Abstract | | |
Dental fluorosis is caused by ingestion of excessive fluoride during tooth development resulting in hypomineralization of the enamel and can present as white or brown intrinsic lesions. This case report describes a combination of minimally invasive techniques: microabrasion, bleaching, and resin infiltration to address brown enamel fluorosis present on the maxillary anterior teeth of a young patient. Before resin infiltration, air microabrasion was targeted at subsurface lesions located on the maxillary central and lateral incisors, and chairside bleaching was done with 37% hydrogen peroxide (Opalescence). After which, hypoplastic lesions on the buccal surfaces were etched before being treated with two sessions of resin infiltration (ICON and DMG). Following treatment, satisfactory esthetic outcomes were achieved. Accurate diagnosis, depth of lesions, and understanding the effectiveness and limitations of each technique are essential to select the appropriate type of treatment to obtain the best esthetic outcome. In conclusion, the conservative management of varying severity of dental fluorosis may require the appropriate use of combination treatment modalities, such as microabrasion, bleaching and resin infiltration, when clinically indicated, to address the treatment needs and achieve a desired outcome.
Keywords: Bleaching; color science; dental materials; microabrasion; operative dentistry; restorative dentistry
How to cite this article: Nicholas LS, Yew Christopher QE, Fei Frank LK. Conservative esthetic management of brown enamel fluorosis using combination therapy: A clinical report. J Conserv Dent 2023;26:349-54 |
How to cite this URL: Nicholas LS, Yew Christopher QE, Fei Frank LK. Conservative esthetic management of brown enamel fluorosis using combination therapy: A clinical report. J Conserv Dent [serial online] 2023 [cited 2023 Jun 1];26:349-54. Available from: https://www.jcd.org.in/text.asp?2023/26/3/349/362926 |
Introduction | |  |
Definition
Dental fluorosis is defined as the hypomineralization of enamel, resulting from systemic absorption of high concentrations of fluoride during tooth development, which disrupts proper amelogenesis.[1] Dental fluorosis can vary in appearances, depending on the quantity, frequency, and age of exposure during tooth development. Mild fluorosis may present as indistinct white streaks following the parenchyma, cuspal snow capping, and snowflaking appearance, without a clear demarcation with the unaffected surrounding enamel. Whereas, in severe fluorosis, staining can range from yellow to dark brown discoloration and even pitting of surface enamel from mechanical breakdown.[2],[3]
Diagnosis/description of lesion
Historically, the various indices used to classify fluorosis, such as the Dean's fluorosis index (1942)[4] and Thylstrup and Fejerskov index (TF index) (1978),[5] were based on grading of the severity of fluorosis and using esthetic deviation as a parameter of identification. More recently, the Tooth Surface Index of Fluorosis (TSIF) was introduced by Horowitz et al.[6] to describe the extent of enamel fluorosis and classified individuals into eight categories depending on the color and depth of lesion. This proved to be clinically more relevant as the diagnostic criteria and analysis were based on esthetic concerns.[7] As most patients with mild–moderate fluorosis are often unaware of their condition, only those with severe fluorosis and esthetic concerns will seek dental intervention.[8]
Treatment options
Treatment options for teeth affected by fluorosis are selected according to the patient's concern, severity of lesions, and treatment objectives. A thorough evaluation of the severity can aid in the appropriate recommendation of treatment modalities to improve esthetics.[1],[9] For example, noninvasive or minimally invasive treatment options are typically recommended for TF scores 1–4, while more aggressive techniques are recommended for pitted fluorosis with TF scores ≥5.[10] Possible noninvasive methods include microabrasion,[11],[12] macroabrasion (complete removal of surface stained areas), bleaching, composite CR, resin infiltration, and combination approaches, while invasive approaches include laminates, veneers, or crowns.[13] As majority of patients seeking treatment for dental fluorosis are of the younger age group, aggressive prosthodontic treatment options will result in earlier significant tooth structure loss, which is not only procedurally tedious and expensive but also premature and irreversible.[14] Hence, minimally invasive techniques, whenever possible, should be recommended for younger patients.
Bleaching with hydrogen peroxide (H2O2) or carbamide peroxide has been considered as least invasive among the minimally invasive techniques and been used in children and adolescents successfully.[12] However, in-office bleaching with high H2O2 concentrations can be caustic to soft tissues;[15] hence, precautionary measures to protect the soft tissues must be taken during use.
The resin infiltration technique was originally introduced for arresting early caries,[16] proximal caries,[17],[18] and subsequently used for the esthetic management of white lesions associated with enamel hypomineralization.[19],[20] This minimally invasive approach has proven to be effective in addressing white fluorosis stains,[21] given that the fluorotic subsurface hypomineralization underneath a relatively well-mineralized superficial enamel can be adequately infiltrated.[22] The ability of resin infiltration to mask unesthetic white spots clinically[23] allows this technique to be utilized to enhance the appearance of teeth with fluorosis and hypoplastic lesions,[24] as well as developmental defects.[25] However, a recent study highlighted that teeth managed with resin infiltration lack durability and might be susceptible to extrinsic stains.[26]
This case report describes the use of conservative combination therapy of microabrasion, bleaching, and resin infiltration, to enhance the esthetic outcome of a patient with moderate brown dental fluorosis.
Case Report | |  |
Background
A 19-year-old Chinese female presented at the *Faculty of Dentistry*, Prosthodontic department, “I do not like the brown spots on my front teeth.” The patient was highly aware of the well-demarcated brown lesions present on her maxillary central and lateral incisors. The incisors were made more obvious because of her gummy smile [Figure 1].
The patient had no relevant medical history. She recalled periods during her childhood (around 5 years old) where she frequently ingested adult fluoridated toothpaste resulting in greater systemic intake of fluoride, causing the fluorosis.
Clinically, the patient presented with Angle's Class II incisal relationship, deep overbite (5 mm), high smile line,[27] downward lip curvature,[28] correct axial inclination of the maxillary anterior teeth, healthy moderate periodontal biotype, and scalloped gingival tissues. The oral hygiene was fair, with moderate plaque and calculus, caries free, and no prior history of restorative treatment. The brown lesions located on the maxillary incisors had a nonpitted appearance, smooth surface, and limited to the cervical third to incisor thirds of the tooth. These lesions were diagnosed as dental fluorosis and were given a TSIF score of 4 [Figure 2]. Radiographically, the maxillary teeth displayed normal bone levels, periodontal ligament space, and intact lamina dura.
Treatment
Considering the patient's young age, a more conservative approach was taken. The initial treatment plan presented to the patient was ICON resin infiltration (DMG, Hamburg, Germany). ICON Resin starter pack consists of ICON-etch (15% hydrochloric acid, pyrogenic silicon acid and surfactant based), ICON-dry (99% ethanol based), and ICON infiltrant (methacrylate-based resin).
First, the teeth were cleaned with pumice and water slurry, rinsed, and a conventional rubber dam was placed to isolate the affected teeth, to protect the surrounding soft tissue and ensure a clean and dry working field. Subsequently, ICON-etch gel was applied onto the affected tooth surface using the provided applicator tip for 2 min. After the first round of etching, the brown discoloration appeared to be deeper beyond the enamel surface [Figure 3]; hence, the enamel microabrasion technique was considered. | Figure 3: Application of rubber dam isolation and initial application of ICON etchant
Click here to view |
Air microabrasion was attempted to specifically target the superficial enamel layer of the well-demarcated lesion as an alternative to the conventional chemomechanical abrasion as described by Croll[10] [Figure 4]. Finally, to increase the Delta-E value of the tooth, the lesions were bleached with Opalescent (35% carbamide peroxide) for 45 min, as per the manufacturer's instruction [Figure 5], and thoroughly rinsed off with water for 1 min and dried with compressed air for 30 s.
When the brown discoloration was resolved and became more homogenous with the surrounding tooth, ICON etchant was reapplied for 30 s and washed off [Figure 6]. Application of ethanol (ICON Dry) on the etched surface allowed for evaluation of the general translucencies and homogeneity of the affected enamel. Once the results were acceptable by both the patient and the clinician, low-viscosity ICON infiltrant was added and left to settle for 3 min to allow deep penetration into the lesion. Excess resin was gently removed with cotton pellets and gentle flossing followed by light-cured polymerization for 60 s. To seal up superficial enamel porosities, infiltrant was reapplied for another minute and final light cure polymerization was done. Finally, polishing was done using Sof-Lex XT fine disc and Prima Gloss extra-fine composite polishing paste with a slow-speed handpiece (4000 rpm). At the end of the treatment, a TSIF score of 1 was achieved, and the patient was pleased with the results [Figure 7] and [Figure 8]. No postoperative sensitivity was reported after treatment.
At 1-year recall, apart from minimal extrinsic stains present interproximally, clinical examination and esthetic analysis showed acceptable harmonisation of infiltrated resin with the surrounding enamel and colour stability with time [Figure 9]. The patient reported no adverse events following infiltration. The patient also reported no adverse events following infiltration. Therefore, the effort to mask the discoloured lesions with a combination of microabrasion, bleaching and resin infiltration was successful and maintained clinical stability, with no significant colour alterations and biological effects at the 1-year recall.
Discussion | |  |
The objective of managing of discolored lesions is to achieve an acceptable esthetic outcome in the most conservative manner. Conservative treatment options like microabrasion, bleaching, and resin infiltration can produce dramatic improvements, as opposed to using of more invasive procedures available to manage severe fluorosis and enamel hypoplasia.[18],[19],[20],[28],[29] Increasing number of clinical reports have suggested various minimally invasive interventions such as bleaching, enamel microabrasion, and resin infiltration in combination. These reports, however, differ in the treatment sequence in which these interventions were used.[29],[30],[31],[32] Furthermore, enamel microabrasion, bleaching, or resin infiltration when done individually is limited in efficacy when dealing with varying severity of fluorosis and can yield unpredictable outcomes.[25]
Resin infiltration is also more effective in color-masking white spot lesions on enamel,[33] which was not so particularly in this case. The infiltrant is a light-polymerized material with low viscosity and high surface tension,[34] which allows rapid penetration into the capillary structures of the enamel. The ability of resin to mask enamel lesions is based on the changes in light scattering when the enamel microporosities are infiltrated. However, as the mineralized surface layer can hinder the penetration of resin into the lesion,[35],[36] this technique requires removal of the surface layer. Another advantage of this technique is that resin can seal the enamel microporosities and is capable of mechanically strengthening the demineralized tissue.[23] Although this method might demonstrate an immediate masking effect of enamel lesions, there are still concerns regarding color stability and clinical longevity due to aging and staining.[37]
Correct diagnosis and understanding the advantages and limitations of each technique available are critical during the treatment planning phase to produce a desirable outcome.[27] This patient was diagnosed according to the TSIF 4 and the depth of the lesion was initially trialed with the etch-gel and was evaluated to be inadequate for resin infiltration technique alone.
Microabrasion, a chemomechanical method to remove superficial stains, typically consists of blending an abrasive acid material into a firm paste.[38] This is manually applied with a rubber cup at low speeds to dissolve minerals and remove thin layers of enamel. However, in this case, air microabrasion was used to target the well-demarcated brown lesions. The effect of microabrasion can result in enamel loss ranging between 25 and 200 mm, which is clinically acceptable.[39] However, there lacks consensus regarding the maximum number of microabrasive cycles that can be done without causing excessive removal of tooth enamel. Moreover, this technique remains ineffective if the depth of the lesion is beyond that achieved by microabrasion and resin infiltration.[40]
Besides the depth of the lesion, another challenge faced in this particular patient was the value of the brown lesion being remarkably different from the surrounding enamel. A combination technique involving resin infiltration and bleaching showed comparable esthetic outcomes as resin infiltration with custom etching cycles, but this was applicable for mild fluorosis cases.[41] Shanbhag et al. also found that bleaching with 35% H2O2 resulted greater improvements of tooth shade in moderate fluorosis as compared to milder cases.[42] Other studies have also recommended the bleaching option if the discoloration cannot be improved by microabrasion alone,[43] or if the color of dentine can be seen through the enamel, which makes the teeth appear yellower.[44],[45] In vitro studies have shown that the extent of polymerization of resins are reduced immediately after bleaching.[46],[47] However, the inhibition of polymerization can be negated if the polymerization procedure is done at least 14 days after tooth whitening,[48],[49] through extensive rinsing of the tooth,[50] surface treatment with potent antioxidants,[51] or prolonged polymerization cycles.[48],[49] In this case, additional care was taken to extend the polymerization intervals to 60 s to counteract the inhibition of polymerization caused by whitening.
Numerous studies and case reports have demonstrated successful outcomes with the use of infiltrating resin as an effective minimally invasive approach for the management of interproximal lesions,[52] as well as esthetic treatment for developmental defects and white spot lesions,[33] evaluated up to 4 years.[53],[54] Despite yielding an instant esthetic result after clinical application, the use of ICON or other resin-based restoration materials may limit the esthetic longevity due to aging of the resin matrix.[55] Fortunately, this clinical case yielded good esthetic results instantly after clinical application and displayed acceptable clinical stability even after 12 months. Although in vitro studies have suggested the susceptibility of staining and color change of resin-based restorative materials being related to certain diets,[56] more randomized controlled long-term in vivo studies are needed to determine the color stability and durability of resin infiltration with combination approaches.
Conclusion | |  |
The combination approach of enamel microabrasion, bleaching, and resin infiltration techniques can be used in the management of more severe types of intrinsic tooth discoloration. In this case, a positive esthetic outcome was achieved with a less invasive approach as compared to conventional restorative techniques. it is imperative to realise the strengths and limitations of each technique alone, to consider adjunctive treatment options such as microabrasion and bleaching in compliment to resin infiltration, and to treat the affected subsurface enamel for better esthetic outcomes. However, more long-term data are needed to monitor the stability and predictability of combination therapy for mild–moderate brown fluorosis stains.
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.
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Correspondence Address: Dr. Lee Kong Fei Frank 9 Lower Kent Ridge Road, Level 10 Singapore
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jcd.jcd_632_20

[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9] |