EVULSION
OF PERCUTANEOUS
Fig. 7. Completed posite prosthesis.
silicone
IMPLANT
ABUTMENT
elastomer-acrylic
resin com-
surrounding bone revealed the implant fixture and tissues to be intact. A new abutment was connected and physical stability testing proved positive. It was of interest to note that in the immediate and ensuing posttraumatic period the patient experienced no pain. or discomfort. A bar system (Fig. 6) was constructed on the three abutments to retain a silicone prosthesis (Cosmesil, Cosmedica, Cardiff, Wales, U.K.) bonded to an acrylic resin substructure with four Ackermann M-D clips (Swiss NF Metals, Ontario, Canada) (Fig. 7). The completed prosthesis (Fig. 8) has been in function for 16 months and the patient remains symptom-free. The traumatic incident reported, in the absence of scientific data, provides anecdotal information on the poten-
Apparent intrusion implant-supported
of natural prosthesis:
Fig.
8. Lateral
view of completed
prosthesis.
tial of craniofacial implants to withstand physical insult. The uncontrolled nature of the insult reported provides no opportunity for extrapolation to possible responses under other conditions. The implant appears to have survived in the short term but follow-up will be needed to determine the long-term consequences to the integrity of the osseointegrated interface. Reprint
requests
to:
DR. J. F. WOLFAARDT FACULTY OF DENTISTRY-UNIVERSITY 4036 DENTISTRY/PHARMACY BLDG. EDMONTON, ALTA., CAI\ADA T6G 2N8
OF ALBERTA
teeth under an A clinical report
George C. Cho, DDS,a and Winston W. L. Chee, BDSb University of Southern California, School of Dentistry, Los Angeles, Calif.,
I3
estoring arches with natural teeth and implants may require connecting them together to optimize support and stability. This clinical report describes the use on natural teeth of telescopic copings that are attached to implant abutments. For this treatment the units were not cemented, to allow for removal of the prostheses.
aAssistant Professor, Department of Restorative Dentistry. bAssistant Professor, Director of Implant Dentistry. 10/l/36694 THE
JOURNAL
OF PROSTHETIC
DENTISTRY
The patient required full-arch restorations in the maxillary and mandibular arches. The only sound teeth remaining were the maxillary canines, laterals, and left central incisor, and the mandibular left first premolar, the right canine, and the right second premolar. The patient had a severe gag reflex, which precluded treatment with removable prostheses. The maxillary arch was restored with a six-unit anterior restoration with tooth 8 as a pontic and an implant-supported fixed partial denture for each of the posterior quadrants. The mandibular arch was restored after placement of six 3
CHQ
Fig. 1. Distribution ments in mandibular
of natural arch.
teeth and implant
AND
CHEE
abut-
Fig. 3. Periapical radiograph shows complete seating of implant superstructure and natural abutment copings.
Fig. 2. Qcclusal tion.
view of completed
mandibular
restora-
implants (Branemark, Nobelpharma, Chicago, Ill.) with the following distribution: two implants in the left posterior arch distal to the first premolar; two implants in the anterior arch, and two implants in the right posterior arch placed alternately with the two remaining natural teeth the right canine and second premolar. The remaining natural teeth were restored with gold copings to telescope with the implant superstructure (Fig. 1). The mandibular fixed restoration was designed with a two-unit splinted implant restoration on the posterior left arch supported by two implants with a semiprecision slottype attachment on the mesial end of the restoration. A seven-unit fixed partial denture in the anterior region was supported by two implants and by the mandibular left first premolar and the right canine, which were restored with telescopic copings with keyway portions of attachments on the most distal units of the superstructure. A three-unit fixed partial denture was supported by two implants alternately placed between tooth 29, which was restored with a telescopic coping with a key portion of an attachment on the mesial unit of the superstructure (Fig. 2). 4
Fig. 4. Superstructure 2-week follow-up.
is well
adapted
to copings
at
There is a differential resiliency between an implant and a natural tooth because of the osseointegration of the implants and the lack of peri-implant soft tissue attachment.1,2 Assuming that the framework is rigid, the load to the prostheses will be borne by the implants alone in normal function. If one of the terminal abutments is a natural tooth, then loading of that tooth can potentially occur. The restorations were telescoped over the gold copings passively and were left uncemented to facilitate removal of the restoration. Seating of the superstructure to the implants and the gold copings were JULY
1992
VOLUME
68
NUMBER
1
APPARENT
TOOTH
INTRUSION
Fig. 5. Marginal discrepancy of implant and copings at S-month follow-up.
superstructure
verified clinically and with periapical radiographs (Figs. 3 and 4).“,’ The patient was followed up monthly to evaluate oral hygiene and any maintenance needed for the prostheses. On the fifth month of follow-up a discrepancy between the margin of the gold coping and the superstructure on the right canine and second premolar was detected (Fig. 5). Periapical radiographs were taken to verify the complete seating of the restoration on the implants. The marginal discrepancy between coping and superstructure was also evident (Fig. 6). The left first premolar was similarly examined and indicated no apparent intrusion at the time. The left first premolar was believed to be the only tooth to have the potential to be loaded because it was a terminal abutment of the anterior splint and may be considered a cantilever. The loading in this situation may be a benefit by providing stimulation of the periodontal ligament of this natural tooth. Loading of the tooth may have occurred through flexion of the abutment screw even if the framework is rigid.6 The cause of the discrepancy is unknown. The teeth must have intruded, or the implants extruded. No plausible explanation has been found for either to occur. Because occlusion with the maxillary arch is intact, it is likely that the discrepancy is caused by the intrusion of the natural teeth. Other observations of migrations of natural abutment teeth have been reported, but the teeth were usually terminal abutments in a fixed partial denture. When fixed restorations are planned with mixed abutments, the problem of differential loading and mobility of the abutments must be addressed for long-term success. In this situation the benefit of retaining any natural teeth is questionable. The treatment of the patient is removal of the restoration and replacement with a cementing medium, which also acts as a filler. The junctions are all supragingival and can be finished flush. If the intrusion continues,
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Fig. 6. Marginal discrepancy of implant superstructure to copings is evident radiographically. Complete seating of implant abutments to fixtures is also verified. the natural teeth in question can be extracted without consequence to the integrity of the restoration. In conclusion and in retrospect, a more aggressive approach could have yielded a more predictable situation in this particular treatment plan. The natural teeth could have been extracted after the second-stage implant surgery confirmed the successful integration of all the fixtures, or even after loading the implants with a provisional restoration.
REFERENCES 1. Muhleman HR, Zander HA. Tooth mobility. III. The mechanism of tooth mobility. J Periodontol 1954;25:128-37. 2. Glantz PO, Nyman S, Strandman E, Rankow K. On functional strain in fixed mandibular reconstructions. II. An in viva study. Acta Odontol Stand 1984;42:269-76. 3. Ericsson I, Lekholm U, Branemark PI, Lindhe J, Glantz PO, Nyman S. A clinical evaluation of fixed-bridge restorations supported by the combination of teeth and osseointegrated titanium implants. J Clin Periodonto1 1986;13:307-12. 4. Lekholm U. Clinical procedures for treatment with osseointegrated dental implants. J PROSTHET DENT 1983;50:116-20. 5. Adell R, Lekholm U, Rockler B, Branemark PI. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg 1981;6:387-416. 6. McGlumphy EA, Campagni WV, Peterson LJ. A comparison of the stress transfer characteristics of a dental implant with a rigid or a resilient internal element. J PROSTHET DENT 1989;62:586-93. Reprint requests to: GEORGE C. CEO, DDS SCHOOL OF DENTISTRY, ROOM 4381 UNIVERSITY OF SOUTHERN CALIFORNIA UNIVERSITY PARK Los ANGELES, CA 90089-0641
OF PERCUTANEOUS
Fig. 7. Completed posite prosthesis.
silicone
IMPLANT
ABUTMENT
elastomer-acrylic
resin com-
surrounding bone revealed the implant fixture and tissues to be intact. A new abutment was connected and physical stability testing proved positive. It was of interest to note that in the immediate and ensuing posttraumatic period the patient experienced no pain. or discomfort. A bar system (Fig. 6) was constructed on the three abutments to retain a silicone prosthesis (Cosmesil, Cosmedica, Cardiff, Wales, U.K.) bonded to an acrylic resin substructure with four Ackermann M-D clips (Swiss NF Metals, Ontario, Canada) (Fig. 7). The completed prosthesis (Fig. 8) has been in function for 16 months and the patient remains symptom-free. The traumatic incident reported, in the absence of scientific data, provides anecdotal information on the poten-
Apparent intrusion implant-supported
of natural prosthesis:
Fig.
8. Lateral
view of completed
prosthesis.
tial of craniofacial implants to withstand physical insult. The uncontrolled nature of the insult reported provides no opportunity for extrapolation to possible responses under other conditions. The implant appears to have survived in the short term but follow-up will be needed to determine the long-term consequences to the integrity of the osseointegrated interface. Reprint
requests
to:
DR. J. F. WOLFAARDT FACULTY OF DENTISTRY-UNIVERSITY 4036 DENTISTRY/PHARMACY BLDG. EDMONTON, ALTA., CAI\ADA T6G 2N8
OF ALBERTA
teeth under an A clinical report
George C. Cho, DDS,a and Winston W. L. Chee, BDSb University of Southern California, School of Dentistry, Los Angeles, Calif.,
I3
estoring arches with natural teeth and implants may require connecting them together to optimize support and stability. This clinical report describes the use on natural teeth of telescopic copings that are attached to implant abutments. For this treatment the units were not cemented, to allow for removal of the prostheses.
aAssistant Professor, Department of Restorative Dentistry. bAssistant Professor, Director of Implant Dentistry. 10/l/36694 THE
JOURNAL
OF PROSTHETIC
DENTISTRY
The patient required full-arch restorations in the maxillary and mandibular arches. The only sound teeth remaining were the maxillary canines, laterals, and left central incisor, and the mandibular left first premolar, the right canine, and the right second premolar. The patient had a severe gag reflex, which precluded treatment with removable prostheses. The maxillary arch was restored with a six-unit anterior restoration with tooth 8 as a pontic and an implant-supported fixed partial denture for each of the posterior quadrants. The mandibular arch was restored after placement of six 3
CHQ
Fig. 1. Distribution ments in mandibular
of natural arch.
teeth and implant
AND
CHEE
abut-
Fig. 3. Periapical radiograph shows complete seating of implant superstructure and natural abutment copings.
Fig. 2. Qcclusal tion.
view of completed
mandibular
restora-
implants (Branemark, Nobelpharma, Chicago, Ill.) with the following distribution: two implants in the left posterior arch distal to the first premolar; two implants in the anterior arch, and two implants in the right posterior arch placed alternately with the two remaining natural teeth the right canine and second premolar. The remaining natural teeth were restored with gold copings to telescope with the implant superstructure (Fig. 1). The mandibular fixed restoration was designed with a two-unit splinted implant restoration on the posterior left arch supported by two implants with a semiprecision slottype attachment on the mesial end of the restoration. A seven-unit fixed partial denture in the anterior region was supported by two implants and by the mandibular left first premolar and the right canine, which were restored with telescopic copings with keyway portions of attachments on the most distal units of the superstructure. A three-unit fixed partial denture was supported by two implants alternately placed between tooth 29, which was restored with a telescopic coping with a key portion of an attachment on the mesial unit of the superstructure (Fig. 2). 4
Fig. 4. Superstructure 2-week follow-up.
is well
adapted
to copings
at
There is a differential resiliency between an implant and a natural tooth because of the osseointegration of the implants and the lack of peri-implant soft tissue attachment.1,2 Assuming that the framework is rigid, the load to the prostheses will be borne by the implants alone in normal function. If one of the terminal abutments is a natural tooth, then loading of that tooth can potentially occur. The restorations were telescoped over the gold copings passively and were left uncemented to facilitate removal of the restoration. Seating of the superstructure to the implants and the gold copings were JULY
1992
VOLUME
68
NUMBER
1
APPARENT
TOOTH
INTRUSION
Fig. 5. Marginal discrepancy of implant and copings at S-month follow-up.
superstructure
verified clinically and with periapical radiographs (Figs. 3 and 4).“,’ The patient was followed up monthly to evaluate oral hygiene and any maintenance needed for the prostheses. On the fifth month of follow-up a discrepancy between the margin of the gold coping and the superstructure on the right canine and second premolar was detected (Fig. 5). Periapical radiographs were taken to verify the complete seating of the restoration on the implants. The marginal discrepancy between coping and superstructure was also evident (Fig. 6). The left first premolar was similarly examined and indicated no apparent intrusion at the time. The left first premolar was believed to be the only tooth to have the potential to be loaded because it was a terminal abutment of the anterior splint and may be considered a cantilever. The loading in this situation may be a benefit by providing stimulation of the periodontal ligament of this natural tooth. Loading of the tooth may have occurred through flexion of the abutment screw even if the framework is rigid.6 The cause of the discrepancy is unknown. The teeth must have intruded, or the implants extruded. No plausible explanation has been found for either to occur. Because occlusion with the maxillary arch is intact, it is likely that the discrepancy is caused by the intrusion of the natural teeth. Other observations of migrations of natural abutment teeth have been reported, but the teeth were usually terminal abutments in a fixed partial denture. When fixed restorations are planned with mixed abutments, the problem of differential loading and mobility of the abutments must be addressed for long-term success. In this situation the benefit of retaining any natural teeth is questionable. The treatment of the patient is removal of the restoration and replacement with a cementing medium, which also acts as a filler. The junctions are all supragingival and can be finished flush. If the intrusion continues,
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Fig. 6. Marginal discrepancy of implant superstructure to copings is evident radiographically. Complete seating of implant abutments to fixtures is also verified. the natural teeth in question can be extracted without consequence to the integrity of the restoration. In conclusion and in retrospect, a more aggressive approach could have yielded a more predictable situation in this particular treatment plan. The natural teeth could have been extracted after the second-stage implant surgery confirmed the successful integration of all the fixtures, or even after loading the implants with a provisional restoration.
REFERENCES 1. Muhleman HR, Zander HA. Tooth mobility. III. The mechanism of tooth mobility. J Periodontol 1954;25:128-37. 2. Glantz PO, Nyman S, Strandman E, Rankow K. On functional strain in fixed mandibular reconstructions. II. An in viva study. Acta Odontol Stand 1984;42:269-76. 3. Ericsson I, Lekholm U, Branemark PI, Lindhe J, Glantz PO, Nyman S. A clinical evaluation of fixed-bridge restorations supported by the combination of teeth and osseointegrated titanium implants. J Clin Periodonto1 1986;13:307-12. 4. Lekholm U. Clinical procedures for treatment with osseointegrated dental implants. J PROSTHET DENT 1983;50:116-20. 5. Adell R, Lekholm U, Rockler B, Branemark PI. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg 1981;6:387-416. 6. McGlumphy EA, Campagni WV, Peterson LJ. A comparison of the stress transfer characteristics of a dental implant with a rigid or a resilient internal element. J PROSTHET DENT 1989;62:586-93. Reprint requests to: GEORGE C. CEO, DDS SCHOOL OF DENTISTRY, ROOM 4381 UNIVERSITY OF SOUTHERN CALIFORNIA UNIVERSITY PARK Los ANGELES, CA 90089-0641
