Steps in Access Opening
We can divide the complete process of access cavity preparation into seven distinct steps :
- STEP # 1 Relieve the tooth out of occlusion “Reduce Postoperative Discomfort”.
- STEP # 2 Use caries as a guide “Chase the caries”.
- STEP # 3 Laws of Access Opening “Know your Geography”.
- STEP # 4 De-roofing of pulp chamber “Most important rule of access opening”.
- STEP # 5 Observe the color change “Color is the language of Endodontics”.
- STEP # 6 Remove dentinal shelves “Establish straight-line access”.
- STEP # 7 Locating the Canal Orifices “Eureka Moment!!!”.
Laws Of Access opening in detail
Laws of a relationship of the pulp chamber to the clinical crown:
Law of centrality: The floor of the pulp chamber is always located in the center of the tooth at the level of the CEJ.
Law of concentricity: The walls of the pulp chamber are always concentric to the external surface of the tooth at the level of the CEJ.
Law of the CEJ: The CEJ is the most consistent, repeatable landmark for locating the position of the pulp chamber.
Laws of a relationship of the pulp chamber to orifices:
Law of symmetry 1: except for maxillary molars, the orifices of the canals are equidistant from a line drawn in a mesial-distal direction through the pulp-chamber floor.
Law of symmetry 2: except for the maxillary molars, the orifices of the canals lie on a line perpendicular to a line drawn in a mesial-distal direction across the center of the floor of the pulp chamber.
Law of Color Change: the color of the pulp-chamber floor is always darker than the walls.
Law of orifice location 1: the orifices of the root canals are always located at the junction of the walls and the floor.
Law of orifice location 2: the orifices of the root canals are located at the angles in the floor-wall junction.
Law of orifice location 3: the orifices of the root canals are located at the terminus of the root developmental fusion lines.
All the laws described previously are gathered in the following pictures: