Posterior resin infiltration and direct vision
The infiltration technique we’ve been talking about might actually be a great way to stop interproximal incipient caries in a non invasive way. Posterior resin infiltration requires direct vision of the proximal lesions of the enamel. These kind of lesions before cavitation, the initiation of the caries process, is characterized by a subsurface white spot formation, with a overlying almost intact surface.
Once a tooth is cavitated because of a caries, the lesion tends to progress. (5)(6) So ideally before having a cavitated lesion some kind of intervention should be done: to invert the process of demineralization to a remineralization, or, at least, to stop the demineralization process.
Remineralization of white spot lesions with an intact surface is possible. The lesion can be stopped and we can rely on calcium and phosphate ions. The use of topical fluorides to enhance remineralization of demineralized proximal enamel has been advocated (7). For example one of the protocols that demonstrated some benefits is the application of fluoride varnish every third months. It significantly reduces the progression of proximal caries lesions in premolars and molars. The most obvious reduction of caries progression is observed among children with moderate caries risk, while children with high caries activity (more than 9 new proximal lesions) do not benefit from proximal caries reduction. (8)
Cavity preparation is nowadays considered destructive and outmoded in incipient proximal lesions because another less invasive techniques are possible.
A considerable number of professionals still tend to practice invasive techniques with lesions confined to enamel ranged from 19% to Norway (Tveit et al) to nearly 50% in Mexico and Brazil (Traebert et al).
The resin infiltration technique in interproximal caries lesions is a less invasive technique compared to a cavity preparation and fits in the concept of minimal intervention dentistry.
THE INFILTRATION TECHNIQUE
The infiltration technique should be an alternative to cavity preparation, thus at least postponing (if not avoiding) sacrifice of sound structures.
Resin Infiltration technique is contraindicated in cavitated lesions but instead is a treatment option in non cavitated incipient (interproximal) enamel lesions.
The problem in posterior teeth is the bitewing radiograph does not give any direct information on the surface integrity of proximal lesions.
Clinical studies (Bille et al) found comparably few cavitations in R3 lesions (radiolucency reaching the outer dentin on bitewings) lesions (22% to 52%), while several laboratory studies confirmed a considerably earlier cavitation with breaking of surfaces in up to 100% of R3 lesions (Kielbassa et al).
The best condition should be to have direct vision to the tooth to be able to verify the presence/absence of cavitation and to be able to check the activity/inactivity of the lesion.
In this article we explain a tip that we use in our daily practice to achieve the direct vision to the lesions in the case of interproximal lesions.
Usually we use the 27N clamp for molars.
Resin infiltrant was applied. We let it set for 2 minutes and then we light cure.
The physical barrier is expected to give a protective function against exposure of acids from bacterial origin, and cutting off possibly remaining bacteria (within an advanced lesion) from a nutritional supply of fermentable carbohydrates. (Gomez et al)
Check ups of the lesions should be performed. We expect reduced or inhibited caries progression.
Resin infiltration technique with Icon is a treatment option in incipient interproximal enamel caries. One limitation of the resin infiltration concept is that in interproximal posterior enamel lesions with a bitewing radiography is not possible to evaluate the presence of a cavitation. In cavitated lesions Icon is contraindicated. Neither another method like photoillumination lets you determine the integrity of the outer part of the lesion. Thats why in our protocol in interproximal caries with a contact point we open the space with an orthodontic elastic 5 days before the appointment. With the direct view we reevaluate the lesion and take the decision how to proceed to treat the caries lesion.
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