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Endodontics


open apex Management of the


By Robert Smyth and Bob Philpott T


he anatomy of the apical foramen changes with age as root formation has yet to be completed when teeth erupt. The


completion of root development and closure of the apex occurs up to three years after eruptionı


. Patients who present with imma-


ture apical formation (see Fig ı) pose a challenge due to the presence of large open apices along with diver- gent and thin dentinal walls that are susceptible to fracture. Historically, we have tried to generate formation of an apical barrier by repeated placement of calcium hydroxide over many months, or more recently by immediate barrier formation with a Mineral Trioxide Aggregate (MTA) plug. Ideal management would involve


regeneration of new pulpal tissue and continued root formation. Novel techniques for dealing with immature apices such as apexo- genesis sometimes claim to be regenerative techniques. However, assessment of the composition of this regenerated tissue has proven to be difficult and it seems that it is made up of periodontal and bone tissue, rather than tissue of pulpal


Stage ı 2 3 4 5 Appearance Wide divergent opening, <50% root length Wide divergent opening, 50% root length Wide divergent opening, 66% root length Wide apical opening, nearly complete root Closed apical foramen, complete root length


Radiographs showing common


presentation of teeth with open apices and photographs showing gutta percha points following


Fig 1a


removal (note deposits on apical portion of extruded points)


Fig 1b Fig 1c origin2 . As clinicians, we need to


consider whether this is better than formation of an apical barrier and obturation by conventional means.


Root development (see Table) Classically, there are two types of open apices: blunderbuss and non-blunderbuss. In the former, the walls of the canal are diver- gent and flaring, the apex is funnel shaped and typically wider than the coronal aspect of the canal. In a


Fig 1d


non-blunderbuss apex, the walls of the canal may be parallel to slightly convergent. The apex, therefore can be broad shaped or convergent.


What are the causes of open apices? Incomplete root development often arises secondary to pulpal necrosis arising as a result of caries or trauma. Both foraminal and peri- foraminal resorption of the root end may also arise in the presence of a periapical lesion4


. This may alter the


anatomy of a pre-existing open apex further. Iatrogenic enlargement of the root end may also arise due to poor control of working length and subsequent enlargement with both hand and rotary files.


What problems are faced clinically? Teeth with open apices often tend to have thin dentinal walls that are susceptible to fracture before, during or after endodontic treatment.


Continued » Ireland’s Dental magazine 29


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