Molar incisor hypomineralization (MIH) is a developmental defect characterized by a lack of mineralization in which one or more permanent first molars, and often the incisors, are affected [1]. Its etiology is unknown for certain, but it is considered multifactorial. The prevalence of MIH varies between 2% and 40% worldwide [2].
Teeth affected by MIH show enamel opacities ranging from white to brown, depending on the severity of the hypoplasia [1]. Tooth brushing or chewing forces can cause posteruptive impairment, in turn causing sensitization. In cases where the dentin is exposed, sensitivity to dental caries begins [2–4].
A diagnosis of MIH should be made when the teeth are wet after cleaning. The best age for this is when a patient is 8 years old [4].
This defect was first described by Koch [3] in 1987 and was named molar incisor hypomineralization (MIH) by Weerheijm et al. in 2003 [3, 4]. The diagnostic criteria of MIH, according to Weerheijm et.al. [4] are shown in Table 1:
Table 1
MIH diagnostic criteria as determined by Weerheijm et al.
| Demarcated 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. |
| Posteruptive Enamel Breakdown | 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 are not conform the temporary caries picture. In most cases in molars it will handle about restorations extended to the buccal or palatinal smooth surface. At the border of the restorations frequently an opacity can be noticed. In incisors a buccal restoration can be noticed not related to a trauma. |
| Extracted molar 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. It is not likely that incisors will be extracted due to MIH |
| Unerupted | The first permanent molar or the incisor to be examined are not yet erupted. |
The prisms in enamel affected by MIH are irregular and have a porous structure. The strength and hardness of the enamel decrease due to the low mineral content. These features constitute risk factors for rapid caries development and restoration failures [5]. Children affected by MIH are obliged to undergo dental treatment of their first molars nearly 10 times as often as healthy children [6].
The choice of restoration material for teeth with MIH is difficult. Although there are various treatment options, there is no consensus on the most effective treatment method. When deciding on the treatment method for a tooth with MIH, the severity of the defects, whether the affected tooth is symptomatic, the patient's dental age, and the child/parent's expectations should be considered [7]. William et al. [8], in 2006, grouped the treatment approach of affected by MIH with six steps, as shown in Table 2.
Table 2
Treatment steps in teeth with MIH determined by William et al.
| STAGES | RECOMMENDED TREATMENTS |
| Risk assessment | - Determination of possible etiological factors by medical history |
| Early diagnosis | - Radiographic evaluation of permanent molars at risk - Follow-up of these teeth during eruption |
| Removal of sensitivity and remineralization | - Topical fluoride applications |
| Prevention of caries formation and enamel loss after eruption | - Providing oral hygiene education - Reducing cariogenic and erosive diet intake - Pit and fissure sealant applications |
| Restoration and extraction | - Performing intracoronal (composite resin) or extracoronal (stainless steel crown) restorations - Evaluation of the need for orthodontic treatment after extraction |
| Patient follow-up | - Evaluation of restoration edges in terms of enamel loss after eruption - Consideration of full crown restorations as a treatment option in the long term |
There is no consensus on the best restorative option in the literature regarding the treatment of teeth with MIH. Restoration of teeth with MIH is difficult because the tissue loss is too much. Therefore, it is necessary to use materials that are resistant to chewing forces [9].
Enamel with MIH has less mineral content and quality (lower calsium and phosphorus content) and a lower modulus of hardness and elasticity than healty enamel; howewer, the protein content, carbon and carbonate concentrations are higher [10–12].
Adhesives have a lower bonding ability to the tooth surface because of the mineral deficiency caused by the higher organic content in hypomineralized tooth enamel [5]. Therefore, it is necessary to remove excess protein before using adhesives [13].
The process of removing excess protein in the enamel is called deproteinization. For this purpose, a 5% sodium hypochlorite (NaOCl) solution is frequently used. Sodium hypochlorite is a non-specific proteolytic and has an antibacterial effect. However, free radicals are released as a by-product of the collagenolytic action of NaOCl, and residual radicals on the dentin surface are thought to impair the polymerization of adhesives. Since NaOCl is a strong oxidizing agent and can affect oral soft tissues, especially in young children, it would be beneficial to use an alternative deproteinizing agent such as Papacarie gel [14]. Papacarie is a natural papain-based gel extracted from ripe green papaya fruits and leaves [15]. It has antibacterial, proteolytic and anti-inflammatory properties and has therefore been used in the chemomechanical removal of caries [16]. The proteolytic effect of Papacarie has led to its use as an effective deproteinization agent to increase enamel adhesion [17].
Papacarie gel is used for deproteinization, and in the literature review made from accessible sources, any study is found for its clinical use in teeth with MIH. This study aims to evaluate both the effectiveness of Papacarie gel as a deproteinization agent that can eliminate the disadvantages of NaOCl, which has previously been used for deproteinization, and success of the treatment as a result of the restoration of teeth with MIH with a fiber-reinforced composite resin in certain time periods with modified the United States Public Health Service Commissioned Service (USPHS) criteria [18]. Thus, it aims to create a roadmap for the most appropriate treatment of teeth with MIH.