What Is Molar Incisor Hypomineralisation (MIH)?
An overview of a developmental dental condition that results in weak, sensitive enamel, exploring its systemic origins and professional strategies for management.
Molar Incisor Hypomineralisation, or MIH, is a developmental condition affecting tooth enamel. It is defined as a qualitative defect, meaning the quality of the enamel is compromised, not the quantity. This condition is a recognized global dental health concern that impacts children, with a worldwide prevalence estimated to range from 2.4% to 40%.
Identifying Molar Incisor Hypomineralisation
MIH is identified by distinct visual characteristics on the hard, outer layer of the teeth known as enamel. It manifests as clearly defined patches of opacity on the tooth surface, which can be creamy-white, yellow, or brown. These opacities have well-defined borders that distinguish them from the surrounding healthy, translucent enamel.
A primary feature of MIH is post-eruptive breakdown. The affected enamel is softer and more porous than normal, making it prone to chipping and crumbling soon after the tooth emerges, which can expose the underlying dentin. The condition most commonly affects the first permanent molars and is frequently seen on the permanent incisors.
The presentation can be asymmetrical, meaning a tooth on one side of the mouth may be affected while its counterpart is not. The severity can vary, with yellow and brown opacities indicating a higher degree of porosity and a greater risk of enamel breakdown compared to white opacities.
Investigating the Origins of MIH
The precise cause of MIH is often difficult to determine, as the condition is multifactorial. It results from systemic disturbances that occur during tooth development, from late pregnancy through the first few years of a child’s life. These disturbances interfere with the normal process of enamel maturation.
Research has pointed to several potential contributing factors, including systemic health issues during early childhood like high fevers, asthma, or respiratory infections. Problems arising during the prenatal or perinatal period have also been associated with MIH, and studies suggest a possible role for genetic predisposition.
It is a misconception that poor dental hygiene or diet causes this enamel defect. MIH is not a result of inadequate tooth brushing or sugar consumption while the teeth are forming, as the defect occurs before the tooth emerges.
Common Complications and Professional Diagnosis
The defective enamel associated with MIH leads to several common dental complications. One of the most frequent issues is heightened tooth sensitivity, which can be triggered by temperature changes, sweet foods, or even the stimulus of tooth brushing.
Affected teeth are more susceptible to developing cavities at a rapid pace, and the structural weakness leads to accelerated wear and chipping. This can create challenges for dental treatments, as achieving profound local anesthesia can be difficult and the longevity of dental fillings may be reduced.
Diagnosis is performed by a dental professional through a visual examination. The dentist will look for the characteristic demarcated opacities and their distribution on the first permanent molars and incisors. A thorough patient history, including information about early childhood health, can also aid in the diagnosis.
Therapeutic Options for Affected Teeth
The management of teeth affected by MIH is tailored to the severity of the condition and the problems it causes. A primary focus is on preventive care, such as the professional application of topical fluoride varnishes or gels to strengthen the tooth surface. For molars that have not yet broken down, fissure sealants can be applied to the chewing surfaces.
When sensitivity is a major concern, dentists can apply desensitizing agents or recommend toothpastes for home use to reduce sensitivity and enhance remineralization. If the enamel has broken down or developed a cavity, restorative treatments are necessary. Materials like glass ionomer cements or composite resins are used for direct fillings.
For severely affected molars with extensive breakdown, a more durable solution is often required. Preformed crowns, such as stainless steel crowns, are frequently used to cover and protect the entire molar from further damage.
In the most severe cases, where the tooth structure is extensively compromised and cannot be reliably restored, extraction may be the recommended course of action. This decision is made in consultation with an orthodontist to plan for future space management.