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Resin Infiltration for Post-Orthodontic White Spot Lesions: A Case Report
*Corresponding author: Nguyen Thi Hai Anh, School of Dentistry, Hanoi Medical University, Hanoi, Vietnam. nguyenhaianhbk@gmail.com
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Received: ,
Accepted: ,
How to cite this article: Hai Anh N, Huong L, Nhu Ngoc V, Tuan Anh N. Resin Infiltration for Post-Orthodontic White Spot Lesions: A Case Report. Dent J Indira Gandhi Int Med Sci. 2025; doi: 10.25259/DJIGIMS_34_2025
Abstract
Patients using Clear Aligners (CAs) face an increased risk of dental caries due to reduced salivary flow while wearing the aligners. White Spot Lesions (WSLs) can be managed through remineralization therapy. However, this approach requires a considerable amount of time and high patient compliance. To explore the application of the resin infiltration method for treating WSLs. This clinical case report discusses the resin infiltration treatment of a 13-year-old male patient with post-orthodontic caries following CAs. The patient had previously undergone unsuccessful remineralization therapy. Following resin infiltration treatment, the white spots caused by caries were successfully corrected, resulting in aesthetic improvements in the incisor region, with minimal invasiveness . Resin infiltration offers an effective and minimally invasive treatment option for aesthetically managing WSLs caused by dental caries, leading to high restorative success and patient satisfaction in clinical cases.
Keywords
Clear aligners
Icon resin infiltration
Minimally invasive dentistry
Resin infiltration
White spot lesions
INTRODUCTION
Dental caries is a common condition resulting from demineralization, leading to increased porosity and changes in color, gloss, and the structure of tooth tissue. White Spot Lesions (WSLs) on the enamel surface, which have not yet progressed to cavities, are a typical sign of early-stage dental caries. These lesions can be detected when the tooth surface is dry or moist.[1]
Saliva acts as a natural protective mechanism against dental caries by helping to wash away debris and maintain pH balance in the oral cavity.[2] However, in patients wearing Clear Aligners (CAs), the risk of dental caries increases due to reduced saliva flow during the use of trays.[3] WSLs can be treated with remineralization therapy, which involves mechanical plaque removal and the use of fluoride-containing products, either in low concentrations at home or higher concentrations prescribed by a dentist. While effective, this treatment requires significant time and patient compliance.
The resin infiltration method, commonly known as ICON resin infiltration, is a minimally invasive technique designed to fill and stabilize demineralized enamel.[4] This report aims to describe and demonstrate the application of resin infiltration for treating WSLs caused by post-orthodontic caries, specifically in the aesthetic area.
CASE REPORT
A 13-year-old Vietnamese male was referred for evaluation and management of dental caries following the completion of orthodontic treatment with Invisalign® CAs at Nhu Ngoc Dental Clinic (Dong Da District, Hanoi, Vietnam) in June 2024.
Patient history
The patient's medical history was non-contributory, with no systemic conditions or history of trauma to the primary incisors. This excluded the likelihood of enamel hypomineralization secondary to trauma affecting the developing permanent teeth. Additionally, the patient resided in a non-fluoridated area, minimizing environmental fluoride exposure.
According to the orthodontist’s clinical records, no signs of enamel demineralization or initial carious lesions were detected on the labial surfaces of the anterior teeth prior to, or during, the first 4 months of orthodontic treatment. However, after this period, the patient reported a habit of consuming carbonated beverages daily without removing the aligners and without performing oral hygiene procedures afterward. Despite repeated instructions and warnings from the treating dentist regarding oral hygiene maintenance, the patient missed two consecutive monthly follow-up visits, contributing to the progression of the carious lesions.
Upon follow-up examination, multiple WSLs were observed on the enamel surfaces across both dental arches [Figure 1]. The patient had previously received oral hygiene instructions and was advised by the orthodontist to apply natural remineralization strategies, including the use of 5% sodium fluoride (NaF) varnish. However, no clinical improvement was noted, which was attributed to poor compliance with the recommended preventive measures.
- Before treatment. Front view of teeth 11, 12, 21. White spots can be seen in wet conditions on the outer surface. In some areas, the lesions have turned yellow brown. Photo taken with NIKON D810 camera, f=105mm.
Clinical findings
Intraoral examination revealed that the labial enamel surfaces of teeth #11, #12, and #21 exhibited diffuse white opacities, accompanied by localized yellow-brown discoloration. Following thorough prophylaxis, including the removal of plaque and calculus, the affected areas were evaluated using an early caries detection device (EP Light Transilluminator, EPDENT, Korea). The white lesions demonstrated ill-defined margins, suggestive of subsurface enamel demineralization [Figure 2].
- Lesions observed through EP light transilluminator (EPDENT, Korea).
Based on the patient’s medical history and clinical presentation, the lesions on teeth #11, #12, and #21 were diagnosed as early-stage caries, corresponding to Code 3 according to the International Caries Detection and Assessment System II (ICDAS-II). Subsequently, caries management was initiated. Posterior teeth, including premolars and molars, were restored using light-cured composite resin restorations (3M, USA). For the maxillary anterior teeth, where aesthetic demands were higher, Resin Infiltration Therapy (DMG, Germany) was performed to arrest lesion progression and improve enamel appearance. The procedure was explained in detail to both the patient and his guardians, including the expected aesthetic outcomes and potential risks such as gingival irritation. Informed consent was obtained prior to treatment.
Treatment protocol
ICON® resin infiltration system (DMG, Germany) was employed. A rubber dam (YDM, Japan) was placed to achieve effective isolation of the affected teeth from oral fluids. Given that the lesions were confined to the incisal two-thirds of the labial enamel surfaces, additional isolation [Figure 3] using dental floss at the cervical margin was avoided to minimize trauma to the adjacent gingival tissues. Adjacent teeth and gingival areas were protected using a light-cured resin barrier (OpalDam®, Ultradent, USA).
- Isolated with a rubber dam.
Micro-abrasion procedure
To achieve superficial enamel reduction in a minimally invasive manner, a micro-abrasion technique was employed. A fine abrasive slurry (Opalustre®, Ultradent, USA) was applied directly onto the WSLs for 60 seconds, using gentle circular motion. The treated area was subsequently rinsed thoroughly with water for 40 seconds to remove all residual material [Figure 4].
- Micro-abrasive process.
Etching and lesion assessment
After exposing the hypomineralized enamel surface, the area was etched using Icon-Etch® (DMG, Germany), a 15% hydrochloric acid (HCl) gel. The etching agent was actively agitated in a circular motion on the enamel surface for 2 minutes to enhance penetration via increased friction and localized heat generation. Following this, the surface was thoroughly rinsed with water for 30 seconds.
Subsequently, Icon-Dry® (DMG, Germany), composed of ethanol, was applied to the treated area to desiccate the enamel and allow visual assessment of the WSLs. The etching-drying sequence was repeated six times until a significant reduction in lesion visibility was achieved, indicating sufficient erosion and infiltration potential [Figure 5].
- Etching surface with 15% HCl, then rinse and dry with ICON-Dry (alcohol-based).
Resin infiltration
Following adequate etching and drying, Icon-Infiltrant® (DMG, Germany) was applied [Figure 6] to the hypomineralized enamel surface in two stages. During the first application, the low-viscosity resin was allowed to infiltrate the enamel porosities for 3 minutes, then light-cured for 40 seconds using a high-intensity LED curing unit (DTE Lux E Plus, DTE, China).
- Resin infiltration.
A second application of the infiltrant was then performed for 1 minute to compensate for any resin shrinkage and ensure optimal lesion saturation. The infiltrated surface was subsequently covered with a glycerin-based gel to prevent the oxygen-inhibited layer from forming during polymerization, followed by a final light-curing step for 40 seconds.
Finishing and follow-up assessment
Upon completion of resin infiltration and polymerization, the treated enamel surfaces were gently polished [Figure 7] using the Komet™ 4652 composite polishing kit (Komet, Germany) to remove excess material, smooth the surface, and enhance aesthetics. Final intraoral photographs were taken for documentation and comparison [Figures 8-9]. Total treatment time, excluding consultation and data photography, is 1 hour and 30 minutes for all three teeth. After treatment, patients are advised to limit the use of foods and drinks that can easily cause staining, continue oral hygiene maintenance, dietary modifications, and regular dental check-ups to prevent recurrence or development of new lesions.
- Polishing.
- 2-hour post-treatment. Front view of teeth 11, 12, 21 (Photo taken with NIKON D810 camera, f=105mm).
- 2 hours post-treatment. Teeth 11, 12, 21 exposed to the EP light transilluminator (EPDENT, Korea).
At the 2-week follow-up [Figure 10], the patient reported no postoperative sensitivity or discomfort. Clinically, the infiltrated lesions exhibited a significant reduction in opacity and color discrepancy, with esthetic outcomes well accepted by both the patient and caregivers. Evaluation was performed using a Visual Analog Scale (VAS) for esthetic satisfaction and a simplified Lesion Visibility Score (LVS), in which the treated surfaces were rated based on residual white opacity. The post-treatment LVS showed improvement from Grade 3 (clearly visible WSL) to Grade 1 (barely visible or indistinguishable from surrounding enamel), and the average score of VAS was 9/10 (ranging from 0- “not satisfied” to 10-“extremely satisfied”).
- 2-week post-treatment (Photo taken with NIKON D810 camera, f=105mm).
DISCUSSION
WSLs are a common adverse effect of orthodontic treatment, especially in patients with poor oral hygiene and frequent sugar intake. These lesions represent the early stage of enamel demineralization and may persist or worsen without timely intervention. Although CAs are considered to have a lower risk of caries than appliances, if the patient does not comply with the dentist's instructions for maintaining oral hygiene, wearing aligners can cause extensive caries with greater severity and rate. Therefore, the success of orthodontic treatment depends significantly on the cooperation between the dentist and the patient during and after treatment.[5] In this case, the patient's daily consumption of carbonated beverages while wearing CAs, combined with poor oral hygiene compliance, significantly contributed to the rapid development of WSLs.
Treatment of white spots should begin with conservative procedures and then progress to more invasive methods when necessary.[6] Conventional management of WSLs includes fluoride varnish application and casein phosphopeptide-amorphous calcium phosphate (CPPACP) to promote remineralization. However, their esthetic outcomes are often unpredictable and limited in visibly reversing lesion appearance, especially in more advanced lesions with deep porosities. Studies have shown that fluoride alone is insufficient for the cosmetic improvement of WSLs once enamel opacity is clinically visible.[7]
Resin infiltration method, also known as ICON resin infiltration, introduced by Meyer-Lueckel and Paris, is known to be an effective method in the treatment of WSLs in the early stages of dental caries, especially within the first 3 months after the appearance of the lesions.[8] The infiltrant (ICON®, DMG) fills the intercrystalline spaces within the lesion body, blocking further diffusion pathways for cariogenic acids and achieving significant masking effects. Several in vitro studies have shown that the depth and penetration time of resin infiltration on the tooth tissue are significantly better than those of high-concentration fluoride products applied to the surface.[9,10]
In our patient, lesion visibility was notably reduced from ICDAS code 3, and the esthetic outcome was positively evaluated both subjectively and objectively. The polishing step further enhanced surface gloss and patient satisfaction. Importantly, no postoperative sensitivity was reported, affirming the biocompatibility and patient-centered advantages of this method after 2 weeks of treatment. We have not yet noticed any discoloration in the areas where the resin material has penetrated, however, we still need a longer follow-up period to ensure the product's color fastness and anti-oxidation ability and time duration in dental chair for each case is still longer than other methods, which can easily cause fatigue for patients when they have to lie still in one position and open their mouths for a long time, especially for uncooperative young patients.
CONCLUSION
Resin infiltration represents a minimally invasive and esthetically favorable approach for the management of early enamel lesions, particularly in the anterior region. Compared to conventional remineralization techniques, this method provides more immediate and visible improvements in appearance. Additionally, it preserves tooth structure more effectively than traditional restorative interventions, offering a conservative alternative for managing incipient carious lesions.
Ethical approval:
Institutional Review Board approval is not required.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript, and no images were manipulated using AI.
Financial support and sponsorship: Nil.
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