AN EVALUATION OF CANAL MORPHOLOGY AT DIFFERENT LEVELS OF ROOT RESECTION IN MANDIBULAR INCISORS

One hundred randomly selected mandibular incisors were examined to ass ess the prevalence and location of two canals and to describe the cana l anatomy that may be encountered during apical surgery. Sections of t he root were cut at 1, 2, and 3 mm from the apex, simulating a 20-degr ee beveled surgical resection, The sections were digitally imaged at x 50 magnification, and canal dimensions were measured using imaging so ftware, The prevalence of two canals was 2% at 1 mm, 0% at 2 mm, and 1 % at 3 mm, At these levels in the roots, the canal was rarely divided by hard tooth structure. An isthmus of tissue was present 20% of the t ime at 1 mm, 30% at 2 mm, and 55% at 3 mm, Four distinct canal types w ere noted: (i) round, (ii) oval, (iii) long oval, and (iv) ribbon. In 75% of the teeth, the canal shapes varied from one level to the next. The more coronally the root-end resection was made, the more elongated the canal tended to become.