Replacement of Amalgam Filings with Composite Resin Restorations:

Composite resin formulations are used with increasing frequency to restore the dentition of optimal health and function.  Due to their inherent aesthetic appearance, composite materials provide clinicians with a predictable and conservative treatment alternative to traditional amalgam restorations.

During the  past several decades, the use of composite resins for the direct restoration of anterior and posterior teeth has significantly increased.  This has been attributed in part to the growing aesthetic  expectations of patients as well as the evolving requisites of clinicians themselves.  These professionals have hel0ped sour the development of amalgam alternatives (i.e. composite resins) capable of satisfying aesthetics bio compatibility, and functional imperatives.  This article demonstrates the use of direct resin restorations for the aesthetic replacement of worn amalgam fillings.

Since their inception, composite resin materials have been regarded as technique-sensitive.  This is perhaps more valid in describing direct treatment of the posterior region, where visibility may be compromised, access may be difficult to achieve, and moisture control can be a concern.  Recent advances in adhesive materials and techniques, however, have considerable eased the preparation and placement of composite resin in this region.  Composite materials with enhanced optical and mechanical properties enable the long term restoration of posterior dentition.  The "pack able" composite materials combine these advantages with long standing placement techniques used for traditional amalgam fillings, which can be a considerable benefit for clinicians.  For successful preparation, it is now only necessary to remove the diseased structure of deficient filling and render a cavity design that will permit adhesive restoration.  Due to these innovations. the preservation of sound tooth structure a principal advantage for conservative treatment is now possible.

Case Presentation
A 27 year old male patient presented for aesthetic replacement of two amalgam filling on teeth #20 and #21. Upon review of the patient's dental history, it was determined that cavities in the premolars has been treated 15 years previously with amalgam fillings.  Clinical diagnosis revealed ditching at the margins and recurrent decay.  Following shade selection and discussion with the patient a treatment plan was developed.  According to this plan the existing fillings would be removed, the cavities would be conservatively prepared and direct composite resin would be used to restore the premolar teeth.  Once the patient provided informed consent, the treatment was initiated.

Surface Conditioning
The completed cavity preparation was scrubbed with a disinfectant: its conservative final design featured divergent cavity walls, rounded line angles and preserved the proximal walls when possible.  Once the teeth were prepared, the "total-etch" procedure was used to establish proper bond strength between the composite resin and the natural tooth structure (i.e., enamel and dentin). Initially the enamel layer was etched with a phosphoric acid get for 15 seconds.  The dentin layer was etched for an additional 10 seconds with the phosphoric gel, which was subsequently rinsed off with water for 5 seconds.  Excess water was removed from the preparations with a cotton pellet.  
     In order to conditional the teeth for the composite resin restorations, a single component, fifth generation adhesive agent was applied over the prepared cavity sites and gently agitated for 20 seconds.  The ensured maximum penetration of the adhesive into the dentin tubules and allowed a high bond strength to be achieved.  Any excess adhesive was removed with a dry disposable brush, and the solvent was evaporated with a contamination free air dryer for 5 seconds.  the adhesive was polymerized with a halogen light for 10 seconds.

Incremental Composite Buildup
The  initial layer of the direct restoration was restored with A2 shaded Flow Line, which was placed in the floor of the prepared cavity of teeth #20 an #21.  This 0.5 mm layer of flow able composite resin would ensure intimate adaptation to the cavity and potentially address polymerization shrinkage issues.  Once the flow able composite had been polymerized, Solitaire 2 was selected for the next increment of the direct buildup and carefully shaped to the walls of the preparations.  Since it would not adhere to dental instruments or collapse after shaping the pack able composite provided a suitable alternative for use in the patient's posterior region, where replication of natural morphology would be necessary.  In order to provide an more natural, aesthetic appearance for the restorations, an ochre tint was applied to the pits an fissures of the teeth.  Placed over the initial composite layer prior to polymerization, this effect would ensure proper color match with the adjacent teeth.
     Once the second layer of composite has been properly light cured with a halogen light a final increment of composite resin was applied.  This occlusal layer was packed into the premolar preparations to create proper morphology.  The incremental composite layering technique was used to minimize the potential of polymerization shrinkage, which could have resulted in postoperative sensitivity.  The composite materials were light cured for 20 seconds per layer, and the retaining clamp was remove.

Finishing and Polishing
Upon completion of the composite resin buildup, minimal finishing with carbide burs was performed due to the precise replication of natural tooth morphology.  The rubber dam was then removed, and occlusal contacts were evaluated through the use of articulation paper.  The definitive premolar restorations were polished with silicone point and diamond pastes to render a natural luster for the teeth.  At this time the direct restoration were evaluated for aesthetics and integration with the adjacent teeth.

Conclusion
Contemporary composite resins allows clinicians to provide and aesthetic means of restoring their patients to proper health and function.  Since Solitaire 2 can be effectively packed into treatment site by the same techniques clinicians use for amalgam fillings, it thus represents an ideal alternative to these conventional materials.  The handling and optical characteristics of the composite resin enable direct restoration to be predictable performed and harmoniously integrated with the natural dentition.  As the number of patients requesting aesthetic enhancement continues to grow. composite materials such a Solitaire 2 will undoubtedly assume a great role in the restorative practice