cosmetic dentistry_ beauty & science

I 15 special topic _ composite restorations I cosmeticdentistry 1_2013 Fig. 15_A pre-operative defective mesio-occlusal composite restoration in maxillary right molar showing marginal breakdown, ditching and poor occlusal anatomy. Fig. 16_After removing the filling, a MetaFix (Kerr, Switzerland) matrix band and wooden wedge are placed to shape the filling and obtain a tight proximal contact point, respectively Fig. 17_A burnisher or LM-Arte Condensa (LM-Instruments Oy, Parainen) is used to adapt the mesial aspect of the matrix band to the distal aspect of the anterior second premolar. Fig. 18_After applying the bonding agent, the SonicFill deep resin is dispended into the cavity. Fig. 19_Once the SonicFill tip is removed, the resin returns to a high viscosity state that is ideal for contouring the resin with a variety of hand instruments. A flat-plastic or LM-Arte Applica (LM-Instruments Oy, Parainen) is used for creating cuspal inclines. Fig. 20_A LM-Arte Fissura (LM-Instruments Oy, Parainen) is used for defining fissures. Fig. 21_A carver or LM-Arte Fissura (LM-Instruments Oy, Parainen) is used for shaping the marginal ridge. Fig. 22_Having sculpted and contoured the resin, the restoration is light cured and ready for finishing and polishing. operative sensitivity. Numerous newerlowshrinkageresinsoffer <2%contraction,andthehighly filled(>83%byweight)SonicFill resinhasshrinkageofonly1.6%. Furthermore, the associated re- duced stresses of 3 MPa are lo- wercomparedtomanyuniversal composites, which translates to the positive assumption that gap-free restorations are possi- blewithbulk-filldeepresins.9 Isa“flowable”composite strongenoughtoresistocclusalforces? Flowable composites, by definition, are weaker ma- terialsduetoreducedfillercontentforloweringthevis- cosity of the material, and are therefore unsuitable for occlusalloadbearingsurfaces.ClassI,II,andVIcavities requirehighstrengthandhighwearresistantcompos- itestomaintainocclusalmorphology. Research has confirmed that universal composites function adequately under normal occlusal forces.10 Although SonicFill transiently becomes flowable by applying sonic energy, it is essentially a high viscosity, highly filled composite with a compressive strength of 254 MPa, great than several universal composites.11 In addition, it displays a bottom to top Rockwell hard- ness ratio of 86 % making it ideal for resisting occlusal forces. Can a 5 mm increment be completely polymerised toitsfulldepth? The maximum thickness recommended for most universalandflowablecompositesis2mmforensuring adequate bottom to top polymerisation of the resin. The conversion of the monomer matrix to a polymer is primarily dictated by the formulation of the resin material. Nevertheless, many studies have concluded that the depth of conversion of bulk-fill composites is aviablepossibility.12–14 ThegreateramountofphotoinitiatorsintheSonic- Fill composite resin allow a high degree of conversion ratio, more than 86 %, to a full depth of 5 mm (Fig.12). Therefore, the proverbial 2 mm layer thickness is an antiquatedguidelineforbulk-fill,deepresins. Areaestheticscompromisedusingasingle monochromaticlayer? Althoughaestheticsareparamountfortheanterior regionofthemouth,andindeed,successisoftenjudged by the appearance of the restoration, posterior resto- rations are not assessed with the same critique. Innu- merableclinicians,includingtheauthor,havepublished articles showing beautifully carved posterior compos- ite fillings with intricate fissure patterns and staining that impeccably mingle with the surrounding tooth substrate. From an aesthetic perspective, these im- maculatefillingsareunquestionablyflawless. However, others frown at such “perfection”, stating thatitisanexerciseinself-indulgence,addinglittlefunc- tional or health benefits, to which a patient is totally in- different. This is further elaborated by pointing out that patientsdonotnoticethismeticulousworkortheeffort requiredforachievingthesehighlyaestheticrestorations (especially in maxillary molars). Further criticism is that patientsareunlikelytophotographtheirposteriorteeth, enlargetheimages,andneitherscrutinisenorappreciate thearduouseffortforcreatingsuch‘masterpieces’. Fig. 19 Fig. 21Fig. 20 Fig. 22 Fig. 15 Fig. 17Fig. 16 Fig. 18