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The next issue I would like to discuss is whether or not it is advisable to progressively load implant supported restorations with linear implant configurations with provisional restorations fabricated out of acrylic resin. I believe there is no scientific justification for this practice and I would like to explain why. |
| Here are the results of a finite element analysis study which compared the stress distribution characteristics of different types of occlusal materials. The study was conducted by Dr. Cho at Dan Kook University in South Korea . Both materials were exposed to the same occlusal load. The restoration on the left is restored with acrylic resin, and the one on the right is restored with a gold alloy. Note that the stress distribution patterns resulting in the underlying bone are identical. Any possible dampening effect that is provided by acrylic resin provisional restorations is disproven by the results of this study. So we only use provisionals for the purpose of designing the definitive restoration. We don't use provisionals to progressively load the implant because we believe that regardless of the type of material used for the occlusal surface of the restoration the forces that are ultimately delivered to the bone are unchanged. If an implant is going to fail it is because it lacks adequate bone anchorage to support the occlusal load. This is particularly true in the posterior maxilla. |   |
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Here in this patient we have used a provisional restoration to determine the type of restoration - fixed or removable - that best suits the patient; |
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Based on the results of the use of the provisional we felt we could achieve our goals and those of the patient with a fixed bridge as seen here. |
In this patient, issues regarding the smile line, and esthetics, were resolved by use of a provisional restoration. So, at UCLA we use provisional restorations of acrylic resin to help us design the definitive prosthesis - not to progressively load the implants in the hope of improving the bone implant interface.
