- Email: [email protected]
Retention designs for bone-anchored facial prostheses
Retention J. J. Gary, William
designs DDS,a
Beaumont
for bone-anchored
and M. Donovan,
Army Medical
facial
prostheses
DDSb
Center, Fort Bliss, Tex.
A facial prosthesis can be retained by bone-anchored implants and by a retentive bar. Because tissue response is critical around the abutments, the retentive bar should be constructed so that it is comfortable, conveniently hygienic, and designed without compromising the contours of the prosthesis. (J PROSTHET DENT 1993;70:329-32.)
A.
facial prosthesis can be a possible solution for the patient with a facial defect that may not be corrected by surgical reconstruction. A prosthesis can be designed that fulfills the esthetic needs of the patient, but prosthesis retention may not be optimal. Skin adhesives can be used to retain the prosthesis but problems of retention, margin integrity, skin irritations, and prosthesis misalignment can still exist. The use of bone-anchored implants to retain a facial prosthesis can minimize retention problems’-* and provide a psychologically acceptable prosthesis. With the use of bone-anchored implants, optimal tissue health around the abutments is a primary concern. The reaction of the skin around skin-penetrating abutments can be graded according to the standards presented by Holgers et aL2 Optimal tissue health can be obtained by surgical modification of the tissue around abutments, adequate distance between the implants, good hygiene, and hygienic contours of the retentive bar. Minimal movement of the tissues around the abutments is accomplished by removal of the subcutaneous tissue approximately 10 mm around the implants during the second surgical stage. A skin graft may be needed to establish a zone free from hair at least 7 mm around the abutments.2T 5 Implants must be placed with sufficient distance from each other to permit hygiene of the skin around the abutments. Because tissue response is critical around the abutments, hygiene procedures should be facilitated by designing the retentive bar with minimal coverage of tissue. Hygiene requirements should take into consideration that some patients have limited hand dexterity and poor hygiene
The opinions and assertions contained herein are those of the authors and are not to be construed as official or as reflecting the view of the Department of the Army. Presented at the Fortieth Annual Meeting of the American Academy of Maxillofacial Prosthetics, Tampa, Fla. %olonel, DC, USA, Chief, Maxillofacial Prosthetics.
bColonel, DC, USA; Program Director, Oral and Maxillofacial Surgery Residency Program. 10/l/48233
OCTOBER
1993
motivation. Ideally, hygiene procedures can be enhanced when the motivation is reinforced by the patient’s spouse. The retentive element for an implant-retained facial prosthesis is designed so that the retentive bar is comfortable, conveniently hygienic, and designed without compromising the correct contours of the anatomic part being replaced. The purpose of this article is to suggest various retentive designs for facial prostheses that accomplish these requirements.
Auricular
prosthesis
The temporal bone has sufficient thickness to accept a 3 or 4 mm implant. With the use of a surgical guide made from the fabrication of a waxed prosthesis, the optimal position of the implants is determined. The abutments must exit the skin beneath the concha of the anticipated prosthesis so that the contours of the prosthetic ear are not compromised. A minimum of two implants are needed, positioned approximately 18 mm from the center of the external auditory meatus and 15 mm from each other. This design permits better support, stress distribution, and retention of the prosthesis. The abutments are jointed by a bar constructed in a C-shaped design to improve the stability and retention of the prosthesis (Fig. 1). The bar can be extended 10 to 15 mm beyond the abutments for better distribution of stability and retention. Three retentive clips (DCA 110, Nobelpharma U.S., Waltham, Mass.) or magnets (Shiner SR, Preat Corp., San Mateo, Calif.) and a bar do not appear to compromise the contours of the prosthesis. The presurgical waxed prosthesis will determine whether magnets or retentive clips should be used. An acrylic resin section is constructed within the prosthesis to house the retentive elements.
Nasal prosthesis For a nasal defect, the anterior surface of the maxilla just inferior to the nasal cavity offers sufficient. thickness of bone and an optimal position for 4 mm implants. Longer implants, 6 mm or greater, are possible in this area.6 It is recommended that a waxed pattern of the prosthesis be
329
THE
JOURNAL
OF PROSTHETlC
DENTISTRY
Fig. Fig.
AND
DONOVAN
1. Suggested retentive bar design for an auricular prosthesis. 2. Suggested retentive bar design for a nasal prosthesis.
completed before the placement of the implants so that the position of the abutments and the retentive elements do not compromise the contours of the prosthesis. A split-thickness skin graft is needed on the sides of the defect to provide a firm nonmovable foundation for the nasal prosthesis. This procedure will reduce the mobility of the tissue bed under the prosthesis and minimize the stress on the implants. The septal cartilage must be surgically reduced anteriorly. This procedure will provide room for the prosthesis to engage the lateral walls of the defect and increase the stability of the prosthesis. A minimum of two implants are required, positioned in each lateral rounded nasal eminence. Because the implants are not evenly distributed and are located in one part of the defect, the abutments are connected by a bar (Fig. 2). The bar can be extended superiorly 10 to 15 mm from the abutments for better distribution of retention for the prosthesis. An acrylic resin section is constructed with the pros-
330
GARY
thesis to house the retentive elements. Retentive clips or magnets can be used.
Orbital
prosthesis
For an orbital defect, the superior, lateral, and inferior orbital rims are possible sites for 3 or 4 mm implants. Ideally three or four implants are needed. The long axes of the implants should be directed toward the center of the orbit. If some implants are directed posteriorly toward the cranial fossa while other implants are directed anteriorly, the path of insertion may not accommodate a one-piece retentive bar. A presurgical waxed prosthesis should give the necessary information as to the ideal position of the implants so as not to interfere with the ocular portion of the prosthesis. Normally, the anterior position of the ocular prosthesis is 5 to 8 mm posterior to the supraorbital rim, 0 to 2 mm posterior to the infraorbital rim, and 8 to 12 mm anterior to the lateral orbital rim.7
VOLUME
70
NUMBER
4
GARY
AND
DONOVAN
THE
Fig. Fig.
1993
OF PROSTHETIC
DENTISTRY
3. Suggested retentive bar design for an orbital prosthesis. 4. Suggested retentive design using individual abutments for re,te!nti.on.
The type of retentive design is dictated by the position of the retentive bar and its relation to the ocular portion of the prosthesis. For large defects, it is best to connect the abutments with a bar (Fig. 3) because the implants are not evenly distributed. The retentive bar will contain the stainless steel keepers. An acrylic resin section houses the magnets and possibly a clip for this prosthesis. If the bar inhibits the ocular position of the orbital prosthesis, individual abutments can be used for retention (Fig. 4). The stainless steel keepers are positioned on the abutments and the magnets are part of the acrylic resin section of the prosthesis. The amount of retention is less because the magnets are directed laterally. It may be necessary to use the medial walls of the defect for additional retention and stability. Because of the uncomplicated design of the stainless steel keepers on the abutments, the patient is
OCTOBER
JOURNAL
provided better access to maintain hygiene around the abutments. SUMMARY Osseointegrated implants provide an alternative method of retention for facial prostheses. Use of OSseointegrated implants with magnets or clip retention should be considered for auricular, nasal, and orbital prostheses. REFERENCES 1. Tjellstrom A, Yontchev E, Lindstrom J, Branemark P-I. Five years’ experience with bone-anchored auricular prostheses. Otolaryngol Head Neck Surg 1985;93:366-72. 2. Holgers KM, Tjellstrom A, Bjursten LM, Erlandsson BE. Soft tissue reactions around percutaneous implants: a clinical study on skin-penetrating titanium implants used for bone-anchored auricular prostheses. Int J Oral Maxillofac Implants 1987;2:35-9.
331
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
6. Pare1 SM, Holt GR, Branemark P-I, Tjellstrom A. Osseointegration and facial prosthetics. Int J Oral Maxillofac Implants 1986;1:27-9. 4. ‘I’olman DE, Desjerdins RP. Extraoral application of osseointegrated implants. J Oral MaxilIofac Surg 1991;49:33-45. 5. TjeUstrom A, Rosenhall U, Lindstrom J, Hallen 0, Albrektsson T, Branemark P-I. Five year experience with skin-penetrating boneanchored implants in the temporal bone. Acta Otolaryngol1983;95:568-
75. 6. Jensen OT, Brownd C, Blacker J. Nasofacial osseointegrated
implants.
prostheses supported by Int J Oral Maxillofac Implants 1992;7:203- 11.
GARY
AND
DONOVAN
7. Epker BN, Stella JP. Reconstruction of frontal and frontal-nasal deformities with prefabricated custom implants. J Oral Maxillofac Surg 1989:47:1272-6.
Reprint
requests to:
DR. JOHNJ.GARY JOHN L.MCCLELLAN MEMORIALVETERANS ~~OOW~TSEVENTHSTREET LITTLE ROCK,AR 72205
HOSPITAL
VOLUME70
NUMBER4
designs DDS,a
Beaumont
for bone-anchored
and M. Donovan,
Army Medical
facial
prostheses
DDSb
Center, Fort Bliss, Tex.
A facial prosthesis can be retained by bone-anchored implants and by a retentive bar. Because tissue response is critical around the abutments, the retentive bar should be constructed so that it is comfortable, conveniently hygienic, and designed without compromising the contours of the prosthesis. (J PROSTHET DENT 1993;70:329-32.)
A.
facial prosthesis can be a possible solution for the patient with a facial defect that may not be corrected by surgical reconstruction. A prosthesis can be designed that fulfills the esthetic needs of the patient, but prosthesis retention may not be optimal. Skin adhesives can be used to retain the prosthesis but problems of retention, margin integrity, skin irritations, and prosthesis misalignment can still exist. The use of bone-anchored implants to retain a facial prosthesis can minimize retention problems’-* and provide a psychologically acceptable prosthesis. With the use of bone-anchored implants, optimal tissue health around the abutments is a primary concern. The reaction of the skin around skin-penetrating abutments can be graded according to the standards presented by Holgers et aL2 Optimal tissue health can be obtained by surgical modification of the tissue around abutments, adequate distance between the implants, good hygiene, and hygienic contours of the retentive bar. Minimal movement of the tissues around the abutments is accomplished by removal of the subcutaneous tissue approximately 10 mm around the implants during the second surgical stage. A skin graft may be needed to establish a zone free from hair at least 7 mm around the abutments.2T 5 Implants must be placed with sufficient distance from each other to permit hygiene of the skin around the abutments. Because tissue response is critical around the abutments, hygiene procedures should be facilitated by designing the retentive bar with minimal coverage of tissue. Hygiene requirements should take into consideration that some patients have limited hand dexterity and poor hygiene
The opinions and assertions contained herein are those of the authors and are not to be construed as official or as reflecting the view of the Department of the Army. Presented at the Fortieth Annual Meeting of the American Academy of Maxillofacial Prosthetics, Tampa, Fla. %olonel, DC, USA, Chief, Maxillofacial Prosthetics.
bColonel, DC, USA; Program Director, Oral and Maxillofacial Surgery Residency Program. 10/l/48233
OCTOBER
1993
motivation. Ideally, hygiene procedures can be enhanced when the motivation is reinforced by the patient’s spouse. The retentive element for an implant-retained facial prosthesis is designed so that the retentive bar is comfortable, conveniently hygienic, and designed without compromising the correct contours of the anatomic part being replaced. The purpose of this article is to suggest various retentive designs for facial prostheses that accomplish these requirements.
Auricular
prosthesis
The temporal bone has sufficient thickness to accept a 3 or 4 mm implant. With the use of a surgical guide made from the fabrication of a waxed prosthesis, the optimal position of the implants is determined. The abutments must exit the skin beneath the concha of the anticipated prosthesis so that the contours of the prosthetic ear are not compromised. A minimum of two implants are needed, positioned approximately 18 mm from the center of the external auditory meatus and 15 mm from each other. This design permits better support, stress distribution, and retention of the prosthesis. The abutments are jointed by a bar constructed in a C-shaped design to improve the stability and retention of the prosthesis (Fig. 1). The bar can be extended 10 to 15 mm beyond the abutments for better distribution of stability and retention. Three retentive clips (DCA 110, Nobelpharma U.S., Waltham, Mass.) or magnets (Shiner SR, Preat Corp., San Mateo, Calif.) and a bar do not appear to compromise the contours of the prosthesis. The presurgical waxed prosthesis will determine whether magnets or retentive clips should be used. An acrylic resin section is constructed within the prosthesis to house the retentive elements.
Nasal prosthesis For a nasal defect, the anterior surface of the maxilla just inferior to the nasal cavity offers sufficient. thickness of bone and an optimal position for 4 mm implants. Longer implants, 6 mm or greater, are possible in this area.6 It is recommended that a waxed pattern of the prosthesis be
329
THE
JOURNAL
OF PROSTHETlC
DENTISTRY
Fig. Fig.
AND
DONOVAN
1. Suggested retentive bar design for an auricular prosthesis. 2. Suggested retentive bar design for a nasal prosthesis.
completed before the placement of the implants so that the position of the abutments and the retentive elements do not compromise the contours of the prosthesis. A split-thickness skin graft is needed on the sides of the defect to provide a firm nonmovable foundation for the nasal prosthesis. This procedure will reduce the mobility of the tissue bed under the prosthesis and minimize the stress on the implants. The septal cartilage must be surgically reduced anteriorly. This procedure will provide room for the prosthesis to engage the lateral walls of the defect and increase the stability of the prosthesis. A minimum of two implants are required, positioned in each lateral rounded nasal eminence. Because the implants are not evenly distributed and are located in one part of the defect, the abutments are connected by a bar (Fig. 2). The bar can be extended superiorly 10 to 15 mm from the abutments for better distribution of retention for the prosthesis. An acrylic resin section is constructed with the pros-
330
GARY
thesis to house the retentive elements. Retentive clips or magnets can be used.
Orbital
prosthesis
For an orbital defect, the superior, lateral, and inferior orbital rims are possible sites for 3 or 4 mm implants. Ideally three or four implants are needed. The long axes of the implants should be directed toward the center of the orbit. If some implants are directed posteriorly toward the cranial fossa while other implants are directed anteriorly, the path of insertion may not accommodate a one-piece retentive bar. A presurgical waxed prosthesis should give the necessary information as to the ideal position of the implants so as not to interfere with the ocular portion of the prosthesis. Normally, the anterior position of the ocular prosthesis is 5 to 8 mm posterior to the supraorbital rim, 0 to 2 mm posterior to the infraorbital rim, and 8 to 12 mm anterior to the lateral orbital rim.7
VOLUME
70
NUMBER
4
GARY
AND
DONOVAN
THE
Fig. Fig.
1993
OF PROSTHETIC
DENTISTRY
3. Suggested retentive bar design for an orbital prosthesis. 4. Suggested retentive design using individual abutments for re,te!nti.on.
The type of retentive design is dictated by the position of the retentive bar and its relation to the ocular portion of the prosthesis. For large defects, it is best to connect the abutments with a bar (Fig. 3) because the implants are not evenly distributed. The retentive bar will contain the stainless steel keepers. An acrylic resin section houses the magnets and possibly a clip for this prosthesis. If the bar inhibits the ocular position of the orbital prosthesis, individual abutments can be used for retention (Fig. 4). The stainless steel keepers are positioned on the abutments and the magnets are part of the acrylic resin section of the prosthesis. The amount of retention is less because the magnets are directed laterally. It may be necessary to use the medial walls of the defect for additional retention and stability. Because of the uncomplicated design of the stainless steel keepers on the abutments, the patient is
OCTOBER
JOURNAL
provided better access to maintain hygiene around the abutments. SUMMARY Osseointegrated implants provide an alternative method of retention for facial prostheses. Use of OSseointegrated implants with magnets or clip retention should be considered for auricular, nasal, and orbital prostheses. REFERENCES 1. Tjellstrom A, Yontchev E, Lindstrom J, Branemark P-I. Five years’ experience with bone-anchored auricular prostheses. Otolaryngol Head Neck Surg 1985;93:366-72. 2. Holgers KM, Tjellstrom A, Bjursten LM, Erlandsson BE. Soft tissue reactions around percutaneous implants: a clinical study on skin-penetrating titanium implants used for bone-anchored auricular prostheses. Int J Oral Maxillofac Implants 1987;2:35-9.
331
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
6. Pare1 SM, Holt GR, Branemark P-I, Tjellstrom A. Osseointegration and facial prosthetics. Int J Oral Maxillofac Implants 1986;1:27-9. 4. ‘I’olman DE, Desjerdins RP. Extraoral application of osseointegrated implants. J Oral MaxilIofac Surg 1991;49:33-45. 5. TjeUstrom A, Rosenhall U, Lindstrom J, Hallen 0, Albrektsson T, Branemark P-I. Five year experience with skin-penetrating boneanchored implants in the temporal bone. Acta Otolaryngol1983;95:568-
75. 6. Jensen OT, Brownd C, Blacker J. Nasofacial osseointegrated
implants.
prostheses supported by Int J Oral Maxillofac Implants 1992;7:203- 11.
GARY
AND
DONOVAN
7. Epker BN, Stella JP. Reconstruction of frontal and frontal-nasal deformities with prefabricated custom implants. J Oral Maxillofac Surg 1989:47:1272-6.
Reprint
requests to:
DR. JOHNJ.GARY JOHN L.MCCLELLAN MEMORIALVETERANS ~~OOW~TSEVENTHSTREET LITTLE ROCK,AR 72205
HOSPITAL
VOLUME70
NUMBER4