三种义齿基托材料抗白色念珠菌黏附性能的比较

目的比较3种义齿基托材料的抗白色念珠菌黏附性能。方法将热凝基托树脂、不碎胶树脂、弹性材料树脂义齿基托材料制备成粗糙度相同的标准试样,每组10个。用白色念珠菌(ATCC 90028)菌液对各试样黏附培养24h、48h、168h后,分析白色念珠菌对试件表面的黏附。结果在培养24h时,3组试件白色念珠菌黏附量差异无统计学意义(P0.05);培养48h时,除不碎胶树脂组和弹性材料树脂组外,其余两两之间差异均有统计学意义(P0.05);培养168h时,3组试件两两之间差异均有统计学意义(P0.05),白色念珠菌黏附量计数,热凝基托树脂不碎胶树脂弹性材料树脂。结论与传统热凝树脂基托相比较,不碎胶树脂基托和弹性材料树脂基托能减少白色念珠菌的黏附。     

Adherence of Candida albicans to three different denture base resins

目的 比较3种义齿基托材料的抗白色念珠菌黏附性能.方法 将热凝基托树脂、不碎胶树脂、弹性材料树脂义齿基托材料制备成粗糙度相同的标准试样,每组10个.用白色念珠菌(ATCC 90028)菌液对各试样黏附培养24h、48h、168h后,分析白色念珠菌对试件表面的黏附.结果 在培养24h时,3组试件白色念珠菌黏附量差异无统计学意义(P＞0.05);培养48h时,除不碎胶树脂组和弹性材料树脂组外,其余两两之间差异均有统计学意义(P＜0.05);培养168h时,3组试件两两之间差异均有统计学意义(P＜0.05),白色念珠菌黏附量计数,热凝基托树脂＞不碎胶树脂＞弹性材料树脂.结论 与传统热凝树脂基托相比较,不碎胶树脂基托和弹性材料树脂基托能减少白色念珠菌的黏附.     

不同基托树脂抗弯性能的比较

目的 为临床医生在基托树脂的选择上提供一个参考依据。方法 选用5种义齿基托材料，错成试件。在一定的实验条件下对试件加力，记录试件的断裂弯曲载荷。结果 不碎胶树脂断裂弯曲载荷最大，除常规热凝树脂组和BPS树脂组之间无显著性差异外，其余各组间均有显著性差异。结论 不碎胶基托树脂、BPS基托树脂和常规热凝树脂是较为理想的基托材料。大面积义齿基托不宜采用自凝和光聚合基托树脂。     

载银纳米二氧化钛树脂基托对变异链球菌和白色假丝酵母菌抗菌性的体外研究

目的采用体外法研究载银纳米二氧化钛（Ag-TiO2）树脂基托对口腔常见条件致病菌的单一游离菌体及菌斑生物膜的抗菌性能。方法将不同质量分数的Ag-TiO2抗菌粉剂添加到树脂基托材料中,制成抗菌树脂基托。采用薄膜密贴法分别检测该抗菌树脂基托对变异链球菌、白色假丝酵母菌、金黄色葡萄球菌的抗菌率,并用扫描电镜观察抗菌树脂基托表面变异链球菌、白色假丝酵母菌的生长情况。结果与未添加抗菌剂相比,抗菌剂质量分数为0.7%时,抗菌树脂基托对金黄色葡萄球菌的抗菌率达93.3%;抗菌剂质量分数为1.5%时,抗菌树脂基托对变异链球菌的抗菌率达90.2%;抗菌剂质量分数为2.5%时,抗菌树脂基托对白色假丝酵母菌的抗菌率也达91.2%。与未添加抗菌剂相比,抗菌树脂基托表面变异链球菌、白色假丝酵母菌的黏附数量明显减少。结论Ag-TiO2可以显著提高树脂基托的抗菌性能。     

注塑基托树脂力学性能的检测

目的：对Vertex注塑基托树脂的力学性能进行研究,为临床开展注塑技术提供理论依据。方法：分实验对照两组,实验组为注塑基托树脂,对照组为临床常用热凝基托树脂,按照2种基托树脂的操作步骤要求进行试样制备,对不同基托树脂的试样在材料试验机上测定其冲击强度、弯曲强度、弹性模量和布氏硬度,并对断面进行电子显微分析。结果：注塑基托树脂和热凝基托树脂的冲击强度分别为6.01±0.50KJ/mm^3,7.35±0.93KJ/mm^3,（P〉0.05）,弯曲强度为104.44±3.07MPa,90.19±6.88MPa,（P〈0.05）,弹性模量为2.1±0.2GPa,2.4±0.1Gpa,（P〉0.05）,布氏硬度为12.17±0.93kg/mm^2,19.57±2.89kg/mm^2,（P〈0.05）;两种基托树脂的微观结构有明显不同,注塑基托树脂内部分布着许多粒径颗粒。结论：Vertex注塑基托树脂不仅具有热凝基托树脂的抗冲击能力,还具有良好的抗弯性能,韧性佳,是一种比较好的义齿基托树脂。     

义齿软衬材料表面微生物粘附的实验室观察

目的比较研究口腔微生物在树脂类软衬材料和硅橡胶类软衬材料表面的粘附情况和材料表面粗糙度对微生物粘附的影响。方法将树脂类软衬材料和硅橡胶类软衬材料制备成不同粗糙度的标准试件,以硬质基托树脂为对照组;变形链球菌、粘性放线菌和白色念珠菌在试件表面粘附后脱菌、稀释、培养计数,分析3种菌在试件表面的粘附量。结果两种软衬材料的变形链球菌和白色念珠菌粘附量均大于硬质基托树脂,差异有统计学意义（P〈0．05）,硅橡胶类软衬材料的变形链球菌和白色念珠菌粘附量大于树脂类软衬材料,差异有统计学意义（P〈0．05）,不同粗糙度的同一种材料表面3种菌粘附量也有差异。结论软衬材料比硬质基托树脂更易粘附变形链球菌和白色念珠菌,硅橡胶类软衬材料比树脂类软衬材料更易粘附变形链球菌和白色念珠菌,表面粗糙度对口腔微生物的粘附有一定的影响。     

口腔放线菌对白假丝酵母菌拮抗作用的体外实验研究

目的观测3种口腔放线菌对白假丝酵母菌的生长有无抑制作用。方法采用直接点种法观察抑菌圈,分别采用反点种菌落计数法和液体共培养法,观察在口腔放线菌作用下白假丝酵母菌菌落数量的变化。结果1）各实验组均未观察到清晰的抑菌圈;2）在黏性放线菌软琼脂上的白假丝酵母菌菌落数较对照组明显减少（P<0.05）;在溶牙放线菌和内氏放线菌软琼脂上无明显白假丝酵母菌生长,与对照组相比差异有统计学意义（P<0.01）;黏性放线菌组与溶牙放线菌组、内氏放线菌组相比,白假丝酵母菌生长差异有统计学意义（P<0.01）;3）分别与3种放线菌共培养的白假丝酵母菌菌落数量减少,与对照组相比差异有统计学意义（P<0.05）;3个实验组间差异无统计学意义（P＞0.05）。结论口腔黏性放线菌、溶牙放线菌和内氏放线菌对白假丝酵母菌的体外生长有抑制作用。     

甲基丙烯酸树脂表面粗糙度与细菌黏附和色素沉着关系的研究

目的:研究甲基丙烯酸义齿基托表面粗糙度对细菌m附及色素沉着的影响.方法:将甲基丙烯酸义齿基托材料制备成粗糙度不同的7组试样,分别浸泡于白色假丝酵母菌、变形链球菌及粘性放线菌悬浮液中,通过菌落计数观察细菌黏附数,用方差分析法进行统计学分析;将试样浸泡于可口可乐中4周,对照组为人工唾液,使用电子比色仪观察各组试样色素沉着情...     

纳米无机载银磷酸锆树脂基托对6种口腔细菌的体外抗菌研究

目的:通过体外粘附实验,研究纳米无机载银磷酸锆加入到树脂基托中后是否具有抗菌性。方法:将纳米无机载银磷酸锆(Conval PAg-40型)按1%、3%、5%、7%比例添加到树脂基托中制成树脂片,未添加者为对照组,打磨抛光,金相显微镜观察试件表面无划痕、粗糙度测定仪测得表面粗糙度值无统计学差异后,采用薄膜密贴法检测该抗菌树脂片对变形链球菌、黏性放线菌、内氏放线菌、血链球菌、牙龈卟啉单胞菌、白色念珠菌的抗菌性,比较分析树脂基托抗菌性能与添加抗菌剂比例的相关性。结果:3%、5%、7%组培养的牙龈卟啉单胞菌以及1%、3%、5%、7%组培养的变形链球菌、黏性放线菌、内氏放线菌、血链球菌、白色念珠菌菌落数均低于对照组,差异有统计学意义(P<0.05),抗菌率随添加比例的增加逐渐升高;1%组培养的牙龈卟啉单胞菌菌落数与对照组相比差异无统计学意义(P>0.05)。结论:纳米无机载银磷酸锆树脂基托有良好的抗菌效能,其抗菌率随抗菌剂比例的添加而呈线性上升趋势。     

渗氮类金刚石薄膜应用于纯钛后的细菌黏附变化

采用等离子镀膜机,在纯钛试件表面沉积N-DLC薄膜、TiN薄膜、阳极氧化膜以及空白对照,然后将其黏附于树脂基托表面,实际使用6个月后,扫描电子显微镜观察白色假丝酵母菌黏附试件情况;粗糙度检测仪对比检测试件粗糙度变化。结果:白色假丝酵母菌在N-DLC膜表面附着数量比其他组试件明显少(P<0.05),且菌体生长不良,处于抑制状态;阳极氧化膜和空白对照试件表面黏附菌量最多,且菌体生长旺盛。     

3种义齿基托材料抛光后表面粗糙度的比较研究

目的研究3种义齿基托材料抛光前后的表面粗糙度度。方法选择聚甲基丙烯酸基托树脂（PMMA）、弹性义齿材料和不碎胶等3种义齿基托材料,将材料制成12mm×12mm×2mm的标准试件,每种材料各20个,对试件进行打磨和抛光后,采用表面轮廓测量仪检测材料抛光前后的表面粗糙度,通过扫描电镜对材料表面形貌进行表面观察。结果PMMA、弹性义齿材料和不碎胶抛光后表面粗糙度分别为（0．160±0．018）μm、（0．110±0．011）μm和（0．141±0．017）μ。弹性义齿材料和不碎胶的表面粗糙度低于PMMA（P〈0．05）,表面划痕也少于PMMA。结论弹性义齿材料和不碎胶更能获得抛光效果,表面粗糙度优于PMMA。     

口腔链球菌对白假丝酵母菌的拮抗作用

目的 观测3种口腔链球菌对白假丝酵母菌的生长有无抑制作用.方法 采用直接点种法、反点种菌落计数法和液体共培养法观测口腔变异链球菌、血链球菌、唾液链球菌对白假丝酵母菌的拮抗作用.结果 1)直接点种法中各组均未观察到清晰的抑菌圈;2)唾液链球菌软琼脂上的白假丝酵母菌菌落数较对照组减少(P<0.05);3)活菌与白假丝酵母菌...     

Measurement of Interfacial Porosity at the Acrylic Resin/Denture Tooth Interface

Purpose: Small pores of almost uniform shape and size are common in polymeric materials; however, significant porosity can weaken a denture base resin and promote staining, harboring of organisms such as Candida albicans , and bond failures between the artificial tooth and denture base resin. The aim of this study was to investigate the porosity at the interface of one artificial tooth acrylic resin (Trilux, copolymer of polymethyl methacrylate, ethylene glycol dimethacrylate, and color pigments) and three denture base resins: Acron MC (microwave-polymerized), Lucitone 550 (heat-polymerized), and QC-20 (heat-polymerized).
Materials and Methods: Ten specimens of each denture base resin with artificial tooth were processed. After polymerization, specimens were polished and observed under a microscope at 80× magnification. The area of each pore present between artificial tooth and denture base resin was measured using computer software, and the total area of pores per surface was calculated in millimeter square. The Kruskal–Wallis test was performed to compare porosity data (α= 0.05).
Results: Porosity analysis revealed the average number of pores (n), area range (S, mm²), and diameter range (d, μm) for Acron MC (n = 23, S = 0.001 to 0.0056, d = 35 to 267), Lucitone 550 (n = 13, S = 0.001 to 0.005, d = 35 to 79), and QC-20 (n = 19, S = 0.001 to 0.014, d = 35 to 133). The analyses showed that there were no statistically significant differences among the groups ( p = 0.7904).
Conclusions: Within the limitations of this in vitro study, it was concluded that the denture base resins evaluated did not affect porosity formation at the artificial tooth/denture base resin interface.     

Comparative study of the shear bond strength of various veneering materials on grade II commercially pure titanium

PURPOSE

To compare the shear bond strength of various veneering materials to grade II commercially pure titanium (CP-Ti).

MATERIALS AND METHODS

Thirty specimens of CP-Ti disc with 9 mm diameter and 10 mm height were divided into three experimental groups. Each group was bonded to heat-polymerized acrylic resin (Lucitone 199), porcelain (Triceram), and indirect composite (Sinfony) with 7 mm diameter and 2 mm height. For the control group (n=10), Lucitone 199 were applied on type IV gold alloy castings. All samples were thermocycled for 5000 cycles in 5-55℃ water. The maximum shear bond strength (MPa) was measured with a Universal Testing Machine. After the shear bond strength test, the failure mode was assessed with an optic microscope and a scanning electron microscope. Statistical analysis was carried out with a Kruskal-Wallis Test and Mann-Whitney Test.

RESULTS

The mean shear bond strength and standard deviations for experimental groups were as follows: Ti-Lucitone 199 (12.11 ± 4.44 MPa); Ti-Triceram (11.09 ± 1.66 MPa); Ti-Sinfony (4.32 ± 0.64 MPa). All of these experimental groups showed lower shear bond strength than the control group (16.14 ± 1.89 MPa). However, there was no statistically significant difference between the Ti-Lucitone 199 group and the control group, and the Ti-Lucitone 199 group and the Ti-Triceram group. Most of the failure patterns in all experimental groups were adhesive failures.

CONCLUSION

The shear bond strength of veneering materials such as heat-polymerized acrylic resin, porcelain, and indirect composite to CP-Ti was compatible to that of heatpolymerized acrylic resin to cast gold alloy.     

Effect of microwave disinfection on the hardness and adhesion of two resilient liners

STATEMENT OF PROBLEM: Microwave irradiation has been suggested for denture disinfection. However, the effect of this procedure on the hardness and bond strength between resilient liners and denture base acrylic resin is not known. PURPOSE: This study evaluated the effect of water storage time and microwave disinfection on the hardness and peel bond strength of 2 silicone resilient lining materials to a heat-polymerized acrylic resin. MATERIAL AND METHODS: Acrylic resin (Lucitone 199) specimens (75 x 10 x 3 mm) were stored in water at 37 degrees C (2 or 30 days) before bonding (n = 160). The resilient lining materials (GC Reline Extra Soft and Dentusil) were bonded to the denture base and divided into the following 4 groups (n = 10): Tests performed immediately after bonding (control); specimens immersed in water (200 mL) and irradiated twice, with 650 W for 6 minutes; specimens irradiated daily for 7 total cycles of disinfection; specimens immersed in water (37 degrees C) for 7 days. Specimens were submitted to a 180-degree peel test (at a crosshead speed of 10 mm/min) and the failure values (MPa) and mode of failure were recorded. Pretreatment and posttreatment hardness measurements (Shore A) of the resilient materials were also performed. Three-way analysis of variance, followed by the Tukey HSD test, was performed (alpha = .05). RESULTS: The analysis revealed that, for all conditions, the mean failure strengths of GC Reline Extra Soft (0.95-1.19 MPa) were significantly higher ( P < .001) than those of Dentusil (0.45-0.50 MPa). The adhesion of the liners was not adversely affected by water storage time of Lucitone 199 or microwave disinfection. All peel test failures were cohesive. There was a small but significant difference ( P < .001) between the pretreatment (34.33 Shore A) and posttreatment (38.69 Shore A) hardness measurements. CONCLUSION: Microwave disinfection did not compromise the hardness of either resilient liners or their adhesion to the denture base resin Lucitone 199.     

In vitro attachment of Streptococcus sanguis to dental crown and bridge cements

The ability of a common dental plaque bacterium, Streptococcus sanguis, to adhere to dental crown and bridge cements in vitro was investigated. Cylindrical blocks of five different commercial brands of cement, with and without acquired pellicles, were indubated with buffer suspensions of S. sanguis for 1 h. Attached bacteria were counted under the microscope. S. sanguis had particularly high affinity for uncoated resin cement. In contrast, the carboxylate cement tested was a poor substrate for the adherence of this bacterium. The other cement types (zinc phosphate, zinc oxide and silico-phosphate) had intermediary qualities as adhering surfaces. The presence of an acquired pellicle, obtained by pretreatment with saliva, influenced the initial adherence of bacteria to cement in vitro. On the resin cement a salivary pellicle strongly suppressed the bacterial adhesion. For the zinc phosphate, zinc oxide and silico-phosphate cements a pellicle slightly enhanced the attachment of S. sanguis. On the carboxylate cement only few organisms attached also after pretreatment with saliva.