Abstract
The aim of this 2-part study was to investigate whether surface properties of two resin sealants (K1, K2), a glass-ionomer (Ci) sealant, and a biomimetic hydroxyapatite (BHAP) had any effects on _in situ _biofilm formation. Standardized specimens manufactured from 4 materials and human enamel (E) were subjected to _in_ _vitro_ microhardness, surface roughness, and contact angle measurements. Then, 3 fissure sealant samples and BHAP blocks were placed on the upper removable appliances of 20 children. In the first week, biofilm was allowed to form _in situ_, then a hydroxyapatite (HAP) paste was used with renewed materials for the second week. The biofilm developed on the surfaces was analyzed using SEM and image analyzing programs. There was a statistically significant difference between the roughness of dental materials (p < 0.05). There was no difference between the microhardness of K1 and K2, whereas a statistical difference between Ci and other materials (p<0.05) was found. Ci had also statistically higher contact angle measurements than other materials (p<0.05). The _in situ_ biofilm formation was highest in Ci and lowest in BHAP materials, but not statistically different, and the biofilm formation was significantly decreased in all groups (p<0.05) with the use of the HAP paste. Within the limitations of this study, the roughness of materials correlated with the biofilm formation on BHAP, glass-ionomer, and resin sealants. The use of the HAP paste contributed to reduced biofilm formation.