When tooth extraction is unavoidable, the resulting mutilation causes patients a great deal of anxiety that tends to be even more intense when aesthetic appearance is compromised. The problem is almost always overcome by having temporary dentures made, which are replaced by permanent dentures after the surgical area has healed.
The temporary prostheses have some advantages when compared to normal healing (without a temporary prosthesis) and later fabrication of a conventional denture. They are as follows: diminishing the magnitude of alveolar bone resorption during the first 3 to 4 months after tooth extraction, the period when this phenomenon occurs more intensively; generating more satisfactory alveolar bone in comparison with bone resulting from normal wound healing; 1-3 protecting wound healing from oral environment aggressions and promoting better healing; facilitating the patient’s social life by enhancing aesthetic appearance; preventing muscle collapse; enabling better mastication function, which improves after the first lining with a silicon material; 4 dietary changes for a shorter period of time; allowing the artificial teeth to be set up in identical positions to those of the remaining teeth.
Figure 1. Complete maxillary denture; the mandibular incisors are contained with compound resin.
Figure 2. Casts mounted in a semi-adjustable articulator with maxillary wax plane.
Figure 3. Provisional flexible removable partial denture.
Figure 4. Complete conventional maxillary prosthesis and the flexible temporary mandibular removable partial prosthesis inserted.
Figure 5. Lining the flexible temporary mandibular removable partial prosthesis.
In cases when rehabilitations are to be done with removable partial prostheses, the recommended temporary dentures are generally fabricated of acrylic resin, using stain-less steel wires to provide the required retention. 5-9 However, in clinical practice, several problems related to this type of temporary rehabilitation have appeared, such as the lack of stability resulting in the patient feeling insecure, discomfort just after insertion, aesthetics jeopardized by the appearance of metal clips, and difficulties with insertion, especially after a long surgical procedure. A conventional removable partial denture is rarely inserted immediately, because the conventional position of the retention arch prevents the metal structure from being tested before the surgical procedures. Therefore, the clinician has to face the extremely unpleasant possibility of not being able to insert the dentures after the teeth have been extracted.
In an endeavor to solve these problems, the authors describe a case report of a temporary immediately removable partial denture that was ready-made with a flexible resin, which is heat-injected under 4 tons of pressure. An important characteristic of this material is its flexibility, enabling the denture to have an excellent and more comfortable insertion.
CASE REPORT
The patient, a 50-year-old man wearing an unstable and old complete maxillary denture, and with some missing mandibular teeth, presented at the São Paulo State University, Araçatuba School of Dentistry for oral rehabilitation (Figure 1). The patient underwent intraoral and extraoral physical exams, and panoramic radiography was used to assess oral status and to detect possible residual roots, oral pathologies, or unerupted teeth. In addition, information about the patient’s general health was collected, showing he was in good medical health and a nonsmoker, and there was an absence of bruxism. His dental history data included the reasons for the missing teeth and the number of dentures previously worn, and noted that his present dentures fitted poorly and had some missing elements. A preview of his facial harmony was also observed.
At the clinical exam, loss of vestibular fornix depth was observed in the anterior maxillary region under the alveolar crest, with mobility and excessive gingival tissue. There was generalized presence of biofilm and calculus on the mandibular teeth and loss of conjunctive insertion. The mandibular incisors presented severe mobility without any possibility of performing periodontal treatment. The radiographic exam showed the presence of generalized calculus on the mandibular teeth, slight bone loss in the posterior mandibular teeth, and excessive bone loss in the anterior mandibular incisors.
The patient was instructed about proper oral hygiene at home, and treatment was performed. The mandibular incisors were contained with compound resin (Figure 1) to provide the patient with more security until the procedures before tooth extraction were performed. The posterior mandibular teeth received periodontal treatment.
On the maxillary alveolar crest, surgery was performed to gain vestibular fornix depth, and a gingival graft was inserted. A period of time was allowed for wound healing and for later fabrication of the complete maxillary denture and temporary immediate removable partial mandibular denture, which would be inserted after extraction of the mandibular incisors.
The first impressions of the maxilla and mandible were made with alginate to acquire the anatomic molds in common plaster. The mandibular mold was outlined, and the immediate removable temporary partial denture was planned. Rests were made on the mandibular teeth to support the denture, and then an impression of the mandibular arch was taken with mercaptan (Permalastic [Kerr]). A conventional functional molding technique was used for the maxillary arch, with an individual mold (Godiva [Kerr]) in a stick for peripheral sealing and zinc-eugenolic paste (Lysanda [Lysanda Odontology Products]) to take the impression of the residual ridge.
At the time the working model was obtained, the first change was noted when comparing the procedures for obtaining the conventional denture versus the flexible denture. To fabricate the conventional denture, the mold was made with a stone cast, a material with sufficient resistance to bear compression of 1 ton at the moment of muffle pressing. To produce the temporary flexible denture, the mold had to be made with a special cast to resist a pressure of 4 tons at the moment of the flexible resin injection.
After obtaining the working models, the retentive regions were relieved. The bases were made with a wax roll, and a mold of the facial arch was taken. The maxillary model was mounted in a semi-adjustable articulator (ASA; Figure 2); the maxillary-mandibular relationship was checked by measuring the distance between 2 reference points marked on the patient’s face with a skin marker pen (one on the chin and the other at the base of the nose), and then the mandibular model was mounted in the ASA.
The prosthetic teeth shade was selected, and after the teeth were mounted in the laboratory, a new clinical test was run on the 2 pairs of dentures, checking the correct vertical dimension, aesthetics and phonetics, and interocclusal contacts. The denture acrylization process then began. The conventional maxillary complete prosthesis followed the conventional inclusion period and polymerization. The temporary flexible mandibular prosthesis was included in a differential metal muffle to be adapted to the injection machine. The muffle has a hole in its structure, adapted to the nozzle of a cylinder in which the aluminium capsule containing the flexible resin is melted.
After the prosthesis was made, the mandibular incisors were surgically extracted and the conventional complete maxillary denture and the flexible temporary mandibular removable partial denture were inserted (Figures 3 and 4). The necessary occlusal adjustments were made.
The patient received instructions on oral hygiene and maintenance of the dentures to perform at home, as well as being informed about bone resorption after extractions. A follow-up schedule was established. After 2 months the mandibular prosthesis was lined with silicone (Figure 5).
After the prostheses were installed, functional tests were done, and it was observed that there was good retention and stability, as well as adequate adjustment of the prosthesis after 6 months of use. At present, a conventional removable partial denture is being made to replace the inferior temporary flexible immediately removable partial denture.
DISCUSSION
Ritterbeck, 10 a researcher who designed the flexible resin with acrylic support (Flexline), reports that the dimensional variation of the denture support made of the new flexible resin is much lower in comparison to that of the conventional acrylic resin used in microwave and hot water baths, since Flexline resin is monomer-free. The monomer-free property, in addition to being relevant as regards toxicity, positively influences the properties of this resin, because the absence of monomer trapped inside the resin avoids gap formation and consequently diminishes porosity and water sorption, which represents a percentage of 0.1%, ie, 3 times less than that of conventional resin.
The same author relates that the absence of porosity as a result of monomer release is reflected in im-proved hygiene, since biofilm adherence and bacterial calculus formation are hindered. He also points out the light weight of the denture made of flexible resin. The weight of 2 types of complete maxillary dentures mounted with the same teeth was compared. The denture made with flexible resin weighed 20 g, and the weight of the denture made of conventional acrylic resin weighed 32 g, which means more comfort for the patient. In addition to the light weight, transparency is a positive factor in Flexline resin, since light transmission is 92%, exceeding the light transmission of a conventional acrylic resin (52%). That is to say, flexible resin reproduces the color of the patient’s gingival tissue more faithfully. It dispenses with the use of metal clips on the vestibular side, enhancing its aesthetic appearance.
Temporary flexible immediate dentures have to be relined 2 months after teeth extraction, and this requires a material with good adaptation and bonding. For this purpose, silicone has excellent properties, such as good conformation and good bond to the resin. 11-13 Moreover, to avoid exaggerated tissue compression caused when the temporary prosthesis is worn for an unduly prolonged time, a conventional removable partial denture has to be made to substitute for the temporary flexible immediately removable partial denture.
CONCLUSION
The temporary flexible removable partial denture is more comfortable for the patient, fits better at the time of insertion, and it is aesthetically more favorable.
Dr. Goiato is a professor in the Department of Dentistry Materials and Prosthesis, Faculty of Dentistry of Araçatuba, University of the State of São Paulo, Brazil. He can be reached at goiato@foa.unesp.br.
Dr. Panzarini is a professor in the Department of Surgery and Integrated Clinic, Faculty of Dentistry of Araçatuba, University of the State of São Paulo, Brazil. He can be reached at panzarin@foa.unesp.br.
Dr. Tomiko is a doctorate degree student in the General Clinical Department and Periodontology, Faculty of Dentistry of Araçatuba, University of the State of São Paulo. He can be reached at celiatomiko@foa.unesp.br.
Ms. Luvizuto is a student of the dentistry course and trainees, Integrated Clinic, Faculty of Dentistry of Araçatuba, University of the State of São Paulo. She can be reached at eloaluvizuto@hotmail.com.br.