Rehabilitation of a patient with amelogenesis imperfecta using allceramic crowns: A clinical report Hakimeh Siadat, DDS, MSc,a Marzieh Alikhasi, DDS, MSc,b and Ali Mirfazaelian, DDS, MScc School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran This article presents a patient with amelogenesis imperfecta rehabilitated with all-ceramic crowns following surgical and orthodontic intervention. The 6-year evaluation of the esthetics and function of the restorations showed evidence of isolated pulp exposure and crown fractures in the posterior areas. (J Prosthet Dent 2007; 98: 85-88.)
Genetic defects of the enamel are the most frequent congenital anomalies of dental hard tissues.1 Amelogenesis imperfecta (AI) is a diverse group of hereditary conditions that affects the quality and quantity of dental enamel. Different inheritance patterns, including autosomal dominant, autosomal recessive, and X-linked, have been suggested in the literature.2 The anatomic and histologic features of the various phenotypes include either reduced enamel thickness (hypoplasia) or decreased mineralization (hypomineralization including hypomaturation and hypocalcification subtypes).3 Dental features associated with AI include enamel deficiencies, pulpal calcification, taurodontism, root malformations, failed tooth eruption, impaction of permanent teeth, progressive root and crown resorption, congenitally missing teeth, and anterior and posterior open articulations.4 Factors that adversely influence oral health and prosthetic treatment prognosis include poor oral hygiene and mouth breathing with associated gingivitis and gingival hyperplasia.5 The use of all-ceramic restorations has increased because of their inher-
ent esthetics, excellent biocompatibility, and improved physical properties.6 It has been suggested that all-ceramic restorations should be bonded to tooth structure with adhesive resin cements to enhance fracture resistance of the restorations7,8 and the abutment tooth,9 and to prevent postoperative sensitivity.10 However, there is some evidence that adhesive cementation may not be necessary for long-term clinical success of aluminous porcelain or zirconia posterior crowns.11 Clinical studies have not yet compared the influence of different luting agents on the clinical performance of such restorations. When a reliable bond between the ceramic and tooth is established, the tooth may act as a supportive core to the ceramic material, although it has also been shown that metal cores might decrease the fracture probability of some all-ceramic crowns.8 All-ceramic coping materials, such as alumina and zirconia ceramics, are not sufficiently roughened by airborne-particle abrasion or etched with hydrofluoric acid, and do not sufficiently react with a silane coupling agent due to their low silica content.12 Solid sintered zirconia has sev-
eral potential advantages compared to other ceramic materials, including increased strength and toughness, decreased elastic modulus, and the possibility of undergoing transformation toughening.13 This is more important for posterior areas in the mouth, where the forces are greater than those of the anterior region.14 In these situations, the use of aluminous and zirconia cores and crowns, which have higher flexural strength than other all-ceramic materials, may be indicated.15-17 The clinician must carefully balance the esthetic needs of the patient, strength of the restoration, protection of the remaining teeth, and long-term prognosis of the treatment. This article presents a patient affected by AI who was rehabilitated with all-ceramic restorations with zirconium-oxide cores, and the 6-year follow-up results.
CLINICAL REPORT An 18-year-old woman was referred to the Department of Prosthodontics at Tehran University of Medical Science. A detailed medical, dental, and social history was obtained. The medical history and
Assistant Professor, Department of Prosthodontics and Implantology, Department of Dental Research. Assistant Professor, Department of Fixed Prosthodotics. c Assistant Professor, Department of Prosthodontics, Department of Dental Research. a
b
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Volume 98 Issue 2 general physical condition were unremarkable. The family history revealed that the patient’s parents were cousins and were not affected by AI, although her brother was affected by AI. The patient had not had any restorative treatment for esthetics before the consultation and indicated a desire to improve the appearance of her anterior teeth, which were discolored and had stained, pitted, and hypoplastic enamel (Fig. 1). The patient stated that her primary teeth were also discolored and did not report any parafunctional habits. Clinical and radiographic examination of the patient revealed short clinical crowns, occlusal wear with exposed dentin in the posterior areas, open anterior occlusion, high smile line,18 asymmetry of the gingival contours in the anterior maxillary teeth, and a retained radiopaque lesion around the apex of the mandibular left second premolar. The differential diagnosis included odontoma and bone sclerosis. The central incisors had received endodontic therapy and there was no radiographic evidence of caries (Fig. 2). The mandibular teeth were well aligned, but crowding of the anterior maxillary teeth was noticed, with a reverse horizontal overlap of the right lateral incisor tooth. The patient had acceptable oral hygiene; however, gingival hyperplasia and mild gingivitis were present, especially in the anterior maxilla. The patient was then re-
ferred to the Dental Anomalies Clinic of the Tehran University of Medical Sciences, with a tentative diagnosis of autosomal recessive AI. The right impacted third molars were extracted, and a histologic exam was performed to confirm the diagnosis. The diagnosis was hereditary hypoplastic-type amelogenesis imperfecta. Prior to treatment, diagnostic casts were obtained and mounted in a semi-adjustable articulator (Whip Mix 3000 Series; Whip Mix Corp, Louisville, Ky) using an ear-bow transfer and interocclusal record. The diagnostic waxing revealed insufficient interocclusal space for fixed prostheses. Accordingly, a treatment plan was developed with these aims: improving the malocclusion, restoring masticatory function, and improving the patient’s appearance with all-ceramic (In-Ceram Zirconia; VITA Zahnfabrik, Bad Sackingen, Germany) crowns. Clinical crown elongation was performed on both maxillary and mandibular teeth, and after a 6-week healing period, orthodontic therapy was initiated in the maxillary arch to correct the negative horizontal overlap of the right lateral incisor. All teeth responded normally to pulp sensibility tests. The teeth had rather large pulp chambers that would result in pulpal exposure of maxillary first molars and right lateral incisor teeth during preparation. Therefore, endodontic treatment was
1 Pretreatment view of teeth in occlusion.
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performed and custom cast gold (Degubond 4; DeguDent, Hanau, Germany) posts and cores were fabricated. Tooth preparation with a circumferential shoulder margin configuration was performed under local anesthesia, and provisional restorations were fabricated and cemented with noneugenol zinc oxide cement (TempBond NE; Kerr Corp, Orange, Calif ). Impressions were made with polyether impression material (Impregum F; 3M ESPE, St. Paul, Minn) using custom trays. In-Ceram zirconia cores (VITA Zahnfabrik) were fabricated by slip casting technique. Layering porcelain (Vitadur Alpha; VITA Zahnfabrik) was used to complete the all-ceramic crowns. The restorations were ultrasonically cleaned in distilled water for 10 minutes. The marginal fit and occlusion of the crowns was evaluated intraorally (Fig. 3), and the crowns were then cemented with dual-polymerizing resin cement (Enforce; Dentsply Caulk, Milford, Del) (Figs. 4 and 5). The patient was pleased with the result and was motivated to maintain her oral hygiene, as was assessed at the yearly recalls. At the 6-year follow up, mild gingivitis was present around the restored anterior teeth (Fig. 6). Radiographic findings indicated that there were periapical inflammatory changes associated with the mandibular first right and maxillary second right molars that required
2 Pretreatment panoramic radiograph.
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3 Posttreatment view of teeth in maximum intercuspation. 4 Posttreatment maxillary occlusal view.
5 Posttreatment mandibular occlusal view.
6 Anterior view of prostheses 6 years after insertion.
7 Panoramic radiograph demonstrating radiolucencies.
8 Occlusal view of fractured mandibular molar crowns.
subsequent endodontic therapy (Fig. 7). Lack of bonding of zirconia allceramic crowns to dentin may result in microleakage and subsequent pulp exposure. Clinical examination revealed that left mandibular first and second molar restorations were fractured (Fig. 8), and although repairing a fractured restoration can be a quick
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and practical short-term solution, the severity of the fractures indicated that replacement of the crowns was necessary. The authors hypothesize that the potential for lack of bonding of the In-Ceram system may have resulted in the crown fractures observed at the 6year recall. Although In-Ceram Zirconia (VITA Zahnfabrik) has higher flex-
ural strength, the authors determined that IPS Empress 2 (Ivoclar Vivadent, Amherst, NY) with adequate strength and good bonding properties would be a good option to restore the short prepared teeth with failed crowns. Thus, fractured crowns were replaced with IPS Empress 2 restorations.
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Volume 98 Issue 2 SUMMARY This clinical report describes the use of all-ceramic restorations for the rehabilitation of a patient with hypoplastic-type amelogenesis imperfecta. A combination of orthodontic treatment and periodontal surgery was performed as part of the prosthetic treatment plan to achieve acceptable occlusal and esthetic results.
REFERENCES 1. Aldred MJ, Savarirayan R, Crawford PJ. Amelogenesis imperfecta: a classification and catalogue for the 21st century. Oral Dis 2003;9:19-23. 2. Stephanopoulos G, Garefalaki ME, Lyroudia K. Genes and related proteins involved in amelogenesis imperfecta. J Dent Res 2005;84:1117-26. 3. Witkop CJ. Amelogenesis imperfecta, dentinogenesis imperfecta and dentin dysplasia revisited; problems in classification. J Oral Pathol 1988;17:547-53. 4. Williams WP, Becker LH. Amelogenesis imperfecta: functional and esthetic restoration of a severely compromised dentition. Quintessence Int 2000;31:397-403. 5. Rowley R, Hill FJ, Winter GB. An investigation of association between anterior open-
bite and amelogenesis imperfecta. Am J Orthod 1982;81:229-35. 6. Christensen GJ. Porcelain-fused-to-metal vs. nonmetal crowns. J Am Dent Assoc 1999;130:409-11. 7. Blatz MB. Long-term clinical success of all-ceramic posterior restorations. Quintessence Int 2002;33:415-26. 8. Malament KA, Socransky SS. Survival of Dicor glass-ceramic dental restorations over 16 years. Part III: effect of luting agent and tooth or tooth-substitute core structure. J Prosthet Dent 2001;86:511-9. 9. Burke FJ. The effect of variations in bonding procedure on fracture resistance of dentinbonded all-ceramic crowns. Quintessence Int 1995;26:293-300. 10. Sensat ML, Brackett WW, Meinberg TA, Beatty MW. Clinical evaluation of two adhesive composite cements for the suppression of dentinal cold sensitivity. J Prosthet Dent 2002;88:50-3. 11.Haselton DR, Diaz-Arnold AM, Hillis SL. Clinical assessment of high strength all-ceramic crowns. J Prosthet Dent 2000;83:396-401. 12.Kern M, Thompson VP. Bonding to glass infiltrated alumina ceramic: adhesive methods and their durability. J Prosthet Dent 1995;73:240-9. 13.Kosmac T, Oblak C, Jevnikar P, Funduk N, Marion L. The effect of surface grinding and sandblasting on flexural strength and reliability of Y-TZP zirconia ceramic. Dent Mater 1999;15:426-33. 14.Bakke M, Holm B, Jensen BL, Michler L,
Moller E. Unilateral, isometric bite force in 8-68-year-old women and men related to occlusal factors. Scand J Dent Res 1990;98:149-58. 15.Holand W, Schweiger M, Frank M, Rheinberger V. A comparison of the microstructure and properties of the IPS Empress 2 and the IPS Empress glass-ceramics. J Biomed Mater Res 2000;53:297-303. 16.Wagner WC, Chu TM. Biaxial flexural strength and indentation fracture toughness of three new dental core ceramics. J Prosthet Dent 1996;76:140-4. 17.Guazzato M, Albakry M, Swain MV, Ironside J. Mechanical properties of In-Ceram Alumina and In-Ceram Zirconia. Int J Prosthodont 2002;15:339-46. 18.Tjan AH, Miller GD, The JG. Some esthetic factors in a smile. J Prosthet Dent 1984;51:24-8. Corresponding author: Dr Hakimeh Siadat Department of Prosthodontics and Implantology School of Dentistry, Tehran University of Medical Sciences Ghods St, Enghelab St Tehran, 141555583 IRAN Fax: 9821-88737216 E-mail:
[email protected] Copyright © 2007 by the Editorial Council of The Journal of Prosthetic Dentistry.
Noteworthy Abstracts of the Current Literature Facial development, continuous tooth eruption, and mesial drift as compromising factors for implant placement Heij DG, Opdebeeck H, van Steenberghe D, Kokich VG, Belser U, Quirynen M. Int J Oral Maxillofac Implants 2006;21:867–78.
The replacement of teeth lost by children because of trauma can be an important indication for early implant therapy. Osseointegrated dental implants, like ankylosed teeth, alter position as growth-related changes occur within the jawbones (displacement, remodeling, mesial drift). Facial growth of the child and even of the adolescent, as well as the continuous eruption of the adjacent anterior teeth, create significant risk of a less favorable esthetic and/or functional outcome. For patients with a normal facial profile, the placement of an implant should be postponed until growth is complete. For patients with a short or long face type, further growth, especially the continuous eruption of adjacent teeth, creates a serious risk even after the age of 20 years, as illustrated by some recent clinical studies. This review aims to explain these phenomena and provides some recommendations for implant placement. Reprinted with permission of Quintessence Publishing.
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