Case report
A female patient in a good general health consulted the prosthetic
department for a prosthetic rehabilitation with esthetic and functional
request.
The oral examination revealed cracks at the anterior incisors the 11 and
the 21, an inversion of the Spee’s curve and an abrasion on the
mandibular teeth. There were mandibular bridges from the 12 to the 16
and from the 33 to the 37. There were also maxillary bridge from the 24
to the 26. These fixed prostheses had a bad dento-prosthetic joint
(Figure 1 A,B,C).
The vertical dimension of occlusion was maintained.
The radiological examination showed that the 37 presented a bone lysis
reaching the apical third. An infrabony perforation was noted at the
level of the 33. The 15 was dilapidated. The other remaining teeth had a
radiological crown -radiological root ratio less than 1 except the 24
which presented an infra-osseous decay (Figure 1D).
Oral cavity sanitation treatments have been carried out including
hygiene motivation, removal of defective bridges, extraction of the 24,
37 and 33 and caries curettage on the 16. The 15 was reconstructed using
a false stump coping.
After the oral cavity sanitation phase, the patient was categorized
clinically as a Kennedy class III in the maxillary arch. In the
mandibular arch, the situation was more delicate in the presence of a
distal extension edentulism bordered anteriorly by the lateral incisor.
Based on the clinical data and the diagnosis elements, ceramo metallic
full arch was indicated in the maxilla.
In the mandibular arch, three treatment options were discussed with the
patient: implant supported fixed prosthesis (ISFP), ISRPD or
conventional RPD.
The patient was aware of the cost of an ISFP. Nevertheless, she wants a
stable and functional prosthesis. The decision was to realize an ISRPD
combined with fixed restorations on the anterior teeth. Locator
attachment will be used as a complementary retention device.
Study casts prepared from preliminary impressions were mounted on the
articulator at adequate occlusal vertical dimension. The prosthetic
usable occlusal height was equal to 6 millimeters (mm). The diagnostic
waxes and the director mounting realized constituted an indispensable
communication tool in the patient-practitioner-prosthetist triad (Figure
2). The conception of the prospective metal framework supported by
strategic implant has been elaborated (Figure 3).
Prosthetic steps were started with peripheral preparations of the 11,
21, 22, 23, 31, 32, 41, 42, 43 and the rectification of the preparations
on the 12, 15, 16 and 26 (figure 4 A,B) followed by the realization of
the first generation temporary fixed prostheses. The director mounting
was polymerized and served as mandibular provisional acrylic resin RPD.
This one was duplicated in order to be used as radiographic and surgical
guide.
The global impressions had been taken (figure 4 C,D), followed by the
occlusion recording. the fixed restorations were realized according to
the prospective layout of the metal framework (figure 4E). The
particularity of the mandibular crowns was the millings (figure 4 F)
that will receive the metal framework components.
Computed tomography assessment revealed bone deficiency in height in the
left mandibular posterior region (Figure 5). An implant will be placed
in the site of the left first molar to transform the terminal tooth loss
into an intercalary edentulism. The length and the diameter of this
implant were respectively 8.5 mm and 4.2 mm.
Implant placement has been performed (Figure 6A to F). Following
osseointegration of the implant, healing abutment was placed and was
left for 2 weeks to allow the healing of peri-implant soft tissues
(Figure 6G).
The realization of ISRPD was started by making the primary anatomical
impression using a commercial impression tray and a silicone according
to the simultaneous double mixing technique. The healing screw was in
place to visualize the future notch in the metal framework which
coincided with the location of the implant. The objective of this
impression was to record the dental and osteo-mucous support surfaces
(Figure 7A).
The metal framework was realized in the laboratory respecting the
framework layout already established (Figure 7B). The try-in of the
framework was carried out in the mouth.
This framework served as a support for a sectorial anatomo-functional
and situational impression. The first step consisted on the equipment of
the saddle with formatray resin.
The resin has been removed in front of the implant (Figure 7C).
Subsequently, the peripheral joint was modeled at the level of the edges
of the terminal saddle. Then, healing abutment was unscrewed and
impression coping was placed into the implant (Figure 7D). Anatomo
functional and situational impression was taken using polyether (Figure
7E). This rigid material allowed the implant position transfer. After
the material has set, the impression coping was unscrewed and the frame
was un-inserted.
Implant laboratory analogue was attached to the impression coping and
the casting of the impression has been carried out. Thus, the corrected
cast was obtained (Figure 7 F,G,H).
After bite recording, the teeth arrangement on wax was carried out and
evaluated intra-orally (Figure 7I). Heat-curing acrylic resin was
processed in the laboratory. In this step, locator abutment was
connected to the implant laboratory analogue and the black laboratory
sheath was used.
Locator abutment was tightened on the implant. The metal box was placed
on the female part of Locator abutment and the spacing was checked at
the level of the intrados of the prosthesis using a low viscosity
silicon (Figure 8A,B,C).
A piece of rubber dam was putted in place to prevent the resin from
melting during the chemical polymerization (Figure 8D). The
chemical-curing resin was prepared (Figure 8E) and the prosthesis was
inserted in the mouth. The polymerization takes place under occlusal
pressure.
After disinsertion of the prosthesis, the metal box was transferred to
the intrados (Figure 8F). The black sheath will be replaced by a plastic
retentive part (Figure 8G).
The patient was very satisfied with the final result (Figure 8 H,I).
Oral hygiene instructions were provided, particularly for the
maintenance of peri-implant tissues, gingival and mucosal surfaces of
the prosthesis.