Aims: To investigate the effects of surface roughness and type of denture acrylic on the early development of a Streptococcus oralis bio®lm in a constant depth ®lm fermentor (CDFF). Methods and Results: Streptococcus oralis was incubated with acrylic of known surface roughness in the CDFF. Adherent Strep. oralis were enumerated by viable counting. Cold-cure acrylic was rougher (P < 0á01) than heat-cure acrylic after polishing with abrasive paper of any given grit-grade. Heat-cure acrylic was colonized by fewer (P < 0á001) bacteria than cold-cure acrylic at any given surface roughness. The number of bacteria adhering to heat-cure and coldcure acrylic increased linearly with mean surface roughness after 2 h incubation, the increase being greater (P < 0á001) for the cold-cure compared with the heat-cure acrylic. However, after 4 h incubation, surface roughness appeared to have no effect on the number of adherent bacteria. Conclusions: The type of acrylic used, and its roughness, affect the early stages of bio®lm formation by Strep. oralis. Signi®cance and Impact of the Study: Choosing an appropriate type of smooth acrylic could lead to reduced bio®lm formation in vivo.

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N-beta-Alanyldopamine is the major tyrosine metabolite in the hemolymph and cuticle during pupal tanning in the tobacco hornworm, Manduca sexta L. Its concentration in hemolymph increases over 800-fold above larval levels by the start of tanning and decreases as the pupal cuticle darkens and hardens. It is a major catechol in species representing several insect orders and is the preferred substrate for pupal cuticular o-diphenol oxidase. In insects, N-beta-alanyldopamine appears to be the main precursor for tanning chemicals at certain developmental stages.

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