Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2016-01-20, 13:53:08 | version 1.38.0
24 I I case report _ composite restoration So where does this lead us in a suggested modi- fication of our restorative technique for placing a core in an endodontically treated tooth? Currently, when there are enough walls and tooth structure left,manycliniciansinsertabulkfill,dual-curecom- positeresinintotheendodonticaccessopening(the same material as that used for cementing the fibre post) and then cure it all at once with an LED curing light. As already mentioned, this bulk fill not only creates a challenge for proper depth of cure and maximum physical properties on polymerisation, which will be addressed later in this article, but the large volume/amount of composite inserted, nega- tivelyaffectstheintegrityofadhesionandincreases microleakage. The typical access opening, which is essentiallyaverydeepClassIcavitypreparation,not onlyrequiresalargeamountofcomposite,butaswell, places the composite in the highest C-factor cavity preparation configuration of five. Only when utilis- ingacompositedeepinthepreparedrootcanal,has theC-Factorclaimedtobehigherat200toinfinity.39 The suggested solution to the high polymerisa- tionandcontractionstresscausedbybulkfillingthe accessopeningistoreducethemassorbulkofcom- posite by placing multiple Fiber Post Segments into the composite mass, before curing with the LED light.Ithasbeenconclusivelyshownthatevenwhen the C-Factor is at 200 or more in a prepared root canal, minimizing the thickness of the composite (the mass), results in less contraction stress (S-Fac- tor) which increases the patency of the bond to the root canal walls decreasing microleakage.40-43 Of course, the placement of inserts into composite is not a new idea. Glass ceramic inserts and beta quartz have been used to decrease composite vol- ume and later silica glass and ceramics were intro- duced as a method for post-composite insertion bulk reduction.44-46 These techniques demonstrated increased marginal patency and less microleakage, but the inserts were difficult to contour and polish with adhesion between the inserts and the com- posite being a challenge.47,48 Composite megafillers were introduced later, as these were essentially the sameasthematrixofthebulkfilledcomposite,elim- inating the inherent chemical differences between the materials.49,50 The authors suggest the insertion of multiple high quality, high capacity, light con- ductingfibrepostsegments(notallfibrepostscon- duct light efficiently51,52). This is not only to reduce the composite volume, thereby minimizing the po- tential for microleakage, but is also equally as criti- cal to use the light conductance of the fibre post segments to significantly increase the degree of polymerization of the dual-cure composite resin cements/core materials deep in the access opening, thereby increasing their physical properties.53 In their review of polymerisation shrinkage, Cakir et al discuss the attenuation of light, which Fig. 6_Completion of the debridement of the canals after rubber dam isolation with a better view of the extent of the distal crack line. Fig. 7_The root canals have been obturated with gutta percha, a couple of mm below the level of the pulpal floor. Fig. 8_After placement of the phosphoric acid (UltraEtch Ultradent) a microbrush is used to agitate the acid to clean the dentin, rinsed and lightly dried. Fig. 9_MPa bonding agent is applied to a microbrush and agitated into the tubules, followed by evaporation of the solvent with an air-only line. Fig. 10_The bonding agent is cured for 10 seconds with a Valo curing unit (Ultradent). roots1_2015 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10