Aim: to investigate the marginal integrity of a bioactive resin material compared to a conventional resin-based flowable composite during management of initial carious lesion in adult population over an 18 months period.

Methodology: Twenty-four patients with an upper or lower molar that has an ICDAS score 1 or 2 on its occlusal surface, were selected for this study. The patienrs were divided randomly and equally into two groups. Group I was assigned to be sealed with a nano-filled giomer based sealant (Beautifil Injectable X, Shofu Dental Corp.) while Group II was assigned to be sealed with a nano-filled conventional flowable composite (Filtek z350 XT, 3m ESPE). Both sealants were applied after acid conditioning and the application of a bonding agent. The sealants were then evaluated for marginal integrity after six, twelve and eighteen months.

Results: There was a non-significant difference between the two groups. There was a significant difference regarding the marginal integrity within each group after eighteen months.

Conclusions: Both fissure sealants can successfully seal initially carious fissures. However, the marginal integrity of sealants should be evaluated periodically for repair. The nano-filled giomer flowable composite could be promising as a bioactive fissure sealant.