Australasian Dentist Magazine May June 2021

Category 68 Australasian Dentist recommended curing time is 10s. It is essential to bring the curing light really close to the restoration surface to ensure an adequate cure in 3 seconds. If in doubt, I recommend that the 3-s program is activated twice, by which the curing time is increased to 6s. The curing light can be activated twice consecutively. After the second time, however, it forces a break of 30 seconds to protect the pulp from becoming overheated by being exposed to multiple curing times at short intervals. This safety feature does not present an impediment. Should an additional increment be needed, more than 30s will pass anyway until the composite is applied and adapted. Those who delegate the polymerisation procedure to their practice assistant are advised to activate the light-curing assistant built into the latest generation of the Ivoclar Vivadent curing lights (Bluephase G4 and PowerCure), at least initially. The light-curing assistant measures the light reflected back from the tooth surface to the light guide. If the value measured falls below the threshold value, the curing light assumes that the distance to the restoration surface is too wide to ensure an adequate cure and will switch off within 100ms. Users a given an acoustic alert to warn them to repeat the curing procedure correctly. This feature makes perfect sense, as all essential quality parameters (abrasion, fracture resistance, shade stability and marginal integrity) depend directly on achieving an adequate depth of cure (Price 2012). Generally, polymerisation is still not given the attention it ought to be given, considering the fact that 11% of the curing lights used in dental practices in Germany fail to meet the minimum performance requirements and only half of the practices check the performance of their curing light on a regular basis (Ernst et al. 2018). Once the first cavity was filled, the separation ring was removed, and the matrix band of the restored cavity loosened and pulled out from the side. The matrix band should always be pulled in the direction of the tip of the separation wedge (Fig. 22). This way, the matrix band of the adjacent cavity remains in position. Once the matrix was removed, the separation ring was reinserted (Fig. 23). This procedure resulted in a tight contact between the adjacent restorations exactly at the centre of the interdental space. Figure 24 shows the restored cavities immediately after the removal of the matrix band. Occlusal contacts that lie directly on the proximal marginal ridges (Fig. 25) should be removed completely when finishing and polishing the restoration to prevent the risk of proximal chipping during exposure to masticatory forces (Fig. 25). Fracturing has been cited as the main reason for the failure of composite restorations (Heintze and Rousson 2012). This problem can be significantly reduced by following the above rule. Figure 26 shows the completed restorations. Final considerations Purists may be content with using a universal composite as the only direct restorative material in their practice. However, I consider bulk fill composites to be the material of choice for the routine restoration of Class I and II cavities. Clinically equivalent to conventional composites, they facilitate the clinical procedure and shorten the vulnerable phase of the restoration, especially if no rubber dam is used for isolation. In addition, the 4mm composites Tetric PowerFill and Tetric PowerFlow presented here offer the possibility of ultrashort curing times in conjunction with the innovative Bluephase PowerCure light, if such a procedure is preferred. For the anterior region or for posterior restorations involving esthetically sensitive areas, Tetric Prime is suitable for all additional indications occurring in everyday practice work. u For a full list of references contact gapmagazines@optusnet.com.au Fig. 21 Tooth 34 after restoration of the cavity (yellow arrow) using a single layer of Tetric PowerFill and the 3-s curing program of the PowerCure light unit. Removal of the separation ring (red arrow). Fig. 23 The separation ring is reinserted. When the second cavity is restored, only one matrix band remains in the interdental space and a tight contact can be generated without any difficulty. Fig. 25 Occlusal check: Contacts that lie directly on the proximal marginal ridge should be removed completely. Fig. 22 The matrix band of the restored tooth 34 is slightly loosened and pulled out from the side. The matrix band should always be pulled out in the direction of the tip of the separation wedge (yellow arrow). This way, the matrix band of the adjacent tooth remains in position. The matrix band can usually be removed with a pair of tweezers, if not, pliers can be used to grasp it. Fig. 24 Situation after restoring the cavity on tooth 35 and removal of the matrix bands. Fig. 26 Completed restorations immediately after the treatment. clinical