SECTIONEDITORS
A surgical Philip
guide
J. Render,
DMD,*
for implant and Jeffery
United States Army Area Dental Laboratory,
placement
T. Fondak,
DDSb
Fort Sam Houston, Tex.
Mounted diagnostic casts aid in determining whether sufficient space exists for a fixed cantilevered implant prosthesis. These casts are also used to construct a surgical guide. Such a technique is described. (J PROSTHET DENT 1992;67:831-2.)
Predictable
results with an osseointegrated prosthesis depend on coordination between the prosthodontist and the surgeon. The coordinator of the effort should be the prosthodontists since prosthesis fabrication, maintenance, and patient recall are their responsibility.’ Fixture spacing, alignment of fixtures, and interarch space are the three cosmetic and mechanical considerations that Branemark et a1.2consider critical to the success of a prosthesis. When using the fixed cantilever prosthesis for the mandible, approximately 10 to 12 mm is desirable from the crest of the edentulous ridge to the maxillary incisal edge to allow space for a rigid prosthesis and accessfor hygiene. Discerning whether this space is available is difficult without
The opinions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the United States Army or the Department of Defense. %olonel, U.S. Army, Dental Corps; Commander, U.S. Army Area Dental Laboratory, Fort Sam Houston, Tex. bLieutenant Colonel, U.S. Army, Dental Corps; Clinical Prosthodontist, U.S. Army Dental Activity, Fort Hood, Tex. 10/l/35599
Fig. 1. Final cast before mounting and separation of master impression and occlusal record. THE
JOURNAL
OF PROSTHE’TIC
DENTISTRY
mounted casts. A surgical stent to guide the surgeon to optimal fixture placement is also beneficial. The procedure to be described produces mounted diagnostic casts for space measurement and surgical stent fabrication. TECHNIQUE Clinical
phase
1. Make alginate (irreversible hydrocolloid) impressions of the cameo surface of the maxillary denture and of the internal surface of the mandibular denture. 2. Pour a maxillary cast in stone and make a mandibular impression tray by the “salt and pepper” technique directly on the alginate. Add a wax rim to the impression tray.3 With use of modeling plastic (Kerr, Romulus, Mich.), border-mold the impression tray to achieve maximum posterior extension. This extension will add stability to the surgical stent since no surgical flap is made in that area. 3. Make a final impression with a polyether material (Impregum, Premier-Espe, Norristown, Pa.). 4. Make jaw relationship records with use of the impression base rather than the existing mandibular denture. 5. Pour the final cast in stone and rough-trim it, but do not separate from the final impression.
Fig. 2. Measurement confirms sufficient cantilevered implant prosthesis.
space for fixed 831
RENDER
AND
FONDAK
3. Note position of resin bar, guide pin, space beneath stent anteriorly, and space for surgical flap. A, Lateral view; B, occlusal view.
Fig.
10. For a right-handed surgeon, place a straight handpiece bur perpendicular to the bar in the area of the left lateral incisor to serve as a two-dimensional parallelism guide. Surgical
4. Note angulation and parallelism of implants after abutment connection.
Fig.
6. After mounting the casts, separate the impression and trim the casts (Fig. 1). 7. Measure the available space for the prosthesis on the mounted casts (Fig. 2). Laboratory
phase
8. From metal foramen to mental foramen on the master cast, wax up and process an acrylic bar approximately 4 mm square so that its labial surface estimates the labial surface of the final restoration.4 The objective is to prevent screw-access holes from passing through the labial surface of the final restoration. 9. Relieve the resin bar on the tissue surface to allow space for the surgical flap (Fig. 3). The stent is supported posteriorly where no flap is raised and is, therefore, overextended for maximum stability. The small acrylic resin bar design was chosen since bars replicating the proposed mandibular dentition often interfere with the surgical handpiece.
phase
11. After the surgical flap is raised, place the gas-sterilized stent in position and stabilize it with firm posterior pressure. Evaluate the quality of the bone lingual to the stent bar and mark the implant sites with a round bur. 12. Prepare the site near the midline with use of the complete sequence of drills while maintaining parallelism with the guide on the stent. 13. Upon completion of this site, remove the stent and place a Branemark direction indicator (Nobelpharma USA Inc, Chicago, Ill.) in the completed site. The remaining sites are prepared maintaining parallelism to the direction indicator (Fig. 4). SUMMARY Diagnostic casts mounted in the correct vertical and horizontal relations are essential for evaluation of space to accommodate osseointegrated implants. With use of the technique described, these casts can also be used to fabricate a surgical stent. REFERENCES 1. Barn&t BG, Krump JL. Implant dentistry: the significance of a team appr0ach.J PROSTHET DENT 1987;58:69-73. 2. Branemark PI, Zarh GA, Albrektsson T. Tissue-integrated prostheses osseointegration in clinical dentistry. Chicago: Quintessence, 1995. 3. Render PJ. Fabrication of custom trays from existing dentures. J
PROSTHETDENT~~~~;~~%~~-~. 4. Balshi TJ, Garver J Oral Maxillofac
DG. Surgical guidestents Surg 1987;45:463-5.
for placement
of implants.
VOLUME
NUMBER
Reprint requests to: DR. PHILIP J. RENDER U.S.ARMYAREADENTALLABORATORY FT.SAM HOUSTON,TX 78234-6200
JUNE
1992
67
6
A surgical Philip
guide
J. Render,
DMD,*
for implant and Jeffery
United States Army Area Dental Laboratory,
placement
T. Fondak,
DDSb
Fort Sam Houston, Tex.
Mounted diagnostic casts aid in determining whether sufficient space exists for a fixed cantilevered implant prosthesis. These casts are also used to construct a surgical guide. Such a technique is described. (J PROSTHET DENT 1992;67:831-2.)
Predictable
results with an osseointegrated prosthesis depend on coordination between the prosthodontist and the surgeon. The coordinator of the effort should be the prosthodontists since prosthesis fabrication, maintenance, and patient recall are their responsibility.’ Fixture spacing, alignment of fixtures, and interarch space are the three cosmetic and mechanical considerations that Branemark et a1.2consider critical to the success of a prosthesis. When using the fixed cantilever prosthesis for the mandible, approximately 10 to 12 mm is desirable from the crest of the edentulous ridge to the maxillary incisal edge to allow space for a rigid prosthesis and accessfor hygiene. Discerning whether this space is available is difficult without
The opinions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the United States Army or the Department of Defense. %olonel, U.S. Army, Dental Corps; Commander, U.S. Army Area Dental Laboratory, Fort Sam Houston, Tex. bLieutenant Colonel, U.S. Army, Dental Corps; Clinical Prosthodontist, U.S. Army Dental Activity, Fort Hood, Tex. 10/l/35599
Fig. 1. Final cast before mounting and separation of master impression and occlusal record. THE
JOURNAL
OF PROSTHE’TIC
DENTISTRY
mounted casts. A surgical stent to guide the surgeon to optimal fixture placement is also beneficial. The procedure to be described produces mounted diagnostic casts for space measurement and surgical stent fabrication. TECHNIQUE Clinical
phase
1. Make alginate (irreversible hydrocolloid) impressions of the cameo surface of the maxillary denture and of the internal surface of the mandibular denture. 2. Pour a maxillary cast in stone and make a mandibular impression tray by the “salt and pepper” technique directly on the alginate. Add a wax rim to the impression tray.3 With use of modeling plastic (Kerr, Romulus, Mich.), border-mold the impression tray to achieve maximum posterior extension. This extension will add stability to the surgical stent since no surgical flap is made in that area. 3. Make a final impression with a polyether material (Impregum, Premier-Espe, Norristown, Pa.). 4. Make jaw relationship records with use of the impression base rather than the existing mandibular denture. 5. Pour the final cast in stone and rough-trim it, but do not separate from the final impression.
Fig. 2. Measurement confirms sufficient cantilevered implant prosthesis.
space for fixed 831
RENDER
AND
FONDAK
3. Note position of resin bar, guide pin, space beneath stent anteriorly, and space for surgical flap. A, Lateral view; B, occlusal view.
Fig.
10. For a right-handed surgeon, place a straight handpiece bur perpendicular to the bar in the area of the left lateral incisor to serve as a two-dimensional parallelism guide. Surgical
4. Note angulation and parallelism of implants after abutment connection.
Fig.
6. After mounting the casts, separate the impression and trim the casts (Fig. 1). 7. Measure the available space for the prosthesis on the mounted casts (Fig. 2). Laboratory
phase
8. From metal foramen to mental foramen on the master cast, wax up and process an acrylic bar approximately 4 mm square so that its labial surface estimates the labial surface of the final restoration.4 The objective is to prevent screw-access holes from passing through the labial surface of the final restoration. 9. Relieve the resin bar on the tissue surface to allow space for the surgical flap (Fig. 3). The stent is supported posteriorly where no flap is raised and is, therefore, overextended for maximum stability. The small acrylic resin bar design was chosen since bars replicating the proposed mandibular dentition often interfere with the surgical handpiece.
phase
11. After the surgical flap is raised, place the gas-sterilized stent in position and stabilize it with firm posterior pressure. Evaluate the quality of the bone lingual to the stent bar and mark the implant sites with a round bur. 12. Prepare the site near the midline with use of the complete sequence of drills while maintaining parallelism with the guide on the stent. 13. Upon completion of this site, remove the stent and place a Branemark direction indicator (Nobelpharma USA Inc, Chicago, Ill.) in the completed site. The remaining sites are prepared maintaining parallelism to the direction indicator (Fig. 4). SUMMARY Diagnostic casts mounted in the correct vertical and horizontal relations are essential for evaluation of space to accommodate osseointegrated implants. With use of the technique described, these casts can also be used to fabricate a surgical stent. REFERENCES 1. Barn&t BG, Krump JL. Implant dentistry: the significance of a team appr0ach.J PROSTHET DENT 1987;58:69-73. 2. Branemark PI, Zarh GA, Albrektsson T. Tissue-integrated prostheses osseointegration in clinical dentistry. Chicago: Quintessence, 1995. 3. Render PJ. Fabrication of custom trays from existing dentures. J
PROSTHETDENT~~~~;~~%~~-~. 4. Balshi TJ, Garver J Oral Maxillofac
DG. Surgical guidestents Surg 1987;45:463-5.
for placement
of implants.
VOLUME
NUMBER
Reprint requests to: DR. PHILIP J. RENDER U.S.ARMYAREADENTALLABORATORY FT.SAM HOUSTON,TX 78234-6200
JUNE
1992
67
6
