No abstract

Traditional teaching of the anatomy of root canals in different teeth can lead clinicians into the misguided belief that a predetermined number of root canals is always present in any given tooth. A new understanding of the root canal system has enabled the location of additional canals. Results of the clinical study of 760 first mandibular molars, showed that 20 (2.6 per cent) had three canals in the mesial root. Of these 20 teeth, 13 (65 per cent) had an intermediate canal which joined the mesiobuccal canal in the apical third. In six cases (30 per cent) it joined the mesiolingual canal in the same area. In only one case did the intermediate or third canal retain its individual nature and end in an independent foramen.

No abstract

Under the conditions of the study, the Quantec Series 2000 rotary system was simple and safe to use, and created good three-dimensional mechanical preparation of natural canals.

Tooth fracture by impact is the most common cause of fracture in human incisors. We have designed an experimental system to measure the dynamic fracture force of teeth in vitro, and initial results obtained from a sample of healthy, recently removed human incisors are reported. The method was reproducible and reliable, and the results provide a baseline for studies evaluating the effect of endodontic procedures on the dynamic fracture force of teeth.