scale

56. 0 2 4 6 8 10
Wong Baker Faces Pain Scale

60. Short-Form McGill Pain Questionnaire

61. Special Populations
 Common populations that are challenging to assess pain
 Children
 Cognitively impaired adults
 Adults whose cognition is temporarily impaired, by
medication or illness
 The learning disabled
 Sedated patients in an ICU or operating room setting

62.  Facial expressions (grimacing)
 Less obvious: slight frown, rapid blinking, sad/frightened, any
distortion
 Vocalizations (crying, moaning, groaning)
 Less obvious: grunting, chanting, calling out, noisy breathing, asking
for help
 Body movements (guarding)
 Less obvious: rigid, tense posture, fidgeting, pacing, rocking, limping,
resistance to moving
Nonverbal Pain Indicators

63. Physiological Indications of
Acute Pain
 Dilated pupils
 Increased perspiration
 Increased rate/ force of heart rate
 Increased rate/depth of respirations
 Increased blood pressure
 Decreased urine output
 Decreased peristalsis of GI tract
 Increased basal metabolic rate

64. Possible Physiologic Signs of Pain
  Pallor or flushing
 Diaphoresis, palmar sweating
  O2 saturation
  Vagal tone
 EEG changes

65. Dolorimetery
 Dolorimetry has been defined as "the measurement of pain
sensitivity or pain intensity.“
 A dolorimeter is an instrument used to measure pain threshold and
pain tolerance.
 Introduced in 1940 by James D. Hardy of Cornell University
 There are several kinds of dolorimeters that have been developed.
 Dolorimeters apply steady pressure, heat, or electrical stimulation
to some area, or move a joint or other body part and determine
what level of heat or pressure or electric current or amount of
movement produces a sensation of pain.

66. Dolorimeters

67. Pediatric Pain
 Barriers are often present and include:
 Belief that children, especially infants, do not feel pain the way adults do
 Lack of routine pain assessment
 Lack of knowledge in pain treatment
 Belief that preventing pain in children takes too much time and effort

68. Facial Expression of Physical Distress
NASO-
LABIAL FOLD
deepened

69. Pediatric Pain Scales
 Neonates, infants, toddlers (<3 years)
 Pain assessment it largely observational
 Cannot distinguish between pain, fear, anxiety, distress
 Examples of pain scales in this population:
 CRIES, PIPP, FLACC, Comfort

70. Pediatric Pain Scales
 Toddlers to school age children (3-8)
 Self Report Scales
 Visual Analog (VAS): Age 5+
 Faces/Oucher Scale/ Wong- Baker: Age 3+
 Observational Scales
 FLACC: Age 2 mos- 7 years
 CHEOPS scale age 1-7 years

71.  The COMFORT Scale is a behavioral, unobtrusive pain scale
that may be used by a healthcare provider when a person
cannot describe or rate their pain.
 Unconscious and ventilated infants, children and adolescents.
 This scale has eight indicators (categories)
 Validated for newborn to 3 years old
 Reported use of up to 17 years old
 The COMFORT Scale provides a pain rating between 9 and
45
 17-26 generally indicates adequate sedation and pain control.
COMFORT Observer Pain Scale

73. CRIES Pain Scale
 The CRIES Pain Scale is often used in the neonatal healthcare setting.
 CRIES is an observer-rated pain assessment tool which is performed by a healthcare
practitioner such as a nurse or physician.
 CRIES assesses crying, oxygenation, vital signs, facial expression and sleeplessness.
 The CRIES Pain Scale is generally used for neonates, from 32 weeks gestation to 6
months old.

74. CRIES Observer Pain Scale

75. FLACC Pain Scale
 FLACC stands for face, legs, activity, crying and consolability.
 It is an observer rated pain scale, performed by a healthcare
practitioner such as a doctor or a nurse.
 The FLACC pain scale was designed for neonates at 2 months,
may be useful up to 7 years of age.
 However, some practitioners in adult settings may use the FLACC pain
scale for people who are unable to communicate their pain.
 FLACC provides a pain assessment scale between 0 and 10.

76. FLACC scale

77. Children's Hospital of Eastern Ontario
Pain Scale (CHEOPS)
 The CHEOPS (Children's Hospital of Eastern Ontario Pain Scale) is a
behavioral scale for evaluating postoperative pain in young children.
 Six items: Cry, Facial, Child Verbal, Torso, Touch, and Legs
 It can be used to monitor the effectiveness of interventions for reducing the
pain and discomfort.
 Patients:
 The initial study was done on children 1 to 5 years of age.
 According to Furnish (2013) it is intended for ages 1-7.
 It has been used in studies with adolescents but this may not be an
appropriate instrument for that age group.

79. Oucher Scale
 Available in three ethnic versions
 Suitable for a 3-7 years of age
 Empowers the child to express pain experience
 May reflect mood instead of pain

80. White child, 3 year-old male Black child, 3 year-old male Hispanic child, 3 year-old male
Oucher Photographic / Numeric Pain Scale

81. Premature Infant Pain Profile (PIPP)
 Developed at the Universities of Toronto and McGill in Canada.
 Used for infants less than 36 weeks gestation
 Scores <6= minimum Pain, 6-12 = mild-moderate Pain, >12 =
moderate to severe pain
 Scoring instructions:
 Score gestational age before examining infant.
 Score the behavioral state before the potentially painful event by observing the
infant for 15 seconds .
 Record the baseline heart rate and oxygen saturation.
 Observe the infant for 30 seconds immediately following the painful event.
 Score physiologic and facial changes seen during this time and record immediately.

83. Neonatal Infant Pain Scale (NIPS)
 The Neonatal Infant Pain Scale (NIPS) is a behavioral scale and
can be utilized with both full-term and pre-term infants.
 From birth to one year of age
 The tool was adapted from the CHEOPS scale and uses the
behaviors that nurses have described as being indicative of infant
pain or distress.

84. Neonatal Infant Pain Scale (NIPS)

85. Children between 3-8 years
Usually have a word for pain
Can articulate more detail about the presence and location
of pain; less able to comment on quality or intensity
Examples:
Color scales
Faces scales

86. Children older than 8 years
Use the standard visual analog scale
Same used in adults

87. painDETECT
 A new screening questionnaire to
identify neuropathic components in
patients with back pain.

88. 1. Communication
2. Behavior shaping
•Desensitization
•Modeling
•Contingency management
3. Behavior Management
• Audio analgesia
• Voice control
• Coping
• Retraining
• Humor
• Implosion therapy
• Aversive conditioning
Behavior Management
PharmacologicalNon Pharmacological
1. Premedication
• Sedatives and Hypnotics
• Antianxiety Drugs
• Antihistamines
2. Conscious Sedation
3. General Anasthesia

89. CONCLUSION
 A clinician is always challenged with patient
vague description of his painful condition.
Hence adequate knowledge of pain will have
his analytic skill and leading to better
understanding of patient conditions and
effective treatment delivery.