Intra oral xray

what does IOPA stand for

Intra oral periapical projections

2 types of IOPA commonly used

Paralleling technique
Bisecting angle technique

paralleling technique is also known as

Right-angle technique
Long-cone technique

Characteristics of paralleling technique

-Provides less distorted view of dentition
-Most appropriate for digital imaging
-Head position not critical

what imaging technique is most appropriate for digital imaging

Paralleling IOPA

Head position in paralleling IOPA

Not critical - No matter the head position, accurate alignment of cone & film can be obtained

what allows accurate alignment of cone & film in paralleling IOPA

Aiming ring

explain the Paralleling IOPA technique

-X-ray receptor supported parallel to long axis of teeth
-Central ray of X-ray beam is directed at right angle to teeth & receptor

Name of Receptor holder in Paralleling technique

XCP-extension cone

XCP (Extension Cone Paralleling) are

color coded

The Blue XCP is used for:

Anteriors

The Yellow XCP is used for:

Posteriors

The Red XCP is used for:

Bitewing
(half upper arch, half lower)

The Green XCP is used for:

Endodontics

Name of paralleling technique holders for Digital censors

CCD and CMOS (blue & white)

Maxillary Receptor placement (paralleling technique)

Superior border of receptor rests at hight of palatal vault in midline

Mandibular Receptor placement (paralleling technique)

Inferior border of receptor rests on floor of mouth away from mucosa on lingual surface of mandible

Receptor angulation of Maxillary images (paralleling)

always POSITIVE (pointing downwards)

Receptor angulation of Mandibular images (paralleling)

always NEGATIVE (pointing upwards)

Paralleling technique- Maxillary central incisors

Paralleling technique- Maxillary lateral incisors

Paralleling technique- maxillary canines

canine is one of the hardest to image, due to length of root & position in arch

Paralleling technique- Maxillary premolars

Paralleling technique- Maxillary molars

Paralleling technique- Mandibular central & lateral incisors

mand centrals & laterals can be fit into 1 radiograph due to smaller size (unlike max, that need 2 separate ones)

Paralleling technique- Mandibular canines

mandibular canine is harder than maxillary canine because receptor needs to be pushed on floor of mouth \= risk of gage reflex

Paralleling technique- Mandibular premolars

Paralleling technique- Mandibular molars

for anterior teeth, film is placed

Vertically

for posterior teeth, film is placed

Horizontally

advantages of paralleling technique

-Minimal geometric distortion (True Anatomic Relationship)
-Increased image sharpness with minimal magnification (long source-to-object distance, reduces size of focal spots)
-Easier to standardize (aiming device\= same position every appointment)

Disadvantages of paralleling technique

receptor placement, discomfort

If there are anatomic constraints (eg. palate & floor of mouth), what IOPA technique is recommended

Bisecting-angle technique

When was the bisecting technique often used

first 1/2 of 20th century (has been largely replaced by paralleling)

when is bisecting technique useful

when operator is unable to apply paralleling technique due to large rigid sensors or anatomy of patient

explain Bisecting angle technique

aiming central ray of x-ray at right angles to imaginary line that bisects angle formed by long axis of tooth and plane of receptor

what is Cyzynki's theorem

2 triangles are equal when they share 1 complete side and have 2 equal angles

Name of receptor holder in bisecting angle technique

Snap-A-Ray

receptor holder in bisecting technique for Digital censor

Purple & white

Patient position (bisecting angle) \= Maxillary arch

head upright with sagittal plane vertical & occlusal plane horizontal

Patient position (bisecting angle) \= Mandibular arch

head tilted back slightly to compensate for the changed occlusal plane when mouth is opened

Where is the receptor placed in bisecting angle technique

behind area of interest, with apical end against mucosa on lingual or palatal surface

what is the central ray CR

ray that exists from center of PID (position indicating device)

cone points \___ in maxillary imaging

cone points downwards (positive degree angulation)

cone points \___ in mandibular imaging

cone points upwards (negative degree angulation)

Point of entry of CR for Mandibular incisors

Mentum

Point of entry of CR for Mandibular canine

intersection between perpendicular line drawn downwards from commissure of lips & 2nd line drawn 2cms above lower border of mandible

Point of entry of CR for Mandibular premolar

intersection between perpendicular line drawn downwards from pupil of eye & 2nd line drawn 2 cms above lower border of mandible

Point of entry of CR for Maxillary incisors

Tip of nose

Point of entry of CR for Maxillary canine

Ala of nose

Point of entry of CR for Maxillary premolar

intersection between ala tragal line & perpendicular line drawn downwards from pupil

Point of entry of CR for Maxillary molar

intersection between ala tragal line & perpendicular line drawn downwards from outer canthus

Angulation of maxillary incisors

+40

Angulation of maxillary canine

+45

Angulation of maxillary premolar

+30

Angulation of maxillary molar

+20

Angulation of mandibular incisors

-15

Angulation of mandibular canine

-20

Angulation of mandibular premolar

-10

Angulation of mandibular molar

-5

Disadvantages of bisecting angle technique

Without an external guide to position receptor, x-ray beam may miss part of receptor \= Partial image (CONE CUT)

why is bitewing called that

because of the small wing attached to intraoral packet

modern bitewing techniques use

holders (wing now termed tab)

Types of bitewing

Adult bitewing
Child bitewing
Horizontal bitewing
Vertical bitewing

angulation of bitewing

+5 to +10 degree downward vertical angulation

name of beam aiming devices for bitewing

Rinn XCP system

Indications of bitewing

-Proximal caries
-Interproximal bone caries
-Overhanging restorations
-Secondary recurrent caries
-Interproximal calculus

why is occlusal radiography called so

because the patient bites (occludes) on entire film

size of occlusal film

Size 4
57 x 76 mm \= 3 times more than standard size adult 2 film

classification of maxillary occlusal radiography

-Maxillary anterior occlusal
-Maxillary topographic occlusal
-Maxillary lateral occlusal

Image field of maxillary anterior occlusal

Includes Anterior maxilla
anterior dentition
anterior floor of nasal fossa
teeth from canine to canine

teeth seen from maxillary anterior occlusal

canine to canine

projection of central ray of maxillary anterior occlusal

CR through tip of nose towards midline w/ +45 degree vertical angulation and 0 horizontal angulation

angulation of maxillary anterior occlusal

+45 degree vertical (pointing downwards)
0 degrees horizontal

point of entry of CR in maxillary anterior occlusal

through tip of nose

Image field of maxillary topographic occlusal

Palate
zygomatic process of maxilla
antero-inferior aspects of each antrum
nasolacrimal canals
teeth from 2nd molar to 2nd molar
nasal septum

teeth seen in maxillary topographic occlusal

2nd molar to 2nd molar

projection of CR in maxillary topographic occlusal

vertical angulation of +65 degrees and 0 horizontal angulation to bridge of nose below nasion

angulation of maxillary topographic occlusal

+65 degrees vertically
0 horizontally

point of entry of maxillary topographic occlusal

bridge of nose, below nasion

Image field of maxillary lateral occlusal

Quadrant of alveolar ridge of maxilla
Inferolateral aspect of antrum
Maxillary tuberosity
Teeth from lateral incisor to contralateral third molar
Zygomatic process of maxilla superimposes roots of molar teeth

teeth seen in maxillary lateral occlusal

lateral incisor to contralateral third molar

what superimposes roots of molar teeth

zygomatic process of maxilla superimposes over roots of molar teeth

Maxillary lateral occlusal projection

vertical angulation +60 degrees (to a 2 cm below lateral canthus of eye, directed towards center of receptor)

angulation of maxillary lateral occlusal

+60 degrees vertically

point of entry of CR in maxillary lateral occlusal

2 cm below lateral canthus of eye

Classification of mandibular occlusal radiographs

Mandibular anterior
Mandibular topographic
Mandibular lateral

Image field of mandibular anterior occlusal

Anterior portion of mandible
Canine to canine
Inferior cortical border of mandible

Projection of anterior mandibular occlusal

-10 degrees through chin towards mid of receptor

angulation of mandibular anterior occlusal

-10 degrees \==\> gives -55 degrees angulation of plane of receptor

point of entry of mandibular anterior occlusal

midline through tip of chin

miin ghabiyeh

zbzb lana rafah and marah

image field of mandibular topographic occlusal

Soft tissue of floor of mouth
Lingual & buccal plates of mandible
2nd molar to 2nd molar

exposure time of mand topographic occlusal when examining floor of mouth (eg. sialoliths)

exposure time should be reduced to 1/2 time used to create an image of the mandible

projection of mand topographic occlusal

at midline through floor of mouth approx 3 cm below chin, Right angles to center of receptor

point of entry of mand topographic occlusal

midline through floor of mouth approx 3 cm below chin

image field of mand lateral occlusal

Soft tissue of 1/2 floor of mouth
Buccal & lingual cortical plates of 1/2 of mandible
Lateral incisor to contralateral 3rd molar

exposure time when using mand lateral occlusal when used to image the floor of the mouth

exposure time should be reduced to 1/2 when used to provide an image of the mandible

projection of CR of mand lateral occlusal

perpendicular to center of receptor through point under chin, approx 3 cm posterior to chin & 3cm lateral to midline

point of entry of CR in mand lateral occlusal

3 cm posterior to chin and 3 cm lateral to midline