The effect of sandblasting duration on the bond durability of dual-cure adhesive cement to CAD/CAM resin restoratives

PURPOSE: To evaluate the effect of prolonged sandblasting on the bond durability of dual-cure adhesive resin cement to computer-aided design and computer-aided manufacturing (CAD/CAM) restoratives. MATERIALS AND METHODS: Nano-ceramic LAVA Ultimate and hybrid-ceramic VITA Enamic CAD/CAM blocks were used for this study. Each CAD/CAM block was sectioned into slabs of 4-mm thickness for the microtensile test (µTBS) test and 2-mm thickness for the surface roughness test. Three groups were created according to the sandblasting protocols; group 1: specimens were sandblasted for 15 seconds, group 2: specimens were sandblasted for 30 seconds, and group 3: specimens were sandblasted for 60 seconds. After sandblasting, all specimens were luted using RelyX Ultimate Clicker. Half the specimens were subjected to µTBS tests at 24 hours, and the other half were subjected to tests after 5000 thermocycles. Additionally, a total of 96 CAD/CAM block sections were prepared for surface roughness tests and scanning electron microscopy (SEM) evaluations. The Mann-Whitney U test, Kruskal-Wallis one-way analysis of variance, and Dunn's post hoc test were used to compare continuous variables among the groups. RESULTS: At baseline, group 1, group 2, and group 3 exhibited statistically similar µTBS results for LAVA. However, group 3 had significantly lower µTBS values than groups 1 and 2 for VITA. After 5000 thermocycles, µTBS values significantly decreased for each block (P < .05). CONCLUSION: It is important to perform controlled sandblasting because it may affect bond strength results. Sixty seconds of sandblasting disturbs the initial µTBS values and the stability of adhesion of CAD/CAM restoratives to dual-cure adhesive resin cement for VITA Enamic.

The effect of glazing and aging on the surface properties of CAD/CAM resin blocks

PURPOSE: To investigate the effect of accelerated aging on surface properties of glazed CAD/CAM resin blocks using a 2D surface profilometer and a 3D non-contact optical profilometer. MATERIALS AND METHODS: Three types of CAD/CAM resin restorative materials, LAVA Ultimate (3M ESPE, St Paul, MN, USA), VITA Enamic (Vita Zahnfabrik H. Rauter, Bad Säckingen, Germany), and Cerasmart (GC Corparation, Tokyo, Japan) were used for this study. CAD/CAM blocks were cut in 3-mm thickness slabs and divided into three groups; Group 1: control group (specimens polished with 600 grit SCI paper); Group 2: specimens sandblasted, silanized, and glazed with Optiglaze Color (GC); Group 3: glazed specimens subjected to 5000 thermocycles (n=15). The surface roughness (Ra and Rz) was evaluated using a profilometer and a 3D scanning instrument. Data were analyzed using two-way ANOVA and Tukey's post-hoc test (P .05). For VITA and Cerasmart, the specimens in Group 1 exhibited significantly higher Ra values than Group 2 (P .05). CONCLUSION: Glaze material Optiglaze Color makes CAD/CAM resin surfaces smooth and glazed CAD/CAM surfaces seem resistant to deterioration under 5000 thermocycles.

Detecção de adulterações do leite pasteurizado por meio de provas oficiais / Detection of pasteurized milk adulteration through official methods

A qualidade do leite consumido é uma constante preocupação dos técnicos e autoridades ligados à área de saúde e laticínios bem como dos consumidores. Um dos problemas mais graves são as diversas fraudes que causam prejuízos econômicos, riscos à saúde dos consumidores e, às vezes, problemas para as indústrias, como a diminuição do rendimento industrial. Muitos alimentos estão sujeitos às fraudes, mas o leite é um dos mais comumente fraudados. O objetivo do presente trabalho foi determinar a presença de substâncias fraudulentas e avaliar as características físico-químicas do leite pasteurizado produzido em laticínios da região norte do Paraná. Foram avaliadas 80 amostras no período de março a junho de 2014 e realizadas provas específicas para detecção dos reconstituintes: amido, álcool, cloreto e sacarose; neutralizantes: bicarbonato e hidróxido de sódio; conservantes: cloro, hipoclorito, peróxido de hidrogênio e formaldeído. A avaliação das características físico-químicas foi realizada através das seguintes análises: densidade a 15°C, índice crioscópico, acidez titulável Dornic, estabilidade ao alizarol 72%, pH, fosfatase alcalina, peroxidase, teor de gordura, sólidos totais, sólidos não gordurosos, ureia, proteína e lactose. Foram verificadas amostras fora do padrão para as seguintes análises: gordura (12,5%), sólidos não gordurosos (5%), densidade (1,25%), crioscopia (3,75%),pH (48,75%), ureia (1,25%). Foram verificadas fraudes por adição de água e sacarose (3,75%), presença de hipoclorito (5%) e ocorrência de desnate (12,5%). As provas em conjunto podem auxiliar na detecção das fraudes mais comumente realizadas no leite pasteurizado, porém não mostra em qual segmento podem ter ocorrido. No entanto, se não detectada, não se pode assegurar a qualidade do produto visto que muitas fraudes têm sido realizadas de forma equilibrada dificultando sua detecção.

The quality of milk consumed is a constant concern of dairy industry and healthcare-related authorities, technicians as well as consumers. The most serious problems are the various frauds which cause economic losses, risks to consumer health and, sometimes, problems for industries, such as the decrease in industrial output. Many foods are subject to fraud, but milk is one of the most commonly spoofed. The purpose of this study was to determine the presence of fraudulent substances and assess the physico-chemical properties of pasteurized milk produced in dairies from the North region of Paraná. Eighty samples were evaluated in the period from March to June 2014 and carried out specific methods for detection of restoratives: starch, alcohol, chloride and sucrose; neutralizers: bicarbonate and sodium hydroxide; preservatives: chlorine, sodium hypochlorite, hydrogen peroxide and formaldehyde. The evaluation of physico-chemical characteristics was carried out through the following analyses: density at 15° C, cryoscopic index, Dornic titratable acidity, 72 alizarol stability, pH, alkaline phosphatase, peroxidase, fat, total solids, non-fat solids, urea, protein and lactose. Non-standard samples were observed for the following analyses: fat (12.5%), non-fat solids (5%), density (1.25%), cryoscopy (3.75%), pH (48.75%), urea (1.25%). Frauds were observed by addition of water and sucrose (3.75%), presence of hypochlorite (5%) and occurrence of skim milk (12.5%). The evidence together can assist in detecting fraud most commonly performed in pasteurized milk, but does not show in which thread might have occurred. However, if not detected, the quality of the product cannot be assured since many frauds have been carried out in a balanced way hindering its detection.

Biosmart Dentistry.

A good aesthetic appeal occupies a top priority in all fields of dentistry, which leads to an increased quest and concern towards better and more efficient technological perspectives. It poses a great challenge that has always been soaring high eventually from time immemorial. Today the most promising technologies for life time efficiency and improved reliability include the use of smart materials and structures. Smart materials are being used, and are continually being developed, for medical, defensive and industrial purposes. The recent advances in the design of smart materials have created novel opportunities for their applications in bio-medical fields. One of the important application is dental restoratives.