A modern approach to denture strength

As removable prosthetic technologists/technicians, we know denture base resins have certain limitations to withstanding forces that may be incurred due to individual patient indication, (para-function, malocclusion, loss of opposing dentition, lack of regular intraoral maintenance).

With all these considerations in mind it is important for the laboratory technologist/technician to provide the insurances available, to guard against failure or breakage of the prosthetics fabricated in today’s high-tech dental industry.

When these challenges present themselves, a reinforcement material is an effective and viable solution in overcoming such problematic situations. History lends itself to using a chrome-cobalt mesh casting, or prefabricated mesh screening. Now there is a remarkable 21st century material recently meeting FDA approval in the United States, and having a presence in Canada for one year.

The product is Fiber Force, a fiber reinforcement system using advanced e-glass fibers specially treated and impregnated with a light cure resin that ensures homogeneity with the processed denture base resin. Fiber Force is biocompatible and metal free with physical properties that are proven to be stronger than Cr-Co. When processed into methyl methacrylate or poly-methyl methacrylate denture base material the Fiber Force reinforcement material becomes virtually invisible and adds no extra weight to the prosthesis.

With the use of Fiber Force it is possible to enhance the strength of newly fabricated prostheses as well as while repairing prostheses in the dental laboratory. New applications for the use of Fiber Force display great benefits of increased value to the laboratory in the area of attachment cases, the implication for use in implant cases shows increasing benefit, thus improving the means of adding strength with a higher esthetic value. 

As always, to ensure the ultimate integrity of the final outcome, it is essential to follow all of the manufacturer’s instructions for use. Following the protocol to be described points out how Fiber Force is clearly an efficient and productive way to ensure added strength to denture base resins. Fiber Force requires only a few essential pieces of equipment and is a technique that is easily mastered with minimal instruction.

The following procedure demonstrates the ease in which any and all removable prosthetic dental departments can have the ability to add the insured value of the products that are produced and delivered within the dental industry.

Technique

01 First apply a thin coat of separator to the cast, and then carefully warm and adapt a thin layer of wax (0.5 mm). Cut rectangular holes into the wax in 6 areas of the palate to act as the tissue stops and maintain accurate repositioning of the cured matrix (Fig. A).

02 Using the Fiber Force pink resin, fill the holes for the repositioning markers/tissue stops (Fig. B).

03 Wearing powder-free gloves and using scissors, cut the quantity of Fiber Force mesh material required to cover the palate and ridge of the cast.

04 Carefully adapt the mesh over the wax and press lightly to adapt it onto the cast and into the fluid resin (Fig. C).

05 The Splintvac unit and the reusable silicone gasket are used to intimately adapt the Fiber Force mesh to the contours of the cast (Fig. D).

06 Position the cast into the Splintvac unit, laying the silicone gasket over the top of the main compartment. Place the o-ring of the vacuum unit to secure the gasket and allow for proper sealing (Fig. E).

07 With the tubing and the air pump connected to the main compartment, pull on the air pump, until the silicone gasket is completely and firmly over the cast (Fig. F).

08 Remove the air pump and place the main compartment with the sucked down silicone gasket into the light cure unit. Cure for the recommended period of time (Fig. G), which depends on the type of curing unit being used (usually 45 seconds to 2 minutes).

09 Once curing is complete, remove the Splintvac from the light cure unit. Disassemble the main compartment and remove the cast with the fully cured matrix from the unit.  

10 The mesh matrix must be cleaned of all wax from the spacer. This may be accomplished by using the boil-out unit, and then steamed to be completely free of all waxy residue left behind on the mesh that will inhibit proper interface with the denture base acrylic (Fig. H).

11 Trimming the Fiber Force mesh matrix to the desired size and shape is done using any type of standard scissors (Fig. I). The final cured matrix will be flexible; it should not be rigid like a cast metal framework.

12 During the curing process a thin layer of flash flows over the holes of the mesh. This layer of flash must be removed and is easily done with a small (#6 or #8) round bur (Fig. J). Care must be taken not to damage the actual mesh fibers. This step must be performed to ensure the denture base acrylic can move freely through the mesh matrix during the packing or injecting procedure.

13 The completed Fiber Force mesh matrix is now at the stage for the packing or injecting process (Fig. K).

14 Position the Fiber Force mesh matrix for final closure of the denture flask (Fig. L).

15 Palatal and tissue views of the complete maxillary denture with Fiber Force incorporated (Figs. M & N). Note the reinforcement is virtually invisible without added weight.

Conclusion

It should not be assumed that Fiber Force has capabilities limited to just removable prosthetics. It is being proven to have substantial benefits in certain fixed prosthetics applications as well. Fiber Force is a thin, lightweight material and the technique for its use is fast, easy and allows for predictable and consistent results.