Zygintas Jonaitis

Clinical case by Dr. Zygintas Jonaitis

MINIMALLY INVASIVE INDIRECT RESTORATION PROCEDURE IN THE POSTERIOR REGION

The aim of preserving as much natural tooth structure as possible is ever-present in modern restorative concepts. No matter whether a direct or indirect restorative procedure is preferred, a whole array of tools, techniques and materials are available that help make the clinician's life easier and treatment outcomes more predictable and durable. Those solutions are designed to facilitate identification of tooth structure that needs to be removed, aid cavity cleansing or maximise the bonding performance without adding complexity to the treatment. Using the following clinical example, a possible restorative workflow is described.

RESTORATION REPLACEMENT REQUIRED

This patient presented with a composite restoration on a first molar that attracted our attention. The very extensive composite restoration was worn, lacked good anatomical form and proper occlusal contacts, showed leakage and signs of secondary caries (Fig. 1). The tooth reacted to sweets and cold. It was clear that repair was not the best option: the restoration needed to be replaced. Due to the size of the existing composite filling, it was decided to place an indirect partial restoration that would allow us to save as much natural tooth structure as possible while providing for long clinical service life.

Fig. 1. Initial clinical situation.

SELECTIVE CARIES REMOVAL

After rubber dam placement, the existing restoration was removed carefully, revealing secondary caries underneath the composite (Figs. 2 and 3). To facilitate selective caries removal down to remineralisable (non-infected) dentin, Caries Detector was applied (Fig. 4). This liquid stains only the infected tissue, so that it is easily identified and selectively removed using diamond instruments (Fig. 5). This helps users preserve remineralisable (affected) dentin that may be left untouched and – whenever well-sealed – does not pose a risk for the future restoration.

Fig. 2. Isolation of the working field with rubber dam.

Fig. 3. Removal of the old composite restoration.

Fig. 4. Application of Caries Detector to visualise infected dentin.

Fig. 5. Cavity after the removal of infected dentin.

ADHESIVE PROCEDURE AND BIO-BASE CREATION

To create a stable basis for the indirect restoration, the tooth surface was first cleaned thoroughly using KATANA™ Cleaner (Fig. 6). This cleaning agent developed for intra- and extra-oral use effectively removes contaminants that might compromise adhesion from the surface – a decisive step as a strong and durable bond is the creation of a stable foundation. Subsequently, CLEARFIL™ SE Protect, a self-etching adhesive with MDPB, an antibacterial monomer was applied according to the manufacturer's instructions for use (Fig. 7). Next, a layer of poly ethylene fiber, wettened with CLEARFIL SE Protect Bond was placed and covered with flowable composite (CLEARFIL MAJESTY™ ES Flow Universal). Hereafter a layer of fiber reinforced flowable composite was placed and cured. An impression was taken with an intra-oral scanner and a glass-ceramic restoration produced in the laboratory.

Fig. 6. Cleaning of the tooth structure with KATANA Cleaner.

Fig. 7. Self-etch adhesive with anti bacterial effect applied to the tooth structure.

Fig. 8. Foundation created with fibres, bond and flowable composite.

Fig. 9. Completed with a layer consisting of short-fibre reinforced composite.

TOOTH PREPARATION AND ADHESIVE CEMENTATION

Tooth preparation was performed (Fig. 10). followed by pre-treatment of all surfaces to provide for a strong and durable connection between the foundation and the indirect restoration. The bonding surface of the glass ceramic restoration was etched with hydrofluoric acid before applying a ceramic primer (CLEARFIL™ Ceramic Primer Plus) . Followed by applying PANAVIA™ V5 Paste onto the restoration (Fig. 12). The tooth structure and foundation were treated according to the manufacturers instructions with the system-specific PANAVIA V5 Tooth Primer before placing the restoration. The cement was light-cured thoroughly, restoration margins were cleaned and polished (Fig. 13) and the rubber dam was removed. Figures 14 and 15 show the treatment outcome.

Fig. 10. Prepared tooth prior to adhesive cementation.

Fig. 11. Pre-treatment of the bonding surface of the restoration with a ceramic primer.

Fig. 12. Application of the selected adhesive resin cement onto the restoration.

Fig. 13. Restoration in place.

Fig. 14. Occlusal view of the final restoration.

Fig. 15. Occlusal view of the final restoration

CONCLUSION

The described procedure shows the restoration of a posterior tooth's anatomy and occlusal contacts in cases with severe loss of sound tooth structure. The remaining tissue is preserved wherever possible, while the protective foundation provides for a tight seal of the underlying tooth structure. Utilizing the indirect restoration method supports the restoration's marginal integrity. A long clinical service life may be expected.