The internal anatomy of danger zone of mandibular molars: A cone-beam computed tomography study
Sheila Silva Leite Pinto1, Renata Ximenes Lins2, Marília Fagury Videira Marceliano-Alves3, Michelle Da Silveira Guimarães4, Barbara Alves Da Fonseca2, Antonio Ermelindo Radetic2, Ália Regina Neves De Paula Porto5, Hélio Pereira Lopes2
1 Department of Endodontics, Brazilian Association of Dentistry, ABORJ, Nova Iguaçu, Rio de Janeiro, Brazil
2 Department of Specific Training, Nova Friburgo Health Institute, Fluminense Federal University, Nova Friburgo, Rio de Janeiro, Brazil
3 Department of Endodontics, Estácio de Sá University, Nova Iguaçu, Rio de Janeiro, Brazil
4 Department of Specific Training, Nova Friburgo Health Institute, Fluminense Federal University, Nova Friburgo; Department of Endodontics, Estácio de Sá University, Nova Iguaçu, Rio de Janeiro, Brazil
5 Department of Endodontics, Iguaçu University, Nova Iguaçu, Rio de Janeiro, Brazil
Prof. Marília Fagury Videira Marceliano-Alves
Rua Siqueira Campos, 59 - Sala 303 - Copacabana, Rio de Janeiro - RJ, 22031-072
Source of Support: None, Conflict of Interest: None
Aim: The aim of this study was the assessment of the anatomical thickness of danger zone in the cervical third of mesial canals of mandibular molars.
Materials and Methods: Fifty mandibular molars were selected and scanned with cone-beam computed tomography. Data were compared using a length tool provided by scanner software. The measured areas were the mesial and distal walls of the cervical third of the mesial roots, which correspond to the safety and danger zones, respectively. In addition, dentin thickness at the furcation was evaluated.
Results: Dentin thicknesses of the safety zone were higher than in the danger zone in all teeth examined. The thinnest dentin of the safety zone was found at a point located 4 mm below the canal orifice, with a mean value of 1.03 mm; conversely, in the danger zone, the thinnest point was located 3 mm below the orifice, with a mean value of 0.81 mm. As for the distance from the pulp chamber floor to the furcation, the average value was 2.23 mm.
Conclusion: These results show that mean thicknesses at the danger zone of mandibular molar mesial roots were <1.0 mm. These data reinforce the importance of understanding anatomy and the need for conservative preparations when assessing and instrumenting these root canals.