Caries Diagnosis

• The caries progress is a continuum - very earliest loss of mineral to total breakdown. It's also a dynamic process, always switching between remineralisation and demineralisation. Therefore diagnosing caries can be difficult because it can present in different ways and at different stages of the disease process.
• Visible part of caries (above the waterline) is a v small part of all the caries that's actually there. Open and closed = cavitated and non-cavitated. When doing examinations now we aim to detect anything from the top 4 layers.

  
• • Initial stage = enamel caries
  • Moderate stage = cavitated, but still in enamel OR non-cavitated dentine caries
  • Extensive stage = open cavity into the dentine

  All 3 carious stages (initial, moderate and extensive) are broken down into 2 different levels within those stages.

  
• Diagnosis of caries - combination of staging, activity levels of the lesion and patient risk factors. Primary risk factors:

  • Saliva
  • Diet
  • Fluoride
  • Oral biofilm
  • Modifying factors
• Primary risk factors for caries - saliva:

  • Ability of minor salivary glands to produce saliva
  • Consistency of unstimulated (resting) saliva
  • pH of unstimulated saliva
  • Stimulated salivary flow rate
  • Buffering capacity of stimulated saliva
• Primary risk factors for caries - diet:

  • Number of sugar exposures per day
  • Number of acid exposures per day
• Primary risk factors for caries - fluoride:

  • Past exposure
  • Current exposure
• Primary risk factors for caries - oral biofilm:

  • Differential staining
  • Composition
  • Activity
• Primary risk factors for caries - modifying factors:

  • Past and current dental status
  • Past and current medical status
  • Compliance with oral hygiene and dietary advice
  • Lifestyle
  • Socioeconomic status
• Diagnosis of caries is about looking at how active the caries is; we could have a big cavity that has arrested caries (not very concerning; not progression) or a big cavity of active caries, which would be of much more concern.

  
• Caries detection can lead on to diagnosis when we've got a bit more information. And the diagnosis is important because that is going to influence out treatment decision (may be able to reverse the caries if it is at an early level - or may have to restore if it's more extensive).

  So getting the diagnosis right is really important to ensure that you get the right outcome for the patient.

  
• Why it's important to be able to detect and diagnose caries:

  • Very prevalent disease - great burden
  • Cause infection (medical impact)
  • Cause pain (psychological impact)
  • Be disfiguring (social impact)
• Detection and diagnosis of caries is important in:

  • Assess prognosis
  • Targeting prevention of the right teeth for the right people
  • Treatment decision
  • Informing the pt - motivator for behaviour change
  • Advising health service planners (where caries is = where dentists are needed)
• Differential diagnosis = diagnosis of a condition whose signs +/or symptoms are shared by various other conditions

  • Fluorosis; would expect caries where plaque accumulates - therefore would be difficult to get plaque all the way up those smooth surfaces in that speckled pattern
  • Caries; there may have been a tooth in front of that tooth & classic place for plaque to accumulate (just below contact point) and caries to start - also seems to have a white, chalky appearance

  
• • C = carious around gingival margin - classic place to get decalcification - early enamel caries
  • D = hypoplastic tooth; v strange place to get caries (may get caries in the defect, but wouldn't typically appear on that smooth surface) - it's just a little hole where enamel hasn't formed properly, giving a brown appearance
  • E = hypoplastic (why it looks yellow) and has a large composite/GIC restoration in it - doesn't visibly appear to have caries
  • F = amalgam restoration and caries around the buccal margin (white line where gingival margin may have once been; gingivae could have receded)

  
• • G = Amelogenesis Imperfecta (a genetic defect of enamel formation) - pitted appearance - not typical place for caries (smooth surface)
  • H = carious - shadowing around the central fossa indicates there's caries underneath
  • I = hypoplastic - not a usual pattern for caries

  
• • J = just arrested caries
  • K = staining; no sign of any shadowing around that - would probably depend on the patient's history though; if patient has high risk of caries, it could be a sign of enamel caries

  
• Differential diagnosis of dental caries:

  • Clinical
  • Normal anatomical pits
  • Developmental defects: hypoplasia, opacities
  • Extrinsic staining
  • Radiographic
  • The above
  • Radiolucent restorations
  • Tooth loss due to wear, fracture
  • Technique faults

  
• Direct visual diagnosis of caries:

  • Sharp eyes (magnification can help too)
  • Teeth clean, dry and well-lit
  • A = wet
  • B = dry - can pick up the areas of demineralisation much more clearly
  • Active vs arrested lesions
  • Colour

  
• Use of an orthodontic separator to diagnose approximal caries visually. Pushes teeth apart slightly so that you can get a bit of a better look at the interproximal walls.

  
• Fibre-optic transillumination:

  • Shine light through the tooth - light goes down fibre optic cable and through tooth
  • Tooth looks a bit white and chalky interproximally - shine a light through it to reveal definite dark spot where suspected lesion was
• Shining fibre optic cable on the tooth isn't as good as shining it through the tooth. A carious lesion has a lowered index of light transmission than sound enamel.

  
• QLF (quantative light-induced fluorescence) - shines light on tooth and sees how much the tooth fluoresces (shines the light back) - demineralised enamel reflects the light back less than sound enamel.

  
• Digital radiography:

  • Digital image enhancement
  • Digital subtraction radiography
  • When you put an old radiograph on top of a new one so that you can look at where the differences lie
  • Tuned aperture computed tomography (TACT) and limited cone beam computed tomography - higher radiographic dose so not typically used for caries diagnosis
• DIAGNOdent (Quantitative Laser Fluorescence) = tip of the handpiece shines a laser at the tooth and then measures how much of the laser comes back - useful for accessible areas of the tooth, like cases of occlusal caries.

  
• Electrical Conductance Measurement:

  • Enamel is a poor electrical conductor because of its small pores - as soon as it demineralises it becomes a better conductor
  • Can be used to measure how well the tooth conducts or how well the tooth impedes electricity
  • Measures whole tooth - gives you more of an idea of demineralisation besides just the occlusal surface

  
• Bioluminescence:

  • Can create photo-protein which emits light when binds with specific ion
  • Created one to work with calcium
  • Device squirts photo-protein onto tooth
  • Camera picks up flash of light as it binds calcium
  • If the tooth is demineralised and calcium is being released from the surface, more light will be flashed back than if the tooth was sound because the calcium would be bound to the tooth

  
• Caries diagnosis depends, to some extent, on the type of surface:

  • Free smooth surface (buccal/lingual)
  • Pit and fissure
  • Approximal
  • Root surface
• Caries diagnosis - free smooth surface:

  • Visual (can see it easily with own eyes)
  • FOTI (fibre-optic transillumination) and Quantitative Light Fluorescence (QFT) might be kind of helpful but not as much as visual detection
  • All other methods, like laser fluorescence may help a bit but wouldn't add a huge amount
• Caries diagnosis - pits and fissures:

  • Visual (limited)
  • Radiological examination - bitewings - very helpful here
  • Electrical resistance, laser fluorescence and light-induced fluorescence measurements - may help to some degree as well
• Approximal caries:

  • Only visible clinically at a relatively late stage when lesion progressed into dentine. Tooth separation using orthodontic separators.
  • Extra help is most needed in these cases
  • Bitewing radiographs are what we mainly rely on in these cases
  • Transmitted light can help in diagnosis - FOTI (Fibre Optic Transillumination)
  • Electrical resistance, laser fluorescence and light-induced fluorescence measurements