Botulinum toxin for OFP Flashcards
How does botulinum toxin work?
Neurotoxin produced by clostridium botulinum bacteria A to G strains. A is the most potent strain. Allergan (botox) and Dysport (Ipsen) are type A. Type B is rarely used.
Inhibits acetylcholine release by cleaving SNARE proteins and preventing release of acetylcholine into the synaptic cleft. This causes skeletal muscle paralysis. Takes between 24 hours and 72 hours to take effect and reaches peak effect at 10 days. 2 - 6 months after injection everything returns to normal because neurons form new collateral axonal sprouts (buds from the neuron) which create new neuromuscular junctions.
In pain it normalizes muscular hyperactivity, it normalizes excessive muscle spindle activity, retrograde neuronal flow to the CNS, suppresses neuropeptide secretion in nociceptors in cental and peripheral NS.
Suppression of substance P and decreases calcitonin GRP, decreased inflammation, decreased glutamate secretion, and reduces spinal dorsal horn neurone activity leading to pain relief and anti-inflammatory effects.
What are the approved orofacial indications for botulinum toxin use?
Strabismus
Cervical dystonia
Chronic migraine (more than 15 days per month of headaches)
Belpharospasm (uncoordinted muscle spasms)
Cosmetic use (forehead lines, glabellar, lines, Crow’s feet)
What are the contraindications to botulinum toxin use?
Known hypersensitivity/allergy
Pre-existing neuromuscular/neurological disease (Myaesthenia gravis, Eaton Lambert syndrome, Amyotrophic lateral sclerosis, motor neurone disease)
Infection at injection site.
Inflammation/inflammatory skin disorders at intended injection site.
Previous lower eyelid surgery
Pregnancy
Lactation
Psychological issues?
Theoretically medications that decrease neuromuscular transmission such as aminoglycosides, Ca channel blockers, penicillamine, and quinine
What are the adverse effects of using botulinum toxin?
Short term: Local = ecchymosis, pain, oedema, purpura, and transient hypoaesthesia. Post injection headaches, prolonged migraines, nausea, and malaise/flu-like symptoms. Botulism symptoms. Anaphylaxis
Medium to long term: Unwanted muscle weakness, ptosis (eyelid/lip), altered or reduced facial expression, dysphagia, neck weakness, muscle atrophy, osteopaenia of mandibular condyle.
Treatment failure often occurs due to antibody development and this occurs in 5 - 10% of patients. It is avoidable with the use of booster injections.
What are the therapeutic uses of botulinum toxin in dentistry?
Lack of clear evidence but is effective for:
Motor/neurological problems (Bruxism/pathological clenching, oromandibular dystonia)
Pain (TMD, myogenous TMD, arthrogenous TMD and neuropathic orofacial pain)
What does the dental board of Australia advise regarding use of botulinum toxin for OFP?
Dentists must perform only those dental procedures for which they have been educated, trained and are competent.
Current scope of practice includes use of botulinum toxin.
BT should only be used if treatment can be justified. It is off-label.
Administering botox would require additional training.
How does botox reduce pain?
It normalizes muscular hyperactivity
It normalizes excessive muscle spindle activity
Produces effects by retrograde neuronal flow to the CNS reducing exocytosis of pain molecules.
Suppresses neuropeptide secretion in nociceptors in central and peripheral NS.
Suppression of substance P and decreases calcitonin GRP, decreased inflammation, decreased glutamate secretion, and reduces spinal dorsal horn neurone activity leading to pain relief and anti-inflammatory effects.
How does botox reduce pain?
It normalizes muscular hyperactivity
It normalizes excessive muscle spindle activity
Produces effects by retrograde neuronal flow to the CNS reducing exocytosis of pain molecules.
Suppresses neuropeptide secretion in nociceptors in central and peripheral NS.
Suppression of substance P and decreases calcitonin Gene Related Peptide, decreased inflammation, decreased glutamate secretion, and reduces spinal dorsal horn neurone activity leading to pain relief and anti-inflammatory effects.
How does botox reduce pain?
It normalizes muscular hyperactivity
It normalizes excessive muscle spindle activity
Produces effects by retrograde neuronal flow to the CNS reducing exocytosis of pain molecules.
Suppresses neuropeptide secretion in nociceptors in central and peripheral NS.
Suppression of substance P and decreases calcitonin Gene Related Peptide,
Decreased inflammation,
Decreased glutamate secretion
Reduces spinal dorsal horn neurone activity leading to pain relief and anti-inflammatory effects.
How does botox reduce pain?
It normalizes muscular hyperactivity
It normalizes excessive muscle spindle activity
Produces effects by retrograde neuronal flow to the CNS reducing exocytosis of pain molecules.
Suppresses neuropeptide secretion in nociceptors in central and peripheral NS.
Suppression of substance P and decreases calcitonin Gene Related Peptide,
Decreased inflammation,
Decreased glutamate secretion
Reduces spinal dorsal horn neurone activity
These effects lead to pain relief and anti-inflammatory effects.
What is oromandibular dystonia?
Movement disorder characterised by involuntary spasms and muscle contractions affecting the mandible. Manifests as distorted mandibular position. It is focal in 50% of cases, segmental in 33%, and generalised in 17%.
It causes dysfunction of speech, swallowing, and eating. Can cause jaw pain.
What is the evidence of efficacy of botox for oromandibular dystonia?
No RCTs mostly case reports.
Tan et al 1999 and 2000 found that 69.7% of patients demonstrated improvement functionally.
Sinclair et al 2013 also showed improvement in >60% of patients
What are the outcomes of botox for treatment of oromandibular dystonia?
Requires botox every few months
Long term management with botox has minimal morbidity (no facial nerve paresis)
Loss of treatment effect noted in case reports.
How common is bruxism?
14 - 20% in children.
How is bruxism managed?
Self-care including improved sleep hygiene, reduction of stress, meditation, cognitive behavioral therapy.
Physical therapies
Systemic medications (eg benzos)
Oral appliances
How does botox help with bruxism?
Eliminates muscle spasms and reduces strength of contraction. Decreases the abillity to clench strongly while maintaining voluntary control
What is the evidence like in bruxism?
Limited large studies but many case reports
Further investigation is still needed.
What are the causes of myogenous TMD?
Protective co-contraction
Masticatory myalgia
Myofascial pain
Centrally mediated myalgia
Fibromyalgia
Myositis
Myofibrotic contracture
What is the aim of myogenous TMD treatment?
Management aims to decrease pain, restore normal ROM, and restore masticatory and jaw function
How is myogenous TMD typically treated?
Self-care (psychological and cognitive behavioral intervention)
Physical therapies
Systemic manifestations
Oral appliances
What does botox do for chronic myalgia or masticatory myofascial pain?
Reduces pain by reducing muscle hyperactivity.
Main goals are to reduce pain and increase functional ROM
What does the evidence show for botox use in myogenous TMD?
3 RCTs show botox to be more effective than a placebo in reducing masticatory myalgia
Nixdorf et al. 2002 showed no significant differences and in fact botox patients had decreased mouth opening compared to placebo. Sample size was small.
What are the types of arthrogenous TMD?
Congenital/developmental disorders
Disc displacement disorders (disc displacement with or without reduction and TMJ dislocation)
Inflammatory disorders (synovitis and capsulitis)
What are the management aims of arthrogenous TMD?
Aims to decrease joint loading and muscle pain/tension.
Self-care (psychological, and cognitive behavioural intervention)
Physical therapies
Systemic medications
Oral appliances
Surgical management
How effective is botox in treating arthrogenous TMD?
Botox is used in recurrent TMJ dislocation. No RCTs performed but several studeis and case series exist.
Some studies do not subcategorise TMD.
Possible effectiveness of botox in decreasing loading on the joint by decreasing muscle contraction forces
What evidence is there of botox efficacy in treating neuropathic pain?
nothing done for OFP.
Peripherally several RCTs found it to be effective for neuropathic pain. reduction in allodynia and pain thresholds
What are the typical management methods for trigeminal neuralgia?
Anticonvulsants
MVD
Rhizotomy
Gamma knife
How effective is botox for trigeminal neuralgia?
Botox used in refractory TN was effective in 100% with improved frequency and severity of pain attacks and 7 became pain free.
