DEN 112 EXAM 1 STUDY GUIDE
Basic goal of exposing x rays - Answers - Obtain an image that is sharp, same size,
same shape as the object being x-rayed
The film is used to capture the Shadow Image
. The angle of the cone (vertical and horizontal) will determine if these factors are
achieved.
What are periapical - Answers - •Captures image of entire tooth, crown and root
•Gets bone level below root tip (apex)
•Used in Endodontics- have to see apex (abscess area)
What are bitewing - Answers - •Captures image of upper and lower arches in biting
position
•Does NOT capture root tip (apex)
•Used for decay detection
•Molar and premolar BW's- most common
Shadow casting 5 principles - Answers - Use smallest source possible- high beam- this
is controlled by manufacturer of machine
The object (tooth) and the source (tubehead) distance should be as LONG as possible-
(long cone best)
. The object (tooth) and film distance should be as SHORT as possible- Paralleling does
NOT do good on this one principle
The film and the long axis of the tooth should be parallel
The source must be directed to the film at a right angle- radiation should strike film at a
perpendicular angle (form a "T")
Paralleling technique - Answers - •Best technique overall- does 4 out of the 5 shadow
casting principles
•When you are learning the technique- always go through the next 4 steps
Step 1 : packet placing - Answers - •Choose correct film size for projection
•Decide if film will be placed vertically or horizontally
•Use mount to help
•White side of film always faces the cone
•Determine which teeth to expose and place film directly behind teeth
•Place film parallel to tooth, even with occlusal surfaces, and in line with arches angle
Step 2: vertical angulation - Answers - •The length of the tubehead should be parallel
with the arm or bar of the XCP
, •Max.- angle more positively
•Mand.- angle flat or more negatively
•Adjust vertical by moving cone up/down
Step 3: Horizontal angulation - Answers - •Line the tube head up with the ring of the
XCP
•The entire ring can touch the XCP but if it does not touch then there must be equal
distance between the ring and the tubehead opening or circle
•Point of entry is different for each type of shot- know where beam should "OPEN" so
that you will not have overlapping teeth
•If there is overlapping then the horizontal angulation is incorrect
Step 4: Centering - Answers - •Make sure the entire ring of the XCP is cover by the
tubehead opening
•If the cone is not centered over the ring- then it results in a cone cut- which will be
blank- not exposed because the cone did not cover film
•Cone circle is 2.75 inches wide
Bitewing projection - Answers - •Similar technique as periapicals- film placement is little
different- still go through same four steps in order
•Bitewings- no root ends- Patient (pt.) Bites on tab placed on film
Step 1- Packet placement BW - Answers - •Decide if you are taking Molar or Premolar
shot- most common area for BW's is posterior teeth
•Place film behind teeth you want- use red set of XCP
Step 2 Vertical Angulation BW - Answers - •There is a set vertical angulation for
Bitewings- will always be between 5 to 10 degrees positive (towards floor). This is
mainly for tab use.
•Very little angulation of cone- almost flat for XCP
•Be sure to check the cone dial
Step 3 Horizontal Angulation BW - Answers - •This is the most important step for
bitewings- if teeth are overlapped- the DDS will not be able to diagnose decay- waste of
film and radiation exposed to pt.
•Aim cone to point of entry- between 1st and 2nd max premolars if premolar BW, and
between 1st and 2nd max molars- if a molar BW
Step 4. Centering BW - Answers - •Just like the step with periapicals- be sure that cone
covers entire film
•Half of cone should be at max. And half at mand. Arch- middle of cone should be at
occlusal plane where pt. Bites
Vertical bitewings - Answers - •If the patient has bone loss- then it is best to take
vertical bitewings
•Same procedure- just turn film to go into mouth vertically instead of horizontally
Basic goal of exposing x rays - Answers - Obtain an image that is sharp, same size,
same shape as the object being x-rayed
The film is used to capture the Shadow Image
. The angle of the cone (vertical and horizontal) will determine if these factors are
achieved.
What are periapical - Answers - •Captures image of entire tooth, crown and root
•Gets bone level below root tip (apex)
•Used in Endodontics- have to see apex (abscess area)
What are bitewing - Answers - •Captures image of upper and lower arches in biting
position
•Does NOT capture root tip (apex)
•Used for decay detection
•Molar and premolar BW's- most common
Shadow casting 5 principles - Answers - Use smallest source possible- high beam- this
is controlled by manufacturer of machine
The object (tooth) and the source (tubehead) distance should be as LONG as possible-
(long cone best)
. The object (tooth) and film distance should be as SHORT as possible- Paralleling does
NOT do good on this one principle
The film and the long axis of the tooth should be parallel
The source must be directed to the film at a right angle- radiation should strike film at a
perpendicular angle (form a "T")
Paralleling technique - Answers - •Best technique overall- does 4 out of the 5 shadow
casting principles
•When you are learning the technique- always go through the next 4 steps
Step 1 : packet placing - Answers - •Choose correct film size for projection
•Decide if film will be placed vertically or horizontally
•Use mount to help
•White side of film always faces the cone
•Determine which teeth to expose and place film directly behind teeth
•Place film parallel to tooth, even with occlusal surfaces, and in line with arches angle
Step 2: vertical angulation - Answers - •The length of the tubehead should be parallel
with the arm or bar of the XCP
, •Max.- angle more positively
•Mand.- angle flat or more negatively
•Adjust vertical by moving cone up/down
Step 3: Horizontal angulation - Answers - •Line the tube head up with the ring of the
XCP
•The entire ring can touch the XCP but if it does not touch then there must be equal
distance between the ring and the tubehead opening or circle
•Point of entry is different for each type of shot- know where beam should "OPEN" so
that you will not have overlapping teeth
•If there is overlapping then the horizontal angulation is incorrect
Step 4: Centering - Answers - •Make sure the entire ring of the XCP is cover by the
tubehead opening
•If the cone is not centered over the ring- then it results in a cone cut- which will be
blank- not exposed because the cone did not cover film
•Cone circle is 2.75 inches wide
Bitewing projection - Answers - •Similar technique as periapicals- film placement is little
different- still go through same four steps in order
•Bitewings- no root ends- Patient (pt.) Bites on tab placed on film
Step 1- Packet placement BW - Answers - •Decide if you are taking Molar or Premolar
shot- most common area for BW's is posterior teeth
•Place film behind teeth you want- use red set of XCP
Step 2 Vertical Angulation BW - Answers - •There is a set vertical angulation for
Bitewings- will always be between 5 to 10 degrees positive (towards floor). This is
mainly for tab use.
•Very little angulation of cone- almost flat for XCP
•Be sure to check the cone dial
Step 3 Horizontal Angulation BW - Answers - •This is the most important step for
bitewings- if teeth are overlapped- the DDS will not be able to diagnose decay- waste of
film and radiation exposed to pt.
•Aim cone to point of entry- between 1st and 2nd max premolars if premolar BW, and
between 1st and 2nd max molars- if a molar BW
Step 4. Centering BW - Answers - •Just like the step with periapicals- be sure that cone
covers entire film
•Half of cone should be at max. And half at mand. Arch- middle of cone should be at
occlusal plane where pt. Bites
Vertical bitewings - Answers - •If the patient has bone loss- then it is best to take
vertical bitewings
•Same procedure- just turn film to go into mouth vertically instead of horizontally
