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AMELOGENESIS IMPERFECTA

Clinical Report

ANAR PATEL* , A.R. CHAUDHARY** , BHAVIN DUDHIA*** , NARESH SONI**** , ABHISHEK BAROT*****

ABSTRACT

Amelogenesis Imperfecta (AI) is a diverse collection of inherited diseases that exhibit quantitative or qualitative tooth enamel defects in the absence of systemic manifestations. The AI trait can be transmitted by either autosomal dominant, autosomal recessive or X-linked modes of inheritance. Mutations in the amelogenin, enamelin, and kallikrein-4 genes have been demonstrated to result in different types of AI and a number of other genes critical to enamel formation have also been identified and proposed as candidates for AI. Variants of AI generally are classified as hypoplastic, hypocalcified, or hypomaturation types based on the primary enamel defect and teeth affected may be discoloured, sensitive or prone to disintegration.This defect is entirely ectodermal, since mesodermal components of the teeth are normal. It is necessary to diagnose the case and provide durable functional and esthetic management of these patients, as the unaesthetic appearance has a definite negative psychological impact.This article presents a case report of 26 years female patient with Amelogenesis imperfecta. Key words: Amelogenesis Imperfecta, Enamel, Genetic

INTRODUCTION & REVIEW

Amelogenesis imperfecta (AI) encompasses a heterogeneous group of developmental disorders that demonstrates alterations in the enamel. It is characterized by clinical and genetic heterogeneity in the absence of systemic abnormalities or diseases.1 - 4 AI is also known by varied names such as hereditary enamel dysplasia, hereditary brown enamel, and hereditary brown opalescent teeth. 1, 5 Amelogenesis Imperfecta (AI) encompasses a complicated group of conditions that demonstrate developmental alterations in the structure of the 1, 5 - 7 enamel in the absence of a systemic disorder. The prevalence of this condition has been expected to range from 1 in 718 to 1 in 14,000, depending upon the population studied. 1, 4 - 6, 8 - 11 Hypoplastic AI represents 60 ­ 73% of all cases, hypomaturation AI represents 20 ­ 40%, and hypocalcification AI represents 7%. 1, 5, 11 No racial predilections of the AI 8 have been reported. Both primary and permanent 2, 5, 6, 8, 12, 13 dentitions are usually affected.

AI is caused by mutations in genes that control amelogenesis and follows inheritance patterns of autosomal-dominant, autosomal recessive or X3 - 5, 8, 12, 14 linked modes of transmission. There are also patients for whom a family history cannot be identified but where a mutation is present. 2, 5, 6, 8, 12, 13 The inheritance pattern of X-linked disorders dictates that male to male transmission cannot occur. Conversely, all female offsprings of the affected male must be affected. Affected females have a 50% of passing on the trait to the offspring of 1, 9 either sex. Mutations in the amelogenin gene (AMELX) cause X-linked amelogenesis imperfecta, while mutations in the enamelin gene (ENAM) cause autosomal-inherited forms of amelogenesis imperfecta. Recent reports involve kallikrein-4 (KLK4), MMP-20 and DLX3 genes in 1 - 3, 9, 13, 14 the etiologies of some cases. Witkop and Sauk listed the varieties of AI, divided according to whether the abnormality lay in a reduced amount of enamel (hypoplasia), deficient

*Sr. Lecturer (Oral Medicine & Radiology Department ) **Professor & Head (Oral Medicine & Radiology Department ) ***Reader (Oral Medicine & Radiology Department ) ****Post-graduate Student (part II) (Oral Medicine & Radiology Department ) *****Post-graduate Student (part I) (Oral Medicine & Radiology Department ) AHMEDABAD DENTAL COLLEGE & HOSPITAL, BHADAJ-RANCHHODPURA ROAD, TA:- KALOL DIST:-GANDHINAGAR.

ADDRESS FOR AUTHOR CORROSPONDENCE : DR. Anar Patel, PHONE:- 97273 95438 The Journal of Ahmedabad Dental College and Hospital; 2(1), March 2011 - August 2011 39

ANAR PATEL et. al. : Amelogenesis Imperfecta

calcification (hypocalcification), or imperfect maturation of the enamel (hypomaturation), and 1, 5, 6, 11, 13, 14, also recognized the combine defects

Table 1 : Classification of Almelogenesis Imperfecta (Witkop and Sauk)

Type I hypoplastic IA Hypoplastic, pitted autosomal dominant IB Hypoplastic, local autosomal dominant IC Hypoplastic, local autosomal recessive ID Hypoplastic, smooth autosomal dominant IE Hypoplastic, smooth X-linked dominant IF Hypoplastic, rough autosomal dominant IG Enamel agenesis, autosomal recessive Type II hypomaturation IIA Hypomaturation, pigmented autosomal recessive IIB Hypomaturation IIC Snow-capped teeth, X-linked IID Autosomal dominant? Type III hypocalcification IIIA Autosomal dominant IIIB Autosomal recessive Type IV hypomaturation hypoplastic with taurodontism IVA Hypomaturation hypoplastic with taurodontism, autosomal dominant IVB Hypoplastic hypomaturation with taurodontism, autosomal dominant Clinically, AI appears as an alteration of enamel formation resulting in hypoplasia, 5, 14 hypocalcification, and hypomaturation. Enamel hypoplasia results in a decreased quantitative enamel formation. The enamel in hypocalcification appears normal but poorly mineralized while hypomaturation results in an abnormal mineralization in the final stages of tooth formation. The most common form, the hypoplastic type, is 5, 10 deficient in normal enamel. The crowns of the teeth appear blanched, snow-capped, yellow-

brown, pitted or grooved. Radiographic examination usually show a full complement of teeth, but the crowns of the teeth either have very thin enamel or lack enamel completely.5, 7, 14 Other dental features associated with AI include quantitative and qualitative enamel deficiency, pulpal calcifications, taurodontism and root malformations, impaction of permanent teeth, progressive root and crown resorption, congenitally missing teeth and anterior and posterior open bite occlusion.3, 16 Diagnosis involves exclusion of extrinsic environmental or other factors, establishment of a likely inheritance pattern, recognition of phenotype and correlation with the dates of tooth formation to exclude a chronological developmental 1, 3, 4 disturbance. Also dental radiography in form of OPG & full mouth intraoral radiographs plays a vital role in diagnosing the difference in density of enamel in AI patients and normal patients along with dentin thickness, pulp canal and root length.3 Treatment planning for patients with amelogenesis imperfecta is related to many factors: the age and socioeconomic status of the patient, the type and severity of the disorder, and the intraoral situation. An interdisciplinary approach is necessary to evaluate, diagnose and resolve esthetic problems using a combination of prosthodontic, orthodontic 6, 12 and restorative treatment. This paper describes various dental manifestations, the functional and esthetic rehabilitation of AI patient. It also emphasizes on the fact that radiology plays a vital role in diagnosing such conditions.

5, 7, 8, 14

CASE REPORT

A 26 year old female patient reported to the department of Oral medicine and radiology, Ahmedabad Dental College & Hospital with a chief complain of discoloured teeth since childhood and associated complain of difficulty in chewing hard food.

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ANAR PATEL et. al. : Amelogenesis Imperfecta

She had not sought any treatment previously, since the condition was not resulting in any other systemic manifestations. Since she had inherited the condition from her mother, she accepted it as part of her appearance. But now because of psychological impact of her appearance and difficulty in chewing hard food, she came to our dental OPD for treatment. Patient resided in a nonfluoridated area since her birth. Her natal, postnatal and medical histories were not significant. Her mother & maternal aunt also suffered from the same condition. The pedigree chart could be constructed as in.

Fig.-2: Intraoral photograph showing generalized brownish stains, hypoplastic enamel with severe pitting and anterior open bite

Fig.-1: Pedigree chart of the Case

Past dental history revealed that her deciduous teeth were also similarly discoloured. No history of any eruption disturbances or previous extraction. From a functional point of view, she had been avoiding hard food substances; at the same time, remaining caries free, except for root canal treatment in 15, 16, 46 & 47. The patient's hair, skin and nails were normal. Mandible was markedly prognathic. On intraoral examination, it was found that she had a normal complement of teeth except that 12 & 22 were missing (13 was also missing clinically but retained root piece of 13 was confirmed radiographically). The thickness of enamel was reduced on all teeth and was completely chipped off from some teeth exposing the dentin. The surfaces of the teeth were rough. The teeth, in general, exhibited orange brown discoloration, with diffuse pitting present on all surfaces of the teeth. She had high arched U-shaped palate, anterior open bite with Class III malocclusion. Periodontal condition was sound with satisfactory oral hygiene.

Fig.-3: Intraoral photograph showing high arched U-shaped palate with rough malformed enamel and temporary restoration in 25, 26

The diagnostic cast of patient were made which showed rough surface and malformed shape of all teeth.

Fig.-4: Photograph of diagnostic casts showing rough surface and altered shape of all teeth

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The Journal of Ahmedabad Dental College and Hospital; 2(1), March 2011 - August 2011

ANAR PATEL et. al. : Amelogenesis Imperfecta

Radiographic investigations included an Orthopantomogram (OPG) and full mouth intraoral periapical (IOPA) radiographs. OPG showed missing 12 and 22. Crowns of all teeth showed reduced enamel thickness with normal dentin. Root morphology of all teeth was completely normal.

pedigree chart, clinical and radiographic features. Esthetics and functional limitations were the reason that brought patient for treatment. The treatment proposed for her included oral prophylaxis, surgical removal of root piece of 13, restoration of malformed teeth, crown placement following root canal treatment, esthetic rehabilitation with fixed full cast crown of porcelain fused to metal. Along with that, oral hygiene instructions were given to the patient. Regular brushing of the teeth using the modified Bass technique was taught to the patient to be practiced twice a day using a soft toothbrush and fluoridated toothpaste followed by rinsing with 2% w/v of Chlorhexidine gluconate for 15 days.

Fig.-5: Photograph of OPG showing reduced thickness of enamel on all teeth, missing 12 & 22, root canal treated 15, 16, 46, and 47 with prognathic mandible.

DISCUSSION

Amelogenesis imperfecta is a developmental, often inherited disorder, affecting dental enamel. It usually occurs in the absence of systemic features 1, 5 and comprises of diverse phenotypic entities. Compared with Dentinogenesis imperfecta the patient does not usually complaint of sensitivity 4 since the dentin is intact. This is in accordance with our case where patient was asymptomatic except for unpleasant appearance and functional difficulty. The predominant clinical manifestations of affected individuals are enamel hypoplasia (enamel is seemingly correctly mineralized, but thin), hypomineralization (subdivided into hypomaturation and hypocalcification), or a combined phenotype, which is seen in most cases. The trait of AI can be transmitted by an autosomaldominant, autosomal-recessive, or X-linked mode of inheritance.1 - 3, 5, 9 - 12 Clinical presentation of the AI varies according to its type. In the hypomaturation type, the affected teeth exhibit mottled, opaque white-brown yellow discoloured enamel, which is softer than normal. In radiographs, the thickness of enamel is normal, but the density is the same as that of the dentin. The hypocalcified type shows pigmented, softened, and easily detachable enamel. Radiographically,

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Examination of the IOPA radiographs revealed a normal pulp chamber and root canal spaces with no signs of obliteration, missing 12 & 22 with retained root piece of 13. The enamel was almost half its usual thickness, but was more radiodense than the dentin.

Fig.-6: Photograph of IOPA of upper anterior region showing 11, 14, 21& 23 with thin enamel & normal dentin, pulp canal and root length and retained root piece of 13

A provisional diagnosis of hypomature AI was proposed along with a differential diagnosis of environmental enamel hypoplasia, Dentinogenesis imperfecta and dentin dysplasia. The diagnosis of hypomature, pigmented, autosomal recessive type of amelogenesis imperfecta with partial anodontia was confirmed on the basis of typical family history,

The Journal of Ahmedabad Dental College and Hospital; 2(1), March 2011 - August 2011

ANAR PATEL et. al. : Amelogenesis Imperfecta

enamel thickness is normal, but its density is even less than that of the dentin. In hypoplastic type, the enamel is well-mineralized but its amount is reduced. Radiographs exhibit a thin peripheral outline of radiodense enamel, and low or absent 6, 9 cusps. Clinical and radiographic appearance of the teeth of our case was harmonious with rough pattern hypomature type of AI. Clinically, skeletal anterior open bite is seen in approximately 50% of patients with AI of either Xlinked or autosomal inheritance type. 3, 4, 6 This is in accordance with present case. Non enamel dental anomalies like taurodontism, elongation of pulp chamber due to apical displacement of root furcation and pulp calcifications occur with increased frequency in these patients.3, 6 Along with this, congenitally missing teeth (partial anodontia), high arched palate is also seen, 3, 16 which was present in the our case. Diagnosis is based on the family history, pedigree plotting, meticulous clinical and radiological 3, 4 observation. Pedigree chart was constructed for present case which showed a vertical as well as horizontal distribution of the AI. Patient's mother and her maternal aunt were affected by similar condition. But her brother and her father's family side was not affected. This indicated autosomal recessive type of amelogenesis imperfecta. Dental radiographs of AI teeth provide important information to the clinician with respect to the degree of enamel mineralization to design an appropriate treatment plan. Evaluation of enamel density changes in AI teeth are generally made by

contrasting the enamel with the dentin; enamel that has a radiopacity similar to or less than that of dentin 3 is considered mineral deficient. In present case also enamel density was comparable to dentin. Amelogenesis imperfecta presents with problems of socialization, function and discomfort which may be managed by early vigorous intervention, both preventively and restoratively. In adult, the permanent dentition may be protected by use of full cast crowns on posterior teeth and veneers on anterior teeth.3, 8, 16 Root canal treatment and esthetic crown replacement for decayed teeth should be done to achieve the Jackson's triad of esthetic harmony, structural balance and functional efficiency. A multidisciplinary approach consisting of an orthodontist, prosthodontist and endodontist should be planned.1, 3, 7 In our case also similar approach was considered mainly concentrating on esthetics and functional durability.

CONCLUSION

Amelogenesis imperfecta is a heterogeneous developmental disorder presents with severe dental anomalies. The dentist has to diagnose the condition as early as possible to balance the decision for early intervention and long-term survival of the restorations. Dental practitioners should also consider the social implications for these patients and intervene to relieve their suffering. Thus, this article is an attempt to improve the clinician's knowledge about the clinical & radiographic diagnosis as well as intervention required for such a condition.

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REFERENCES

1. Mayur Chaudhary, Shweta Dixit, Asha Singh, Sanket Kunte. Amelogenesis Imperfecta : Report of a case and review of literature. JOMFP 2009;13(2):70 - 77. 2. Maria Cristina Leme Godoy dos SANTOS, Sergio Roberto Peres Line. The genetics of amelogenesis imperfecta. A review of the literature. J Appl Oral Sci 2005;13(3):212-7. 3. Sujatha S. Reddy, Aarthi Nisha V, Harish BN. Hypoplastic amelogenesis imperfecta with multiple impacted teeth - report of two cases. J Clin Exp Dent 2010;2(4):207-11. 4. Titus Peter, Smily Titus, George Francis. Full mouth rehabilitation of a case with amelogenesis imperfecta. Streamdent 2010;1(3):250-2. 5. Narendranath Reddy. Y, Siva Prasad Reddy. E. Amelogenesis Imperfecta : A case report. Annals and essences of dentistry 2010;2(1):1921. 6. Emin Murat CANGER, Peruze CELENK, Murat YENISEY, Selcen Zeynep ODYAKMAZ. Amelogenesis Imperfecta, Hypoplastic Type associated with some dental abnormalities : A Case Report. Braz Dent J 2010;21(2):170-174. 7. Neville BW, Damm DD, Allen CM, Bouquot JE. Chaptr 2: Abnormalities of teeth. In: Oral and Maxillofacial Pathology. 2nd ed. Pub: Saunders: an imprint of Elsevier; 2005. P. 89. 8. Edward Huen-Tai Ho. Amelogenesis imperfecta - a case report. Hong Kong Dental Journal 2006;3(2): 123-7. 9. Ellen Rose Bundzman, Adriana Modesto. Hypomaturation Amelogenesis Imperfecta : Account of a family with an X-linked inheritance pattern. Braz Dent J 1999;10(2):111-6. 10. W. Kim Seow. Clinical diagnosis and management strategies of amelogenesis variants. Pediatric Dentistry 1993;15(6): 384-93. 11. Rajendran R. Chptr: 1. Developmental disturbances of oral and paraoral structures. In: Rajendran R, Sivapathasundharam B, editors. Shafer's Textbook of Oral Pathology. 6th ed. Pub: Elsevier; 2009. p. 48. 12. Ranganath V., Ashish S. Nichani, Soumya V. Amelogenesis imperfecta : A challenge to restoring esthetics and function. Journal of Indian Society of Periodontology 2010;14(3):195-7. 13. Hiroshi Sekiguchi, Harunobu Tanakamaru, Kiyoshi Minaguchi, Yukio Machida & Masashi Yakushiji. A case of amelogenesis imperfecta of deciduous and all permanent teeth. Bull. Tokyo dent. Coll. 2001;42(1):45-50. 14. Peter JM Crawford, Michael Aldred, Agnes Bloch-Zupan. Amelogenesis Imperfecta. Orphanet Journal of rare diseases 2007;17(2):1-11. 15. Ahmet Keles, Binnur Pamukcu, Ferah Isik, Deniz Gemalmaz, M Zeki Guzel. Improving quality of life with a team approach - A case report. Int J Adult Orthod Orthognath Surg 2001;16(4):293-9. 16. Kagan Gokce, Ceyhun Canpolat, Emre Ozel. Restoring function and esthetics in a patient with amelogenesis imperfecta : A case report. The Journal of Contemporary Dental Practice 2007;8(4):1-6.

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