Physilogy of Mastication and Deglutition
Physilogy of Mastication and Deglutition
Physilogy of Mastication and Deglutition
mastication and
deglutition
By: Dr Tanmay
Srivastava
MDS 1ST YEAR
Department of
Prosthodontics
Definition
The cyclic movement produced by the elevation and
depression of the mandible as food is sheared and formed
into a bolus in preparation for swallowing.
Introduction
Mastication of food is the initial stage in the process of
digestion
55 pounds on incisors
Chewing reflex
Presence of bolus causes reflex inhibition of muscles of
mastication causing lower jaw to drop.
This inhibits jaw muscles once again allowing the jaw to drop
and rebound another time ; this is repeated again and again.
MASTICATORY MOVEMENTS
• Movements
• chewing stroke
• tooth contact
• forces of mastication
• role of soft tissue
• role of saliva
• Muscle activity
Chewing Stroke
Rhythmic
Opening movement
Closing movement
a) crushing phase
b) grinding phase
Opening phase
• During opening phase there is initial rotation of the
mandible for the first 20-27mm of interincisal distance.
• Thereafter there is translatory or bodily shift of the
mandible anteriorly and in downward direction.
Closing Phase
1) Crushing phase
2) Grinding phase
TOOTH CONTACT
Gliding contact
Centric contact
LIPS:
◦ Guide
◦ Control intake
MUSCLE ACTIVITY
◦ Species
◦ Type of food,
Lateral pterygoid
Suprahyoid muscles
Temporalis
Medial pterygoid
Lateral pterygoid
Origin
Insertion
Medial pterygoid
Origin
Insertion
Masseter
Origin
Insertion
Temporalis
Origin
Insertion
Trigeminal
Hypoglossal
Facial
Vagus
Glossopharyngeal
CONTROL OF MASTICATION
Deglutition
Consists of a reflex sequence of muscle contraction that
propels ingested materials and pooled saliva from the
mouth to the stomach. (Okeson)
Introduction
SWALLOWING MOVEMENTS
1) Preparatory phase
2) Oral phase
3) Pharyngeal phase
4) Esophageal phase
PREPARATORY PHASE
Bolus is prepared
ORAL PHASE
voluntary
PHARYNGEAL PHASE
ESOPHAGEAL PHASE
PRESSURE CHANGES
CONTROL OF SWALLOWING
Types of Swallowing
INFANTILE SWALLOW
Suckling reflex
Rooting reflex
VOMITING
Advances in diagnosis
Barium swallow
A fluroscopic, non invasive procedure where the contrast
medium is swallowed by the patient and the die is further
evaluated by radiographs.
TMJ disorders
Achlasia
Singultus (hiccups)
Parotitis
Pericoronitis
References