Effect of the gap width around a restoration on the formation of artificial caries lesion

WANG Wan-shan; ZHAO Xin-yi

doi:10.15956/j.cnki.chin.j.conserv.dent.2015.04.012

Abstract：AIM:To evaluate the effect of the gap width around a restoration on the formation of artificial caries lesion.METHODS:Each of bovine enamel blocks was invested into a metal ring and then was cut longitudinal-ly into 2 equal portions.One portion was inserted into the ring again and the cut surface of the enamel block was ad-hered with a plastic space sheet,with a thickness(μm)of 25,50,100,190 and 270 respectively,followed by inser-tion of a restorative material (Charisma and Fuji Ⅶ respectively)into the residual space of the ring.All restoration specimens were immersed in water for 7 d and then in demineralization solution for 72 h,followed by filling each gap with a light curing sealant resin.Each specimen was cut vertically through the gap to obtain slices of 150 μm thick for the observation under a polarized light microscope and the depths of outer lesion and wall lesion of each specimen were measured using image analysis software.RESULTS:All specimens presented a deeper outer lesion than wall lesion (P<0.05)and Charisma group presented deeper outer lesion than FujiⅦgroup(P<0.05).The depth of wall lesion increased with the increase of the gap width within 100 μm and the Charisma group showed deeper wall lesion than FujiⅦ group(P<0.05 )when the gap width was within 50 ~100 μm.CONCLUSION:The artificial secondary caries model with controlled marginal gap can present obvious out lesion and wall lesion and present the difference of fluoride-releasing materials and non-fluoride-releasing materials in preventing wall lesion.