International Journal of Oral Care and Research

: 2022  |  Volume : 10  |  Issue : 4  |  Page : 94--102

A simple, smart, and convenient way of fabricating a hollow maxillary complete denture: A case report

Riddhi Sharma, Naveen Oberoi, Ravpreet Singh, Jaspreet Singh 
 Department of Prosthodontics and Crown and Bridge, BJS Dental College, Hospital and Research Institute, Ludhiana, Punjab, India

Correspondence Address:
Dr. Ravpreet Singh
Department of Prosthodontics and Crown and Bridge, BJS Dental College, Hospital and Research Institute, Mohalla Mata Rani, Near Jeeta Singh Tubewell, Khanna, Ludhiana, Punjab 141401


Residual ridge resorption is a very common phenomenon observed in edentulous patients over a certain span of edentulism. Though it occurs more rapidly in mandibular arch than in maxillary arch, severely resorbed maxillary ridges with increased inter-ridge distance often lead to difficulty in prosthetic rehabilitation. This case report describes an easy yet accurate method for fabrication of a hollow maxillary complete denture using super-absorbent polymer as a spacer for the hollow cavity using a single flask technique.

How to cite this article:
Sharma R, Oberoi N, Singh R, Singh J. A simple, smart, and convenient way of fabricating a hollow maxillary complete denture: A case report.Int J Oral Care Res 2022;10:94-102

How to cite this URL:
Sharma R, Oberoi N, Singh R, Singh J. A simple, smart, and convenient way of fabricating a hollow maxillary complete denture: A case report. Int J Oral Care Res [serial online] 2022 [cited 2023 Mar 24 ];10:94-102
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The residual ridge is that portion of residual bone and its soft tissue covering that remains after the removal of teeth. The resorption of residual ridge is chronic, progressive, and irreversible process which is affected by anatomic, prosthetic, metabolic, functional, and other systemic factors.[1] The severe resorption of maxillary ridge leads to difficulty in restoring the teeth in a certain manner due to a narrower more constricted residual ridge, decreased supporting tissues, and large restorative space between maxillary and mandibular residual alveolar ridges.[2],[3],[4] The increased inter-ridge distance often results in bulky maxillary complete denture that further decreases the retention and stability owing to the gravitational pull and leverage forces on the prosthesis, although not universally accepted.[5],[6] It has been suggested that reducing the weight of prosthesis is beneficial for the success of maxillary obturator with large maxillofacial defect.[7],[8],[9]

Traditionally, various methods have been used to improve the retention and stability of complete dentures in cases of residual resorbed ridges that included the use of implants, the use of magnets, modified impression techniques, intramucosal inserts, suction discs, and lightweight dentures.[3],[4]

Chris[10] reviewed the effect of the prosthodontics treatment on alveolar bone loss and concluded that implant-supported fixed prosthesis to replace missing teeth in completely edentulous patients is a highly successful treatment but implants are also not immune to bone loss. Riley et al.[11] in their study suggested that magnets provide a useful method for attaching dental prosthesis to retain either roots or osseointegrated implants but its use is limited due to the high susceptibility of magnets to corrosion in the presence of saliva which eventually leads to loss of magnetism and failure of the prosthesis. Goncalves et al.[12] suggested the use of intramucosal inserts for improving maxillary denture retention, but the procedure may not be acceptable to the patient as it requires surgical intervention. Suction discs and springs can also be used to improve the retention of prosthesis, but they serve no useful purpose and may also prove to be disadvantageous due to constant irritation caused to mucosa and extreme restrictions posed during lateral movements.

The weight reduction approaches have been achieved using a solid three-dimensional spacer including dental stone, cellophane-wrapped asbestos, silicone putty, gauze rolled and coated with light body silicone, modeling clay, thermocol, and caramel, which have been reliably used to fabricate a lightweight denture. Moreover, there are two techniques—single flask technique and double flask technique—for the fabrication of a hollow prosthesis.[13]

Fattore et al.[14] used a variation of a 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 then attached using heat-polymerized resin. Holt processed a shim of acrylic resin over the residual ridge and used a spacer. The resin was indexed and the second half of the denture processed against the spacer and shim. The spacer was then removed and the two halves luted with autopolymerized acrylic resin using the indices to facilitate positioning. O’Sullivan et al.[15] described a modified method for fabricating a hollow maxillary denture. A clear matrix of trial denture base was made. The trial denture base was then invested in the conventional manner until wax elimination. A 2 mm heat-polymerized acrylic shim was made on the master cast, using a second flask. Silicone putty was placed over the shim and its thickness was estimated using a clear template. The original flask with the teeth was then placed over the putty, and the processing was carried out. The putty was later removed from the distal end of the denture, and the openings were sealed with autopolymerizing resin. Chaturvedi et al.[16] used the dough of dental plaster—pumice and sugar syrup rolled and placed it over heat-cured record base to act as a spacer. Heat polymerizing resin was then mixed, packed, and processed for 7–8 h. Two small openings were made with bur into denture base distal to the most posterior teeth. Dental plaster–pumice–sugar syrup paste was then removed by scraping and putting it in water. This opening was later closed with autopolymerizing resin. Shetty et al.[17] used a denser thermocol and placed it over the roughened acrylic shim along the ridge and luted with cyanoacrylate. Aggarwal et al.[18] used lost salt technique. Half of heat cure in the dough stage was positioned accurately over the dewaxed mold and salt crystals were placed over it. Above that, the remaining heat cure resin was packed. Two holes were made in the thickest palatal area. All the residual salt crystals were removed by flushing water with a high pressure syringe through the holes. Escape holes were closed with autopolymerizing resin.

This case report elicits an easy and accurate method for the fabrication of a hollow maxillary complete denture using super-absorbent polymer (SAP) as a spacer for the hollow cavity using a single flask technique.

 Case Report

A 63-year-old male patient reported to the Department of Prosthodontics and Crown and Bridge, Baba Jaswant Singh Dental College, Hospital and Research Institute, Ludhiana, Punjab, India with the chief complaint of missing teeth in upper and lower arch and difficulty in eating since 10 years. History revealed that the patient lost his teeth due to the periodontal reasons.

On examination, it was noted that patient had atrophic maxillary and mandibular ridges with increased inter-ridge distance. Labial mucosa, buccal mucosa, hard palate, soft palate, and floor of the mouth were normal. A thorough medical and dental history was elicited from the patient followed by clinical and radiographic examination. Various treatment modalities were explained and discussed with the patient including pre-prosthetic surgery followed by conventional complete denture, implant-supported prosthesis, and conventional complete dentures. Pros and cons of all were explained to the patient and due to the cost factor involved, it was planned that hollow maxillary denture and conventional mandibular denture prosthesis will be fabricated.


Make a definitive impression of the maxillary ridge and steps for the conventional complete denture fabrication were followed till the try-in denture stage.

Indexing was done by incorporating V-shaped notches using a conical bur at three sites on the land area of the maxillary cast and the waxed maxillary denture was sealed to the master cast.

The maxillary trial denture was duplicated with the irreversible hydrocolloid impression material (Septodont, Plastalgin) and poured in Type III dental stone (Kalstone, Kalabhai Pvt., Ltd., Mumbai, India) to obtain a working cast [Figure 1].

A 2 mm thick template of the duplicated stone cast was made using a thermoplastic transparent sheet (BIOPLAST Scheu Dental GmbH, Iserlohn, Germany) with the help of a heat and vacuum press (BIOSTAR Scheu Dental GmbH) to obtain the trial denture external contours [[Figure 2] and [Figure3]].

Modeling wax of 2 mm thickness was adapted over the master cast to ensure uniform and adequate thickness of resin all around the planned hollow cavity [Figure 4].

The clear matrix was placed on the definitive cast using the indices in the land area as seating guides [Figure 5]. Three endodontic files with a rubber stop were used to measure the space between the matrix and the tissue surface of the cast (two in the posterior region and one in the anterior region) [Figure 6] and [Figure 7].

The length of the file from the rubber stopper was measured with the help of a ruler [Figure 8] and [Figure 9] and a putty index was made [Figure 10]. Vinyl polysiloxane putty [Aquasil, Dentsply Corporation, Germany] was mixed and adapted on the base and shaped to the approximate contours of the matrix. The polymerized putty was shaped with a BP blade no. 15 to leave 2–3 mm of space between the putty and matrix. An additional 1 mm space was provided over the tooth portion of the denture. The putty was fixed to the base using cyanoacrylate.

The maxillary trial denture was invested and dewaxed in the conventional manner [Figure 11] and [Figure 12].

During packing, the heat cure acrylic resin dough was packed in two stages. Initially, the first dough mix was placed over the tooth surface and the hollow trough was created with the help of the putty index. Then, the putty index was removed and hollow trough is formed [Figure 13] and [Figure 14].

The SAP [Figure 15] and [Figure 16] was injected in this hollow trough with the help of a syringe to fill it completely [Figure 17] and [Figure 18] and the second dough mix was placed over it to complete the packing and the flask was kept for bench curing [Figure 19].

Curing was completed with a short curing cycle in a conventional manner.

After retrieving dentures from the flask, two holes were drilled with the help of a round bur and straight micromotor handpiece on the posterior cameo surface of the denture [Figure 20] and with the help of a three-way syringe, the air was sprayed from one side to remove the SAP from the other side of the hollow cavity [Figure 21].

Furthermore, the material was retrieved with the help of salt water. The salt water turns SAP into liquid state from gel state and easily flows out of the hollow cavity [Figure 22].

Then the prepared holes were closed with the help of self-cure acrylic resin and the denture was finished and polished in a conventional manner.

In comparison, the weight of hollow prosthesis and ideal denture was measured [Figure 23] and [Figure 24] and also the hollow denture floats when kept in water whereas the conventional denture sinks [Figure 25] and [Figure 26].{Figure 1} {Figure 2} {Figure 3} {Figure 4} {Figure 5} {Figure 6} {Figure 7} {Figure 8} {Figure 9} {Figure 10} {Figure 11} {Figure 12} {Figure 13} {Figure 14} {Figure 15} {Figure 16} {Figure 17} {Figure 18} {Figure 19} {Figure 20} {Figure 21} {Figure 22} {Figure 23} {Figure 24} {Figure 25} {Figure 26}


The prosthetically driven treatment of geriatric patients with severely resorbed ridges always becomes a herculean task for the clinician. Though the choice of rehabilitation in such cases should be tooth-supported, implant-retained, and tissue-supported overdentures with ridge augmentation, due to systemic illness associated with increased age, more prognostically favorable treatment option is to rehabilitate them with conventional complete dentures.[19] To obtain acceptable retention, stability and support, utilizing the maximum denture-bearing area along with modification in complete denture processing and occlusion, may deliver superior results in such patients. The weight of maxillary dentures is often a dislodging factor. Thus, reducing the weight of the maxillary denture has been attempted for years, to enable the clinician to provide the patient with satisfactory results.[19],[20]

Creating a space within the denture is most effectively studied for obtaining the reduction in weight, which led to the development of hollow cavity inside the denture, hence the term hollow denture.[2],[19] Various materials used for the hollowing of denture include vinyl polysiloxane putty, thermocol, plaster-pumice and sugar syrup, salt crystals, play dough (modeling clay), autopolymerizing acrylic resin shell, cellulose balls, poly-acrylic fibers, bean balls, surgical catheter, orthodontic wire, gelatin, glycerin soap, caramel, and vacuum-formed thermoplastic sheet with salt. Some of the materials such as vinyl poly-siloxane putty pose a problem during the procedure as the retrieval of such material is difficult.[2],[3],[20] Materials that are easy to remove from the cavity, such as salt, caramel, and glycerin soap, proved effective for the fabrication of hollow denture till the SAPs were discovered and taken into consideration.

SAPs are three-dimensional cross-linked polymer networks that can absorb and retain large amount of aqueous fluid (up to 300 times) compared with its dry weight.[21] SAPs having high swelling capacity along with good water retention ability and biodegradability enable them to possess potential applications in various field such as hygiene products (e.g. baby diapers, adult diapers, and sanitary napkins), biomedical healthcare products (e.g. drug delivery systems and wound dressing), agriculture (in holding soil moisture), horticulture, waste water treatment, and self-healing concrete.[22] SAPs are mainly divided into natural SAPs and synthetic SAPs. Commercially available SAPs are synthetic resins that are mainly polymerized using acrylic/vinyl monomers such as acrylic acid, acrylamide, vinyl alcohol, and acrylonitrile. Even though synthetic SAPs currently available in the markets are biocompatible and have no direct threat to human life, disposal of such non-degradable material waste is a source of various environmental problems. Therefore, natural polymer-based SAPs have received great attention that they are degradable via multiple mechanisms of actions including enzymatic reactions, microbial attack, and hydrolysis. SAPs based on natural polymers (e.g. cellulose, chitosan, starch, and alginate) are renewable, biodegradable, and non-toxic in nature.[23] However, the main challenge in the area of biodegradable SAPs is to synthesize fully degradable SAPs that would rapidly and reversibly absorb water and have good mechanical strength. Major limitations of biodegradable SAPs are its poor mechanical properties and high-speed degradation.[22],[24]

The technique described has advantages over the earlier used methods for hollow denture fabrication. Leakage and difficulty in maintaining resin thickness are the problems usually encountered in previous techniques which is not a problem with SAPs due to its easy retrievability. There is minimal extra-laboratory procedure, there is no tedious effort to remove the spacer material, auto-polymerizing acrylic resin shell also adds to the strength of the denture, color of autopolymerizing acrylic resin can be matched with heat-cured acrylic resin thus enhancing esthetics, and there is no chance of leakage. The technique is economical and provides even space all around.

Further research in the field of materials and techniques is required for the development of less time-consuming and cost-effective methods to provide patients with hollow dentures.


A simple and unique method is highlighted for the fabrication of lightweight dentures using an SAP, which proves to have certain practical advantages over the previously used matrix materials. Hollow dentures considerably reduce the weight of the prosthesis, which in turn improves retention, stability, and support. Also, it helps to preserve underlying tissues and bone by preventing transmission of detrimental forces directly on them. Hence, it is a promising and economical way for the patients who are reluctant to go for invasive procedures or have serious systemic conditions.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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