Morphology and prevalence of middle canals in the mandibular molars: A systematic review

Abstract

Objectives:The purpose of this paper is to systematically review the various studies and case reports on the morphology and prevalence of middle canals in the mandibular molars.Methodology:Electronic databases such as MEDLINE, PubMed, EBSCOhost, ScienceDirect and various journals were screened to identify published literature till March 2017 and earlier for articles related to middle canals in the human permanent mandibular molars. Obtained articles were categorized as original researches, case reports and review articles. Well-defined review questions were developed using the patient population, intervention, comparison and outcome framework to summarize the objectives: “Does middle canal vary in morphology and anatomic location? What is the prevalence of middle canals in mandibular molars? Does ethnicity affect the prevalence of middle canals in mandibular molars?” Morphology was studied and prevalence rates were determined from the evaluation of data extracted from the articles.Results:The search strategy resulted in 87 articles, of which 36 were original research papers and 51 were case reports. The prevalence of middle canals in the various populations ranged from 0.26% to 53.8%. Middle canals were reported in Europeans, Asians, Africans and South and North American populations. The prevalence of middle mesial canal and middle distal canal in various races was reported as up to 53.8% and 10%, respectively. The orifice of middle canal exists below a dentinal projection in the groove between the two main canals. They were observed in fin, confluent and independent configuration. Out of these, confluent configuration was more prevalent.Conclusion:Middle canal varies in morphology and anatomic location. Ethnicity affects the prevalence of middle canals in the mandibular molars.

Never Miss on the Extras: Middle Mesial Canal an Extra Entity

“…The mean minor diameter of the Middle Mesial Canal orifice is seen to be 0.16 mm, which is three times less than that of two main orifices (0.50 mm) [4] . Clinically troughing through the mesial pulpal groove in a mesio-apical direction helps in detection and negotiation of MMCs.…”

Cone-beam Computed Tomography Investigation of Middle Mesial Canals and Isthmuses in Mandibular First Molars in a Chinese Population

“…The reasons for these different results may be due to different voxel sizes of CBCT machines and ethnicities of populations according to the latest systematic review. [6] CBCT is primarily utilized in pre-treatment clinical contexts, making it an valuable technique for establishing the presence of isthmuses and MM canals in areas of operative interest. Chavda and Garg proved that CBCT's detection accuracy of MM is not inferior to magnification and troughing in an in vitro study [24].…”

“…Indeed, many approaches have been employed for assessing the presence of MM canals, with estimated frequencies from 0.26% to 53.8% [6][7][8][9]. Isthmus frequencies have been found to range from 20-70% [2,[10][11][12].…”

Cone-beam Computed Tomography Investigation of Middle Mesial Canals and Isthmuses in Mandibular First Molars in a Chinese Population

“…Indeed, many approaches have been employed for assessing the presence of MM canals, with estimated frequencies from 0.26% to 53.8% [6][7][8][9]. Isthmus frequencies have been found to range from 20-70% [2,[10][11][12].…”