MIH Molar Incisor Hypomineralization Dr S E Jabbarifar 2010 Lecturer in Paediatric Dentistry (Paediatric Dentistry)

MIH Introduction Clinical Presentation Prevalence Aetiology Treatment

MIH Molar-Incisor hypomineralization is defined as a hypomineralization of systemic origin that affects one to all of the first permanent molars and is often associated with affected permanent incisors (Weerheijm et al., 2001)

MIH MIH molars can create serious problems for the dentist as well as for the child affected

MIH Dentists Child rapid caries development inability to anaesthetize the MIH molar unpredictable behaviour of apparently intact opacities restoration difficulties Child experience pain and sensitivity (even when the enamel is intact) Pain during brushing appearance of their incisor teeth

Clinical Features Primary teeth are not affected one, two, three or four permanent first molars affected white/yellow/brown opacities well demarcated compared to normal enamel

Clinical Features usually presents on the buccal or occlusal surfaces of the molars and incisors asymmetrical defects the risk of defects to the incisors appears to increase when more first permanent molars have been affected

Clinical Features the affected molars are sensitive to cold and appear to be more difficult to anaesthetise the lesions on the incisors are usually not as extensive as those in the molars and present mainly a cosmetic problem the remaining permanent dentition is usually not affected

Diagnosis It is important to diagnose MIH, delineating it from other developmental disturbances of enamel

Diagnosis Diagnostic criteria to establish the presence of MIH include: the presence of a demarcated opacity (defect altering the translucency of the enamel) posteruptive enamel breakdown (loss of surface enamel after tooth eruption, usually associated with a pre-existing opacity) atypical restorations (frequently extend to the buccal or palatal smooth surfaces reflecting the distribution of hypoplastic enamel)

Diagnosis Mild MIH Demarcated opacities are in nonstress-bearing areas of the molar No enamel loss from fracturing is present in opaque areas There is no history of dental hypersensitivity There are no caries associated with the affected enamel Incisor involvement is usually mild if present

Diagnosis Moderate MIH Atypical restorations can be present Demarcated opacities are present on occlusal/incisal third of teeth without posteruptive enamel breakdown Posteruptive enamel breakdown/caries are limited to 1 or 2 surfaces without cuspal involvement Dental sensitivity is generally reported as normal

Diagnosis Severe MIH Posteruptive enamel breakdown is present There is a history of dental sensitivity Caries is associated with the affected enamel Crown destruction can advance to pulpal involvement Defective atypical restoration Aesthetic concerns are expressed by the patient or parent

Differential diagnosis MIH can sometimes be confused with fluorosis or amelogenesis imperfecta

Differential diagnosis It can be differentiated from fluorosis as its opacities are demarcated, unlike the diffuse opacities that are typical of fluorosis fluorosis is caries resistant and MIH is caries prone fluorosis can be related to a period in which the fluoride intake was too high

Differential diagnosis Choosing between amelogenesis imperfecta (AI) and MIH: only in very severe MIH cases, the molars are equally affected and mimic the appearance of AI In MIH, the appearance of the defects will be more asymmetrical In AI, the molars may also appear taurodont on radiograph There is often a family history

Prevalence The prevalence figures range from 3.6–25% and seem to differ between countries The number of hypomineralized first permanent molars in an individual can vary from one to four The frequency of MIH molars was not evenly divided among children

Aetiology Amelogenesis is a highly regulated process The asymmetrical occurrence of MIH suggests that the ameloblasts are affected at a very specific stage in their development Children with poor health during the first 3 years of life are more likely to be at increased risk for MIH

Aetiology Ameloblast cells are irreversibly damaged Clinically these appear as yellow or yellow/brown opacities These opacities are more porous Ameloblasts have the potential to recover after the disturbance These defects appear creamy yellow or whitish cream demarcated opacities

Aetiology Various causes of MIH have been implicated: Environmental conditions Respiratory tract infections Perinatal complications Dioxins Oxygen starvation and low birth weight Calcium and phosphate metabolic disorders Childhood diseases Antibiotics Prolonged breast feeding the aetiology of MIH still remains unclear

Restoration Children with MIH may have extensive treatment needs By the age of nine, children with MIH were treated ten times as often as children without such molars MIH children display more dental fear and anxiety Children with MIH exhibited greater DMFS and dmfs

Restoration MIH molars are fragile, and caries may develop easily in these molars This is aggravated because children tend to avoid the sensitive molars when brushing In order to minimize the loss of enamel and any damage due to caries, both preventive and interceptive treatment is required

Restoration Besides normal brushing and education, prevention also includes fluoride varnish application and application of glass ionomer sealants Sometimes the sensitivity of the teeth is decreased by these applications In some cases of hypersensitivity the use of casein phosphopetide-amorphous calcium phosphate (CC-ACP) (Tooth Mousse) products have been advised as they remineralize and desensitize the tooth

Extraction Extraction combined with orthodontic treatment, should be considered as an alternative treatment, especially if the molars have a poor longterm prospect. The optimal time for extraction is indicated by the calcification of the bifurcation of the roots of the lower second permanent molar

Short-Term Treatment The immediate treatment planning needs of young children with MIH must reflect: Behavioural Preventive growth and development restorative requirements The objective is to: maintain function preserve tooth structure plan for any required orthodontic care

Partially Erupted Molars Prone to caries development and highly sensitive Applying desensitizing agent in combination with fluoride varnish applications could be of some help in decreasing sensitivity GI to cover the affected surfaces of a partially erupted molar can act as an interim method of: decreasing sensitivity reducing caries susceptibility preserving tooth structure

Mild MIH: Short-Term Treatment Prevention and maintaining the dentition Teeth should be carefully monitored applying fluoride varnish and placing sealants on the occlusal surfaces of molars where the enamel is intact and the patient does not report any sensitivity, sealants are the current treatment of choice 60-second pretreatment with 5% sodium hypochlorite (NaOCl) to remove intrinsic enamel proteins may be beneficial

Moderate MIH: Short-Term Treatment preventive measures previously outlined intervention may be required Anterior teeth with isolated demarcated opacities that are of aesthetic concern can be treated with NaOCl or other bleaching techniques, microabrasion, or resin restorations Yellow or yellow/brown spots in incisors or molars can lighten and become less noticeable with bleaching, but whitish opacities may become more prominent after applying the bleach

Moderate MIH: Short-Term Treatment For posterior teeth with enamel loss or decay limited to 1 or 2 surfaces that does not involve cuspal tooth structure, resin is the material of choice if the tooth can be adequately isolated The outline of the restoration should be made in non-hypomineralized enamel, but it can be very difficult to find out where sound enamel begins, resulting in repeated restorations due to disintegration of adjacent enamel or opacities on other spots.

Moderate MIH: Short-Term Treatment Two approaches have been described in determining the location of the cavity margin but neither is ideal Fall the visibly defective enamel is removed Only the very porous enamel is removed until good resistance is felt between the bur and the sound enamel Existing, intact restorations on molars should be carefully monitored

Available adhesive dental materials GI RMGI Compomer RBC Glass ionomers and resin-modified glass ionomers have poor wear resistance and are not recommended for placement in stress-bearing areas The enamel-adhesive interface Porous Cracks Decreased bond strength Cohesive failure

Severe MIH: Short-Term Treatment Treatment of children with severe MIH presents a tremendous challenge Early intervention is necessary to prevent PEB To minimize discomfort and decrease the likelihood of behaviour management problems, profound local analgesia is necessary Some patients may benefit from the use of nitrous oxide sedation in conjunction with local anaesthesia

Stainless-steel crowns protect the tooth against Once the molar has erupted, preformed stainless-steel crowns are the treatment of choice for severely hypoplastic molars Stainless-steel crowns protect the tooth against masticatory forces protect enamel from acid attack decrease sensitivity increase the child’s OH compliance

Long-Term Treatment Once children have a mature dentition and a more stable gingival to clinical crown height, full-coverage cast restorations should be considered to replace the interim stainless-steel crowns on molars Anterior teeth can be managed with veneers or crowns should they be indicated for severe cases of enamel defects, and where aesthetic concerns continue to be an issue

Summary Early Diagnosis High risk prevention protocol Make a decision regarding prognosis of the molars Extract if prognosis is poor or if behaviour management will be an issue

Summary Replace missing tooth structure Regular recall Use best available restorative material SSC ideal Regular recall Delay aesthetic treatment of the incisors until the child requests treatment

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