ROEN0210

I 21 clinical report _ apical microsurgery series I roots2_2010 are popular because of their ease of use. They both have good flowability, dual-cure properties and the ability to be bonded to dentine. Geristore is supported by research, demonstrating bio-compatibility to the surrounding tissues.5 The usual etching, conditioning of the dentine, insertion of the selected material, and curingbychemicalorlightisaccomplishedinaroutine manner when bonding into the retro-preparation. Note: Since the light source for the OM is so intense, it is mandatory to use an orange filter while placing the composite in order to prevent a premature set. Formostmicroscopes,anorangefilterisavailablethat easily and inexpensively replaces the blood filter. After thecompositehasbeencompletelycured,thematerial is finished with a high-speed finishing bur and the resectedroot-endisetchedwitha35%bluegeletchant (Ultradent)forabout12secondsinordertoremovethe smearlayerandtodemineralisethesurface. Several studies have demonstrated no leakage with bonding techniques and many operators use bonding as their technique of choice. However, there is some controversy as to whether the resected sur- faceoftherootshouldalsobecoatedwithathinlayer of the bonding material. A ‘cap’ of material (usually OptiBond) is placed with the intention of sealing the exposed tubules on the resected surface. Operators that choose to cover the resected surface believe it is necessarytoensureagoodsealandenablebetterpre- dictability.Otheroperatorsdonotbelievethatexposed tubules are a factor concerning the predictability of thehealingprocess.Theyreasonthatnothingwillheal as well or is more bio-compatible than the exposed dentineoftheapicallyresectedsurface.Idonotcover the exposed apical surface and am convinced that a decisive answer regarding this is still awaited. More recently, another material―MTA―has become very popular and is widely used by many. MTA has attracted many converts, and there is much research being conducted and many publications presented so that just one reference would be futile. The evidence extolling the virtues of MTA, regar- ding its sealing capabilities and its bio-compatibility withthesurroundingtissues,isoverwhelming.Ihave talked to many respected endodontists and most are now using MTA as their routine retro-fill material. MTA is chemically similar to calcium sulphate. It is forgiving to work with and has a radiopacity slightly better than gutta-percha (Fig. 1c). ThemainadvantageofMTAisitseaseofuse,much like handling Portland Cement. One of the secrets to using MTA is to keep it sufficiently dry so it does not flow too readily (like wet sand), yet sufficiently moist to permit manipulation and maintain a work- able consistency. The desired thickness is easily accomplished by using dry cotton pellets, or the MTA mix can be gently dried with a dedicated, air-only, Stropko Irrigator. If the MTA is too dry and needs moisture added, that too is easily done with a cotton pellet saturated with sterile water. Properly mixed MTA can be extruded in pellets of various sizes (depending on the size of the carrier used) using a Dovgan Carrier, and condensed with an appropriate plugger. More recently, a simple method for delivering MTA into the REP was introduced (Figs. 2a & b). The Lee MTA Pellet Forming Block has several differently sizedgroovestocreatethedesiredaliquotofMTA.The MTAadherestotheinstrument,allowingforeasyand efficient placement into the REP (Figs. 2c–e). Fig. 2e Figs. 2c–e_Using the Lee MTA Pellet Forming Block, it takes fewer ‘passes’—usually only two or three—with the instrument to com- plete the fill of the REP with MTA. Fig. 2d

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