In vitro evaluation of different chemical agents for the decontamination of gutta-percha cones Avaliação in vitro de diferentes agentes de descontaminação de cones de guta-percha

This study evaluated the effectiveness of three disinfectants used in Dentistry for decontamination of gutta-percha cones. Sixty gutta-percha cones were contaminated with standardized pure cultures of five species of microorganisms (Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, Candida albicans ATCC CBS-ICB/USP 562, Bacillus subtilis spores ATCC 6633 and Streptococcus mutans ATCC 25175). The cones were treated with 10% polyvinylpyrrolidone-iodine aqueous solution (PVP-I; Groups 1 and 2), 5.25% aqueous sodium hypochlorite (Groups 3 and 4) and paraformaldehyde tablets (Group 5). All chemical agents were efficient for the cold sterilization of gutta-percha cones in short time periods.<br>A eficiência de três desinfetantes usados em Odontologia foi estudada na descontaminação de 60 cones de guta-percha contaminados com culturas puras e padronizadas de cinco cepas de microrganismos (Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, Candida albicans ATCC CBS-ICB/USP 562, Bacillus subtilis em esporos ATCC 6633 e Streptococcus mutans ATCC 25175). Os cones foram tratados com solução aquosa de polivinilpirrolidona-iodo 10% (PVP-I; Grupos 1 e 2), solução aquosa de hipoclorito de sódio 5,25% (Grupos 3 e 4) e pastilhas de formaldeído (Grupo 5). Nossos resultados indicam que todos os agentes químicos foram eficientes para a esterilização a frio dos cones de guta-percha em curtos espaços de tempo

The decay of the observed J&quot;P&quot;C=1&quot;-&quot;+(1400) and J&quot;P&quot;C=1&quot;-&quot;+(1600) hybrid candidates

We study the possible interpretation of the two exotic resonances J&quot;P&quot;C=1&quot;-&quot;+ at 1400 and 1600 MeV, claimed to be observed by BNL, decaying respectively into #eta##pi#, #eta#'#pi#, f_1#pi# and #rho##pi#. These objects are interpreted as hybrid mesons, in the quark-gluon constituent model using a chromaharmonic confining potential. The quantum numbers J&quot;P&quot;CI&quot;G=1&quot;-&quot;+1&quot;- can be considered in a constituent model as an hybrid meson (qqg). The lowest J&quot;P&quot;C=1&quot;-&quot;+ states may be built in two ways: l_g=1 (gluon-excited) corresponding to an angular momentum between the gluon and (qq) system, while l_q _a_n_t_i _q=1 (quarks-excited) corresponds to an angular momentum between q and q. For the gluon-excited mode 1&quot;-&quot;+ hybrids, we find the decay dominated by the b_1#pi# channel, and by the #rho##pi# channel for the quark-excited mode. In our model, neither the quark-excited nor the gluon-excited 1&quot;-&quot;+ (1400 MeV) hybrids can decay into #eta##pi# and #eta#'#pi#, in contradiction with experiment. Hence, the 1400 MeV resonance seems unlikely to be an hybrid state. The 1&quot;-&quot;+ (1600 MeV) gluon-excited hybrid is predicted with too large a total decay width, to be considered as an hybrid candidate. On the contrary the quark-excited mode has a total decay width around 165 MeV, with a #rho##pi# preferred decay channel, in agreement with BNL. Our conclusion is that this resonance may be considered as a hybrid meson in the quark-excited mode. (orig.)Available from TIB Hannover: RA 2999(00-148) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman