Prevalence of C-shaped mandibular second molars in Zahedan

Background: Incorrect diagnosis in internal anatomy and morphology of the pulp increases
failure probability in endodontics treatments. Thus, being familiared with possible anatomic forms
of tooth root canals is necessary. The aim of this study was prevalence assessment of C-shaped
canals in mandibular second molars of patients attending to the surgery department of Zahedan
dentistry school and dentistry centers in Zahedan 2006-2007.
Materials and Methods: In this study, a total number of 368 mandibular second molars of the
patients attending to surgery department of Zahedan dentistry school and city dentistry centers
were collected. Then access cavities were performed on the teeth with fused roots by high speed
handpiece with water spray and fissure bur. Teeth which had C-shaped orifices were separated
under direct dental unit light and 3x magnification . After that teeth were marked on three points:
CEJ, midroot, and 2mm to apex and were mounted in translucent acryl. Radiographic images were
taken from each tooth in faciolingual and mesiodistal aspects. Then 0.2mm thickness cross sections
were made by hand piece and diamond disc (D&Z). These sections were assessed under
stereomicroscope by 40 magnifications. C-shaped canal forms were categorized according to
Melton classification and their radiographic views were classified according to Fan classification.
Results: This research was performed on 368 mandibular second molars, out of which 312 teeth
(84.8%) had two separate mesial and distal roots. 56 teeth (15.2%) had fused roots 11 of which
(3%) had C-shaped canals. The number of teeth in each category and type was as following : 5
(1.35%) category I , 4 (1.08%) category II , 2 (0.57%) category III. Based on radiographic views
the number of teeth in each type was as following: 4 (0.36.4%) type I. 2 (18.2%) type II and 5
(44.4%) type III.
Discussion: Clinical significance of c-shaped canal is due to cleaning and obturation problems
of the canal. %3 prevalence of c-shaped canal in studied group of this survey showed the necessity
of clinician care for better diagnosis and treatment and higher success rate of root canals
treatments.