Prosthetic rehabilitation of a patient with a unilateral cleft palate: A clinical report Mehmet Cudi Balkaya, DMD, PhD,a Huseyin Sultan,b Seda Erdem,c and Deniz Mutlud Faculty of Dentistry, Istanbul University, Istanbul, Turkey Cleft palate is a congenital disorder characterized by maxillary growth defect and dental anomalies. Its correction requires an interdisciplinary approach, which includes surgical, orthodontic, and prosthetic treatments. This clinical report describes the prosthetic management of a 19-year-old woman with a unilateral cleft palate defect that had not been closed completely with surgical repair. The deficient maxillary residual anterior ridge was restored with a tooth-supported overdenture that improved her facial appearance, speech, and masticatory functions. (J Prosthet Dent 2014;111:269-272) Cleft palate with or without cleft lip is the most common malformation of the orofacial region that results from delayed cell migration during palate development.1,2 The etiology of cleft palate is thought to include endogenous factors such as genetic disorders and exogenous factors such as environmental teratogens that can cause congenital defects. The environmental factors include cigarette smoke, systemic corticosteroid treatment, drug and lead pollution, viral effects, and maternal malnutrition.3-5 Increasing maternal age may increase the risk for cleft palate.6 Contemporary treatment concepts for cleft palate correction require early surgery at birth or in childhood. Speech and hearing functions can be improved by cleft closure before 2 years of age, because speech development in children from birth to 5 years of age is more rapid than that in any other phase of life.7-9 However, surgical treatment during the maxillary growth phase may result in residual ridge collapse followed by midface growth inhibition.7,10 Although mandibular growth is generally normal in patients with a cleft palate, adolescent or adult patients who are not treated for cleft closure at the optimal time experience posterior
a
reverse articulation, resulting from the collapse of the maxillary arch due to palatal muscle strain and scar retraction.11 The occlusal vertical dimension of these patients is consistent with that of individuals without clefts.12 However, the maxillary length decreases slightly because of anteroposterior growth defect, leaving the patients with insufficient facial support and a concave maxillary lip.13 Treatment options are arch expansion after residual ridge augmentation with autogenous graft from the iliac crest or tooth-supported or implant-supported partial fixed dental prostheses.14,15 However, the closure of a cleft palate is
Associate Professor, Department of Prosthetics. Doctoral student, Department of Prosthetics. c Doctoral student, Department of Prosthetics. d Doctoral student, Department of Prosthetics. b
Balkaya et al
1 Intraoral view.
more difficult in adults than in infants because of the wide cleft and irregular palate surface around the suture and the higher incidence of postoperative complications.16 If the cleft area is not closed completely with surgery, partial removable dental prostheses can be used to replace missing teeth and to compensate for tissue deficiencies that interrupt the continuity of the dental arch17; however, they rest on soft tissue and may cause irritation.15 In this instance, an overdenture supported entirely by the teeth may be a reasonable method of avoiding soft tissue injury in the cleft area. This
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Volume 111 Issue 4 denture combines the advantages of the partial removable prosthesis and fixed dental prosthesis because it minimizes the vertical movement of the denture base during masticatory function, facilitates access for cleaning of the abutment teeth, and, by providing maxillary lip support, improves facial appearance.18-22 Although several attachments are available to enhance the retention of the denture,23 telescopic crowns are preferred, because they increase the retention and stability of the denture and the splinting effect and axial load distribution on the abutment teeth.18,22,24-26 Zirconia can be considered for the primary crown because it has low plaque accumulation, is biocompatible with soft tissues, allows the elimination of the metal margin, and has low fracture rates.19,20 Pellecchia et al20 discussed the advantages of using a partial fixed dental prosthesis retained with a zirconia primary coping after the surgical closure of the cleft lip and palate. Retention of overdentures with telescopic crowns relates to the fit of the copings.21 An electroplated gold secondary coping is fabricated directly on the ceramic primary coping. This process ensures a precise fit of copings and a higher retention force than with cast copings because it eliminates the misfits that result from the impression, cast, and die systems.27,28 Retrospective studies on the use of ceramic and electroplated gold copings have reported long-term clinical survival rates.19,21 This clinical report presents the prosthetic rehabilitation of a patient with a unilateral cleft palate defect that surgical repair had not closed completely.
unilateral left reverse articulation due to a narrow maxillary arch. The maxillary left first premolar had rotated approximately 90 degrees from the normal position and exhibited enamel defects caused by developmental abnormalities (Fig. 1). Preoperative panoramic
radiography showed the oronasal fistula and showed that the maxillary incisors, maxillary right canine, and premolars were congenitally missing (Fig. 2). All treatment options were discussed with the patient, including surgical and prosthetic treatments. The
2 Preoperative panoramic radiograph.
3 Primary zirconia copings.
CLINICAL REPORT A 19-year-old woman with a unilateral cleft palate applied to the Faculty of Dentistry of Istanbul University for prosthetic treatment. The patient had undergone surgical closure of the oronasal fistula and cleft palate with bone grafting from the iliac crest 1 year previously. Clinical examination found a wide alveolar defect, multiple missing teeth in the cleft region, and posterior
The Journal of Prosthetic Dentistry
4 Secondary electroplated gold copings.
Balkaya et al
April 2014
271
5 Metal cast framework of overdenture. patient rejected an additional bone grafting procedure for the implant placement, because she did not want additional surgery. The overdenture that would be supported entirely by the teeth was required to prevent the denture movement and pressure on the cleft area and to replace missing hard and soft tissues. The zirconia primary and the electroplated gold secondary telescopic
crowns were proposed because of their suitable biologic, esthetic, and mechanical properties. The patient accepted the proposed denture and retainer option, and informed consent was obtained. The patient had mandibular anterior crowding resulting from insufficient arch space but declined an orthodontic appliance because of the lengthy treatment time. The lingually erupted mandibular
left lateral incisor was extracted to relieve crowding without orthodontic appliances, creating a space for natural alignment and providing an improvement in the position of the incisors. The right maxillary first molar and both left maxillary premolars were prepared as parallel as possible to each other with axial walls close to parallel. The margin preparation was completed with a rounded shoulder finish line located subgingivally on all surfaces with a diamond rotary cutting instrument (G141, 014; Medin, a.s.) in a highspeed handpiece. Impressions were made with polyvinyl siloxane material (Silagum; DMG ChemPharma Fabrik GmbH). The definitive cast was scanned by using software (DWOS; Dental Wings Inc) and a scanner (3Series; Yenadent, Yena Makina San Tic Ltd). The zirconia primary copings of 0.5-mm thickness and 4-degree taper were fabricated by a computer-aided design and computer-aided manufacturing (CAD/CAM) system (D43; Yenadent)
6 A, Completed definitive prosthesis. B, Tissue surfaces of completed prosthesis. C, Intraoral view of tooth-supported overdenture.
Balkaya et al
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Volume 111 Issue 4 from a presintered zirconia block (VITA InCeram YZ; VITA Zahnfabrik) and were evaluated for fit intraorally (Fig. 3). Pure gold (DeguDent GmbH) secondary copings of 0.25-mm thickness were fabricated on the zirconia copings by direct electroplating with the Solaris system (DeguDent GmbH). The zirconia primary copings were cemented to the abutment teeth with dual-polymerized self-adhesive resin (BisCem; Bisco Inc). The gold copings were placed on the zirconia copings (Fig. 4), and the denture framework cast with a Co-Cr alloy (Wironium; Bego, Herbst GmbH & Co KG) was evaluated for fit on the copings (Fig. 5). The framework was bonded intraorally to the gold copings with autopolymerizing adhesive resin (C&B Cement; Bisco). The definitive framework impression was made with the polyvinyl siloxane material (Silagum; DMG Chem-Pharma Fabrik GmbH) to fabricate a new definitive cast. The prosthesis was completed with veneering material (Solidex; Shofu Dental GmbH), acrylic resin denture teeth (Vitapan; VITA Zahnfabrik), and a heat-polymerized acrylic resin (Rapid Simplified; Vertex Dental) (Fig. 6A-C). The polished denture was inserted intraorally and evaluated for occlusion, retention, and stability. After oral hygiene instructions, the patient was recalled after 24 hours, 1 week, 1 month, 3 months, and 6 months for examination and cleaning of the denture. During the patient recall periods, no soft tissue injury, periodontal disease, or esthetic failures were observed, and the denture retention was satisfactory.
SUMMARY This clinical report describes the prosthetic rehabilitation of a patient with a unilateral cleft palate that had not been closed completely with surgical repair. The tissue deficiencies that had interrupted the continuity of the maxillary dental arch were restored with the entirely tooth-supported overdenture.
This denture improved the patient’s facial appearance, speech, and masticatory functions.
REFERENCES 1. Kummer AW. Cleft palate and craniofacial anomalies: effect on speech and resonance. 2nd ed. New York: Thomson Delmar Learning; 2008. p. 36-64. 2. Menezes R, Vieira AR. Dental anomalies as part of the cleft spectrum. Cleft Palate Craniofac J 2008;45:414-9. 3. Honein MA, Paulozzi LJ, Watkins ML. Maternal smoking and birth defects: validity of birth certificate data for effect estimation. Public Health Rep 2001;116:327-35. 4. Edwards MJ, Agho K, Attia J, Diaz P, Hayes T, Illingworth A, et al. Case-control study of cleft lip or palate after maternal use of topical corticosteroids during pregnancy. Am J Med Genet A 2003;120A:459-63. 5. Vinceti M, Rovesti S, Bergomi M, Calzolari E, Candela S, Campagna A, et al. Risk of birth defects in a population exposed to environmental lead pollution. Sci Total Environ 2001;278:23-30. 6. Bille C, Skytthe A, Vach W, Knudsen LB, Andersen AM, Murray JC, et al. Parent’s age and the risk of oral clefts. Epidemiology 2005;16:311-6. 7. Haapanen ML, Rantala SL. Correlation between the age at repair and speech outcome in patients with isolated cleft palate. Scand J Plast Reconstr Surg Hand Surg 1992;26:71-8. 8. Zhao S, Xu Y, Yin H, Zheng Q, Wang Y, Zhong T, et al. Incidence of postoperative velopharyngeal insufficiency in late palate repair. J Craniofac Surg 2012;23:1602-6. 9. Rohrich RJ, Love EJ, Byrd HS, Johns DF. Optimal timing of cleft palate closure. Plast Reconstr Surg 2000;106:413-21. 10. Denk MJ, Magee WP Jr. Cleft palate closure in the neonate: preliminary report. Cleft Palate Craniofac J 1996;33:57-61. 11. Oberoi S, Chigurupati R, Vargervik K. Morphologic and management characteristics of individuals with unilateral cleft lip and palate who required maxillary advancement. Cleft Palate Craniofac J 2008;45:42-9. 12. Will LA. Growth and development in patients with untreated clefts [review]. Cleft Palate Craniofac J 2000;37:523-6. 13. Daskalogiannakis J, Mercado A, Russell K, Hathaway R, Dugas G, Long RE Jr, et al. The Americleft study: an inter-center study of treatment outcomes for patients with unilateral cleft lip and palate part 3. Analysis of craniofacial form. Cleft Palate Craniofac J 2011;48:252-8. 14. Yang CJ, Pan XG, Qian YF, Wang GM. Impact of rapid maxillary expansion in unilateral cleft lip and palate patients after secondary alveolar bone grafting: review and case report. Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:e25-30. 15. Reisberg DJ. Dental and prosthodontic care for patients with cleft or craniofacial conditions [review]. Cleft Palate Craniofac J 2000;37:534-7.
The Journal of Prosthetic Dentistry
16. Morioka D, Yoshimoto S, Udagawa A, Ohkubo F, Yoshikawa A. Primary repair in adult patients with untreated cleft lip-cleft palate. Plast Reconstr Surg 2007;120: 1981-8. 17. Hickey AJ, Salter M. Prosthodontic and psychological factors in treating patients with congenital and craniofacial defects. J Prosthet Dent 2006;95:392-6. 18. Langer Y, Langer A. Tooth-supported telescopic prostheses in compromised dentitions: a clinical report. J Prosthet Dent 2000;84:129-32. 19. Zafiropoulos GG, Rebbe J, Thielen U, Deli G, Beaumont C, Hoffmann O. Zirconia removable telescopic dentures retained on teeth or implants for maxilla rehabilitation. Threeyear observation of three cases. J Oral Implantol 2010;36:455-65. 20. Pellecchia R, Kang KH, Hirayama H. Fixed partial denture supported by all-ceramic copings: a clinical report. J Prosthet Dent 2004;92:220-3. 21. Weigl P, Lauer HC. Advanced biomaterials used for a new telescopic retainer for removable dentures. J Biomed Mater Res 2000;53:337-47. 22. Mañes Ferrer JF, Martínez González A, Oteiza Galdón B, Bouazza Juanes K, Benet Iranzo F, Candel Tomás A. Telescopic crowns in adult case with lip and palate cleft: update on the etiology and management. Med Oral Patol Oral Cir Bucal 2006;11:E358-62. 23. Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed prosthodontics. 4th ed. St Louis: Elsevier; 2006. p. 649-80. 24. Weaver JD. Telescopic copings in restorative dentistry. J Prosthet Dent 1989;61: 429-33. 25. Akagawa Y, Seo T, Ohkawa S, Tsuru H. A new telescopic crown system using a soldered horizontal pin for removable partial dentures. J Prosthet Dent 1993;69: 228-31. 26. Ohkawa S, Okana H, Nagasawa T, Tsuru H. Changes in retention of various telescope crown assemblies over long-term use. J Prosthet Dent 1990;64:153-8. 27. Bayer S, Kraus D, Keilig L, Gölz L, Stark H, Enkling N. Wear of double crown systems: electroplated vs. casted female part. J Appl Oral Sci 2012;20:384-91. 28. Castilho AA, Kojima AN, Pereira SM, Vasconcellos DK, Itinoche MK, Faria R, et al. In vitro evaluation of the precision of working casts for implant-supported restoration with multiple abutments. J Appl Oral Sci 2007;15: 241-6. Corresponding author: Dr Mehmet Cudi Balkaya Department of Prosthetics, Faculty of Dentistry Istanbul University Millet St 34390 Istanbul TURKEY E-mail: [email protected] Copyright ª 2014 by the Editorial Council for The Journal of Prosthetic Dentistry.
Balkaya et al
a
reverse articulation, resulting from the collapse of the maxillary arch due to palatal muscle strain and scar retraction.11 The occlusal vertical dimension of these patients is consistent with that of individuals without clefts.12 However, the maxillary length decreases slightly because of anteroposterior growth defect, leaving the patients with insufficient facial support and a concave maxillary lip.13 Treatment options are arch expansion after residual ridge augmentation with autogenous graft from the iliac crest or tooth-supported or implant-supported partial fixed dental prostheses.14,15 However, the closure of a cleft palate is
Associate Professor, Department of Prosthetics. Doctoral student, Department of Prosthetics. c Doctoral student, Department of Prosthetics. d Doctoral student, Department of Prosthetics. b
Balkaya et al
1 Intraoral view.
more difficult in adults than in infants because of the wide cleft and irregular palate surface around the suture and the higher incidence of postoperative complications.16 If the cleft area is not closed completely with surgery, partial removable dental prostheses can be used to replace missing teeth and to compensate for tissue deficiencies that interrupt the continuity of the dental arch17; however, they rest on soft tissue and may cause irritation.15 In this instance, an overdenture supported entirely by the teeth may be a reasonable method of avoiding soft tissue injury in the cleft area. This
270
Volume 111 Issue 4 denture combines the advantages of the partial removable prosthesis and fixed dental prosthesis because it minimizes the vertical movement of the denture base during masticatory function, facilitates access for cleaning of the abutment teeth, and, by providing maxillary lip support, improves facial appearance.18-22 Although several attachments are available to enhance the retention of the denture,23 telescopic crowns are preferred, because they increase the retention and stability of the denture and the splinting effect and axial load distribution on the abutment teeth.18,22,24-26 Zirconia can be considered for the primary crown because it has low plaque accumulation, is biocompatible with soft tissues, allows the elimination of the metal margin, and has low fracture rates.19,20 Pellecchia et al20 discussed the advantages of using a partial fixed dental prosthesis retained with a zirconia primary coping after the surgical closure of the cleft lip and palate. Retention of overdentures with telescopic crowns relates to the fit of the copings.21 An electroplated gold secondary coping is fabricated directly on the ceramic primary coping. This process ensures a precise fit of copings and a higher retention force than with cast copings because it eliminates the misfits that result from the impression, cast, and die systems.27,28 Retrospective studies on the use of ceramic and electroplated gold copings have reported long-term clinical survival rates.19,21 This clinical report presents the prosthetic rehabilitation of a patient with a unilateral cleft palate defect that surgical repair had not closed completely.
unilateral left reverse articulation due to a narrow maxillary arch. The maxillary left first premolar had rotated approximately 90 degrees from the normal position and exhibited enamel defects caused by developmental abnormalities (Fig. 1). Preoperative panoramic
radiography showed the oronasal fistula and showed that the maxillary incisors, maxillary right canine, and premolars were congenitally missing (Fig. 2). All treatment options were discussed with the patient, including surgical and prosthetic treatments. The
2 Preoperative panoramic radiograph.
3 Primary zirconia copings.
CLINICAL REPORT A 19-year-old woman with a unilateral cleft palate applied to the Faculty of Dentistry of Istanbul University for prosthetic treatment. The patient had undergone surgical closure of the oronasal fistula and cleft palate with bone grafting from the iliac crest 1 year previously. Clinical examination found a wide alveolar defect, multiple missing teeth in the cleft region, and posterior
The Journal of Prosthetic Dentistry
4 Secondary electroplated gold copings.
Balkaya et al
April 2014
271
5 Metal cast framework of overdenture. patient rejected an additional bone grafting procedure for the implant placement, because she did not want additional surgery. The overdenture that would be supported entirely by the teeth was required to prevent the denture movement and pressure on the cleft area and to replace missing hard and soft tissues. The zirconia primary and the electroplated gold secondary telescopic
crowns were proposed because of their suitable biologic, esthetic, and mechanical properties. The patient accepted the proposed denture and retainer option, and informed consent was obtained. The patient had mandibular anterior crowding resulting from insufficient arch space but declined an orthodontic appliance because of the lengthy treatment time. The lingually erupted mandibular
left lateral incisor was extracted to relieve crowding without orthodontic appliances, creating a space for natural alignment and providing an improvement in the position of the incisors. The right maxillary first molar and both left maxillary premolars were prepared as parallel as possible to each other with axial walls close to parallel. The margin preparation was completed with a rounded shoulder finish line located subgingivally on all surfaces with a diamond rotary cutting instrument (G141, 014; Medin, a.s.) in a highspeed handpiece. Impressions were made with polyvinyl siloxane material (Silagum; DMG ChemPharma Fabrik GmbH). The definitive cast was scanned by using software (DWOS; Dental Wings Inc) and a scanner (3Series; Yenadent, Yena Makina San Tic Ltd). The zirconia primary copings of 0.5-mm thickness and 4-degree taper were fabricated by a computer-aided design and computer-aided manufacturing (CAD/CAM) system (D43; Yenadent)
6 A, Completed definitive prosthesis. B, Tissue surfaces of completed prosthesis. C, Intraoral view of tooth-supported overdenture.
Balkaya et al
272
Volume 111 Issue 4 from a presintered zirconia block (VITA InCeram YZ; VITA Zahnfabrik) and were evaluated for fit intraorally (Fig. 3). Pure gold (DeguDent GmbH) secondary copings of 0.25-mm thickness were fabricated on the zirconia copings by direct electroplating with the Solaris system (DeguDent GmbH). The zirconia primary copings were cemented to the abutment teeth with dual-polymerized self-adhesive resin (BisCem; Bisco Inc). The gold copings were placed on the zirconia copings (Fig. 4), and the denture framework cast with a Co-Cr alloy (Wironium; Bego, Herbst GmbH & Co KG) was evaluated for fit on the copings (Fig. 5). The framework was bonded intraorally to the gold copings with autopolymerizing adhesive resin (C&B Cement; Bisco). The definitive framework impression was made with the polyvinyl siloxane material (Silagum; DMG Chem-Pharma Fabrik GmbH) to fabricate a new definitive cast. The prosthesis was completed with veneering material (Solidex; Shofu Dental GmbH), acrylic resin denture teeth (Vitapan; VITA Zahnfabrik), and a heat-polymerized acrylic resin (Rapid Simplified; Vertex Dental) (Fig. 6A-C). The polished denture was inserted intraorally and evaluated for occlusion, retention, and stability. After oral hygiene instructions, the patient was recalled after 24 hours, 1 week, 1 month, 3 months, and 6 months for examination and cleaning of the denture. During the patient recall periods, no soft tissue injury, periodontal disease, or esthetic failures were observed, and the denture retention was satisfactory.
SUMMARY This clinical report describes the prosthetic rehabilitation of a patient with a unilateral cleft palate that had not been closed completely with surgical repair. The tissue deficiencies that had interrupted the continuity of the maxillary dental arch were restored with the entirely tooth-supported overdenture.
This denture improved the patient’s facial appearance, speech, and masticatory functions.
REFERENCES 1. Kummer AW. Cleft palate and craniofacial anomalies: effect on speech and resonance. 2nd ed. New York: Thomson Delmar Learning; 2008. p. 36-64. 2. Menezes R, Vieira AR. Dental anomalies as part of the cleft spectrum. Cleft Palate Craniofac J 2008;45:414-9. 3. Honein MA, Paulozzi LJ, Watkins ML. Maternal smoking and birth defects: validity of birth certificate data for effect estimation. Public Health Rep 2001;116:327-35. 4. Edwards MJ, Agho K, Attia J, Diaz P, Hayes T, Illingworth A, et al. Case-control study of cleft lip or palate after maternal use of topical corticosteroids during pregnancy. Am J Med Genet A 2003;120A:459-63. 5. Vinceti M, Rovesti S, Bergomi M, Calzolari E, Candela S, Campagna A, et al. Risk of birth defects in a population exposed to environmental lead pollution. Sci Total Environ 2001;278:23-30. 6. Bille C, Skytthe A, Vach W, Knudsen LB, Andersen AM, Murray JC, et al. Parent’s age and the risk of oral clefts. Epidemiology 2005;16:311-6. 7. Haapanen ML, Rantala SL. Correlation between the age at repair and speech outcome in patients with isolated cleft palate. Scand J Plast Reconstr Surg Hand Surg 1992;26:71-8. 8. Zhao S, Xu Y, Yin H, Zheng Q, Wang Y, Zhong T, et al. Incidence of postoperative velopharyngeal insufficiency in late palate repair. J Craniofac Surg 2012;23:1602-6. 9. Rohrich RJ, Love EJ, Byrd HS, Johns DF. Optimal timing of cleft palate closure. Plast Reconstr Surg 2000;106:413-21. 10. Denk MJ, Magee WP Jr. Cleft palate closure in the neonate: preliminary report. Cleft Palate Craniofac J 1996;33:57-61. 11. Oberoi S, Chigurupati R, Vargervik K. Morphologic and management characteristics of individuals with unilateral cleft lip and palate who required maxillary advancement. Cleft Palate Craniofac J 2008;45:42-9. 12. Will LA. Growth and development in patients with untreated clefts [review]. Cleft Palate Craniofac J 2000;37:523-6. 13. Daskalogiannakis J, Mercado A, Russell K, Hathaway R, Dugas G, Long RE Jr, et al. The Americleft study: an inter-center study of treatment outcomes for patients with unilateral cleft lip and palate part 3. Analysis of craniofacial form. Cleft Palate Craniofac J 2011;48:252-8. 14. Yang CJ, Pan XG, Qian YF, Wang GM. Impact of rapid maxillary expansion in unilateral cleft lip and palate patients after secondary alveolar bone grafting: review and case report. Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:e25-30. 15. Reisberg DJ. Dental and prosthodontic care for patients with cleft or craniofacial conditions [review]. Cleft Palate Craniofac J 2000;37:534-7.
The Journal of Prosthetic Dentistry
16. Morioka D, Yoshimoto S, Udagawa A, Ohkubo F, Yoshikawa A. Primary repair in adult patients with untreated cleft lip-cleft palate. Plast Reconstr Surg 2007;120: 1981-8. 17. Hickey AJ, Salter M. Prosthodontic and psychological factors in treating patients with congenital and craniofacial defects. J Prosthet Dent 2006;95:392-6. 18. Langer Y, Langer A. Tooth-supported telescopic prostheses in compromised dentitions: a clinical report. J Prosthet Dent 2000;84:129-32. 19. Zafiropoulos GG, Rebbe J, Thielen U, Deli G, Beaumont C, Hoffmann O. Zirconia removable telescopic dentures retained on teeth or implants for maxilla rehabilitation. Threeyear observation of three cases. J Oral Implantol 2010;36:455-65. 20. Pellecchia R, Kang KH, Hirayama H. Fixed partial denture supported by all-ceramic copings: a clinical report. J Prosthet Dent 2004;92:220-3. 21. Weigl P, Lauer HC. Advanced biomaterials used for a new telescopic retainer for removable dentures. J Biomed Mater Res 2000;53:337-47. 22. Mañes Ferrer JF, Martínez González A, Oteiza Galdón B, Bouazza Juanes K, Benet Iranzo F, Candel Tomás A. Telescopic crowns in adult case with lip and palate cleft: update on the etiology and management. Med Oral Patol Oral Cir Bucal 2006;11:E358-62. 23. Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed prosthodontics. 4th ed. St Louis: Elsevier; 2006. p. 649-80. 24. Weaver JD. Telescopic copings in restorative dentistry. J Prosthet Dent 1989;61: 429-33. 25. Akagawa Y, Seo T, Ohkawa S, Tsuru H. A new telescopic crown system using a soldered horizontal pin for removable partial dentures. J Prosthet Dent 1993;69: 228-31. 26. Ohkawa S, Okana H, Nagasawa T, Tsuru H. Changes in retention of various telescope crown assemblies over long-term use. J Prosthet Dent 1990;64:153-8. 27. Bayer S, Kraus D, Keilig L, Gölz L, Stark H, Enkling N. Wear of double crown systems: electroplated vs. casted female part. J Appl Oral Sci 2012;20:384-91. 28. Castilho AA, Kojima AN, Pereira SM, Vasconcellos DK, Itinoche MK, Faria R, et al. In vitro evaluation of the precision of working casts for implant-supported restoration with multiple abutments. J Appl Oral Sci 2007;15: 241-6. Corresponding author: Dr Mehmet Cudi Balkaya Department of Prosthetics, Faculty of Dentistry Istanbul University Millet St 34390 Istanbul TURKEY E-mail: [email protected] Copyright ª 2014 by the Editorial Council for The Journal of Prosthetic Dentistry.
Balkaya et al
