Floating Denture – A Solution for Heavy Maxillary Prosthesis: A Case Report

Introduction

Geriatric patients with a set of complete dentures, over a period of time, face a common problem of residual ridge resorption. Rehabilitation of such ridges is a challenging task for a prosthodontist/dentist. Retention, stability, and support are vital for a successful complete denture.

Severe resorption may lead to a narrow and constricted maxilla, reduced denture supporting area, and an increased inter-ridge distance. The resorption rate in the mandibular arch is higher compared to the maxillary arch. However, an atrophic maxilla which has a larger inter-ridge distance poses a clinical challenge for the fabrication of a successful maxillary complete denture. Increased inter-ridge distance may result in a heavy maxillary complete denture, thus reducing its retention and resistance.

Several approaches for developing hollow maxillary or mandibular complete dentures by creating a solid three-dimensional (3-D) spacer are documented in the literature. This is achieved by with the help of dental stone, cellophane-wrapped asbestos, silicone putty, or modeling clay. These methods are used during laboratory processing to exclude the base material from the planned hollow cavity of the denture. The denture is assembled around a 3-D spacer and allowed to polymerize. After polymerization, the solid spacer is discarded and the separate parts of the denture are put together using an auto-polymerizing acrylic resin. The main disadvantage of such techniques is that the junction between the 2 formerly polymerized portions of the denture occurs at the borders of the denture, which increases the risk of seepage of fluid into the denture cavity. Furthermore, this junction is a common site for post-insertion adjustment, increasing the probability of leakage. Another disadvantage is that it is difficult to ascertain the resin thickness within the cope area.

This clinical report describes a distinctive, meticulous technique for the fabrication of a weightless maxillary prosthesis using a catheter tube and orthodontic wire, which is a “catalogue” for achieving uniform thickness of the denture base material around the unfilled cavity.

Case Report

A 63-year-old moderately-built male patient with no significant medical history reported to the Department of Prosthodontics Crown & Bridge, Institute of Dental Sciences College and Hospital, Bangalore, with the chief complaint of difficulty in deglutition and speech due to missing teeth. He had been wearing a denture for 4-5 years.

Intraoral examination revealed severely resorbed maxillary and mandibular edentulous ridges. Due to the highly resorbed maxillary ridge, the maxillary denture was loose. To overcome this problem a hollow maxillary complete denture with a regular conventional mandibular complete denture was planned. The following steps were followed for the fabrication of hollow complete dentures:

• A trial maxillary denture was fabricated, followed by its de-waxing. The height of the maxillary ridge was checked using a ruler before the de-waxing procedure (Fig. 1).
• After de-waxing, a coating of water-soluble alginate was applied all over the denture-bearing area except the teeth.
• Considering the strength of the denture, 2 mm thickness of the denture base and 2 mm distance from the saddle part of the tooth was subtracted from the total distance, which would determine the trough space.
• A catheter (8 French gauge) was taken and cut into two parts, followed by placement of an 18-gauge stainless steel wire inside the catheter for maintaining the stability of the tubing. The catheter was then stabilized and placed over the ridge area using cyanoacrylate (Fig 2).
• A trial closure was done. Care was taken not to perforate it.
• The upper portion of the flask was re-seated and checked for complete closure. The permanent denture base material was then packed in the space, followed by processing of the denture.
• The dentures were then retrieved and finished.
• Post finishing of the upper denture, two orifices were made on the distal aspect of the denture with the help of a round bur.
• The catheter with the wire was pulled out through the orifice using a dental plier.
• The auto-polymerizing acrylic resin was used to close the orifices
• The dentures were then polished in a conventional manner and later placed in water for evaluation of the seal (air bubbles should not be evident after immersing the denture in water) (Fig 3).
• Finally, they were inserted in the patient’s mouth (Fig 4).

Discussion

The denture-bearing ability of severely resorbed ridges is poor and reduced. The problem is compounded by the amount of denture base material in the final prosthesis. The weight of the prosthesis is reduced in a hollow denture.² This method has an edge over the previous techniques. In this case, a hollow space was created easily by removing the catheter tubing along with the wire and making a single opening for retrieval of the material, which in turn resulted in less patch work. Previously, elastomers were used for the fabrication of hollow dentures. The other viable options would be getting an implant-retained prosthesis or having a preprosthetic surgery to improve the denture foundation, but it may not be possible in all cases due to factors like cost and systemic diseases. O’Sullivan et al⁵ described a modified method for fabricating a hollow maxillary denture using an elastomeric material of putty consistency. However, withdrawal of the elastomer from inside the space, especially from the anterior region, was exceedingly difficult.^2-4

Advantages

• Cost effective.
• Improved stability (reduces or eliminates prosthesis movement).
• Light in weight.
• Reduction in soft tissue abrasions.

Disadvantages

• Snapping of the denture.

Precautions

• There should be adequate thickness of the resin around the cavity.
• The long seated junction creates a site of potential leakage and discoloration over a period of time.
• Instructions should be given to the patient regarding the denture.

Summary

Unlike conventional complete maxillary dentures, hollow maxillary dentures significantly reduce the bulk of the prosthesis and also do not exert harmful pressure on the underlying tissue and supporting bone. The technique described in this paper eliminates the need for a spacer and also controls the thickness of the acrylic resin occupying the hollow portion, resulting in a lighter prosthesis.

Conflict of Interest

None.