DENTAL PAIN WABeresford Dental pain enters consciousness (HURTS)

DENTAL PAIN WABeresford Dental pain enters consciousness (HURTS)

DENTAL PAIN WABeresford Dental pain enters consciousness (HURTS) & becomes a major aspect of dentistry What is the innervation of the tooth & periodontium? How are these nerve fibers and endings related to dental pain? How do the stimuli - heat, inflammatory mediators, etc - activate the nerve fibers? What are the central pathways, structures, & interactions bringing pain to conciousness? DENTAL SENSITIVITIES SENSITIVE?

Enamel Dentine Pulp Cementum PDL PULP INNERVATION 1 Nerves: autonomic Sub-odontoblastic plexus in cell-poor zone of Weil 2

3 Nerves: sensory (V) to 1 PULP 2 ODONTOBLASTS 3 DENTINAL TUBULES Blood vessels EXTENT of TOOTH INNERVATION Sub-odontoblastic plexus of Raschkow Most fibers branch Hundreds of nerve fibers per tooth

Fibers grow in during development & some transfer to 2 0 tooth, so 20s have more nerves fibers than 10s FIBER CALIBER & MODALITY 80 % unmyelinated C fibers Hundreds of nerve fibers per tooth 10 % myelinated Ad fibers < 1/2% Ab fibers No specialized receptors

NOCICEPTION - pain - sensory modality for pulp & dentine FIBER FUNCTIONS NOCICEPTION - pain - the sensory modality for pulp & dentine Hundreds of nerve fibers per tooth But what do these do? < 1/2% Ab fibers Any trophic effects on pulp

from sensory fibers? Autonomic roles PNS: AUTONOMICS Sympathetic fibers Pulp vessel Other targets? V Sup Cervical Ganglion Branch of external carotid A

PNS:CNS Sensory relations Superior alveolar nerves Spinal nucleus of V CNS Inferior alveolar nerves Trigeminal ganglion Convergence from several teeth onto one CNS neuron PAIN QUALITY ACUTE, SHARP DULL ACHE myelinated Ad fibers

unmyelinated C fibers POOR LOCALIZATION Convergence Spinal nucleus of V CNS Inferior alveolar nerves Trigeminal ganglion PERIODONTAL LIGAMENT INNERVATION Sup Cervical Ganglion Sympathetic

Free ending Ruffini receptors V Ganglion CNS Mesencephalic nucleus of V Mechanoreceptors for stretch Modalities: PROPRIOCEPTION & pain CNS: Dental pain pathways SENSORY CORTEX

Parietal lobe Thalamic VPM Reticular formation Periaqueductal grey (PAG) Spinal N V Spinal V tract Mesencephalic N of V Sensory V Nucleus TRIGEMINAL NERVE CNS

CNS: Dental pain pathways SENSORY CORTEX Thalamic VPM Reticular formation Spinal N V Spinal V tract Mesencephalic N Sensory V Nucleus TRIGEMINAL NERVE Periaqueductal grey

(PAG) can inhibit ascending pain signals by using endorphins, enkephalins RETICULAR FORMATION: Roles Reticular formation sends signals everywhere Cortex - arousal Hypothalamus autonomic responses Limbic system emotions Motor nuclei - reflexes Sensory relays - Inhibition of incoming & ascending sensory signals NERVE-FIBER:STIMULI RELATIONS I Direct pulp

stimuli ODONTOBLASTS Worn dentine brings stimuli nearer to pulp Pulp Enamel 2 3 Heat Cold Pressure Chemicals? Axons in tubules Axons around

odondoblast bodies Sub-odontoblastic plexus ODONTOBLAST as sensory transducer ? NERVE-FIBER:STIMULI RELATIONS II ODONTOBLASTS Worn dentine brings stimuli nearer to pulp Pulp Enamel 2 3

Axons in tubules Axons around odondoblast bodies Pulp fibers sensitized by factors released because of inflammation or previous activity Heat Cold Pressure Chemicals NERVE-FIBER:STIMULI RELATIONS III ODONTOBLASTS Dentine Enamel Axons in tubules

Axons around odondoblast bodies HYDRODYNAMIC hypothesis of sensitivity Heat Cold Pressure Stimuli move fluid back & forth in the tubule stimulating tubule axons &/or odontoblasts NERVE-FIBER:STIMULI RELATIONS IV

ODONTOBLASTS Dentine Enamel Axons around odondoblast bodies Heat Cold Pressure Stimuli move fluid back & forth in the tubule HYDRODYNAMIC hypothesis of sensitivity

with distortion of the odontoblast possibly causing it to release ATP, and thus chemically exciting the axon - Alavi AM et al. Immunohistochemical evidence for ATP receptors in human pulp. J Dent Res 2001;80:476-483 HYDRODYNAMIC hypothesis of sensitivity ODONTOBLAST as sensory transducer ? Stimuli move fluid back & forth in the tubule with distortion of the odontoblast possibly causing it to release ATP, and thus chemically exciting the axon - Alavi AM et al. Immunohistochemical evidence for ATP receptors in human pulp. J

Dent Res 2001;80:476-483 DENTAL PAIN: Unknowns Stimulation mechanisms in pulp - normal & diseased Reticular formation - what happens centrally Patterns of firing - relation to perceptions PAIN: Difficult to study First Anatomy Journal about 1860; first Pain journal 1973 Animal cannot tell of pain; humans reluctant to let you hurt them or do invasive investigations, e.g., nerve recordings Allowed to work on animals only if pain is prevented or minimised Many small nerve fibers used for other purposes, e.g., autonomic

No specialized pain endings? Defining pain stimuli? Complex chemistry with tissue injury Poorly understood dynamic interactions between CNS & PNS - Pain is in the mind & usually in the body (CNSPNS interactions: compare sexual arousal)

Recently Viewed Presentations

  • COMMUNIO of ExcellenceSchools Among our Catholic DRAFT (4/15/12)

    COMMUNIO of ExcellenceSchools Among our Catholic DRAFT (4/15/12)

    FULL CYCLE: BY FOCUS. ... Offer members of the Diocesan Pastoral Council and the Diocesan Finance Council as well as curial staff to visit with the local School Commission to review policy making procedures and support them in training for...
  • The Adolescent Reading Singer by Don L. Collins

    The Adolescent Reading Singer by Don L. Collins

    It is not to be transposed one octave lower as is the custom for adult males when they sing music written in the treble clef. Boys in the first phase of vocal change can more easily relate to the treble...
  • Barajlar ve Baraj Hazneleri

    Barajlar ve Baraj Hazneleri

    General guidelines for a reservoir location: Cost of the dam Cost of real estate Topographic conditions to store water Possibility of deep reservoir Avoiding from tributary areas Quality of stored water Reliable hill-slopes Reservoir Yield Yield: Amount of water that...
  • Civilization Studies Program (AUB) CVSP 202: The Monotheistic ...

    Civilization Studies Program (AUB) CVSP 202: The Monotheistic ...

    "Your Majesty," said the human, "we have both traditional religious arguments and rational proofs of our position." "Very well," said the King, "lets us hear them." (Ikhwān,Epistle 22: The Case of the Animals vs. Man before the King of the...
  • Animal Behavior - Winston-Salem/Forsyth County Schools

    Animal Behavior - Winston-Salem/Forsyth County Schools

    Habituation. Habituation - response is slowed or stopped due to being exposed to the stimulus a number of times. Simplest form of learning. Ex: Ragworms will retreat to their burrows when a shadow passes over them. They will eventually stop...
  • Cornell Notes: Unit 1

    Cornell Notes: Unit 1

    Europe, Asia & Africa in one hemisphere and the Americas in the other. B. Voyages = exchange of people, plants, animals, & germs = The Columbia Exchange. Impacted world's cultures. POSITIVE EX: the horse for the Native Americans in the...
  • Sport, Exercise and Health Science - Weebly

    Sport, Exercise and Health Science - Weebly

    Usually a complex combination of emotional and physiological factors. Emotional- demands of competition, desire to win, fear of failure, unattainable goals. Emotional Factors can lead to the decrease in enthusiasm. Some studies (Armstrong & VanHeest) discuss large number of similarities...
  • A Raisin in the Sun

    A Raisin in the Sun

    Sassy aghast silly Content "Eat Your eggs" ... Choose a representative from your group to come to the front of the class with your sentence strip. Representatives will arrange themselves in what they think is the order of the poem....