Assessment of Peri-implant Soft Tissue Adaptive Pressure and Time After Provisional Restorations.

Using interim restorations to remodel the peri-implant gingiva contour has been a common procedure in esthetic implant treatment. During the interim restoration delivery, the pressure between the restoration and gingiva typically causes ischemia. Adequate restoration should allow the tissue to recover from ischemia over a certain time. To assess the time needed for peri-implant soft tissue recovery, interim restorations were delivered on 25 single implant sites 2 weeks after stage-two surgery, and the gingiva appearance changes after delivery were recorded for 15 minutes using a video camera. Gingiva color changes along the time were measured and analyzed. The color differences between peri-implant mucosa at 10 min and 0 min, as well as between adjacent tooth gingiva, were all within a clinically acceptable range of color difference. The adaptive pressure technique by two-stage contouring exhibited an optimal peri-implant soft tissue profile within 10 minutes of the adaptive time.

Comparison of Gingival Troughing by Laser and Retraction Cord.

This study was aimed at comparing the most common two methods for gingival troughing: presaturated cord and lasers (including diode, Nd:YAG, and Er:YAG). A total of 108 anterior teeth (58 maxillary and 50 mandibular) in 50 patients were included in this study. Gingival treatment was carried out in the following four groups: presaturated cord, diode laser, Nd:YAG laser, and Er:YAG laser. The gingival width and gingival recession (GR) were measured at different times (at the time of treatment, after 1 week, and after 4 weeks). The presaturated cord resulted in significantly higher (P < .05) GR than lasers and narrower gingival sulci. Er:YAG laser resulted in the quickest and most uneventful wound healing when compared to diode and Nd:YAG lasers.

Effectiveness of cysteine proteases on protein/pigment film removal.

OBJECTIVE: Theaflavin (TF) from the black tea can react to human salivary proline-rich proteins (PRPs) to form stains on exposed dental surfaces. Here, we employed a model of protein/pigment film using TF and dephosphorylated bovine ß-casein (Dß-CN), which has an extended conformation, similar to that of salivary PRPs, on a sensor surface to assess the efficacy of cysteine proteases (CPs) including papain, stem bromelain, and ficin, on removing TF bound to Dß-CN and the control TF readsorption on the residual substrate surfaces was also measured. METHODS: The protein/pigment complex film was built by using a quartz crystal microbalance with dissipation (QCM-D). The efficacies of CPs were assessed by Boltzman equation model. The surface details were detected by grazing angle infrared spectroscopy spectra, atomic force microscopy images, and contact angles. RESULTS: The efficacy order of CPs on hydrolyzing protein/pigment complex film is ficin>papain>bromelain. The results from grazing angle infrared spectroscopy spectra, atomic force microscopy images, and contact angles demonstrated that TF bound on the Dß-CN was effectively removed by the CPs, and the amount of TF readsorption on both the residual film of the Dß-CN/TF and the Dß-CN was markedly decreased after hydrolysis. CONCLUSION: This study indicates the potential application of the CPs for tooth stain removal and suggests that these enzymes are worthy of further investigation for use in oral healthcare.

[Studies on the saliva adsorption and the salivary film property on the hydroxyapatite surface].

OBJECTIVE: To evaluate the thickness and viscoelasticity of whole saliva (WS), parotid saliva (PS) and submandibular/sublingual gland saliva (SMSLS) film adsorption on the hydroxyapatite (HA) surface. METHODS: Ultra-thin layer of HA nanocrystals was coated on the dissipation TiO(2) sensor of gold quartz crystal microbalance using electrophoretic deposition technique. The thickness of the HA layer was measured by the ellipsometer, and element analysis was conducted using X-ray photoelectron spectroscopy. Atomic force microscopy and scanning electron microscope were used to observe its morphology. The in-situ adsorption thickness, the shear elastic modulus and the shear viscosity of salivary layers (WS, PS and SMSLS) on HA surfaces were investigated. The statistical data were analysed by an one-way ANOVA analysis followed by a SNK-q test. RESULTS: The results show that the HA layer was a plate-like morphology with 1.53 ± 0.12 in Ca/P molar ratio, (19.1 ± 0.9) nm in the thickness and (6.5 ± 1.6) nm in the roughness. The thickness of salivary film was SMSLS [(21.84 ± 1.25) nm] > WS[(17.91 ± 1.35) nm] > PS [(14.30 ± 1.03 nm) (P < 0.05). The shear elastic modulus of salivary film was PS [(0.61 ± 0.01) MPa] > SMSLS [(0.31 ± 0.09) MPa] and WS [(0.25 ± 0.03) MPa] (P < 0.05). The trend of the shear viscosity was opposite to one of thickness. CONCLUSIONS: The characteristics of saliva adsorption on HA surface suggest that the thicker, softer and more hydrated properties for the SMSLS and WS films are likely to afford a stronger lubrication to protect oral surfaces from wear and dehydration. The viscoelasticity of the PS film is probably related to the retention covering the oral cavity.

Effect of various pH values, ionic strength, and temperature on papain hydrolysis of salivary film.

Stimulated human whole saliva (WS) was used to study the dynamics of papain hydrolysis at defined pH, ionic strength, and temperature with the view of reducing an acquired pellicle. A quartz crystal microbalance with dissipation (QCM-D) was used to monitor the changes in frequency caused by enzyme hydrolysis of WS films, and the hydrolytic parameters were calculated using an empirical model. The morphological and conformational changes of the salivary films before and after enzymatic hydrolysis were characterized by atomic force microscopy (AFM) imaging and grazing-angle Fourier transform infrared (GA-FTIR ) spectra, respectively. The characteristics of papain hydrolysis of WS films were pH-, ionic strength-, and temperature-dependent. The WS films were partially removed by the action of papain, resulting in thinner and smoother surfaces. The infrared data suggested that hydrolysis-induced deformation did not occur on the remnants of salivary films. The processes of papain hydrolysis of WS films can be controlled by properly regulating pH, ionic strength, and temperature.

[Adsorption kinetic study of the interaction between human salivary alpha-amylase and the polyphenoles from the black/green tea].

OBJECTIVE: To explore the driving force of the oral astringency produced by the interaction of theaflavin (TF) and epigallocatechin-3-gallate (EGCG) to human salivary a-amylase(HSA). METHODS: The constants of the rate, equilibrium of reaction (k(a), k(d), K(A), and K(D)) and Langmuir, Freundlich adsorption isotherm (K(L), K(f), and Mm) were determined by surface plasmon resonance (SPR) technique and adsorption kinetics. RESULTS: Both of Langmuir and Freundlich models could be used for describing the binding processes of TF and EGCG onto HSA surfaces, and there were no significant differences of the correlation coefficient of determination between these two models (P > 0.05). The constants of adsorption isotherm, the rate and equilibrium constants of the association for TF were higher than those of EGCG (P < 0.05). The rate and equilibrium constants of the dissociation for TF were lower than those of EGCG (P < 0.05). The affinity of TF to HSA was higher than that of EGCG. CONCLUSION: The sorely oral astringency is much easily produced by TF from the black tea rather than EGCG from the green tea. The driving force of the oral astringency is attributed to the hydrogen bonds of hydroxyl groups and hydrophobic interaction of galloyl groups in polyphenolic structures.

Affinity interactions between natural pigments and human whole saliva.

OBJECTIVE: The aim of the present study was to assess the null hypothesis that there are no differences of affinity between pigments and human whole saliva (WS), and the affinity is not influenced by the functional groups of pigments, temperatures, pH values, and salt concentrations. METHODS: The affinity constants of interactions between WS and theaflavin (TF)/curcumin (Cur)/cyanidin (Cy) were determined by surface plasmon resonance (SPR) and fluorescence quenching. Mass-uptake at various temperatures, pH values, and salt concentrations was also carried out. RESULTS: The order of affinity of the pigments binding to WS is TF>Cur>Cy. A large number of complexes and precipitations of pigments/proteins were formed through a quick, strong, and almost irreversible binding process. The mass-uptake of pigments was affected not only by the functional groups, but also by molecular weight of pigments, temperatures, pH values, and salt concentrations. CONCLUSION: The complex of pigments may easily and rapidly deposit onto the WS film, and are difficult to remove from the WS surface. However, the complex of pigments can be reduced by properly regulating the physicochemical conditions, such as temperatures, pH values, and salt concentrations.

[Influence of deposition time on chromatics during nitrogen-doped diamond like carbon coating on pure titanium].

OBJECTIVE: The aim of this study was to observed the influence of deposition time on chromatics during nitrogen-doped diamond like carbon coating (N-DLC) on pure titanium by multi impulse are plasma plating machine. METHODS: Applying multi impulse are plasma plating machine to produce TiN coatings on pure titanium in nitrogen atmosphere, then filming with nitrogen-doped DLC on TiN in methane (10-80 min in every 5 min). The colors of N-DLC were evaluated in the CIE1976 L*a*b* uniform color scale and Mussell notation. The surface morphology of every specimen was analyzed using scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). RESULTS: When changing the time of N-DLC coating deposition, N-DLC surface showed different color. Golden yellow was presented when deposition time was 30 min. SEM showed that crystallization was found in N-DLC coatings, the structure changed from stable to clutter by varying the deposition time. CONCLUSION: The chromatics of N-DLC coatings on pure titanium could get golden yellow when deposition time was 30 min, then the crystallized structure was stable.

The interactions of epigallocatechin-3-gallate with human whole saliva and parotid saliva.

OBJECTIVE: The aim of the present study was to assess the null hypothesis that the astringency and loss of lubrication in the oral cavity are not related to the properties of the epigallocatechin-3-gallate (EGCG) adlayer, the affinity and the entropy-drive of EGCG binding to saliva. METHODS: The mass, thickness, and viscoelasticity of the EGCG adlayer and the temperature dependence of EGCG adsorption onto saliva surfaces were determined by quartz crystal microbalance with dissipation (QCM-D). The affinities of EGCG to human whole saliva (WS) and to parotid saliva (PS) were carried out by QCM-D monitoring and fluorescence quenching. RESULTS: The stiffer and more compact EGCG adlayers were formed on saliva surfaces at various concentrations of EGCG. The affinity for EGCG binding to WS was higher than that to PS. The precipitation of EGCG/saliva was temperature-dependent. The driving force of EGCG binding to saliva is dominated by the hydrogen bond, the hydrophobic reaction, and the entropy-drive, which were confirmed by the FTIR spectra and the measurement of temperature- dependence, respectively. CONCLUSION: The viscoelasticity of the EGCG adlayer, the affinity of EGCG to saliva, and the priority of EGCG binding to hydrophobic proteins on the mucosa may account for the oral astringency and loss of lubrication.

[Study of nitrogen silicon zirconium-hydroxylapatite as a coating on pure titanium implantation].

OBJECTIVE: To compare the osseointegration and corrosion of different kind of coatings on pure titanium. METHODS: By plasma spraying technology, nitrogen silicon zirconium-hydroxylapatite (ZrSiN-HA) compound coating was prepared on the surface of pure titanium and the pure titanium was implanted with the mandible of the experimental animal. The superficial appearance of the compound coating was observed and analyzed by scanning electron microscope (SEM). The ZrSiN-HA, nitrogen silicon zirconium (ZrSiN), hydroxylapatite (HA) and pure titanium were compared and examined. In the four groups, the bone binding force of coatings were detected, and the superficial appearance of the break regions were observed by the electronic multipurpose material testing aircraft. In the four groups, the anticorrosive of coatings were compared and examined on the electrochemistry corrosion testing system. RESULTS: Experimental results indicated that the implant surface sprayed with the ZrSiN-HA was more compact than that sprayed with HA. The crystallization was obvious. Compared with the other coatings, the bone binding force of the ZrSiN-HA coating was the highest, and its anticorrosive performance was the strongest. CONCLUSION: The application of ZrSiN-HA coating is advantageous to the long-term retention of implant, and it has huge latent application value to dental dummy.

[Evaluation of three transmission parameters of dental opal porcelains and the correlations among parameters].

OBJECTIVE: To measure the translucency parameter (TP), masking effect (ME), and contrast ratio (CR) of opal porcelain of Ceramco, Shofu, Noritake, and Vita, and to compare the correlations among the three transmission parameters, in order to provide reference for selecting opal porcelain correctly. METHODS: The color of specimens was measured according to CIE L*a*b* under different background and reflectance mode with a Color-Eye 7000A spectrophotometer. The color difference, TP, and ME value were calculated. Within 400-750 nm spectra, the ratio of light reflectance was measured, and CR was also calculated. The data was compared by ANOVA and SNK-q test (alpha=0.05). The correlation and multiple linear regression between TP, CR, and ME were analyzed (alpha=0.05). RESULTS: There were statistical difference with different shade of the same brands (P<0.05). The correlations between ME and TP, TP and CR, ME and CR were existed (P<0.05). TP was correlated not only with ME but also with CR based on multiple regression analysis (P<0.05). The partial correlation coefficients were statistically significant (P<0.05). CR was the main devotion to translucency parameter on multiple regressions. CONCLUSION: It is recommended to select opal porcelains based on transmission parameters. CR value has an inner significance of opaque property of opal porcelain and can express opacity property of opal porcelain more appropriately than ME.

[The influence of accelerated aging on color and microstructure of light-curing composite resin].

OBJECTIVE: The aim of this investigation was to examine the changes of the color stability, surface microstructure and chemical constitution of light-curing composite resin after accelerated aging, and the relations between them. METHODS: Four light-curing composite resin were aged in an accelerated aging instrument. The color was measured by CIE L*a*b* with a spectrophotometer after treatment for 24 h and 96 h. And the color differences were calculated. Environmental scanning electron microscopy (ESEM) and Fourier transform infrared spectroscopy (FTIR) spectrometer were used to examine the microstructure and chemical composition of the specimens before and after accelerated aging. The color differences were analyzed statistically by repeated-measures two-way analysis of variance and t-test after aging for 24 h and 96 h. The level of significance was defined as alpha=0.05. RESULTS: The materials demonstrated statistically significant differences in color after aging between the 24 h and 96 h (P<0.05). There were significant influences on the microstructure and the chemical composition after aging. The matrix appeared some concaves and pores, the filler particles exposed after aging. The energy of chemical bonds were weaken or broken under the aging, and the unsaturated polymer reacted again. CONCLUSION: The color differences of the composite resin increase with the aging time and irradiation dose. The hybrid filled composites have the best color stability.

[Study on the matching of the shade between beverage and modifying porcelain shade guide].

OBJECTIVE: To evaluate the matching of the shade between beverage and modifying porcelain shade guide according to Munsell color order system, thus to provide the reference basis for selecting modifying porcelain to mimic the stain of natural tooth by technician. METHODS: The shade of Vita Akzent, Vita Interno, Shofu Vintage & Unibond and Noritake Super Porcelain EX-3 shade tabs as well as 15 kinds of beverage were measured according to Munsell color order system on Color-Eye 7000A spectrophotometer. The difference of the frequency of approximate hue, value, and chroma between shade tabs and beverage were compared by calculating the Fisher exact probabilities. RESULTS: The frequency of approximate hue between 4 kinds of shade tabs and 15 kinds of bev-erage was significant different (P<0.05), while the frequency of approximate value, and chroma was not significant different (P>0.05). CONCLUSION: Except the hue, the color distribution of 4 kinds of shade tabs was similar to that of 15 kinds of beverage. But the color of beverage also can be approximately matched by any kind of modifying porcelain by mixing porcelain powder of appropriate hue, value, and chroma.