|Year : 2015 | Volume
| Issue : 1 | Page : 43-46
A revised technique for fabrication of hollow mandibular denture: A solution to severely resorbed residual ridge
Varun Baslas1, Simranjeet Kaur1, Kamleshwar Singh2, Himanshi Aggarwal2, Pradeep Kumar2
1 Department of Dentistry, FH Medical College, Tundla, India
2 Department of Prosthodontics and Dental Material Sciences, F.O.D.S, K.G. Medical University, Lucknow, Uttar Pradesh, India
|Date of Web Publication||2-Feb-2015|
A-2 Cottage, LRH, KGMC, Lucknow, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Purpose: Prosthodontic rehabilitation of elderly patients with severely resorbed ridges is difficult due to compromised ridge height, increased inter-arch distance and altered insertion of associated jaw muscles. Planning dentures in such cases often require dentures that are lightweight to reduce the risk of further ridge resorption, which could otherwise complicate the situation. The purpose of the present technique is to fabricate a light weight lower denture by a revision of previously described technique in the literature.
Materials and Methods: This article elucidates a simple technique for the fabrication of lightweight denture (hollow denture) in elderly patients with severely resorbed mandibular ridge. The minimum thickness of denture base acrylic resin for structural durability is ensured by a wax shim of 2 mm. The adequate hollow space indenture for optimal weight reduction is created by condensation silicone impression material.
Conclusion: Condensation silicone putty material can be successfully used as a spacer for hollow dentures to combat severe ridge resorption.
Keywords: Hollow denture, light weight denture, resorbed ridges
|How to cite this article:|
Baslas V, Kaur S, Singh K, Aggarwal H, Kumar P. A revised technique for fabrication of hollow mandibular denture: A solution to severely resorbed residual ridge. Saudi J Oral Sci 2015;2:43-6
|How to cite this URL:|
Baslas V, Kaur S, Singh K, Aggarwal H, Kumar P. A revised technique for fabrication of hollow mandibular denture: A solution to severely resorbed residual ridge. Saudi J Oral Sci [serial online] 2015 [cited 2021 Jul 24];2:43-6. Available from: https://www.saudijos.org/text.asp?2015/2/1/43/150597
| Introduction|| |
Following the loss of natural teeth, residual ridges undergo reduction in their size at varying rates in different individuals and in the same individual at different times.  It has been shown that the mean ratio of anterior maxillary ridge resorption to anterior mandibular ridge resorption is approximately 1:4. , The mandible even after a dramatic early bone loss continues to show a steady resorption rate of approximately 0.4 mm/year, creating a more serious clinical problem.  As resorption progressed, mandibular arch flares with resultant large interarch space and decreased supporting tissues. For many years, mandibular dentures were made bulkier aid in retention and stability. ,, However, patients often complained of soreness and looseness of dentures overtime as a result of residual ridge compression and resorption. Studies have shown that denture stability and retention can be improved by adequate fit of the denture base area without the need of extra weight to the denture. , In general a heavy denture, whether maxillary or mandibular, is likely to cause poor denture bearing ability. Even though, it is suggested that gravity and the additional weight to the mandibular complete denture may aid in the prosthetic retention, it is not a universally accepted one. Ohkubo and Hosoi also concluded from their study that the weight of a mandibular denture does not affect its retention or stability.  Some criticism also arose from the fact, that extra weight would cause accelerated resorption of the residual ridge. 
The choice of rehabilitation for elderly patients with severely resorbed mandibular ridge can be implant supported prosthesis, ridge augmentation procedures or vestibuloplasty. However, many times, patients with such a problem have many systemic illnesses. Hence, the only option for rehabilitation are conventional complete dentures, by either modifying the impression technique to get maximum denture bearing area or modifying the weight of denture by making it hollow to alleviate the excessive pressure on the already resorbed ridge. This article describes a technique for fabrication of hollow mandibular denture, using condensation silicone material as a spacer.
| Materials and Methods|| |
- Do all the steps for fabrication of complete denture by conventional means up to the trial denture stage. 
- Duplicate the trial denture in irreversible hydrocolloid (Zelgan 2002; Densply, Gurgaon, Haryana, India) and pour the impression in dental stone (Prevest; Denpro, Jammu, India). Make a clear template of the stone cast, using a 0.5 mm thermoplastic sheet.
- Process the trial denture through wax elimination stage in the conventional manner in flask A.
- Adapt a wax shim of two layers of baseplate wax (Link dental; MDM, Delhi, India) to the definitive cast in the drag of the flask a [Figure 1]a. Place cope of flask B over the drag of flask A and invest the wax shim. After wax elimination, pack the invested flask with heat-polymerized acrylic resin (PMMA; Trevalon, Dentsply India Pvt. Ltd., Gurgaon, India) and process.
- Open the flask. Polymerized denture base acrylic resin can be seen attached to the drag of the flask A [Figure 1]b.
- Now adapt two layers of baseplate wax (2 mm thick) over the teeth in the cope of flask A [Figure 2]. Mix condensation silicone putty (Zhermack; Badia Polesine, Italy) and place it over the adapted baseplate wax. Close flask A with its own drag and cope to acclimatize the mixed putty in the available space. Excess spacer will seep through as flash which has to be cut 2 mm within the polymerized denture base thereby, avoiding a gap between the heat polymerized denture base in Drag A and the two thickness baseplate wax in cope A.
- Open the flask after the putty has fully set. Putty can be seen attached to the polymerized acrylic resin in the drag. Silicone putty cavity form can be easily separated from acrylic resin denture base and its thickness can be measured with the help of an endodontic reamer. The silicone putty cavity form ensures a uniform measurable hollow cavity leaving 2 mm of acrylic resin both on cameo and intaglio surface of the mandibular denture [Figure 3].
- Place the clear thermoplastic template that has been made in the beginning from trial denture base on the polymerized acrylic resin denture base with silicone putty cavity form to ensure an appropriate space of 2 mm for acrylic resin on the cameo surface.
- Carefully remove the previously adapted baseplate wax from the resin teeth in the cope of flask A.
- Create a very small slit on the top half of silicone putty with a sharp bard parker knife taking care not to incise its full depth for the easy retrieval afterwards. Apply separating media over the putty.
- Pack a flask A with heat polymerizing acrylic resin and process the denture in the usual manner.
- Finish the denture in the standard manner. Cut two openings with a bur into the denture base distal to the most posterior teeth [Figure 4]. Remove the condensation silicone putty by pulling it with an instrument.
- Clean and disinfect the hollow cavity. Close the denture openings with an autopolymerizing acrylic resin (PMMA; Trevalon, Dentsply India, Pvt. Ltd., Gurgaon, India).
- Polish the denture in the conventional manner. Adequate seal of the denture openings can be verified by immersing the denture in water. No bubbles ensure the proper seal.
|Figure 1: (a) Wax shim adapted over the definitive cast in drag of flask A. (b) Processed acrylic intaglio portion attached to the cast in drag of flask A|
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|Figure 3: Silicone putty spacer with measurements over the processed acrylic resin denture base after opening of flask A|
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|Figure 4: Processed denture with small openings to facilitate removal of silicone putty|
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| Discussion|| |
Several techniques have been described in the literature for creating hollow cavities in dentures and obturators. ,,,,,,,,,, Nakamura was the first who refused the concept of weighted denture.  For the first time, a technique by using two split denture flasks for the fabrication of hollow mandibular denture was described by Holt, and it reduced the weight of an acrylic denture by as much as 25%. 
Fattore et al. used a variation of the double flask technique for obturator fabrication by adding heat polymerizing acrylic resin over the definitive cast and processing a minimal thickness of acrylic resin around the teeth using a different drag. Both portions of resin were attached using a heat polymerized resin. 
Various techniques have been described in the literature for the fabrication of hollow cavity of the prosthesis using dental stone, , cellophane wrapped asbestos,  silicone putty, , and modeling clay  as spacer materials. The major drawback of these techniques is an intersection that forms the borders of the denture. This weak intersection area is often the site for adjustment during the postinsertion appointment thereby increasing the risk of leakage. It is also difficult to judge or measure the volume and uniformity of hollow cavity or resin thickness in such a denture.
The technique described in this article has many advantages over previously described techniques ,,,,,,,,,, for hollow denture construction, which are as follows:
- Alleviates the chances of leakage from the interface, and difficulty encountered in the removal of the spacer from the hollow cavity.
- Whole of the denture except a small window in the area, which usually does not need adjustment at the postinsertion appointment is made of heat polymerized acrylic resin, which ensures structural durability and strength.
- Dimensions of the hollow cavity can be measured, and a uniform thickness of the acrylic resin denture base can be ensured with this technique.
- Silicone putty used in previous techniques  was roughened with a bur to give desired contour to hollow cavity, which often led to its adherence to acrylic resin and difficult retrieval, whereas in the present technique, silicone putty takes the desired shape and contour by itself when the flask is completely closed. Furthermore, the applied separating media and slit made in the putty helps in its easy retrieval after processing.
| Conclusion|| |
A simple, modified and standardized technique for the fabrication of hollow mandibular denture to combat severe resorption of residual ridge has been described. The condensation silicone is used as a spacer, ensuring a uniform thickness of the acrylic resin denture base to prevent leakage and deformation while providing strength. Closure of the denture flask facilitates shaping of the silicone spacer. An easy method for the retrieval of spacer has been outlined. This technique is particularly useful for geriatric patients.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]