• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.598-603
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• 1998

Amelogenesis imperfecta is a group of hereditary defects of enamel unassociated with any other generalized defects. The prevalence of this condition has been estimated to range from 1 in 14,000 to 1 in 16,000, depending on the population studied. It may be differentiated into three general types : hypoplastic, hypocalcified, and hypomaturation, depending on the clinical presentation of the defects and the likely stage of enamel formation that is primarily affected. The dentin and root form are usually normal, but the enamel may lack the normal prismatic structure, being laminated throughout its thickness or at the periphery, with the result that these teeth are more resistant to decay. This case is that of an six-year-old girl brought to the pediatric dentistry department by her parents for esthetic reasons and also because of slight dental sensitivity. Clinical and radiographic examinations confirmed amelogenesis imperfecta. The author has treated with the crowning of the primary molars, using prefomed NiCr crowns and periodic fluoride application on whole dentition.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.499-504
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• 2000

Amelogenesis imperfecta is defined as a genetically determined effect affecting enamel formation and may be associated with other ectodermal or systemic disorders. It is entirely an ectodermal disturbance, since the mesodermal components of the teeth are basically normal. The presentation of diverse clinical manifestations in 1:14,000 to 1:16,000. Classification of the AI types considers mode of inheritance and clinical manifestations. The most widely accepted classification system recognize three major groups; i.e., hypoplastic(thin enamel), hypocalcified(primary mineralization defect), hypomaturation(defect in enamel maturation). The treatment is that at first, genetic counselling must be practiced, and in anterior teeth, composite resin veneer or jacket crown for esthetics, and in posterior teeth, stainlees steel crown or gold onlay.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.12 no.2
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• pp.31-38
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• 2003

Amelogenesis imperfecta patients suffered common clinical problems of poor esthetics, teeth sensitivity, and loss of occlusal vertical dimension. Amelogenesis imperfecta is a group of inherited disorders primarily affecting dental enamel. Variants of amelogenesis imperfecta generally classified hypoplastic, hypocalcified, or hypomaturation types based on the primary enamel defects. The mildest problems were found in the pitted hypoplastic type whereas the most severe problems were encountered in the hypocalcified type amelogenesis imperfecta. Management stragies include composite resin veneer and jacket crowns for anterior teeth as well as steel crowns for posterior teeth. Knowledge of the clinical features and dental complications of each variants if amelogenesis impecta helps in the diagnosis of the condition and allows institution of early preventive measures. The objective of this paper is to provide a review of the current concepts of the wide spectrum of etiological factors involved in the pathogenesis of this significance clinical entity in the primary dentition.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.562-570
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• 2008

Amelogenesis imperfecta is a group of hereditary defects of enamel, unassociated with any other generalized defects. It is classified into 14 subtypes according to different clinical and genetic features. According to its clinical features, it is classified into hypoplastic type, hypocalcified type and hypomaturation type. However, these features tend to co-exist often. Dental features associated with amelogenesis imperfecta include quantitative and qualitative enamel deficiencies, pulpal calcification, root malformations, abnormal eruption, impaction of permanent teeth, progressive resorption of root and crown, congenital missing teeth and anterior and posterior open bite occlusions. The first case patient is a 16 month-old child with discoloration of deciduous teeth. All of her deciduous and permanent dentition has shown amelogenesis imperfecta. The restorational, orthodontic and recent prosthodontic treatments have been completed. Another patient is a 9 year and 3 month-old child with amelogenesis imperfecta in both deciduous and permanent dentition. The restoration has been done and the prosthodontic treatment is planned after the completion of growth. Above cases indicate that amelogenesis imperfecta occurs both in deciduous and permanent dentition, and it requires the long term treatment and care.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.4
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• pp.467-471
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• 2010

Amelogenesis imperfecta, one of the dental genetic disease, is clinically and genetically complex disease. Amelogenesis imperfecta can be classified into three major categories according to clinical phenotype; hypoplastic, hypomaturation, and hypocalcification. Recently a novel gene, Fam83h, was identified to cause autosomal dominant hypocalcification amelogenesis imperfecta, however its functional role in the pathogenesis of enamel defect is not known yet. So this study was aimed to identify the knockdown effect of Fam83h gene on the amelogenin mRNA expression via shRNA transfection into immortalized ameloblast cell line. The result showed that the knockdown of Fam83h did not influence the amelogenin expression. Further study of the functional role of Fam83h gene should be performed to understand the complex nature of amelogenesis as well as molecular pathogenesis of amelogenesis imperfecta.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.704-709
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• 1998

Amelogenesis imperfecta represents a group of hereditary conditions that manifest enamel defects without evidence of generalized or systemic disorders. These enamel disorders are apparently heterogeneous in the basic chemical structure, resulting in a diverse presentation of clinical characteristics. The reported prevalence of amelogenesis imperfecta varies from 1 in 14,000-16,000 to 1.4 in 1,000 depending on specific population studied with the autosomal dominant hypocalcification type of amelogenesis imperfecta believed to be the least prevalent. The most widely accepted current classification system for delineating the amelogenesis imperfecta types considers the mode of inheritance and clinical manifestations. Three major groups are recognized; hypoplastic, hypocalcified, and hypomaturation types. Delineating specific types of amelogenesis imperfecta can be confusing due to the phenotypical similarity of many forms and that the most recent classification lists 14 different types. A 12 year-old female patient came to our pediatric dentistry clinic complaining of the ugly shape and color of her teeth, especially the upper front area. Although the goal of the treatment was mainly focused on the improvement of patient's esthetics, longevity of the restorations was also considered in selecting the appropriate restorative system, resin jacket crown, which can satisfy the both aspects.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.601-606
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• 2009

Amelogenesis Imperfecta (AI) is a genetic disorder which retards the development of enamel and it can be classified into three types: hypoplastic, hypomaturation, hypocalcified type. This can occur both in deciduous and permanent dentition. A 8 year 8 month old patient with a chief complaints of delayed eruption on upper anteriors, calculus deposit on lower anteriors and anterior openbite visited the clinic. Anteriors had thin layer of enamel and were very narrow. Especially lower anteriors had rough surface and were in bad shape. Teeth were very hypersensitive to thermal changes. Upper and lower first molars showed severe attrition on the occlusal surface. Radiographs also verified hypoplastic enamel in the whole dentition including the teeth in the tooth bud. The patient was diagnosed as hypoplastic AI, and is being treated at the pediathc and prosthodontic department of the Kyunghee dental university hospital. To improve the function, esthetics, hypersensitivity of the AI patients, restorations on the posteriors and the anteriors with oral hygiene instruction are necessary, Constant follow-up check is needed until full growth and after full growth, cooperative care with the other department is needed.

• International Journal of Oral Biology
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• v.34 no.1
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• pp.21-28
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• 2009

Mutations in DLX3 are associated with both autosomal dominant hypoplastic hypomaturation amelogenesis imperfecta (ADHHAI) and tricho-dento-osseous (TDO) syndrome. ADHHAI is caused by a c.561_562delCT (2bp-del DLX3) mutation whereas TDO syndrome is associated with a c.571_574delGGGG (4bp-del DLX3) mutation. However, although the causal relationships between DLX3 and an enamel phenotype have been established, the pathophysiological role of DLX3 mutations in enamel development has not yet been clarified. In our current study, we prepared expression vectors for wild type and deletion mutant DLX3 products (4bp-del DLX3, 2bp-del DLX3) and examined the effects of their overexpression on the expression of the enamel matrix proteins and proteases. Wild type DLX3 enhanced the expression of matrix metalloprotease 20 (MMP20) mRNA and protein in murine ameloblast-like cells. However, neither a 4bp-del nor 2bp-del DLX3 increased MMP20 expression. Wild type DLX3, but not the above DLX3 mutants, also increased the activity of reporters containing 1.5 kb or 0.5 kb of the MMP20 promoter. An examination of protein stability showed that the half-life of wild type DLX3 protein was less than 12 h whilst that of both deletion mutants was longer than 24 h. Endogenous Dlx3 was also found to be continuously expressed during ameloblast differentiation. Since inactivating mutations in the gene encoding MMP20 are associated with amelogenesis imperfecta, the inability of 4bp-del or 2bp-del DLX3 to induce MMP20 expression suggests a possible involvement of such mutations in the enamel phenotype associated with TDO syndrome or ADHHAI.