Lecture 15- Pain Management of the Dental Patient

Goals for dentistry patient

Identify/manage acute pain; rapidly transition to healing and return to function

Pain pathway components

Transduction → Transmission → Modulation → Projection → Perception

Transduction definition

Noxious stimulus (mechanical/chemical/thermal) converted to electrical signal at nociceptor

Transmission definition

Impulse conduction along peripheral nerves to spinal cord

Modulation definition

Spinal processing (spinothalamic tract); can amplify or dampen signal

Projection definition

Ascending pathways to thalamus

Perception definition

Conscious awareness in cortex

Pain receptor behavior

Normal: proportional response; repeated stimulation → lower threshold, terminal budding, receptive field expansion, silent nociceptor recruitment

Chronic pain mechanisms

Repeated/amplified stimulation; axonal changes; spinal cord changes; “windup”; central sensitization

Central sensitization definition

Increased excitability of CNS pain pathways → hyperalgesia + allodynia

Maladaptive pain key factors

Speed/effectiveness of initial pain treatment; nerve/CNS injury; secondary healing issues; anxiety/depression/fear

Analgesic intervention goals

Minimize magnitude/duration of nociceptive signal; modulate neuroplasticity toward adaptive healing

Pain treatment categories

Opioids; NSAIDs; local anesthetics; adjuvants/anti‑hyperalgesics; gentle handling/positioning/stress reduction

Opioids mechanism

Work centrally/peripherally; decrease acute pain signal magnitude; hyperpolarize neurons; reduce Ca²⁺ influx

Opioids role

First‑line for acute pain; ideal short‑term analgesics

NSAIDs mechanism

Anti‑inflammatory; analgesic; reduce peripheral sensitization; synergistic with opioids

NSAIDs cautions

Avoid in cold/hypotensive patients; renal/GI toxicity with poor perfusion

NSAIDs benefits

Injectable options; few contraindications short‑term; opioid‑sparing

Dental analgesia goal

Exceed expectations by blocking pain at multiple pathway levels

Indications for oral nerve blocks

Regional analgesia for oral surgery; reduce inhalant requirement; provide post‑op analgesia; limit CNS sensitization

Four major dental blocks

Rostral maxillary (infraorbital); caudal maxillary; rostral mandibular (mental); caudal mandibular (inferior alveolar)

Rostral maxillary block coverage

Maxillary 3rd premolar rostral to midline; bone, teeth, intraoral soft tissue

Caudal maxillary block coverage

Last molar rostral to midline; ipsilateral soft/hard palate mucosa + bone

Rostral mandibular block coverage

Mandibular 2nd–3rd premolar rostral to midline (variable success)

Caudal mandibular block coverage

Mandibular 3rd molar rostral to midline; bone, teeth, soft tissue

Oral block drug options

Bupivacaine or ropivacaine 0.5%; onset 5–15 min; duration 4–6 hrs; max dose 2 mg/kg (dog/cat)

Local anesthetic cautions

Do NOT combine bupivacaine with lidocaine; no need to add buprenorphine; Nocita optional

Local anesthetic max dose

2 mg/kg total for all block sites combined (dog + cat)

Block volume: cats/small dogs

0.2–0.3 mL per site (0.25 mL typical)

Block volume: medium dogs

0.3–0.6 mL per site (0.5 mL typical)

Block volume: large dogs

0.8–1.2 mL per site (1.0 mL typical)

Block volume: giant dogs

1.4–1.6 mL per site (1.5 mL typical)

Oral block equipment

1 mL + 3 mL syringes; bupivacaine 0.5%; 25g 5/8" needle (<15 kg); 22g 1/2" (>15 kg); optional Nocita

Oral block rule

ALWAYS aspirate before injecting

Rostral maxillary block technique

Palpate infraorbital foramen dorsal to distal root of maxillary PM3; advance needle rostral to opening, parallel to bone; rest inside canal

Caudal maxillary block technique

Insert needle ventral→dorsal into soft palate mucosa caudal to mandibular M2; advance 3–5 mm under nerves before bone entry

Rostral mandibular block technique

Retract labial frenulum; advance needle ventral/caudal ~15° into mental foramen; difficult in small dogs/cats

Caudal mandibular block technique

Extra‑oral approach; palpate mandibular notch; direct needle toward lingual mandibular body; rest ventral to inferior alveolar nerve entry

Adjuvant analgesics purpose

Combine with opioids to reduce dose; additive/synergistic effects; target different receptors

Ketamine mechanism

NMDA antagonist; prevents/reverses central sensitization; reduces opioid tolerance/hyperalgesia

Amantadine/memantine mechanism

NMDA antagonists; attenuate excitatory neurotransmission; treat chronic pain/windup

Gabapentin mechanism

Binds α2‑δ subunit of voltage‑gated Ca²⁺ channels; reduces CNS excitation; anti‑hyperalgesic (NOT analgesic)

Gabapentin benefits

Mild sedative; anxiolytic; reduces windup; ideal perioperative adjunct

Windup reduction

Ketamine reduces hyperalgesia; gabapentin reduces allodynia

Multimodal analgesia principle

Target multiple pain pathway levels for optimal control

Pain pathway inhibition: perception

General anesthetics; opioids; α2‑agonists

Pain pathway inhibition: modulation

Opioids; local anesthetics; α2‑agonists; benzodiazepines; phenothiazines; TCAs; NMDA antagonists; NSAIDs; anticonvulsants

Pain pathway inhibition: transmission

Local anesthetics; α2‑agonists

Pain pathway inhibition: transduction

Local anesthetics; opioids; NSAIDs; corticosteroids

Dental pain management priority

Prevent central sensitization; provide strong regional analgesia; minimize inhalant requirements

Post‑op pain strategy

Continue multimodal analgesia; maintain nerve block coverage; monitor for chronic pain development

Key concept

Effective early pain control prevents maladaptive pain and improves dental patient recovery