A methodology for evaluation of root canal instrumentation

A methodology for evaluation of root canal instrumentation

0099-2399187113050243/$02.00/0 JOURNALOF ENDOOONlrlCS Copyright 9 1987 by The ~ Printed in U.S.A. VOL. 13, NO. 5, MAY 1987 Association of EnGkx:lont...

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0099-2399187113050243/$02.00/0 JOURNALOF ENDOOONlrlCS Copyright 9 1987 by The ~

Printed in U.S.A. VOL. 13, NO. 5, MAY 1987

Association of EnGkx:lonttsts

RESEARCH AID A Methodology for Evaluation of Root Canal Instrumentation Clovis Monteiro Bramante, DDS, Alceu Berbert, DDS, and Roberto Pinheiro Borges, DDS

the root to be inserted into the colorless resin block and at the same time to be placed in the plaster stone, which served as a removable muffle (Fig. 1B). After the muffle was opened, the resin block (with the root) was removed and sectioned using a hard tissue microtome (BromwelI-Motor Apliance, WRP) at three levels: cervical, middle, and apical (Fig. 2). These sectioned portions were mounted onto a glass slide and photographs were taken in order to obtain transparencies. This procedure was done with the same focal length for all sections (Fig. 3). Next, the transverse sections were mounted again in their original position, placed into the muffle, and the root canals were instrumented. The last step included removing the sections. They were then mounted on the glass slide and photographs were again taken in order to obtain transparencies as described before (Fig. 4). The transparency of each section, before the instrumentation, was projected with x l 0 amplification over a white sheet of paper, so the profile of the root and canals were delineated. In the same way, these pro-

We present a methodology for comparing root canal anatomy before and after root canal instrumentation. The root canal anatomy prior to instrumentation serves as the control. This method enables one to obtain information for statistical analysis.

The evaluation of the efficiency of root canal instrumentation has been analyzed using the common optical microscope (1-5), the scanning electron microscope (6-9), radiographic examinations (10-12), photographic studies (A. Foyatier, personal communication), root canal models (13-16), and the computer (17). However, the majority of these studies have been performed after the root canal has been instrumented, when the original pattern of the model was changed and therefore a comparative analysis was not allowed. The intent of this article was to present an objective method for studying the anatomical morphology of root canals, before and after instrumentation, in order to make accurate comparison. METHODOLOGY

The root of the selected tooth used in this study was inserted into a colorless acrylic-resin, chemically activated, in order to obtain a small pyramidal block. After the resin polymerized, by means of a carburundum disc, transverse grooves were made over the margins of the block, according to the proximal surfaces of the tooth (Fig. 1A). The resin block was then placed horizontally in a special wooden tray and plaster stone was poured into the tray until half of the resin block was covered. While the dental plaster was setting, grooves were made over its superficial area and guides were obtained. After the dental stone had set and its surface had been lubricated, new plaster stone was flowed over the set resin and dental plaster together in order to complete the embedding (Fig. 1B). This procedure allowed

FIG 1. The tooth was embedded in an acrylic-resin block with grooves cut as guides (,4) and then was covered by a plaster stone removable muffle (B). 243

Bramante et al.

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FIG 4. Transverse section photographs of the same specimens shown in Fv:j. 3, but now, after root canal instrumentation.

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FIG 3. Transverse section photographs o f the canncal, middle, and apical portions before root canal instrumentation.

cedures were repeated with the transparency of sections made after instrumentation, on the same sheet of the paper with the profiles superposed (Fig. 5). To measure the areas of the profiles, a Planimeter (Compensating Polar Planimeter, Type K-27; Koirumi, Japan) was used and each unit of measurement was changed to square milimeters. This procedure provided the original area of the root canal (anatomical area) and the instrumented root canal (operative area) so that the differences between both areas could be compared. This is an important procedure because it is essential to record the patterns of instrumentation (mesial, distal, buccal, or palatal, which tends to straighten the curvature of the original canal) on the cervical, middle, or apical portions. The results obtained may then be tabulated for statistical analysis.

FIG 5. Profile drawing of root canals, before and after (arrows) root canal instrumentation, in the cervical, middle, and apical portions.

D I S C U S S I O N

Although several methodologies may be used to analyze instrumentation effects on root canals, a reliable method is necessary in order to verify the root canals, before and after instrumentation. This may be possible by the method described here. It is a very simple method and may be easily learned, enabling qualitative and statistical studies of root canal instrumentation. We mank Dr. Mario Leonardo, professor o1 Endodontics, School of Dentistry of Araraquara, University of Sao Paulo State lor English translation9 Drs. Bramante and Berbert are professors of endodootcs, School of Dentistry of Bauru, University of Sao Paulo-Bauru, Sao Paul, Brazil. Dr. Borges is professor of endodontics, School of Dentistry of Fortaleza, Cearb, Brazil.

Root Canal Instrumentation

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