ABSTRACT
O estudo avaliou prevalência bacteriana em componentes utilizados na Radiologia Odontológica e testou a eficácia de três substâncias desinfetantes. Foram avaliadas quatro superfícies em quatro clínicas (cilindro localizador, avental de chumbo, disparador de raios X e câmara escura), sendo testados: álcool 70%, hipoclorito de sódio 2,5% e ácido peracético 0,2%. Foram utilizados os métodos bioquímicos de identificação. Em 91,7% das superfícies analisadas, houve contaminação bacteriana, sendo Staphylococcus o gênero mais prevalente, seguido dos bacilos gram-positivos. O hipoclorito de sódio 2,5% e o ácido peracético 0,2% reduziram a contaminação bacteriana de 93,8% para 6,3%, enquanto o álcool 70% reduziu de 87,5% para 56,3%, após o seu uso.
The study aimed to evaluate bacterial prevalence of dental radiology equipment and to test the effectiveness of 03 disinfection substances. 04 Surfaces were evaluated in 04 clinical (locating cylinder, lead apron, trigger X-ray and darkroom) being tested: Alcohol 70%, sodium hypochlorite 2.5% and 0.2% peracetic acid. Biochemical methods have been used for identification. In 91.7% of the areas examined were bacterial contamination, the most prevalent being Staphylococcus genus, followed by gram-positive bacilli. The 2.5% sodium hypochlorite and 0.2% peracetic acid reduced the bacterial contamination of 93.8% to 6.3%, while the 70% ethanol showed only 31.2% of bacterial absence after use.
ABSTRACT
AIM: To test the hypothesis that changes in enamel component volumes (mineral, organic, and water volumes, and permeability) are graded from outer to inner enamel after a short bleaching procedure. MATERIALS AND METHODS: Extracted unerupted human third molars had half of their crowns bleached (single bleaching session, 3 × 15 min), and tooth shade changes in bleached parts were analyzed with a spectrophotometer. Ground sections were prepared, component volumes and permeability were quantified at histological points located at varying distances from the enamel surface (n=10 points/location), representing conditions before and after bleaching. RESULTS: Tooth shade changes were significant (p<0.001; 95% CI=-1/-8; power=99%), and most of the enamel layer was unaffected after bleaching, except at the outer layers. Multiple analysis of covariances revealed that most of the variance of the change in enamel composition after bleaching was explained by the combination of the set of types of component volume (in decreasing order of relevance: mineral loss, organic gain, water gain, and decrease in permeability) with the set of distances from the enamel surface (graded from the enamel surface inward) (canonical R(2)=0.97; p<0.0001; power>99%). CONCLUSIONS: Changes in enamel composition after a short bleaching procedure followed a gradient within component volumes (mineral loss>organic gain>water gain>decrease in permeability) and decreased from the enamel surface inward.
