ROEN0410

06 I I case report _ open-apex retreatment _Owing to the lack of apical constriction, root- canaltreatmentofpermanentteethwithopenapices poses great challenges. When it comes to the endo- dontic treatment of such teeth, debridement and obturation of the canal space create a significant problem.Thewide-opencanalandthindentinalwalls are difficult to clean and shape, and it is even more difficult to obtain an acceptable conventional apical seal.Formanyyears,apexificationwasthetreatment of choice. The main goal of this procedure is to con- trol the bacterial infection and establish a suitable environment for the induction of calcified tissue into the apical area. Calcium hydroxide—Ca(OH)2—has remained the most acceptable intra-canal medica- ment used for apexification.1 However,thisprocedureisassociatedwithanum- berofclinicalproblems,suchasprolongedtreatment time, unpredictability of apical closure, difficulty in patient follow-up and susceptibility to fracture. Moreover,long-termuseofCa(OH)2 asanintra-canal medicamentcanweakenthethindentinalwallsofan immature root to a greater extent.2 Inordertooverridethedisadvantagesoftheapex- ification technique, many alternatives have been suggested that aimed mainly at the development of a one-step procedure (one-visit apexification). Some of these potential alternatives were abandoned due to limitation in the availability and bio-compatibility of the materials.3,4 Mineral trioxide aggregate (MTA) has been pro- posed as a material suitable for one-visit apexifica- tion.Itcombinesbio-compatibilityandbacteriostatic action with favourable sealing ability when used in contactwithbonetissue.5–8 MTAoffersanacceptable barrierattheendofrootcanalsinteethwithnecrotic pulps and open apices. This apical plug provides safe bio-compatible constriction that permits vertical condensationofwarmgutta-perchaintheremainder of the wide canal. For some, the intra-canal delivery technique is crucial for the adaptation and the qual- ity of the apical MTA plug.9 Moreover, the use of an operatingmicroscopemayallowbettercontrolofthe placement of the MTA apical plug.9 Following, the microscopic retreatment of an open-apex central incisor is described. Extruded through the open-apex, gutta-percha cones were re- trievedsuccessfullyundermagnificationandcomple- tionofthetreatmentwasachievedwiththeplacement ofanMTAapicalbarrier.Clinicaltipsfortheprocedure are provided and the predictability of the technique is considered. Fig. 1_Pre-op radiograph of right maxillary central incisor. roots4_2010 Open-apex retreatment under the operating microscope Author_ Dr Antonis Chaniotis, Greece Fig. 1