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

By Burleson A, Nusstein J, Reader A, Beck M

Date: 01/2007
Journal: JOE


Purpose: to histologically compare biofilm/necrotic debris debridement efficacy of a hand/rotary instrumentation technique to a hand/rotary instrumentation plus one minute ultra- sound technique in the mesial roots of human, necrotic mandibular molars.

  • N= 48 human mandibular molars
  • Materials/Methods:

  • 48 human mandibular molars planned for extraction, divided into 3 groups: G1 hand/rotary instrumentation (n=20), G2: hand/rotary/ 1 min ultrasonic irrigation per canal (n=20), G3: control (n=8)
  • G1 and G2 step-back instrumentation with K-type hand files and rotary ProFile GT, 6.0% sodium hypochlorite for irrigation, final apical preparation size #30 hand file
  • After cleaning and shaping was completed, G1 irrigated with 15 ml of 6.0% sodium hypochlorite.
  • G2 received ultrasonic irrigation using “MiniEndo ultrasonic unit” set at maximum power for 1 min at rate of 15 ml/min
  • Following extraction, histologic preparation were evaluated for percentage of biofilm/necrotic debris removal.

Most highlighted Results: 

Mean percent canal and isthmus cleanliness values were significantly higher for hand/rotary/ultrasnic technique at all

levels evaluated. (table 1)

Clinical significance:

the 1-minute use of ultrasonically activated irrigation, following hand/rotary root canal cleaning and shaping, has been shown to improve canal and isthmus cleanliness in terms of necrotic debris/biofilm removal. Empirically this should improve the clinical outcomes of these cases.