Abstract
Biomechanical instrumentation of the root canal is one of the most important phases of root canal treatment. There are several articles on scanning electron microscopic study of the root canal walls of permanent teeth after endodontic procedures. However, there are no reports on deciduous teeth.
In this study, the effectiveness of the instrumentation and irrigation of the root canal of deciduous teeth was evaluated by means of scanning electron microscopy.
The root canals of nine recently extracted and single rooted deciduous teeth were prepared. Each of the root canals was instrumented in vitro according to accepted clinical procedures through the crown of the tooth with K-type files (Zipperer), H-type files (Zipperer), or Diamond files (Kerr). The mechanical instrumentation was always followed by the combination irrigating procedure using sodium hypochlorite and hydrogen peroxide by means of a syringe. Final irrigation was performed with distilled water. On completion of instrumentation and irrigation, horizontal and longitudinal cuts were made on the cervical line, half length of the root, and the labial and lingual surfaces. Each root was split into four sections (crown side-mesial section, crown side-distal section, apex side-mesial section and apex side-distal section). The hemisections of the crown side and the apex side were not treated with an ultrasonic cleaner. The other sections were rinsed with an ultrasonic cleaner.
Each section was examined by scanning electron microscopy.
The results obtained were as follows
1. The standard instrumentation techniques produced a canal wall that had uninstrumented areas.
2. The canal wall was smeared with dentin mud. Dentin tubules were not observed due to the smeared layer. The canal wall of apex side was smeared with dentin mud and packed with debris.
3. The irrigating procedure commonly used in endodontic practice was not effective in removing the smeared layer. Ultrasonic cleaning also was not effective.
4. Among the use of K-type files, H-type files and Diamond files, no different effects were observed.
