Huriel Scartazzini Palhano

Objective: To evaluate the antimicrobial action, cytotoxicity, pH, flow, and radiopacity of an experimental paste for primary teeth. Material and Methods: Root canals of 50 extracted human teeth were inoculated with Enterococcus faecalis and divided into five groups (n=10): G1 - distilled water (negative control); G2 - zinc oxide-eugenol (ZOE) paste; G3 - calcium hydroxide (Ca(OH)2) paste; G4 - iodoform paste; and G5 - experimental paste containing chlorhexidine, (Ca(OH)2), neomycin sulfate, and barium sulfate. Colony-forming unit counts assessed antimicrobial activity. Cytotoxicity was analyzed in fibroblast cells through cell viability assays. pH and flow were measured with colorimetric strips and dispersion diameter, respectively. Radiopacity was compared to an aluminum scale using digital radiography. Statistical analysis was performed at α=5%. Results: High antimicrobial activity and radiopacity were observed in groups 2 (ZOE paste), 3 (Ca(OH)2 paste), 4 (iodoform paste), and 5 (experimental paste) (p<0.05). The highest cell viability was found in groups 1 (distilled water), 4 (iodoform paste), and 5 (experimental paste) (p<0.05). Groups 3 and 5 showed the highest pH values, while flow was highest for groups 3 (Ca(OH)2 paste), 4 (iodoform paste), and 5 (experimental paste) (p<0.05). Conclusion: The experimental paste demonstrated a satisfactory antimicrobial effect, cytocompatibility, an alkaline pH, adequate flow, and radiopacity, comparable to conventional pastes, and has potential for clinical application.

This study evaluated bond strength of glass fiber posts to root dentin using push‐out (PO) and diametral compression (DC), testing glycolic acid as a conditioner and varying dentin moisture. An additional aim was to test whether DC can be an alternative test to PO for bond strength assessment. Eighty bovine teeth were divided into eight groups (n = 10) defined by the use of either 37% glycolic acid or 37% phosphoric acid (PA) on moist or wet dentin before bonding with either Adapter SingleBond/RelyX ARC or One Step Plus/Duo‐Link Bisco. Each tooth provided discs with an internal diameter of 2 mm, external diameter of 5 mm, and height of 2 mm, which underwent PO and DC. Finite element analysis (FEA) was carried out on 3D models. When analyzing PO results through linear regression, the highest values of bond strength were observed using glycolic acid on wet dentin in the cervical and middle thirds of the teeth. Analyzing DC results, the only statistical influence on values was the dental thirds. The scatterplot of the DC results and the PO bond strength values indicated no relationship between the results of the two tests (r = 0.03; p = 0.64). PO test detected more sensitive changes in bond strength values than DC.