From Volume 40, Issue 10, December 2013 | Pages 836-839
Exposure to excessive fluoride intake during the early childhood years can disrupt the normal development of enamel, resulting in dental fluorosis. This varies in severity, ranging from white opacities in mild cases to more severe black and brown discoloration or enamel pitting. This article aims to give the reader a better understanding of the aetiology, diagnosis and subsequent treatment of dental fluorosis in the paediatric patient.
Dental fluorosis is defined as a developmental disturbance of the enamel structure, caused by excessive exposure to high concentrations of fluoride. This results in a reduction of the mineral content of the enamel, and subsequently an increase in enamel porosity.
The spectrum of clinical presentation ranges from small white opaque areas of enamel to more severe discoloration, including black and brown stains. The enamel may also be pitted and rough in appearance. More severe fluorosis is less prevalent than the milder forms.
It is difficult to give an accurate figure of the prevalence of fluorosis in the United Kingdom. A review by Holloway and Ellwood found that 40% of the UK population are likely to have enamel defects and approximately half of these (20% of the population) are likely to have dental fluorosis, mainly in its mildest forms.2 Studies by the Medical Research Council, and other researchers who have found the prevalence of fluorosis of aesthetic concern, have found it to be 1% of the population in non-fluoridated areas and 3–4% in fluoridated areas.3 The 2003 UK Child Dental Health Survey found a 1% prevalence of aesthetically concerning fluorosis throughout the UK.4
The severity of the condition is related to when the overexposure occurred and for how long. For the aesthetically important maxillary permanent incisors, the risk of fluorosis is greatest if the child is exposed to excessive levels of fluoride between the ages of 20–30 months old.5
Although fluorosis may affect the primary dentition, the majority of cases are seen in the permanent dentition. Once eruption has occurred, the tooth is no longer at risk of developing fluorosis as a result of excessive fluoride exposure.
It is recommended that daily intake of fluoride should not exceed 0.05–0.07 mg F/Kg/Day. Regular intake above these levels increases the likelihood of fluorosis occurring due to chronic overexposure.6
Several sources have been identified as potential causes of overexposure to fluoride. They can be broadly separated into two categories:
Systemic fluorides include fluoridated water, table salt, milk and fluoride tablets, whilst topical fluorides include toothpastes, mouthrinses and fluoride varnishes and gels.
It is the systemic intake of a significant concentration of fluoride during the development of enamel that is attributed to the occurrence of fluorosis. The risk associated with topical fluoride is only present as a result of inadvertent swallowing resulting in systemic uptake of fluoride.
It is important that patients and parents are fully informed by their dental practitioner of the main sources of fluoride and that there is a risk whereby overexposure may result in fluorosis. It may also be highlighted that fluoride can be taken up systemically from various sources in childhood, such as infant formula foods. The risk posed from infant formula foods is only a potential problem in areas where the water supply is fluoridated; currently the majority of the UK population does not have a fluoridated water supply. A knowledge of whether the local water supply is fluoridated or not and the level of fluoridation can be used to assess a child's overall fluoride intake. A close eye should be kept on their intake until the aesthetically important incisors have erupted.
There is a need to undertake a balanced approach when assessing fluoride intake, considering the risk of aesthetic issues associated with fluorosis against the acknowledged benefits to dental health.
The education of parents and patients about sources of fluoride may help towards preventing excessive intake which may lead to fluorosis.
The principal presenting complaint for patients with fluorosis is dissatisfaction with their dental aesthetics, particularly the anterior teeth. This can be either due to discoloration, uneven colour across the enamel surface or enamel pitting. However, it should be noted that milder forms of enamel discoloration can go unnoticed by patients. In fact, one study showed that adolescents deemed the ‘pearlized’ appearance of mildly fluorosed teeth to be more attractive than non-fluorosed teeth.7
There can be numerous causes for enamel discoloration and hypoplasia. The differential diagnosis includes:
The diagnosis of fluorosis is dependent on taking a thorough history and undertaking a detailed clinical examination. It is important to ascertain the region in which the patient grew up and to determine whether the drinking water was fluoridated. Toothbrushing habits should also be explored, to determine whether the patient used a child or adult toothpaste when younger. In addition, establish the quantity of toothpaste dispensed and if the child was supervised whilst brushing. The latter is important as another potential cause of excess fluoride is habits such as swallowing toothpaste or sucking it off the toothbrush.8
When examining the dentition, it is important that adequate lighting is utilized and that the dentition is clean and dry. Distinction between fluoride induced and non-fluoride induced opacities is based on two parameters; symmetry and demarcation. Fluorosis usually presents bilaterally with diffuse opacities that are not well demarcated.9
Mild dental fluorosis is characterized by horizontal opaque and white striations that occur bilaterally and are diffuse. These striations can merge together creating the appearance of a white patch (Figure 1). More severe presentations involve the enamel being discoloured and it may even be pitted (Figure 2). It should be noted that fluorosed enamel, however severe, does not erupt into the mouth discoloured. The discoloration occurs post eruption owing to the diffusion of exogenous ions such as copper and iron into the enamel, which is abnormally porous. This porosity also results in the uptake of stains from dietary sources and other habits such as smoking.
The Thylstrup and Fejerskov Index (TFI) classifies the severity of the condition based on the biological aspects and clinical appearance of the fluorosis (Tables 1 and 2).10
| SCORE | Criteria |
|---|---|
| 0 | Normal translucency remains after prolonged air drying |
| 1 | Narrow white lines corresponding to the perikymata |
| 2 |
Smooth surfaces:
|
| 3 |
Smooth surfaces
|
| 4 |
Smooth surfaces
|
| 5 |
Smooth and occlusal surfaces
|
| 6 |
Smooth surfaces
|
| 7 |
Smooth surfaces
|
| 8 |
Smooth and occlusal surfaces
|
| 9 |
Smooth and occlusal surfaces
|
| Thylstrup and Fejerskov Index | Severity of fluorosis |
|---|---|
| TFI 1–3 | Mild |
| TFI 4–5 | Moderate |
| TFI 6–9 | Severe |
Once a diagnosis has been established, various treatment options can be discussed with the patient. Treatment of the aesthetic disturbances caused by fluorosis can range from conservative measures, such as microabrasion and vital bleaching, to more destructive measures, such as porcelain veneers.
Utilization of a classification index helps to determine the severity of the condition and subsequently suitable treatment options (Table 2).10 Mild fluorosis (TFI 1–3) can be managed with more conservative measures, such as vital bleaching and microabrasion.11 Bleaching usually involves the use of active ingredients such as carbamide peroxide (10–20%) or hydrogen peroxide (1–10%).12 At present, the UK Cosmetic Products (Safety) Regulations 2008 state that it is illegal in the UK to supply a product for the purpose of tooth whitening if that product contains or releases more than 0.1% hydrogen peroxide.13 However, an amended European cosmetics directive published in October 2011 has agreed that dentists may legally supply products for tooth whitening which release or contain up to 6% hydrogen peroxide.14 The UK Government reviewed the existing Cosmetic Products (Safety) Regulations in September 2012 to bring them in line with the European directive and states that products for tooth whitening should only be sold to dental practitioners. The first cycle of use should be undertaken by a dental practitioner or under his/her direct supervision. Tooth whitening products can then be provided for the consumer to complete the course of treatment. The new regulations also state that they are not to be used on a person under 18 years of age.15 These regulations came into force on 31st October 2012 and bleaching may now become a more viable option for the management of fluorosis in adults in coming years.
Microabrasion involves the use of an acid and pumice mixture rubbed onto the affected enamel for 5 seconds up to 10 times on each tooth. The acid can be 37% phosphoric acid (standard etching solution) or 18% hydrochloric acid. An abrasive disc could also be used in place of pumice if used gently. The aim is to remove a minimal amount of stained surface enamel. The results of microabrasion are shown in Figures 3a and b.
A combined technique of both microabrasion and vital bleaching has been suggested.16 Such an approach has been reported to achieve regularization and recovery of the original colour with minimal complications, such as sensitivity in young patients.17
Separate discoloured areas (TFI 1–3) may be treated with localized composite resin. In order to mask the discoloured area completely, the affected enamel may need to be removed with a handpiece and then composite resin placed within the defect. Alternatively, opaque base layers are available in many commercial aesthetic composite kits. A combination of both microabrasion and composite resin veneers may also be considered as a treatment option for cases of fluorosis with a TFI greater than or equal to 5.
For more severe cases (TFI 8–9), porcelain veneers may be considered as an option in the adult patient. They are not suitable in the paediatric patient owing to an alteration in the position of the gingival margin with physiological growth. Immature incisors also have large pulp chambers and the destructive preparation for a porcelain veneer may result in a loss of pulp vitality in the paediatric patient.
Whilst dental fluorosis predominantly poses an aesthetic issue, it is important to appreciate that research has shown that children diagnosed with dental fluorosis present with significantly less dental decay compared to their counterparts.7
However, in cases where a clinical diagnosis of fluorosis is suspected, clinicians must be able to take a relevant history to ascertain the likely causes of excessive fluoride exposure, and to establish a definitive diagnosis. Once this has been achieved, utilization of the appropriate indices to determine suitable treatment options is necessary. Treatment needs will vary as patient expectations and aesthetic concerns differ, based on subjective variations from one individual to another.
