title: [Influence of intra-pulpal temperature when using femtosecond laser in specific parameters to prepare cavities in tooth enamel: an in vitro study].
abstract: OBJECTIVE
  To take the Real-time measurement of the intra-pulpal temperature (IPT) when using femtosecond laser in specific parameters to prepare cavities in tooth enamel in vitro, and to preliminarily evaluate the effect of air cooling.
  
  
  METHODS
  All pulp champers of extracted human teeth (premolars and molars) were exposed by roots amputated and pulp scraped out. All chambers were tightly filled with copper powder, and thermocouple was inserted into the center of the powder stack. The bottom of the chamber was sealed with insulating tape. Thermocouple wire was fixed at the same time. The 2.25 mm×2.25 mm square cavities were prepared using femtosecond laser in the enamel with the average scan speed of 0.4 mm/s. The real-time IPT change was measured with thermocouple digital thermometer. Air cooling was added to the procedure once the temperature increased to reach a balance.
  
  
  RESULTS
  The IPT rising was defined as ΔT . Before the usage of air cooling, the maximum of the ΔT value of the sample premolar was 12.3 °C. After using air cooling, the IPT decreased and ΔT value became 3.0 °C . The maximum of ΔT of the sample molar before using air cooling was 1.8 °C , and decreased to -0.1 °C after it.
  
  
  CONCLUSIONS
  When preparing a cavity whose average depth is about 250 μm by femtosecond laser system in specific parameters, the IPT rises while the depth increass, but it could be controlled effectively by air cooling.
authors.affiliation: Center of Digital Dentistry, National Engineering Laboratory for Digital and Material Technology of Stomatology, Peking University School and Hospital of Stomatology Beijing 100081, China.
authors.forename: Yu-chun
authors.initials: YC
authors.lastname: Sun
authors.forename: Anatoliy
authors.initials: A
authors.lastname: Vorobyev
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Chun-lei
authors.initials: CL
authors.lastname: Guo
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
mesh_terms: D003737:Dental Cavity Preparation / Q000295:instrumentation / Q000379:methods*; D003743:Dental Enamel / Q000528:radiation effects*; D003754:Dental High-Speed Equipment; D003782:Dental Pulp / Q000503:physiopathology*; D018130:Diamond; D006358:Hot Temperature; D006801:Humans; D053844:Lasers, Solid-State / Q000009:adverse effects*; D008963:Molar
chemical_list: D018130:Diamond