Author/Authors :
M. Akhlaghi، Nahid نويسنده Department of Endodontics, Dental Branch, Islamic Azad University, , , Mashadi Abbas، Fatemeh نويسنده Department of Oral and Maxillofacial Pathology, Faculty of Dentistry, , , Mohammadi، Mostafa نويسنده Dentist in Private Practice , , Karami Shamloo، Mohammad Reza نويسنده Dentist in Private Practice , , Radmehr، Orkideh نويسنده Department of Dental Anatomy and Morphology, Dental Branch, Islamic Azad University, Tehran , , Kaviani، Ramin نويسنده Department of Dental Anatomy and Morphology, Dental Branch, Islamic Azad University, Tehran, , , Rakhshan، Vahid نويسنده Iranian Tissue Bank and Research Center, Tehran University of Medical Sciences, Dept. of Dental Anatomy and Morphology, Dental Branch, Islamic Azad University, Tehran, Iran. ,
Abstract :
Background: Root morphology is of utmost importance to endodontic sciences. Since there
are a few studies on the morphology of mandibular second molars’ roots, and some anatomical
variables are not evaluated before, the aim of this study was to investigate thoroughly radicular
anatomy of this tooth.
Materials and Methods: This ex vivo study was performed on 150 intact mandibular second
molars. After access cavity preparation and ensuring canal patency, Indian ink was injected into
root canals from the orifices. The teeth became transparent using methyl salicylate storage. Then,
they were inspected by an endodontist under a ×10 stereomicroscope regarding numerous
root morphological variables. Data were analyzed using chi?square test and analysis of variance
(? = 0.05).
Results: About 86.7% of teeth had two roots and 13.3% were single?rooted (P = 0.0001), of which,
50% were C?shaped (6.7% of all teeth, P = 0.0001). 86.7% of mesial roots were double canalled,
whereas 75.3% of distal roots were single canalled (P = 0.0001). 71.45% and 95.3% of the mesial and
distal roots had one apical foramen, respectively (P = 0.0001). Apical foramens were mostly central
followed by lingual in most cases. Distances between apical foramen and apical constriction ranged
between 0.27 and 0.40 mm (P = 0.0545). Distances between apical foramen and root apices ranged
between 0.30 and 0.47 mm (P = 0.0001). Vertucci classifications of mesial canals were Type II in 62.6%
and Type IV in 37.4%. 86.2% of single?canal distal roots were Type I. 66.7% of double?canal distal roots
were Type II and 33.3% were Type IV (P = 0.0001). The mean root lengths from cervical to apex
of mesial, distal, and single roots were 14.02 ± 0.85 (95% confidence interval [CI] = 13.87–14.17),
13.35 ± 0.91 (95% CI = 13.19–13.50), and 14.25 ± 0.72 mm (95% CI = 13.91–14.58), respectively.
The extents of canal curvatures varied between 20° and 31° buccolingually (P = 0.0000), and
between 19° and 27° mesiodistally (P = 0.0000).
Conclusion: There was a considerable rate of eccentric apical foramen in mandibular second molars.
