selection and perception of radiographs

Question 1

periodical radiography seletion

Answer 1

• this would be chosen if the causative tooth is obvious and the patient would like to save it by RCT

Question 2

what would you use if there was swelling and truisms

Answer 2

• this can make getting an x-ray in the mouth difficulty then a sectional panoramic film is recommended (extra oral)
• this should identify obvious caries or apical infection

Question 3

if caries is not obvious

Answer 3

• if it is not obvious then you can use a bitewing radiograph of the symptomatic side (typically shows the premolars and the molars on that side)

Question 4

risk of caries and repetition for screening of caries radiographs

Answer 4

1) low
- 2 years
2) moderate
- 1 year
3) high
- 6 months

Question 5

when are periapcial films recommended

Answer 5

suspect a combined peri-endo lesion

• this is a combination of periapical infection and periapical disease
• allows you to see apical tissues and the bone levels

Question 6

what are radiographs not necessary for

Answer 6

diagnosis of periodontal disease but BPE probe is

• current guidelines state radiographs should be available for all code 3 (4-5mm) and 4 sextants (greater than 6mm)
• can either be a bitewing (horizontal or vertical) or a periapical
• can determine the level of alveolar bone loss using this radiograph

Question 7

endodontic radiographs

Answer 7

1) pre treatment
- allows to estimate length of endodontic instrument
2) guide file
- file to the working length
- 2nd radiograph allows you to check the working length ensure within 1mm of radiographic apex of the root, not too long/short
3) master cone
- 3rd radiograph used to check full length to apex
4) final fill
- take post obturation fill radiograph

• within 12 months of completion root fillings usually fail within this
• so review film is taken about 1 year after completing treatment

Question 8

when should radiographs be used in orthodontics

Answer 8

• when deciduous or permanent teeth need extracting
• to determine the presence of unerupted permanent teeth
• when functional appliances or combined orthodontic/orthognathic surgery is planned

Question 9

pre extraction radiographs

Answer 9

no evidence to support this

- diagnosis is evident then its tneeded

Question 10

when is pre extraction radiographs required

Answer 10

when 3rd molar extractio
root anatomy is not predictabel
- sectional or full panoramic radiograph (OPG)

Question 11

TMJ problems

Answer 11

patients that fail to respond to conservative measures an open mouth panoramic film is worthwhile to confirm the bony anatomy is normal
- for internal derangement of the disc, MRI is needed to make diagnosis (only scan allowing disc to be seen in the joint)

Question 12

best films for trauma investigations

Answer 12

Intra oral periapical or occlusal films are the best examination to identify root or dentoalveolar fractures
- Reduced exposure films are good at identifying tooth fragments lodged in the soft tissues eg lips

Question 13

what views are used to identify facial bone injuries

Answer 13

• Occipitomental (OM) views

Question 14

salivary gland disease

Answer 14

Patients present with symtoms of

• pain and swelling when eating (under lower border of mandible or next to the ear)
  i. e. meal time syndrome
• painfull due to saliva being stuck due to the obstruction and gland surrouneded by fibrous capsule, therefore painful
• can be detected by radiographs but sialgram is better (iodine dye)

Question 15

how to improve percemtopn

Answer 15

1) have the correct attitude
- don’t just take a quick look
- don’t be rushed
2) shut blids/turn off lights
- twilight is best lighting for analysing radiographs
3) know anatomy
4) develop a system for screening the whole image
- avoid tunnel vision
- don’t miss something that is there
5) remember radiographs are 2d images of 3 d objects
- something that appears in bone may not be

Question 16

what does absorption of x ray depend on

Answer 16

• thickness
• density
• atomic number