C L I N I C A L P R A C T I C E I CASE RE PO RT

Treatment of enamel hypoplasiain a patient with Usher syndromeVictor Alonso de la Peña, PhD, MD, DDS; Martín Caserío Valea, DDS

sher syndrome (USH) is a group of auto-somal recessive diseases that are char-

I acterized by retinitis pigmentosa withsensorineural hearing loss. It is the

leading cause of deaf-hlindness, and its preva-lence varies from 3.0 in 100,000 people in theScandinavian population to 4.4 in 100,000people in the U.S. population.'

There are three types of USH. USH type I(USHl) is characterized by congenital, severe orprofound hearing loss, vestibular dysfunctionand retinitis pigmentosa that initiates duringchildhood. USH type II (USH2) is characterizedby congenital, moderate or profound hearingloss and normal vestihular function, as well asdevelopment of retinitis pigmentosa after child-hood. USH type III (USH3) is characterized byprogressive hearing loss and a variahle age ofonset of retinal degeneration.^ There is exten-sive genetic and clinical heterogeneity inpatients with USH.-̂ Seven genetic loci havebeen identified for analyzing USHl, three gene-tic loci have been identified for USH2 and onegenetic locus has been identified for USH3.''

Amelogenesis imperfecta is a clinically and

Background. Usher syndrome (USH) is a group ofautosomal recessive diseases characterized by theassociation of retinitis pigmentosa with sensorineuralhearing loss. There are three types of USH. In addi-tion, in people with USH and hypoplasia, the thicknessof the enamel is reduced.Case Description. The authors describe a case of apatient with USH type II associated with severe en-amel hypoplasia and multiple unerupted teeth. Theauthors placed direct composite crowns and extractedseverely affected and impacted molars.Clinical Implications. There is little informationavailable on the oral pathologies of USH. Because theauthors did not know how the patient's conditionwould progress and the patient still was growing, theauthors treated the patient conservatively by placingdirect composite crowns. The treatment has met bothesthetic and functional expectations for 10 years.Key Words. Composites; dental veneers; permanentdental restorations; amelogenesis imperfecta; Ushersyndrome.JADA 2011;142(8):938-941.

Dr. de la Pena is an associate professor. School of Dentistry, University of Santiago de Compostela, Dr. •ftixeiro 11. 4 dcha.. 15701 Santiago de CompostelaA Coruna, Spain, e-mail "dentalinvestigation@yahoo.es". Address reprint requests to Dr. de la Peña.Dr. Caserío Valea is a postgraduate dental student. School of Dentistry, University of Santiago de Compostela, A Coruna, Spain.

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genetically heterogeneous disorder that affectsthe enamel of the primary and permanent teeth.Cases of amelogenesis imperfecta can he classi-fied into three groups: hypoplasia, hypocalcifica-tion and hypomaturation. The prevalence ofamelogenesis imperfecta varies according to thepopulation, ranging from one in 700 people in astudy on the Swedish population to one in14,000 in a study of the U.S. population.^' Hypo-plasia is characterized by reduced enamel thick-ness of varying degrees, as well as pits andother irregularities, although the hardness andtransparency of the enamel remain intact.'** Wefound one study in the literature whose authorsdescrihed a patient who had USH and enamelhypoplasia.^

CASE REPORTIn 1994, one of the authors (V.A.P.) examined a16-year-old boy in his private clinic (Clinica Dr.Victor Alonso de la Peña, Santiago de Com-postela, A Coruña, Spain). The patient hadreceived diagnoses of USH2, moderate sen-sorineural hypoacusis, normal vestihular func-tion and developing retinitis pigmentosa. Wefound that the patient had nine primary teeth(teeth nos. A, B, C, H, J, K, M, R and T). All ofhis permanent incisors, as well as the maxillaryleft first premolar and both mandihular firstpremolars, had erupted. We ohserved general-ized hypoplasia both on the primary teeth andon the permanent teeth (except for the primarycanines), with thin enamel and almost noenamel at the occlusal contact area on all of theteeth (Figure 1). We did not see any alterationsin the oral mucosa or pathology of the temporo-mandihular joint.

Radiographs showed that the canines andpermanent premolars (except for tooth no. 29)were well positioned hut had not erupted, andthe molars were retained. Both the molars andpremolars had alterations of the crown thatwere compatihle with severe hypoplasia; theenamel could not he observed.

The patient came to the clinic for esthetictreatment to hide the hypoplasia of his anteriorteeth. We created full crowns by using resin-based composite and strip crowns (Frasaco,Franz Sachs, Tettnang, Germany) for thematrix. All of the treatment was carried out inthe dental clinic, and the patient received localanesthetic when necessary.

We selected a suitahle strip crown and re-moved restorations from some of the maxillarycentral incisors. We used phosphoric acid to etchthe teeth and then applied adhesive (Prime &Bond 2.0, Dentsply De Trey, Konstanz, Ger-

%

mSÊÊÊm

Figure 1. A. A panoramic radiograph from 1994 showing theprimary and permanent canines, premolars and molars, all ofwhich had reduced enamel thickness. B. A clinical photographfrom 1994 showing severe hypoplasia on all of the teeth and thattooth no. 9 had been restored.

Figure 2. A clinical photograph from 1994 showing restoredteeth nos. 8 and 9. The fit and shape of the strip crown can beseen on tooth no. 9.

many) to all remaining exposed tooth tissue. Wefilled the crowns with composite (Spectrum TPHcomposite, Dentsply De Trey) and placed themon the teeth. We removed excess composite andpolymerized the whole restoration. We used anexplorer to remove the strip crown, and then wepolished and esthetically recontoured all of therestoration.

We used this technique to treat the maxillaryand mandihular central incisors (Figure 2).After we saw how positive the results were, wedecided to use this technique to treat teeth nos.5, 12, 27, 28 and 29.

Since 1994, the patient received additional

ABBREVIATION KEY. USH: Usher syndrome. USHl:Usher syndrome type I. USH2: Usher syndrome typeII. USH3: Usher syndrome type III.

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Figure 3. A. A panoramic radiograph obtained in 1996 showsthat strip crowns were placed on the permanent incisors. B. A pan-oramic radiograph obtained in 2009 shows the treatment thathad been performed between 1996 and 2009 (endodontictherapy in teeth nos. 5, 12, 13, 22, 27, 28 and 29; compositecrowns placed on teeth nos. 5, 12, 27, 28 and 29; porcelain-fused-to-metal crowns placed on teeth nos. 13, 21 and 22).

Figure 4. Clinical photograph of the composite crowns placed onall of the permanent teeth after 15 years.

dental treatment. We extracted teeth nos. 19and 30 because the patient had mandibularpain, and radiographs showed that the crownsof these unerupted teeth were almost com-pletely missing. Tooth no. 20 had severe peri-apical pathology, so we extracted it. Because ofmobility, we also extracted primary teeth (nos.A, B, J, M and R) that still were present. Afterteeth nos. 5, 12, 13, 22, 27, 28 and 29 erupted,pulp pathologies appeared in them, and we per-formed endodontic procedures on these teeth.We performed an apicoectomy on tooth no. 28.We placed porcelain-fused-to-metal crowns onteeth nos. 13, 21 and 22.

The patient received no further dental treat-ment after 2007. Radiographs from 1996 and2009 and the clinical progress of the restora-

tions are shown in Figures 3 and 4, respectively.The second and third mandibular molars re-mained impacted. In the maxilla, the molars,canines and right second premolar had noterupted. As the patient was asymptomatic, notreatment was required for the unerupted teeth.

DISCUSSIONMany patients with hearing impairments,visual impairments or both have reported thatthey are not informed about their disease, treat-ment options and prognosis properly.'' A varietyof factors can affect these patients'impairments,making it necessary for clinicians to treat pa-tients in an individualized manner." These fac-tors include the patient's age, how long thepatient has had the impairment, the severity ofthe impairment (slight, moderate, serious, pro-found), any associated problems (learning diffi-culties), communication skills and preferences,family issues (parental hearing impairmentsand attitude) and type of education (oral, bilin-gual, integrated, special). The minor communi-cation problems caused by our patient's progres-sive hearing loss and progressive blindnesswere resolved by the patient's guardian's beingpresent during the treatment to help aid com-munication between the patient and theclinician.

There is little information regarding the oralpathologies of USH. The authors of only onearticle have associated enamel hypoplasia withUSH.' The authors of two other articles asso-ciate hypoacusis with enamel hypoplasia andblindness, but they made no specific reference toUSH." «An eight-year-old patient with USHland defects in the enamel is mentioned inanother article, but its authors did not considerhypoplasia, because only the occlusal surfaces ofthe affected teeth had hypoplastic enamel.**

In addition, hypoplasia has been associatedwith Seckel syndrome"' or tricho-dento-osseoussyndrome." Taurodontism was associated withboth of these syndromes.

Amelogenesis imperfecta has been treatedwith indirect restorations such as veneers orporcelain crowns,'^"* although the investigatorsof some studies used composite veneers, whichis a more conservative treatment.'^'^^

Because we did not know how the patient'scondition would progress and the patient still wasgrowing, we chose to treat the patient conserva-tively by placing direct composite crowns so asnot to eliminate any dental structure and not toexclude other types of treatment. Another optionwe used for teeth nos. 13, 21 and 22 was to placeporcelain crowns on all the permanent teeth.

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As a result of the extractions and the impac-tion of the permanent molars, the patient couldhave had limited masticatory function. To avoidthis outcome, the patient and his parentsdecided against his undergoing the extractionsand prolonged restorative treatment.

CONCLUSION

Across 10 years, the treatment met our and thepatient's esthetic and functional expectations. •

Disclosure. Drs. de la Peña and Caserío Valea did not report anydisclosures.

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