9.1
Oromandibular dystonia (difficult to open mouth)
- 1.
Called lockjaw.
- 2.
Clinical feature: reduced mouth opening caused by involuntary spasm of the mastication muscles.
- 3.
Botulinum toxin injection:
- a.
Primary target muscles: temporalis (1-1) and masseter (1-2).
- b.
Secondary target muscles: medial pterygoid (1-3) only because of technical difficulties.
- a.
∗In addition, if jaw is deviated to right (left) side, then right (left) lateral pterygoid (1-4) is indicated for injection.
9.2
Oromandibular dystonia (difficult to close mouth)
- 1.
Clinical feature: difficult to close mouth caused by involuntary spasm of the mouth opening muscles.
- 2.
Botulinum toxin injection:
- a.
Primary target muscle: lateral pterygoid muscle (1-4).
- a.
9.3
Bruxism (teeth grinding)
- 1.
Clinical feature: teeth grinding (similar to oromandibular dystonia, difficult to open mouth)
- 2.
Botulinum toxin injection:
- a.
Primary target muscles: temporalis (1-1), masseter (1-2), and lateral pterygoid (1-4).
- b.
Secondary target muscle: medial pterygoid (1-3) It is recommended as secondary target muscle only because of technical difficulties. If approach to this muscle is not difficult, it could be a primary target muscle.
- a.