A form of enamel abnormalities affecting the first molar and permanent incisors

1. MOLAR INCISOR
HYPOMINERALIZATION

2. OUTLINE
• Introduction
• Epidemiology
• Aetiology
• Diagnosis
• Clinical Features/ Problems
• Differential Diagnosis
• Treatment
• Conclusion
• References

3. INTRODUCTION
• In human body dental enamel is found to be the hardest tissue
comprising 98% mineral and <2% organic matrix and water
• Dental enamel is sensitive to environmental disturbances during
development (Amelogenesis); because of its nonremodeling nature,
it results in permanent variations of tooth enamel
• Tooth hypoplasia is a defect in quality and quantity of tooth structure
due to developmental origin.

4. INTRODUCTION CONTD.
• Molar incisor hypomineralization (MIH) is a specific form of tooth
hypoplasia. It is a common developmental dental condition that
presents in childhood.
• The term molar-incisor hypomineralisation (MIH) was first
introduced in 2001 by Weerheijm et al.
• It was defined as ‘hypomineralisation of systemic origin,
presenting as demarcated, qualitative defects of enamel of one to

5. INTRODUCTION CONTD.
• four first permanent molars (FPMs) frequently associated with
affected incisors.’
• In 2003, MIH was further described as a developmental, qualitative
enamel defect caused by reduced mineralization and inorganic
enamel components which leads to enamel discolouration and
fractures of the affected teeth.

6. INTRODUCTION CONTD.
• It is characterized by Well demarcated areas of opacities of the
enamel that varies from white to brownish colour which may affect
one or more first permanent molars
• It was reported in the past as:
• Internal enamel hypoplasia
• Idiopathic enamel opacities of permanent first molars.
• Non-endemic mottling of enamel of permanent first molars

7. INTRODUCTION CONTD.
• Non-fluoride enamel hypomineralization of permanent first molars.
• Cheese molars.
• A similar condition that shows hypomineralization of permanent first
molars alone with non-involvement of permanent incisors is termed as
molar hypoplasia (MH).
• It is seen that MIH and MH form part of an MIH spectrum, where MIH
is a more severe form of the condition than MH.

8. INTRODUCTION CONTD.
• Another condition that has been noticed is deciduous molar
hypomineralization (DMH), presenting itself as hypoplasia of
deciduous molars (DH).
• Hypoplasia of deciduous molar and DMH share a common
etiology and hence presence of DMH in deciduous dentition can be
used to predict MIH in the permanent dentition

9. EPIDEMIOLOGY
• Epidemiological studies from different parts of the world show a
wide variation in the prevalence of MIH which ranges between 2.8
to 40.2%. (Ghanim et al. 2017)
• This variation may be due to previous lack of standardized tools to
record MIH leading to underestimation of the prevalence.
• However, recent meta-analyses suggest that MIH affects around
13%-14% of the world’s children.

10. EPIDEMIOLOGY CONTD.
• Currently, it is estimated that this condition affects one in six children
worldwide. (Hubbard 2018)
• The prevalence of incisor hypomineralisation is 11%
• Prevalence in Nigeria among 8-10 years old in ile-ife is 17.6%
(Oyedele et al. 2015).
• Study in ile-ife, Nigeria among same age group by Temilola et al.
2015 puts it at 9.7%

11. EPIDEMIOLOGY CONTD.
• There is no sex predilection for MIH.

12. Different studies and prevalence rates in various
populations
Study Population Prevalence
Kukleva et al (2008) Plovdiv, Bulgaria 3.58% (2.43–7.84%)
Mahoney and Morrison
(2009
Wellington, New Zealand 14.9%
Biondi et al (2011) Buenos Aires 15.9% (13.8–18.2%)
Balmer et al (2012) Northern England 15.9% (14.5–17.1%)
Parikh et al (2012) Gujarat, India 9.2%

13. AETIOLOGY
• The causative mechanism of MIH is still unclear,
• but the clinical presentation of localised and asymmetrical lesions
suggests a systemic origin with the disruption in the amelogenesis
process most probably occurring in the early maturation stage or
even earlier at the late secretory phase.
• If an unbalance occurs during the secretion phase (ENAMEL
MATRIX FORMATION), the enamel defect is called hypoplasia.

14. AETIOLOGY CONTD.
• If it occurs during the maturation phase (ENAMEL
MINERALIZATION), it is called hypomineralization
• In general, the condition seems to be multifactorial and systemic
factors such as acute or chronic illnesses or exposure to
environmental pollutants during the last gestational trimester and
first three years of life have been suggested as causative or
contributing factors.

15. AETIOLOGY CONTD.
• Risk factors associated to MIH
include:
• Asthma,
• Pneumonia,
• URTI
• Otitis media
• Antibiotics (Amoxicillin)
• Dioxins in mother’s milk
• Tonsillitis and tonsillectomy
• Exanthamatous fevers of
childhood
• Polychlorinated biphenyl
• Birth and neonatal factors

16. AETIOLOGY CONTD.
• Acute or chronic childhood
illness/treatment,
• fluoride or breastfeeding
• Hypoxia,
• Hypocalcemia,

17. Exposure
to environmental
contaminants
medically compromised
children.
common childhood
illnesses
exposure to fluoride
Multifactorial

18. Relation of Molar Incisor Hypomineralization
with Other Conditions

19. Molar incisor hypomineralization and asthma
• Asthma medications, mostly applied by metered-dose inhalers
(MDIs), are acidic in nature and reduce salivary function; they
create a favorable environment for cariogenic bacteria (Mazzoleni
et al. 2008).
• Chuang et al., 2018 confirmed the association between asthma and
dental caries and assessed that asthma increased the risk of caries
by two factor.

20. • Asthma was regarded as a risk factor for the development of MIH in the
first few years of life only (Allazzam et al., 2014).
• According to Claudia Flexeder et al., 2019, a significant positive
association was found for asthmatic adolescents who did not take MDI
medication with higher MIH/t values compared to non-asthmatics.
• According to Wogelius et al., 2020, no association was found between
the use of inhaled asthma medication and the prevalence of MIH.

21. Molar Incisor Hypomineralization and
Antibiotics
• Positive association was observed between MIH and antibiotics
(penicillin use) and ENT disorders.
• Mulic et al. studied children with MIH and found that the use of
penicillin due to adenoid infections in the first 5 years was
associated with a higher prevalence of enamel lesions.

22. • Furthermore, Laisi et al. stated that an altered pattern of
amelogenesis may interfere with the process of enamel
mineralization and that the early use of amoxicillin is one of the
main causative factors of MIH.

23. Molar Incisor Hypomineralization and
Cesarean Section Delivery
• Newborns delivered vaginally had increased risk of respiratory
illnesses such as hypoxia than those delivered by elective cesarean
section.
• Further, the commonly used spinal anesthesia for cesarean section
has a frequent complication of maternal hypotension that can be
associated with severe nausea or vomiting which occasionally
produces infant hypoxia.

24. • Hypoxia at birth and/or being born by cesarean delivery had a
statistically significant association with the presence of MIH.

25. Molar Incisor Hypomineralization and Dental
Caries
• Developmental defects of the enamel are due to faulty enamel
formation, which makes the enamel more susceptible to attack by
acids and therefore to dental caries.
• The defective enamel provides an ideal environment for plaque
adhesion and colonization by cariogenic bacteria, enabling lesions
to progress rapidly.

26. • Elfrink et al. observed that the mean density of hydroxyapatite in
opacities in the yellow to brown color range is 20%–22% lower
than in sound enamel.
• Pitiphat et al., 2020 found that caries is 10 times more frequent in
teeth with posteruptive breakdown than teeth having only
opacities.

27. Molar Incisor Hypomineralization and Vitamin D
• As ameloblasts and odontoblasts are target cells for Vitamin D or
its metabolites, they play key roles in enamel and dentin formation
(Berdal et al., 1995; Berdal et al., 2000).
• Therefore, it is plausible that Vitamin D deficiency is linked to
developmental disorders in the enamel (e.g., Vitamin D-dependent
rickets).

28. Molar Incisor Hypomineralization and Vitamin
D Contd.
• The total Vitamin D serum concentration was determined by Roche's
Vitamin D Laboratory Test using the fully automated modular
system.
• Lower Vitamin D serum concentration was associated with a higher
probability for MIH and caries and vice versa; it can be argued that
elevated serum 25(OH) D concentrations levels were related to
better oral health outcomes.

29. DIAGNOSIS

30. • The ideal time to diagnose MIH
is as soon as it is clinically
apparent either in primary or
permanent dentition.
• The examination should be
performed on clean wet teeth.
• Weerhrijm et al. 2003 developed
diagnostic criteria for MIH:
• Absence or presence of
demarcated opacities;
• Posteruptive enamel breakdown;
• Atypical restorations;
• Extraction of molars due to MIH;
• Failure of eruption of a molar or
an incisor.

31. Diagnostic criteria for MIH by (Weerheijm et al.
2003)
CRITERIA DEFINITION
opacity A demarcated defect involving an alteration in the translucency of the enamel, variable in degree.
The defective enamel is of normal thickness with a smooth surface and can be white, yellow or
brown in colour.
PEB A defect that indicates deficiency of the surface after eruption of the tooth. Loss of initially formed
surface enamel after tooth eruption. The loss is often associated with a pre-existing demarcated
opacity.
Atypical
restoration
The size and shape of restoration do not conform to typical restorative characteristics.In most cases
restorations extendeds to the buccal or palatinal smooth surface of a molar tooth. In incisors, a labial
restoration can be noticed not related to a trauma.
Extraction
due to MIH
Absence of a first permanent molar should be related to the other teeth of the dentition. Suspected
for extraction due to MIH are: opacities or atypical restorations in the other first permanent molars
combined with absence of a first permanent molar. Also the absence of first permanent molars in a
sound dentition in combination with demarcated opacities on the incisors is suspected for MIH
Unerupted The first permanent molar or the incisor to be examined are not yeterupted.

32. CLASSIFICATION
• Mathu-Muju and Wright, 2006 classified MIH into three severity
levels based on the diagnostic criteria,
• Mild MIH:
• The demarcated opacities located at non-stress bearing areas,
• No caries associated with the affected enamel,
• No hypersensitivity and
• Incisor involvement is usually mild if present

34. CLASSIFICATION CONTD.
• Moderate MIH:
• The demarcated opacities are present on molars and incisors,
• The post-eruptive enamel breakdown limited to one or two
surfaces without cuspal involvement,
• Atypical restorations can be needed
• Normal dental sensitivity

36. CLASSIFICATION CONTD.
• Severe MIH:
• Post-eruptive enamel breakdown,
• Crown destruction progressing to pupal involvement.
• Caries associated with affected enamel,
• History of dental sensitivity and aesthetic concerns.

38. CLASSIFICATION CONTD.
• However, Weerheijm et al., 2001 had classified MIH as:
• Mild – Color change of the smooth surface without enamel
defects
• Moderate – Loss of enamel without dentine involvement
• Severe – Dentine involvement, atypical restorations, and teeth
extracted because of severe lesions.

39. CLINICAL
FEATURES/PROBLEMS IN
MIH

40. • Clear demarcation between the affected and sound enamel
• The hypomineralized enamel will be softly porous and has a
discolored chalky appearance
• Demarcated white/yellow/brown opacities usually limited to incisal
or cuspal one third, rarely involving cervical one third. Defects that
are <1 mm are not reported under MIH
• In molars, posteruptive enamel breakdown is common due to
occlusal loading.

41. • Rapid caries progression- because of the porous and friable enamel
structure.
• Adhesion of restoration material is poor.
• Anaesthetic difficulties: A combination of hypersensitivity and
rapidly progressing caries causes chronic inflammation of the pulp,
preventing effective local anesthesia
• Esthetic problems in anterior teeth..

42. • Tooth sensitivity, which might lead to poor oral hygiene and
therefore, caries susceptibility increases
• Behavioural management problems due to dental fear and anxiety
which is related to the pain experienced by the patients during
multiple treatment appointments

43. DIFFERENTIAL DIAGNOSIS

44. • Fluorosis: Associated with history of fluoride ingestion during
enamel development.
• Clinically, fluorosis presents as diffuse, linear, patchy or confluent
white opacities without a clear boundary.
• It affects teeth in a symmetrical, bilateral pattern unlike MIH
which is asymmetrical.
• Teeth affected by fluorosis are caries-resistant while in MIH they
are caries-prone

45. • Enamel hypoplasia:
• This is a quantitative defect with reduced enamel thickness.
• The borders of hypoplastic enamel lesions are mostly regular and
smooth, indicating developmental and pre-eruptive lack of
enamel.
• The margins in MIH with post-eruptive enamel breakdown are
sharp and irregular due to post-eruptive shearing of weakened
enamel.

46. • Amelogenesis imperfecta:
• This is a genetic condition which results in enamel that is
hypoplastic, hypomature, or hypomineralised.
• In this condition, all teeth in both dentitions are affected and a
familial history is often present.

47. • White spot lesion:
• This is the earliest clinical sign of caries.
• The lesions appear chalkier, matt or more opaque than the
adjacent sound enamel.
• They can be distinguished from MIH because they occur in
areas of plaque stagnation, such as the cervical margin of the
tooth.

48. • Traumatic hypomineralisation
• This is associated with a history of dental trauma to the primary
predecessor tooth.
• Periapical infection of the primary tooth can disturb
mineralization of the underlying tooth germ.
• It has a wide variety of clinical presentations differing in shape,
outline, localization and colour.
• It is often limited to one tooth and asymmetrical.

49. MANAGEMENT OF MIH
• Identification of patients at risk of MIH and early diagnosis can
lead to more effective and conservative management.
• There are currently no guidelines available for the management of
MIH, however, the EAPD published a consensus paper in 2010 as
‘best clinical practice guidance for clinicians dealing with MIH.

50. Treatment options for molars
• It has been reported that these teeth have five to ten times more
dental treatment need than molars without MIH.
• When managing these teeth, the first clinical consideration is
whether to restore or extract.
• This depends on factors such as:
• Child’s age;
• Severity of MIH;

51. Treatment options for molars Contd.
• Pulp involvement;
• Restorability of the tooth/teeth;
• Expected long-term prognosis; and
• Long-term treatment cost

52. Resin infiltration
• This technique uses a very low viscosity resin which is capable of
penetrating demineralized enamel.
• Also known as erosion-infiltration,
• Icon system by DMG (Hamburg, Germany) is the only material
available for this procedure.
• Its manufacturer recommends this material to treat incipient caries
and/or carious white spot lesions reaching up to the outer third of
dentine.

53. Resin infiltration Contd.
• The Icon system consists of Icon-Etch (15% hydrochloric acid),
Icon-Dry (99% ethanol), and Icon-Infiltrant (Methacrylate-based
resin).
• The hydrochloric acid is used to eliminate the relatively intact
surface layer and open access to the body of the lesion, then the
fluid resin is infiltrated into the broad channels of communication

54. Resin infiltration Contd.
• The main disadvantages of RC are the following:
• Shrinkage due to the extent of the restoration,
• Reduced strength due to impaired bond strength,
• Microleakage,
• Occlusal wear, and
• Restoration durability

55. Restorations
• When restoring hypomineralised teeth, dentists frequently face
difficulty in defining the cavity margins.
• Cavity design plays a critical role, as defective enamel remnants
compromise the end result.
• It is recommended that the cavity design should involve removal of
all the porous but not necessarily discoloured enamel, until
resistance to the bur or to the probe is achieved.

56. Restorations Contd.
• Glass ionomer cement (GIC) or resin modified GIC restorations
can be considered only as an intermediate approach until definitive
restoration is placed.
• Resin composite is the material of choice and recommended for one
to three surface restorations and the pre-treatment with 5.25%
sodium hypochlorite can improve the bond strength.
• Amalgam should be avoided due to atypically shaped cavities in

57. Restorations Contd.
• MIH molars so further breakdown often occurs at the margins,
• It is a non-adhesive so does not restore the strength of the tooth,
and is a poor insulator

58. Full or partial coverage
• Preformed metal crowns (PMCs) can be used successfully in
severely damaged MIH molars with high long-term survival rates.
• PMCs can prevent further post-eruptive enamel breakdown, manage
sensitivity, are not expensive, can establish correct interproximal
and occlusal contacts, require no/little tooth preparation, and can be
done in single visit.
•

59. Full or partial coverage Contd.
• Non-precious metal, gold or tooth-coloured indirect onlays can be
used in older children but the procedure is time-consuming,
technique-sensitive and expensive.
• Preformed malleable composite temporary crowns that come in
different sizes (Protemp Crown Temporisation Material by 3M
ESPE) can offer an aesthetic option.

60. Extraction of severely affected molars
• For severely affected FPMs with poor prognosis, extraction might
be considered at the dental age of eight to ten years.
• This will give the second permanent molars (SPM) an opportunity
to drift into the FPM position.
• The chance of ideal positioning is 94% for upper Second
permanent molars (SPMs) and 66% for lower SPMs after the
extraction of FPMs.

61. Extraction of severely affected molars
Contd.
• Before a decision to extract the molars is made, full dental
assessment should be carried out to check for the presence,
position and normal formation of the developing permanent
dentition to ensure favourable orthodontic conditions.

62. TREATMENT OPTIONS FOR ANTERIORS
• Aesthetic concerns are common in patients with MIH with incisor
involvement.
• In young patients, these teeth should be treated in a conservative
approach as they have immature anterior teeth with large and
sensitive pulps.
• Therefore, it is preferred to postpone the aesthetic treatment as the
enamel opacities often become less profound in the long term.

63. TREATMENT OPTIONS FOR ANTERIORS
• In general, the yellow-whitish defects are less severe than the
yellow-brownish defects and the defects on the incisors are milder
than those on molars,
• however, the defects on the incisal edge tend to undergo post-
eruptive breakdown more than those within the labial surface, and
are thus clinically more difficult to manage.

64. • The following are some possible treatment options for anterior
teeth with MIH, which could be used alone or in a combination of
methods to achieve better aesthetic results.

65. Microabrasion
• This involves the removal of a small amount of surface enamel
(no more than 100 μm [0.1 mm]) through abrasion and erosion
using 18% hydrochloric acid or 37.5% phosphoric acid with
pumice.
• The process abrades the surface enamel while also polishing it
which leads to changes in optical properties and this may improve
the aesthetics.

66. Microabrasion Contd.
• Microabrasion is indicated when the discolouration is limited to
the outer surface of enamel and it is more effective at eliminating
brown mottling

67. Tooth bleaching
• The aim is to camouflage white opacities by increasing the overall
brightness of the teeth.
• This option is indicated for adolescents.
• The possible side-effects of bleaching are: sensitivity, mucosal
irritation, and enamel surface alterations.
• Bleaching agent alone is not recommended on a hypomineralized
tooth because of mineral changes caused by peroxides causing an

68. Tooth bleaching Contd.
increase in carbon content and a decrease in calcium and phosphate
content.
• During a bleaching treatment, peroxides initiate oxide–reduction
reaction that may lead to dissolution of both organic and inorganic
matrices.
• Stefano Mastroberardino et al 2012 combined the use of CPP-
ACP Tooth Mousse and bleaching gel.

69. Tooth bleaching Contd.
• The CPP-ACP tooth mousse will remineralize the MIH opacities
during the bleaching process without interfering with bleaching
effect and will protect the tooth structure.
• The combined use of hydrogen peroxide and CPP-ACP could be
done with a ratio range from 1:6 to 3:4.

70. Etch-bleach-seal technique
• This technique was suggested by Wright to remove yellow-brown
stains.
• The affected tooth should be etched first with 37% phosphoric acid
for 60 seconds, followed by continuous application of 5% sodium
hypochlorite as the bleaching agent for five to ten minutes.
• Then the tooth should be re-etched and covered with a protective
layer such as clear fissure sealant or composite bonding agent.

71. Etch-bleach-seal technique Contd.
• With this technique the yellow-brown stains can be eliminated
leaving a white mottled appearance which is more aesthetically
acceptable.

72. Composite restorations or veneers
• Composite restorations involve removal of defective enamel and
composite resin build-up using opaque resins to avoid excessive
enamel reduction.
• While composite veneers could be a more conservative approach as
it can be achieved with no tooth preparation that is, no removal of
even defective enamel.
• These options could be indicated for large enamel defects that

73. Composite restorations or veneers Contd.
require treatment due to exposed dentine or chipped enamel.
• The bond strength to hypomineralised enamel can be improved
significantly by pre-treatment with 5.25% sodium hypochlorite for
one minute after etching.
• The composite resins are susceptible to discolouration, wear and
marginal fractures, therefore, long-term maintenance is required.

74. Porcelain veneers
• These are indicated for patients aged 18 years and above when the
gingival margin has matured.
• It can be an option when the other techniques failed to produce
satisfactory results.

75. CONCLUSION

76. • Children with poor general health in early childhood or with
hypomineralised second primary molars should be considered at risk
of MIH.
• Therefore, they should be monitored more frequently during eruption
of the FPMs.
• Management of these teeth should consider their long-term prognosis,
as well as management of the presenting features such as pain.

77. • Aesthetic management of MIH incisors should be as conservative
as possible and the extent of treatment depends on the patient’s age,
aesthetic concern and lesion severity.
• The remineralisation and resin infltration techniques are possible
effective conservative approaches in managing MIH teeth but these
treatment modalities require further investigation to introduce the
best technique/protocol in using them for MIH cases.

78. • Since MIH is considered common, it should be diagnosed and
managed in primary care wherever possible.

79. THANK YOU

80. REFERENCES
• Shafer WG, Hine MK, Levy BM, editors. Developmental disturbances of oral
and paraoral structures. In: Textbook of oral pathology. 4th ed. Philadelphia
(PA): WB Saunders; 1983. p. 2-85.
• Weerheijm K L, Jalevik B, Alaluusua S. Molar-incisor hypomineralisation.
Caries Res 2001; 35: 390–391.
• Weerheijm KL, Duggal M, Mejàre I, Papagiannoulis L, Koch G, Martens LC,
Hallonsten AL. Judgement criteria for molar incisor hypomineralisation (MIH)
in epidemiologic studies: a summary of the European meeting on MIH held in
Athens, 2003. Eur J Paediatr Dent 2003 Sep;4(3):110-113.
• Weerheijm K L, Duggal M, Mejare I et al. Judgement criteria for molar incisor
hypomineralisation (MIH) in epidemiologic studies: a summary of the
European meeting on MIH held in Athens, 2003. Eur J Paediatr Dent 2003; 4:
110–113

81. REFERENCES
• Weerheijm KL. Molar incisor hypomineralisation (MIH). Eur J Paediatr Dent
2003 Sep;4(3):114-120.
• Gotler M, Ratson T. Molar incisor hypomineralization (MIH) – a literature
review. Refuat Hapeh Vehashinayim 2010 Apr;27(2):10-18.
• Ghanim A, Silva M J, Elfrink M E C et al. Molar incisor hypomineralisation
(MIH) training manual for clinical feld surveys and practice. Eur Arch
Paediatr Dent 2017; 18: 225–242.
• Elfrink M E, Ghanim A, Manton D J, Weerheijm K L. Standardised studies
on Molar Incisor Hypomineralisation (MIH) and Hypomineralised Second
Primary Molars (HSPM): a need. Eur Arch Paediatr Dent 2015; 16: 247–255.
• Jalevik B. Prevalence and Diagnosis of MolarIncisorHypomineralisation
(MIH): A systematic review. Eur Arch Paediatr Dent 2010; 11: 59–64.

82. REFERENCES
• Hubbard M J. Molar hypomineralization: What is the US
experience? J Am Dent Assoc 2018; 149: 329–330