Influence of the degree of dentine mineralization on pulp chamber temperature increase during resin-based composite (RBC) light-activation
Received 20 October 2009; received in revised form 21 December 2009; accepted 22 December 2009. published online 31 December 2009.
Abstract
Objectives
To analyse the influence of the degree of dentine mineralization on the pulp chamber temperature increase during composite light-activation.
Methods
Dentine discs (2mm thick) obtained from recently extracted teeth or those with extensive dentine sclerosis were analysed by FT-IR spectrometry in order to choose the two discs with the greatest difference in the degree of mineralization. A model tooth was set up with the dentine discs between a molar with the pulp chamber exposed and a crown with a standardized class II cavity. A K-type thermocouple was introduced into the molar root until it came into contact with the dentine discs and the cavity was filled with P60 resin composite. The temperature rise was measured for 120s after light-activation began: Standard (S) 600mW/cm2/40s; Ramp (R) 0→800mW/cm2/10s+800mW/cm2/10s; Boost (B) 850mW/cm2/10s and LED (L) 1.300mW/cm2/40s (n=10). The same protocol was repeated after grinding the dentine discs to 1.0 and 0.5mm thickness.
Results
The temperature increase was significantly higher in dentine with high degree of mineralization (p<0.05). With respect to the dentine thickness, the following result was found: 2mm<1mm<0.5mm (p<0.05). The light-activation mode also presented significant difference as follows: S>R=L>B (p<0.05).
Conclusions
The higher the degree of dentine mineralization the greater the increase in pulp chamber temperature. The temperature increase was influenced by the light-polymerization mode and dentine thickness.
ABSTRACT