Objective: The aim of this study was the evaluation of two different photosensitizers activated by red light emitted by light-emitting diodes (LEDs) in the decontamination of carious bovine dentin. Materials and Methods: Fifteen bovine incisors were used to obtain dentin samples which were immersed in brain-heart infusion culture medium supplemented with 1% glucose, 2% sucrose, and 1% young primary culture of Lactobacillus acidophilus 10 8 CFU/mL and Streptococcus mutans 10 8 CFU/mL for caries induction. Three different concentrations of the Photogem solution, a hematoporphyrin derivative (1, 2, and 3 mg/mL) and two different concentrations of toluidine blue O (TBO), a basic dye (0.025 and 0.1 mg/mL) were used. To activate the photosensitizers two different light exposure times were used: 60 sec and 120 sec, corresponding respectively to the doses of 24 J/cm 2 and 48 J/cm 2 . Results: After counting the numbers of CFU per milligram of carious dentin, we observed that the use of LED energy in association with Photogem or TBO was effective for bacterial reduction in carious dentin, and that the greatest effect on S. mutans and L. acidophilus was obtained with TBO at 0.1 mg/mL and a dose of 48 J/cm 2 . It was also observed that the overall toxicity of TBO was higher than that of Photogem, and that the phototoxicity of TBO was higher than that of Photogem. Conclusion: Based on our data we propose a mathematical model for the photodynamic effect when different photosensitizer concentrations and light doses are used.

The study of the interaction of intense laser light with matter, as well as transient response of atoms and molecules is very appropriated because of the laser energy concentration in a femtosecond optical pulses. The fundamental problem to be solved is to find tools and techniques which allow us to observe and manipulate on a femtosecond time scale the photonics events on and into the matter. Six third human extracted molars were exposed to a femtosecond Ti:Sapphire Q-switched and mode locked laser (Libra-S, Coherent, Palo Alto, CA, USA), emitting pulses with 70 fs width, radiation wavelength of 801 nm, at a constant pulse repetition rate of 1 KHz. The laser was operated at different power levels (70 to 400 mW) with constant exposition time of 10 seconds, at focused and defocused mode. Enamel and dentin surfaces were evaluated concerned ablation rate and morphological aspects under scanning electron microscopic. The results in this present experiment suggest that at the focused mode and under higher average power, enamel tissues present microcavities with higher depth and very precise edges, but, while dentin shows a larger melt-flushing, lower depth and melting and solidification aspect. In conclusion, it is possible to choose hard or soft ablation, under lower and higher average power, respectively, revealing different aspects of dental enamel and dentin, depending on the average power, fluence and distance from the focal point of the ultra-short pulse laser on the tooth surface.

Analisar as complicações iatrogênicas apresentadas por idosos hospitalizados. Estudo retrospectivo dos prontuários de 96 pacientes, 48 do sexo masculino e 48 do feminino, com idades variando de 60 a 93 anos (média: 75,7 anos), hospitalizados durante o ano de 1995 em enfermaria geriátrica. A análise da evolução dos pacientes durante o período de hospitalização permitiu evidenciar: 1) em 42 (43,7%) pacientes ocorreram uma ou mais complicações iatrogênicas, num total de 56 episódios; 2) manifestações relacionadas aos procedimentos diagnósticos corresponderam a 17,9% das iatrogenias; 3) alterações relacionadas às medidas terapêuticas corresponderam a 58,9%, sendo 32,1% referentes à terapêutica farmacológica e 26,8% a outros procedimentos terapêuticos; 4) manifestações iatrogênicas não relacionadas diretamente às afecções (úlceras de decúbito, quedas e fraturas) corresponderam a 23,2%; 5) a presença de manifestações iatrogênicas correlacionou-se com período mais prolongado de internação; 6) cinco pacientes faleceram em conseqüência direta de complicações iatrogênicas. A iatrogenia é freqüente em pacientes idosos hospitalizados, podendo determinar manifestações graves e mesmo fatais. Como uma significativa proporção dessas complicações pode ser evitada através de medidas adequadas, deve-se procurar identificar suas causas e desenvolver métodos para previni-la ou reduzir seus efeitos.