THE EFFECT OF CERTAIN PREPARATION TECHNIQUES ON THE SHAPE, CLEANLINESS AND QUALITY OF APICAL SEAL OF CURVED ROOTS (AN INVITRO STUDY)

Abstract

The present study was canied out to evaluate and compare the effect of four instrumentation techniques [The Step-Back, The Step-Down, The Balanced-Force and The Circumferential fi ling], on the final shape of the prepared root canals, the cleanliness of the prepared root canals and the »Y quality of apical seal produced with each technique. 60 mandibular mesial roots of lower molars were classified into three main groups: (group I) of 20 mesial roots were used for evaluation of shape, (group II) of 20 mesial roots were used for evaluation of cleanliness and (group lll) of 20 mesial roots were used for evaluation of apical seal. Then each main group was subdivided into four subgroups (5 roots each with

IO root canals) as follow:

4 l. The first four subgroups of the main three groups were prepared using the

Step-Back technique .

2. The second four subgroups of the three main groups were prepared using the Step-Down technique . 3. The third four subgroups of the main three groups were prepared using the

Balanced-Force technique.

4. The fourth four subgroups of the main three groups were prepared using the Circumferential filing technique. For evaluation of shape, three cross sections were made at the cervical level, the middle level and the apical level, for each mesial root and evaluated by the stereomicroscope at 37 X magnification to determine the cross section shape of each prepared root canal whether round, oval or irregular in shape. Also the Computed Dental Radiography was used for more confirmation of the results of shape.