Background and Objectives: The success of root canal therapy is depending on cleaning and shaping of the root canals. The root canals have complex morphology and wide individual variations. The purpose of this study was to investigate the prevalence of second mesiobuccal canal (MB2) of maxillary first molars in Erbil population using cone beam computed tomography (CBCT). Materials and Methods: A total of 101 permanent maxillary first molars were randomly se-lected from Erbil citizens. All teeth were examined for the number of root canals and the pres-ence of second mesiobuccal canal by Cone Beam Computed Tomography (CBCT). Result: The MB2 canal was found in 80.2% (the 95% CI is 72.3% to 87.1%) of the analyzed cas-es (81/101). Conclusion: The second mesiobuccal canal was found in a high percentage of the samples. And it is within normal magnitude in comparison with the common findings in the literature. These results indicate that CBCT is an effective, high-precision diagnostic tool for detecting canals. Keywords: Maxillary first molars, second mesiobuccal canal, cone beam computed tomography, Erbil Citizens.

The pulp-dentin complex regenerates the damaged coronal dentin, resorbed root, cervical or apical dentin. Regenerative procedures are to be done with the use of tissue engineering materials, stem cells and suitable biochemical factors that will enhance or replace biological functions. Largely the objective of tissue engineering is the functional restoration of tissue structures. Clinical applications depends on the use of a potential material which would be antiinflammatory, antibacterial and can simultaneously enhance the proliferation and induce the differentiation of the present Dental Pulp Stem Cells (DPSC) into odontoblast-like cells leading to dentin formation. Formation of a reparative dentin layer would provide an optimal barrier to avoid any bacteria infiltration to the pulp tissue, which is not provided by any artificial restorative materials. So application of a scaffold on an open pulp enabling odontoblast-like cells to grow into the scaffold and to convert it into dentin would be an ideal goal. Regenerative endodontics comprises research in adult stem cells, growth factors, organ-tissue culture, and tissue engineering materials.