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RADIOGRAPHIC TECHNIQUES
DR SAMY I AL-AGHA
A.PROFESSOR OF RADIOLOGY
AL-AZHAR –GAZA UNIVERCITY
RADIOGRAPHIC TECHNIQUES
CLASSIFICATION
A-Periapical
B-Bite-wing
C-Occlusal
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
1-BISECTING ANGLE TECNIQUE
A-Patient,s position
For maxillary teeth>>>ala tragus line is parallel
to floor
For mandibular teeth>>>line from tragus to
corner of mouth is parallel to floor
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
B-Film placement:
 Tube side of the film packetis towards the tube.
 The film(short dimension) is parallel to occlusal
plane(For anterior region)
 The film (long dimension) is parallel to occlusal
plane(For posterior region)
 Avoid over-bending of film packet
 The area of interest is in the center of film.
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
 2-3mm of film packet should be left beyond the
occlusal plane
 The patient holds the packet with finger
 Avoid movements of patient,film,or cone during
exposure.
C-Cone,s position:
1-Central ray(C.R)angulation
a-V.A
b-H.A
2-Point of entry
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
Vertical angulation
Denotes the angle between C.R&occlusal
plane
Vertical angle of maxillary teeth(+ve)
Incisors>>>>>>55-60
Canines>>>>>>45-50
Premolars>>>>35-40
Molars>>>>>>25-30
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
V.A for mandibular teeth(-ve)
Incisors>>>>>>15-20
Canines>>>>>>10-15
Premolars>>>>5-10
Molars>>>>>>0-5
Increase V.A 5 in a-shallow palate or floor of
mouth
b-flat ridges(edentulous pt)
c-inclined teeth
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
Decrease V.A 5 in case
a-high palate
b-deep floor of mouth
Horizontal angulation
It is the angle between CR&mid-sagittal plane
It control width(dimention of tooth)
CR must project through interproximal
surfaces of examined teeth
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
H.A
Incisor>>>>>zero
Canines>>>>45-60
Premolars>>>60-70
Molars>>>>>>90
Point of entry
The cone is positioned so that CR is directed
to apices of the teeth
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
For maxillary teeth>>>points of entry are
located on ALA TRAGUS LINE
Incisors>>>>>tip of the nose
Canines>>>>>0.2cm distal to ala of nose
Premolars>>>vertical line from eye pupil to
ala tragus line
1st Molar>>>>vertical line from outer canthus
to ala tragus line
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
2nd Molar>>>vertical line from 1cm distal of
outer canthus to ala tragus line
3rd Molar>>>>vertical line from 2cm distal
of outer canthus to ala tragus line
For mandibular teeth >>>the same as for
maxillary teeth but located on a line
0.5cmabove inferior border of the mandible
Time of exposure depends on area of
rediographed,KV,mA, film speed&age of Pt
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
Advantages of bisecting angle technique
1-Easy,quick &comfortable
2-Used in all patients
3-short object-source distance>decrese exp time
4-periapical area can be demonstrated
5-Speed technique
Disadvantages: 1-Not standerdized
2-error of
angulation>>>superimpositionof structures over
the area of interest
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
2-The paralleling technique(long cone tech) or
Right angle technique
 C.R is perpendicular to both film &tooth
 The film is placed in mid of oral cavity to get
parallism between tooth&film>>>image
magnification&unsharpness.
 Target-object distance is increased to avoid
unsharpness(16 inches)>>>increase KV,mA,s and
fast film(increase exposure time 4times)
 Film holders are used.
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
FILM HOLDERS:
1-Rinn instrument 2-Bite block
3-hemostat
4-Cotton rolls
5-Precision rectangular collimating instrument
Advantages of film holders
1-Provide parallism 2-Avoid exposure to Pt fing
Disadvantages
1-Closure of mouth before exposure
2-Cannot examin the periapical structures
3-Limited in small mouths or gagging sesation
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
ADVANTAGES OF PARALLELING TECHNIQUE
1-Standerdized>>>used in research
2-Accurate images
3-Avoids superimposition on apices
4-H.A&V.A detrmined by positioning devices
5-No overbending of films
PERIAPICAL RADIOGRAPHIC
TECHNIQUES
DISADVANTAGES OF PARALLELING TECHNIQUE
1-Difficult to image all parts of the mouth
2-Increased exposure time
3-Need long cones &film holders
4-Cannot image apical area in shallow palate
5-Discomfort of film holder
6-Time consuming
BITE-WING TECHNIQUE
Used mainly for posterior teeth.
The wing is on the tube side of film backet.
Film backet is parallel to long axis of coronal
portion of upper &lower teeth.
CR is perpendicular to center of film
BITE-WING TECHNIQUE
TECHNIQUE
MSP is perpendicular to floor&ala tragus line is
parallel to floor
Remove any metallic objects.
Patient should close mouth during exposure.
For premolar teeth >>>the film bite should be
centered over the lower 2nd premolar &anterior
border of the film extends anteriorly beyond
the lower canine and 1st premolar.
BITE-WING TECHNIQUE
For molar teeth>>>the posterior border of
film is behind the distal surface of most
posteriorly erupted molar &the film bite is
centered over the lower molar teeth.
The patient should close his mouth in centric
occlusion when radiography of posterior teeth
In edentulous patient replace missing teeth by
cotton rolls
BITE-WING TECHNIQUE
In anterior bitewing film we shoul use
1-smaller film size
2-short dimension is parallel to occlusal plane
3-patient closes his mouth in edge to edge
position
4-longer wing to avoid bending of film
BITE-WING TECHNIQUE
CONE POSITION
CR IS PERPENDICULAR to film packet.
+ve 5 for premolar &10 for molar(short cone)
+ve 6 for premolar &8 for molar (long cone)
For posterior teeth use 2 films
For anterior teeth use 3 films
PANORAMIC RADIOGRAPHY
Produces radiographs for only one section
(slice) of the patient.
Patient is placed so that dental arches are
located in the middle of focal plane.
Patient places edges of incissors in bite block
device.
MSP in midline position.
Patient,s occlusal plane is lowered 20-30
degrees below horizontal plane.
PANORAMIC RADIOGRAPHY
Patient,s back is in erect position with
extended neck.
Patient should hold tongue in contact with
hard palate &keep lips closed during exposure
Patient,s breathing is shallow during exposure
PANORAMIC RADIOGRAPHY
INDICATIONS
1-Evaluation of truama &3rd molars.
2-Evaluation of teeth development.
3-Evalution of developmental anomaly.
4-Examination of maxillary sinuses.
PANORAMIC RADIOGRAPHY
ADVANTAGES:
1. Imaging broad anatomic region.
2. Relative low radiation dose.
3. Convenient,easy &speedy.
DISADVANTAGES:
1. Fine anatomic details are not demonstrated.
2. Magnification,geometric
distortion&overlapping of teeth.
3. High cost.
EXTRA-ORAL TECHNIQUES
1-Lateral views:
a-True lateral b-Lateral oblique
2-PA views:
a-True PA
b-Sinus(Water,s view)
c-Reversed Town,s view
3-AP views:
a-True AP
b-Modified Town,s
c-SMV
d-Frontal TMJ(transorbital)
LATERAL VIEW
LATERAL OBLIQUE
TRUE PA
TRUE PA FOR MANDIBLE
AP SKULL FOR TMJ
SINUS(WATER,S)VIEW
REVERSE TOWN VIEW
TOWN VIEW
SMV VIEW
PANORAMA
TMJ
END