title: The effect of oscillation and low seating forces on pulpward pressure transmission and seating during crown cementation: a laboratory study.
abstract: OBJECTIVE
  This study investigated the effects of low seating force (5 N) with and without oscillation on pulpward pressure transmission during crown cementation.
  
  
  METHODS
  Thirty human premolars received standardized complete-crown preparations. They were randomly allocated into three experimental groups of ten: group 1 = 100-N static load; group 2 = 5-N static load; and group 3 = 5-N load with oscillation. Crowns were constructed of base-metal alloy and attached to a purpose-built loading device. Pulpal pressures were recorded using a 0- to 104-kPa pressure transducer that was connected via the sectioned root of the premolar to the pulp chamber, which was perfused with saline driven by nitrogen gas at 83 kPa until a steady rate was achieved. The crowns were cemented using zinc phosphate cement, and postcementation elevations were measured with a linear variable differential transformer. An amalgam condenser provided oscillation for 1 minute.
  
  
  RESULTS
  The pulpal pressures were: group 1 = 455 Pa; group 2 = 26 Pa; and group 3 = 76 Pa. The postcementation crown elevations were: group 1 = -48 microm; group 2 = 362 microm; and group 3 = 26 microm.
  
  
  CONCLUSIONS
  Acceptable crown seating can be obtained using low force (5 N) combined with oscillation, and lower pressure pulses are generated compared to using high force (100 N) alone.
authors.affiliation: The University of Melbourne, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Humplik
authors.forename: P R
authors.initials: PR
authors.lastname: Wilson
mesh_terms: D001641:Bicuspid; D002484:Cementation; D003442:Crowns; D003722:Dental Alloys; D003782:Dental Pulp / Q000503:physiopathology*; D003786:Dental Pulp Cavity / Q000503:physiopathology; D006801:Humans; D009991:Oscillometry; D011312:Pressure; D012212:Rheology; D012815:Signal Processing, Computer-Assisted; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013997:Time Factors; D014160:Transducers, Pressure; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D003722:Dental Alloys; D015036:Zinc Phosphate Cement