To relate the characteristics of rotary instruments to the surfaces they produce, acrylic resin, Molloplast B, and Novus were investigated with energy dispersive analysis and scanning electron microscopy (secondary and backscatter images) before and after machining. The chemical composition of cutting instruments, material surfaces, and residues was identified. Machined debris embedded in Molloplast B after machining with the Molloplast stone was found to contain a mean lead content of 45%. High concentrations of barium sulphate were discovered on the arbor band-machined surface of Novus. These differences were related to clinically appropriate instrumentation, and, therefore, biocompatibility studies that intimately relate to the in vivo situation should be considered for new materials.

Dental Polishing↗

PubMedDate not supplied

Adherence of phenotypically switched Candida albicans to denture base materials.

PURPOSE: The purpose of this study was to investigate in vitro the levels of adhesion of phenotypically switched and nonswitched Candida albicans to the smooth and rough surfaces of heat-cured acrylic resin, Molloplast B, and Novus. MATERIALS AND METHODS: Nonswitched and switched cells of C. albicans 3153A were prepared and adhesion assays were performed. RESULTS: There was no difference in the level of adhesion of blastospores in their nonswitched or switched state. The adherence of hyphae to all three denture base materials was statistically significantly increased when in a switched form. There was greater adhesion to the two soft lining materials than to the acrylic resin. CONCLUSIONS: Rough surfaces promote adhesion. There was no significant difference in the adhesion of switched and nonswitched blastospores, but there was increased adhesion of hyphal cells.

Acrylic Resins↗