Class II restoration with thermo-viscous composite

Dr Yassine Harichane

Mon. 30. March 2026

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In an earlier article on this topic,¹ I demonstrated the workability of thermo-viscous composites. After warming, the composite can be easily handled for sufficiently long by the practitioner. It is even possible to apply an occlusal stamp to reproduce the preoperative anatomy if it is not compromised. In this article, I will highlight another aspect of the workability of thermo-viscous composites in an everyday but challenging clinical situation: the proximal restoration.

Treatment

The clinical case described in this article concerns a Class II cavity in a premolar (tooth #45) restored using a thermo-viscous composite (Fig. 1). The tooth was isolated with a dental dam (Fig. 2). The cavity was then cleaned (Fig. 3). In order to obtain an anatomically correct distal wall, a matrix, a wedge and a ring were placed (Fig. 4). The tooth enamel was then etched for 30 seconds and the dentine for 15 seconds (DeTrey Conditioner 36, Dentsply Sirona; Fig. 5) and then rinsed and dried thoroughly (Fig. 6). Owing to the thinness of the remaining dentine, pulp protection (Telio Desensitizer, Ivoclar) was also applied (Fig. 7).

Fig. 2: Application of the dental dam.

Fig. 3: Cavity after excavation.

Fig. 4: Placement of the proximal matrix.

Fig. 5: Etching of the enamel and dentine.

Fig. 6: Cavity after rinsing and drying.

Fig. 7: Cavity after use of Telio Desensitizer.

The adhesive (Futurabond DC, VOCO) was applied to the cavity for 20 seconds, then dried for 5 seconds under an oil-free air spray and finally light-polymerised for 10 seconds (Figs. 8 & 9). For optimal wetting, the cavity floor was lined with an extremely thin flowable composite (GrandioSO Light Flow, Shade A3.5; VOCO) and polymerised in 20 seconds (Figs. 10 & 11). Using the VisCalor Dispenser (VOCO), a handheld dispenser that allows simultaneous heating and application of composite, the cavity was then filled with a thermo-viscous bulk-fill composite (VisCalor bulk, Shade A2). The use of a bulk-fill composite allows for rapid filling in a single step, and it can be applied in layers of up to 4 mm. As the composite cools, its viscosity increases, making it very easy to model to recreate the anatomy and remove excess material (Fig. 12). It is even possible to create realistic grooves using a simple endodontic file (Fig. 13).

Fig. 8: Cavity after application of Futurabond DC.

Fig. 9: Light polymerisation of the adhesive.

Fig. 10: Base of the cavity filled with GrandioSO Light Flow.

Fig. 11: Light polymerisation of GrandioSO Light Flow.

Fig. 12: Application of VisCalor bulk.

Fig. 13: Grooves created.

Finally, light polymerisation was performed for 20 seconds (power ≥ 1,000 mW/cm²; Fig. 14). Staining was then done with a light-polymerising tinted composite (FinalTouch, orange; VOCO; Fig. 15). After 20 seconds of polymerisation of the characterisation material (Fig. 16), a glycerine gel was applied (Fig. 17) and then the final light polymerisation was carried out (Fig. 18). The excess was then removed and the surface polished (Fig. 19). To adjust the occlusion, articulating paper was used to visualise the contact points (Fig. 20) and make the necessary corrections (Fig. 21). The final result was very natural (Fig. 22).

Fig. 14: Light polymerisation of VisCalor bulk.

Fig. 15: Application of FinalTouch.

Fig. 16: Light polymerisation of the characterisation material.

Fig. 17: Isolation of the restoration with glycerine.

Fig. 18: Light polymerisation through the glycerine.

Fig. 19: Removal of the proximal matrix.

Fig. 20: Occlusion check before adjustments.

Fig. 21: Occlusion check after adjustments.

Fig. 22: Completed restoration after polishing.

Comparison of the preoperative and postoperative radiographs demonstrates the quality of the treatment (Fig. 23). Owing to the excellent application properties of the thermo-viscous composite, the restoration does not contain any air bubbles. In addition, there is uniformity between the two composites used in terms of visibility on radiographs, and overall, the restoration appears homogeneous, there being no visible transitions between the base flowable composite and the bulk-fill composite. The preoperative radiograph did not show the full extent of the lesion. Only during the treatment did it become apparent that very thorough preparation had to be carried out in order to completely remove the affected tooth structure. In order to maintain the vitality of the pulp, desensitisation was carried out before the actual composite restoration.

Figs. 23a & b: Pre- and post-op radiograph.

Discussion

At the end of the nineteenth century, G.V. Black defined cavity Classes I–V for the categorisation of carious lesions. A sixth class, Class VI, was defined by Simon in 1956.² Class II, the class of the clinical case presented here, refers to caries affecting the proximal surfaces of molars and premolars.

For the practitioner, the challenge lies in respecting the tooth’s natural anatomy and ensuring proper proximal contact points. If anatomical form is lacking, the aesthetics of the restoration will be compromised. Worse still, an inadequate contact point may lead to food impaction, causing discomfort, gingival inflammation and even caries. However, if the dentist succeeds in creating a satisfactory overall anatomical shape, the patient is more likely to retain the tooth in the long term.

To achieve satisfactory anatomy and function, several elements must be considered: preparation, interdental separation and contouring. A matrix should be used to replicate the proximal wall destroyed by the carious lesion. Typically, a metallic matrix is used because it is malleable and does not adhere to the restorative material. The height of the matrix is crucial because, if it is too short, the seal will be compromised, and if it is too long, manipulation will be hampered by the gingival papilla. Interdental separation involves widening the interdental space using a wedge. Usually, the wedge is made of wood or plastic of various sizes. The size of the wedge is crucial because, if the wedge is too small, the contact point will be too loose, but if the wedge is too large, postoperative discomfort may occur. Contouring involves defining the general shape of the proximal surface of the tooth. A ring is typically used to press the matrix against the tooth and give the restoration a natural shape.

While all these steps are technical and time-consuming, they are essential for achieving a satisfactory Class II restoration. Fortunately for practitioners, the actual cavity filling can be quick and convenient. The use of a bulk-fill composite allows for single-step filling if the cavity depth does not exceed 4 mm. In addition, an initial layer may be applied to raise the cavity floor if needed.

By using a thermo-viscous composite, the dentist can fully express the material’s aesthetic potential. It allows for an impressive level of anatomical detail using simple and readily available instruments. First, a probe can be used to carefully remove excess material and shape the general contours of the cusps. It is then possible to create pronounced intercuspal grooves and even define the cusp lobes using an endodontic file. These steps are straightforward and quick and result in a natural-looking restoration.

Conclusion

Proper Class II restoration requires restoration of the aesthetics and, above all, the function of the tooth affected by the carious lesion. The use of a thermo-viscous composite allows for establishing of a satisfactory contact point for the patient within a reasonable working time.

The patient was very satisfied with the treatment results and impressed by the aesthetics of the restoration, which was barely distinguishable from the natural tooth. Furthermore, she was able to floss without any difficulty.

Acknowledgements
I would like to thank Dr Matthias Mehring, VOCO’s knowledge manager, for the contribution of materials.

Editorial note:

References

Harichane Y. Class I restoration with thermo-viscous composite. Cosmet Dent Facial Aesthet Int. 2025;19(1):30–33.
Simon WJ. Clinical operative dentistry. Philadelphia (PA): Saunders; 1956. 381 p.

This article was published in cosmetic dentistry—Magazin für innovative Zahnmedizin Vol. 21, Issue 2/2023. A translated and edited version is provided here with permission. The article also appared in cosmetic dentistry & facial aesthetics international Vol. 19, Issue 2/ 2025.