Novel treatment of white spot lesions: A report of two cases.

This case report describes a technique used to treat smooth surface white spot lesions microinvasively. It is based on the infiltration of an initial enamel caries lesion with low-viscosity light-curing resins called infiltrants. The surface layer is eroded and desiccated, followed by resin infiltrant application. The resin penetrates into the lesion microporosities driven by capillary force and is hardened by light curing. Infiltrated lesions lose their whitish appearance and look similar to sound enamel. Additionally, the treatment prevents lesion progression. This technique might be an alternative to microabrasion and restorative treatment in treating of white spot lesions of esthetically relevant teeth.

INTRODUCTION

White spot lesions are early signs of demineralization under intact enamel, which may or may not lead to the development of caries. The reason for white spot is that the pathogenic bacteria have breached the enamel layer, and organic acids produced by the bacteria have leached out a certain amount of calcium and phosphate ions that fails to replace naturally by the remineralisation process. This loss of mineralized layer creates porosities that change the refractive index of usually translucent enamel.[1]

White spots may also be seen after removal of orthodontic bands and brackets.[2] Adjunct causes of white spot lesion may include heavy plaque accumulation, inadequate oral home care routines and a high sugar or acid content diet.[3]

TREATMENT OF WHITE SPOT LESION

The first line of treatment of white spot is remineralisation. There are creams, pastes and topical remineralisation treatments such as fluoride therapy, casein–phosphopeptide–amorphous calcium phosphate pastes, Novamin (calcium sodium phosphosilicate), invasive approaches such as microabrasion, conventional bonding and various types of veneers.[4]

A new minimally invasive technique for treating white spot lesions is by caries infiltration, a product of “DMG,” called “Icon.”

This icon prevents further progression of initial enamel caries lesions and occludes the microporosities within the lesion by infiltration with low-viscosity light-curing resins that can rapidly penetrate into the porous enamel. The resin completely fills the pores within the tooth, replacing the lost tooth structure and stopping caries progression.[56] After conditioning of lesions using 15% hydrochloric acid gel, dessicating the tooth with ethanol is performed, which allows easy penetration of resin into the porous tooth.[7] The resin penetrates into the lesion by capillary forces and creates a diffusion barrier inside the lesion and not on the lesion surface.[78]

The advantage of resin infiltration is that enamel lesions lose their whitish appearance when their microporosities are filled with the resin and look similar to sound enamel.

CASE REPORT

A 19-year-old female patient named Ms. Ashwini reported to the Outpatient Department of Conservative Dentistry and Endodontics, College of Dental Sciences, Davangere, Karnataka. She presented with a chief complaint of white spot in the mandibular right anterior area since 5–6 months. On oral examination, there was a carious white spot lesion in relation 31, extending horizontally at the incisal third of the tooth [Figures 1a to i] and another male patient named Mr. Sandeep, of age 20 years, presented with the chief complaint of white spot in the maxillary left anterior area since 2 months. On oral examination, it was also diagnosed as a white spot lesion in relation to 21 and 22 at the incisal third of the tooth [Figure 2a–f].

Figure 1

(a) Preoperative picture showing incipient caries in the lower central incisors. (b) Preoperative picture. (c) Application of Icon Etch for 2 min. (d) Rinsing of Icon Etch after 30 s. (e) Application of Icon Dry for 30 s. (f) Air drying. (g) Application of Icon resin and allowing penetration for 5 min. (h) Light curing the resin. (i)Postoperative picture

Figure 2

(a) Preoperative picture showing incipient caries around the orthodontic brackets on upper left incisors 21 and 22. (b) Application of Icon Etch for 2 min. (c) Appplication of Icon Dry. (d) Application of Icon resin and allowing penetration for 5 min. (e) Light curing the resin. (f) Postoperative picture

The following clinical procedures were conducted: rubber dam is applied to protect soft tissue and achieve clean and dry working condition. After oral prophylaxis of teeth, the surface of the white spot is eroded by application of a 15% hydrochloric acid gel (Icon etch) for 2 min[6] and stirring the gel from time to time during application with a microbrush. Subsequently, the etching gel is thoroughly washed for 30 s using a water spray. The etching procedure removes superficial discolorations and the higher mineralized surface layer, which might hamper resin penetration. The lesion is desiccated by applying ethanol (Icon-Dry) for 30 s followed by air drying. Icon resin composed of tetraethylene glycol dimethacrylate is applied on the lesion surface using a microbrush and allowed to penetrate for 5 min.[910] The excess is removed using a cotton roll and light cured. The application of infiltrant should be repeated once to minimize enamel porosity. Finally, the rough surface is polished using disks and silicone polishers to avoid rediscoloration by food stains.[9]

DISCUSSION

The following case report showed that after 3-months follow-up, there was no progression of white spot lesion and there was an improvement in the esthetics on clinical examination.

This observation was in accordance with the study performed by the author Meyer-Lueckel and Paris, which showed that resin mixtures with high TEGDMA (triethylene glycol dimethacrylate) concentrations tended to show better inhibition of lesion progression than those with high concentration of BISGMA (bisphenol A glycidyl methacrylate), which was due to better penetration capabilities after application of ethanol.[10]

Another study conducted by Paris and Meyer-Lueckel showed that infiltrated enamel lesion progression was significantly more slow when compared with untreated lesions in a highly cariogenic environment.[6]

Meyer-Lueckeln et al. also showed that etching with 15% hydrochloric acid gel leads to a more effective erosion of the surface layer compared with 37% phosphoric acid gel.[711]

Based on these studies, it is shown that the resin arrests the progression of white spot by occlusion of the microporosities that provide diffusion pathways for acids and dissolve minerals; it also blocks the further introduction of any nutrients into the porous system.

Secondly, the white opaque appearance of the lesion can be masked by using resin infiltration. The principle of masking enamel lesion by resin infiltration is based on changes in light scattering within the lesion, which was proved by the study conducted by the authors Kidd and Fejerkaro, who stated that the enamel has a refractive index of 1.62. In the subsurface lesion, the pores are filled with a watery medium with a refractive index of 1.33. The difference in refractive index between the water and the enamel affects light scattering and makes the lesion look opaque. The microporosities of the enamel caries lesion are filled with either a watery medium (R.I. of 1.33) or air (R.I of 1.0). The microporosities of infiltrated lesions are filled with resin (R.I. of -1.46), which, in contrast to the watery medium, cannot evaporate. Therefore, the difference in refractive indices between the porosities and enamel is negligible and lesions appear similar to the surrounding sound enamel.

DMGs Icon Resin is a new microinvasive technology that will fill, reinforce, stop the caries progression and mask the enamel white spot lesions.

The main aim or objective of the caries infiltrant is to arrest caries progression by occlusion of the microporosities that provides diffusion pathways for acids and dissolved minerals[1012] ; it also blocks the further introduction of any nutrition into the porous system and there is improvement in the esthetics.

This new technique is contraindicated in other causes of white spot lesion, like flurosis, hypoplasia, hypocalcification, erosion, tetracycline staining and trauma.

CONCLUSIONS

Cosmetics and esthetics are current trends of our society, as more and more patients are demanding for minimally invasive cosmetic enhancement without anesthesia, drilling and less-expensive restorations. This technique may be considered as a microinvasive treatment of smooth-surface white spot lesions and also one that allows for the recovery of natural tooth appearance. However, more clinical data are needed.