Bisecting angle Technique Flashcards
The tooth and film packet should be
parallel to one another
The film should be positioned with its long axis vetically for
incisors and canines
The film should be positioned with its long axis horizontally for
premolars and
molars
The positioning should be
reproducible
Two techniques for periapical radiography have been
developed.
- The paralleling technique
- The bisected angle technique
The focal spot (Source of radiation) should
be
small as possible.
The focal spot – Object distance should
be
as long as possible.
The Object – Film distance should be
as small as possible
The long axis of the object & the film planes
should be
parallel.
The X-Ray beam should strike the object &
the film planes________
at right angles.
There should be no movement of the tube, film or patient during exposure.
(Given by Mason & Lincoln)
BISECTING ANGLE TECHNIQUE SYNONYMS
- Short cone
technique
Finger holding
technique
PARALLELING TECHNIQUE SYNONYMS
Long cone
technique.
Right angle
technique.
Extension
paralleling
technique
What is the rule of isometry?
Two triangles are equal if
they have two equal
angles and share a
common side
Bitewing projections shows
Crowns of maxillary and mandibular teeth and adjacent alveolar crest
Occlusal projections
Shows an area of teeth and bone larger than periapical film
It is also called as interproximal radiographs
Bitewing projections
BISECTING TECHNIQUE
Use of film holder is not mandatory
Rinn BAI
Stable bite block
Snap-A-Ray
PARALLELING TECHNIQUE
Use of film holder is mandatory
Rinn XCP
Precision film
holders
Grip film holder
Hemostat with bite
block
Indications of Bitewing Projection
- DETECTION OF INTERPROXIMAL CARIES
-MONITORING PROGRESSION OF DENTAL CARIES
-DETECTION OF SECONDARY CARIES BELOW RESTORATIONS
-EVALUATING PERIODONTAL CONDITIONS.
Exposure sequence (number of films depends on;
- curvature of arch
- number of teeth present
The film is place in mouth ______ to the crowns of both the _____ and _____ teeth
Parallel, Upper and Lower
The central ray of the x-ray beam is directed through the contacts of the teeth, using a ______
+10 vertical angulation
(SIZE OF FILM) It is a longer and narrower film used only for bitewing radiographs and spares horizontally from premolar to molar area results in overlapping of the contacts
size 3
If the bitewing holder is used, the aiming ring indicates the ________
Proper PID angulations
If the bitewing tab is used, then both the_________ and ________ angulation must be ____________
Horizontal and Vertical. Precisely determined
The central ray is perpendicular to the curvature of the arch and through the contact areas of teeth
Horizontal Angulations
The central ray is perpendicular to the long axis of tooth, a 10+ vertical angulation is recommended for the bitewing radiograph.
Vertical angulations
Patient Positioning device and angulations patient positioning
-Patient is seated upright the chair adjusted to a comfortable working position
- Secure the lead apron and thyroid collar
- Remove all foreign objects from the face and mouth
Basic rules of bitewing techniques.
The film must be placed to cover the prescribed area
FILM PLACEMENT
The film must be positioned parallel to the crowns of both the upper and lower teeth and stabilized by biting on the film holder or tab
Film Position
The central ray must be directed at +10
Vertical angulation
The central ray must be directed through the contact area between the teeth
Horizontal Angulation
The x-ray beam must be centered on the film to ensure that all the areas of the film are exposed and thus partial image or cone cut is avoided
Film exposure
Advantages of film holder
-Avoiding coming of the anterior part of the film
- All parts of the holder are autoclavable.
-Film packet can be held firmly and cannot be displaced by the tounge.
What is the used of film holders?
To stabilized the film
It is a modified of Rinn-XCP film holder used in periapical radiography
Benn Reproducible film packet holder
Disadvantages of Benn Reproducible film packet holder
- Expensive
-Not suitable for children and adult bitewing
-Positioning of the holder can be uncomfortable for the patient
It is made up of paper loop
Bite Tab
Advantages of Bite tab
-Simple
-Not expensive
-Disposable
-Can be used easily in children
Disadvantages of bite tab
-Coming off the anterior part of film
-The tongue can be easily displace the film packet
This technique is used to examine large areas of upper and lower jaw, palate and floor of the mouth.
OCCLUSAL RADIOGRAPHY
Indications of occlusal radiogrpahy
- To locate retained roots of extracted teeth
- To locate foreign bodies in either jaws
-To locate salivary stones in Wharton’s duct at the floor of the mouth.
-To examine area of cleft palate
-To evaluate boundaries of the maxillary sinus
Classification of both Maxillary and Mandibular
-Topographic/anterior
-Cross sectional
-Lateral
Basic Principle of Occlusal Radiography
-Film is stabilized when patient bites on surface of film
-Film is positioned with white side facing the arch
ANGULATION (VIEWS)
CROSS SECTIONAL ( MAXILLARY AND MANDIBULAR)
MAXILLARY = +65
MANDIBULAR = 90
ANGULATION (VIEWS)
TOPOGRAPHIC (MAXILLARY AND MANDIBULAR)
MAXILLARY = +45
MANDIBULAR = -10
ANGULATION (VIEWS)
LATERAL (MAXILLARY AND MANDIBULAR)
MAXILLARY = +60
MANDIBULAR =-55
3X LARGER THAN SIZE 2 FILMS (57 X 76 MM)
OCCLUSAL FILM
Maxillary cross-sectional view
This projection shows the palate, zygomatic process of maxilla, anterior of each etc
Image field
Maxillary cross-sectional view
The film is placed crosswise into the mouth and gently pushed back until it contacts the anterior boarder of rami
Film placement
Maxillary cross-sectional view
Generally central ray enters the patient’s face through the bridge of the nose
Projections of the central ray
- This projection shows the anterior maxilla and its dentition
-It also includes anterior floor of nasal fossa and the teeth from canine to canine
Image field
The film is placed with exposure side towards the maxilla and long dimension crosswise in the mouth
Film placement
- The central ray is directed towards the middle of the film, The vertical angulation is +65 and horizontal angulation is 0
-Generally central ray enters the patients face through the tip of nose
Projections of the central ray
Anatomical landmarks on maxillary occlusal radiography
-Nasopalatine foramen
-Midpalatine suture
-Incisive foramina
-Hard palate
-Nasal septum
etc
