Resin infiltration of deproteinised natural occlusal subsurface lesions improves initial quality of fissure sealing

The aim of this ex vivo study was to evaluate the infiltration capability and rate of microleakage of a low-viscous resin infiltrantcombined with a flowable composite resin （RI/CR） when used with deproteinised and etched occlusal subsurface lesions（International Caries Detection and Assessment System code 2）. This combined treatment procedure was compared with theexclusive use of flowable composite resin （CR） for fissure sealing. Twenty premolars and 20 molars revealing non-cavitatedocclusal carious lesions were randomly divided into two groups and were meticulously cleaned and deproteinised using NaOCI（2%）. After etching with HCI （15%）, 10 premolar and 10 molar lesions were infiltrated （Icon/DMG; rhodamine B isothiocyanate（RITC）-Iabelled） followed by fissure sealing （G-zenial FIo/GC; experimental group, RI/CR）. In the control group （CR）, the cariousfissures were only sealed. Specimens were cut perpendicular to the occlusal surface and through the area of the highestdemineralisation （DIAGNOdent pen, KaVo）. Using confocal laser-scanning microscopy, the specimens were assessed withregard to the percentage of caries infiltration, marginal adaption and internal integrity. Within the CR group, the cariouslesions were not infiltrated. Both premolar （57.9%± 23.1%） and molar lesions （35.3% ± 22.1%） of the RI/CR group wereuniformly infiltrated to a substantial extent, albeit with significant differences （P= 0.034）. Moreover, microleakage （n= 1） andthe occurrence of voids （n= 2） were reduced in the RI/CR group compared with the CR group （5 and 17 specimens,respectively）. The RI/CR approach increases the initial quality of fissure sealing and is recommended for the clinical controlof occlusal caries.