cosmetic dentistry_ beauty & science

I 17 special topic _ composite restorations I cosmeticdentistry 1_2013 Bulk-cure Bulk-fill, fixed viscosity composites such as Quixx and Surefil SDR Flow, Tetric EvoCeram Bulk Fill, Venus Bulk Fill, and x-Tra Fil (VOCO) offer a depth of cure of only 4 mm. In contrast, SonicFill is a true bulk-fill resin with a higher depth of cure up to 5 mm, compared to analogousproducts. Strengthandlongevity The survival of a composite, especially in the poste- riorregions,isdeterminedbyitsabilitytoresistocclusal loads and maintain its anatomical form. Another ad- vantageoftheSonicFillresinisthatduetoitsfavourable strength, a capping occlusal layer is obviated, and re- search has confirmed that the high flexural strength (186 MPa) and compressive strength (254 MPa) of the SonicFill composite is comparable, or even great than severalconventionaluniversalcomposites.15 Reducedtranslucency In order to achieve a greater depth of cure, many bulk-fill deep resins are highly translucent to allow the curing light to sufficiently penetrate to the bottom of asingleincrementallayer.Unfortunately,theincreased inherenttranslucencyofmaterialssuchasQuiXFilcom- promisesaestheticsbyhavingagreyishappearancedue to low value, which is unsightly and readily noticeable. Ontheotherhand,theSonicFillresinisrelativelyopaque andavailableinavarietyofVITAshades,A1,A2,A3and B1 and when appropriately polished, yields acceptable aesthetics. _Clinical applications The salient feature of the SonicFill system is fluctuating viscosity, and in clinical prac- tice, varying viscosities offer vast versatility. In addition, the expediency for the provision of posterior white fillings is par- ticularly beneficial for patients with limited compliance, such as the elderly or medically infirm who cannot endure protracted sessions for incremental layering, fissure stainingandaresatisfiedwithmediocreaesthetics.The clinicalapplicationsofSonicFillincludeposteriorwhite fillings, coronal or core build-up, and cementing or- thodonticbracketsandfixedretainers. Posteriorfillings The obvious use of a bulk-fill deep resin is resorting Class I, II and VI cavities in posterior teeth. These can eitherbenewfillingsorthosethatrequirereplacement duetodefectivemargins,marginalditching,wear,poor morphology or bulk fractures, which applies to both failingamalgamandcompositerestorations.Inorderto retain an amalgam filling, creating undercuts are nec- essary(Fig.14).However,afterremovingtheoffending amalgamfilling,theremainingundercutsrequireoblit- eratingtosealthecavityfloor.Thiscanbeaccomplished by reduction of the axial walls to remove the unsup- ported enamel, which is destructive and unnecessarily. An alternative method for obliterating the undercuts is sealing them by exploiting the initial low viscosity of the SonicFill resin, which flows into the undermined areastopreserveexistingtoothsubstrate. All composite resin fillings are particularly suscep- tible to hydrolytic degradation over time. This causes ditching, microleakage, loss of contours or even cata- strophicfracture,whichcanresultinsensitivity,second- arilycariesorendodonticcomplications.Replacementof olddefectivecompositefillingswithSonicFilliseffortless and straightforward to restore occlusal form, provide Fig. 30_A palatal cusp fracture on a maxillary premolar with endodontic involvement. Fig. 31_The lost palatal cusp is built-up with SonicFill resin to isolate the tooth from oral fluids before preparing an access cavity for root canal therapy. Fig. 32_A fractured maxillary first premolar at the level of the gingival margin. Fig. 33_Following root canal therapy, two fibre posts are placed to retain a core build-up. Fig. 34_A core build-up using OptiBond XTR with SonicFill resin for supporting a definitive crown. Fig. 31 Fig. 32Fig. 30 Fig. 34Fig. 33