Radiographic Diagnosis of Caries Flashcards
What is caries?
It is a multifactorial disease
What causes dental caries?
Lactic acid produced by bacteria decreases the pH of the mouth leading to demineralisation of enamel leading to caries and tooth decay
What factors are essential for caries formation?
- Tooth surface
- Bacteria
- Sugar
4, Time
How can carious lesions be classified?
- By their anatomical site
- By their activity
- By their level of disease
How can carious lesions be classified according to their anatomical site?
- Pits or fissures
- Smooth surface (gather around the gingival margin)
- Enamel
- Root
- Primary (on a new sound tooth surface)
- Secondary (the nits associated with a restoration)
- Residual
How can carious lesions be classified according to their activity?
- Active caries which can be rampant (affect all teeth) , bootle or early childhood
- Arrested or inactive
How can carious lesions be classified according to their level of disease?
D1
D2
D3
D4
Describe a D1 carious lesion
White/ opaque or brown lesion but the surface is hard and the occlusal surface is hard on probing
Describe a D2 carious lesion
Theres slight loss of surface
Sticky tissues
No dentin involvement
Describe a D3 carious lesion
Dentine involvement but not pulp
Describe a D4 carious lesion
Possible or definitive plural involvement
How are D1 and D2 lesions managed?
With preventative measures
How are D3 and D4 lesions managed?
They most likely need restorative treatment
How can dental caries be detected?
- Visual inspection
- Radiography
- Temporary tooth separation
- Fibreoptic transillumination (FOTI)
- Laser fluorescence
- Electrical conductance measurements
- Research techniques – e.g. MRI
What is the gold standard for caries diagnosis?
Visual inspection
How do we diagnose caries by visual inspections ?
We dry the tooth surface and then look at every tooth surface under good light
What is the most commonly used special test for caries detection?
Radiography
How is temporary elective tooth separation used to detect caries ?
It is where you use little orthodontic bands between the teeth to open up a contact point so that you can now see if theres any caries in that gap
How is Fibre-Optic TransIllumination (FOTI) used to detect caries ?
This is a process where you shine a bright light between the teeth
If you have a sound tooth surface light will spread and there’ll be a smooth colour
Where’ve their is caries there will be a distribution in the light
How is Fluorescence used to detect caries ?
You shine a light of a certain wavelength through a tooth and as the light passes through the substance you get some scattering and some absorption
As you get scattering the wavelength and colour of the light changes
Caries often fluoresces the most in comparison to dentine and enamel
Give the different types of radiographs we can take to diagnose caries
- Bitewings
- Periapicals
- Oblique lateral
- Panoramic
What is the gold standard when using radiographs for caries detection
Use bitewings
Why are bitewings the gold stander for radiographic caries detection
As you can see the crowns of all of the posterior teeth including the occlusal and inter proximal surfaces
How do you carry out a bitewing?
You place a single filler in the holder
Then place the holder in the patients mouth
The patient bites on the bite block and a radiographic image is produces
Which area of the mouth can you see when taking a bitewing?
You can see the from the mesial contact point of the first premolar to the most distal contact point in the mouth (2nd or 3rd molar)
What are some of the benefits of taking bitewings?
- They provide maximum coverage of risk areas for the lowest dosage
- Theres no or minimal overlap of enamel
- It is a reproducible technique
How much enamel overlap is acceptable on a radiograph?
Up to half thickness of enamel is allowed
What are the positive and negative of taking periapical radiographs
They have a similar resolution to bitewings but few crowns are shown on individual film for the sam e dose
What are some of the disadvantages of taking oblique lateral radiographs?
It is an extra oral image that has a lower resolution than bitewings
When might taking an oblique lateral radiographs be useful?
May be useful for caries diagnosis in young children
What are the disadvantages of panoramic radiographs
Extraoral film means lower resolution
Magnified image
Has artefacts
Not indicated fro caries diagnosis
What is available o some newer panoramic units?
Extra oral bitewings
What are some of the advantages of extra oral bitewings?
- More comfortable for the patient
- Better interracial separation between contacts than a panoramic
- 50% dose reduction than normal panoramic
What are some of the disadvantages of extra oral bitewings?
Compared to intramural bitewings extra oral bitewings have a :
- Higher dose
- Lower resolution
- increased artefacts
- Less reproducible
What is the rationale for radiographs?
- They show mineral loss through decreased density of dental hard tissues e
- Reveals lesions otherwise undetectable by clinical exam
When can caries be seen on a radiograph
When there’s 40% mineral loss
What does caries cause?
- Demineralisation of inorganic portion
2. Destruction of organic portion
What is caries seen as on a radiographs?
A radiolucent area
Why is caries seen as a radiolucent spot on a radiographs
- Caries causes Demineralisation of enamel and/or dentine
- This leads to decrease in density
- This results in a decrease in attenuation of X-ray photons
- So the area becomes radiolucent (darker) on a radiograph
What causes occlusal caries
Food debris and bacteria in pits and fissures causing decalcification of enamel
How does occlusal caries look on a radiograph when it reaches dentine?
It appears to spread laterally and is seen as a triangular shape on a radiograph
Where is Approximal caries found?
On the medial and distal surfaces of a tooth
Where do approximal caries spread?
Spreads lateral into dentine
Where can buccal and lingual caries arise?
Can arise in pits and tissues
Describe how buccal and lingual caries may be seen on a radiograph
Small lesions are usually rounded becoming more elliptic or semilunar as they get bigger
How is root surface caries detected?
Usually detected clinically
What is involved in a root surface lesion?
Lesion involves cementum and dentine and are associated with gingival recession
When looking for root surface caries on a radiograph what should we beware of?
Beware of cervical burnout artefacts
Where does current caries occur?
Occursadjacenttoan existing restoration
How do we report caries?
We assess each tooth individually
Start in the UR quadrant the UL-> LL-> LR
What do we assess when reporting caries
- Full crowns, enamel and dentine density
- Cervical margins
- Existing restorations
- Pulp chamber
When do a radiograph report what do we do?
- Determine the quality grade of the image
- State which teeth you can see
- List your findings
What are some of the problems associated with radiographs?
- The use of ionising radiation
- Technique errors such as geometry, faulty processing
- Overlapping contact points obscuring early lesions
- Due to projection a superficial lesion can be projected deeper e.g. an enamel lesion can appear to be into dentine
- They are a 2D representation of a 3D subject
- Very early lesions not evident at all
- Lesions usually larger clinically than radiographically
- Cannot establish bucco- lingual depth or localise to buccal or lingual surface
Name some artefacts on a radiograph that can mimic caries
- Cervical burn out artefact
- Mach effect artefact
- Corrosion products
What causes cervical burnout artefact?
Due to x rays overpenetrating for burning out the thinner tooth edge
Describe how cervical burner may look on a radiograph
- Cervical root edge will be intact albeit dark
2. Usually inner edge is more diffuse and rounded than caries
What is the mach band effect?
It is a visual illusion that shows that when dark dentine meets light enamel, the dark shade appears even darker and light shade lighter making the darker areas look like caries
What causes corrosion products on a radiograph?
- Radiolucency deep to amalgam restoration can mimic caries
2. Deposits of heavy metal ions e.g. tin, zinc in softened dentine.
What can cervical burnout artefact look like on a radiograph?
Root surface caries
When should we take radiographs for high risk patients?
Posterior bitewings should be taken at 6 month intervals until no new or active lesions can be seen or patient changes into a different risk factor
When should we take radiographs for moderate risk patients?
Take posterior bitewings annually
unless risk status alters
When should we take radiographs for low risk patients?
Take posterior bitewings at 12-18 months in primary dentition
Take x ray sat 2 year intervals in permanent dentition
When should bite wings be considered for a child?
- 5 years
- 8-9 years
- 12-14 years
