Braz Dent J (1997) 8(1): 55-60 ISSN 0103-6440
| Introduction | Case Report | Discussion | References |
The use of dentures immediately after tooth removal is a common practice in dentistry especially when tooth extraction causes aesthetic problems. In the field of complete dentures, the procedure for the construction of immediate dentures permits the preparation of prostheses with the characteristics of standard dentures that can be used for a long period of time, promoting the recovery of function and aesthetic appearance without impairing patient comfort. For removable partial dentures, immediate prostheses are usually provisional for use over a short period of time while the extraction site heals. These dentures are usually made with acrylic resin and wrought wires, and in addition to compressing delicate parts of the support system, often do not provide the comfort and security needed by the patient. Immediate removable partial dentures with a metal framework are seldom used for this procedure, probably because of the difficulty in fitting the framework prior to surgery. The authors present a clinical example in which a modification of framework positioning permitted previous fitting of the framework, eliminating the possibility of lack of fit after tooth extraction, which resulted in clinical sucess 6 years later.
Key Words: Immediate partial denture, cast metal framework.
In patients that will become completely edentulous, the construction of complete dentures for immediate placement is a routine process that has been used for several decades. Thus, even though the number of patients indicated for this type of service has been reduced over the last decades, this continues to be a procedure that permits the patient to avoid the embarrassment of living without teeth while waiting for the healing of the tissues that will serve as support for the dentures (Zarb et al., 1990).
Similarly, for patients who will become partially edentulous after the extraction of damaged teeth, the construction of a provisional immediate partial denture represents a fundamental clinical measure for the prevention of aesthetic problems (Miller, 1975). In these patients, however, these provisional dentures can also be planned so that they will have a therapeutic function in addition to an aesthetic one, aiding, for example, the vertical and horizontal repositioning of the mandible in cases of loss of vertical dimension and/or when the maximal intercuspal position suggests poor positioning of the articular condyle in the glenoid fossae. These dentures are called therapeutic prostheses (Miller, 1975; Henderson and Steffel, 1979). Provisional partial dentures mainly constructed for aesthetic purposes and therapeutic prostheses must be replaced with conventional dentures during the early stages of rehabilitation. However, they need a retainer system that will guarantee comfortable use by the patient. In general, retention is provided by the intimate contact between the acrylic resin base of the dentures and specific portions of the support system, such as interdental spaces, and by the use of wrought wire clasps (Zoeller, 1973; Miller, 1975). However, despite the care taken in their construction, several problems related to these types of prostheses have been observed in practice; among them is the feeling of insecurity manifested by some patients when the provisional prosthesis becomes unstable, often because of anatomical characteristics of the patient, and exaggerates tissue compression, and conversely, the patient may feel so comfortable with the prosthesis that definitive treatment may be discontinued. This leads to the prolonged and incorrect use of provisional prostheses which may impair the entire prognosis of rehabilitation.
A therapeutic possibility that may prevent the occurrence of these two conditions is the construction of removable partial dentures with a metal framework planned for immediate use after surgery. This treatment option, however, is seldom used because the positioning of the mesh retainer for acrylic resin, commonly constructed on the crista of the residual border, prevents the testing of the framework before surgery. Thus, the dentist faces the extremely disagreeable possibility of being unable to properly seat the prosthesis after surgery if any dimensional change occurs in the master cast and/or mold, which often goes undetected until insertion of the framework. Methods proposed to solve this problem include welding the mesh retainer for acrylic resin after construction of the framework or the use of wrought loops that, initially positioned on the alveolar border after elimination of the teeth being extracted, are later folded on the crista resulting from the alveolar border after elimination of the teeth being extracted from the mold (Sykora, 1985).
We report here a clinical example and 6-year follow-up using the method of Bezzon et al. (1992) in which the palatine placement of the mesh retainer permitted a comfortable solution for anterior edentulousness practically without altering the routine of denture construction.
Examination of diagnostic casts mounted on the articulator (Figure 2) revealed that replacement of the teeth distal to the last teeth in the maxillary arch would not be necessary, so that, after extraction of the three maxillary anterior teeth, the arch would correspond to Class IV in the Kennedy classification (Miller, 1970).
On the basis of the above information, treatment was planned considering three possibilities: 1) elimination of all maxillary teeth and construction of complete dentures. We considered this to be extremely aggressive since, despite generalized bone loss, the remaining maxillary teeth presented no mobility because of the support provided by the fixed prostheses, and the gingival tissues were relatively healthy. 2) Elimination of the three anterior teeth and oral rehabilitation with a fixed prosthesis. This procedure would involve removal of all previous restorations, which were satisfactory, resulting in a costly investment for a treatment of doubtful prognosis due to the generalized bone loss. 3) Elimination of the three anterior teeth and rehabilitation with a cast removable partial denture framework with a clasp and an acrylic resin denture base which we judged to be the best for the patient.
Clinical and laboratory procedures
1. Obtain, delineate and mount the diagnostic casts on a semi-adjustable articulator (Figure 2).
2. Design the framework of the removable partial dentures with the mesh retainer shifted towards the palatine region of the teeth to be extracted (Figure 3).
3. Recontour the existing prostheses for the best placement of survey line and prepare rest seats.
4. Make an impression of the arch, preferably with the alginate, and make a master cast.
5. Transfer the trajectory of insertion from the diagnostic cast to the master cast.
6. Block out undesirable undercut and make a refractory cast.
7. Wax and invest, cast and finish the framework. Note the palatine positioning of the mesh retainer (Figure 4).
8. Try-on and fit the framework prior to surgery (Figure 5).
9. Remove the teeth to be extracted from the master cast and carefully trim the ridge, seat the framework on the master cast and mount in the articulator. Set the artificial teeth, and complete the partial denture in the usual manner. During this step, the careful trimming of the ridge permits intimate contact of the artificial teeth in the prosthesis with the residual ridge in the mouth. If ischemia occurs during placement, trim the base of the prosthesis in the proper place by grinding it with a bur.
10. Complete the surgery for extraction of the three anterior teeth and place the immediate prosthesis (Figures 6 and 7).
Clinical evaluation - 6-year follow-up
During periodic evaluation over the following 6 years, it was noted that no further procedure was necessary either for the prosthesis or the support system. Clinical evaluation showed a significant improvement in the patient's oral hygiene indicating a high degree of motivation due to the treatment carried out. This was certainly important for the clinical sucess. At all evaluations, the patient was satisfied both with the functional and the esthetic aspects of the prosthesis.
Figure 1 - Initial aspect of the patient.
Figure 2 - Casts outlined and mounted on a semi-adjustable articulator.
Figure 3 - Occlusal view of the framework with palate dislocation of the mesh for acrylic resin.
Figure 4 - Occlusal view of the wax sculpture.
Figure 5 - Clinical test of the framework.
Figure 6 - Surgical stage.
Figure 7 - Final aspect of the patient.
Contact of the base of the provisional prosthesis with areas that do not tolerate compression, such as the gingival margins, is the major reason for the early replacement of these dentures. If this is not done, the effect of uncontrolled compression is disastrous for the support system, especially considering that, in the present case, periodontal disease involved nearly all remaining teeth. Thus, the treatment protocol established permitted a satisfactory solution that reduced to a minimum the anxiety of both patient and dentist, practically requiring no changes in the standard procedures for the construction of removable partial dentures. Placing the mesh retainer in the palatine region of the arch permitted previous fitting of the framework, so that during the surgical phase only the acrylic resin base required fitting, which was of easy execution.
It should be emphasized that the form of treatment proposed for this patient, like any other rehabilitation prosthetic procedure, requires general planning so that irregularities detected in the opposite arch, for example, will not act as negative prognostic factors. The method described here permits the construction of definitive dentures which, however, requires a more careful maintenance phase than for standard dentures, as is also the case for immediate complete dentures, especially during the first few days after insertion. This maintenance phase should be prolonged in the presence of signs of alteration in the shape of support tissues because of the healing process in the operated area.
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Correspondence: Dr. Osvaldo Luiz Bezzon, Departamento de Materiais Odontológicos e Prótese, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, 14040-904 Ribeirão Preto, SP, Brasil.
Accepted January 6, 1997
Electronic publication: September, 1997