Intrapulpal temperature variation during bleaching with various activation mechanisms.
OBJECTIVE
The aim of this study was to evaluate the intrapulpal temperature variation after bleaching treatment with 35% hydrogen peroxide using different sources of activation.


METHODS
Twenty-four human teeth were sectioned in the mesiodistal direction providing 48 specimens, and were divided into 4 groups (n=12): (G1) Control - Bleaching gel without light activation, (G2) Bleaching gel + halogen light, (G3) Bleaching gel + LED, (G4) Bleaching gel + Nd:YAG Laser. The temperatures were recorded using a digital thermometer at 4 time points: before bleaching gel application, 1 min after bleaching gel application, during activation of the bleaching gel, and after the bleaching agent turned from a dark-red into a clear gel. Data were analyzed statistically by the Dunnet's test, ANOVA and Tukey's test (a=0.05).


RESULTS
The mean intrapulpal temperature values ( degrees C) in the groups were: G1: 0.617 +/- 0.41; G2: 1.800 +/- 0.68; G3: 0.975 +/- 0.51; and G4: 4.325 +/- 1.09. The mean maximum temperature variation (MTV) values were: 1.5 degrees C (G1), 2.9 degrees C (G2), 1.7 degrees C (G3) and 6.9 degrees C (G4). When comparing the experimental groups to the control group, G3 was not statistically different from G1 (p>0.05), but G2 and G4 presented significantly higher (p<0.05) intrapulpal temperatures and MTV. The three experimental groups differed significantly (p<0.05) from each other.


CONCLUSIONS
The Nd:YAG laser was the activation method that presented the highest values of intrapulpal temperature variation when compared with LED and halogen light. The group activated by LED light presented the lowest values of temperature variation, which were similar to that of the control group.
Michida
Sílvia Masae de Araujo
SM
Department of Dental Materials and Prosthodontics, São Paulo State University, São José dos Campos, SP, Brazil. silviamasae@yahoo.com
Passos
Sheila Pestana
SP
Marimoto
Angela Regina Kimie
AR
Garakis
Márcia Carneiro Valera
MC
de Araújo
Maria Amélia Máximo
MA
D001831:Body Temperature / Q000187:drug effects*; D003782:Dental Pulp / Q000187:drug effects*; D005782:Gels; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000528:radiation effects / Q000627:therapeutic use*; D053844:Lasers, Solid-State / Q000627:therapeutic use; D008027:Light; D008029:Lighting / Q000295:instrumentation; D008422:Materials Testing; D016877:Oxidants / Q000008:administration & dosage / Q000528:radiation effects / Q000627:therapeutic use*; D013821:Thermometers; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*
D005782:Gels; D016877:Oxidants; D006861:Hydrogen Peroxide