Alteración del gen AMELX en amelogénesis imperfecta. Una breve revisión / Alteration of the AMELX gene in amelogenesis imperfecta. A brief review

Resumen La amelogénesis imperfecta es un grupo de trastornos de desarrollo del esmalte dental asociados principalmente con mutaciones en el gen AMELX. Clínicamente presenta diferentes fenotipos que afectan la estructura y función del esmalte, tanto de la dentición primaria como secundaria. El objetivo de este estudio fue realizar una revisión bibliográfica de las funciones y mutaciones de AMELX relacionadas con amelogénesis imperfecta. Se llevó a cabo una revisión bibliográfica en dos bases de datos: PubMed y Web of Science, usando las palabras clave “AMELX”, “amelogenina”, “amelogénesis imperfecta” y “mutación de AMELX”. Fueron revisados 40 artículos y se encontró que AMELX es el gen predominante en el desarrollo del esmalte dental y de la amelogénesis imperfecta, alterando la estructura de la amelogenina. En los últimos años se han descrito las características en el proceso de amelogénesis imperfecta con diferentes fenotipos de esmalte hipoplásico o hipomineralizado y se han reportado diferentes mutaciones, con lo que se ha determinado la secuenciación del gen y las posiciones de las mutaciones.

Abstract Amelogenesis imperfecta is a group of developmental disorders of the dental enamel that is mainly associated with mutations in the AMELX gene. Clinically, it presents different phenotypes that affect the structure and function of dental enamel both in primary and secondary dentition. The purpose of this study was to conduct a literature review on the AMELX functions and mutations that are related to amelogenesis imperfecta. A literature search was carried out in two databases: PubMed and Web of Science, using the keywords “AMELX”, “amelogenin”, “amelogenesis imperfecta” and “AMELX mutation”. Forty articles were reviewed, with AMELX being found to be the predominant gene in the development of dental enamel and amelogenesis imperfecta by altering the structure of amelogenin. In the past few years, the characteristics of the amelogenesis imperfecta process have been described with different phenotypes of hypoplastic or hypo-mineralized enamel, and different mutations have been reported, by means of which the gene sequencing and the position of mutations have been determined.

Diversity of clinical, radiographic and genealogical findings in 41 families with amelogenesis imperfecta

Abstract Amelogenesis imperfecta (AI) is a group of enamel development disorders that alter the structure and chemical composition of the tissue. There is great variability in the clinical presentation; according to Witkop, AI can be categorized into 14 subtypes, which makes its diagnosis extremely complex. Objective: This study aimed to describe and determine the frequency of clinical and radiographic features and inheritance patterns found in 41 Chilean families diagnosed with diverse types of AI. Material and Methods: We analyzed the clinical records, photographs, pedigrees and radiographs of 121 individuals recruited between 2003 and 2016. All of the information was included in a database that was analyzed using the application Stata 14. Results: The 72 affected individuals had average age of 16 years, and no sex association with the presence of AI was found. The most frequent clinical subtypes were as follows: 43% hypomature, 25% hypoplastic, 21% hypomature/hypoplastic, 7% hypocalcified and 4% hypocalcified/hypoplastic. The number of severely affected teeth was 22, which occurred in the patients with hypocalcified and hypocalcified/hypoplasic AI who presented the highest number of damaged teeth. Caries and periodontal disease were found in 47 and 32% of the patients, respectively. Malocclusions were observed in 43% of the individuals with AI, with open bite being the most frequent. Radiographically, the thickness of the enamel decreased in 51% of the patients, and 80% showed decreased radiopacity of the enamel compared to that of dentin. Autosomal dominant inheritance pattern was found in 37% of the families with hypoplastic AI, and autosomal recessive pattern was present in 56% of the other clinical subtypes, but more frequently in those affected with hypomature and hypocalcified AI. Conclusion: Of the five clinical subtypes, autosomal recessive hypomature, autosomal dominant hypoplastic and autosomal recessive hypomature/hypoplastic AI were the most prevalent subtypes in this group.

Amelogenesis Imperfecta, hypoplastic type associated with some dental abnormalities: a case report

Amelogenesis imperfecta (AI) is a hereditary disorder expressing a group of conditions that cause developmental alterations in the structure of enamel. AI is a serious problem that reduces oral health-related quality of life and causes some physiological problems. The treatment of patients with AI may upgrade the quality of life and reinforce their self-esteem. Among the treatment options for AI, full-mouth metal reinforced porcelain restoration constitutes an important alternative because of its properties. This paper presents a case of AI of the hypoplastic rough type associated with a group of dental anomalies, and describes the prosthetic management of the patient. A 26-year-old female patient presented with a chief complaint of discolored teeth. Clinical and radiographic examination of the patient confirmed the diagnosis of rough pattern hypoplastic AI. The patient was treated with full-mouth metal reinforced porcelain fixed bridge. The adaptation of the temporomandibular joints and masticatory muscles was carefully observed periodically during 4 months and, after this period, the patient tolerated well her new vertical dimension. The patient received instructions on cleansing of the subpontic and interproximal areas. Follow-up visits were scheduled at 3 months and then at 6 months. No esthetic or functional problems were seen after the follow up period.

Amelogenesis imperfecta (AI) é uma desordem hereditária que expressa um grupo de condições que causam alterações de desenvolvimento na estrutura do esmalte. A AI é um problema grave que compromete a qualidade de vida relacionada à saúde bucal e causa alguns problemas psicológicos. O tratamento de pacientes com AI pode melhorar sua qualidade de vida e reforçar sua auto-estima. Dentre as opções de tratamento para AI, a restauração de toda a boca com porcelana reforçada com metal representa uma alternativa importante devido a suas propriedades. Este artigo apresenta um caso de AI do tipo hipoplásica rugosa associada a um grupo de anomalias dentais, e descreve o tratamento protético da paciente. Uma paciente de 26 anos apresentou-se com queixa principal de dentes manchados. O exame clínico e radiográfico da paciente confirmou o diagnóstico de AI hipoplásica rugosa. A paciente foi tratada com a construção de próteses fixas de porcelana reforçada com metal em toda a boca. A adaptação das articulações temporomandibulares e dos músculos mastigatórios foi cuidadosamente observada periodicamente durante 4 meses e, após este período, a paciente mostrou tolerar bem sua nova dimensão vertical. A paciente recebeu instruções sobre limpeza das áreas sob o pôntico e áreas interproximais. As visitas de acompanhamento foram agendadas a cada 3 meses e subseqüentemente a cada 6 meses. Não foram observados problemas estéticos ou funcionais após o período de acompanhamento.

Tecnología en el diagnóstico de caries / Technology in caries diagnosis

Desde el inicio de nuestra profesión, los dentistas hemos buscado el método ideal para el diagnóstico correcto de caries, sobre todo en caries incipientes. Esto nos lleva a ®esperar y observar, o perforar y tratar¼. Muchos estudios han demostrado fallas en el diagnóstico y variaciones en la interpretación de resultados al examinar clínicamente con el explorador. Radiográficamente, tenemos también un alto porcentaje de diagnóstico incorrecto, siendo su mejor aplicación en caries proximales. Existen otros métodos en la actualidad que nos ayudarían a llegar a un diagnóstico más cercano a la realidad, utilizando métodos, ya sea con rayo láser como el Diagnodent o aun mejor con un sistema de transluminación y captura de imágenes en la computadora.

Since the early days, we as dentist have been trying to make a proper diagnosis for our patients, specially in terms of decay. We are not certain on «wait and see. Or perforate and treat¼. Recent studies have shown in the literature incorrect diagnosis and variations on the interpretation of the clinical findings, specially when the explorer is the instrument to use. Radiographically, there is a high percentage of failure, unless bitewings, which have a better visualization of it. Still one of the best methods to find proximal decay. Nowadays we have improved technics and equipment that can help us reach our goal, like caries detection dye, laser diagnostic tool like the Diagnodent, and even better, an instrument that help us to see in the computer with transillumination and capture the image in a computer data base.

Amelogênese imperfeita: uma abordagem clínica, genética e histológica / Amelogenesis imperfecta: histological, genetical and clinical approach

A amelogênese imperfeita é caracterizada por defeitos estruturais do esmalte, os quais podem acometer severamente a estrutura dentária. Saber diagnosticar e classificar corretamente esta anomalia é muito importante para a realização de um tratamento adequado ao paciente. Este trabalho visa descrever, a partir de uma revisão da literatura, as características clínicas, histológicas e genéticas relacionadas com a amelogênese imperfeita, além de apresentar o relato de um caso clínico de uma paciente com a anomalia em ambas as dentições. Neste trabalho, são descritos os aspectos clínicos e radiográficos, a análise genética por meio do heredograma da família e a análise ao microscópio eletrônico de varredura do esmalte dos dentes decíduos comprometidos

Amelogenésis imperfecta, tipo hipoplásica: informe de una familia / Imperfect amelogenesis, hypoplastic type: family report

Se presenta una familia, en la cual algunos de sus miembros son afectados por amelogenésis imperfecta. Se efectúa un estudio clínico y anátomo-patológico con microscopio electrónico de barrido de uno de sus integrantes. La AI es una enfermedad que afecta tanto la formación como la maduración normal del esmalte cuyo origen es hereditario