Effect of Thermal Cycling Aging on the Surface Microhardness and Roughness of Resin-Infiltrated Enamel Lesions

With the widespread use of resin infiltration, its properties have drawn increasing attention. The objective of this study was to investigate the effect of resin infiltration on the surface microhardness and roughness of enamel lesions after thermal cycling aging. Tooth blocks were made from extracted premolars and placed into a control group, resin-infiltrated group or demineralized group. Before and after the aging procedure, the surface microhardness and surface roughness was measured. Before the aging procedure, the surface microhardness of the control group, resin-infiltrated group and demineralized group was 302.14 (±9.77) HV, 146.62 (±8.22) HV, and 28.85 (±2.21) HV ( p 0.001), respectively. After the aging procedure, the surface microhardness of the control group, resin-infiltrated group and demineralized group decreased by 9.42%, 16.59%, and 20.75% ( p 0.001), respectively. Before the aging procedure, the surface roughness of the control group, resin-infiltrated group and demineralized group was 0.29 (±0.04) μ m, 0.32 (±0.04) μ m, and 0.39 (±0.07) μ m ( p = 0.009), respectively. After the aging procedure, the surface roughness of the control group, resin-infiltrated group and demineralized group increased by 9.85%, 8.31%, and 17.37% ( p = 0.634), respectively. Resin infiltration can improve the surface microhardness and surface roughness of demineralized teeth in an artificial enamel caries model. The treatment also shows good aging resistance after thermal cycling. The infiltrant resin provided a suitable material for early enamel caries.