Peer-Reviewed Journal Details
Mandatory Fields
Lucey, S; Lynch, CD; Ray, NJ; Burke, FM; Hannigan, A;
Journal of Oral Rehabilitation
Effect of pre-heating on the viscosity and microhardness of a resin composite
Optional Fields

P>The effect of pre-heating resin composite on pre-cured viscosity and post-cured surface hardness was evaluated. Groups of uncured specimens were heated to 60 degrees C and compared with control groups (24 degrees C) with respect to viscosity and surface hardness. Mean (SD) viscosities of the pre-heated specimens (n=15) were in the range of 285 (13)-377 (11) (Pa) compared with 642 (35)-800 (23) (Pa) at ambient temperature. There was a statistically significant difference between the two groups (P < 0 center dot 001). Mean (SD) Vickers microhardness (VHN) of the pre-heated group (n=15) was 68 center dot 6 (2 center dot 3) for the top surface and 68 center dot 7 (1 center dot 8) for the bottom surface measured at 24 h post curing (specimen thickness=1 center dot 5 mm). The corresponding values for the room temperature group were 60 center dot 6 (1 center dot 4) and 59 center dot 0 (3 center dot 5). There was a statistically significant difference between corresponding measurements taken at the top and bottom for the pre-heated and room temperature groups (P < 0 center dot 001). There was no significant difference between top and bottom measurements within each group. Pre-heating resin composite reduces its pre-cured viscosity and enhances its subsequent surface hardness. These effects may translate as easier placement together with an increased degree of polymerization and depth-of-cure.

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