Tooth preparation for post-retained restorations

Abstract

Failure of root canal treatment and/or post crowns can be avoided in many cases if appropriate tooth preparation is carried out. This paper discusses the rationale for the timing of post placement following root canal treatment and appropriate methods for removal of gutta-percha prior to post space preparation. The basic principles of post space preparation are described, which should reduce the risk of weakening the root unnecessarily, causing damage to the periodontium and post perforation.  The timing of post placement following root canal treatment is critical to maintain an apical seal to the root filling and provide a coronal seal to the root canal system.  Appropriate gutta-percha removal and post space preparation is important to prevent unnecessary weakening of the root dentine, damage to the periodontium and post perforation.  Within the limitations of root length, curvature and maintaining 4-5 mm of apical guttapercha for an apical seal, post length is critical to retention of post-retained crowns.  Preservation of coronal tooth tissue is important in order that a ferrule can be created, reducing the risk of root fracture.

Management of a Complicated Crown Fracture in a Tertiary Care Hospital

“…Mechanical removal of gutta-percha point using Gates-Glidden drill or peeso reamer is efficient and probably is the most commonly used technique, but it is associated with a higher risk of root perforation if carried out incorrectly. 14 To avoid this problem, in this case, peeso reamers were used on slow speed with continuous up and down motion along with cooling arrangement. The method used to place the cement into the canal before placement of post has a significant effect on post retention.…”

A comparison of the survival of fibre posts cemented with two different composite resin systems

“…It has been estimated that the overall success rate of endodontic therapy performed in general dental practice in the UK is in the region of 61-77%. 36 Undoubtedly, failures will therefore occur associated with endodontic complications as opposed to mechanical failures linked with any particular post system. However, resin fi bre posts are relatively easy to remove, 37 thus permitting endodontic re-treatment (orthograde) without the added risks of root fracture upon post removal.…”

Efeito do pino intra-radicular e da presença de férula na resistência de dentes tratados endodonticamente

“…Neste estudo, quando foi comparada a resistência à fratura dos dentes tratados endodonticamente restaurados com os diferentes tipos de pinos intra-radiculares, foi possível observar que, na presença da férula, independente do tipo de pino utilizado, a resistência do dente restaurado foi significativamente maior. Os dentes que apresentavam remanescente dentário coronal (férula) restaurados com núcleos metálicos fundidos RAVNHOLT, 1999;LONEY;KOTOWICS;McDOWELL, 1990;RICKETTS;TAIT;HIGGINS, 2005) observaram que quanto maiores os remanescentes dentários coronais (férula), maior a resistência à fratura dos dentes a serem restaurados.…”

“…Alguns estudos (BRAVIN, 1976;STANDLEE, 1976;SIRIMAI;RIIS;RAY JUNIOR, 1992) têm demonstrado que a colocação de um pino intra-radicular pode gerar um maior estresse durante a função, levando, assim, à fratura radicular, outros (AKKAYAN et al, 2002;ASSIF et al, 1993;BARKHORDAR;RADKE;ABBASI, 1989;GEGAUFF, 2000;HOAG;DWYER, 1982;PEREIRA, 2003;PEREIRA et al, 2005;PEREIRA et al, 2006;PIERRISNARD et al, 2002;RICKETTS;TAIT;HIGGINS, 2005;ZHI-YUE;YU-XING, 2003) mostram que a resistência de dentes tratados endodonticamente está diretamente relacionada à quantidade de remanescente dentário presente. Dessa forma, quando não existe remanescente dentário coronal suficiente, os pinos intra-radiculares devem ser indicados para suportar uma coroa (ASSIF et al, 1989;COHEN et al, 1996;GELFAND;GOLDMAN;SUNDERMAN, 1984;GUZY;NICHOLLS, 1979;RAY JUNIOR, 1992).…”

“…Vários autores (SORENSEN; ABOU-RASS, 1978;WALDNILD;MUELLER, 2001) têm sugerido que um dente deveria ter uma quantidade mínima de 2mm de estrutura coronal acima da junção cemente-esmalte para garantir uma forma de resistência adequada para o dente. Essa estrutura coronal providenciará um efeito férula com a coroa artificial que deverá prevenir a fratura da raiz, fratura e deslocamento do pino (AKKAYAN et al, 2002;ASSIF et al, 1993;BARKHORDAR;RADKE;ABBAS, 1989;GEGAUFF, 2000;HOAG;DWYER, 1982;PEREIRA et al, 2006;PEREIRA et al, 2005;PEREIRA, 2003;PIERRISNARD et al, 2002;RICKETTS;TAIT;HIGGINS, 2005;ZHI-YUE;YU-XING, 2003).…”