The variety makes the choice more difficult and in practice learning about the full range familiar is impossible. Bulk-Fill technique, a solution for concurrent applications of large portions of the composite which was introduced a few years ago, carries a lot of risks arising from attempts to overcome the primary disadvantages of materials undergoing light-induced polymerization in a direct application. Obtaining the maximum relaxation of shrinkage stresses accompanying the conversion of a mixture of monomers into polymerized material of satisfactory crosslinking space is just one of the problems. Another problem is to obtain such composition which contains a perfectly balanced proportion of photoinitiator, accelerators in conjunction with colour and a degree of material transparency. On one hand, the material must maintain stability and not be subject to premature polymerization and, on the other hand, it is necessary to ensure the proper reaction in hard-to-reach places for reaction-initiating light. The consequence for many materials of this group is excessive transparency which ensures the penetration of lamp light but at the same time it does not provide for a natural tooth tissue degree of opacity. Excessively „transparent” fills give the impression of grey and thus negates the effort of aesthetic reconstruction.
POLECAMY
The problem of controlling the polymerization initiation onset and ensuring its proper course is solved in the case of structural materials (core build up) and cement through the use of dual methods of initiation, the so-called light-chemo (Dual cure).
On the one hand, the effect ensures proper chemically-initiated polymerization to the bottom of deep cavities, and on the other hand, the reaction acceleration by photo-initiator excitation. Unfortunately, the course of a chemical reaction is determined and the delay it is not possible, but usually working time for these materials is entirely satisfactory.
New aspect – what it is
It is time to go into the details.
Fill-Up! (Fig. 1), new material offered by COLTENE, which uses a two-pronged method of initiating polymerization reaction is the new aspect of Bulk-Fill technique. This material is intended for filling with the use of method of class I and II simultaneous application method, extensive restorations and reconstructions. In addition, it proves useful as material with a possibility for cementing standard inlays at the same time. It is supplied by the manufacturer in two types of kits enclosed with different bonding systems. It is either ParaBond, a two-bottle system, or ONE COAT 7 UNIVERSAL with One Coat 7.0 Activator (Fig. 2 and 3). The possibility of using a system that combines chemically polymerizing frees us from the limitations in the availability of light and thus ensures proper adhesion even in a very deep cavity with missing enamel and dentine substance.
The sets supplied by the manufacturer contain all required components including applicators, automix tips in two diameters (Fig. 4) and bases with light-protecting casing required for the preparation of the blending system.
In practice one can begin work after opening the set. There are two alternative blending systems available and the simple „pictographic” manual significantly minimizes the risk of error in their application. Just one glimpse replaces the cumbersome reading, and in times when we use a lot of preparations, such facilitation improves work comfort.
As they say „a small thing can bring a lot of joy” (Fig. 5 and 6). After using the blending system one proceeds to the application of material using the preferred version of mixing tips.
Application simplicity
The application is surprisingly easy as a result of rather flowable materials. Low surface tension combined with the properties of bonding systems facilitate „flowing” of material in the nooks and hard-to-reach places. But on the other hand, the result of these properties is the lack of thixotropic effect, which in practice means no possibility for modelling the surface morphology. COLTENE suggests two ways to compensate for this: one, to apply a top layer with conventional composite or two, to shape the morphology with rotary instruments after curing. In the author’s opinion and in the light of the proven performance of Fill-Up! it is possible to use this material „alone” with the fact that it will be necessary to model with the use of „lost material method”. This technique is well known and well mastered by many clinicians, and it is still „foundation” of preclinical education. At this point it should be emphasized one more feature of this material namely low transparency and the availability of only one colour – Universal.
The manufacturer declares that the shade is between an A2 and A3 shade but in the author’s opinion and in connection with the said low transparency subjective perception points to A2 or even slightly less brighter. It would be advisable to offer darker colours which will greatly increase the possibility of independent use of this material in the technique of concurrent applications. But in order to consider all values, it should be taken into account that these opaque features significantly facilitate the aesthetics work when the top is covered with light-cured aesthetic composite material. As indicated by the author, the goal is to cover up discolorations and to avoid light curing into depth to limit shrinkage stress. An important aspect to the shade: The shade is initially right after placement rather bright – approximately an A1 – but the material gets slightly darker over the first days and reaches its final appearance only after one week – approximately between A2 and A3.
Depending on preferences and a procedure type polymerization reaction can be initiated with light or wait for its „independent” course. It needs to be remembered that in hard-to-reach places only a chemical reaction is possible, which requires the observance of time specified by the manufacturer.
Attempts to model material during „coagulation” is not a good solution because it will cause abnormal polymerization, defects or significant deterioration of polymer homogeneity.
After bonding the material is rather resistant to model what can be considered as an indication of high wear resistance. But polishing the already modelled area does not pose any difficulty.
Despite the contrast of colour in many cases, the filling border has been seen as tight and free from defects. Fast application and the ability to accelerate polymerization by light-curing significantly reduce the execution time when filling with Bulk-Fill technique. When the manufacturer accedes to a reasonable idea of introducing the material in a wider range of colours, in the author’s opinion the material may become essential in the work of many general dental practices as it respects working time and ensures a sustainable and effective lack of quality defects.
Clinical cases
Case 1
The patient reported for a check-up visit during which an extensive fill in tooth 36 was noticeable. A radiographic test confirmed the correctness of an endodontic treatment conducted earlier in another dental practice. Despite the lack of apparent gaps it was suggested to replace the fill. After a short preparation conducted along the edge of the material the entire composite material was removed to expose the cavity inside and the material filling the pulp chamber. After a necessary preparation a s ingle-layer of the material was applied and subjected to light-induced polymerization. After the matrix was removed during the preparation the surface was modelled by adapting it to the occlusion conditions. The surfaces were polished and the resulting effect was welcomed by the patient. The length of time to do all the work – just over a quarter of an hour – was surprising to the author.
Case 2
MOD-class filling was qualified to be replaced during the preparation and a bigger range had to be made which resulted in the execution of „onlay”. As it is shown in the photo the fill is very clearly distinct from the colour of natural tissues but in tooth 26 it was not a problem for the patient. Also in this case, the great majority of the morphological elements of the occlusal surface were reconstructed by the lost material method and it seems that the correct effect ensures the tooth function restoration.
Foundations are the most important
Bonding systems offered by COLTENE for a long time have been one of the foundations of proving a constantly high quality of these products. It may be mentioned here again that the experience of working with materials of the company, such as Brilliant and SYNERGY D6 represent, in the author’s opinion, standard solutions and permanently fit into standard clinical practice. The whole system of ParaPost® kits which has been evolving and undergoing improvements and adaptations is still one of the very important elements of dental practice. In accordance with the principle of using components from a single manufacturer listed above in connection with new Fill-Up! provides the ability to solve even the most complex situations which we encounter in everyday clinical practice.
