Page 10 - The Beauty and Sorrow in Endodontics-Chapter 4 - Part 1

AA-3)? Is the tooth angulated (eg, mandibular molar crowns are tipped lingually and

maxillary molar crowns are tipped buccally) (Fig AA-4)? Is the tooth rotated or tipped
due to the loss of adjacent teeth (Fig AA-5, AA-6)? Prior to placing the rubber dam, a

probe can be used to gently assess the angulation of the roots. Modifications to the

access cavity prep must be made to take into account the individuality of each tooth to
allow for visualization of each canal orifice. When searching for MB2 in a maxillary

first molar, for example, since the roots are oftenmore splayed thanin second molars,

the MB2 will often be displaced more towards the mesial surface. Imagine a line
connecting the MB1 and P canals, now imagine another line starting from the DB

canal crossing perpendicularly to the first line, the point on the DB line mesial to the
intersection between the two is usually where the MB2 orifice can be found (Fig

AA-7a). In maxillary second and third molars, however, due to the close proximity of
the roots, the MB2 orifice often lies on the MB1-P line (Fig AA-7b).

Fig AA-1

The walls of the pulpal chamber are concentric to the
external outline of the tooth at the level of the CEJ
(Law of Concentricity) and the floor of the chamber
serves as a map to locate the various canal orifices.

Fig AA-2 Fig AA-3

Dentists can identify if one or Using the information above (Law of
more canals exist in each root Concentricity and Law of Symmetry),
through the Law of Symmetry. dentists can locate the various canal

orifices in each root once one is found.
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