Efecto del precalentamiento en la microdureza superficial de seis resinas compuestas

Background:Preheating resins has been shown to improve physical properties such as surface microhardness. Some low-cost composite resins have not been well studied and preheating could improve their properties. Objective:to evaluate if preheating increases the surface microhardness of 6 composite resins and if the microhardness of the preheated low-cost ones equals that of the other resins Method: In this In vitro experimental investigation, 6 resins were used, EnaHri®UE2 and UD2 (Micerium, Genoa Italy) as control, Z350TMand Z250TM(3M ESPE, Minnesota United States) conventionally used composites and LUNA ® and ROK®(SDI, Victoria Australia) as low-cost resins. Specimens without preheating (sp) and preheating at 39°C (p) were created for each resin. It was polymerized according to the manufacturers' instructions. Three measurements were made per sample using a microhardness tester applying a 300 g load for 10 seconds. Results: Resin-enamel microhardness: LUNA ® sp69.93 HV (95% CI 62.02-77.85), Z350TMsp89.9 HV (95% CI 80.56-99.23), LUNA ®
p70.05 HV (95% CI 62.97-77.12), Z350TMp 87.47 HV (CI 95% 78.71-96.23). The microhardness of resins-dentin: ROK®sp85.16 HV (95% CI 69.91-100.4), Z250TMsp 95.99 HV (95% CI 74.8-117.2), ROK® p92.19 HV (95% CI 80.83-103.6), Z250TMp 104.7 HV (95% CI 97.76-111.6). Preheating did not significantly increase microhardness except for control resins. ROK ® spis equivalent to Z250TMsp (p 0.2825). Conclusion:Preheating does not increase the surface microhardness of the composite resins analyzed. The microhardness of ROK ® spresin is equivalent to Z350TM sp.