| |
| Temporization Tips for Today's Advanced Aesthetic Restorations |
As seen in "Doctor of Dentistry Magazine", January 2001.
When temporizing for today's less invasive, more cosmetic restorations, new twists need to be placed on proven techniques. Placing smaller temporary restorations with conventional means usually results in the premature loss of the provisional, leading to problems that can compromise your final results.
With more aesthetic options available to both the clinician and the patient than ever before, one area that is often overlooked in clinical discussions is how to temporize the prepared teeth while the final, permanent cosmetic restorations are being created at the laboratory.
In the case of anterior laminate veneers, many patients may only proceed with treatment contingent on the assurance that their teeth would not remain unsightly between the preparation and final cementation appointments (figure 1). With this in mind, several techniques have been developed to ensure the patient's concerns are addressed. One technique advocates bonding to only a small portion of the enamel, usually in the middle of the prepared tooth. This etched area should be approximately 3mm in diameter.
After the impressions and bite record are taken, the teeth should be first washed and disinfected with a .2% chlorhexidine solution and any areas of exposed dentin sealed with a bonding agent (it is advisable to use an older generation bonding agent, as many of the newer materials also contain a primer and will create too aggressive a bond). The bonding agent will also help reduce the incidence of post-operative sensitivity.
The selected areas in the centre of the prepared teeth can now be etched with a 35% phosphoric acid gel (figure 2). A small amount of bonding agent is placed only on this area. The temporary veneers can now be built-up, contoured with diamonds, and polished with disks directly on the tooth. One can consider using a temporary acrylic or a base of light cured temporary material. For even greater security, your material of choice can be added to the interproximal areas to help lock the temporary veneers in place.
There are two key items to consider when temporizing for veneers. Firstly, the gingival marginal areas of the temporaries must be accurate, smooth, and highly polished. This will prevent plaque from accumulating which can cause the gingival tissues to retract, thus exposing a slightly subgingival margin or a discoloured root surface. The second area of concern is the occlusion. There should not be any occlusal loading on the prepared teeth or on the incisal surfaces of the provisionals. Improper occlusal contacts can lead to a bond failure resulting in the loss of the temporary veneer.
A modification of the aforementioned technique involves the use of a diagnostic mock-up. Upon approval of a diagnostic wax-up, a thin, clear plastic stent can be made (figure 3). The stent has two distinct advantages, by trying in the stent over the prepared teeth, the clinician can assess if enough labial or incisal reduction has been done for the laboratory to achieve the desired cosmetic result. Also, the stent can act as a matrix for the fabrication of temporaries. The stent can be filled with your choice of temporary restorative material and placed onto the prepared teeth. Auto-polymerizing materials will set in place while light curing can be achieved though the stent's plastic matrix.
Using either method, the temporary material can easily be removed at the insertion appointment, using an interproximal carver.
Not only do these techniques provide an aesthetic provisional, but they also help to prevent tooth sensitivity and in cases of prior orthodontic treatment, they can prevent teeth from relapsing while the final restorations are being fabricated.
Another area of concern comes from the temporization of inlay/onlay preparations. With the trend towards less tooth reduction and more conservative prep designs and the advances in polymer glass materials, there is a greater need for adequate inlay/onlay temporization (figure 4). Most of the same principles that apply to veneer provisionals will also apply here. After the teeth are prepped and the impression done, an adequate temporary will prevent the drifting or over-eruption of teeth, which leads to heavy mesial and distal contacts and/or high bites. Both of these will result in the clinician having to make undesirable adjustments to the restorations.
The use of an antibacterial agent with fluoride can be used to clean the preps. Once again a bonding agent is applied, and again, it is advisable to use an older generation bonding agent, as the newer ones may contain primer. The same procedure can be applied when making larger inlays that fill pulp chambers (figure 5). It is advisable to fill any canals with cotton before the bond material is applied to prevent your bonding agent or temporary material from filling and blocking the canals.
The choice of temporary cement if required is also important. Zinc oxide eugenol cements may leave behind residual eugenol on the tooth surface after removal. The eugenol will interfere with cementation and also soften any resin present in the cement. Non-eugenol temporary cements are best and ones with low bond strength are advisable to facilitate easy removal of the temporary restoration.
With this article, it was my intention to provide you with more options when it comes to the temporization of today's more advanced yet less invasive restorations.
I would like to gratefully acknowledge the help and guidance I received in writing this article from my colleges, Dr. Stephen Abrams of Scarborough and Dr. Joe Bulger of Etobicoke.
Ron Klausz, R.D.T. is owner of Klausz Dental Laboratories, located in North York, Ontario. A second generation registered dental technologist, he has chosen to follow in his father's footsteps. He keeps with the family traditions of producing advanced, high quality restorations while developing unique client and patient care services. He has modernized a company, whose focus is still based on fulfilling client needs. "Working harder and smarter for your practice!" is their credo.
i Abrams, S. H., A Technique for Temporization of Teeth during the Fabrication of Porcelain Veneers. Oral Health, 1996, November, pages 11 - 16
|
|
|
|
|
 |
| 1) Typical labial veneer preperation. |
 |
| 2) Spot etching a 3mm diameter. |
 |
| 3) A resin stent in place. |
 |
| 4) Typical onlay preparation. |
 |
| 5) Inlay preparation into the pulp chamber. |
|
|
