Temperature rise on dentin caused by temporary crown and fixed partial denture materials: influencing factors.
OBJECTIVE
Temporary crowns and fixed partial denture materials (t-c&b) generate exothermic heat during polymerization. The amount of temperature, reaching the pulp chamber, is dependent on the residual thickness of the prepared dentin as well as the volume of the t-c&b used. Hence, the aim of this study was to investigate the influence of both factors on the temperature rise at the pulpal dentin surface as well as in the bulk of the t-c&b during polymerization.


METHODS
Four t-c&bs (Luxatemp AM Plus, Protemp 3 Garant, Structur Premium, Trim) were used to fabricate flat cylindrical specimens (∅ 15.5mm) of different thicknesses (1, 2 and 4mm) using an over-impression placed on top of dentin discs (thickness 0.5, 1 and 2mm). Temperature was recorded at the pulpal dentin surface as well as inside the t-c&b (n=6). Data was subjected to parametric statistics (α=0.05).


RESULTS
Peak temperatures inside the t-c&b varied between 37.0°C and 51.9°C and at the pulpal dentin side between 37.0°C and 50.6°C. The maximum temperatures registered depended significantly on the thickness of the dentin disc and t-c&b, respectively (ANOVA p<0.05). Peak temperatures were reached 2-3 min after start of mixing (dimethacrylates) and 6 min (mono-methacrylate), respectively, whereas Trim exhibited significantly higher peak temperatures (p<0.05).


CONCLUSIONS
At 4mm layer thickness of the t-c&b, temperature rise may become critical if the material is not cooled properly. Composite-based t-c&bs showed significant lower curing temperatures than Trim and should therefore be preferred in daily practice.
Seelbach
Paul
P
Department of Prosthetic Dentistry, Justus-Liebig-University, D-35392 Giessen, Germany.
Finger
Werner J
WJ
Ferger
Paul
P
Balkenhol
Markus
M
D000704:Analysis of Variance; D001831:Body Temperature; D003442:Crowns; D003794:Dental Restoration, Temporary; D003804:Dentin / Q000033:anatomy & histology; D003830:Denture, Partial, Fixed; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates; D008963:Molar; D058105:Polymerization
D008689:Methacrylates