Over the last decade it has been noted that there is an increasing incidence of white marks on erupting teeth. Some of this is due to a condition called Molar Incisor Hypoplasia (MIH) where both erupting incisors and first molars have white spots present. The prevalence of MIH has been documented to be in the region of 25-40% (Condo 2012). However, there are many other causes of white marks on teeth (Table 1). Whilst white marks and white lesions on anterior teeth can be a common appearance, there are many new treatment strategies to deal with these white marks and eradicate their appearance. In most cases, tooth whitening may be the first choice (Greenwall 2009) in improving the appearance of the white mark. As the background of the tooth whitens, the appearance of the white mark may fade as it blends into the whiter and lighter background. However, it is important to warn patients that the white marks may appear whiter and brighter initially as whitening commences. Direct composite bonding over the mark may also be necessary if there is a defect in the enamel surface and the enamel surface is not intact.
A new technique using resin infiltration has been introduced (Munoz et al 2013) to treat anterior white marks. The purpose of this clinical article is to assess the use of this resin infiltration technique for anterior and posterior lesions. A step-by-step approach will be described.
History of Resin Infiltration
Initially resin infiltration was used as a method of treating incipient caries (Meyer – Lueckel et al 2008) either interproximally or on the smooth surfaces of teeth. The low viscosity resin infiltrant (Paris et al 2012) was used to occlude the pores within the hypomineralised lesion. The hypomineralised enamel permits diffusion pathways for acids and dissolved minerals, which continues through the enamel of the affected area. The resin infiltration technique seals these pathways (Paris et al 2010) and prevents further deterioration of the area. Thus caries infiltration techniques can also be used to camouflage aesthetically disfiguring white spot lesions on buccal surfaces. Whilst extensive research has been undertaken on the resin infiltration treatment for caries, a further use of the technique has been explored for the aesthetic treatment of white spots (Tirlet and Attal 2011).
Aetiology of White Marks
There are several treatment options for treating anterior white spots on the labial surfaces of teeth:
1. Tooth whitening.
2. Application of amorphous calcium phosphate directly to the lesion or in a bleaching tray (Abreu et al 2011) (Fig. 5).
3. Microabrasion using 6.6% hydrochloric acid (Greenwall 2006, product used Opalustre, Optident UK) and 10 percent hydrochloric acid (Premier Products, USA) (Fig. 3).
4. Resin Infiltration using 15 percent hydrochloric acid (Icon, DMG, Germany).
5. Combination therapy using whitening and increasing concentrations of hydrochloric acid.
6. Advanced lesion treatment includes sandblasting the white lesion first followed by resin infiltration. The sandblasting permits deeper penetration of the icon resin (Figs. 19 & 20).
7. Composite bonding directly over the lesion or defective enamel.
8. Removing the white mark with a fast hand piece and restoring with composite resin, dentine, enamel and opaque shades.
9. Direct resin veneer.
10. Indirect resin veneer (Edelweiss, Optident UK).
11. Porcelain laminate over the whole labial surface.
Amorphous Calcium phosphate is applied to the teeth after the microabrasion session to strength the enamel. The ACP is absorbed into the surface defects to assist with improving the enamel surface texture.
Opaluster Microabrasion paste is polished onto the white spots, to blend/eradicate the white spots and to treat and smooth the enamel surface, which was rough and slightly pitted.
Large white lesion prior to treatment. This is an advanced case due to the large opaque nature of the white area.
Following whitening treatment, the white mark was removed with Icon resin infiltrant. This was treated in three treatment sessions to remove the area completely.
Classification of lesion size can also be according to aetiology, location and size. The sizes of white marks vary and for the purpose of this article they will be classified as small, medium and large. When starting to use the resin infiltration treatment, it is easier to begin treating smaller white lesions as smaller white marks are easier to remove than the larger patches. The medium to large size patches may require two to three treatments. If the lesion is very deep, then it is advisable to sandblast the white area prior to applying the hydrochloric acid as an etch to the tooth. The sandblasting helps to open up the enamel tubules so that better penetration of the hydrochloric acid can be achieved. Sand blasting can be undertaken each session prior to etch placement or treatment can be undertaken as a sandblast-etch- alcohol, sandblast-etch-alcohol cycle.
1. Small white lesions inherent on the tooth.
2. Smooth surface white decalcification on the tooth such as after stasis of plaque after orthodontic treatment, or early smooth surface caries resulting from poor oral hygiene.
3. Larger white marks and bands on the tooth.
4. Lesions due to molar incisor hypoplasia (MIH).
5. Hypoplasia stains due to traumatic injuries.
6. Mild to moderate fluorosis.
7. Large single bands due to fluorosis.
8. Twins and patients who are born prematurely are prone to white spots. These can be often removed with resin infiltration.
The Resin Infiltration Technique
The resin infiltration technique was introduced as a method of reducing the size of carious lesions in enamel (Paris et al 2010), especially non-cavitated initial caries (International Caries Detection and Assessment system ICDAS code 1 and 2) (Arnold 2016). The resin was meant to infiltrate into the hypomineralised enamel and arrest the developing caries (Pharck et al 2009). Whilst this technique can be used for interproximal and smooth surface caries (Kugel et al 2009), a further use has been suggested, that of eradicating surface white spots and marks on the buccal and labial surface of anterior teeth. The use of resin infiltration interproximally was the only way of sealing the interproximal surface, thus improving the inhibition of caries progression (Pharck 2009). This resin infiltration can delay the time for restoration placement and thus closes the gap between non- invasive and invasive treatment options (Pharck 2009) (Figs. 13-18).
Preparation of the posterior teeth to receive Icon Resin Infiltrant.
Isolation with Rubber dam, matrix for separation of the acetate strip.
The special interproximal acetate, which is applied for the posterio placement, has holes designed on one side so that the etchant and the resin only reach one side of the designated tooth.
Icon etchant is applied to the tooth for two minutes.
After alcohol placement, the resin is applied.
The appearance at the end of treatment with the resin applied.
Resin infiltration can also be used for anterior interproximal lesions (Calgar et al 2015). The study evaluated 21 proximal infiltrates on incisors and premolars over a four-year period. Their results demonstrated radiographically that that the resin infiltration arrested the caries from progressing further. Discolouration was noted in the resin on four teeth. This discolouration was detected each year over a four-year period. It is thought that the discolouration is related to poor oral hygiene of the patient.
There is new research to demonstrate that Icon (DMG) may be useful to delay tooth wear and stabilise small erosion. The area is first etched using 15% hydrochloric acid (Fig. 16). Alcohol is then placed over the lesion. Resin is then infiltrated into the lesion and light cured (Fig. 17). The lesion fades as the micro porosities are infiltrated with resin (Figs. 1 & 7). Surface roughness decreases after resin infiltration (Arnold 2016).
Shade tab showing the base shade of the teeth. The yellow and white banding is very visible. The aetiology is thought to be antibiotics given as a child.
Icon resin infiltration was applied to the remaining white areas on the tooth. These white areas were eradicated using the Icon Resin Infiltration. This photo shows the final result after bleaching, microabrasion and Icon white spot infiltration.
The Technique Consists of Three Components
1. The preparation phase – the surface of the teeth is cleaned and prepared with 15% hydrochloric acid for two minutes (Fig. 16).
2. Alcohol is placed onto the surface as a drying agent and left for two minutes.
3. The TEGMA resin is applied onto the tooth for two to five minutes (Fig. 17).
4. The tooth is light cured.
1. Isolation – good isolation is essential as the initial phase uses a strong acid for etching the tooth. This can be via a rubber dam (Fig. 13) or an Optragate isolation retractor (Optragate lip and cheek retractor, Ivoclar Vivadent, UK).
2. The surface of the tooth is cleaned with a mixture of pumice and Hibiscrub (chlrohexidine).
3. If there is a very large white lesion, this can be sand blasted first using a microetcher (Danville, USA) directly onto the white mark.
4. The preparatory phase – 15% hydrochloric acid is applied directly onto the lesion with a special applicator for anterior teeth which resembles a small circular sponge. There is also a special posterior applicator (Figs. 15-17).
5. This is left in place for a period of two to five minutes (normally two minutes).
6. The tooth is rinsed with water.
7. Alcohol (Ethanol – Icon Dry) in a syringe is applied directly onto the white lesion. This is dried. The alcohol is applied onto the surface of the lesion to act as a drying agent and to change the refractive index of the surface of the enamel. This will assist in assessing whether the resin will make a difference in erasing the white lesion completely or whether further sand blasting and hydrochloric acid etching will be necessary.
8. TEGMA resin is applied directly onto the dried white mark.
9. This is left in place for three minutes.
10. The tooth is light cured for 40 seconds.
11. Observation of the result can be undertaken and reviewed.
12. Further Icon resin is applied to the tooth for a second layer for one minute.
13. The area is flossed so that there is no resin catching interproxially.
14. The area light cured for 40 seconds.
15. On anterior lesions, the labial surface is polished and smoothed with a soflex disc.
16. Photos taken.
Should Bleaching of the Tooth Be Done First?
Depending on the size of the lesion, it is always best to undertake bleaching first (Greenwall 2009) and this may reduce the size of the white mark and the entire appearance of the lesion.
In a study undertaken by Munoz et al (2013) where suitable cases were infiltrated with resin, they found that the most successful cases were the ones with fluorosis stains. These cases showed visibly perceptible differences. The hypoplasia areas were not completely eradicated. The researchers reported that the patients recovered their self-esteem, as a result of the treatment and thus this was considered as a success. The effect of the hydrochloric acid on the enamel was evaluated in a study by Paris et al (2010). These researchers evaluated the etching effect of hydrochloric acid vs phosphoric acid on deciduous teeth. They evaluated 36 pairs of primary molar enamel lesions. The lesions were etched for two minutes with both phosphoric acid and hydrochloric acid and then examined under confocal microscopy. They reported that there was a difference between the two acids on the surface of the teeth and that the hydrochloric acid caused higher erosion on the enamel, thus allowing deeper penetration of the resin infiltrant. The erosion depth of the hydrochloric acid was twice the depth of the phosphoric acid. Phosphoric acid at an etching time of two minutes cannot erode the surface of the enamel. It seems that the resin infiltration technique can reduce long-term restorative needs and costs. This contributes to the minimal invasive approach and the entire enamel surface remains intact and is preserved without the need for further restorative treatment (Kielbassa et al 2009).
Varying Results of the Resin Infiltration Technique
1. The resin infiltration technique may not always fade the white spot lesion entirely. This may improve over time. In a study by Kim et al (2011) 20 teeth with a developmental defect of enamel and 18 teeth with post orthodontic decalcification were selected to have resin infiltration. Standardised photographs were taken before, immediately after and one week after treatment. The results were classified into three different groups: completely masked, partially masked and unchanged. The image analysis of the delta E results showed that 25%5 of teeth were classified as completely masked whereas 35%7 were partially masked and 40%8 unchanged.
2. Partial change of the white area – Of the post orthodontic decalcification group 61%11 of teeth were completely masked, 33%6 were partially masked and 6%1 was unchanged. For some teeth the result improved after one-week post infiltration rather than immediately after the infiltration. They concluded that the masking effect was dramatic in some cases but not in others. Further research on the long-term effects should be continued.
3. No change initially – Deeper penetration may be required. Through a continuous phase of sandblasting, etching and alcohol, the tooth can be treated for three to five applications prior to placement of the resin. Deeper penetration can be achieved by sandblasting first. Further treatment sessions can be undertaken two to three weeks apart. The resin does continue to work on the tooth over time and thus it is advisable to wait between treatment sessions for the resin to take effect. With further experience, we now know that the lesions that do not respond to complete white spot removal can be treated again.
4. White halo – incomplete treatment of the white area. Further sandblasting and etchant must be done.
Results after two weeks of whitening. Notice that the white has totally faded and the white appears whiter. There were enamel surface defects on the surface of the teeth.
Teeth are rehydrated with water in between each application.
Results after bleaching and microabrasion. There are still white areas visible, which were not eradicated with the microabrasion technique.
Early mesial posterior caries is visible on the lower right first molar (enamel hypomineralisation) during orthodontic treatment.
The etchant visible on the interproximal surface. It was difficult to apply the rubber dam in this situation due to the orthodontic brackets being present.
The early caries have been dramatically reduced.
A PA taken two years later showing no sign of decay.
This figure shows the posterior acetate applicator, which is placed onto the Icon Etchant.
There is still further research to be undertaken as there are many unanswered questions: How can it be determined which lesions will respond with complete eradication of the white spot and which with only partial eradication? Should bleaching be undertaken before resin infiltration and will this improve the overall result? What is the effect of the TEGMA resin on further bonding techniques – will the bond be as stronger or weaker?
The resin infiltration techniques have opened up a new range of options for the treatment of white spots in a minimally invasive way. As further research unfolds more treatment modalities will become available using the resin infiltration technique. This will help to improve aesthetic outcomes for patients as well as conserve healthy tooth structure. OH
Oral Health welcomes this original article.
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About the Author
Dr. Greenwall is a specialist in Restorative Dentistry and Prosthodontics. She is an international lecturer and an authority on tooth whitening, aesthetic dentistry and practice management. As well as running a multidisciplinary private practice in Hampstead, London where she works with a specialist team in the practice which has an Endodontist, Periodontist, Implant Surgeon, Oral Surgeon and Orthodontist. She is an immediate past Chairperson for the Alpha Omega Society 2012/13 and Editor-in-chief of the journal Aesthetic Dentistry Today and is President of the British Dental Association for the Metropolitan London Branch for 2015/2016.