The use of bulk fill materials appear to provide the advantages of an aesthetic material with less sensitive placement, offering a real alternative to amalgam in posterior restorations

Over recent decades, the demand for more aesthetically pleasing, tooth coloured restorations has led to composite being one of the most commonly used dental materials. With the Minamata Convention 2013 calling for the phase-out of dental amalgam, it is likely that the dental profession’s reliance upon composite for the restoration of posterior teeth will only increase¹.

The placement of posterior composites is not without its limitations. Proper isolation of the tooth is required and an incremental layering technique is currently recommended². Layering composite improves light penetration, allowing for complete polymerisation of the material, and controls polymerisation shrinkage. However, this technique can be time-consuming and can lead to the introduction of voids to the restoration.

In order to simplify and speed up the placement of large posterior composites, a number of bulk-fill composite resins have come on the market, aiming to produce a composite restoration that does not require the multi-layering technique.

Bulk-fill restorative materials can generally be categorised into bulk-fill composites (e.g. Tetric Evoceram, Ivoclar Vivodent) and bulk-fill flowable composite materials (e.g. Venus bulk fill, Smart Dentine Replacement (SDR) and Filtek). The latter often require a conventional layer of composite to cap the restoration due to the reduced wear resistance and hardness properties ³.

Properties and clinical handling of Fill Up!

Fill Up! is a new dual-cure bulk-fill composite. The manufacturer claims to have produced an aesthetic, single-step composite material that is suitable for class I and II posterior restorations⁴.

The majority of bulk-fill composites on the market are light-cured. Manufacturers have attempted to increase the depth of cure, by either increasing the translucency or reducing the filler content of the material. Despite these changes, these materials are still limited to being used in increments of 4-5mm.

In restorations greater than this, there is a significant question if the base of the restoration has been fully polymerised. In addition, the effectiveness of light cure units within general practice has often been found to be inadequate, with up to 50 per cent of units not reaching minimum irradiation levels⁵. Some evidence suggests that the manufacturers’ recommended cure times for bulk-fill composites cannot be endorsed, with longer curing times being required⁶.

In an attempt to overcome this problem, Fill Up! is a dual cure composite. The surface can be light cured, to allow immediate finishing and polishing, while the full depth of the restoration will be chemically cured within three minutes. Fill-up has been shown to be suitable for bulk-filling cavities of up to 10mm in depth.

The placement of Fill Up! is simpler than conventional composites, but slightly more technique sensitive than for amalgam. Proper isolation is important and still required. The flowable nature of the material allows for good adaptability to the cavity walls and the single application of the material reduces the risk of voids and contamination. The material comes in an easy-to-use auto-mix syringe. Dual cure composite restorations have shown to have favourable marginal adaptation when compared with conventional composite placement⁷.

Fill-Up! contains zinc oxide which has proven antibacterial activity against dental pathogens^8,9 without affecting the strength of the material¹⁰.This may aid reducing the risk of secondary caries at the margins of these restorations. Fill Up! is radiopaque, therefore restorations are easy to detect on dental radiographs.

Fill-Up! composite is available in one universal, tooth-coloured shade. Unlike some other bulk composites, an aesthetic surface layer is not necessarily required. Due to the composite being chemically cured, the material darkens within the first 24 hours after initial placement. Due to this and the limited shade options available, this material should ideally not be used in the aesthetically important zone. However, Fill-Up! can still be used as dentine replacement with a capping layer of conventional composite to improve the aesthetics⁴.

The authors have found Fill-Up! to be an excellent material option when providing a definitive coronal restoration post-endodontic treatment, which often suit a flowable material with deep cavities over 4mm. Fill-Up! is good to prep for indirect restorations if used as a core as it is hard like conventional composites, rather than very soft like many GIC’s. The material should be equally adept for routine definitive posterior restorations.

Clinical case one

A patient attended for root treatment of the lower left first premolar. This tooth was subsequently restored using the direct bulk fill composite, Fill-up!, in combination with the Parabond adhesive system. This provided an aesthetically pleasing and conservative restoration.

• Step 1: The cavity was prepared and a sectional matrix band placed (Fig 1).
• Step 2: The cavity was etched for 15 seconds. The etchant was rinsed and air dried according to the manufacturer’s instructions (Fig 2).
• Step 3: The bonding agent Parabond was applied. It was massaged into tooth structure for 30 seconds and then blown with air for 30 seconds (Fig 3).
• Step 4: The tip of the composite dispensing nozzle was placed at the deepest point of the base of the cavity and the cavity filled with the bulk composite (Figs 4 and 5).
• Step 5: The composite material was light cured for 10 seconds. The occlusion was checked and the restoration polished (Fig 6).

Clinical case two

This patient had a biodentine direct pulp cap placed on the upper left first molar 12 months prior to treatment. The tooth responded positively to sensibility testing (ethyl chloride and electric pulp testing) and the pre-operative radiograph showed no associated periapical radiolucency. Fill Up! bulk-fill composite was chosen to provide the definitive restoration.

• Step 1: The tooth was isolated using rubber dam. The Biodentine was removed to leave 1mm at the base of the cavity (Fig 7).
• Step 2: The tooth was etched and bonded as per the manufacturer’s instructions (Figs 8 and 9).
• Step 3: The cavity was filled using Fill Up! bulk-fill composite in a single increment (Figs 10 and 11). The tooth was overfilled before polishing (Fig 12).
• Step 4: The final photograph shows the tooth nine days after placement with minimal darkening of the restoration (Fig 13).

Conclusion

Fill Up! provides an aesthetically pleasing, tooth coloured restoration that is quick and easy for clinicians to place. The material may be particularly useful when restoring cavities in children and anxious patients where the length of treatment time is ideally kept short. Bulk-fill composite restorations are showing early promise within the literature, which is comparable to conventional materials¹¹.

The use of bulk fill materials appears to provide the advantages of an aesthetic material with less technique-sensitive placement, offering a real alternative to amalgam in posterior restorations. However, more clinical research on the long-term outcomes of this material and other bulk-fills is required before its effectiveness can be assessed fully. Early indicators are that it appears to be a useful addition to the dentist’s armamentarium for a variety of clinical applications.

References

1. Lynch C D, Wilson N H F. Managing the phase-down of amalgam: part I. Educational and training issues. British Dental Journal. 215: 109-113.2013

2. Albers H F. Tooth-coloured Restoratives: Principles and Techniques, 9th Ed. BC Decker. 2002.

3. Le Prince J G, Palin W M, Vanacker J, Sabbagh J, Devaux J, Le Loup G. Physico-mechanical characteristics of commercially available bulk-fill composites. J Dent. 42(8):993-1000. 2014

4. Fill-Up. Coltene. Cited 2015 from: http://www.coltene.com/en/products/11/details/2933/Fill-Up!.html

5. Pellisier B, Jacquot B, Palin W M & Shorthall A C. Three generations of LED lights and clinical implications for optimising their use. 1: From past to present. Dent Update. 38:660-670. 2011.

6. Tarle Z, Attin T, Marovic D, Andermatt L, Ristic M, Taubock T T. Influence of irradiation time on subsurface dgree of conversion and microhardness of high-viscosity bulk-fill resin composites. Clin Oral Investig 19(4):831-40. 2014

7. Bortlotto T, Melian K & Krejci I.Effect of dual-cure composite resin as restorative material on marginal adaptation of class 2 restorations. Quintessence Int. 44(9):663-72. 2013.

8. Grenho L, Monteiro F J & Pia Ferraz M. In vitro analysis of the antibacterial effect of nanohydroxyapatite-ZnO composites.J Biomed Mater Res A. 102(10):3726-33. 2014

9. Kasraei S, Sami L, Hendi S, Alikhani M Y, Rezaei-Soufi L & Khamverdi Z. Antibacterial properties of composite resins incorporating silver and zinc oxide nanoparticles on streptococcus mutans and lactobacillus. Resto Dent Endod. 39(2):109-14. 2014

10. Tavassoli Hojati S, Alaghemand H, Hamze F, Ahmadian Babaki F, Rajab-Nia R, Rezvani M B, Kaviani M, Atai M. Dent Mater. 29(5):495-505. 2013

11. Van Dijken, J W & Pallesen, U. Randomized three-year clinical evaluation of class I and II posterior resin restorations placed with a Bulk-Fill resin composite and a one-step self etching adhesive. J Adhes Dent. 17(1):81-8. 2014

About the authors

This article was co-authored by Amy Gallacher, Adam Jowett, James Chesterman and Peter Nixon.

Figures

Fig 1 Cavity prepared

Fig 2 Etchant Gel S applied for 15 seconds and rinsed thoroughly

Fig 3 ParaBond Adhesive was applied to the dry cavity

Fig 4 The Fill Up! dispensing tip was placed into deepest part of cavity

Fig 5 The cavity was restored in a single increment

Fig 6 The light-cured surface was finished immediately

Fig 7 Prepared cavity with remaining Biodentin base

Fig 8 Etchant Gel S applied for 15 seconds and rinsed thoroughly

Fig 9 ParaBond Adhesive applied to the dry cavity

Fig 10 Fill Up! dispensing tip placed into the deepest part of cavity

Fig 11 Cavity restored in a single increment and slightly overfilled

Fig 12 Finished restoration

Fig 13 The final restoration reviewed after nine days