2. CONTENTS
Introduction
Normal anatomy of the Maxillary Sinus
Examination of the Maxillary Sinus
Radiological Investigations of the Maxillary Sinus
Normal Radiological appearance of the Maxillary Sinus
Radiological Features of the various diseases of the Maxillary Sinus
4. Introduction
An air sinus is an air-
containing space within a bone
Paranasal sinuses- paired, mucosa
lined, air filled cavities of the
craniofacial complex
Present within bones around the
nasal cavity and communicate
with the nasal cavity through its
lateral wall. - ‘Paranasal’ sinuses
• Frontal
• Maxillary
• Sphenoidal
• Ethmoidal
There are four paranasal air
sinuses:-
6. “
○ “Maxillary sinus is the pneumatic
space that is lodged inside the body
of maxilla and that communicates
with the environment by way of the
middle meatus and nasal vestibule.”
6
Drake, Richard; Vogl, A. Wayne; Mitchell, Adam W. M. Gray's Anatomy for Students E-Book London: Churchill Livingstone, 2009
8. 8
Possible relation between dental
pathology and spread of
infection to the maxillary antrum
was described by Scottish
surgeon- Sir John Hunter
9. Development of Maxillary Sinus
• First paranasal sinus to develop
○ 4th month of fetal life: shallow groove between the oral cavity
and the floor of the orbit.
○ At birth: slit like out-pouching of the nasal cavity
○ Develop as an evagination of the mucous membrane of the
lateral wall of the nasal cavity at the level of the middle nasal
meatus forming a minute space that expands primarily in an
inferior direction into the primordium of the maxilla.
○ Grows rapidly by a process known as ‘Pneumatization’ during
the eruption of deciduous teeth
○ Reaches half its adult size by 3yrs of age
○ Reaches full size after eruption of permanent dentition
10. Development of Maxillary Sinus
Courtesy: White SC, Pharaoh MJ. Oral Radiology: principles and Interpretation. 5th ed.St.Louis (US): Mosby/Elsevier; 2004.p.177-180.
11. Development of Maxillary Sinus9-12years
•Antral floor same level
with nasal floor
•Assumes pyramidal
shape
12-18years
•Floor of sinus 5–12.5 mm
below nasal floor
•Dimensions 32-34 mm x
28-33 mm x 23-25 mm
•Volume 15-20 ml
•Floor i.r.t 1st and 2nd
molars and 2nd
premolar
Oldage
•Resorption of ridge –
thinning of sinus wall
•Extension of sinus till
crest
•Anterior & infratemporal
surface reverts to
infantile condition
12. Pneumatization
Courtesy: White SC, Pharaoh MJ. Oral Radiology: principles and Interpretation. 5th ed.St.Louis (US): Mosby/Elsevier; 2004.p.177-180.
Growth of the maxillary
sinus is determined by a
process of bone
remodeling referred to as
pneumatization
Carried out by resorption
of the internal walls
(except the medial wall) at
a rate that lightly exceeds
growth of the maxilla.
• At young age, sinus growth by pneumatization α growth of the maxilla
• With the advance of age, pneumatization exceeds maxillary growth.
• Thus the antrum will expand at the expense of the maxillary process.
13. 13
In old age pneumatization becomes more pronounced, the floor of the sinus moves at more
downward position particularly when the maxillary teeth are lost.
14. Functions Of The Maxillary Sinus
14
Humidification and warming of inspired air
Assisting in regulating intranasal pressure
Lightening the skull to maintain proper head balance
Imparting resonance to the voice
Absorption of shocks to the head
Filtration of the inspired air
(Bailey 1998).
16. Out of all the Paranasal sinuses, Maxillary sinus is the most important for an Oral
Physician due to its close proximity to the roots of maxillary teeth
Nerves that supply maxillary teeth are those that supply the maxillary sinus
accounting for dental pain from healthy teeth arising from maxillary sinusitis
Bone forming the floor of the sinus can also be the bone surrounding the apex of a
tooth. Consequently periapical infection of teeth can spread to maxillary sinus
Pain from carious lesion or other insults to the dental pulp may be referred to the
maxillary sinus.
Accidental communication between the sinus and oral cavity may occur during
tooth extraction or surgical procedures leading to oroantral fistula.
17. Normal Anatomy
○ Located within the body of the maxillary
bone
○ Pyramidal in shape
○ Apex: directed laterally, is formed by
the zygomatic process
○ Base: directed medially, is formed by
the lateral wall of nose
○ Floor: formed by the alveolar
process of the maxilla
18. Anatomical Relations
Mediolaterally
○ Central air-filled cavity
○ Roof: bounded by the orbit
○ Medial wall: bounded by the nasal cavity
○ Lateral wall: related to the zygoma and
cheek
Anteroposteriorly
○ Anterior wall: related to the facial surface
of maxilla
○ Posterior wall: related to the
pterygopalatine fossa
○ Floor: related to the apices of the maxillary
posterior teeth
18
20. Anatomical Relations
○ It communicates with the middle
meatus of the nasal cavity in the lower
part of the hiatus semilunaris through
opening called ostium maxillare
○ It is about 3-6mm in diameter
○ A second opening is usually seen at the
posterior end of the hiatus
20
21. Anatomical Relations
○ The internal surface of the maxillary
sinus may have bony septa that
partially divide it into
intercommunicating compartments
○ Separate ostia may be found in relation
to these compartments
21
22. Maxillary Sinus
• Height (opposite first molar tooth)-3.5cm
• Width-2.5cm
• Antero-posterior depth- 3.25cm
• Average volume -15ml
22
23. Blood Supply
23
The major blood supply of the maxillary sinus is via branches of the
maxillary-artery although the facial artery may make a small
contribution.
The branches of the maxillary artery supplying the maxillary sinus are:
• § Infraorbital artery.
• § Greater palatine artery.
• § Posterosuperior and anterosuperior alveolar arteries.
• § Lateral nasal branches of the sphenopalatine artery.
Venous drainage occurs anteriorly via the anterior facial vein into the
jugular vein orposteriorly via tributaries of the maxillary vein into the
retromandibular vein, which empty into the jugular system.
The region of the infratemporal fossa, the maxillary vein communicates
with the pterygoid venous plexus, which in turn has anastomoses with
the dural
24. Lymphatic Drainage
○ Lymphatic drainage from the maxillary
sinus is relatively poor.
○ Lymphatics from the skin over the
anterolateral wall drains to the
submandibular nodes.
○ From the antrum it drains into
retropharyngeal lymph nodes and then
to the upper deep cervical lymph
nodes
24
25. Histology of Maxillary Sinus
○ Contains air
○ Lined by mucoperiosteum with a
pseudostratified ciliated
columnar epithelium
25
26. Histology of Maxillary Sinus
○ Maxillary sinus is lined by three
layers: epithelial layer, basal
lamina and sub epithelial layer
with periostium.
○ Epithelium is pseudo stratified,
columnar and ciliated.
○ As cilia beats, the mucous on
epithelial surface moves from
sinus interior towards nasal
cavity.
26
28. Palpation
28
Place index finger and
middle fingers on either
side of nose below the rim
of the orbit
If gentle pressure does not
produce pain, percussion
can be carried out
Palpating fingers are
placed in the same position
and the sinus is percussed
using the tip of the middle
finger of the other hand
29. Transilllumination
29
Requirements: Dark room, bright light source
Place the light source in the mouth and press it firmly
against the anterior and lateral aspects of the hard
palate with the patient’s lips closed
Amount of light passing through each sinus is compared
30. Intraoral Examination
○ Intraoral examination should be
performed looking for the following
in upper molar and premolar
region:-
○ Alveolar ulceration
○ Expansion
○ Tenderness
○ Paresthesia
30
33. Periapical Radiograph
○ Radiolucent area above apices of
maxillary molars.
○ Floor appears as a thin radiopaque line
○ Septa appear as radiopaque lines
within the sinus
33
Area of Antrum shown
Base of antral cavity
Relationship with maxillary posterior teeth
34. Periapical Radiograph
Borders of the maxillary sinus appear as a thin, delicate radiopaque line .
(White & Pharoah 2000)
In the absence of disease it appears continuous, but on close examination it has
small interruptions in its smoothness or density.
The roots of maxillary molars usually lie in close apposition to the maxillary sinus
and may project into the floor of the sinus, causing small elevations or
prominences.
34
35. Relation between maxillary posterior
teeth roots and inferior wall of sinus
Acc to Sharan et al
○ 0- the root is not in contact with the cortical
border of sinus
○ 1- an inferiorly curving sinus floor with the
root in contact with the cortical border of
sinus
○ 2- an inferiorly curving sinus floor with the
root projecting laterally on the sinus cavity
but with the root apex outside the sinus
boundary
○ 3- an inferiorly curving sinus floor with the
root apex projecting into the sinus cavity
○ 4- a superiorly curving sinus floor
enveloping part or all of the tooth root
35
Sharan A, Majdar D. Correlation between maxillary sinus floor topography and related root position of posterior teeth using panoramic and cross-sectional computed tomography imaging 2016 3:102 375-381
37. Panoramic Radiograph
37
1. Floor of Maxillary Sinus
1
2
2. Posterior wall maxillary sinus
Area of Antrum shown
Floor
Posterior wall
Base of antral cavity
Relationship with upper posterior teeth
Medial wall
Comparison of both sides
38. Extraoral Landmarks used in
Patient Positioning
○ Median plane of the head (Mid
Sagittal plane): Vertical plane
passing through the mid sagital
suture dividing the skull into two half's.
○ Frankfort horizontal line: This line
passes from the lower most border of
the bony orbit to the upper border of
the external acoustic meatus
38
39. Extraoral Landmarks used in
Patient Positioning
○ Orbitomental line(Canthomeatal
line): Imaginary line from the outer
canthus of the eye to the tragus of
ear.
This is also known as radiographic
base line
39
40. Water’s View
40
Area of Antrum shown
Antral cavity
Roof of the antrum
Lateral and medial wall
Comparison of internal
radiopacities
41. 00 Occipitomental
41
Area of Antrum shown
Main antral cavity
Lateral Wall
Roof or upper border
Medial wall
Allows comparison of both sides
42. True Lateral Skull
42
Area of Antrum shown
Main antral cavity
Posterior wall
Anterior wall
Relation to hard palate and
maxillary posterior teeth
(Note: Superimposition of one antral
shadow on the other)
43. Caldwell View
43
Area of Antrum shown
Medial wall
Mid portion of the antral roof
1- Frontal sinus 2- Ethmoid sinus 3-Petrous
apex
4-Inferior orbital fissure
5-Maxillary sinus obscured by petrous apex
*- Site of anterior ethmoidal artery
45. Systematic approach to
examine the Antra
• Compare antral shadows on both
sides- they should be radiolucent
• Compare the radiodensity of the
antrum on each side with the density of
the soft tissue shadow lateral to it
• The antra should be more radiolucent
• Check the integrity and shape of the
roof and lateral walls
• Also check the medial wall even though
it is the least well defined and difficult
to interpret
45
46. COMPUTED TOMOGRAPHY
46
A-Frontal sinus
B- Ethmoid sinus
C- Maxillary sinus
D- Nasal septum
E- Eye socket
Black- Air
Gray- soft tissue
White- Bone
Area of Antrum shown
Main antral cavity
Floor
All walls
Roof or upper border
Surrounding structures
Allows comparison of both sides
Hard and soft tissue images
49. MRI
49
Coronal T1 weighted
MRI
Axial T1 and T2 weighted MRI
Area of Antrum shown
Main antral cavity
Floor
All walls
Roof or upper border
Surrounding structures
Allows comparison of both sides
Hard and soft tissue images
50. Ultrasonography
○ Ultrasound is becoming the
diagnostic tool of choice for more
and more physicians in detecting
sinusitis.
○ Offers fast, reliable and radiation free
method or diagnosing sinusitis and
has been used successfully in Finland
for around 15 years
○ (Landman 1986)
○ Ultrasound beam sent out by the
sinus ultra is reflected from the
posterior wall of the sinus when the
sinus contains fluid and from the
anterior wall when sinus contains air.
50
51. 51
Periapical (paralleling or
bisected angle technique)
Floor
Base of antral cavity
Relationship with upper
posterior teeth
Panoramic Radiograph Floor
Posterior wall
Base of antral cavity
Relationship with upper
posterior teeth
Medial wall
Allows comparison of both
sides
0° occipitomental
(0° OM)
Main antral cavity
Lateral wall
Roof or upper border
Medial wall
Allows comparison of both
sides
52. 52
Upper Oblique Occlusal Floor
Lower half of antral cavity
Relationship with upper
posterior teeth
True lateral skull Main antral cavity
Posterior wall
Anterior wall
53. 53
Linear or spiral tomography
in coronal or sagittal plane
Main antral cavity
Floor
Anterior wall
Lateral wall
Posterior wall
Medial wall
Roof or upper border
Allows comparison of both sides (coronal only)
Computed tomography
(CT) or MRI
Main antral cavity
Floor
All walls
Roof or upper border
Surrounding structures
Allows comparison of both sides
Images hard and soft tissue
56. Radiology and
Radiography
Radiology : The science or study of radiation as used in medicine, a
branch of medical science that deals with the use of x-rays,
radioactive substances, and other forms of radiant energy in the
diagnosis and treatment of disease
Radiography : The art and science of making radiographs by the
exposure of film to x-rays
Dental Radiography : The production of radiographs of the teeth
and adjacent structures by exposure of film to xrays
Haring JI, Howerton LJ. Dental Radiography : Principles and Techniques. 3rd Ed. Elsevier.
57. Radiology and
Radiography
Radiology : The branch of medicine concerned with the use of
radiation including x-rays and radioactive substances in the
diagnosis and treatment of disease.
Radiography : The technique of examining the body by directing
the x-rays through it to produce images on photographic plates or
fluorescent screens.
L.M Harrison. The Pocket medical Dictionary. 1st ed 1986
58. Radiology and
Radiography
Radiology : The branch of health sciences dealing with radioactive
substances and radiant energy and with diagnosis and treatment
of disease by means of both ionizing and non ionizing radiation
Radiography : The making of film records of internal structures of
the body by passing x-rays or gamma rays through the body to act
on specially sensitized films.
Dorlands. The Pocket medical Dictionary. 1st ed 1995
59. Radiology
Radiology : It is the study and use of radiant energy including
roentgen rays, radium and radioactive isotopes as applied to
medicine and dentistry.
Sikri VK. Fundamentals of Dental Radiology. 1st ed 1992.
60. Maxillary Sinus Lining
60
The lining membrane of paranasal sinuses is a respiratory
mucosa – 1mm thick
When inflamed – increase in thickness 10-15 times
Mucosal membrane thickening greater than 3 mm is most
likely pathologic
Radiographically – radiopaque band more radiopaque than
air filled sinus, paralleling bony wall of sinus
61. Occlusal Radiograph
61
MAXILLARY CROSS SECTIONAL
VIEW
Area of Antrum shown
Antero-inferior aspects of
each antrum
Relationship with upper
posterior teeth
62. Radiography Of
Paranasal Sinuses
○ Radiography of paranasal sinuses
○ Posteroanterior projection (occipito frontal projection of nasal
sinuses)
○ 2 methods for obtaining this
○ Posterior Anterior (Granger projection)
○ Modified Method, inclined posterior anterior (Caldwell
Projection)
○ Radiography of maxillary sinuses
○ Standard occipitomental projection (0° OM)
○ Modified method (30° OM projection)
○ Bregma Menton
○ PA Waters
62
63. Postero-anterior of the skull (PA skull)/
occipitofrontal (OF)
○ The main clinical indications include:
○ • Fractures of the skull vault
○ • Investigation of the frontal sinuses
○ • Conditions affecting the cranium,
particularly:
○ — Paget's disease
○ — multiple myeloma
○ — hyperparathyroidism
○ • Intracranial calcification.
63
65. Caldwell View
65
Area of Antrum shown
Medial wall
Mid portion of the antral roof
1- Frontal sinus 2- Ethmoid sinus 3-Petrous
apex
4-Inferior orbital fissure
5-Maxillary sinus obscured by petrous apex
*- Site of anterior ethmoidal artery
66. 00 Occipitomental
66
Area of Antrum shown
Main antral cavity
Lateral Wall
Roof or upper border
Medial wall
Allows comparison of both sides
Projection taken
with patients
mouth open for
investigation of
sphenoidal
sinus
67. ○ Examine the 0° OM using an
approach based broadly on
that suggested originally by
McGregor & Campbell (1950),
often referred to as Campbell's
lines.
67
69. 30° Occipitomental (30°
OM)
○ This projection also shows the facial
skeleton, but from a different angle
from the 0° OM, enabling certain bony
displacements to be detected.
○ The main clinical indications include:
○ Detecting the following middle third
facial fractures:
○ — LeFortI
○ — Le Fort II
○ — Le Fort III
○ • Coronoid process fractures
69
70. Bregma Menton View
○ This projection used
primarily – walls of
maxillary sinus-
especially in posterior
areas, the orbits, the
zygomatic arches and
the nasal septum
○ Demonstrated medial
or lateral deviations of
the mandible
70
71. Water’s View
71
Area of Antrum shown
Antral cavity
Roof of the antrum
Lateral and medial wall
Comparison of internal
radiopacities
72. Maxillary Sinus Septa
○ First mentioned – Underwood in 1910
○ Formation
Bony septa originating in sinus floor – Underwood Septa.
Divide the sinus into multiple compartments known as posterior recesses.
○ Location
Present in maxillary sinus, act as walls to divide the sinus floor
○ Septa Origin : Classification
Underwood – maxillary sinus floor divided into three basins
Small anterior one over the premolar region
A large median one descending between roots of first and second molars
Small posterior one corresponding to third molar region 72
73. Maxillary Sinus Septa
○ Krenmair et al divided septa into primary and secondary.
○ Primary septa corresponding to those first described by
Underwood, arising from development of maxilla
○ Secondary septa arising from irregular pneumatisation of the sinus
floor following tooth loss
○ Variations with age
○ Other authors classified septa related to the presence/absence of
maxillary teeth.
○ Primary septa located superior to maxillary teeth and secondary
septa located on edentulous maxillae.
73
82. 82
According to Veterans Affairs general medicine clinic study, the accuracy of
diagnosing sinusitis increases to more than 80% if the following criteria are
considered in the water’s view:
1. Presence of air fluid level
2. Sinus opacity
3. Mucosal thickening greater than 6 mm
83. 83
○ The resolution of acute sinusitis
becomes apparent on
radiograph as a gradual
increase in the radiolucency of
the sinus
○ The thickened mucosa
gradually shrinks
○ In time it again becomes
radiographically invisible
○ In chronic sinusitis the
inflammation may stimulate the
sinus periosteum to produce
bone resulting in thick sclerotic
borders of the maxillary antrum
84. Staging of Sinusitis
○ Kennedy’s Staging
○ 1992, based on history, CT finding
and endoscopic appearance
○ Four stages; Stage I, Stage II, Stage
III and Stage IV
84
○ Harvard Staging
○ 1994, similar to Kennedy's
○ Thickening of inflammatory
disease
○ 2mm is normal thickness, anything
more than 2mm is disease
○ Levine and May Staging
○ 1993, considers involvement of
osteomeatal complex
○ Lund-Mackay Staging
○ 1993, most accepted
○ Stage 0: No abnormality
○ Stage 1: Partial Opacification
○ Stage 2 : Total Opacification
86. Retention Pseudocyst
○ Radiographic features
Cysts usually found projecting from the floor of the sinus, though
some form on the lateral walls
Base may be narrow or broad
Dodd and Jing – Mucous cysts are more likely to have a broad base,
serous more pedunculated
Mucous cyst smaller than serous cyst
Mucous cyst associated with thickened mucosa
86
87. Polyp
○ Thickened mucous membrane
○ Maxillary sinus shows radiopacity; which is present despite of
the position in which the radiograph is taken.
○ Usually, the radiopacity has convexity pointing upward
87
88. 88
Pseudocyst Odontogenic cysts
Dome shaped More rounded or tear drop shaped
Lacks corticated border as that of a cyst Floor of antrum is displaced
Corticated border of cyst becomes coincident with
the bony sinus floor
In case of radicular cyst, the lamina dura of involved
tooth is not intact
Pseudocyst Antral polyps
Solitary Often multiple
Adjacent mucous membrane lining is not
apparent
More commonly associated with a thickened
mucous membrane
Benign neoplasms are usually separated from the sinus cavity by a radiopaque border
Malignant neoplasms may destroy the osseous border of the sinus and are less likely to be
dome shaped
89. Anthrolith
• Radiopaque masses having a well
defined periphery which may be
smooth or irregular in shape
• Internal density- Homogenous or
heteogenous
89
Deposition of
mineral salts
Calcium phosphate,
calcium carbonate,
magnesium
Nidus Antrolith
90. Mucocele
• Radiographically : Uniform radiopacity with
a more circular or hydraulic shape
• Bony expansion with thinning of bony walls
• Displacement or resorption of teeth
• Erosion of septa and of bony walls may be
seen 90
Intra antral, intra nasal
inflammation/ polyp/
Neoplasm
Blockage of sinus
ostium
Mucocele
95. Odontogenic Keratocyst
95
Keratocystic odontogenic tumor, maxilla; 16-year-old
male with painless expansion of maxilla,complicated
by sinusitis.
Axial CT image (after biopsy with a drain in place)
shows expansive process in left maxillary sinus
(arrow), multilocular in posterior part (arrowheads).
Axial CT image shows expansion of posterior
thinned sinus wall with cortical defects (arrow), and
fluid.
96. Odontogenic Keratocyst
96
Keratocystic odontogenic tumor, maxilla;
27-year-old female with painless swelling of alveolar process.
Panoramic view shows radiopacity in maxillary sinus (arrow) and radiolucency in right alveolar bone and absent alveolar sinus wall
(arrow).
97. 97
Axial CT image shows scalloped radiolucency in hard palate and alveolar bone
with defect cortical outline (arrow).
Coronal CT image shows mass occupying right maxillary sinus and nasal cavity
(arrow), expanding orbital floor.
98. Large Cysts
98
Odontogenic cysts Sinusitis
Cyst wall is often thicker and more
regular
A cyst that occupies the entire sinus
causes expansion of medial wall of
sinus
Loculation- round shape with a
cortex, appears more radiolucent
than the fluid within the cysts
100. Papilloma
100
Epithelial papilloma is a rare
neoplasm of respiratory
epithelium
Male predilection
Homogeneous radiopaque
mass of soft tissue density
May cause pressure erosion
if bone destruction is
apparent
101. Osteoma
101
This type of mesenchymal
neoplasm of the maxillary
sinuses is ocassionally seen
Incidence vary between 3.9% to
28.5%
Usually appear lobulated or
rounded with a sharply defined
margin
Internal structure is
homogeneous and extremely
radiopaque
Borumandi F, Lukas H, Yousefi B, Gaggl A. Maxillary sinus osteoma: From incidental finding to surgical management. J Oral Maxillofac Pathol 2013;17:318
102. Ameloblastoma
○ Ameloblastoma, solid/multicystic,
maxilla; 80-year-old female with
painless swelling in vestibule and
palate
○ Axial CT image shows scalloped
expansive process with destruction of
palate and cortical bone defects
(arrow)
○ Coronal CT image, soft-tissue window,
shows well-defined soft-tissue mass
without cortical outline palatally or
buccally (arrow)
102
103. Squamous Cell Carcinoma
103
Radiopaque
Destruction of walls of sinus- diagnostic of malignancy
On CT, characteristic sign of malignancy- invasion into the soft
tissue facial planes beyond the sinus walls
CT is helpful in revealing the extent of the neoplasm
Distance between antero-lateral wall of maxilla and coronoid process
of the mandible is measured. If it is increased on one side, it indicates
involvement of infratemporal fossa by the malignancy. This is
called Handousa's sign.
105. Fibrous Dysplasia
○ Posterior maxilla
○ The normally radiolucent maxilla may
be partially or totally replaced by
radiopacity of this lesion
○ ‘ground glass’ appearance on extra
oral radiographs
○ ‘orange peel’ appearance on intra oral
views
105
106. Fibrous Dysplasia
○ Fibrous dysplasia; 23-year-old female with painless swelling of cheek.
○ 3D CT image, of face shows expanded right maxilla and zygoma (arrow)
with elevated orbital floor.
○ Axial CT image shows ground-glass appearance (arrow). 106
107. Pseudotumour
107
Term used for a group of apparently
related diseases of fungal origin that
occur in the paranasal sinuses and in
other parts of head and neck
Radiographic findings include
masses simulating malignant
neoplasms that cause erosion of
bony walls of the involved sinus
CT is done to detect bony destruction,
extent of disease and intracranial
involvement
109. Traumatic Injuries to
Maxillary Sinus
Oro Antral Fistula
○ Oroantral fistula is an abnormal
communication between the oral cavity
and the maxillary sinus.
○ It can result due to several causes such as
extraction of teeth, massive trauma,
surgery to maxillary sinus, osteomyelitis of
maxilla, malignant tumor, infected upper
implant denture, Malignant granuloma
○ Radiograph may show break in continuity of floor
of maxillary sinus
109
110. Traumatic Injuries to
Maxillary Sinus
Root Or Foreign Body In The Antrum
The inadvertent displacement of a root, even a whole
tooth into the maxillary sinus may cause an oro antral
fistula
Following incomplete extraction of a tooth the apical
segment remaining in the socket may be dislodged by
injudicious use of elevators into the sinus
A root tip in the sinus does not have lamina dura around
it. may change its position in the sinus which changes
with patient’s head position. It will not change its
position when it is trapped between the mucosa and
floor of the sinus.
110
111. Traumatic Injuries to
Maxillary Sinus
Blow Out Fracture
Blow to the eye – pressure exerted against orbital
walls
Pressure of blow forces the inferior periorbital
contents (fat and muscle) through the fracture –
become entrapped
Radiographically – opacification of maxillary sinus
with or without fluid level, soft tissue mas sin upper
portion of sinus, image of depressed bone
fragments
In Water’s projection – fractures of the thin walls
are imaged as “bright lines” (white) superimposed
over sinus
111
112. Traumatic Injuries to
Maxillary Sinus
Isolated Fractures
Isolated fractures of paranasal sinuses involve only
a single wall
Radiographs –identified by fracture line “bright line”
Clouding of involved sinus
112
115. Role In Forensics
○ It has been reported that maxillary sinuses remain intact,
although the skull and other bones may be badly disfigured
in victims who are incinerated.
○ Hence maxillary sinuses can be used for identification.
○ Maxillary sinus imaging plays an important role in analysis of
maxillary sinus based on its volume, shape and dimensions to
determine ethnicity and gender
○ It can assist in giving accurate dimensions for which certain
formulae can be applied to determine the gender.
115
117. 117
REFERENCES
• Whaites E. Essentials of Dental Radiography & radiology. 4th
ed. Spain: Churchill Livingstone;2007.
• White SC, Pharoah MJ. Oral Radiology Principles and
Interpretation. 6th ed. India: Elsevier;2010.
• Balaji SM. Textbook of Oral & Maxillofacial Surgery. New Delhi:
Elsevier;2009.
• Chaurasia BD. BD Chaurasia’s Human Anatomy Volume 3. 4th
ed. New Delhi: CBS Publishers & Distributers;2006.
• Bricker SL, Langlais RP, Miller CS. Oral diagnosis, Oral Medicine
and Treatment Planning. 2nd ed. London: BC Decker Inc;2002.
118. 118
REFERENCES
• Karjodkar F. Textbook of Dental & Maxillofacial Radiology. 2nd
ed. New Delhi: Jaypee Brothers Medical Publishers (P) Ltd; 2011.
• .Sharan A, Madjar D. Maxillary sinus pneumatization following
extractions: A radiographic study. Int J Oral Maxillofac
Implants 2008; 23: 48-56.
• Westesson PL, Larheim TA. Maxillofacial imaging. Germany:
Springer; 2006.
• Fernandes CL. Forensic ethnic identification of crania: the
role of the maxillary sinus--a new approach. Am J Forensic
Med Pathol. 2004 Dec;25(4):302-13.
119. 119
• REFERENCES
• Haring JI, Howerton LJ. Dental Radiography : Principles and Techniques.
3rd Ed. Elsevier 2000
• RENNIE, C.; HAFFAJEE, M. R. & SATYAPAL, K. S. Shape, septa and scalloping of
the maxillary sinus. Int. J. Morphol., 35(3):970-978, 2017
• R Fuhrmann, A Bücker, P Diedrich. (1997) Radiological assessment of
artificial bone defects in the floor of the maxillary sinus..
Dentomaxillofacial Radiology 26:2, 112-116.
• Janner SFM, Caversaccio MD, Dubach P, Sendi P, Buser D, Bornstein MM.
Characteristics and dimensions of the Schneiderian membrane: a
radiographic analysis using cone beam computed tomography in
patients referred for dental implant surgery in the posterior
maxilla. Clin. Oral Impl. Res. 2011
120. 120
REFERENCES
• Ohba T, Katayama H. Comparison of panoramic and Waterís
projection in the diagnosis of maxillary sinus disease. Oral Surg
1976;42:534-538
• Waters CA, Waldron CW. Roentgenology of the accessory nasal
sinuses describing a modification of the occipito-frontal position.
• Halstead CL. Mucosal cysts of the maxillary sinus: report of 75 cases. J
Am Dent Assoc 1973;87:1435-1441
• Bretschneider JH, de Visscher JG, van der Waal I. Diseases of the
maxillary sinus: an overview. Ned Tijdschr Tandheelkd. 2012
Apr;119(4):199-204
121. 121
REFERENCES
• Kaplan BA, Kountakis SE. Diagnosis and pathology of unilateral
maxillary sinus opacification with or without evidence of contralateral
disease. Laryngoscope. 2004 Jun;114(6):981-5.
• Roque-Torres GD, Ramirez-Sotelo LR, Vaz SL, Bóscolo SM, Bóscolo FN.
Association between maxillary sinus pathologies and healthy teeth.
Braz J Otorhinolaryngol. 2016 Jan-Feb;82(1):33-8
• An inquiry into the anatomy and pathology of the maxillary sinus. By
ARTHUR S. Underwood
The hiatus semilunaris (or semilunar hiatus) is a crescent-shaped groove in the lateral wall of the nasal cavity just inferior to the ethmoidal bulla. It is the location of the openings for the frontal sinus, maxillary sinus, and anterior ethmoidal sinus.
Eye proptosis is a condition resulting in forward displacement and entrapment of the eye from behind by the eyelids (Exophthalmos)
Ptosis (eyelid) is a drooping of the upper or lower eyelid
Diplopia is double vision
Paresthesia is a sensation of tingling, tickling, prickling, pricking, or burning of a person's skin with no apparent long-term physical effect. The manifestation of a paresthesia may be transient or chronic.
Radiological investigations are basically carried out to study the sinus and their relationship to the surrounding structures.
Routinely the sinus is radiographed with the patient in the erect position, so as to demonstrate the presence or absence of fluid & to differentiate between the shadows caused by the fluids & those caused by other pathology.
The conventional imaging techniques are: Water’s view, standard OM, true lateral skull, caldwell and submentovertex view
Advantages of conventional x-ray imaging include:
1. Cost effectiveness
2. Easy availability
Disadvantages of conventional radiographs:
1. Plain radiographs have a false positive rate of 4% and false negative rate of more than 30%
2. Difficulties in patient positioning
However now there is emergence of advanced imaging modalities like CT, MRI and CBCT
Film size 3x2.3”
Long axis of film is placed parallel to sagittal plane at side of interest
Tube side towards the maxilla. Film is pushed posteriorly till it touches the ramus.
Pt is asked to gently bite to hold the film
Central ray- vertical angulation of +600 2cm below the lateral canthus of eye directed towards centre of film
In this technique the focal trough is positioned on the maxillary sinus
Maxillary sinus is best viewed in water’s view
The maxillary sinus is seen unobstructed by the petrous portion of the temporal bone
Image receptor is placed in front of the patient & perpendicular to mid sagittal plane
Patient’s head is tilted upwards so that canthomeatal line forms a 370 angle with the image receptor
Central beam is directed perpendicular to the image receptor and centered in the area of maxillary sinuses
Exposure Parameters Using Extra Oral Machine Kvp- 70-80 mA-60-50 Seconds -1.6
The cassette is placed in front of the pt perpendicular to the floor in a cassette holding device.
The long axis of the cassette is positioned vertically.
Mid sagittal plane is perpendicular to the plane of film.
Nose and chin should touch the cassette.
Head is tipped back so that canthomental line is 45o to the film.
Central ray is directed horizontally through the occiput
Exposure Parameters using Extraoral machine
Kvp-70-80 mA-60-50 Seconds-1.6
The film is held vertically against the patient’s cheek and centered so that the entire skull along with the facial skeleton, is seen on the resultant radiograph
Pt’s sagittal plane should be vertical and parallel to the film.
The film is adjusted so that the upper circumference of the skull is 1/2 inch below the upper border of the cassette
The pt is asked to keep his/her teeth in occlusion and the occlusal plane should be parallel to the floor.
The central ray is directed perpendicular to the cassette and the midsagittal plane is towards the external auditory meatus.
Exposure Parameters Using Extra Oral Machine
kvp-70-80 mA- 60-50 Seconds -1.6
This view is basically used to demonstrate frontal and ethmoidal sinuses. Maxillary sinus is not clearly visible because the petrous apex obscures its view
However the medial wall of the antrum is best seen in Caldwell
The film is placed perpendicular to the floor in a cassette holding device. The long axis of the cassette is positioned vertically
The mid sagittal plane of the pt is vertical & perpendicular to the cassette. Only the forehead & nose touch the cassette, so that the cantho meatal line is perpendicular to the cassette.
Central ray is directed 23˚to the canthomeatal line, entering the skull about 3 cm above the external occipital protuberance & exiting at the glabella.
Exposure Parameters Using Extra Oral Machine
kvp- 70-80 mA-60-50 Seconds-1.6
The film is placed perpendicular to the floor in a cassette holding device. The long axis of the cassette is placed vertically
The head of the pt is centered on the cassette, with patient’s head and neck tipped back as far as possible.
The vertex (top) of the skull touches the cassette.
The mid sagittal plane should be perpendicular to the plane of the film and radiographic base line should be parallel to the film.
Central beam is directed perpendicular to the film from below the mandible towards the vertex of the skull and centered about 2cm anterior to an imaginary line connecting the right and left condyles
Exposure Parameters using extra oral xray machine
kvp-50 mA- 20-30 Seconds-0.4
CT scan images have replaced conventional x-ray imaging nowadays as they provide multiple sections through the sinuses in different planes
This helps to a better understanding of the extent of disease and in turn helps in arriving at the final diagnosis
In the last decade, a CT system specifically dedicated to the maxillofacial region has been developed and has become increasingly popular.
These cone beam CT (CBCT) scanners capture the entire maxillofacial region by a single rotation of the X-ray tube and detector around the patient’s head while providing sub-millimetre resolution.
Advantageous- radiation dose reduction, less cost
But the disadvantage is the limited availability of this imaging modality to radiologists.
MRI provides a superior visualization of the soft tissues especially the extension of the infiltrating neoplasms into the sinus or surrounding soft tissue
Also helps to differentiate between retained fluid secretions and soft tissue masses in the sinus
On T1 images FAT is white
On T2 images both FAT and WATER are white
Tissues with high fat content (e.g. white matter) appear bright and compartments filled with water (e.g. CSF) appears dark. This is good for demonstrating anatomy.
Compartments filled with water (e.g. CSF compartments) appear bright and tissues with high fat content (e.g. white matter) appear dark.
the Schneiderian membrane may possibly be breached when retrieving a fractured root, it should remain intact for sinus augmentation
The buccofacial wall of the maxillary sinus becomes thicker anteroposteriorly, except in the region of the second molar, and thinner superoinferiorly
The X-ray tubehead is positioned above the patient in the midline, aiming downwards through the bridge of the nose at an angle of 65°-70° to the film packet (see Fi
The patient is positioned facing the film with the head tipped forwards so that the forehead and tip of the nose touch the film — the so-called forehead-nose position.
The X-ray tubehead is positioned with the central ray horizontal (0°) centred through the occiput
This view is basically used to demonstrate frontal and ethmoidal sinuses. Maxillary sinus is not clearly visible because the petrous apex obscures its view
However the medial wall of the antrum is best seen in Caldwell
The film is placed perpendicular to the floor in a cassette holding device. The long axis of the cassette is positioned vertically
The mid sagittal plane of the pt is vertical & perpendicular to the cassette. Only the forehead & nose touch the cassette, so that the cantho meatal line is perpendicular to the cassette.
Central ray is directed 23˚to the canthomeatal line, entering the skull about 3 cm above the external occipital protuberance & exiting at the glabella.
Exposure Parameters Using Extra Oral Machine
kvp- 70-80 mA-60-50 Seconds-1.6
The cassette is placed in front of the pt perpendicular to the floor in a cassette holding device.
The long axis of the cassette is positioned vertically.
Mid sagittal plane is perpendicular to the plane of film.
Nose and chin should touch the cassette.
Head is tipped back so that canthomental line is 45o to the film.
Central ray is directed horizontally through the occiput
Exposure Parameters using Extraoral machine
Kvp-70-80 mA-60-50 Seconds-1.6
Investigation of the maxillary antra
Detecting the following middle third facial
fractures:
— LeFortI
— Le Fort II
— Le Fort III
— Zygomatic complex
— Naso-ethmoidal complex
— Orbital blow-out
Coronoid process fractures
• Investigation of the frontal and ethmoidal
sinuses
Positioning for the 30° OM projection — the patient is in the nose-chin position and the X-ray beam is aimed
downwards at 30°. B Diagram of the positioning — the radiographic baseline is at 45° to the film, and the X-ray beam is aimed
downwards at 30°.
Enters at bregma and exits at menton
Kvp – 65 ma ;10 2-3 seconds
Maxillary sinus is best viewed in water’s view
The maxillary sinus is seen unobstructed by the petrous portion of the temporal bone
Image receptor is placed in front of the patient & perpendicular to mid sagittal plane
Patient’s head is tilted upwards so that canthomeatal line forms a 370 angle with the image receptor
Central beam is directed perpendicular to the image receptor and centered in the area of maxillary sinuses
Exposure Parameters Using Extra Oral Machine Kvp- 70-80 mA-60-50 Seconds -1.6
Diseases of the maxillary sinus are common and may cause symptoms simulating dental disease.
Due to the close relationship between the dental structures and the sinuses it may also be the opposite: dental disease causing sinusitis.
Thus, diseases of the maxillary sinuses are important both in medicine and dentistry.
The diseases of the maxillary sinus can be divided into: Intrinsic and Extrinsic
Intrinsic diseases are the ones that originate from tissues within the sinus
Extrinsic diseases are the ones that originate from surrounding tissues
The mucosal lining of the sinus is about 1mm thick which is normally not visualized on radiographs
But in case of inflammation of the mucosa due to infectious or allergic process, the lining thickness may increase upto 10 to 15times
This is seen on radiograph as thickened mucosa, appearing as a non corticated band which is more radiopaque than the air filled sinus, parallelling the bony wall of sinus
Sinusitis is a condition involving generalized inflammation of the sinus mucosa due to allergen, bacteria or virus.
Based on duration it is classified as: Acute, Subacute and chronic
Radiographically there is thickening of sinus mucosa
The appearance of thickened mucosa helps to differentiate between an allergic reaction and an infection
In case of allergic reaction, the mucosa tends to be more lobulated
In case of infection, the mucosal outline is more smoother with the contour following the sinus wall
Sinus also shows radiopacity due to accumulation of secretion and reduction of air content
Air-fluid level may be observed if the radiograph is taken in "head-up" position. It is not seen in radiograph taken in lying down position. The concavity of fluid opacity points upwards
Also called as antral pseudocyst, mucous retention cyst, retention cyst of the maxillary sinus, benign mucosal cyst of the sinus
These usually form on the floor of the sinus. But some may also form on the lateral walls or roof
They may vary in size from that of a fingertip to completely filling the sinus and making it radiopaque
They appear as a well defined non corticated smooth dome shaped homogeneous radiopaque mass
They shud be differentiated from odontogenic cysts, antral polyps and neoplasms
The thickened mucous membrane of a chronically inflamed sinus frequently results in irregular folds called polyps
These polyps may develop in an isolated area or in a number of areas throughout the sinus
Occurs with a thickened mucous membrane
Maxillary sinus shows radiopacity; which is present despite of the position in which the radiograph is taken. Unlike in cases where fluid is present.
Usually, the radiopacity has convexity pointing upward. Whereas in cases of air fluid level, the concavity points upwards.
Antroliths occur within the maxillary sinus as a result of deposition of mineral salts such as calcium phosphate, calcium carbonate and magnesium around a nidus
The nidus may be introduced into the sinus (extrinsic) or may be intrinsic such as masses of stagnant mucous or cellular debris in sites of previous inflammation
Radiographically they appear as radiopaque masses having a well defined periphery which may be smooth or irregular in shape
The internal density may be heterogeneous or homogenous.
Rarely occurs in the maxillary sinus
It is an expanding destructive lesion that results from a blocked sinus ostium
The blockage may arise due to intra antral or intra nasal inflammation, polyp or neoplasm
When the cavity is filled with pus, it is termed empyema, pyocele or mucopyocele
Radiographically it appears as uniform radiopacity with a more circular or hydraulic shape
Bony expansion is seen with thinning of the bony walls
Displacement or resorption of teeth may be seen
It can be distinguished from a cyst or a neoplasm on the basis of an occluded ostium
Most common group of extrinsic lesions that encroach on to the maxillary sinus
The most common ones are radicular cyst, dentigerous cyst, odontogenic keratocyst
An odontogenic cyst or tumor develops adjacent to the fl oor of a sinus ( I ). As the lesion enlarges, it abuts the maxillary sinus fl oor (II) and ultimately displaces the fl oor superiorly as it enlarges (III). The border of the cyst and the border of the sinus are now the same line of bone.
B, The lesion, as it continues to enlarge, may encroach on almost all the space of the sinus, leaving a small saddlelike sinus over it (arrow). The appearance may mimic sinusitis.
The exudate from dental inflammatory lesions can diffuse through the cortical boundary of the antral floor
These products can elevate the periosteal lining of the cortical bone of the floor of the antrum
This stimulates the periosteum to produce a thin layer of new bone adjacent to the root apex of the involved teeth
The presence of this new bone layer indicates inflammation of the periosteum
Appears as a halo like layer of new bone centered directly above the inflammatory lesion
The cyst has a curved or oval shape defined by a corticated border
The internal structure appears homogeneous and radiopaque
These lesions should be differentiated from retention pseudocysts (Based on cortication. In case of infected cysts cortex may be lost. In such cases the relationship to the neighbouring teeth shud be checked)
\dentigerous cyst appears to expand into sinus, radiolucency elevating and intact wall or floor of the maxillary sinus
Very large cysts may completely cover the sinus cavity and may appear as if the cyst is within the sinus
In such cases it may resemble sinusitis with radiopacification of the sinus
In order to differentiate one must note down tat
Cyst wall is often thicker and more regular than that of a sinus
Vascular markings on wall of maxillary sinus are not present on walls of cysts
A cyst tat occupies the entire sinus causes expansion of medial wall of sinus
The sinus loculation may have a round shape with a cortex. And also it appears more radiolucent than the fluid within the cysts
Benign tumors are rare
radiogrPHIS IMAGES OF BENIGN TUMORS ARE NON SPECIFIC
Involved portion of sinus appears opaque due to presenc eof mass and bone expansion may occue
Malignancies are usually SCCs. Tumors tend to cause bone destruction
It shud be differentiated from antrolith, odontome and odontogenic neoplasms
All these lesions are not as homogeneous appearance as osteoma
19
Arises in premolar molar region and invades sinus cavity at early stage
% occur in maxilla
Cavity filled with soft tissue mass, and walls are eroded
Originates from the metaplastic epithelium of the sinus mucosal lining
Radiographically Sinus is radioopaque.
Sometimes, destruction of walls of sinus is seen and is diagnostic of malignancy
On CT, characteristic sign of malignancy- invasion into the soft tissue facial planes beyond the sinus walls
CT is helpful in revealing the extent of the neoplasm and the extension into the orbit, infratemporal fossa or cranial cavity
Distance between antero-lateral wall of maxilla and coronoid process of the mandible is measured. If it is increased on one side, it indicates involvement of infratemporal fossa by the malignancy. This is called Handousa's sign.
Prognosis of malignancy is determined by position of tumour on basis of Onhgren's line.
Onhgrens line is an imaginary line extending from medial canthus of the eye to the angle of the mandible which divides the maxillary antrum into the infrastructure and suprastructure
Tumours below this line have a better prognosis than tumours above this line.
MRI is useful in these cases for revealing extent of soft tissue penetration into adjacent structures
To differentiate between mucous accumulation and soft tissue mass of neoplasm
Results due to localized changes in normal bone metabolism tat results in replacement of all the components of cancellous bone by fibrous tissue containing varying amount of abnormal appearing bone
This lesion may arise adjacent to the sinus and cause displacement of the sinus borders
Posterior maxilla most common location
The normally radiolucent maxilla may be partially or totally replaced by radiopacity of this lesion
Usually radiopaque areas have ‘ground glass’ appearance on extra oral radiographs and ‘orange peel’ appearance on intra oral views
Also called as invasive fungal sinusitis, mucormycosis, aspergillosis, rhizopus sinusitis
Is the term used for a group of apparently related diseases of fungal origin tat occur in the paranasal sinuses and in other parts of head and neck
Radiographic findings include masses simulating malignant neoplasms tat cause erosion of bony walls of the involved sinus
CT is done to detect bony destruction, extent of disease and intracranial involvemnt
Test to establish the presence of recently created OAF If the fistula is large it will be obvious on simple inspection but if patency of OAF remains in doubt, nose blowing testnose blowing test may be confirmatory. Compression of anterior nares followed by gently blowing down the nose (with mouth open) causes a rise in intra-oral pressure, exhibited by whistling sound, escaping air bubbles, blood or pus may appear at the oral orifice.
Periapical or occlusal radiographs - show a root within the sinus or Break in continuity of floor of antrum shows point of entry. A panoramic radiograph & water's view are also important
Before mastery in analysis of pathological cases, one must be fluent with the normal radiographic anatomy and its variation
Plain film radiographs have substantial limitations inspite of meticulous attention to the technical details
Hence wherever required advanced imaging modalities should be recommended