Written by Daniel E. Purvis, DDS Sunday, 31 March 2002 19:00
Provisional restorations are an important and desirable restoration in today’s practice. The advent of implant dentistry, total mouth cosmetic restorations, increased tooth life due to periodontal therapy advances, and the public’s demand for cost-effective restorative alternatives all place the provisional prosthesis in the forefront of the modern dental practice.
These factors, coupled with a prefabricated universal design, can give the practitioner a distinct advantage in executing long-term treatment plans and treating medically compromised or financially challenged patients.
|Figure 1. The stainless steel component of the reinforced resin retained fixed bridge.||Figure 2. The mechanical design of the reinforcing steel component.|
|Figure 3. The zone of attachment, which is the placement for the steel component.|
The preparations are standard class III preparations. Their placement is in the zone of attachment.4 The zone of attachment is described in Figure 3. It is determined by statistical analysis of surveyed patient models. The preps should be placed as close to the axial height of contour of the tooth as possible. Their width should be at least 2 mm and deep enough to incorporate the steel component. Survey studies reveal that the difference between the axial height of contours of anterior teeth is 2 mm. This measurement is what is used to determine the width of the double axis retention wing. Furthermore, stainless steel when freshly micro-etched increases bond adhesion. This further adds to the strength of the total restoration.
THE DIRECT EASTFLEX BRIDGE TECHNIQUE
The technique for fabricating a stainless steel reinforced resin bridge utilizes Eastflex bridge components. These components allow the fabrication and placement of single pontic bridges without the need for laboratory support. When the procedure is followed, a durable fixed prosthesis can be fabricated that can withstand a minimum of 1,200 psi. Armamentarium consists of the Eastflex bridge component selected to fit the space; appropriate handpiece(s) and bur(s) for tooth preparation; 35% phosphoric acid etchant gel; bonding agent and composite resin; curing light if light-cured resin is used; and suitable plastiform crown contoured to fit the space.
|Figure 4. Make the necessary cavity and tooth preparations to receive the steel component.||Figure 5. Prepare the space of the missing tooth.|
|Figure 6. Contour and fit the steel component into the prepared space.|
Figures 7 and 8. Prepare the plastiform crown.
|Figures 9 and 10. Invest the crown form and place it onto the space making sure it is also completely invested to the supporting steel component.|
|Figure 11. Final restoration has been finished with appropriate composite finishing equipment.|
The technique consists of the following steps:
The author and Dr. Maris J. Lans (a practitioner in Lanham, Md) have placed 150 stainless steel reinforced resin bridges and followed them from 3 months to 5 years.5 They produced the following data: 28 posterior bridges; 57 premolar bridges; and 65 anterior bridges. The total repair rate was 8%. The breakdown was: 2 posterior repairs; 4 premolar repairs; and 6 anterior repairs.
Leeson, DF. History of the Oral Structures. St. Louis, Mo: Mosby; 1987:326-328.
Travis DF, Glimacher MJ. Structure and relationship of bovine enamel to dentine. J of Cell Biol. 1964;23:447.
Lab Report No. a68347, 1999, RambleTest Labs Inc, Cinnaminson, NJ.
Eastflex Scientific Report 1997, Eastflex Inc, Indianapolis, Ind.
Eastflex Case Files 1994-1999, Indianapolis, Ind.
Lab report No.A68347, Ramble Test Labs Inc, Cinnaminson, NJ.
- RG Craig. Restorative Dental Materials. 7th ed. St Louis, Mo: Mosby; 1985: 61.
Dr. Purvis is a general dentist and full-time practitioner in Indianapolis, Ind. He can be contacted at (317) 545-6011.
Disclosure: Dr. Purvis is Vice President and on the Board of Directors of Eastflex Inc.
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