Teeth that are periodontally compromised with loss of attachment and bone height often have increasing levels of mobility. Recent research supports the use of tooth stabilization and splinting to improve the prognosis.1 There are three primary indications for splinting periodontally involved teeth:
- – primary occlusal trauma;
- – secondary occlusal trauma;
- – progressive mobility, migration or pain on function.2
In recent years, conservative splinting involving the use of continuous, woven-fiber reinforcement has been described and has become a well-accepted technique.3–7
One problem associated with the use of fiber reinforcement with composite resin for directly placed periodontal splints is the composite resin excess that flows into the interproximal gingival spaces. Even using wooden wedges to minimize the excess may not completely solve the problem. In some cases, the gingival spaces of periodontally involved teeth are larger than even the largest wooden wedge. Also, wedges do not completely adapt to the shape of the embrasure space and can lock into the composite resin after polymerization, making it difficult to remove the wedge.
Excess composite resin is difficult to remove from the crown and root surfaces after light-curing. Accomplishing this may require the use of a finishing bur or diamond on a high-speed handpiece, which has the potential to notch the root surface and can be uncomfortable for the patient if the teeth are not anesthetized. One technique that is less hazardous involves the use of a reciprocating handpiece (Profin, Dentatus USA) with thin-bladed lamineer abrasive tips.
We propose a block-out technique to minimize excesses and cleanup of composite resin when placing direct bonded fiber-reinforced composite resin splints. The technique involves the use of an elastomeric impression material placed into the gingival spaces between the teeth below the contact area. It is critical that the teeth be etched before this block-out technique is used.
THE TECHNIQUE
When placing the splint, clinicians need to isolate the field. This can be accomplished with a rubber dam or with the placement of absorbents. After determining the length of reinforcement ribbon needed for the splint and cutting the ribbon to the chosen width and length, the dentist thoroughly cleans the teeth of plaque and stain using pumice with a prophylaxis cup. The interproximal surfaces are cleaned with sandpaper finishing strips or diamond abrasive strips. Any additional tooth preparations are then completed. This can include the placement of a channel on the lingual or facial surface of the teeth.
The teeth are etched with a phosphoric acid etchant for 30 seconds, rinsed with water and dried. The elastomeric impression material is then syringed into the inter-proximal spaces below the proximal contact areas. Although any elastomeric impression material can be used and placed with an impression syringe, we have found that a heavy-bodied automix polysiloxane impression material is the easiest to use. Medium-bodied polyether impression materials also work well. In either case, the impression material will be completely set within four minutes. Whichever impression material is selected, it is important that the teeth be etched and dried before the block-out material is placed to avoid trapping moisture that could contaminate the bonding procedure.
Before placing the impression material between the teeth, clinicians should be careful to keep the material below the proximal contacts to avoid flow into these spaces, which might hamper placement of adhesive and composite resin during the fabrication of the splint. Also, they should verify that the impression material has completely blocked out areas to avoid an excess of composite resin that would have to be removed during curing and finishing. Any misplaced impression material can be removed easily with a scalpel and a No. 12 blade.
In cases in which the area can be kept isolated and dry without the rubber dam, the impression material can be placed as a continuous wash around the teeth and soft tissues. Lip retractors are used to isolate the teeth to be splinted, and the automix polysiloxane impression material is placed into the gingival embrasures and covers the adjacent soft tissues to block out these spaces (Figure 1
). Use of a rubber dam will make the gingival embrasures smaller. In such cases, the impression material is placed in each interproximal gingival embrasure space (Figure 2).
