Early enamel lesions in the occlusal plane are often seen and treated. One of the most common treatment interventions in early lesions whereby the caries has not yet attacked the dentine (remaining only in enamel) is to fissure seal these lesions which tends to slow down or stop the progression of decay within a tooth. Interproximal (IP) caries, are small cavities that form in the spaces between teeth. These spaces can be difficult to clean with a toothbrush and are therefore more prone to developing caries.
Icon is a minimally invasive procedure that is used to treat small IP caries in their early stages (E1 and E2 being the most predictable to treat whereas D1-D3 may require mechanical caries removal – see image 1 and 2) and can be applied for lesions with an intact surface layer and without any cavitation. The procedure involves applying a special resin to the affected area, which infiltrates the enamel and seals the lesion, preventing further damage.
Fig.1
Diagrammatic stages of interproximal caries.
E1: outer half of enamel
E2: inner half of enamel
Fig.2
Diagrammatic stages of interproximal caries.
D1: Outer third of dentine
D2: Second third of dentine
D3: deeper third of dentine
Fig.3
When considering whether to use resin infiltration (Icon) or a direct composite restoration to treat caries, a few factors should be taken into account. In addition to the extent and progression of the carious process, it is important to consider whether the caries is cavitated or not. In cases of cavitated lesions, resin infiltration is not recommended, and a conventional composite restoration should be performed instead. In practice, however, it can be difficult to make a definite treatment decision due to the limitations in the diagnostic techniques.
While bitewing X-rays can provide valuable information about the depth of the lesion, they do not reveal whether a lesion is cavitated or not. Only direct visual examination can determine this. This image (Fig 3) shows an example of how a lesion on a tooth can be diagnosed through direct examination. A small E1 lesion can be seen interproximally (circled).
Fig.4
Below is a workflow summary of Icon proximal:
Step 1. Diagnosis of interproximal caries: radiographic E1 and E2 lesions (arrows).
Fig.5
Step 2. Separation of the teeth can be carried out using a number of methods:
I. Orthodontic rubber bands: where possible, it is recommended to place the rubber bands 1 to 5 days before treatment to allow separation to occur.
Fig.6
II. Using the Icon wedges supplied in the Icon proximal package.
Fig.7
III. The use of an Ivory separator. This is placed between the teeth and the screw turned to slowly separate the teeth in question.
Fig.8
Step 3. The affected areas are cleaned using Aquacare by Velopex or equivalent to remove any visible plaque or tartar.
Fig.9
Step 4. With the teeth clean and separated we can start the Icon treatment.
Fig.10
Step 5. Icon Etch, a 15% hydrochloric acid gel, is applied using the proximal tip.
The etching process takes 120 seconds, after which the gel is thoroughly rinsed off for 30-60 seconds.
Fig.11
Step 6. Once the gel is rinsed off, carefully dry the area. Icon Dry, a solution of ethanol, can then be used to thoroughly dehydrate the treated area. Simply apply Icon Dry using the application tip provided for 30 seconds and then allow the area to air dry. The lesion should be desiccated.
Step 7. Steps 5 and 6 may need to be repeated up to three times until the lesion has desiccated and appears to disappear when the dry (ethanol) agent is applied.
This will provide the best results and penetration of the resin.
Fig.12
Step 8. Apply the resin infiltrant using a new proximal tip. Leave this on the tooth for 3 minutes. Slightly moving the applicator will enhance resin penetration.
Fig.13
Step 9. Once the time has passed, air dry, and use floss to remove any excess and light cure for 40 seconds on each side.
Fig.14
Step 10. Repeat steps 8 and 9, attach a new proximal tip to the resin infiltrant syringe and apply it to the desired site. Allow the material to penetrate for one minute, then remove the application tip from the site. Use dental floss to remove any excess material and cure for another 40 seconds per side.
Fig.15
Step 11. As a last step, use a composite finishing strip to remove any excess and smooth the areas over. Figure showing the completed Icon treatment of the lower right premolars. Steps 1-11 should be repeated for all the necessary lesions as per treatment plan. We can see that the teeth have closed back following the removal of the wedge.
The patient should be advised to continue to brush and floss regularly to prevent future caries from forming. It is also recommended that the patient return for periodic check-ups to monitor the treated area with bite wing radiographs and clinical examination.
Conclusions
Icon is a fantastic conservative treatment modality. In most cases where Icon is used there is no need for anesthetic, drilling, or tooth damage. It is important to follow the instructions and utilise the icon-dry solution to preview the results before placing the resin infiltrant. In most cases Icon can be used as an alternative to cavity preparation, prolonging the time before a more invasive treatment is needed, or eliminating the need of such intervention.
Bibliography
1. Shaalan O. Bleaching, microabrasion and composite restoration. 2019 styleitaliano.org
2. Manauta J, Salat A. Layers, An atlas of composite resin stratification. Chapter 5. Quintessence Books, 2012.
3. Attal J P, Atlan A, Denis M, Vennat E, Tirlet G . White spots on enamel: treatment protocol by superficial or deep infiltration (part 2). Int Orthod 2014; 12: 1–31.
4. Paris S, Schwendicke F, Keltsch J, Dorfer C, Meyer-Lueckel H . Masking of white spot lesions by resin infiltration in vitro. J Dent 2013; 41: 28–34.
