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cde0411

Recent developments in composite resin materials and bonding technology have made the routine use of these materials in posterior teeth possible.1 Direct posterior composite resin restorations are now predictable and durable, and in many instances their superior aesthetic and tooth-supporting properties make them the ideal treatment option when restoring the posterior dentition.2 The main shortcomings of composite resin materials are polymerisation shrinkage3 and polymerisation stress. Polymerisation stress can result in contraction forces on the cusps that can result in cuspal deformation,4 enamel cracks and ultimately decrease the fracture resistance of the cusps.5 ...

18 I I clinical technique _ SDR _Recent developments in composite resin materials and bonding technology have made theroutineuseofthesematerialsinposteriorteeth possible.1 Directposteriorcompositeresinrestora- tionsarenowpredictableanddurable,andinmany instances their superior aesthetic and tooth-sup- porting properties make them the ideal treatment optionwhenrestoringtheposteriordentition.2 The main shortcomings of composite resin materials are polymerisation shrinkage3 and polymerisation stress. Polymerisation stress can result in contrac- tion forces on the cusps that can result in cuspal deformation,4 enamel cracks and ultimately de- crease the fracture resistance of the cusps.5 Cavity configuration and the method of in- sertion of composite resin into the cavities can influence the gaps at the interface between the dentine/enamel and the restoration.6 According to Davidson and De Gee,7 the parallel walls of a box-shaped cavity may restrict the flow of com- posite during polymerisation, causing stresses at the resin–dentine interface.8 The present generation of chemically or light- activated flowable composites undergoes free volumetric shrinkage of 4 to 9 % as compared with regular viscosity and packable composites at 2 to 5 %, with an average of 3.5 %. According to Jensen and Chan, polymerisation shrinkage stresses have the potential to initiate failure of thecomposite–toothinterface,whichcouldcause deformation of the tooth, which in turn might re- sult in post-operative sensitivity and which could even open pre-existing enamel microcracks.9 SDR Smart Dentin Replacement (DENTSPLY DeTrey) is marketed as a low stress flowable base materialthatcanbeplacedinlayersofupto4mm cosmeticdentistry 4_2011 Clinical application of a new flowable base material for direct and indirect restorations Author_ Prof Peet van der Vyver, South Africa Fig. 3a Fig. 2Fig. 1 Fig. 3b