Caries Infiltration for Minimally Invasive Dentistry
New product and technique offers a new alternative for early-stage lesions.
Over the past 2 decades, dentistry has moved increasingly from the traditional “extension for prevention” model of dentistry toward a less invasive form of treatment. Where tooth structure was once sacrificed as a primary means of treatment, the profession has adopted a model of minimally invasive dentistry. Caries infiltration is just such a treatment option recently introduced by DMG America (http://www.dmg-america.com) in the form of Icon®, which provides for micro-invasive treatment of early caries lesions without the need for anesthesia or drilling. The treatment is based on the premise that the establishment of a diffusion barrier within the porous incipient lesion will strengthen, stabilize, and arrest the progression of the lesion while returning the whitish appearance back to the look of sound enamel. 1,2
This unique treatment method provides an additional treatment option between remineralization of carious lesions and their treatment through restorative techniques.3 This “bridge” treatment provides a newly available opportunity to preserve healthy tooth structure that would otherwise be lost during restoration; most commonly Class II restorations. Resin infiltration provides for the specific treatment of early carious lesions without the need to prepare access preparations, thus protecting and fully preserving the hard tissue surrounding the lesion. The treatment presents many advantages, especially in pediatric dentistry. It is painless; therefore, it is well accepted by a majority of patients in virtually all situations where it is applicable.
An 18-year-old girl presented with a number of post-orthodontic white spots (Figure 1). She was extremely self-conscious of the defects and was seeking a solution to the problem. White-spot lesions of this sort are caused by long-term exposure to plaque and the cariogenic bacteria present in biofilm. Within the demineralized lesions there is a pore system, and contained within these is an air/liquid mixture. The white spot is caused by the difference in the refractive index of air and healthy tooth structure. An example of this phenomenon is white foam on a glass of beer.
The patient chose to have an infiltration of the lesions, in part because the procedure would be performed in a single appointment. The several lesions that would be treated would require an appointment of approximately 45 minutes.
The treatment aim was to fill enamel lesions with a light-curing resin. Fissure sealing has been proven to be an effective method for protecting occlusal tooth surfaces from developing carious lesions.4 Although fissure sealing was initially intended as a purely preventative measure, current studies show that occlusal surfaces already affected by caries can be effectively protected from progression.5 Long-term clinical studies on fissure sealing suggest that remaining bacteria in a lesion do not constitute a risk factor for a progression of the infiltrated lesion.6 The foundation for the new approach to treat early caries was established in the 1970s. The research group led by Dr. Buonocore conducted first experiments in penetrating carious lesions with low-viscosity resins.7 The lesion “body” is the most extensively demineralized zone of the several zones of the lesion and lies below a layer of healthy enamel, the remineralized surface layer.8 This remineralized enamel surface layer would obstruct the penetration of the infiltrant and must, therefore, be systematically removed. Consequently, within minutes, the infiltrant will penetrate the caries to a depth of several hundred microns.9 Because of this earlier work, research has been able to demonstrate the clinical efficacy with regard to preventing a further caries progression with the application of this micro-invasive therapy. The infiltration of proximal and smooth surface lesions with low-viscosity light-curing composites thus complements the current trend toward increasingly minimally invasive treatment.
After prophylaxis of the tooth or teeth to be treated and adjacent teeth, they should be rinsed clean with water. A liquid dam should be placed to protect the gingiva during etching and to have a dry working area. As previously noted, access to the lesion body is crucial to the success of the technique, and so the author performed two separate etching steps. It is through the removal of the remineralized enamel layer that covers the lesions that infiltration is possible.10
The next step is to attach the Smooth Surface Tip to the Icon-Etch syringe. Apply a thin layer of the 15% HCL gel (Icon-Etch) to the lesion surface by slowly turning the syringe plunger approximately twice (Figure 2). The Icon-Etch should be applied about 2 mm beyond the margins of the lesion(s) and be allowed to sit for 2 full minutes. The etchant should be rinsed away with water for at least 30 seconds (Figure 3) and dried with oil-free and water-free air.
The author recommends repeating each of these etching steps a second time for best results.
After attaching the needle tip applicator onto the Icon-Dry syringe and applying several drops of the Icon-Dry onto the lesion, allow it sit for 30 seconds then dry with oil-free air. It should be noted that during the drying step, the lesion should lose all of its whitish appearance while the Icon-Dry is present within the lesion. The appearance of a whitish appearance, or any discoloration, indicates that there is remaining enamel on the surface of the lesion that must be removed before the infiltration step (Figure 4). Should any whitish appearance be present, proceed with the etching step for a third time.
Redirect or turn off the operatory light for the application of the Infiltrant. Attach a new Smooth Surface Tip onto the Icon-Infiltrant syringe, and apply an ample amount onto the etched lesion surface and let it sit for 3 minutes11 (Figure 5). Wipe excess from the surface with a cotton roll or similar material. Remove any resin from the contacts of adjacent teeth with dental floss to prevent bonding of the contacts (Figure 6). Light-cure for 40 seconds. Attach a new Smooth Surface Tip and apply a second layer of Icon-Infiltrant and let sit for 1 minute. Remove excess material, as above, and light-cure again for 40 seconds12 (Figure 7).
Infiltration therapy provides an entirely new treatment option for incipient caries without the use of anesthesia or drilling. Infiltration is indicated for non-cavitated lesions in any-age patient. Infiltration is a simple, painless, and ultraconservative technique that allows for immediate treatment of lesions not advanced enough for restorative therapy. It has been shown to stop caries progression in lesions that are too advanced for fluoride therapy.
Until recently, dentists and hygiene professionals had only two principal options for treating incipient decay: remineralization therapies, as noted previously, or traditional restorative procedures. The white-spot lesions, which have been the subject of this discussion, are often subject to invasive procedures to meet patients’ esthetic demands. Icon caries infiltration treatment offers an innovative treatment for returning these demineralized teeth to their original healthy look.
Caries infiltration is a major breakthrough in micro-invasive dentistry that will fill, reinforce, and stabilize demineralized enamel. Caries infiltration prevents lesion progression so it has the potential to delay additional treatment of a caries site and, thus, prolong the life expectancy of that tooth.13,14 It has the potential to help patients avoid more extensive treatment and invasive restorative procedures.
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9. Meyer-Lueckel H, Paris S. Improved resin infiltration of natural caries lesions. J Dent Res. 2008;87(12):1112-1116.
10. Meyer-Lueckel H, Paris S, Kielbasa AM. Surface layer erosion of natural caries lesions with phosphoric and hydrochloric acid gels in preparation for resin infiltration. Caries Res. 2007;41(3):223-230.
11. Meyer-Lueckel H, Paris S, Mueller J, et al. Influence of the application time on the penetration of different dental adhesives and a fissure sealant into artificial subsurface lesions in bovine enamel. Dent Mater. 2006;22:22-28.
12. Paris S, Meyer-Lueckel H, Colfen H, Kielbasa AM. Penetration coefficients of commercially available and experimental composites intended to infiltrate enamel carious lesions. Dent Mater. 2007;23:742-748.
13. Paris S, Meyer-Lueckel H, Kielbasa AM. Resin infiltration of natural caries lesions. J Dent Res. 2007;86(7):662-666.
14. Meyer-Lueckel H, Paris S. Improved resin infiltration of natural caries lesions. J Dent Res. 2008;87(12):1112-1116.
About the Author
Richard Connelly, DMD