Salvatore Scolavino

Case by Dr. Salvatore Scolavino

After decades of developing and improving the matrix chemistry and filler technology contained in resinbased composites, the products available for direct restorative procedures finally seemed technically mature. What remained challenging, however, was the management of the extremely wide range of tooth shades and opacities available for each product: The dentin, body and enamel masses had to be selected and combined in the right way to obtain a perfect colour match and optical integration with the surrounding tooth structure. The difficulties associated with shade selection and calibration of layer thicknesses (particularly the top enamel layer) required to obtain the desired optical (desaturation) effects have now also finally been overcome.

The reason is that further improvements of the composites’ optical properties, mainly achieved through a careful selection and combination of fillers, have enabled the production of materials with optimized light diffusion properties. These properties enable the restorations to blend in smoothly with the adjacent tooth structure, thus paving the way for a single-shade concept (SSC). This concept involves the use of a single mass of composite to restore the function and aesthetics compromised by the loss of dental structure.

This translates into a significant saving of chair time and a high predictability of aesthetic outcome. A composite material supporting a single-shade technique needs to have medium opacity and a technology ensuring that the incoming light is absorbed, reflected and scattered in the right way to merge effortlessly with the surrounding natural dentition and create a biomimetic effect. The following clinical case reveals how the Light Diffusion Technology used in the CLEARFIL MAJESTY™ ES-2 Universal composite system (Kuraray Noritake Dental Inc.) leads to a highly predictable aesthetic integration obtained using the SSC.

Case description

The 30-year-old female patient presented for a check-up, during which it appeared that her composite restorations in the second quadrant (the maxillary left first and second molar) needed to be replaced due to marginal leakage (Fig. 1). Once the rubber dam was in place (Fig. 2), the existing composite restorations were removed using a round multi-blade bur, which allowing for a selective removal of composite and carious tissue. The extension of the cavity was performed with a truncated cone diamond bur (fine). Once the cavity preparation was completed (Fig. 3), the enamel and dentin surfaces were cleaned by sandblasting with aluminium oxide (50 μm). Selective etching of the enamel was performed with K-ETCHANT Syringe (Kuraray Noritake Dental; Fig. 4), followed by thorough rinsing and drying of the tooth (Fig. 5). For the adhesive procedure with CLEARFIL™ SE BOND 2 (Kuraray Noritake Dental), the primer was applied first (Fig. 6), rubbed into the tooth surface for 40 seconds and air-dried. The bond was subsequently applied in the same manner (Fig. 7). After several seconds of air flowing to create homogeneous surface the adhesive was light-cured for 40 seconds (Fig. 8). As the last phase of the adhesive procedure, a 1-mm-thick layer of flowable composite (CLEARFIL MAJESTY™ ES-Flow Super Low A3, Kuraray Noritake Dental) was applied to cover the adhesive on the dentin (Figs. 9 and 10).

Fig. 1. Pre-operative clinical image.

Fig. 2. Isolation with rubber dam.

Fig. 3. First and second molar after cavity preparation.

Fig. 4. Selective etching of the enamel.

Fig. 5. Cavities ready for the adhesive procedure.

Fig. 6. Application of the tooth primer.

Fig. 7. Glossy appearance of the cavities after application of the bond.

Fig. 8. Light-curing of the adhesive layer.

Fig. 9. Application of flowable composite.

Fig. 10. Cusp-by-cusp modelling of the universal composite.

In the modelling phase, the posterior shade U of the composite CLEARFIL MAJESTY™ ES-2 Universal was placed using the cusp-by-cusp technique (Figs. 11 and 12). In order to improve the optical integration of the restorations, some brown stain (CHROMA ZONE™ COLOR STAIN Dark Brown, Kuraray Noritake Dental) was added to the fissures (Fig. 13). For finishing, we used a multi-blade ball-shaped bur and an Arkansas Flame abrasive stone (Fig. 14). Polishing of the restorations was accomplished with the TWIST™ DIA system (EVE; Fig. 15). After rubber dam removal, the occlusal check was performed with articulating paper (Fig. 16), minimal adjustments were made and the surfaces repolished. The integration of the restorations after 30 days fully meets the clinical expectations (Figs. 17 to 20).

Fig. 11. Glossy appearance of the cavities after application of the bond.

Fig. 12. Completed occlusal anatomy.

Fig. 13. Stained fissures.

Fig. 14. Matte surfaces after finishing.

Fig. 15. High-gloss surfaces after polishing.

FINAL SITUATION

Fig. 16. Whole quadrant after rubber dam removal and the occlusal check.

Fig. 17. Whole quadrant at the 1-month-recall.

Fig. 18. Occlusal view of the restorations …

Fig. 19. … after one month.

Conclusion

The innovative composite system CLEARFIL MAJESTY™ ES-2 Universal, which consists of two shades for the anterior and a single shade option for the posterior region, offers the properties needed for a successful implementation of the single shade technique. Used in the posterior region, the material is sufficiently opaque to mask optical irregularities of the underlying tooth structure, while it is translucent enough to provide for an imperceptible optical transition from the tooth structure to the restoration. Irrespective of the tooth shade, the restoration merges smoothly with the surrounding natural dentition, creating a harmonic overall picture.

Case by Dr. Salvatore Scolavino

The establishing of a stable occlusal relationship is one of the biggest challenges dental practitioners are facing when restoring posterior teeth with resin composite, but it is a task with a decisive impact on the integrity of the masticatory apparatus. A poor static and dynamic occlusion may have a negative effect on the restored tooth, the periodontal apparatus, and also on the opposing dentition.¹ Ideally, the occlusal anatomy of direct restorations is designed in a way that occlusal forces are directed along the long axis of the tooth, which is achieved when each cusp tip in occlusal contact touches a flat surface. Horizontally directed forces, on the other hand, should be avoided, as they tend to cause tipping and increase the risk of cuspal fracture, tooth mobility etc.

In cases concerning improper occlusal relationship involving tipping of restored teeth, it may be possible to stabilize the situation by replacing the restoration and re-establishing a proper occlusion. If carried out correctly and early enough, this restorative approach may be a way around orthodontic treatment. The following clinical case is used to demonstrate how to create a functional occlusal surface right away – without larger adjustments. The whole restorative procedure is simplified by the use of a universal composite with a single posterior shade that eliminates the need for shade determination and shade selection, while it produces lifelike treatment outcomes.

Case description

This patient presented with direct composite restorations in the mandibular left first and second molar that were lacking an elaborated occlusal morphology (Fig. 1). The second molar appeared to be tipped mesially towards the first molar (Figs. 2 and 3), which resulted in improper occlusal relationships and a decreased position of the mesial marginal ridge. In order to verify the clinical and radiographic observation of an improper occlusal relationship, the occlusal contacts were recorded with articulating paper (Fig. 4). As expected, there was an uneven distribution of occlusal contacts, which were exclusively located in the distobuccal area on the second molar, and not matching the tooth-restoration interface on both molars.

Fig. 1. Pre-operative clinical situation: Occlusal view.

Fig. 2. Pre-operative clinical situation: Lateral view revealing the tipping of the second molar.

Fig. 3. Pre-operative bite-wing radiograph confirming the tipping issue.

Fig. 4. Checking of the occlusal contacts.

Planned approach

As orthodontic treatment was not an option, it was decided to replace the composite restorations, thereby treating the Class I cavity of the second molar as if it were a Class II cavity. This would allow us to increase the height of the mesial marginal ridge and establish the proper occlusion.

Preliminary measures

Once the rubber dam was placed (Fig. 5), the existing composite restorations were removed and the cavity slightly extended with a diamond chamfer bur (Fig. 6). The result of this procedure is shown in Figure 7. In order to provide an anatomical build-up of the mesial wall, a sectional matrix was mounted with the aid of a wooden wedge and a separator ring (Fig. 8).

Fig. 5. Isolation with rubber dam, held in place with a clamp and a wedge.

Fig. 6. Tooth preparation with a diamond chamfer bur.

Fig. 7. Appearance of the teeth after preparation.

Fig. 8. Sectional matrix, wedge and separator ring in place.

Adhesive procedure

After selective etching of the enamel (K-ETCHANT GEL, Kuraray Noritake Dental Inc.) (Fig. 9), the enamel bonding surfaces had a chalky-white appearance, which indicates properties that are favourable for bonding (Fig. 10). The adhesive procedure was performed with CLEARFIL™ SE BOND 2 (Kuraray Noritake Dental; Fig. 11). In the first step, the primer of the system was applied and actively rubbed into the surface for 40 seconds, and air-dried. Subsequently, the bond was used in the same manner. After complete evaporation of the solvent, the bonding surface was light-cured for 40 seconds to ensure proper polymerisation. The cavity floor was then covered with a 1 mm thick layer of flowable composite (CLEARFIL MAJESTY™ ES FLOW SUPER LOW A3, Kuraray Noritake Dental).

Fig. 9. Selective etching of the enamel.

Fig. 10. Chalky-white enamel surfaces.

Fig. 11. Glossy appearance of the bonding surfaces after application of the tooth primer and bond.

Restoration procedure

Before starting to elevate the mesial wall of the second molar using the centripetal build-up technique² (Fig. 12), we analyzed the height of the marginal ridge and anatomical details of the contralateral tooth, while the adjacent molar provided orientation as well. In general, knowledge not only about the tooth’s typical anatomy, but also about the patient-specific anatomical details of the adjacent and contralateral teeth as well as the antagonist is very useful for designing the occlusal anatomy. In addition, remaining anatomical structures should be read and used. In this particular case, the restorations were completed with CLEARFIL MAJESTY™ ES-2 Universal composite (Kuraray Noritake Dental) in the posterior shade U, using the cusp-by-cusp technique (Figs. 13 to 15). In most areas, it was possible to follow the inclination of the remaining cusps and the orientation of the grooves to produce an ideal surface anatomy. For those who would like to speed up the procedure, the simultaneous modeling technique³ may be an option. In this technique, the cusps are built up simultaneously from separate increments, which remain out of contact to each other until light-cured in a single curing cycle.

Fig. 12. Mesial wall built up with composite.

Fig. 13. Application of the first increment for cusp build-up. It is useful to limit the size of the increments for controllability.

Fig. 14. Cusp-by-cusp build-up completed on the second molar.

Fig. 15. Molars with restored occlusal surfaces.

In order to improve the already great optical integration of the restorations, some stain (Dark Brown, CHROMA ZONE™ COLOR STAIN, Kuraray Noritake Dental) was applied to the fissures. A multi-blade ball shaped bur and an Arkansas Flame abrasive stone were used for finishing. Final polishing was accomplished with the TWIST™ DIA system (EVE). The immediate treatment outcome is shown in Figure 16. The patient was released after rubber dam removal, checking the static and dynamic occlusion, and conducting a control radiograph (Fig. 17). The optical integration was even better at the recall after one month due to the rehydration of the surrounding tissues (Fig. 18), while the functional integration was excellent and no occlusal adjustments were required.

Fig. 16. Immediate treatment outcome with a nice optical integration of the restorations providing for a stable occlusal relationship.

Fig. 17. Control radiograph taken after the direct restoration procedure.

FINAL SITUATION

Fig. 18. Treatment outcome at recall after 30 days.

Conclusion

The presented case example reveals how important it is to strive for occlusal stability when restoring posterior teeth with composite. Furthermore, it demonstrates how it is possible to re-establish a stable occlusal relationship, even if some tipping has already occurred. In order to get it right the first time, it is essential to make use of the remaining anatomical structures, which guide the way toward an occlusal surface that ensures a favourable distribution of occlusal forces, and therefore provides optimal conditions for a long life of the freshly restored teeth. The combined use of the presented restorative techniques with innovative materials like CLEARFIL MAJESTY™ ES-2 Universal will make the procedures simpler and even more efficient.

References

1 Sandhu S, Lal J, Singh R, Sandhu R, Sra J. Significance of establishing occlusal anatomy in operative dentistry. Saint Int Dent J 2016;2:7-10.
2 Bichacho N. The centripetal build-up for composite resin posterior restorations. Pract Periodontics Aesthet Dent. 1994 Apr;6(3):17-23.
3 Scolavino S, Paolone G, Orsini G, Devoto W, Putignano A. The Simultaneous Modeling Technique: closing gaps in posteriors. Int J Esthet Dent. 2016 Spring;11(1):58-81.