Erosion Infiltration Technique': A Novel Alternative for Masking Enamel White Spot Lesion.

Enamel White spot lesions are early signs of demineralization under the intact enamel, which may or may not lead to the development of caries. An inactive white spot lesion might act as an arrested dental caries and impair the esthetic appearance by displaying a milky white color from its interior opacity. The first choice of treatment is remineralization with various remineralizing agents such as fluoride and ACP-CCP. Caries infiltration is a less invasive and effective method for arresting the white spot lesions. It also improves the esthetics by masking the chalky white appearance by the process of optical adaptation to the adjacent healthy enamel. This is achieved by the hydrophobic resin, which has a similar refractive index to that of the healthy enamel.

INTRODUCTION

Enamel White spot lesions are early signs of demineralization under the intact enamel, which may or may not lead to the development of caries. An inactive white spot lesion might act as arrested dental caries and impair the esthetic appearance by displaying a milky white color from its interior opacity. Several conditions such as fluorosis, trauma, initial caries, medicine intake during enamel mineralization, molar incisor hypomineralization, premature birth can exhibit enamel white spot lesions.[1] Management of this type white spot lesion is generally by means of topical application of Fluoride therapy, Casein-Phospho Peptide-Amorphous Calcium Phosphate pastes, Novamin (calcium sodium phosphosilicate).[2] All these treatment modalities end up in surface remineralization, but the subsurface is still porous.

To overcome the drawback of retaining a porous subsurface caries, resin infiltration seems to be a promising and less invasive treatment modality. In this method, the subsurface porosities are occluded by a clear hydrophobic resin applied on the surface of the conditioned lesion.[3] As a positive side effect, the white spot is also masked because the refractive index (RI) of the lesion becomes similar to the sound enamel.

CASE REPORTS

Case report 1

A 24-year-old male patient reported to our department with a chief complaint of white patches in the upper front tooth. On examination, an isolated moderate size enamel white spot lesion was found in the right upper maxillary central incisor. Informed consent was obtained from the patient and treatment plan was established as Caries Infiltration with ICON (DMG, Germany).

After Rubber dam application, the teeth was cleaned using prophylaxis paste, the surface of the lesion is conditioned with 15% hydrochloric acid gel (ICON ETCH, composed of 15% hydrochloric acid, DMG) in a circular motion with a contact time of 2 min, the etching gel is then rinsed away (30 s) using water spray. To completely dry the body of the lesion, ethanol (ICON DRY, DMG, Germany) is applied. A resin infiltrant (ICON, DMG) is applied on the lesion surface using a microbrush in two steps to minimize porosities and light-cured after light curing the application of infiltrant should be repeated once again to minimize enamel porosity. Then, the surface is polished with polishing disc [Figures 1a-i].

Figure 1

(a) White spot lesion in 11 (preoperative); (b) rubber dam isolation; (c) application of ICON ETCH; (d) application of ICON DRY; (e) resin infiltration; (f) light curing; (g and h) postoperative; (i) 8 months follow up

Case report 2

A 21-year-old female patient reported with the chief complaint of white spot in her upper front teeth. An isolated white spot lesion was diagnosed in 21. Informed consent was obtained from the patient and treatment plan was established as Caries infiltration with ICON (DMG, Germany) [Figure 2a-h].

Figure 2

(a) Preoperative; (b) rubber dam isolation; (c) application of ICON ETCH; (d) application of ICON DRY; (e) resin Infiltration; (g and h) postoperative

DISCUSSION

Dental caries is a localised process, involving a progressive destruction of surface minerals by acids. Microorganisms which colonize on the tooth can produce acids in the presence of fermentable carbohydrates, and these acids diffuse into the healthy enamel surface and release hydrogen ions, which dissolve the underlying enamel (demineralization) and the dissolved minerals diffuse to the surface again and get precipitated.[4] It is also known as subsurface lesion because it has an apparently sound enamel surface underneath is an area of demineralization. The intact surface enamel is due to the reprecipitation of minerals (remineralization) dissolved from the subsurface.

RI of the sound enamel is 1.62, whereas the RI of the porous enamel is 1.33 when it is filled with watery medium and 1.0 when filled by air.[5] This significant difference in refractive indices, which causes changes in the scattering of light leading to the formation of white spots, termed as white spot lesion.[6]

The choice of treatment is always the application of remineralizing agents,[7] but these treatment modalities can cause only surface remineralization, the aim of this novel therapy is to occlude the subsurface microporosities and also to create a surface barrier within the body of the lesion and not on the surface.

The principle on which the masking effect happens is based on the alteration in the RI of the porous subsurface medium.[6] Icon infiltrant is a clear hydrophobic light curable resin Tri Ethylene Glycol Dimethacrylate. It has a low viscosity, low contact angle, high surface tension and high penetration coefficient. The RI of the infiltrant is 1.47. The resultant RI is 1.52, which is close to that of healthy enamel, resulting in masking of the white spot lesion. The mineralized surface interferes with the resin penetration. To overcome this, the surface of the lesion is conditioned with 15% hydrochloric acid gel[8] (ICON ETCH, DMG).

Active lesions show better penetration than inactive lesion.[9] During the management of inactive lesion, ethanol can be used to evaluate the complete erosion of the surface. If there is evident color change after application of ethanol, sufficient erosion is being achieved. When the color change is not evident, ethanol has not reached the body of the lesion, so etching should be repeated.[2]

Caries infiltration occludes the microporosites in the subsurface, which produces a diffusion pathway for both acids and minerals, but the fate of the bacteria trapped in the base of the lesion can trigger the carious process.[9] There is enough evidence in the literature that these entrapped bacteria, when properly sealed are not detrimental and uncavitated lesions have comparatively less bacteria in the subsurface.[10] Resin infiltrates to the body of the lesion by capillary forces and forms resin infiltrated parts of the lesion, depth of infiltration of the resin is up to 100 μm.[11] It is considered to be a micro-invasive procedure because tissue prevention is maximum, When compared to microabrasion only 30–40 μm is eroded in this technique and erosion of the healthy and demineralized enamel is similar because no pressure is applied.[8]

The disadvantages of this technique are that Tri Ethylene Glycol Dimetha Acrylate is an hydrophobic resin which raises a question about the hydric stress and there is no enough literature about the aging of this kind of restorations.[6] Extending the application of this technique to other conditions that exhibit white spots such as fluorosis, hypoplasia, erosion, and trauma are also to be evaluated.[12]

CONCLUSION

This caries infiltration procedure bridges the gap between preventive therapies and conventional restorative therapies, which can sometimes be invasive. With the increasing demand on less invasive esthetic treatments, caries infiltration is a novel alternative for management of enamel white spot lesion. This technique not only arrests the lesion progression but also improves the esthetics, which is considered to be a positive side effect. Caries infiltration proves to be a micro invasive treatment of smooth-surface white spot lesions and also one that allows for the instant recovery of natural tooth appearance, resulting in high patient satisfaction.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.