title: In vitro assessment of temperature change in the pulp chamber during cavity preparation.
abstract: BACKGROUND
  Tooth preparation with a high-speed handpiece may cause thermal harm to the dental pulp.
  
  
  OBJECTIVE
  This in vitro study evaluated the temperature changes in the pulp chamber during 4 different tooth preparation techniques and the effects of 3 different levels of water cooling.
  
  
  METHODS
  The tip of a thermocouple was positioned in the center of the pulp chamber of 120 extracted Shuman premolar teeth. Four different tooth preparation techniques were compared: (1) Low air pressure plus low load (LA/LL), (2) low air pressure plus high load (LA/HL), (3) high air pressure plus low load (HA/LL), and (4) high air pressure plus high load (HA/HL) in combination with 3 different water cooling rates. Control specimens were not water cooled; low water cooling consisted of 15 mL/min, and high water cooling consisted of 40 mL/min. Twelve different groups were established (n=10). An increase of 5.5 degrees C was regarded as critical value for pulpal health. The results were analyzed with a 3-factor ANOVA and Bonferroni adjusted Mann Whitney U test (alpha=.004).
  
  
  RESULTS
  For all techniques without water cooling (LA/LL/0, LA/HL/0, HA/LL/0, and HA/HL/0), the average temperature rise within the pulpal chamber exceeded 5.5 degrees C during cavity preparation (7.1 degrees C; 8.9 degrees C; 11.4 degrees C, and 19.7 degrees C, respectively). When low water cooling was used with high air pressure and high load technique (HA/HL/15), the average temperature rise exceeded 5.5 degrees C limit (5.9 degrees C). However, when high water cooling (LA/LL/40, LA/HL/40, HA/LL/40, and HA/HL/40) was utilized, the critical 5.5 degrees C value was not reached with any air pressure or load (3.1 degrees C, 2.8 degrees C, 2.2 degrees C, and -1.8 degrees C, respectively).
  
  
  CONCLUSIONS
  Within the limitations of this in vitro study, the results indicate that reducing the amount of water cooling or increasing air pressure and load during cavity preparation increased the temperature of the pulp chamber in extracted teeth.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, University of Selcuk, Konya, Turkey. bozturk@selcuk.edu.tr
authors.forename: Bora
authors.initials: B
authors.lastname: Oztürk
authors.forename: Aslihan
authors.initials: A
authors.lastname: Uşümez
authors.forename: A Nilgun
authors.initials: AN
authors.lastname: Oztürk
authors.forename: Füsun
authors.initials: F
authors.lastname: Ozer
mesh_terms: D000399:Air Pressure; D000704:Analysis of Variance; D001831:Body Temperature / Q000502:physiology*; D003737:Dental Cavity Preparation / Q000295:instrumentation / Q000379:methods*; D003754:Dental High-Speed Equipment; D003782:Dental Pulp / Q000503:physiopathology*; D018130:Diamond; D006801:Humans; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013821:Thermometers; D014867:Water
chemical_list: D014867:Water; D018130:Diamond