柠檬精油对牙周病主要致病菌粘附作用影响的体外研究

目的:研究柠檬精油(LEO)对牙周病主要致病菌黏附作用的影响,探讨其用于预防和治疗牙周病的可行性。方法:光滑聚苯乙烯表面黏附的影响:将菌液与实验分组中各组药液混合培养于96孔板48h,检测各孔内细菌附着情况;蛋白包被聚苯乙烯表面黏附的影响:将菌液与实验分组中各组药液混合培养于形成蛋白包被表面的96孔板48h,检测各孔内细菌附着情况。结果:光滑聚苯乙烯表面黏附的影响:Aa、Pi中LEO组与对照组比较差异无统计学意义,Pg、Fn中LEO组与对照组比较差异有统计学意义(P<0.05);蛋白包被聚苯乙烯表面黏附的影响:Aa、Pg、Pi、Fn中LEO组与对照组比较差异有统计学意义(P<0.05),LEO能抑制Aa、Pg、Pi、Fn在蛋白包被表面的黏附,对Pg、Fn在光滑聚苯乙烯表面的黏附也有抑制作用。结论:LEO能抑制病原菌对牙面的黏附,阻断牙菌斑的形成,具有预防牙周病的作用。     

纳米银改性钛片对口腔常见致病菌抗菌性能实验研究

目的：通过纳米银改性钛片对牙龈卟啉单胞菌和伴放线放线杆菌抗菌能力的观察,探讨口腔种植体颈部钛表面抗菌改性的可行性。方法：实验组为纳米银改性钛片,对照组为光滑钛片,每组各10片。通过贴膜法和抗粘附实验两种方法检测纳米银改性钛片的抗菌性能。结果：贴膜法显示培养24 h后纳米银改性钛片对牙龈卟啉单胞菌和伴放线放线杆菌的抗菌率达到90％;抗粘附实验显示牙龈卟啉单胞菌散在分布,且对照组多于实验组,伴放线放线杆菌散在分布对照组钛片上大量粘附,呈片状或团状集聚在一起。结论：纳米银改性后的钛片抗菌性能突出,是一种具有前景的抗菌生物植入材料。     

Surface antibacterial properties of packable resin composites: part I.

OBJECTIVE: Restorative materials that possess antibacterial properties are considered advantageous. The aim of this study was to test the antibacterial properties of packable resin composite materials using a direct contact test (DCT) and an agar diffusion test (ADT). METHODS AND MATERIALS: Quadruple samples of SureFil, Alert, P-60, Synergy Compact, Pyramid, and Solitair were placed on the sidewalls of wells in a 96-microtiter plate, and polymerized. A suspension of 10-microL growth medium containing ca. 1 x 10(6) viable mutans streptococci cells were placed on the surface of each sample for 1 hour at 37 degrees C. Fresh medium was then added to each well, and the microtiter plates were placed in a temperature-controlled spectrophotometer which also served as an incubator. Bacterial growth was followed by recording the changes in optical density every 30 minutes for 16 hours. The ADT was performed by placing samples in punched wells of inoculated agar plates, and measurement of the inhibition zone was performed after 72 hours. RESULTS: In both tests, none of the materials inhibited growth of S. mutans. In the DCT, three materials enhanced bacterial growth. Composite samples, aged in phosphate buffered saline for 7 and 30 days, showed no differences when on tested material and controls. CONCLUSIONS: Packable composite materials revealed no antibacterial properties. Furthermore, freshly polymerized composites supported bacterial growth.     

Antibacterial effects of resinous retrograde root filling materials

The effect of three resinous retrograde root filling materials on the growth of four obligate anaerobic bacteria associated with endodontic infections was determined by using the agar diffusion inhibitory test. Samples of the following resinous materials (resin-modified, glass-ionomer cement, Fuji II LC; compomer, Dyract; and composite resin, Spectrum) were incubated for 1 week with the following anaerobic bacteria: Fusobacterium nucleatum, Porphyromonas gingivalis, P. endodontalis, and Prevotella intermedia. The freshly mixed and set resinous materials were placed into the prepared wells of agar plates inoculated with the test microorganisms for 1 week. After the end of the incubation period, the zone of growth inhibition was observed and measured. Analysis of variance of the mean diameter of the zone of inhibition indicated no statistically significant overall differences in the response of the black-pigmented Bacteroides species (p > 0.05). For F. nucleatum, Spectrum had more antibacterial effect against this bacteria than Dyract (p < 0.05). Additionally, Fuji II LC was ineffective against F. nucleatum (p < 0.05). However, positive control plates showed bacterial growth in all cases. Our data suggest that the antibacterial potency of polymerized materials varied considerably, depending on the type and the product tested.     

Antibacterial surface properties of polymerized single-bottle bonding agents: part II.

OBJECTIVE: Microorganisms are directly associated with the etiology of enamel, dentin, and pulpal pathology. Due to the growing usage of one-bottle bonding materials with resin composite restorations, as well as sealing agents with amalgam restorations, it is important that they possess antibacterial properties. In the present study, the antibacterial properties of polymerized one-bottle bonding agents were tested, using the direct contact test (DCT) and the agar diffusion test (ADT). METHOD AND MATERIALS: Quadruple samples of the following materials were tested in both assays: Bond-1, OptiBond Solo, One-Step, Gluma, Prime & Bond NT, and Synergy. In the DCT, samples were placed on the sidewalls of wells of a 96-microtiter plate and polymerized. A 10-microL suspension of Streptococcus mutans was placed on the surface of each sample for 1 hour at 37 degrees C. Fresh media was then added, and bacterial growth was followed with a temperature-controlled spectrophotometer. In the ADT, samples were placed in punched wells of inoculated agar plates, and halos in the bacterial lawn were measured after 72 hours. RESULTS: In the DCT, all the tested bonding agents exhibited potent antibacterial properties; virtually no viable bacteria were present in any of the samples. When the samples were aged in phosphate-buffered saline for 24 hours, all the tested agents, similar to the freshly polymerized samples, exhibited potent antibacterial properties. This property was lost in samples aged for 7 days. Fresh samples assayed by ADT demonstrated no inhibition halo around any of the samples. CONCLUSION: Collectively, the present data suggest that one-bottle bonding agents possess in vitro antibacterial properties for at least 24 hours. This phenomenon was demonstrated only by DCT.     

Determination of polymerization shrinkage kinetics in visible-light-cured materials: methods development.

An instrument for the reproducible measurement of polymerization shrinkage kinetics is described, constructed around a disc-shaped specimen sandwiched between two glass plates. Test specimens of light-sensitive dental restorative materials were irradiated through the lower, rigid plate. The upper, non-rigid plate was readily deflected by an increase of the adhesive stress from the polymerizing and shrinking sample. Deflection was measured by an LVDT transducer and computer-recorded. Dimensional changes were confined to the specimen disc-thickness dimension, such that the fractional linear shrinkage approximated the volumetric shrinkage. Shrinkage data are reported for representative materials: unfilled and resin composites, base-lining materials, and an impression material. Equilibrium shrinkage magnitudes ranged from 0.65%, for the impression material, to 7.9% for the unfilled resin. The kinetic behavior was approximately characterized by an overall time constant, ranging from 12.5 to 280 s, associated with an exponential growth curve, although the initial shrinkage was near-linear in time, for many materials, due to non-steady-state concentrations of polymer free-radicals. The test-specimen geometry facilitates rapid and essentially uniform cure and hence the determination of minimum possible time-constants at each ambient temperature and incident light-intensity. Study of hybrid glass-ionomer materials, without spurious dehydration effects, was also achieved.     

Electron probe microanalysis of ion exchange of selected elements between dentine and adhesive restorative materials

BACKGROUND: There have been numerous attempts to demonstrate the phenomenon of ion exchange between auto cure glass ionomer cements (GICs) and dentine. The purpose of this study was to employ an electron probe microanalysis (EPMA) technique to examine the interchange of elements between non-demineralized dentine and two types of restorative material, auto cure GICs and a resin composite. METHODS: Restorations of auto cure GICs (Riva Fast, Fuji IX Fast, Ketac Molar Quick and Fuji VII) and a bonded composite resin were placed in each of 10 recently extracted human third molar teeth. After two weeks the restorations were sectioned and prepared for EPMA. Percentage weights of calcium, phosphorus aluminum, strontium and fluoride were calculated in the restorations 200 microm from the restorative interface and 200 microm into the dentine at 5 microm intervals. RESULTS: There was evidence of calcium and phosphorus in all five auto cure GICs to a depth of 50 microm. Aluminum and strontium ions were also present in dentine except subjacent to Ketac Molar restorations. There was evidence of element transfer into composite resin and resin-bonded dentine. CONCLUSIONS: The findings of this paper support the concept of ion exchange as a bonding mechanism between auto cure GIC and dentine. Element penetration into tooth structure and GIC exceeded beyond the "ion exchange layer" observed in scanning electron microscopy studies. Penetration of calcium and phosphorus into composite resin from dentine likely occurred as a result of the self-etching process dissolving calcium and phosphorus and incorporating these elements into the hybrid layer. The presence of Al and Sr ions in dentine were likely to be associated with resin tags extending into the dentine.     

A long term study on residual monomer release from denture materials

The aim of this long term study was to investigate the release of residual monomer from different denture materials, throughout a 38 months time period after curing and storage in water Specimens made of four denture base resins (three heat polymerizing, one auto polymerizing) and one hard liner were subjected to residual monomer determination using gas liquid chromatography. The residual monomer estimation carried out on three occasions: one week, 12 months and 38 months after curing. The data obtained were analyzed using two-way Anova followed by Scheffe's test for post hoc multiple comparisons at alpha=0.05. Heat polymerized denture base acrylic resins showed less residual monomer than auto polymerized ones (p<0.001) and released no statistically significant amounts of monomer (p>0.05), during the 38 months storage time period. Auto polymerized denture materials, which had higher residual monomer content, released statistically significant amounts of monomer (p<0.001) during the first twelve months storage, but not during the last twenty six months period (p>0.05). Heat polymerized denture base acrylic resins released insignificant amounts of residual monomer during the storage period, whereas both the auto polymerized denture base resin and the hard liner released significant amounts of residual monomer during the initial storage time period but insignificant ones during the remainder of the storage period.     

An in vitro investigation of marginal dentine caries abutting composite resin and glass ionomer cement restorations

BACKGROUND: There are a number of studies citing the primary reason for replacing auto cure glass ionomer cements was due to recurrent caries. The purpose of this study was to use an in vitro model to measure caries at the dentine restoration interface of bonded composite resin and auto cure glass ionomer cement restorations and to measure the amount of surface degradation occurring in the restorative materials. METHODS: Specimens of auto cure glass ionomer cements (Riva Fast, Fuji IX Fast, Ketac Molar Quick and Fuji VII) and bonded composite resin restorations (Ice, SDI) were placed separately at the dentino-enamel junction of 10 recently extracted human third molar teeth, disinfected and placed into the overflow from a continuous culture of S. mutans for two weeks. Restorations were sectioned and prepared for scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Restoration tooth interfaces were photographed and the distance from the surface of the teeth to the surface of the restorations measured. EPMA of percentage weights of calcium, phosphorous and fluoride were made outwards from the restoration surface 130pm at a depth of 10 microm below the surface of the dentine. RESULTS: There were significant differences between the surface heights of composite resin, auto cure glass ionomer cements compared to teeth surfaces. Percentage weights of calcium and phosphorus levels were similar to non-demineralized dentine in the auto cure glass ionomer cement samples but there were significant reductions in mineral content of dentine adjacent to bonded composite resin restorations. Fluoride levels were mixed. CONCLUSIONS: This study shows that placing a bonded composite resin restoration into dentine affords little protection to the surrounding tooth from caries attack although insignificant degradation of the restorative surface occurs. Placing a glass ionomer cement restoration into dentine protects the surrounding tooth from caries but degradation of the restoration surface occurs.     

表面处理对托盘材料与加聚型硅橡胶结合强度的影响

目的研究喷砂及涂布粘结剂对不同托盘材料与硅橡胶结合强度的影响。方法制作不锈钢、自凝树脂、光固化树脂标准试件各40个,随机分组,每组同材质试件各10个,空白组:对试件不做处理;喷砂组:对试件进行喷砂处理;粘结剂组:对试件涂布托盘粘结剂;喷砂+粘结剂组:对试件喷砂后涂布粘结剂处理,与硅橡胶材料在测试装置中接触结合,行拉伸实验,记录结果,计算结合强度。结果 3种托盘材料均在喷砂加粘结剂处理时表现出最佳的结合强度;单独使用喷砂时,树脂材质托盘结合强度与空白组相比明显提高,而不锈钢托盘结合强度却下降明显;单独使用粘结剂时,与空白组相比,3种材质托盘结合强度均有显著提高。结论联合使用喷砂和粘结剂可显著提高托盘与硅橡胶结合强度,对树脂材料托盘单独使用粘结剂或喷砂有一定增加托盘结合强度的作用,金属托盘使用粘结剂亦可增加托盘结合强度。     

Wear characteristics and inhibition of enamel demineralization by resin‐based coating materials

In this study, wear and inhibition of enamel demineralization by resin‐based coating materials were investigated. Seven commercially available coating materials, with and without fillers, were used. A mechanical wear test was performed, and the specimens were then examined with a scanning electron microscope. Hardness and elastic modulus measurements for each material were obtained by nanoindentation testing. Thin layers of each material were applied on human enamel surfaces, which were subjected to alternating immersion in demineralizing and remineralizing solutions. The inhibition ability of enamel demineralization adjacent to the coating was estimated with depth‐dependent mechanical properties using the nanoindentation test. The non‐filled coating material showed significantly lower hardness, lower elastic modulus, and higher weight loss. There were no significant differences in weight loss among the six filled coating materials. After the alternating immersion protocol, the enamel specimens having application of coating materials with ion‐releasing ability were harder than those in the other groups in some locations 1–11 μm from the enamel surface and within 300 μm from the edge of the coating materials. In conclusion, clinical use of the resin‐based coating materials with ion‐releasing ability may prevent demineralization of exposed enamel adjacent to the coating during treatment.     

Comparison of bond strength of auto polymerizing, heat cure soft denture liners with denture base resin — An In Vitro study

Optimum bond strength between denture soft liner and denture base resin is very important for the success of any denture prosthesis. The tensile bond strength of two commercially available silicone-based heat cured (Molloplast B) and auto polymerizing (Mollosil) was compared with denture base material (trevalon). Molloplast B-trevalon bond in both un-polymerized (dough stage) and already polymerized forms were also compared. Lloyds Universal testing machine was used to test 60 samples. Molloplast B bond strength was greater than Mollosil soft denture liner; it was even greater when packed against trevalon in an un-polymerized form than an already polymerized trevalon using primo adhesive. Both the soft lining materials used are acceptable for clinical usage.     

Inhibiting microbial adhesion to denture base acrylic resin by titanium dioxide coating

Summary Mechanical cleaning of dentures is effective in preventing infections such as aspiration pneumonia and denture stomatitis. For denture wearers with a physical handicap and the elderly, however, mechanical cleaning can present problems. The aim of this study was to investigate the effect of coating denture base acrylic resin with titanium dioxide (TiO₂) in the inhibition of oral microbial adhesion. We prepared uniformly sized acrylic resin plates (10 mm × 10 mm × 0·5 mm), which were divided into two groups (a non‐coated group and a TiO₂‐coated group). The plates were immersed in cultured Streptococcus sanguinis or Candida albicans and incubated for 24 h. After incubation, each plate was washed to remove loosely adherent microorganisms, and then incubated for a further 24 h. Adenosine triphosphate (ATP) content of the microorganisms was evaluated using a reagent containing benzalkonium, which extracts intra‐cellular ATP. In addition, to determine biofilm formation, we also observed each plate by scanning electron microscopy (SEM). We found that the ATP content of both S. sanguinis and C. albicans was reduced by the TiO₂ coating (P = 0·000). Observation by SEM confirmed that the TiO₂ coating inhibited biofilm formation. The results indicate that a TiO₂ coating on a denture base acrylic resin inhibits adhesion of S. sanguinis and C. albicans.     

The Influence of Ceramic Surface Treatments on the Micro-shear Bond Strength of Composite Resin to IPS Empress 2

Purpose: An increasing demand for esthetic restorations has resulted in the development of new ceramic systems, but fracture of veneering ceramics still remains the primary cause of failure. Porcelain repair frequently involves replacement with composite resin, but the bond strength between composite resin and all‐ceramic coping materials has not been studied extensively. The purpose of this study was to evaluate the influence of different ceramic surface treatments on the micro‐shear bond strength of composite resin to IPS Empress 2 coping material. Materials and Methods: Sixteen 7 × 7 × 1 mm³ lithia disilicate‐based core ceramic plates were fabricated using the lost wax technique. The plates were divided into eight groups, and eight different surface treatments were performed: (1) no treatment (NT); (2) airborne‐particle abrasion with 50‐μm alumina particles (Al); (3) acid etching with 9.6% hydrofluoric acid for 1 min (HF); (4) silane coating (S); (5) AlHF; (6) AlS; (7) HFS; and (8) AlHFS. Then, ten composite resin cylinders (0.8‐mm diameter × 0.5‐mm height) were light‐polymerized onto the ceramic plates in each group. Each specimen was subjected to a shear load at a crosshead speed of 0.5 mm/min until fracture occurred. The fracture sites were examined with scanning electron microscopy (SEM) to determine the location of failure during debonding and to examine the surface treatment effects. One‐way analysis of variance (ANOVA) and multiple comparison (Dunnet T3) tests were used for statistical analysis of data. Results: The mean micro‐shear bond strength values (SD) in MPa were—NT: 4.10 (3.06), Al: 7.56 (4.11), HF: 14.04 (2.60), S: 14.58 (2.14), AlHF: 15.56 (3.36), AlS: 23.02 (4.17), HFS: 24.7 (4.43), AlHFS: 26.0 (3.71). ANOVA indicated the influence of surface treatment was significant (p < 0.0001). SEM analysis did not reveal entirely cohesive failure in any composite or ceramic. Conclusion: The micro‐shear bond strength of a composite resin to IPS Empress 2 was significantly different depending on the surface treatment method. Among the investigated methods, silane coating after airborne‐particle abrasion and etching was the most effective surface treatment in terms of bond strength increase.     

Effects of root dentin surface coating with all-in-one adhesive materials on biofilm adherence

OBJECTIVES: Sealing of exposed root dentinal surfaces with adhesive materials is expected to be a promising approach for preventing root dentin caries. The aim of this study was to evaluate the effects of surface coating with all-in-one adhesives on inhibiting Streptococcus mutans biofilm attachment. MATERIALS AND METHODS: Bovine root dentin was cut and ground with #600-grit SiC paper. Each of the three all-in-one adhesives, Hybrid Bond (HB), Reactmer Bond (RB) or Shake One (SO) was single-coated on the dentin surfaces according to the manufacturers' instructions. The dentin surface without coating served as the control. The surface roughness of the coated and non-coated dentin surfaces was recorded by means of laser microscope measurements. S. mutans artificial biofilms were then grown on the surface of each specimen in a microcosm for 20h. The amounts of bacteria and water insoluble glucan in the retained biofilm on the surface of the specimens were measured. All numerical data were statistically analyzed using one-way ANOVA & Tukey's HSD (p<0.05). RESULTS: All of the coated groups showed significantly lower susceptibility to biofilm attachment compared with the non-coated root dentin (p<0.05). Among the coated groups, SO showed the lowest susceptibility for biofilm formation. CONCLUSIONS: Three all-in-one adhesive materials could be effective for root surface coating. A fluoride-releasing adhesive, SO demonstrated the strongest potentiality in resisting biofilm formation.     

Effect of accelerated aging on the color stability of cemented laminate veneers

PURPOSE: The effect of the aging process on color stability of light-cure, dual-cure, and self-cure resin cements used for luting laminate veneers was investigated in this study. MATERIALS AND METHODS: Dyract Cem (self cure), Twinlook (dual cure), and En Force (light cure) cements, 0.30 mm thick, were polymerized on laminate veneers that were 13 mm in diameter and 0.50 mm thick in an A2 shade. Five specimens were made for each material. The specimens were subjected to an accelerated aging process in a Weather-Ometer for 900 hours. Spectrophotometric analyses were made after 300, 600, and 900 hours of accelerated aging time. Overall color difference (delta E*ab) was determined using the CIE-LAB system for measuring small color differences. Chroma changes (delta C*ab) and hue differences (delta H*ab) were also determined. delta E*ab, delta C*ab, and delta H*ab were analyzed by one-way analysis of variance, t test for dependent samples, and Tukey honestly significant difference (HSD) tests. RESULTS: delta E*ab values determined for the materials in this study varied in the acceptable range of 1.9 to 2.7. Different aging times caused no significant differences in delta E*ab, delta C*ab, or delta H*ab values for any of the materials. There were no significant differences in the amount of overall color change among the 3 resin cements at the same aging period. Twinlook material showed the greatest chroma change at each aging time. The greatest hue change was determined for Dyract Cem material. CONCLUSION: The light-cure resin cement tested can be proposed as a suitable material for luting laminate veneers, but long-term clinical studies are necessary to verify these experimental findings.     

Post-irradiation hardening of dual-cured and light-cured resin cements through machinable ceramics

PURPOSE: To evaluate the surface hardness (Knoop Hardness Number) of the thin layer in three light-cured and dual-cured resin cements irradiated through or not through 2.0 mm thick machinable ceramics. METHODS: A piece of adhesive polyethylene tape with a circular hole was positioned on the surface of the ceramic plate to control the cement layer (approximately 50 microm). The cement paste was placed on the ceramic surface within the circle. The ceramic plate with resin cement paste was placed on a clear micro cover glass over a zirconia ceramic block to obtain a flat surface, and the material was polymerized using a visible-light-curing unit. The surface hardness was recorded at a series of time intervals up to 5 days, starting from the end of a light-irradiation period. RESULTS: The hardness steadily increased with post-irradiation time and tended towards a maximum, usually reached after 1 or 2 days. In all cases, the increase in hardness was relatively rapid over the first 30 minutes and continued at a lower rate thereafter. The dual-cured resin cement for each material showed a significantly higher hardness value than the light-cured resin cement irradiated either through or not through ceramics at all post-irradiation times. The resin cements cured through ceramic for each material were significantly less hard compared with those cured not through ceramics at all post-irradiation times.     

Enhancement of adhesion between resin coating materials and resin cements

Resin coating technique is a unique method that improves the dentin bond strength of resin cements in indirect restorations. However, the weak link of a specimen bonded using the resin coating technique was reported to be the bonded interface between the resin coating material and resin cement. The purpose of this study, therefore, was to enhance the bonding performance between a resin coating material and a resin cement. Two light-cured flowable composites, Protect Liner F and Clearfil Flow FX, were used as coating materials, and two dual-cure composite materials, Panavia F 2.0 and Clearfil DC Core Automix, were used as resin cements. The ultimate tensile strength of each material and the microtensile bond strengths of the bonded specimens of resin coating material and resin cement were measured using a crosshead speed of 1.0 mm/min. Three-way ANOVA (p=0.05) revealed that the highest microtensile bond strength was obtained using a combination of Clearfil Flow FX and Clearfil DC Core Automix, and when the surface of the coating material was treated with ED Primer II. It was strongly suggested that materials with a higher ultimate tensile strength, when used in both resin coating and cementation, could enhance the bond strength between the two.     

Effect of Light‐Emitting Diode (LED) Curing Modes on Resin/Dentin Bond Strength

Purpose: This study aimed to compare the effect of three curing modes of a high‐powered curing‐light source on the shear bond strength and marginal gap of light‐ and dual‐cured adhesive resin cements to dentin. Materials and Methods: Twelve freshly extracted intact human mandibular molars were selected for this study and stored in the saline solution. Three of the axial surfaces of the teeth were prepared to obtain flat dentinal surfaces. Thirty‐six ceramic disks (4‐mm diameter, 2‐ mm thick) were constructed from a pressable glass‐ceramic (Vision). The discs were etched with hydrofluoric acid and primed, and then divided into two equal groups, groups I and II (n = 18 each). Two adhesive systems were used following manufacturer's instructions. The discs of group I were bonded to the conditioned dentin surface using adhesive resin (Rely X Veneer), and group II discs were bonded to dentin using Rely X ARC. For each group, the resin was cured using three modes (fast, ramp, pulse). Interfacial gap at the dentin/resin interface was measured at eight predetermined sites for each specimen using a stereomicroscope, and shear bond strength of the bonded specimens was carried out using a universal testing machine. Results: Ramp‐cured specimens recorded significantly higher mean shear bond strengths for both dual‐ and light‐polymerized resins than those with fast and pulse modes. Moreover, fewer interfacial gaps were found at the resin/dentin interface in association with ramp cure modes of both resins. Most failures were adhesive failures at the dentin–resin luting agent (RLA) interface in specimens polymerized using high‐powered LED fast or pulse modes, while a cohesive failure pattern within the resin was associated with the ramp‐curing mode. Conclusion: Within the limitations of this study, the shear bond strength of an RLA to dentin was found to be enhanced with light‐ or dual‐polymerized adhesive resin using an LED light in ramp mode, whereas shear bond strength was significantly lower when polymerized using LED in fast or pulse modes.     

树脂表面形态处理对义齿软衬材料粘结性能的影响

目的：探索一种增进硅橡胶软衬材料和基托粘结力的可靠方法,促进软衬材料的临床应用。方法：利用模具制作两组树脂基托板：平面基托板和有凸起的基托板,以silagum硅橡胶软衬材料为夹心,平板对平板、凸板对凸板分别制作＂三明治＂样结构,采用改良的＂L＂形拉伸撕脱试验测试两组试件的粘结功并记录撕脱方式,所得试验数据经统计学分析（a=0.05）。结果：凸起组的的粘结功明显大于平面组的粘结功,二者间的差异具有统计学意义（P〈0.05）。平面组的破坏形式以粘结性破坏为主;凸起组的破坏形式以内聚性破坏和混合性破坏为主。结论：改变树脂基托表面的形态增大接触面积及嵌合力可以增大硅橡胶软衬材料和丙烯酸树脂之间的粘结强度。