Endodontology
Evaluation of different methods for the root-end cavity preparation

https://doi.org/10.1016/j.tripleo.2004.02.062Get rights and content

Abstract

Objective

The dentinal walls of root-end cavities were examined for the presence of cracks and debris in correlation with the area of the root surfaces that remained after the resection.

Study design

One hundred extracted single-rooted teeth were endodontically treated, mounted in acrylic resin blocks, and the apical 2 mm of the root-apex was resected. According to the resected root surface area the teeth were divided into 2 groups having large (>2 mm2) or small (<2 mm2) surface area. For retrograde cavity preparation 4 devices were used: slow-speed handpiece, diamond coated stainless steel ultrasonic tip, smooth stainless steel ultrasonic tips, and sonic diamond-coated tips. Teeth were examined under a videomicroscope for the presence of fractures, dentin chips, and gutta-percha remnants on cavity walls. Preparation time was also recorded.

Results

Preparation with smooth stainless steel ultrasonic tips produced few intradentin cracks. Dentin debris was more frequently seen in rotary preparations whereas gutta-percha remnants were seen mainly at ultrasonically prepared teeth.

Conclusions

Sonic and ultrasonic devices produced cleaner, well-centered, and more conservative root-end cavities than the rotary instrumentation. Cracks do not correlate directly with the surface area of the root-end surfaces but rather with the type of retrotip used to prepare the root-end cavity.

Section snippets

Specimen selection

One hundred recently extracted human teeth, 43 canines of both jaws and 57 incisors of the lower jaw, having a straight single root with fully developed apices were used in this study. All teeth were immersed in a 3% NaOCl solution for 15 minutes immediately after extraction. Afterwards, remaining periapical and periodontal tissues were removed with curettes and stored in a saline solution at room temperature.

Specimen preparation

An evaluation of the existence of fractures or dentinal cracks in roots due to the

Crack formation

Close inspection of the resected root surfaces immediately after cutting the root apex did not reveal any crack formation. After the root-end cavity preparation there were no detectable complete cracks involving dentine and cementum. However, small intradentinal cracks (incomplete cracks) were detected in 7% of the small roots of group A, 20% of the large and 21% of the small roots in group C (Table I).

Debris in the cavities

All methods used produced dentine chips on the walls of cavities However, the amount of

Discussion

Recent studies have shown that an ideal root-end cavity preparation is very difficult to achieve with the use of burs on micro-motor, and that better results are obtained with the use of ultrasonic tips.1., 5., 7. Furthermore, an increased cavity depth can be achieved with ultrasonic tips, a significant factor for controlling apical leakage.16 Thus, an increase of the success rate of endodontic surgery procedure may be expected since isthmuses, fins, and other significant anatomical

Conclusion

Based on the conditions of this study, the following conclusions can be drawn:

The area of the root-end dentin surfaces after resection does not influence the crack formation during the preparation of the root-end cavity with rotary, sonic, and ultrasonic instruments.

Cracks were produced at the root-end face, mainly when the smooth stainless steel ultrasonic retrotips were used.

Dentinal chips were found in all experimental groups with the highest rate in the rotary instrument group.

Gutta-percha

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This investigation was supported by a grant from the secretariat of the Research Committee of the National and Kapodistrian University of Athens.

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