Toothbrush bristles cannot access the pit and fissure system because the dimensions
of the fissures are too small. As a result micro-organisms remain undisturbed within
the fissure system. The tooth is most susceptible to plaque stagnation during eruption,
that is, a period of between 12 and 18 months. During this time, children need extra
parental help in maintaining their oral hygiene. Lesion formation takes place in the
plaque stagnation area at the entrance to the fissure and commences with subsurface
demineralization. Demineralized enamel is more porous than sound enamel. The more
demineralized and porous the affected enamel, the more it shows up both clinically
and on radiographs.
Key Point
To detect the earliest white spots the tooth must be dried to render them more
obvious.
Once the initial lesion has developed, caries may spread laterally such that a small
surface lesion may hide a much greater area of destruction below the surface (415HFigs.
9.4 and 416H9.5).
Remineralization of occlusal lesions is much more difficult to achieve. Fissure
sealing, 6 monthly 2.26% fluoride varnish application with oral hygiene instruction,
and a weekly 0.2% sodium fluoride rinse, have all been found to help stabilize the
disease and retard the progress of occlusal caries, but the fissure sealing group
exhibited the best effectiveness. Many studies have shown that generally as the caries
rates decline, the proportion of caries that affects pits and fissures of molar teeth
increases, and also that the caries appears to be concentrated in a smaller cohort of
children⎯most of the decay occurs in 25% of the child population. This predilection
has meant that correct use of fissure sealants should have a maximal effect.
There is no dispute that when correctly applied and monitored, fissure sealants are
highly effective at preventing dental caries in pits and fissures, but interpretation of
the correct application and monitoring requires scrutiny.
Key Point
Fissure sealants reduce caries incidence but must be carefully monitored and
maintained.