The effects of firing numbers on the opening total pore volume, translucency parameter and color of dental all-ceramic systems / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effects of firing numbers on the total opening pore volume (TPV), translucency parameter (TP) and color of dental all-ceramic systems.</p><p><b>METHODS</b>Specimens of three kinds of all-ceramics systems were made, i.e. heat pressed all-ceramic (IPS Empress II), alumina all-ceramic (In-Cream alumina blanks) and zirconia all-ceramic (Cercon CAD/CAM zirconia). The specimens' TP, lightness (deltaL), chroma (deltaC) and TPV after 1, 3 and 5 firings were measured and calculated by spectrophotometer and surface area/porosity system. The data were analyzed statistically using SAS 8.0 software.</p><p><b>RESULTS</b>There were significant differences in TPV, TP, deltaL and deltaC for all-ceramic specimens at same number of firings (P<0.05), i.e. IPS>alumina and zirconia for TPV (P<0.05); IPS>zirconia>alumina for TP and deltaL (P<0.05); IPS and alumina>zirconia for deltaC (P<0.05). The significant differences also presented in TPV, TP, deltaL and deltaC for a same specimen at different number of firings (P<0.05). With increasing number of firings, TPV decreased, and TP, deltaL and deltaC increased gradually. There were negative linear correlation between number of firings and TPV, TP, deltaL and deltaC (P<0.05).</p><p><b>CONCLUSION</b>Repeated firings will affect TP and deltaL of all-ceramic restorations via the change of TPV.</p>

Adsorption dynamics study on interactions of pigments and human whole saliva / 华西口腔医学杂志

<p><b>OBJECTIVE</b>In situ, real timely and dynamically monitoring the processes of theaflavin (TF), curcumin (Cur) and cyanidin (Cy) binding to human whole saliva (WS) surface has been investigated by surface plasmon resonance (SPR) technique at the molecular level.</p><p><b>METHODS</b>The affinity between pigments and WS, association rate constant (k(a)), dissociation rate constant (k(d)), association equilibrium constant (K(A)) and dissociation equilibrium constant (K(D)) of pigments binding on WS surface had been determined by SPR and the Langmuir model as well as the Freundlich model. The data were analyzed by one-way ANOVA and SNK-q test.</p><p><b>RESULTS</b>There were significant differences among TF, Cur and Cy in k(a), k(d), K(A) and K(D) (P<0.05). Our results showed that the adsorption isotherm of pigments on WS surface could be better described by the Freundlich model than the Langmuir model. The pigments adsorption on WS surface was dominant by specific interactions, such as hydrogen bonding. The affinity of pigments to WS were TF> Cur>Cy (P<0.05), as evidenced by the rate constants and equilibrium constants.</p><p><b>CONCLUSION</b>Compared with Cur and Cy, TF shows much higher adsorption capacity on WS surface, suggesting the importance of the hydroxyl group in pigment/protein interactions.</p>

Fluorescence properties and color space of modifying porcelains / 实用口腔医学杂志

Objective:To investigate the correlation between fluorescence emission and color difference (CIE△Eab). Methods:Color and spectral distribution in three kinds of modifying porcelains (Vita Interno, Shofu Vintage & Unibond, Noritake Super Porcelain EX-3) were measured on CIELAB color scale on Color-Eye 7000A spectrophotometer under four measuring modes. CIE△Eab were analyzed by two-way ANVOA and SNK-q test (?=0.05). Correlation analyses were also performed between CIE△Eab and the color parameters difference(?= 0.05). In addition, CIELAB color coordinate was established. Results:Fluorescence emission of Vita and Shofu, Vita and Noritake were significantly different(P