Radiology - techniques 2 Flashcards
The outcome of xray beam is angled up at the tooth/film?
Elongation
The outcome of xray beam is angled down to the tooth/film?
Fore-shortening
Why do you take bitewings?
- Detect caries
- Monitor caries progression
- Asses periodontal status
- Assess existing restoration
Horizontal bitewing?
- Long axis of film is horizontal
- Demonstrate distal 4 to mesial 8
- Demonstrate crowns and 1/3 roots
Vertical bitewing?
- Long axis of film is vertical
- Demonstrate pre-molars and molars
- Demonstrate more of the roots.
How do you decide when to use horizontal bitewing?
- Caries and perio assessment
How do you decide when to use vertical bitewing?
- Caries assessment
- Perio assessment: When you need to see more of root and supporting bone
Requirements for positioning?
1- Film and object should be parallel
2- Film close to object should be as close as possible
3- X-ray beam perpendicular to object and film
How do we achieve good positioning?
Always use a holder
Types of holder?
Rigid plastic and paper tab
Rigid plastic..
1- Holds film accuratley
2- Assists xray tube positioning
3- Uncomfortable
Paper tab..
1- Comfortable
2- xray positioned by eye
3- Inaccurate positioning
What happens with horizontal overlap?
- Difficult to avoid
- Crowding or tilting of teeth
- Will miss early carious lesions
- Must show ED junction and dentinal half of enamel
What does the vertical angulation cause?
Separation of cusps
Where does the dot go on a peri-apical?
To the crown
