Restorative Dentistry

Amelogenesis imperfecta: The multidisciplinary approach.A case report

Suna Toksavul, DDS. PhDVMübin Ulusoy. DDS, PhD^/MuraíTijrkün, DDS,ÖviJl Kümbüloglu, DDS, PhD"

Ameiogenesis impertecta is a hereditary devsiopmentai disorder of the dentai enamei, in both primary andpermanent dentition. The main ciinicai characteristics are extensive ioss of tooth tissue, poor esthetics,and tooth sensitivity. Transmission ol the gene takes place by either aulosomai, dominant X-iinked, or re-cessive modes. This ciinicai report describes a treatment sequence based on a muitidisciplinary approach.A 21-year-oid giri with hypopiastic ameioggnesis imperfecta was referred to the Ege University Schooi ofDentistry oiinic. She was concerned about the poor appearance and sensitivity of her teeth. The patientpresented with an anterior open bite, aithough orthodontic treatment had been compieted previousiy.Periodontai gingiveetomy of her posterior teeth foiiowed by endodontic treatment where indicated was pro-posed. The prosthodontie treatment consisted ol metai ceramic Iixed partiai dentures ol precious aiioy. Atthe end of treatment, tunction and esthetics were improved to a ievei acceptabie to both ihe patient andthe dentai team. (Quintessence ¡nt 2004;35:11-14)

Key words: amelogenesis imperiecta, muitidiscipiinary approach, open bite, orai rehabiiitation

Amelogenesis imperfecta is a hereditary develop-mental disorder of the dental enamel, in hoth the

primary and permanent dentitions.^ Amelogenesis im-perfecta was first described in 1890, but not until 1938did Finn^ classify it as a separate entity from dentino-genesis imperfecta. Its occurrence varies between 1 in14,000 and 1 in 4,000, depending on the diagnosticcriteria used and the population group studied.'

Amelogenesis imperfecta's inheritence is mainly au-tosomal domitiant, but autosomal recessive or X-linked inheritance also can occur. Wide variation oc-ctiis in phenotype because of variahle gene expressionor different gene defects.''

The main clinical problems of amelogenesis imper-fecta are extensive loss of tooth tissue, poor esthetics,and tooth sensitivity.^ Pulp and dentin are usually nor-

'Professor, Department of Prosthodonties, Ege University School ofDentistry, Izmir, Turkey.

^Associate Professor, Department of Prosthodcntics, Ege University Schooi

of Dentistry, izmir, Turkey.

^Associate Professor, Departmenl of Endodonfics, Ege Universify Scliool of

Denfistry, Izmir, Turkey

'Research Assisfant, Deparfment of Prosfhodontics, Ege university Schoolof Dentistry, izmir, Turkey

Reprint requests: Proi Dr Sura Taksavui, Department ol Prosthodohtics,Ege University Schooi of Dentistry, Bornova Izmir, Turkiye, 351CC. E-maii:sunatoksavu l e yahoo.com

mal, and the teeth are usually caries resistant.Amelogenesis imperfecta has been associated with in-clusions and abnormalities in dental eruption, congen-itally missing teeth, anterior open bite, pulpal calcifi-cations, root and crown résorption, hypercementosis,root malformations, and taurodontism.^

Classification of the disorder is complex but can besimplified into three groups based upon the predomi-nant clinical and radiographie appearance of tbeenamel defect and on the mode of trait inheritance.Different groups give rise to a wide variation in clini-cal presentation, ranging from discoloration to softand/or deficient enamel.

1. The hypopiastic type results from errors affectingthe dental tissue protein matrix, which is botb defi-cient in amount and irregular in deposition.Calcification is normal, but there are areas wherethe thickness of the enamel is reduced.

2. In the hypocalcified type, the enamel is fully formedon a normal matrix but is not fully calcified.

3. The enamel of the hypomature type is of normalthickness hut has a mottled appearance and isslightly softer than normal enamel.̂

This case report outlines the management of a pa-tient with amelogenesis imperfecta and illustrates the

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Fig 1 Views of a patient diagnosed withamelogenesis imperfecta at initial presen-tation: (ieft) mouth open: (right) teeth in oc-clusion.

Fig 2a (ieft) f^andibular right secondmolar before penadontal treatment.

Fig 2b (right) Mandibular iight secondmolar following periodontai treatment.

desired inter-relationship between periodontics, en-dodontics, and prosthodontics.

CASE REPORT

A 21-year-old woman suffering from a poor self-image, was referred to the Department of Prosfho-dontics at the School of Dentistry, Ege Universify,Her major complaints were the poor appearance ofher teeth and the inability to chew properly. Shestated that she had received orthodontic treatment inthe past but was not satisfied with the outcome. Hermedical history was uneventiiil. The patient reportedthat no other family member other than herself hadthe same dental problems.

Maxillary left and right canines (teeth 23[U] and13[e], respectively), first premolars (teeth 24[12] and14[5], respectively), and second molars (teeth 27[15]and 17[2], respectively) and the mandibular left firstpremolar (toofh 34[21]) were noted as missing in clin-ical examinafion, Radiographic examination revealedthat missing feeth were impacted, so treatment wasinitiated with the extraction of impacted teeth.

Clinical and radiographie examinations revealedthat only left and right central (teeth 21[9] and 11[8],respectively) and lateral (22[10] and 12[7], respec-tively) incisors, second premolars (teeth 25[13] and15[4], respectively), and first molars (teeth 26[14] and16[3], respectively) were present in the maxillary arch,whereas all mandibular teeth were present except forthe left first premolar and third molars. The patientpresented with the hypoplastic type of amelogenesisimperfecta (Fig 1).

The patient's oral hygiene was poor and a generalizedgingivitis with hyperpiasia was noted. The mandibularright first premolar and first molar were almost com-pletely covered with gingival tissue overgrowth (Fig 2).

The mandibular right second molar did not respondto thermal and electrical pulp testing and was sensitiveto percussion, whereas all other teeth responded toboth pulp testings.

Prior to treatment, diagnostic casts were obtained,Tbe clinical crowns of mandibular right posteriorteeth were considered inadequate for prostheticrestoration. Therefore, coronal lengthening techniqueswere considered to improve the height of the clinicalcrowns, Gingivectomy and gingivoplasty were appliedto botb jaws, particularly the mandibular posteriorteeth having inadequate clinical crown lengths. Ahealing period of 4 weeks was allowed for the soft tis-sues to mature adequately and to allow for an optimalesthetic result. After periodontal surgery, root treat-ment of the mandibular right second molar was car-ried out. Before coronal buildup of the first moiar witha glass-ionomer cement (Ketac-Silver, ESPE), a suit-ably sized wrought metal para-post (Whaledent) wasinstalled into the distal root canal. Coronal restorationof the second molar was performed using a com-pomer. Although surgical crown lengthening had beenmade, length of the clinical crown of the mandibularright first premolar was still inadequate for prostheticrestoration. Therefore, its crown length was increasedwith pin-retained compomer restoration.

Following periodontal surgery and endodontictreatment, tooth preparations were completed forporcelain-fused-to-metal fixed partial dentures (FPDs)and crowns.

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Fig 3a (left¡ Prepared maxiilary teeth.

Fig 3b (rigtit) Prepared mandibuiar leeth.

Fig 4 (left) Poiyvinyl siioxane impression.

Fig 5 (right) Metal occiusai surfaces mtiie maxiiiary cast model.

Fig 6 (ieft) View of compieted maxiiiaryrestorations.

Fig 7 (right) Frontai view after prosthetictreatment.

Fig Sa Corrpieted mandibular restorationsexcept right second molar in the cast mode i

Fig 8b View ot oompieted mandibuiarrestorations except right second moiar

Fig 8c Compieted mandibuiar right sec-ond moiar.

The teeth were reduced to allow for 1.5 mm ofrestorative material on the occusal and incisai sur-faces. The margins were prepared with a knife-edgedfinish line for all the teeth (Hg 3).

Impressions were taken with a polyvinyl siloxane-based impression material (Fig 4)- A precious metalalloy (DegudentG, Degussa) was used for alt of theFPDs and crowns. Porcelain-fused-to-metal FPDswere applied on hoth sides of the maxillary arch be-tween the lateral incisors and second premolars andbetween the left canine and second premolar teeth onthe mandibular arch. Due to inadequate occlusal verti-cal dimension, second premolars and first molars on

both sides oí the maxillary arch were fabricated withmetal occiusal surfaces (Fig 5).

Following normal prosthetic sequence, marginal fit-ting, esthetic appearance, and occiusal fit were estab-hshed. The restorations were cemented with a polycar-boxylate cement (Poly-F, Dentsply) (Figs 6 to 8),

DISCUSSION

The restoration of esthetics and function in patientswith amelogenesis imperfecta may be achieved witha dedicated team approach. In this case, meticulous

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Fig 9 Reduced open bile. Fig 10 One year later. Fig 11 Two years laler.

attention to detail, from diagnosis to postdeliverymotiitoring, allowed a controlled and logical treatmentsequence.^

There are many manifestations of enamel hypopia-sia, and there is no standard formula for successfultreatment. The esthetic treatment of enamel hypopia-sia is limited to the removal of surface stains, elimina-tion of the defective tooth tissue, and masking of thedefects. Attempts should be made to achieve treatmentobjectives while keeping the loss of tooth substance toa minimum.'

There are many reports*'̂ in orthodontic literatureon the association between amelogenesis imperfectaand open bite, with occurrences ranging from 24% to60%. Witkop and Sauk'" regarded the open bite to bea result of defects in tbe eruption meebanism sec-ondary to alterations in tbe organic matrix of tbeenamel. Thus, the bypersensitivity to heat and coldwould be compensated by a lingual interposition tomecbanicaliy prevent tbe alveolar growtb. Rowley etal* eoneluded tbat the association was due less to localfactors and more to a genetic abnormality of craniofa-cial development, which would include skeletal openbite features. In tbe current case, tbe open bite was re-duced to a level aceeptahie to the patient (Fig 9).

Many different materials and methods currentlyavailable bave made it both exciting and confusing fordental practitioners. It sbould be pointed out tbattbere are limitations and that their apphcations arenot universal." It bas heen noted in reports '̂"" tbat ad-hesive teebniques, overdentures, porcelain-fused-to-metal crowns and FPDs, full porcelain crowns andinlay/onlay restorations are used for the prosthodontictreatment. In the present case, a precious metal alloywas utilized in tbe restorative procedure. Tberefore,both tbe marginal fit and tbe eolor stability of tberestorations were satisfactory.

At tbe follow-up sessions, tbe patient reported greatsatisfaction witb tbe outcome, and her family de-

scribed ber as being more extroverted. Tbis case illus-trates tbat interdisciplinary approacbes are required totaiie into account all factors involved in order toachieve a satisfactory resolution (Figs 10 and 11).

REFERENCES

1. Coley-Smith AC, Brown CJ. Case report: Radical manage-ment oí an adolescent with amelogenesis imperfecta. DentUpdate 1996;23:434-435

2. Finn SB. Heredity opaleseent dentition. 1. An analysis of theliterature on hereditary anomalies of tooth color. J Am DentAssoc 1938;24;1240-1249.

3. Greenfield R, tacono V, Zove S, Baer P. Feriodonlal andprosthodontic treatment of amelogenesis imperfecta: A clin-ieal report. J Prosthet Dent 1992 ;68:572-574.

4. Hall RK, Phakey P, Palamara J, McCredie DA, Amelo-genesis imperfecta and nephrocalcinosis syndrome. Casestudies of clinical features and ultrastrueture of toothenamel in two siblings. Oral Surg Oral Med Oral PatholOral Radiol Endod 1995;79:583-592,

5. Encinas RP, Garcia-Espona I, de Móndelo JMNR. Amelo-genesis imperfecta; Diagnosis and resolution of a case withhypopiasia and hypo calcification of enamel, dental agenesisand skeletal open bite. Quintessence Int 2001;32:183-189.

6. Williams WP, Becker LH. Amelogenesis imperfecta;Functional and esthetie restoration of a severely compro-mised dentition. Quintessence Int 2000;31:397-403.

7. Li RWK. Adhesive solutions: Report of a case using multi-ple adhesive techniques in the management of enamel hy-popiasia. Dent Update 1999;26;277-287.

8. Baekman B, Holm AK. Amelogenesis imperfecta: Preva-lence and incidence in a northern Swedish eountry.Community Dent Oral Epidemiol 1986;14:43-47

9. Rowley R, Hill FJ, Winter GB, An investigation of the asso-ciation hetween anterior open-bite and amelogenesis imper-fecta. Am J Orthod 1982 ;81:229-235,

10, Witkop CI, Sauk JJ, Heritable defects of enamel. In; StewartRE, Prescott GH (eds). Oral Faeial Genetics. St Louis:Mosby 1976; 156-193,

11. Nei JC, Fretorius JA, Weher A. Amelogenesis imperfecta. IntJ Periodontics Restorative Dent 1997; 17:479-483.

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