Excellent temporaries User report on Structur 2 SC and Structur 2 Premium from VOCO T he use of acrylic and composite type materials for the provisionalisation of crown and bridge work has been well established over many years and most materials on the market today use a two part catalyst and base system, combined with the now very common auto mix syringe. This has resulted in easy to use, easy to mix products combined with a simple and precise delivery system. To achieve success in crown and bridge work it isessential to create temporaries which fulfill certain criteria such as aesthetics (including tooth form), occlusion, durability and quality of fit. The purpose of this article is to look at how Structur 2 SC and Structur Premium cope with meeting these goals. Currently the most popular way of making provisional restorations (where there is only a relatively small amount of change to be made to the existing structure) is to take a putty, or putty and wash impression, of the existing tooth or restoration. This simple and reliable method allows the formation of a matrix which has enough elasticity to be removed from undercuts and interproximal areas without tearing or distorting, but adequate rigidity to reproduce the original anatomy in considerable detail (see Figure 1). This also has the advantage that it can be kept in the surgery indefinitely, without distorting, until the final restoration is ready. In the unlikely event that the temporary is lost or fractures, a new one can be quickly and easily made. Figure 1: Case 1: Structur 2 SC temporary crown on tooth 46, showing an accurate reproduction of the original crown (which needed to be replaced due to recurrent distal caries). Figure 2: Case 1: Soft tissue at fit stage with optimal soft tissue collar. 32 Figure 3: Case 1: Emergence profile of new crowns. Figure 4: Case 1: Crowns in situ
CLINICALREPORT TECHNOLOGY USERREPORT MATERIALS Figure 6: Case 2: Preoperative view with narrow buccal corridor in the area 13 to 16. Figure 5: Intro-Set Structur 2 SC (Self-curing temporary crown and bridge material in cartridges). One of the most important aspects of successful crown and bridge work is the soft tissue aes-thetic, and the temporary restoration plays an extremely important part in not only maintaining this but, in certain situations, actually helping to develop a new profile (see Figure 2 and 3). If the final crown is to have a natural emergence profile, the gingiva needs to be held in the de-sired position. Failure to do so can, on some occasions, result in recession and loss of aesthetics. Figures 2, 3 and 4 demonstrate how the accuracy of fit of the temporary will allow maintenance of an ideal gingival collar when preparing subgingival margins. This type of result has been very easy to achieve with Structur 2 SC as it is very accurate and has a surface texture which is highly polymerized when set and easy to polish. Having a polished, hard margin helps to minimize the amount of bacteria attracted to the surface while also being easier for the patient to maintain. One of the problems I have encountered over the years is that most of the products available on the market have different quantities of catalyst and base in the syringe delivery system. This means that there can be a slightly uneven mix of the two parts, with the result that there is a slightly uneven polymerization of the material. This leads to two problems. Firstly, that the surface texture can be excessively tacky which can make the temporary inaccurate and hard to polish, and secondly, there can be hidden weaknesses in the material which only become apparent when the temporary restoration has been in the mouth and under loading for a few days. Figure 7: Case 2: With Structur 2 SC temporaries in place on teeth 15, 14 and 13 only. Figure 8: Case 2: Final porcelain veneer restorations on teeth 15, 14, 13 and 12. Figure 9: Case 3: Pre-operative view. 33
Figure 10: Case 3: Diagnostic wax up. Figure 11: Case 3: Temporaries allowing good visualization of wax up, including surface texture detail making assessment of changes far easier. 34 Figure 12: Case 4: Pre-operative view. VOCO has got around this problem by supplying a material which is divided in two identical syringe sizes of catalyst and base ensuring a much more even mix and therefore an even set, significantly reducing these problems (Figure 5). Structur 2 is a flowable self-curing composite with phased polymerisation. This allows for a flexible stage where the material can still be removed from minor undercuts before final hardness has been reached, but without causing marked loss in accuracy of fit. This can be extremely useful when removing multiple units or bridgework. The setting time is conveniently short and allows for final trimming and polishing after just 3 minutes. Alternatively, when there are more extensive changes planned to either the occlusion or the aesthetics, a diagnostic wax up is often a better starting point for the matrix. Again, the ability to accurately reproduce this information in the mouth is essential when assessing any aesthetic or occlusal changes to be made. Structur 2 SC has proved to be very reliable in this respect, as shown below in Figures 6-11. Figure 13: Case 4: Structur 2 SC temporaries with reline of margins to allow ideal gingival contour. One of the most common problems encountered with provisional restorations when preparing subgingivally is that they can have very thin fragile margins. This is usually caused by the fact that once the support provided by the hard tissue of the tooth is removed, the soft tissue can collapse into the space which is to be taken by temporary material. As previously stated, an under-contoured crown lacking in soft tissue support can be the reason for minor tissue irritation and recession, resulting in a loss of aesthetics at or shortly after the final cementation stage. To get around this problem it is often necessary to add to the margins of the temporary restora-tion to create a more ideal result. Having a material such as Structur 2 SC allows for easy adjustment, by simply applying a layer of flowable composite or acrylic, as both materials exhibit an extremely good bond with a near seamless joint. Neither material requires any special bonding technique which saves huge amounts of time, cost and trouble.
THE ALTERNATIVE. Light-curing posterior restorative Alternative: Large restorations without amalgam Quick: 4 mm layers are cured in 10 seconds Universal shade: Provides excellent match to the natural tooth shade through chameleon effect NOW AVAILABLE IN BULK PACK VOCO GmbH P.O. Box 767 27457 Cuxhaven Germany Tel. +49 (4721) 719-0 Fax +49 (4721) 719-140 www.voco.com 35
Figure 14: Case 5: Preoperative view Figure 15: Case 5: Temporary veneers using Structur Premium. A high gloss finish was achieved not only at the fir preparation stage, but also maintained 14 days later at the fit stage of the final veneers. Gross adjustment of Structur 2 SC can be easily achieved using a coarse polishing disk without risk of fracture of even fine knife edge margins. The final polish is then achieved with either a fine disk or a polishing mop to achieve a high luster finish. Figures 14-17 show the temporary veneers using Structur Premium. A high gloss finish was achieved not only at the fit preparation stage but also maintained ten days later at the fit stage of the final veneers. Having worked with Structur 2 SC for several years now I have been extremely impressed by the strength of the material and have experienced very few incidence of fracture, even when constructing bridgework of up to six units in length. Obviously, this is only the case when there has been adequate reduction of the underlying tooth structure and the overall bite has been carefully considered. Lastly in the anterior region where patient are even more conscious of the look of the new tem-poraries, VOCO has introduced in 2005 a more aesthetic temporary material called Structur Premium. This material has a sub-micron filler system which has distinct advantages in the ante-rior region as it can be highly polished, as well as having improved bonding characteristics when using it in situations such as temporary veneers, where a degree of bonding is required to retain the restoration. Overall, I have been extremely impressed with both these products from VOCO, and having tried most of the other materials commonly available, have found it to be the most reliable and cost effective material of this type on the market and would encourage anyone to give it a try. Figure 16: Case 5: Preoperative view ABOUT THE EXPERT James Green, BDS graduated from Newcastle Dental School in 1990 and is an experienced practitioner in the field of aesthetic and restorative dentistry. He is the Principal of a private practice in Oxford, England and a former clinical demonstrator, Department of Restorative Dentistry, Guys Hospital, London. For the last seven years he has been the principal lecturer and hands-on instructor for courses in Crown and Bridge technique and regularly speaks on the subject 36 Figure 17: Temporaries 14 days after placement.