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2- Access cavity prepration (record) l Endodontics series


1st record  

2nd record  

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Introduction :

  • The accesspreparation starts the clinical process of root canal treatment. The American Association of Endodontics defines access cavity as "the opening prepared in a tooth to gain entrance to the root canal system for the purpose of cleaning, shaping and obturating."l Historically, access cavity preparations have been limited by the available tools and materials and the clinician's specific needs.
  • Despite advances in technology, materials, and instrumentation, the access cavity preparation designs that are taught in dental schools and residency programs and used by most practicing clinicians have changed little over the past several decades. Preservation of the structural integrity of the tooth has taken a back seat to making the endodontic procedure easier, quicker, and less risky.
  • Endodontic access requires removal of internal tooth structure to meet the needs for endodontic treatment, and restorative procedures generally require removal of external tooth structure. Yet the restorative community has increasingly recognized the need for and importance of retaining natural tooth structure as well as the important role of pericervical dentin in both the restorability and survivability of teeth. Therefore, access cavity preparations that preserve structural dentin are likely to positively influence the life span of the tooth.
  • The approach to access cavity preparations discussed in this record allows for adherence to a high standard of excellence in endodontic treatment while maintaining the structural integrity of the tooth.

Outline

  1.          Instruments.
  2.            Most important thing in an access.
  3.            Modern concepts.
  4.            How to preserve tooth structure?
  5.            How to find the anatomy (canals)?

Instruments

  •          Round bur to gain access.
  •          Tapered Stone or Endo-Z bur for deroofing.

  1.          There are access cavity kits available in the market (including transmetal burs for gaining access through porcelain fused to metal crowns, and diamond stones for gaining access through porcelain).
  2.       The instruments size should be corresponding with tooth size, use small sized round bur for lower anteriors, medium sized for upper anteriors, canines and premolars, and large sized for all molars.

Deroofing

  1.             Most important step om access cavity.
  2.           All the roof should be removed to eliminate all pulp tissues under it.
  3.           Presence of roof will make stress concentration on file, this is added to stress   during entering canal, added to more stress if there is curved canal, all these   will lead to breakage or instrument separation.
  4.           To see all anatomy and make it easy to negotiate and clean all the canals.

Steps of access cavity preparation

  •        Gaining access by round bur, in lingual surface of anteriors and occlusal surface of molars.
  •        Deroofing.
  •         Flaring by safe ended diamond stone or Endo-Z bur or tapered stone, extend until there is visual and instrumental convenience, but there should be balance between convenience and over-flaring as it causes weakening to the tooth structure, so you should make biological and mechanical balance.