The term MIH was first introduced in 2001 by Weerheijm et al., and is defined as hypomineralisation of systemic origin, presenting as demarcated, qualitative defects of enamel of one to four first permanent molars frequently associated with affected incisors.2
Epidemiological studies have shown a wide variation of between 2.8 and 40.2%.3 This variation may be due to a lack of standardisation in the tools used to record MIH, leading in many cases to an underestimation in prevalence. As a result, a recent systematic review and meta-analysis of MIH was carried out to provide a global prevalence which is estimated at 13.5%.4
Although the aetiology of MIH is not fully understood, the general consensus highlights multifactorial risk factors concerning a disturbance in the enamel development during its maturation phase, due to interruption to the formation of ameloblasts. Risk factors include pre, peri and postnatal issues, environmental conditions and early childhood illness from a variety of diseases occurring in a child’s early life which can cause a disturbance in tooth development.4
Diagnosis
Determining a definitive diagnosis of MIH can be a challenge especially in young children whose permanent dentition has not fully erupted so enamel defects will not be evident. Differential diagnosis should also be considered including amelogenesis imperfecta and dental fluorosis. Diagnosis of MIH should be made as soon as it is clinically apparent in both primary or permanent teeth. The child should be examined with clean wet teeth and if clinical signs exist, parents should be asked about any illness which occurred pre, peri or postnatally or during the first three years of life. To help standardise diagnosis, the European Academy of Paediatric Dentistry (EAPD) published a policy document on the best clinical practice for clinicians dealing with children presenting with MIH. This includes diagnostic criteria of MIH reinforcing the use of specific clinical signs and symptoms.5
EAPD Diagnostic criteria of MIH (adopted from Weerheijm et al 2003;Lygidakie et al. 2010)5
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Diagnostic feature
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Description of the defect
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Teeth involved
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One to all four permanent first molars (FPM) with enamel hypomineralisation
Simultaneously, the permanent incisors can be affected
At least one FPM has to be affected for a diagnosis of MIH
The more affected the molars, the more incisors involved and the more severe the defects
The defects may also be seen at the second primary molars, premolars, second permanent molars and the tip of the canines
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Demarcated opacities
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Clearly demarcated opacities presenting with an alteration in the translucency of the enamel
Variability in colour, size and shape
White, creamy or yellow to brownish colour
Only defects greater than 1 mm should be considered
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Post-eruptive enamel breakdown
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Severely affected enamel breaks down following tooth eruption, due to masticatory forces
Loss of the initially formed surface and variable degree of porosity of the remaining hypomineralised areas
The loss is often associated with a pre-existing demarcated opacity
Areas of exposed dentine and subsequent caries development
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Sensitivity
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Affected teeth frequently reveal sensitivity, ranging from mild response to external stimuli to spontaneous hypersensitivity
MIH molars may be difficult to anesthetise
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Atypical restorations
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The size and shape of restorations are not conforming to the typical caries picture
In molars the restorations are extended to the buccal or palatal/lingual smooth surface
An opacity can be frequently noticed at the margins of the restorations
First permanent molars and incisors with restorations having similar extensions as MIH opacities are recommended to be judged as that
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Extraction of molars
due to MIH
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Extracted teeth can be defined as having MIH when there are:
- Relevant notes in the records
- Demarcated opacities or atypical restorations on the other first molars
- Typical demarcated opacities in the incisors
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The absence of an early intervention can lead to a progressive breakdown of the tooth, increased risk of caries, possible pulpal inflammation and hypersensitivity. Associated opacities on anterior teeth are less likely to have functional problems but may result in cosmetic and psychosocial issues.5 The consequences of this can impact function, social interaction, and quality of life of the patient.
Management
MIH presents a variety of challenges for the dental team. Younger patients may demonstrate higher levels of dental anxiety which can be exacerbated due to teeth being hypersensitive to thermal and mechanical stimuli. Teeth affected by MIH can also be difficult to anaesthetise impacting the quality of restorative treatment and behavioural management. Septodont can aid patient management with our portfolio of world-leading dental pain management products, including the highest-quality pre-injection topicals, injectable anaesthetics and lower-deflection needles.
Management of MIH is largely informed by best practice clinical guidelines. The International Association of Paediatric Dentistry (IAPD) has published consensus recommendations for the management of MIH6 which includes the following steps:
1. Early diagnosis allows provision of preventive or early restorative intervention in order to avoid progressive breakdown and possible pulpal inflammation and hypersensitivity.
2. Restorations in MIH-affected teeth are associated with poorer long-term outcomes than those in unaffected teeth.
3. Long-term treatment concepts include decrease in hypersensitivity, remineralisation, sealants, resin infiltration, micro-abrasion, composites, amalgams, veneers and crowns.
- Hypersensitivity may be managed by desensitising paste and fluoride varnish.
- MIH affected enamel may have compromised bonding for sealants and composites. For adhesive restorations the cavity preparation should extend into hard tissue for better adhesion.
- Amalgam restorations show high failure rates in atypically shaped molar MIH-preparations. The need for retentive cavity preparations might aggravate existing tooth substance defects.
- Glass ionomer cements have a high failure rate in MIH but may be used for temporisation of teeth.
- For mild cases of MIH in incisors, a combination of etching, bleaching and sealing of affected areas may be a conservative approach. For more severe cases, micro-abrasion or composite may improve aesthetics. For severe cases of MIH in molars, full coverage crowns may be necessary for maintenance.
- Additional local anaesthetic procedures may be necessary to manage hypersensitivity during restorative procedures.
4. Tooth extractions of first permanent molars with or without subsequent orthodontic alignment may be considered before the eruption of the second permanent molars when more than one tooth is affected with severe MIH and pain, considering the patient’s dental age (preferably 8-9 years-old), and the occlusion and status of the neighbouring teeth.
5. Frequent recalls should be established for these patients, due to the high failure rate of the restorations in order to avoid secondary caries and more extensive breakdown.
In addition to these recommendations, some clinicians have found using tricalcium silicate, also found in Biodentine™ is a versatile treatment option to manage the symptoms and treat the effect of MIH. This is due to its dentine remineralisation and pulp healing properties alongside the ability to bulk fill. Biodentine™is also included in a recent study on the restoration of a permanent molar severely affected by MIH. This study concludes the use of bioactive materials shows promise for the restoration of molars severely affected by MIH.7
Septodont was delighted to sponsor Dr Kisby DMD lecture on 1st December 2022, at the Alliance of Molar Incisor Hypomineralization Investigation and Treatment (AMIT) Congress being held in Munich, Germany. Dr Kisby’s lecture entitled ‘The use and application of tricalcium silicates in the treatment of MIH in pediatric dentestry’ will discussed the clinical indications for the use of tricalcium silicates as a restorative base in the treatment of MIH, including its use on a pulpal exposure.
With families returning for routine examination and with the potential of 1 in 8 children being affected by MIH, why not take this opportunity to share this information with your wider dental team? The implementation of a team approach of early diagnosis and appropriate management will minimise the impact of MIH for both the patient and practice.
