Three-appointment technique to fabricate a duplicate prosthesis from the patient’s existing prosthesis

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The duplication procedure copies most of the features of the existing prosthesis [1-13]. The contour of the original prosthesis preserves the neuromuscular state of the patient. It is most appropriate when a patient is happy with their existing prosthesis but needs a new prosthesis as an alternative. [3]. This can happen if the prosthesis is broken, lost or needs to be repaired. It also avoids the hassle of going through all the stages of manufacturing the prosthesis. It preserves function and aesthetics without the need to adjust to a new set of dentures [4].

Various prosthesis duplication techniques have been mentioned in the literature [1-17]. Patients with medical conditions such as gastroesophageal reflux suffer from denture tooth attrition. In such a scenario, the recessed surface of the prosthesis is usually intact but there is a loss of vertical dimension [5]. This article describes a simple method to fabricate a duplicate prosthesis from an existing patient’s prosthesis in just three clinic visits excluding any recalls. It allowed the duplication of the intaglio surface of the patient’s dental prostheses as well as the replacement of new teeth.

A 78-year-old patient presented to the prosthodontic department with a chief complaint of inability to use her old dentures. During the conversation, she revealed that she had two sets of dentures. The patient was very comfortable with her first dentures, but the teeth were worn. This reduced its masticatory efficiency. To overcome this, she made a second set of dentures. The patient could not wear the second set of prostheses because she could not adapt to the new contours and fit. His direct request was to keep the same edge and shape of the prosthesis as the first prostheses and to replace only the teeth. She also asked to reduce her visits as much as possible.

First visit

An oral examination of the patient and the prosthesis was performed. The retention and stability of the prostheses were good but the worn occlusal surface of the teeth reduced the vertical dimension of the occlusion by 3 mm (Figure 1).

There were no undercuts present in the prosthesis. The fabrication of a duplicate prosthesis from the patient’s existing prosthesis was planned. The prostheses and vials were lubricated with petroleum jelly. Dental stone (Kala Stone, KalaBhai Karson Pvt. Ltd, Mumbai, India) was mixed and poured into half of the dental flask. The polished surface of the maxillary denture was set in dental stone (Kala Stone, KalaBhai Karson Pvt. Ltd, Mumbai, India) with denture borders at the level of the dental stone. The second section of the vial was placed over the first section. Vaseline was applied to the recessed surface of the prosthesis and dental stone (Kala Stone, KalaBhai Karson Pvt. Ltd, Mumbai, India) to easily retrieve the prosthesis. The vial was then filled with the dental stone. The two halves of the vial were separated and the prosthesis was retrieved once the setting reaction was complete. The same procedure was followed for the mandibular prosthesis (Figure 2).

Vaseline (Vaseline, Hindustan Unilever Pvt. Ltd, India) was applied to teeth and dental stone impressions (Kala Stone, KalaBhai Karson Pvt. Ltd, Mumbai, India). Melted wax was poured into the tooth impressions (Figure 3).

The mold space was then filled with self-cured acrylic resin (DPI RR Cold Cure, Dental Products of India Ltd, Mumbai, India) to paste-stage consistency. Separation medium was applied and the second half of the vial was pressed over the first. The vials were secured with a rubber band. The model prosthesis was separated from the vial and the excess material was cut off at the end of the polymerization (Figure 4).

Since the casts were intact, they were trimmed to size.

The jaw relationships were recorded by adding dental wax to the occlusal surface of the prosthesis. The prostheses with precise jaw relationships were then mounted on a medium value articulator. The patient’s maxillary prosthesis was removed and a model prosthesis was inserted (Figure 5).

Dental wax (DPI Modeling Wax, Dental Products of India Ltd.) was added and adjusted to obtain a correct occlusal plane. The setting of the maxillary teeth was completed with the patients mandibular prosthesis as a guide (Figure 6).

After the placement of the maxillary teeth was completed, the patient’s mandibular prosthesis was removed and a trial mandibular prosthesis was inserted. The arrangement of the mandibular teeth is complete (Figure seven).

Second visit

Once the try-in was accurate, final impressions were made using a light-bodied elastomeric impression material (Express, 3M ESPE, St. Paul, MN). The closed mouth technique was followed to maintain precise tooth relationships during the impression procedure. It was then cast in dental stone (Kala Stone, KalaBhai Karson Pvt. Ltd, Mumbai, India). The dentures were treated with thermosetting acrylic resin (DPI Heat Cure, Dental Products of India Ltd.) according to the manufacturer’s instructions.

Third visit

Dentures with the correct vertical dimension of occlusion and a duplicated tissue surface were delivered to the patient (Figure 8).

During the follow-up visit, the patient was satisfied with the function and aesthetics of the prosthesis (Figure 9).

Duplicate dentures were first made in 1960 for use as replacement dentures [1-2]. Getting used to the new fit is an ongoing struggle for older patients. Dissatisfaction with full dentures is a known problem and nearly 25% of denture wearers have serious problems with their dentures. [15-16]. In this case, the patient was not satisfied with her two old dentures. It is very important to make a detailed examination of the existing prostheses. They provide a great clue at every stage of processing [17]. The patient was comfortable with her first dentures, but the teeth were worn. This reduced its masticatory efficiency. To overcome this, she made a second set of dentures. The patient could not adapt to the new fit of the prosthesis. The patient’s direct request was to keep the same denture edges and adjustments as the first set of dentures and only replace the teeth. She also asked to reduce her visits due to the longer travel time from her home. She was ready to wait all day and do as many steps as possible. Considering all the factors, duplicate prostheses were planned for the patient, which would be simple, quick and less clinically and technically difficult. The patient did not have to adapt because the tissue surface was duplicated. It also improved neuromuscular coordination, reduced the number of visits, and reduced clinical and laboratory steps.

There are several techniques mentioned in the literature for making duplicate prostheses. [1-17]. Metal denture vials are readily available in the dental setup to perform the duplicating process. If duplicating vials are not available, the tray technique can be used [13].

Irreversible hydrocolloid and silicone impression material can also be used as a duplicating material [9,12]. The patient had a specific request regarding the exact duplication of the fit as well as the denture edges of an old denture, so a washout impression was taken with the patient’s denture. No overextension was present. When the wax template was made, the model was completely intact. The same model was used to mount the occlusal edges on an articulator.

Patients’ dentures had worn occlusal surfaces, so non-anatomic teeth were used to prevent the denture from locking or moving during function. On the first day, the patient had to wait a few hours to complete all the clinical steps. On the second visit, i.e. the next day, the try-on and wash impression was completed. During the third visit, complete dentures were delivered to the patient. Duplicate prostheses were treated in three visits instead of the normal five visits.

Duplicate dentures provided better aesthetics and chewing efficiency. The reduced vertical dimension has been corrected with the new jaw relationship registration. Finally, the copy prostheses incorporated the duplicate tissue surface of the old prostheses and improved the chewing function of the new prostheses.

For geriatric patients, the prosthesis copying technique is a simple and inexpensive procedure that duplicates soft tissue contours. The duplicated tissue surface adds greater adaptability to new prostheses in terms of function and aesthetics. In just three visits, the prostheses were successfully delivered to the patient.

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