Devlopment of tongue/ oral surgery courses

DEVELOPMENT OFDEVELOPMENT OF
TONGUETONGUE
INDIAN DENTAL ACADEMYINDIAN DENTAL ACADEMY
Leader in continuing Dental EducationLeader in continuing Dental Education
www.indiandentalacademy.com

Contents
• Introduction
• Development of Tongue
• Tongue muscles
• Blood supply
• Nerve supply
• Taste sensation
• Clinical examination
• Applied aspect
• Conclusion
• Bibliography

Introduction
• Tongue is a complex muscular organ that is
anchored to hyoid bone, styloid process,
and genial tubercles of the mandible at the
insertion of 3 extrinsic tongue muscles.

• Tongue is divided into
– Anterior part/Oral portion
– Posterior part/Base of the tongue
– Superior part/Dorsum of the tongue
– Under surface/Ventral surfaces

Functions of the tongue
• Ingestion
• Suckling
• Swallowing
• Perception of taste
• Phonation
• Respiration
• Jaw development

Development of tongue
• The development of tongue starts in the fourth
month of intra uterine life .
• The tongue develops in relation to the pharengeal
arches in relation to the developing mouth.
• The phareangeal arches are mesodermal
thickenings in the lateral wall of the foregut .They
grow ventrally to become continuous with the
corresponding arch of the opposite side.

• The medial most parts of mandibular arches
proliferate into two lingual swellings .
• The lingual swellings are separated from
each other by another swelling in the
midline – tuberculum impar.
• Behind the tuberculum impar , the
epithelium proliferate to form a down
growth. This site is marked by a depression
called foramen caecum.

• Hypobrancial eminence is a midline
swelling seen in relation to medial part of
second third and fourth brancial arches. It
is sub divided into
• cranial part (II and III arches) called
copula.
• Caudal part (IV arch)

• Anterior 2/3 rd of the tongue is formed by
fusion of two lingual swellings and
tuberculum impar.
• Posterior 1/3 rd of tongue is formed by
cranial part of hypobranchial eminence.
• The posterior most part of the tongue is
formed by the IV arch.

• Development of tongue musculature
• The intrinsic tongue musculature develops
from occipital mytomes .
• Development of tongue epithelium-is at first
made of single layer of cells . It later
becomes stratified and papilla becomes
evident .
• Taste buds are formed in relation to terminal
branches of innervating nerve fibers.

They start and wholly end
with in the tongue.
They include:
 Superior longitudinal
 Inferior Longitudinal
 Transverse group
 Vertical group
Intrinsic Group:
Tongue Musculature

Extrinsic Group :
Are the group of
muscles that
originate outside
and run into it :
They include:
Hyoglossus
Styloglossus
Palatoglossus
Genioglossuswww.indiandentalacademy.com

Papillae
• Tongue is covered with stratified squamous
epithelium. Scattered throughout this
epithelium, on the uppermost surface are 4
types of elevated structures known as
papillae.

Types of Papillae
• Fungiform
• Filiform
• Foliate
• Circumvallate

Fungiform papillae
• Present in the anterior
part of the tongue.
• Scattered among the
numerous filiform
papillae at the tip of
the tongue.
• Taste buds are present
in the epithelium on
the superior surface.

Filiform papillae
• Cover the entire
anterior part of the
tongue by keratinzed
epithelium.
• They form a tough
abrasive surface
involved in
compressing and
breaking food when
the tongue is opposed
to the hard palate.www.indiandentalacademy.com

Foliate papillae
• Present on the lateral
margins of the
posterior part of the
tongue.
• Few taste buds are
present in the
epithelium of the
lateral walls of the
ridges.

Circumvallate papillae
• 8 to 12 in number
• Adjacent and anterior to
the sulcus terminalis
• Surrounded by a deep
circular group into which
open the ducts of minor
salivary glands.
• Epithelium covering the
lateral walls is non
keratinised and contains
taste buds.

Lingual Tonsils
• Situated near the mid line on the dorsum of
the tongue just behind the vallate papillae.
• Is a lymphoid tissue similar to the palatine
tonsil.
• Infection in this part of tongue will involve
the tonsils. Therefore it is an important
indicator of tonsillar infections.

• Defined as a specialized
receptor that occurs in
the oral cavity, pharynx
and within the
epithelium soft palate.
• Most of them are found
in fungi form, foliate and
CV papilla of the
tongue.
Taste buds

Histology
• Taste bud is a barrel shaped structure
composed of 30-80 spindle shaped cells.
These cells are separated from the
underlying CT by the basement membrane.
Type 1 & 2 – sustentacular cells
Type 3 – gustatory receptor cells
• Outer surface is covered by flat epithelial
cells, which surrounds a small opening.
• Outer supporting cells are arranged like the
staves of a barrel.

• Sweet (at the tip) - fungi form
papillae
• Salt (antero lateral border) –
fungi form papillae
• Bitter (posterior part in the
middle) – CV papillae
• Sour (posterior part in the
lateral areas) – Folliate
papillae.
• Special type of receptor whose
function is to detect the taste of
water has been identified in the
region of CV papillae.
Primary taste sensation

Gustatory path way

Blood supply
• It is chiefly derived from the lingual artery,
a branch of external carotid artery.
• The root of the tongue is also supplied by
tonsillar and ascending pharyngeal arteries.

• Motor nerve: All the intrinsic and extrinsic
muscles of the tongue except palatoglossus by 12th
cranial nerve. Palatoglossus is supplied by
cranial part of the accessory through the
pharyngeal complex.
• General sensation - Lingual nerve.
• Taste sensation - Chorda tympani for the anterior
two thirds of the tongue.
• Glossopharyngeal for the posterior one third and
also for the general sensation.
• Posterior most part is supplied by the vagus
through the internal laryngeal nerve
Nerve supply

• Nutritional deficiencies
• Pernicious anemia
• Vitamin B complex
deficiency
• Diabetes mellitus
ANOMALIES OF TONGUE

• Impairment of local
immune mechanisms
where the langerhan’s
cells are decreased.
• Impairment of local
blood supply
• Fungal infections

• Tongue in tertiary
syphillis is affected by
gumma formation or a
more diffuse chronic
granulomatous lesion –
interstitial glossitis.
• Tongue exhibits non
ulcerating irregular
indurations with an
asymmetric pattern of
grooves covering the
entire dorsun.
• Interstitial glossitis

• Rounded or roughly
lozenge shaped, raised
area that occurs in the
midline of the tongue
dorsum.
• Anterior to the vallate
papilla, affected area
is devoid of filliform
papillae.
• Median rhomboid glossitis

• Lesion of unknown etiology.
It may be related to
emotional stress.
• Desquamation of the
filliform papillae in an
irregular circinate pattern.
• Margins of the lesion are
hyperkeratotic and
acanthotic in some areas.
• Treatment is empirical.
• Geographic tongue

• Characterized by
hypertrophy of the
filliform papillae with
lack of normal
desquamation.
• Fungal infections may
incite this condition.
• Oral use of certain
drugs like pencilin,
aureomycin may
incite this condition.
• Hairy tongue

• Clinically manifested by
numerous small furrows
or grooves often
radiating from a central
groove along the midline
on the dorsal surface.
• Develop simultaneously
as a sequel to geographic
tongue.
• Fissured tongue

• Tongue tie is defined on
the basis of inability to
extend the tip of the
tongue beyond the
vermillion border of the
lip.
• Syndromes
orofacial digital syndrome
trisomy 13
vanderwoode’s
glossopalatine ankylosis
Ankyloglossia

• Causes
• Down’s syndrome
• Congenital lymphangioma
• Congenital hypothyroidism
• Neurofibromatosis type 1
• Pompe’s disease
• Hurler syndrome
• Beckwith’s hypoglycemic
syndrome.
• hyperpituitarism
Macroglossia

• Abnormalities of taste
• Ageusia
Complete
Partial
• Hypogeusia
• Dysgeusia
• Cacogeusia
• Torquegeusia
• Gustatory agnosia – loss of ability to classify
contrast or identify a given taste stimulus

• Ask the patient to protrude the tongue on to
gauze
• Aided bye the gauze dentist can hold the
tongue while using the mirror to observe
• Palpation of the tongue should be done
both left to right and vice versa
• The targeted areas are the lateral borders
and the region of valate papillae
Clinical examination of tongue

Position of tongue
• Tongue position is important to the prognosis of the
mandibular denture.
• Classification of tongue position :
• Class I
• Tongue lies in the floor of the mouth with the tip forward
and slightly below the incisal edges of the mandibular
teeth.
• Class II
• Tongue is flattened and broadened but the tip is in the
normal position.
• Class III
• Tongue is retracted and depressed into the floor of the
mouth with the tip curled upward,downward or
assimilated into the body of the tongue.

• Clinical importance
• Due to long term edentulousness tongue will
expand, introduction of a new denture will be met
with dislodging competition from the tongue.
• Repeated guiding and tongue exercise will help in
altering the size to some extent, over a period of
time tongue will adapt to the new environment.
• Surgical trimming has been used to reduce the
bulk of tissue present in severe cases.

• Severe degree of ankyloglosia exhibit midline
mandibular diastema and lingual mandibular
periodontal defects.
• Difficulty in making the impression which
hampers the retention of denture.
• Altered speech
• Correction
• Mild – speech therapy
• Severe – clipping of frenum

Role of the tongue in speech
• Speech adaptation to new complete dentures
normally takes 2 to 4 weeks after insertion.
• Sounds like this,that,these are made with the tip
of the tongue extending slightly between the
upper and lower teeth.
• This will provide for labio lingual positioning of
the anterior teeth.
• If about 3 mm of tip is not visible, the anterior
teeth are probably too forward in placement.
• Also if the vertical overlap is excess that does not
allow sufficient space for the tongue to protrude
between the anterior teeth.

• Linguo alveolar sounds: t,d,s,z,v&l
While pronouncing these sounds the tip of the tongue
touches the anterior part of the palate. This determines the
thickness of the denture base. If the denture base is too
thick, the patient is forced to pronounce the sounds in a
shallow blunt manner.
• Sibilant sounds:
S- It’s articulation is mainly influenced by the teeth and
palatal part of the maxillary prosthesis.
The tongue’s anterior dorsum forms a narrow groove near
the mid line with a cross section of about 10 mm.The size
and shape of the space will determine the quality of the
sound.
If the opening is too small- a whistle is heard.
If the space is too broad- a lisp is heard.

Prosthodontic considerations
• Lingual surfaces of the lingual flanges should
slope toward the center of the mouth so the
tongue can fit against them and perfect the border
seal on the lingual side of the denture.
• Base of the tongue also serve as an emergency
retentive force for maxillary denture during
incision of food by the anterior teeth .

• Patients whose tongue normally rest in a
retracted position relatively to the lower
anterior teeth should attempt to position the
tongue farther forward so it rests on the
lingual surfaces of the lower anterior teeth.
This will help to develop stability for the
lower denture.

conclusion
• Proper guidance of patient and understanding of
tongue positions during speech is valuable.
• Dentists should have an appreciation of tooth
position, palatal contours, and lingual contours of
the mandibular denture, and these should be
technically addressed at try-in and insertion ,
rather than complete reliance on patient
adaptation

• Bibliography
• Human embryology – I.B.singh 7th Edition
• Human Anatomy – B.D.Chaurasia Vol 3
• Oral Histology – A.R.Tencate 10th
Edition
• Oral Histology – Orban 5th
Edition
• Human Physiology – Guyton 8th
Edition
• Treatment for edentulous patients– Carl O
Boucher 10th
Edition
• Text Book on Complete Dentures – John Joseph
Sharry

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