July 1st, 2009 by admin

Caries on free smooth
enamel
surfaces can be diagnosed with sharp eyes at
the stage of the white or brown spot lesion (see Figures 1.4 and 2.7) before
cavitation has occurred provided the teeth are clean, dry, and well lit. Drying
is very important because, as explained on page 29, it gives the clinician an
idea of the porosity and depth of the lesion. Active lesions tend to be plaque
covered, close to the gingival margin and may have a matt appearance
indicative of surface loss of tissue (see Figure 1.4 on page 6). These lesions
may feel rough if the tip of a sharp probe is gently drawn across them (be
gentle—the probe is an explorer, not a bayonet!). Arrested lesions, on the
other hand, may have been abandoned by the gingival margin and may have
a plaque free, shiny, lustrous surface (see Figure 2.2 on page 23). Sometimes
these lesions are brown because the porosities have absorbed exogenous
stain from the mouth.
Root surface
caries, in its early stages, appears as one or more small, well
defined, discoloured areas located in an area of plaque stagnation close to the
gingival margin (Figure 3.5). Lesions may vary in colour from yellowish or
light brown, through mid- brown to almost black. Active lesions are plaque
covered, soft or leathery in consistency and may be cavitated. Arrested
lesions are hard and are often located in a plaque free area coronal to the
gingival margin (Figure 3.6). Arrested lesions may be cavitated.
Although lesion consistency is important in diagnosing activity, great
care should be taken when using a sharp instrument on these surfaces.
Arrested root caries in a plaque-free area, coronal to the gingival
margin.
sharp probe could cause a small hole in which plaque will subsequently
collect, possibly protected from the toothbrush bristle. It may be safer to
test the consistency of the lesion by gentle use of a periodontal probe or
the back of an excavator. It should be noted that colour is not a good indica-
tor of lesion activity. It seems likely that the colour of the lesion is due to
exogenous staining from such items as tea, coffee, red wine, or chlorhexidine
mouthwashes. This colour may re ect the use of these liquids rather than
lesion activity.
Root surface lesions tend to spread laterally and coalesce with minor
neighbouring lesions and may thus eventually encircle the tooth. Com-
monly, the lesions extend only 0.25–1 mm in depth. They do not always
spread apically as the gingival margin recedes, but new lesions may develop
later at the level of the new gingival margin. This may occur irrespective
of an arrested lesion being located more coronally at the cement-enamel
junction of the tooth.
In order to carry out an accurate visual examination it is very important the
surface is plaque free. Ideally the plaque should be disclosed and brushed
away. Visual examination and examination of bitewing radiographs are both
important. The active, uncavitated lesion is white, often with a matt surface.
The corresponding inactive lesion may be brown. The enamel lesions are not
visible on a bitewing radiograph. The enamel lesion that is only visible on a
dry tooth surface is in the outer enamel. The lesion visible on a wet surface
 White and brown spot lesions on the occlusal surface of a molar.
There was no lesion in dentine on a bitewing radiograph. (b) A microcavity, looking
like a slightly enlarged, brown fissure on a first lower molar (arrow). (c) A bitewing
radiograph of the tooth seen in 3.7b shows occlusal caries in dentine (arrow).
(d) The soft demineralized dentine has now been removed from the tooth seen in
3.7b–c. (e) An occlusal lesion in this molar is seen as a greyish discolouration of the
enamel. This lesion was visible in dentine on a bitewing radiograph. (f) The lesion
seen in 3.7e has now been accessed with an air rotor. Soft, demineralized dentine is
present.
Cavitated occlusal lesion is a first molar. The more mesial is a
microcavity but the cavity on the distal aspect exposes dentine. The lesion was
visible on a bitewing radiograph. (h) The lesion seen in 3.7g has now been
accessed with an air rotor. This is a large lesion with much soft, demineralized
dentine.
is all the way through enamel and may be into dentine. Cavitated lesions
may present as microcavities with or without a greyish discoloration of the
enamel. The microcavity is easily missed on visual examination. Careful
examination of bitewing radiographs is important and serves as a useful
safety net to avoid missing microcavities. A lesion that has been missed on
visual examination but found on radiograph (Figure 3.4) has been called
hidden caries
. More advanced lesions may present as cavities exposing
dentine. Cavitated lesions are usually visible in dentine on a bitewing radio-
graph. Cavitated occlusal lesions, whether microcavities or cavities down to
dentine, are usually active because the patient cannot clean plaque out of
the cavity
Laser  uorescence method
4
In recent years a laser  uorescence machine has become commercially
available (DIAGNOdent, KaVo, Biberach, Germany) to aid the detection of
occlusal caries. The machine emits light with a wavelength of 655 nm
and this is transported through a fibre bundle to the tip of a handpiece
(Figure 3.8). The tip is placed against the tooth surface and rotated. The laser
light will penetrate the tooth. Different fibres in the tip receive the re ected
light and  uorescence from the lesion, thought to be produced from bacterial
porphyrins. The received light is measured and its intensity is an indication of
the size and depth of the carious lesion. The machine is not detecting mineral
loss
per se
. The reproducibility of the machine has been shown to be very
clean and dry.
good but it can be confused by staining and calculus, giving high readings
when active caries is not present. Whether this machine will become a
helpful tool in the diagnosis of occlusal caries when used by general practi-
tioners has yet to be established. In the meantime, its readings should be
interpreted with caution and combined with a conventional clinical-visual
and radiographic examination.