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 infiltrant combined 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 the exclusive use of flowable composite resin (CR) for fissure sealing. Twenty premolars and 20 molars revealing non-cavitated occlusal carious lesions were randomly divided into two groups and were meticulously cleaned and deproteinised using NaOCl (2%). After etching with HCl (15%), 10 premolar and 10 molar lesions were infiltrated (Icon/DMG; rhodamine B isothiocyanate (RITC)-labelled) followed by fissure sealing (G-ænial Flo/GC; experimental group, RI/CR). In the control group (CR), the carious fissures were only sealed. Specimens were cut perpendicular to the occlusal surface and through the area of the highest demineralisation (DIAGNOdent pen, KaVo). Using confocal laser-scanning microscopy, the specimens were assessed with regard to the percentage of caries infiltration, marginal adaption and internal integrity. Within the CR group, the carious lesions were not infiltrated. Both premolar (57.9%±23.1%) and molar lesions (35.3%±22.1%) of the RI/CR group were uniformly infiltrated to a substantial extent, albeit with significant differences (P=0.034). Moreover, microleakage (n=1) and the 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 control of occlusal caries. A low-viscosity resin infiltrant combined with a flowable composite resin can effectively seal fissures in premolars and molars. A team headed by Andrej Kielbassa at Austria’s Danube Private University in Krems compared two treatments for sealing fissures in extracted human premolars and molars having occlusal caries (decay on biting surface of teeth). Comparing the infiltration and microleakage of a low-viscosity resin combined with a flowable composite resin (RI/CR) with the flowable composite resin (CR) alone, they found that no parts of the caries lesions were infiltrated in the CR group. In the RI/CR group, infiltration was uniformly substantial and microleakage was lower. The resin infiltrant evidently provided a stable basis for the flowable CR, enhancing the quality of fissure sealing. The combination treatment appears promising for clinical control of occlusal caries.