The In Vivo Evaluation of Hand/Rotary/Ultrasound Instrumentation in Necrotic, Human Mandibular Molars

doi:10.1016/j.joen.2007.04.015

Journal of Endodontics

Volume 33, Issue 7, July 2007, Pages 782-787

https://doi.org/10.1016/j.joen.2007.04.015 Get rights and content

Abstract

This in vivo, prospective, randomized, single-blinded study histologically compared biofilm/necrotic debridement efficiency of a hand/rotary technique versus a hand/rotary/1 min ultrasound technique in the mesial roots of necrotic, human mandibular molars. The hand/rotary group consisted of 20 mesial roots. The hand/rotary/ultrasound group consisted of 20 mesial roots prepared with the same hand/rotary technique followed by 1 min of ultrasonic irrigation, per canal, utilizing an ultrasonic needle in a MiniEndo^™ unit. Following extraction, histologic preparation and staining, 0.2 μm cross-sections from the 1- to 3-mm apical levels were evaluated for percentage of biofilm/necrotic debris removal. Cleanliness results at the 1-, 2- and 3-mm levels for the hand/rotary and hand/rotary/ultrasound techniques, respectively, were: Canals, 80% versus 95%, 92% versus 99%, and 95% versus 100%; Isthmuses, 33% versus 83%, 31% versus 86%, 45% versus 91%. Statistical analysis revealed mean percent canal and isthmus cleanliness values to be significantly higher for hand/rotary/ultrasound technique at all levels evaluated.

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Materials and Methods

Forty-eight adult subjects participated in this study. The Human Subjects Review Committee of The Ohio State University approved the study, and written informed consent was obtained from each subject. The subjects were in good health as determined by written and oral questioning.

Clinical examination by thermal (Green Endo-Ice®, Hygenic Corp., Akron, OH), electric pulp (Kerr Vitality Scanner, Kerr Dental, West Collins Orange, CA), and percussion testing indicated all mandibular molars had an

Results

A comparison of canal and isthmus cleanliness is shown in the Table 1. Fig. 2 shows examples of canal preparation for the hand/rotary group and hand/rotary/ultrasound group.

For canal cleanliness, there were significant differences at all eleven apical levels between the two techniques (Table 1). Isthmus cleanliness values were significantly different between the two treatment groups at all eleven levels examined (Table).

The uninstrumented control teeth (Group 3) showed mean canal cleanliness

Discussion

The mean canal cleanliness values (Table 1) for the hand/rotary instrumentation group are better as compared to those reported by other authors utilizing step-back preparation method (2, 3, 4) and similar to those reported by Gutarts et al. (12). These studies all utilized vital teeth and therefore more tissue had to be removed as compared to the necrotic root canals (Group 3 – Table) used in this study. The addition of 1-minute of ultrasonically activated NaOCl significantly improved the

Acknowledgment

This study was supported by research funding from the Endodontic Graduate Students’ Research Fund, The Ohio State University.

The ultrasonic irrigating device has been patented and is owned by The Ohio State University. Dr. Nusstein is the inventor with potential financial interest in this device.