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A follow-up study of orbital prostheses supported by dental implants
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JOHN BEUMER III
8. '
9.
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11.
Mitteilungen Deutsche Gesellschaft ffir Plastische und WiederhersteUungschirurgie e. V. 8:28-32, 1996 Betz Th, Reuther JF, Bill J: Klinische Nachuntersuchung enossaler Bone-Lock-Implantate unter besonderer Beriicksichtigung der periimplantiiren Gewebe. Eine Studie fiber 5 Jahre. Dtsch Z Mund Kiefer GesichtsChir 19:35, 1995 Kov4cs A: The effect of different transplanted soft tissues on bone resorption around loaded endosseous implants in patients after oral tumor surgery. Int J Oral Maxinofac Implants 13:554, 1998 ReutherJ, Thull R, Steveling H: Development of a new implant system (BONE-LOCK). Conception and scientific fundamentals. Leibinger BONE-LOCKEndosseous Implants 05/1991 Kov~cs A, Christ H: Erste Erfahrungen mit dem BONE-LOCKImplantat-System bei der prothetischen Versorgung nach Resek-
J Oral Maxillofac Surg
- - V
12.
13. 14.
15.
tion yon Mundh6hlentumoren. Z Zahniirztl Implantol 9:19, 1993 Jacobsson M, Tjellstr6m A, Fine L, et al: A retrospective study of osseointegrated skin-penetrating titanium fixtures used for retaining facial prostheses. Int J Oral Maxillofac Implants 7:523, 1992 Parel SM, Tjellstr6m A: The United States and Swedish experience with osseointegration and facial prostheses. Int J Oral Maxillofac Implants 6:75, 1991 Wolfaardt JF, Wilkes GH, Pare1 SM, et al: Craniofacial osseointegration: The Canadian experience. Int J Oral Maxillofac Implants 8:197, 1993 Beumer J, Roumanas E, Nishimura R: Advances in oseointegrated implants for dental and facial rehabilitation following major head and neck surgery. Semin Surg Oncol 11:200, 1995
m
58:23, 2000
Discussion A Follow-up Study of Orbital Prostheses Supported by Dental Implants J o h n B e u m e r III, DDS, MS Professorand Chair, Division of Advanced Prosthodontics, Biomaterials, and Hospital Dentistry, UCLA School of Dentistry, LosAngeles, California The long-term success rates o f craniofacial implants o f 3 and 4 m m in length placed in the frontal b o n e and around the orbit have b e e n disappointing, especially w h e n the sites have b e e n irradiated. 1,2 Perhaps the longer implants used in this study will be m o r e successful, but the p e r i o d o f follow-up is too short to allow for such a conclusion. It should b e n o t e d that m o s t failures in the previously cited reports o c c u r r e d late (after 3 years) and w e r e associated w i t h c o m p r o m i s e d peri-implant hygiene. In t h e s e reports, m o s t o f the patients w e r e elderly, and adequate implant hygiene was not consistently maintained. The a m o u n t o f debris on the a b u t m e n t s was m u c h greater in the orbital implant patients than in patients w i t h craniofacial implants placed in the floor of the n o s e or in the auricular region. 2 There may be several reasons for this p r o b l e m . Monocular vision and the associated c o m p r o m i s e in d e p t h p e r c e p t i o n may r e d u c e patients' ability to visualize their defects, manipulate the hygiene aids, and assess the quality of their hygiene. In addition, the manual dexterity of s o m e older patients may b e inadequate to achieve the level o f hygiene required to maintain healthy peri-implant tissues. The effect of the coating layer o f titanium-zirconium oxide o n the a b u t m e n t s used by the authors is difficult to assess. The skin reactions r e c o r d e d around t h e s e implants w e r e similar to those r e c o r d e d around implants using conventional titanium a b u t m e n t cylinders.l The authors n o t e that o n e o f their patients (patient 9) lost an implant b e c a u s e o f "load stress." It is unclear h o w they
c a m e to this conclusion, because the loads placed o n implants used to retain a facial prosthesis are considerably less than the loads delivered to implants retaining or s u p p o r t i n g an oral prosthesis. I w o u l d suggest that o t h e r factors may b e m o r e i m p o r t a n t - - i n f l a m m a t o r y reactions around the implants or p e r h a p s the b l o o d supply to the b o n e at t h e s e sites is inadequate to maintain the boneimplant interface. The p e r i o s t e u m in the supraorbital area is thin and atrophic, and multiple elevations o f the p e r i o s t e u m associated w i t h t u m o r resection or implant p l a c e m e n t may further c o m p r o m i s e its vasculature. In addition, b o n e sites in the orbit are heavily c o m p a c t e d , w i t h little or n o marrow, and may lack the o s t e o g e n i c s t e m cells and b l o o d supply necessary to create and maintain an adequate bone-implant interface. The authors r e p o r t n o e x p e r i e n c e in irradiated patients. However, it is important to n o t e that a r e c e n t report s e e m s to indicate that in frontal b o n e sites irradiated to a level of 4,500 to 6,000 cGy, the success rates are very poor. 1 Consequently, w e are not as enthusiastic as the authors about r e c o m m e n d i n g implants for r e t e n t i o n o f orbital-facial prostheses. Hygiene p r o c e d u r e s are difficult to e x e c u t e effectively, leading to unpredictable success rates. W e believe that orbital implants should only be placed in patients w h o u n d e r s t a n d the risk o f failure and the difficulty in maintaining p r o p e r implant hygiene.
References 1. Nishimura R, Roumans E, Moy P, et al: Osseointegrated implants and orbital defects: UCLA experience. J Prosthet Dent 79:304, 1998 2. Beumer J, Ma T, Marunick M, et al: Restoration of facial defects: Etiology, disability and rehabilitation, in Beumer J, Curtis T, Marunick M (eds): Maxillofacial Rehabilitation. St Louis, MO, Ishiyuku Euro America, 1996, pp 436-449
JOHN BEUMER III
8. '
9.
10.
11.
Mitteilungen Deutsche Gesellschaft ffir Plastische und WiederhersteUungschirurgie e. V. 8:28-32, 1996 Betz Th, Reuther JF, Bill J: Klinische Nachuntersuchung enossaler Bone-Lock-Implantate unter besonderer Beriicksichtigung der periimplantiiren Gewebe. Eine Studie fiber 5 Jahre. Dtsch Z Mund Kiefer GesichtsChir 19:35, 1995 Kov4cs A: The effect of different transplanted soft tissues on bone resorption around loaded endosseous implants in patients after oral tumor surgery. Int J Oral Maxinofac Implants 13:554, 1998 ReutherJ, Thull R, Steveling H: Development of a new implant system (BONE-LOCK). Conception and scientific fundamentals. Leibinger BONE-LOCKEndosseous Implants 05/1991 Kov~cs A, Christ H: Erste Erfahrungen mit dem BONE-LOCKImplantat-System bei der prothetischen Versorgung nach Resek-
J Oral Maxillofac Surg
- - V
12.
13. 14.
15.
tion yon Mundh6hlentumoren. Z Zahniirztl Implantol 9:19, 1993 Jacobsson M, Tjellstr6m A, Fine L, et al: A retrospective study of osseointegrated skin-penetrating titanium fixtures used for retaining facial prostheses. Int J Oral Maxillofac Implants 7:523, 1992 Parel SM, Tjellstr6m A: The United States and Swedish experience with osseointegration and facial prostheses. Int J Oral Maxillofac Implants 6:75, 1991 Wolfaardt JF, Wilkes GH, Pare1 SM, et al: Craniofacial osseointegration: The Canadian experience. Int J Oral Maxillofac Implants 8:197, 1993 Beumer J, Roumanas E, Nishimura R: Advances in oseointegrated implants for dental and facial rehabilitation following major head and neck surgery. Semin Surg Oncol 11:200, 1995
m
58:23, 2000
Discussion A Follow-up Study of Orbital Prostheses Supported by Dental Implants J o h n B e u m e r III, DDS, MS Professorand Chair, Division of Advanced Prosthodontics, Biomaterials, and Hospital Dentistry, UCLA School of Dentistry, LosAngeles, California The long-term success rates o f craniofacial implants o f 3 and 4 m m in length placed in the frontal b o n e and around the orbit have b e e n disappointing, especially w h e n the sites have b e e n irradiated. 1,2 Perhaps the longer implants used in this study will be m o r e successful, but the p e r i o d o f follow-up is too short to allow for such a conclusion. It should b e n o t e d that m o s t failures in the previously cited reports o c c u r r e d late (after 3 years) and w e r e associated w i t h c o m p r o m i s e d peri-implant hygiene. In t h e s e reports, m o s t o f the patients w e r e elderly, and adequate implant hygiene was not consistently maintained. The a m o u n t o f debris on the a b u t m e n t s was m u c h greater in the orbital implant patients than in patients w i t h craniofacial implants placed in the floor of the n o s e or in the auricular region. 2 There may be several reasons for this p r o b l e m . Monocular vision and the associated c o m p r o m i s e in d e p t h p e r c e p t i o n may r e d u c e patients' ability to visualize their defects, manipulate the hygiene aids, and assess the quality of their hygiene. In addition, the manual dexterity of s o m e older patients may b e inadequate to achieve the level o f hygiene required to maintain healthy peri-implant tissues. The effect of the coating layer o f titanium-zirconium oxide o n the a b u t m e n t s used by the authors is difficult to assess. The skin reactions r e c o r d e d around t h e s e implants w e r e similar to those r e c o r d e d around implants using conventional titanium a b u t m e n t cylinders.l The authors n o t e that o n e o f their patients (patient 9) lost an implant b e c a u s e o f "load stress." It is unclear h o w they
c a m e to this conclusion, because the loads placed o n implants used to retain a facial prosthesis are considerably less than the loads delivered to implants retaining or s u p p o r t i n g an oral prosthesis. I w o u l d suggest that o t h e r factors may b e m o r e i m p o r t a n t - - i n f l a m m a t o r y reactions around the implants or p e r h a p s the b l o o d supply to the b o n e at t h e s e sites is inadequate to maintain the boneimplant interface. The p e r i o s t e u m in the supraorbital area is thin and atrophic, and multiple elevations o f the p e r i o s t e u m associated w i t h t u m o r resection or implant p l a c e m e n t may further c o m p r o m i s e its vasculature. In addition, b o n e sites in the orbit are heavily c o m p a c t e d , w i t h little or n o marrow, and may lack the o s t e o g e n i c s t e m cells and b l o o d supply necessary to create and maintain an adequate bone-implant interface. The authors r e p o r t n o e x p e r i e n c e in irradiated patients. However, it is important to n o t e that a r e c e n t report s e e m s to indicate that in frontal b o n e sites irradiated to a level of 4,500 to 6,000 cGy, the success rates are very poor. 1 Consequently, w e are not as enthusiastic as the authors about r e c o m m e n d i n g implants for r e t e n t i o n o f orbital-facial prostheses. Hygiene p r o c e d u r e s are difficult to e x e c u t e effectively, leading to unpredictable success rates. W e believe that orbital implants should only be placed in patients w h o u n d e r s t a n d the risk o f failure and the difficulty in maintaining p r o p e r implant hygiene.
References 1. Nishimura R, Roumans E, Moy P, et al: Osseointegrated implants and orbital defects: UCLA experience. J Prosthet Dent 79:304, 1998 2. Beumer J, Ma T, Marunick M, et al: Restoration of facial defects: Etiology, disability and rehabilitation, in Beumer J, Curtis T, Marunick M (eds): Maxillofacial Rehabilitation. St Louis, MO, Ishiyuku Euro America, 1996, pp 436-449