title: Microscopic view of scaling influence on the root, using different power and time settings.
abstract: OBJECTIVE
  The aim of this paper was to identify the appropriate power setting and operation time required to achieve optimal efficiency in calculus debridement while preventing excessive cementum loss.
  
  
  METHODS
  The study included 30 extracted molars with heavy deposits of calculus, visible to the the naked eye. Experimental areas (3 × 4 mm) were delineated below the cementoenamel junction. The teeth were cut cross-sectionally and randomly allocated into three groups: low, medium, and high power settings. A magnetostrictive ultrasonic scaler with Dentsply slimline plain insert was used with light force at 0-degree tip angulation for a 10 second interval. Before and after treatment, the samples were visualized using digital stereo microscopy at 100× magnification.
  
  
  RESULTS
  Mean time required for dental calculus removal was 70, 50, and 30 seconds for low, medium, and high power settings, respectively. Root calculus removal rates for low, medium, and high power settings were 4.5, 6.7, and 8.2 μm/s, respectively (P = .0045, P < .01). Mean time required for dental cementum removal was 30, 30, and 20 seconds for low, medium, and high power settings, respectively. Cementum removal rates for low, medium, and high power settings were 1.7, 2.2, and 3.3 μm/s, respectively (P = .0127, P < .05).
  
  
  CONCLUSIONS
  The most efficient dental calculus removal occurred within the first 30 seconds using a high power setting with light force at 0-degree tip angulation, which was recommended for roots with heavy calculus. Later on, to minimize cementum loss, the low power setting should be used for less than 30 seconds to balance between rapid calculus removal and a potential risk of cementum loss resulting in dental sensitivity. Ultrasonic scaling using the high power setting in the first 30 seconds, followed by continuous scaling for less than 30 seconds, using the low power setting, is recommended for roots with heavy calculus.
authors.forename: Hung-Chieh
authors.initials: HC
authors.lastname: Chien
authors.forename: Dong-Qing
authors.initials: DQ
authors.lastname: Ye
mesh_terms: D003728:Dental Calculus / Q000628:therapy*; D012534:Dental Scaling / Q000379:methods*; D006801:Humans; D066298:In Vitro Techniques; D008963:Molar; D011897:Random Allocation; D013499:Surface Properties; D013997:Time Factors; D014092:Tooth Root / Q000648:ultrastructure*