What is the outer layer of the crown of the tooth called?
What is the hardest stubstance in the body, even harder than bone?
What is the main tissue component of the tooth?
What covers the dentin on the crown of the tooth?
What covers the dentin on the root of the tooth?
Is dentin harder than bone?
What is dentin comprised of?
tubular extension from the pulp
What does the pulp cavity/pulp chamber consist of?
- blood vessels
- connective tissue
What is the living part of the tooth?
pulp cavity/pulp chamber
What happens to the pulp cavity as the animal ages?
becomes progressively more narrow
What part of the tooth is the root?
the portion below the gum line
What is the root covered by?
Which is often longer, the root or the crown?
Where do we often see abcesses?
at the apex of the root
What is a furcation?
the space between the tooth roots where they join the crown
What can lead to the furcation being exposed?
gingival recession due to periodontal disease can lead to the periodontal loss of alveolar bone
How many grades of furcation ar there?
What is the gingival sulcus?
the normal space created by the free gingiva (portion of the gingiva not directly attached to the tooth) and the tooth
What are the periodontal ligaments?
a network of fibers connecting the tooth to the bone
What must happen to the ligament in order to extract the tooth?
the ligament must be "fatigued"
What can destroy the ligament attachment?
What is the alveolar bone?
the bone directly surrounding the tooth roots
What can destroy alveolar bone?
chronic periodontal disease
Why should we do dental radiography?
- to see pathology hiding below the gingiva or inside the tooth
- evaluate an area where the teeth appear to be missing
- client communication
- medical/legal documentation
- postoperative confirmation of extraction
- preoperative, intraoperative, and postoperative endodontics
- follow progression of pulpa pathology and or periodontal disease
- pre-purchase exams for show dogs to make sure they have all their permanent teeth
When do we take a dental radiograph?
- when a tooth is mobile
- when gingiva bleeds with or without probing
- when a tooth is fractured
- when a tooth is discolored
- when furcation exposure is present
- when teeth are missing without explanation
- when a felin ondoclastic resorptive lesion is present
- prior to extraction for anatomical orientation and documentation
What are the 6 dental radiographic views?
- 4 canines
- upper premolars
- lower premolars
- upper molars
- lower molars
When do we do a full mouth (6 view) radiographs?
- when there is periodontal disease
- when feline ondoclastic resorptive lesions are diagnosed
- fracture teeth of unknown origin
- when evaluating the number of secondary teeth in a puppy or kitten before purchasing
- to evaluate oral and facial swelling
Can we use a regular x-ray machine to take dental radiographs?
When using a standard x-ray machine, what should the focal-film distance be?
12 - 16 inches
When using a standard x-ray machine, what should the kVp be?
- 60 kVp for cats/toy breeds
- 70 kVp for medium dogs
- 85 kVp for large dogs
When using a standard x-ray machine, what should the mAs be?
10 - 15 mAs
what are some positioning aids we can use for proper positioning?
_____ focal film distance = less distortion.
What are the different parts to a dental x-ray unit?
What is the PID?
- position indicating device - extension on tube head at collimator attachment
- used to minimize rad exposure
What does the control panel contain?
time, kVp, and Ma regulators
What is the kVp setting range on a dental x-ray unit?
50 - 100 kVp
What does the kVp determine?
determines quality of x-radiation produced
larger teeth require _____ kVp.
What is the typical speed setting for a dental x-ray unit?
What does Ma measure?
What is the common Ma setting for a dental x-ray unit?
between 7 and 15 mA
Moving the tube farther or closer affect what?
the intensity of the x-ray beam
What is the ideal focal film distance for dental radiography?
10 - 12 inches
The closer the object being radiographed is to the film, the _____ the image.
How far away from the patient do we need to stand when taking a dental radiograph?
at least 6 feet away and not directly in front of the beam
Do we need to wear our x-ray badge when taking dental x-rays?
What does radiation do to our bodies?
damages cellular DNA
What are the three things we need to do remember when minimizing exposure the us and the patient?
When using intraoral film, exposure time ranges from _______ seconds.
1/12 - 1/10
Does digital dental radiography use lower exposure times?
yes, but the reduction can be negated by increased number of retakes
The shorter the focal film distance the _____ scatter.
The furthest away you stand from the tube, the _____ radiation you will be exposed to.
Should you use your hands to hold the film in the mouth?
How are intraoral film packets packaged?
in light tight packet
Are intraoral film packets moisture resistant?
yes because it is used in the mouth
What side of the film goes towards the tube?
white side of the film
What is the dimple on the film used for?
so we know which side is which
What two views are used for dental xrays?
- parallel technique
- bisecting angle technique
How do we place the film inside the teeth.
parallel to the teeth
What is essential to obtain a clear image?
make sure neither the patient or the x-ray tube are moving or vibrating...immobilization is essential.
For the parallel technique, position the tube so the beam hits the film at a _____ angle.
Which teeth can we use the parallel technique for?
mandibular premolars and molars only
Will the parallel technique work for any teeth in the maxilla?
Which teeth do we use the bisecting angle technique for?
- maxillary premolars and molars
How do we take a x-ray using the bisecting angle technique?
instead of aiming the central beam perpendiculart o the film as in the parallel technique, the central beam is aimed perpendicular to the line bisecting the angle created between the line of the tooth and the line of the film
The beam is directed at _____ degrees to the bisecting angle.
How do we position the animal in order to radiograph maxillary canines and incisors?
in sternal recumbency and place pads or towels below the head to keep the palate parallel to the table
How do we position the animal in order to take radiographs of the rostral manibular teeth?
What should we do when taking films of the upper canines so we avoid superimposing the incisors onto the apex of the canines?
angle slightly out
How do we radiograph the maxillary premolar (carnassial)?
- position the dog in sternal recumbency and place pads or towels below the head to keep the head stable - make head parallel to table
- place the film in the mouth under the arnassial so that all of the target tooth will show in the film
- hold the film flat with props or swabs
- calculate your angles and direct the beam over the medial canthus of the eye onto the target tooth. this should be at approximately 45 degrees to the film
Do we need to take multiple views of multi-rooted teeth? Why?
- to limit the effects of superimposition of roots - either by the adjacent teeth or by another root of the same tooth
What is the tube shift technique used for?
- to isolate roots of molars
- to isolate or confirm a lesion such as periapical lucency
How do we take radiographs of teeth with roots directly behind each other?
use the SLOB technique
What is the SLOB technique?
tube shift that is used to isolate and identify each root
What does SLOB stand for?
Same Lingual Opposite Buccal
Slight rotral oblique rotation of the tube will allow visualization of the _____.
third root of the carnassial tooth
What part of the anatomy of a cats face makes them different than dogs? Why is this a problem with dental radiographs?
- cats have a more broad zygomatic arch
- the zygomatic arch will be superimposed over the tooth if you shoot it the same way as you do a dog's lateral maxilla so we need to drop the angle of the x-ray beam 30 degrees
What is elongation and how does this occur?
- makes the teeth appear longer than they really are
- occurs when the x-ray beam is not positioned correctly
How does foreshadowing occur?
when the angle of the beam is too low, the image of the tooth will be much shorter than the tooth really is
What are three ways we can process dental radiograph film?
- auto processor
- darkroom developing using rapid processing chemicals
- chairside darkroom
Which way to process dental radiographs is the easiest?
What do we use for hand processing dental radiographs?
dip tanks that can be made out of jars
How long do we dip the films?
check the label but most are...30 seconds in developer, 15 second rinse in water, 30 - 60 seconds in fixer (can read at this point but must continue to fix for 30 minutes after)
What is the film positioned between inside the film packet?
an inner lining of 2 sheets of black paper and a sheet of lead foil locked on the back of the packet
What do we need to do with the films after processing?
- rinse in circulating water for 20 - 30 minutes to rinse away all the chemical residue
- dry thoroughly
- makes copies (for digital photos)
How do we hold the film when we are reading it?
- hold film with dimple facing you
- arrange films on viewer with upper teeth pointing down, lower teeth pointing up, right is to your left, left is to your right as if you were looking at the patient face to face
What questions do we need to ask ourselves when evaluating a film?
- is image too light or dark?
- check the contrast
- has it been processed properly?
- is the image distorted or superimposed?
What do we need to check each tooth for on the dental radiograph?
- changes in contour and or density
- changes in the bone level around roots, particularly around the furcation and interproximal
- changes int he pulp chamber or periodontal space
- changes in the bone density around the root and the integrity of the lamina dura (should appear as a white line next to the dark line of the periodontal ligament)
How do we exam the jaw for lesions?
- site: location, extent, solitary, multi-focal or generalized
- size and shape: measure and describe from multiple views
- symmetry: compare with contralateral side. bilateral symmetry suggest normal
- border: sclerosis, resorption, lack of continuity
- contents: lucent or opaque, homongenous or varying density
- associationw ith other structures: displaced teeth or resorption
How do we mount dental radiographs?
- dimple out
- maxillary crowns down
- mandibular crowns up
What information needs to be included on the mount after we mount the radiographs?
- patient/client ID
- date of films
What does CEJ stand for?
cemento enamel junction
What is the alveolar crest?
ridge of bone between teeth or between roots of a tooth