Paranasal sinuses / dental implant courses

Paranasal sinuses
INDIAN DENTAL ACADEMY
Leader in continuing Dental
Education
www.indiandentalacademy.com

INTRODUCTION
 Paranasal sinuses are air containing spaces around
the nasal cavity.
 They are lined by respiratory mucous membrane of
ciliated coloumnar epithelium.
 4 paired(bilateral) pns are
Frontal
Sphenoidal
Ethmoidal
Maxillary

DEVELOPMENT
 All sinuses have common embryologic origin that’s why
they share common characteristics.
 The sinuses are present in a rudimentary form at birth,
they enlarge appreciably around 7-8 years of life and
become fully formed in adolescence.
 From birth to adult life the growth of the sinuses is due
to the enlargement of the bones, in old age it is due to
resorption of the surrounding cancellous bones.

 Maxillary sinus is the first of the PNS to develop
 During the late somite period (4th week i.u.) the lateral part of
the mesoderm of the ventral foregut region becomes segmented
to form a series of 5 distinct bilateral mesenchymal swellings,
called as pharyngeal arches.

Pharyngeal arches

4 week embryo

4 ½ week embryo

Palatal fusion

Horizontal shift of the palatal shelves and subsequent fusion
with one another
nasal septum separates oral cavity from the two nasal
chambers
Influence further expansion of the lateral nasal wall
and 3 wall begin to fold
3 conchae and 3 meatuses arise

3 meatuses
Superior & inferior meatus Middle meatus
Remain as shallow
depressions along the
lateral nasal wall for first
half of I.U life
Expands immediately
into lateral nasal wall
Expands in an inferior
direction occupying more
of further maxillary body

 Development of sinus starts at 12 weeks as an evagination
of the mucous membrane in the lateral wall of the nose
when the nasal septum invades the maxillar mesenchyme

 Pneumatization is the enlargement of the sinus by resorption
of alveolar bone that forerly serves to support a missing tooth
or teeth and then occupies the edentulous space.

 The early paranasal sinuses expand into the cartilage walls and
roof of the nasal fossa by growth of mucous membrane sacs
(primary pneumatization) into the maxillary sphenoidal, frontal
and ethmoid bone.
 The sinuses enlarge into the bone (secondary pneumatization)
from their initial small outpocketings always retaining
communication with the nasal fossa through ostia.

Development of maxillary sinus
 In its development maxillary sinus is
 Tubular- at birth
 Ovoid in childhood
 Pyramidal in adulthood

BASE
APEX

AT BIRTH
 Maxilla is filled with decidious tooth gems
 Maxillary sinus is a tubular shallow cavity
 Dimensions of the max sinus are
antero-posterior length:7mm
vertical height:4mm
width:4mm
 Expands 3mm anteroposteriorly and 2mm vertically each
year untill 9yrs of age

 The alveolar &orbital process of maxilla are seperated by
cancellous bone, which resorbs as the max sinus enlarges
 Undergo lateral expansion below the orbit by the end of 1st yr
 By the end of 20th month, the maxi sinus develops to the position
of rudimentary permanent 1st molar
 By the end of 2nd yr sinus reaches half its adult size

At 7 yrs
 Dimensions of the max sinus are:
Antero-posterior length:27mm
Vertical height:17mm
Width:18mm
 Sinus grow rapidly as permanent teeth erupt

At 12-15yrs
 Max sinus extends down to the same level as nasal floor
 Surgically accesible via the inferior meatus
Adult sinus floor is centered over
Upper 1st &2nd permanent molar
Upper 2nd premolar
Upper 1st premolar or canine
Posteriorly upto 3rd molar if size is more

DEVELOPMENT OF MAXILLARY SNUS

IN OLD AGE
 In edentulous patients ,alveolus is resorbed and floor of the
sinus becomes thin
 Anterior and infra-temporal surfaces undergo resorption and
maxilla reverse to an inantile condition
 In adults sinus floore lies1.25cm below the floor of the nose
while in children and edentulous it lies at the same level

DEVELOPMENTAL ANAMOLIE
 Agenesis (complete absence) aplasia and hypoplasia (altered
development or under development) of the sinus occurs
eighter alone or in association with other anamolies like
 Cleft palate
 High palate
 Septa deformity
 Absence of conchae
 Mandibular dysostosis
 Malformation of the external nose

FRONTAL SINUS DEVELOPMENT
 the middle meatus invaginates laterally to form the embryonic
infundibulum .
 During the 13th week of development the embryonic
infundibulum grows superiorly to form the frontal recess
area.
 Development of frontal sinus: The frontal sinus may develop
as a direct continuation of embryonic infundibulum and
frontal recess superiorly during the 16th week.
 It can also develop by upward migration of anterior ethmoidal
air cells to penetrate the inferior aspect of the frontal bone
between its outer and inner tables.

 Pneumatization of frontal bone is a very slow
process. The frontal sinus infact remains as a small
blind sac within the frontal bone till the child is
about 2 years of age, then secondary pneumatization
begins.
 From the age of 2 till the child becomes 9 years old
secondary pneumatization of frontal bone proceeds.
 When the child reaches the age of 9, the
development of the frontal sinus has reached
completion.

DEVELOPMENT OF SPHENOID AND ETHMOIDAL SINUS

MAXILLARY SINUS
 The maxillary sinus was first described in 1651,by Nathaniel
highmore . (ANTRUM OF HIGHMORE)
 Maxillary sinus are two in number, one on eighter side of the
maxilla, and they are the largest of the paranasal sinuses.
 They communicate with the other paranasal sinuses through the
lateral wall of the nose.

MAXILLARY SINUS
It is pyramidal in shape with
base- lateral wall of the nose
apex- zygomatic process of maxilla
roof- floor of the orbit
floor –alveolar process of maxilla.
The floor is marked by several conical elevations produced by
the roots of the upper molar and premolar teeth

ROUTE
Maxillary sinus opens into middle meatus through 2 ways
lower part of hiatus semilunaris
Posterior end of the hiatus semilunaris
Both openings are nearer the roof than the floor of the
sinus

Arterial supply: Facial
Infraorbital
Greater palatine
venous drainage: facial vein
pterigoid plexus of veins
Lymphatic drainage: submandibluar nodes
Nerve supply: infraorbital
anterior ,middle and superior alveolar

FRONTAL SINUS
 Two in number
 Located within the frontal bone seperated from eachother by
bony septum
 frontal sinus are rudimentary or absent at birth .they are well
developed between 7&8yrs of age ,but reach full size only after
puberty
 The right and left sinuses are usually unequal in size

 It extends upwards above the medial end of the eyebrow &
backwards into the medial part of the roof of the orbit.
 It opens into the middle meaus of the nose at the anterior end of
the hiatus semilunaris eighter through infundubulum or fronto
nasal duct.

 Arterial supply: Supraorbital artery
 Venous drainage: Anastomatic vein between the supraorbital
and superior ophtalamic veins
 Lymphatic drainage: submandibular nodes
 Nerve supply: supraorbital nerve

ETHMOIDAL SINUS
Ethmoidal sinuses are numerous small intercommunicating
spaces which lies within the ethmoid bone
They are formed
superiorly - orbital plate of the frontal bone
Posteriorly - sphenoid chonchae and the orbital process of
the palatine bone
Anteriorly - lacrimal bone

The sinuses are divided into 3 groups
o Anterior ethmoidal sinus
o Middle ethmoidal sinus
o Posterior ethmoidal sinus

Ethmoidal drainage route

 The anterior ethmoidal sinus is made up of 1 to 11
air cells
 It opens into the anterior part of hiatus
semilunaris
 Supplied by ethmoidal nerve and vessels
Lymphatic drainage:submandibular nodes

 The middle ethmoidal sinus contain 1to 7 air cells opens
into middle meatus of the nose
 Supplied by posterior ethmoidal nerve and vessels and
the orbital branches of pterygopalatine ganglion
 Lyphatics drains into submandibular nodes

 The posterior ethmoidal sinus containing of one to seven
air cells opens into the superior meatus of the nose .
 It is supplied by the posterior ethmoidal nerve and vessels
and the orbital branches of the pterygopalatine ganglion
 Lymphatic drains into the retropharyngeal nodes

SPHENOIDAL SINUS
 The right and left sphenoidal sinuses lie within the body
of the sphenoid bone.
 They are seperated by a septum
 The two sinuses are usually unequal in size
 Each sinus opens into the sphenethmoidal recess

Sphenoidal drainage route

 Arterial supply: posterior ethmoidal and internal carotid
artery
 Venous drainage: pterygoid plexus &cavernous sinus
 Lymphatic drainage: retropharyngeal nodes
 Nerve supply:posterior ethmoidal nerve and orbital
branches of the pterygopalatine ganglion

FUNCTIONS OF PARANASAL SINUSES
 Air conditioning
 Acting as a reservoir
 Aiding in olfaction
 Reduction in weight of cranium
 Addition of resonance to voice
 Protection
 Insulation of cerebrum and orbits
 Participates in the formation of cranium

WATERS VIEW

 Clinical aspects
Inflamatory Diseases
•Sinusitis
•Retentention pseudocyst
•Polyps
•Antrolith
•mucocele
Intrinsic diseases of the paranasal sinuses Extrinsic diseases involving paranasal sinuses
Neoplasms
Osteoma
Malignant
Squamous cell carcinoma
Pseudo tumor
Benign
odontogenic
cysts &tumors
Trumatic
•Dental structures
displaced into the sinus
•Oral anthral fistula
•Fracture of the maxillo
facail skeleton

o SINUSITIS: It is a condition involving generalized inflamation
of the paranasal sinus mucosa
o PANSINUSITIS: Sinusitis effecting all the paranasal sinuses
Sinusitis

Depending on duration it is of 2 types
Acute sinusitis
Chronic sinusitis

CLINICAL FEATURE
o Nasal Obstruction
o Nasal Discharge
o Abnormalities Of Smell
o Headache
o Epistaxis
o Heavy Feeling In The Head
o Reffered pain

INVESTIGATIONS
 Waters view
 Ct scan
Radiographic appeareance:
o The sinuses appear increasingly radiopaque.
o Chronic sinusitis may appear like persistent
radiopacification of the sinus with sclerosis and the
thickening of sinus wall

Treatment
Acute sinusitis: decongestants with antibiotics
Chronic sinusitis: Drainage
Endoscopy

Waters view

FLUID
AIR
AIR-FLUID LEVEL

OROANTRAL FISTULA
 An oroantral perforation is an unwanted communication
between the oral cavity and maxillary sinus

CLINICAL FEATURE
o Escape of fluids
o Epistaxis
o Escape of air
o Enhanced coloumn of air
o Pain
o Nasal discharge
o sinusitis

Various tests
 Nose blowing test
 Cotton test
 Unilateral epistaxis
 Mouth mirror fogging test

Oro Antral Fistula

Treatment
o Small openings(0.5) can be left without treatment
o Large opening need surgical closure

OSTEOMAS
 The osteoma is the most common of the mesenchymal
neoplasm in the paranasal sinus
C/F:
Age: 3rd n 4th decade
Sex predilection: males
Clinical presentation: slow growing
asymptamatic
Nasal obstruction and swelling of the side of the nose
Proptosis
Most commonly seen in frontal & ethmoidal sinuses

Radiographic Fetures
 They appear as radiopaque round or lobulated structure with
well defined margins

ANTHROLITH
 Antroliths are cancellous mass seen in maxillary sinus.
Clinical feature:
Smaller-asymptamatic
If they contiue to grow :
o Sinusitis,
o Blood stained nasal discharge,
o Nasal obstruction
o Facial pain

Radiographic features
 Location: They are present above the floor of the maxillary
antrum
 Periphery & shape: well defined periphery & may have a
smooth or irregular surface
 Internal structure: varies from barely perceptible to an
extremely radiopaque structure

Anthrolith

POLYPS
 The thickened mucus membrane of a chronically inflamed sinus
frequently form into irregular golds called polyps
 clinical feature:
Displacement or destruction of bone
In ethmoidal air cells polyp may cause destruction of the medial
wall of the orbit
Unilateral proptosis

Mucocele
 Synonyms:
Pyocele
mucopyeocele
A mucocele is an expanding destructive lesion that results
from a blocked sinus ostium.

Radiographic Features
Location: Floor of the maxillary sinus
Lateral wall or roof
Periphery and shape: well -defined, noncorticated, smooth
dome shaped radiopaque masses
Internal structure: It is homogeneous and more
radiopaque than the surrounding air of the sinus cavity

CLINCIAL FEATURE
 Radiating pain
 Sensation of fullness of cheek or may swell
 Anterio -inferior aspect of antrum
 Inferior border- loosening of posterior teeth
 Medial wall- lateral nasal wall will deform
 Orbit- diplopia or proptosis

Radiographic features
 Location: Ethmoidal & frontal sinus
 Periphery& shape: more circular “hydraulic "shape as the
mucocele enlarges
 Internal structure: uniformly radiopaque
 Effects on surrounding structure:
Shape of the sinus may change
Septa n bony walls may thinned
Teeth may be resorbed or displaced
Displaces the contents of the orbit

ODONTOGENIC CYSTS
Odontogenic cysts are the common group of extrinsic
lesions that encroach on the maxillary sinus
The most common Radicular cyst
Dentigerous cyst
OKC

Radicular Cyst

Retention Pseudo Cyst
 Synonyms: Antral Pseudo Cyst,benign Mucous
Cyst,mucus Retention Cyst.
It is a pathologic submucosal accumulation of secretions
due to blocakage of secretory ducts of seromucous glansd
in the sinus resulting in swelling of the tissue

Clinical features
 Gender: male
 Nasal obstruction
 Post nasal discharge
 Maxillary sinus is the common site

Retention pseudo c cyst
producing a domeshaped
soft tissue
radiopacity emanating
from the floor of the
maxillary sinus. The
cyst may disappear
spontaneously due to
rupture and may
reappear after a few
days.

BENIGN ODONTOGENIC TUMOR
 AOT

ROOT TIP IN THE MAXILLARY
SINUS

REFERENCES
 B.D chaurasia 3th edition
 Inderbir singh 8th edition text book of human
embryology.
 Text book of oral & maxillofacial surgery Neelima
anilmalik
 Orbans oral embryology and histology.
 Oral radiology principles and interpretation 5th edition
white & pharaoh

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