长链硅烷偶联剂对瓷和树脂粘接强度影响的实验研究

目的：比较不同浓度、不同溶剂长链硅烷偶联剂对瓷和树脂粘接强度的影响。方法：将6种自制长链硅烷偶联剂与2种商品偶联剂处理铸瓷表面,然后采用2种树脂水门汀粘接瓷试件。对粘接试件进行即刻和老化剪切强度测试。结果：长链硅烷偶联剂能显著提高瓷和树脂的粘接强度,其中即刻粘接强度与商品偶联剂效果无显著差异（P〉0．05）;2％、4％长链硅烷乙醇溶液处理组的老化剪切强度显著高于商品偶联剂（P〈0．05）。结论：长链硅烷偶联剂的粘接耐久性优于短链商品偶联剂,其2％乙醇溶液适用于铸瓷修复体表面处理。     

含长链烷基季铵盐的纳米抗菌无机填料的合成及其在牙科复合树脂中的应用研究

目的 设计合成新型的含长链烷基季铵盐的纳米抗菌无机填料,以赋予牙科复合树脂更优良的抗菌性能。方法 在分子设计和筛选的基础上,制备了长链烷基季铵盐修饰的纳米抗菌二氧化硅填料,并对填料的抗菌性能进行评价。为进一步提高抗菌填料与树脂的结合力,采用硅烷偶联剂对抗菌填料表面进行了处理,并用红外光谱法对其结构特征进行分析;然后将新型纳米抗菌无机填料加入牙科复合树脂中,观察其在复合树脂基体中的分散情况,同时与商品化的Tetric N-Ceram纳米瓷化复合树脂进行对比;并以变异链球菌为对象,研究复合树脂的抗菌性能。结果 长链烷基季铵盐成功接枝到纳米二氧化硅颗粒表面;新型纳米抗菌无机填料的抗菌性能优于含短链烷基季铵盐的抗菌无机填料;偶联处理后的纳米抗菌无机填料在树脂基体中分散均匀,与树脂结合紧密,与Tetric N-Ceram纳米瓷化复合树脂类似;改性后的复合树脂抗菌性能良好。结论 含长链烷基季铵盐的纳米抗菌无机填料抗菌性能良好,经过表面偶联处理后可以很好地与牙科复合树脂共混,提高了牙科复合树脂的抗菌性能。     

A new method for predicting the maximum filler loading of dental resin composites based on DEM simulations and experiments

ObjectiveThe inorganic fillers in dental resin composites can enhance their mechanical properties and reduce polymerization shrinkage. When the usage amount of inorganic fillers is closed to maximum filler loading (MFL), the composites will usually achieve optimal performances. This study aims to develop a method that can predict the MFL of dental resin composites for the optimization of filler formulations.MethodsA method based on discrete element method (DEM) simulations and experiments was firstly developed to predict the MFL of spherical silica particles for single-level and multi-level filling.ResultsThe results indicate that the presence of modifier can increase the MFL, and the MFL increment can be exponentially changed with the content of the modifier. Compared with the single-level filling, the addition of secondary fillers is beneficial to increase the MFL, and the increment can be affected by the particle size and size ratio. The prediction results show a good agreement with the experiment results.SignificanceThe accuracy of prediction results indicates a great potential of DEM simulations as a numerical experimental method in studying the MFL, and provides an effective method for the optimization of filler formulations.     

The effect of resin matrix composition on the polymerization shrinkage and rheological properties of experimental dental composites.

OBJECTIVES: This study was undertaken to evaluate the effect of the resin matrix composition of experimental composites on their polymerization shrinkage and rheological properties. METHODS: Six experimental composites consisting of varying ratios of Bis-GMA, TEGDMA, and UDMA were made. All composites had the same amount of filler (barium-aluminum-silicate glass, 76.5 wt.%) and initiator concentrations (camphorquinone, 1.7 wt.%). To investigate the effects of different resin matrices on the polymerization shrinkage, a newly developed measurement method was used. Using a rotational rheometer, a dynamic oscillatory shear test was undertaken to evaluate the rheological properties, including the storage shear modulus (G'), loss shear modulus (G'), loss tangent (tandelta), phase angle (delta), and complex viscosity (eta*) of the experimental composites as a function of frequency (0.1-10Hz). RESULTS: The polymerization shrinkage and complex viscosity of the experimental composites ranged from 2.61 to 3.88 vol.% and from 3.8 to 181.4Pas, respectively. The experimental composite composed of 17.5% Bis-GMA and 4.4% TEGDMA showed the lowest shrinkage and highest viscosity. The composite composed of 8.7% Bis-GMA and 13.1% TEGDMA showed the highest shrinkage and lowest viscosity. With increasing TEGDMA content, the polymerization shrinkage increased but the viscosity decreased. The substitution of UDMA for TEGDMA reduced the shrinkage level but increased viscosity. There was an inverse relationship between the polymerization shrinkage and complex viscosity. All experimental composites exhibited pseudoplasticity. SIGNIFICANCE: Within the limitations of this study, resin matrix composition significantly affected the volumetric shrinkage and rheological properties of the experimental composites.     

The effect of post-cure heating on residual, unreacted monomer in a commercial resin composite.

OBJECTIVES: This paper examined the influence of post-cure temperature on the amount of unreacted monomer remaining in a commercial light-cured resin composite restoration following initial light-curing and subsequent post-cure heating. METHODS: Discs of composite were light-cured and then subjected to immediate post-cure heating (50, 75, 100, or 125 degrees C for 7 min) or were left unheated (control). They were then placed in a solvent for two weeks at 37 degrees C to extract the unreacted monomer. HPLC analysis was used to determine the amounts of TEGDMA, BIS-GMA, and ethoxylated BIS-GMA remaining after the different treatments. The amounts of each monomer leaching were compared using ANOVA with respect to the different curing treatments. RESULTS: Even the lowest post-cure heat treatment (50 degrees C) resulted in 80% reduction in remaining, unreacted TEGDMA, 75% reduction in BIS-GMA, and 77% lower ethoxylated BIS-GMA than the light-cured only control. Post-cure heating at 75 degrees C and above resulted in the lowest amount of each type monomer remaining uncured in the polymer and did not significantly decrease with an increase in post-cure temperature for the most part. SIGNIFICANCE: One of the main benefits of post-cure heating of resin composite restorations could be the enhancement of biocompatibility of these restorations as a result of the significant decrease in potentially leachable, unreacted monomer.     

The effect of three silane coupling agents and their blends with a cross-linker silane on bonding a bis-GMA resin to silicatized titanium (a novel silane system)

OBJECTIVES: Three activated organofunctional silane coupling agents alone and blended with a non-functional cross-linker silane were evaluated as adhesion promoters in an experiment where a bis-GMA (bis-phenol-A-diglycidyldimethacrylate) resin was bonded to silicatized titanium. The adhesive performances of the silanes were assessed as shear bond strength values. MATERIALS AND METHODS: 3-Methacryloyloxypropyltrimethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine and [3-(triethoxysilyl)propyl]urea were prepared as 1.0vol.% solutions in 95 vol.% ethanol. They were each also blended with 1.0 vol.% 1,2-bis-(triethoxysilyl)ethane solutions that were activated for 1 or 24 h. Titanium slides were cleaned, silicatized, distributed randomly to study groups and silanized with nine silane solutions. After silanization experimental bis-GMA resin stubs were photo-polymerized and post-polymerized in a light-curing unit. The shear bond strength was measured as 'dry samples' and after thermo-cycling (6000 cycles at 5-55 degrees C). RESULTS: The type of silane affected significantly the shear bond strength (p<0.001) and the use of cross-linker silane (p<0.005) according to the statistical analysis (ANOVA). It showed that the highest shear bond strength for thermo-cycled resin stub samples (n=8/group) was obtained with a blend of 1.0vol.% 3-methacryloyloxypropyltrimethoxysilane+1.0 vol.% 1,2-bis-(triethoxysilyl)ethane blend (10.4+/-3.5 MPa). The lowest results were obtained with 1.0 vol.% [3-(triethoxysilyl)propyl]urea (4.5+/-1.0 MPa), and with 1.0 vol.% N-[3-(trimethoxysilyl)propyl]ethylenediamine (4.5+/-1.4 MPa). CONCLUSIONS: Silanization with a blend of a functional silane and a cross-linker silane (a novel silane system) might improve the hydrolytic stability of a siloxane film between silicatized titanium and a bis-GMA resin.     

刷牙对老化后的光固化复合树脂的色度和微结构影响

目的：研究紫外光老化和水老化处理后的刷牙作用对光固化复合树脂的色度稳定性,表面显微结构和内部化学键的影响。方法：用紫外光老化和水老化方法处理光固化复合树脂样本,色度计测量复合树脂老化后刷牙作用造成的色差,用ESEM观察刷牙对处理后样本的表面显微结构,红外光谱仪分析复合树脂老化后刷牙作用对其化学键改变。配对t检验比较老化组间及刷牙组的复合树脂的色差。结果：紫外光老化与水老化后的复合树脂的色差均数之间的差异具有统计学意义（P〈0.05）,而复合树脂老化刷牙后的色差均数之间的差异没有统计学意义（P〉0.05）。紫外光老化后刷牙导致复合树脂的基质出现凹陷,白色颗粒凸显,且内部化学键发生了明显改变,水老化刷牙后的改变较小。结论：与复合树脂水老化后的刷牙作用相比,紫外光老化后的刷牙作用对复合树脂的表面显微结构和内部化学键破坏作用大;刷牙作用对于老化后的复合树脂的颜色改变没有影响。     

The effect of postcuring on quantity of remaining double bonds, mechanical properties, and in vitro wear of two resin composites

OBJECTIVES: To determine the effect of different postcuring methods on degree of conversion, mechanical properties, and in vitro wear of two resin composites (Z100 and Charisma). The postcuring methods involved devices for inlay curing as well as devices present for other purposes in many dental laboratories or dental offices. METHODS: Specimens of the resin composites were initially light cured and then postcured according to one of the following methods: Translux EC handheld curing unit (10min), Translux EC light box (10min), Triad II (10min), 40 degrees C (10min), 70 or 110 degrees C for 10min, 1, 6, or 24h. The properties were determined following storage of the specimens for 1week in water at 37 degrees C. The degree of conversion was determined using transmission IR. The mechanical properties tested were diametral tensile strength, flexural strength, and flexural modulus. In vitro wear was induced by a three-body wear simulator. RESULTS: Most postcuring methods increased degree of conversion of both materials. Postcuring increased the mechanical properties and in vitro wear resistance of Charisma, whereas no effect of postcuring was found on these properties of Z100. CONCLUSION: Postcuring with the use of devices readily available in the dental laboratory and dental office increased the degree of conversion of Z100 and Charisma as well as the mechanical properties and in vitro wear resistance of Charisma. A heat treatment at 110 degrees C for 10-60min was found to be the most promising postcuring method.     

The effect of high-irradiance rapid polymerization on degree of conversion,monomer elution,polymerization shrinkage and porosity of bulk-fill resin composites

ObjectiveThe purpose was to compare the degree of conversion (DC), monomer elution (ME), polymerization shrinkage (PS) and porosity of two addition-fragmentation chain transfer (AFCT) modified resin-based composites (RBC) light-cured with rapid- (RP), turbo- (TP) or conventional polymerization (CP) settings.MethodsCylindrical samples (6-mm wide, 4-mm thick) were prepared from Tetric PowerFill (TPF) and Filtek One Bulk (FOB). Four groups were established according to the polymerization settings: 3s-RP, 5s-TP, 10s-CP and 20s-CP. Samples in 1 mm thickness with 20s-CP settings served as controls. The DC at the top and bottom surfaces was measured with micro-Raman spectroscopy. ME was detected with high-performance liquid chromatography. PS and porosity were analyzed by micro-computed tomography. ANOVA and Tukey’s post-hoc test, multivariate analysis and partial eta-squared statistics were used to analyze the data (p < 0.05).ResultsFOB showed higher DC values (61.5–77.5 %) at the top compared to TPF (43.5–67.8 %). At the bottom TPF samples achieved higher DCs (39.9–58.5 %) than FOB (18.21–66.18 %). Extending the curing time increased DC (except the top of FOB) and decreased ME. BisGMA release was the highest among the detected monomers from both RBCs. The amount was three-fold more from TPF. The factor Material and Exposure significantly influenced DC and ME. PS (1.8–2.5 %) did not differ among the groups and RBCs except for the lowest value of TPF cured with the 3s_RP setting (p = 0.03). FOB showed 4.5-fold lower porosity (p < 0.001). Significantly higher pore volume was detected after polymerization in 3s_RP (p < 0.001).SignificanceHigh-irradiance rapid 3-s curing of AFCT modified RBCs resulted in inferior results for some important material properties. A longer exposure time is recommended in a clinical situation.     

三种酸蚀剂联合偶联剂对Cerinate瓷与树脂粘结强度的影响

目的：评价三种陶瓷酸蚀剂联合偶联剂对Cerinate瓷与树脂粘结强度的影响。方法：将252个Cerinate瓷试件分为3组,每组84个试件,分别用自制A配方（含2.5%氢氟酸）﹑B配方（含6%氢氟酸）、C配方（含10%氢氟酸）陶瓷酸蚀剂处理0 s﹑30 s﹑60 s﹑90 s、120 s、150 s、180 s后,一半使用偶联剂,另一半不使用偶联剂,与树脂粘结后测试其粘结强度。结果：无偶联剂组酸蚀30 s后C配方的剪切强度为27.46 MPa,偶联剂组在酸蚀30 s后C配方剪切强度可达31.08 MPa,酸蚀时间对粘结强度无明显影响。结论：C配方配合偶联剂较短酸蚀时间内可获得较理想的粘结强度。     

Effects of acidulated phosphate fluoride gel application on surface roughness, gloss and colour of different type resin composites

Objective

Application of acidulated phosphate fluoride (APF) gel has been reported to cause deterioration of resin composites. This study investigated the effects of APF gel application on surface roughness, gloss and colour of resin composites.

Methods

A2-shade resin disks of 2 mm thickness polished with 180-grit and 3000-grit SiC papers were made with Estelite Σ Quick (EQ), Clearfil Majesty (CM) and Beautifil II (B2). Six disks were prepared for each group. APF gel was applied in a 3 mm thickness on the top surface of resin disks and left for 30 min followed by rinsing and ultrasonic washing. This procedure was repeated 4 times. The L*a*b* values, colour difference (ΔE*ab), opacity, surface gloss and roughness of specimens before and after APF application were compared. Data were analysed ANOVA and Fisher's PLSD test with α = 0.05.

Results

For the 3000-grit polishing groups, the order of influence of APF gel application on colour of resin composites was CM > B2 > EQ. Both in the 180- and 3000-grit polishing groups, colour difference before and after APF gel application was hard to detect (CM and B2) or impossible to detect (EQ) by naked eye. On the other hand, for all the resin composites, the gloss was significantly decreased by APF gel application. APF gel appeared to cause deterioration and dissolution of resin composites used in this study.

Significance

In this limited study, supra-nano spherical filled Estelite Σ Quick showed the least change on colour, gloss and surface roughness by APF gel application.     

Influence of photoinitiator type on the rate of polymerization, degree of conversion, hardness and yellowing of dental resin composites

OBJECTIVES: To evaluate the degree of conversion (DC), maximum rate of polymerization (Rpmax), Knoop hardness (KHN) and yellowing (b-value) of resin composites formulated with phenylpropanedione (PPD), camphorquinone (CQ), or CQ/PPD at different concentrations. The hypotheses tested were (i) PPD or CQ/PPD would produce less Rpmax and yellowing than CQ alone without affecting DC and KHN, and (ii) Rpmax, DC, and KHN would be directly related to the absorbed power density (PDabs). METHODS: CQ/amine, PPD/amine and CQ/PPD/amine were used at low, intermediate and high concentrations in experimental composites. Photoinitiator absorption and halogen-light emission were measured using a spectrophotometer, Rp with differential scanning calorimetry (DSC), DC with DSC and FTIR, KHN with Knoop indentation; and color with a chromameter. The results were analyzed with two-way analysis of variance (ANOVA)/Student-Newman-Keul's test (p<0.05). Correlation tests were carried out between PDabs and each of DC, Rpmax and KHN. RESULTS: The PDabs increased with photoinitiator concentration and PPD samples had the lowest values. In general, maximum DC was comparable at intermediate concentration, while Rpmax and KHN required higher concentrations. DC was similar for all photoinitiators, but Rpmax was lower with PPD and CQ/PPD. PPD produced the lowest KHN. Yellowing increased with photoinitiator concentration. PPD did not reduce yellowing at intermediate and/or high concentrations, compared to CQ-formulations. PDabs showed significant correlations with DC, Rpmax and KHN. CONCLUSION: PPD or CQ/PPD reduced Rpmax in experimental composites without affecting the DC. The use of PPD did not reduce yellowing, but reduced KHN. DC, Rpmax and KHN were dependent on PDabs.     

The effect of aging methods on the fracture toughness and physical stability of an oxirane/acrylate,ormocer, and Bis-GMA-based resin composites

Clinical Oral Investigations - To determine the effect of aging methods on the fracture toughness of a conventional Bis-GMA-based resin composite (Filtek Supreme), an ormocer-based resin composite...     

The effect of light intensity on double bond conversion and flexural strength of a model, unfilled dental resin.

OBJECTIVE: Two visible light sources (tungsten-quartz-halogen and xenon-arc plasma) with vastly different intensities (200 and 1800 mW/cm(2)) but similar spectral outputs, were used to examine the effects of light intensity on conversion and flexural strength of a model dental resin formulation (75/25wt% bis-GMA/TEGDMA). METHODS: The exact same polymer samples were used to correlate double bond conversion (measured with near-IR spectroscopy) to flexural strength, both immediately after light exposure and after storage. RESULTS: In general, polymers which were irradiated with the high light intensity source exhibited greater double bond conversion. However, increasing the light intensity also increased the maximum temperature reached during polymerization. Therefore, the greater double bond conversion was caused by a combination of both photo and thermal effects. Regardless of the light intensity, a single linear relationship existed between conversion and final flexural strength (measured 4 days after cure) over the conversion range analyzed (50-80%). However, deviations from linearity were noted in several samples that were tested immediately after exposure. SIGNIFICANCE: These findings illustrate that light intensity does not affect the final flexural strength of a dental resin as long as the final conversions are similar.     

The effect of different power outputs of carbon dioxide laser on bonding between zirconia ceramic surface and resin cement

Abstract

Objective. The purpose of this in vitro study was to evaluate the influence of different power outputs of a carbon dioxide (CO2) laser on shear bond strength of resin cement to zirconium dioxide-based ceramic. Materials and methods. Fifty zirconium dioxide core specimens (10 mm diameter and 2 mm thickness) were produced and they were embedded in the centers of auto-polymerizing acrylic resin blocks. Ten specimens served as control and no surface treatment was applied. Subsequently specimens were randomly divided into four groups, each containing 10 specimens for surface treatment with CO2 laser with different output power; laser treated with 2 W (Group 2 W), 3 W (Group 3 W), 4 W (Group 4 W) and finally 5 W (Group 5 W). Fifty composite resin discs were fabricated and cemented with adhesive resin cement to the specimen surfaces. A universal test machine was used for shear bond strength test at a crosshead speed 1 mm/min. Data were statistically analyzed by one-way analyses of variance (ANOVA) with Post-Hoc Tukey tests (α = 0.05). Results. It was found that the shear bond strength values were affected by power outputs of laser (p < 0.05). Highest shear bond strength values were obtained with group 2 W (21.0 ± 2.7). Lowest values were obtained with group 5 W (14.4 ± 1.6). Conclusion. The current study revealed that there was a relationship between laser output power and shear bond strength for zirconium dioxide ceramics. However, output power of the laser and the energy level is a critical factor on micromechanical retention.     

The effect of home-use fluoride gels on glass-ionomer,compomer and composite resin restorations

The purpose of this study was to investigate the resistance to dissolution by two home-use fluoride gels on the surface integrity of glass-ionomer, resin modified glass-ionomer, compomer and composite resin restorations. Class V cavities prepared in extracted teeth were restored with a glass-ionomer (Fuji II), a resin modified glass-ionomer (Vitremenr), two compomers (Dyract and F-2000) and a composite resin (Z-100). Groups of five specimens of each material were treated for 24 h with one of the following: (i). distilled water, (ii). neutral fluoride gel and (iii). acidulated phosphate fluoride (APF) gel. Surface degradation of the restorations was studied using standard electron microscopy (SEM), rated according to specific criteria and statistically analysed by the Wilcoxon test (rank sums). Acidulated phosphate fluoride was found to have a significant effect on all examined materials, while minimal effects resulted from the neutral fluoride gel compared with the control group. The effect of home-use fluoride gels on glass-ionomer, compomer and composite resin restorations.     

The effect of fusion sputtering surface treatment on microshear bond strength of zirconia and MDP-containing resin cement

PurposeThe aim of this study is to evaluate the effect of fusion sputtering surface treatment on the microshear bond strength of zirconia and self-adhesive MDP-containing resin cement.MaterialsThirty-six zirconia discs received one of the following treatments: fusion sputtering, airborne particle abrasion with 50-μm aluminum oxide particles, while as-sintered specimens served as a control. Four treated zirconia samples from each group were examined using 3D laser scanning microscope to assess the surface roughness and scanning electron microscope to study the surface topography. The specimens of each group were bonded to composite micro discs using MDP-containing self-adhesive resin cement (Panavia SA cement plus). The specimens were thermocycled for 5000 cycles between 5 and 55 °C. Microshear bond strength test was performed using universal testing machine until bonding failure. Failure modes and fracture surfaces was evaluated using scanning electron microscope.ResultsThe fusion sputtering surface treatment significantly influenced zirconia-resin bond strength (p < 0.001). The highest mean microshear bond strength value was observed in fusion sputtering treatment (23.18 ± 4.38). The lowest value was observed in as-sintered zirconia surfaces (7.23 ± 6.26).SignificanceFusion sputtering surface treatment enhanced the microshear bond strength of zirconia and resin cement.     

Short‐term effect of strontium‐ and zinc‐containing toothpastes and mouthrinses on volatile sulphur compounds in morning breath: a randomized,double‐blind,cross‐over clinical study

Zinc (Zn) reduces the formation of volatile sulphur compounds (VSCs) associated with oral malodour. Although strontium (Sr) is included in some products for reducing dental hypersensitivity, it may also have anti‐halitosis properties. This randomized, double‐blind, cross‐over clinical study compared the anti‐VSC effect of brushing with commercial toothpastes and rinses containing Zn and Sr. The volunteers (n = 30) either brushed/rinsed with/without tongue brushing using Zn‐containing toothpaste/rinse, Sr‐containing toothpaste/rinse, or placebo (control). Volatile sulphur compounds [hydrogen sulphide (H₂S) and methyl mercaptan (CH₃SH)] were measured, in morning breath, using gas chromatography. The anti‐VSC effects of the test toothpastes and test rinses were significantly better than the anti‐VSC effects of the respective controls. Toothbrushing with test toothpastes gave median reductions, compared with the control, of 70% for H₂S and 55–57% for CH₃SH. Rinsing with the Sr‐ and Zn‐containing solutions had the same anti‐VSC effect as toothbrushing and tooth‐ and tongue brushing with the Sr‐ and Zn‐containing toothpastes. Zinc‐containing rinse resulted in a significantly higher median salivary level of Zn compared with brushing with Zn‐containing toothpaste, although this effect did not correlate with the anti‐VSC effect. It can be concluded that the Sr‐ and Zn‐containing toothpastes and the Zn‐ and Sr‐containing rinses, when used in the evening, are equally effective in reducing morning‐breath VSCs the following day.     

The effect of repeated professional supragingival plaque removal on the composition of the supra- and subgingival microbiota

BACKGROUND, AIMS: The purpose of the present investigation was to determine the effect of weekly professionally administered supragingival plaque removal on the composition of the supra and subgingival microbiota. METHODS: 18 adult subjects with periodontitis who had been treated and were in a maintenance phase of therapy were clinically and microbiologically monitored at baseline, 3, 6 and 12 months. After the baseline visit, the subjects received scaling and root planing followed by professional supragingival plaque removal every week for 3 months. Clinical measures of plaque accumulation, bleeding on probing (BOP), gingival redness, suppuration, pocket depth and attachment level were made at 6 sites per tooth at each visit. Separate supra (N = 1804) and subgingival (N = 1804) plaque samples were taken from the mesial aspect of all teeth excluding third molars in each subject at each time point and evaluated for their content of 40 bacterial taxa using checkerboard DNA-DNA hybridization. Significance of changes in mean counts, prevalence and proportions of bacterial species over time in both supra and subgingival samples were determined using the Quade test and adjusted for multiple comparisons. RESULTS: Mean % of sites exhibiting plaque, gingival redness and BOP were significantly reduced during the course of the study. Significant decreases in mean counts were observed in both supra and subgingival samples. Mean total DNA probe counts (x10(5), +/-SEM) at baseline, 3, 6 and 12 months were: 133+/-19, 95+/-25, 66+/-6, 41+/-6 (p<0.001) for supragingival samples and 105+/-22, 40+/-10, 19+/-4, 13+/-3 (p<0.001) for subgingival samples. Mean counts of 22 of 40 and 34 of 40 species tested were significantly reduced in the supra and subgingival samples respectively over the monitoring period. For example, mean counts of Porphyromonas gingivalis x10(5) at baseline, 3, 6 and 12 months in the subgingival plaque samples were 2.0+/-0.4, 0.5+/-0.2, 0.6+/-0.3, 0.3+/-0.1 (p<0.001); Bacteroides forsythus 2.0+/-0.6, 0.4+/-0.1, 0.4+/-0.2, 0.1+/-0.2 (p<0.001); Treponema denticola 3.4+/-1.1, 0.8+/-0.3, 0.4+/-0.2, 0.3+/-0.3 (p<0.01). Similar reductions were seen in supragingival plaque samples. While counts were markedly reduced by professional plaque removal, the proportion and prevalence of the 40 test species were marginally affected. CONCLUSIONS: Weekly professional supragingival plaque removal profoundly diminished counts of both supra- and subgingival species creating a microbial profile comparable to that observed in periodontal health. This profile was maintained at the final monitoring visit, 9 months after completion of therapy.     

不同浓度H2O2的桩表面处理对玻璃纤维桩与树脂水门汀黏结强度的影响

目的：研究不同浓度的H2O2表面处理对纤维桩与树脂水门汀之间黏结强度的影响。方法：选择2种不同种类的玻璃纤维桩各18支,随机分为6组,A组(对照组)、B组(单纯硅烷化处理)、C组(3%H2O2+硅烷化处理)、D组(10%H2O2+硅烷化处理)、E组(20%H2O2+硅烷化处理)和F组(30%H2O2+硅烷化处理)。将各组纤维桩与树脂水门汀进行黏结,形成圆柱状树脂块,将每个树脂块切割成7个1.0 mm厚的薄片进行推出实验,记录数据并采用SPSS13.0软件包对数据进行统计学分析。测试后的试件置于光学显微镜下,观察其破坏模式。结果：Tenax玻璃纤维桩黏结强度值A1-F1组分别为 (22.35±3.43) MPa 、(22.75±1.92) MPa、(27.21±3.60) MPa、(32.32±2.19) MPa、(36.15±2.32) MPa和(40.51±2.37) MPa,Macthpost玻璃纤维桩黏结强度值A2-F2组分别为(17.29±3.23) MPa、(17.01±3.18) MPa、(20.48±2.11) MPa 、(23.60±2.60) MPa 、(27.65±3.77) MPa和(30.52±2.99) MPa。Tenax及Matchpost组中,除了A组和B组无显著差异(P>0.05)外,其余每2组间相比,差异均有显著性(P<0.05)。结论：使用H2O2溶液处理Tenax及Matchpost玻璃纤维桩表面再涂以硅烷偶联剂,可明显提高2种玻璃纤维桩与树脂水门汀之间的黏结强度。30%H2O2溶液处理玻璃纤维桩表面的黏结强度最高,可使其更利于黏结。