Localization of root canal orifices in mandibular second molars in relation to occlusal dimension

Comparing the Traditional Versus Conservative Endodontic Access Cavities Design of the Maxillary First Molar: Using Cone-Beam Computed Tomography

Background

This study aimed to compare the size and location of the traditional and conservative endodontic access cavities of the right maxillary first molar teeth, projected on the occlusal surface using cone-beam computed tomography (CBCT), to obtain an ideal access cavity.

Material/Methods

Five hundred CBCT images of the right maxillary first molars, including 198 males and 302 females, were retrospectively evaluated using KaVo eXam Vision software. First, a rectangular coordinate system was established. The coordinates of 4 pulp horns and 3 root canal orifices, which projected on the occlusal surface, were marked on it. Two different access cavities were then created by connecting these points: (1) traditional endodontic access cavity (TEC) required removal of the entire roof of the pulp chamber to establish a straight-line access to the root canal system; (2) conservative endodontic access cavity (CEC) was formed by connecting the projection of each root canal orifice on the occlusal. Data were analyzed using Kruskal-Wallis and Pearson’s correlation tests at a 5% significance level.

Results

The area of TEC was approximately 9.61 mm² for males and 8.91 mm² for females. The area of CEC was approximately 3.4 mm² for males and 3.16 mm² for females. The projections of all pulp horns and root canal orifices were in or near the central area of nine-rectangle-grid.

Conclusions

Compared with the traditional access cavity, creating a conservative access cavity was less invasive. Meanwhile, the access cavity should be limited to the central or near the central area of nine-rectangle-grid.

Determination of canal orifice co-ordinates and MB2 incidence of maxillary first molars in a Turkish sub-population

OBJECTIVES

To measure the co-ordinates of the root canal orifices and to determine the incidence of mesiobuccal-2 (MB2) in maxillary first molars in a Turkish sub-population.

MATERIALS AND METHODS

Standard digital photographs were taken under a stereomicroscope from the occlusal aspect of each tooth (n = 176) before and after crown removal. Canal orifices were negotiated under moderate magnification using dental loupes. The coordinates of the orifices and the distances of each from the central fossa were measured by using geographic software. Intensity maps of the orifice locations were created by using the co-ordinates of all canal orifices. A representative map was drawn using the mean values of orifice locations and access projection area.

RESULTS

In the right maxillary first molars, the mean values for the (X, Y) co-ordinates were (0.67, 2.68) for mesiobuccal-1 (MB1), (0.81, 0.84) for MB2, (-1.12, 1.26) for distobuccal-1 (D1), (-0.89, 0.23) for distobuccal-2 (D2) and (0, -2.50) for palatinal (P); the corresponding mean values in the left maxillary first molars were (-0.78, 2.56), (-0.98, 0.90), (0.99, 1.18), (0.69, 0.78) and (0.00, -2.53), respectively. The average MB1-MB2 distance was 1.97 mm. Distobuccalcanal orifices were localized at the distal side of the center in 98.3% of teeth. The incidence of MB2 was 46.02%.

CONCLUSIONS

The distobuccal canal orifice is mostly located on the distal side of the central fossa. Thus, it should be considered that the access cavity of the maxillary molars may not be always limited mesially. The incidence of MB2 in this sub-population was 46.02%, which is of great importance clinically.