三种丙烯酸树脂牙和丙烯酸牙托粉的结合强度实验研究

为了探求人造牙从基托上脱落下来的原因,本文作者对三种丙烯酸树脂牙和三种丙烯酸牙托粉的拉伸结合强度和剪切结合强度进行了测试,结果表明,材料和不同品牌材料的匹配都会影响人造牙与基托的结合强度;塑料牙盖嵴面打磨粗糙后,可显著增强塑料牙与基托树脂的结合强度。     

Assessment of shear bond strength between three denture reline materials and a denture base acrylic resin

PURPOSE: This study reports the effect of five surface treatments on the bond strength established between three denture reline materials and a denture base resin. MATERIALS AND METHODS: Cylindric columns of denture reline materials were bonded to columns of denture base resins that received one of the surface treatments: application of dichloromethane, the monomer of the denture base resin, the recommended bonding agent or the monomer of the denture reline material, polishing with 240-grit silicone carbide paper, and air abrasion. A control group without surface treatment was included for each material. Specimens were immersed in water for 1 day and then thermocycled. The strength at which the bond failed under shear was recorded. RESULTS: None of the surface treatments significantly improved the bond strength of Kooliner. Triad bonding agent and denture base monomer applications most significantly improved the bond strengths of Triad and GC reline, respectively. CONCLUSION: Triad bonding agent and denture base monomer should be used in conjunction with Triad and GC reline, respectively, when relining a denture base resin.     

义齿清洁剂对热固化型基托树脂物理及机械性能的影响

目的 评价5种义齿清洁剂对热固化型基托树脂颜色稳定性、表面粗糙度、弯曲强度的影响。方法 热固化型基托树脂试样浸泡于保丽净、澳多—C、Protefix、0.2%葡萄糖酸氯己定、雅克菱义齿清洁剂以及蒸馏水中,后测量试样颜色的改变(ΔE)、粗糙度值、弯曲强度。结果 0.2%葡萄糖酸氯己定、雅克菱义齿清洁剂的颜色改变较对照组显著较大;将ΔE值用NBS（美国国家标准局）单位来表示,所有组对应的人色差感觉程度均为感觉轻微。对于表面粗糙度和弯曲强度,不同浸泡处理组间无统计学差异。结论 热固化型基托树脂使用义齿清洁剂180 d后,0.2%葡萄糖酸氯己定、雅克菱浸泡后颜色稳定性较差,但为临床可接受。保丽净、澳多—C、Protefix对材料均无影响。     

Effect of surface treatments on the bond strength between composite resin and acrylic resin denture teeth

PURPOSE: This investigation studied the effects of 3 surface treatments on the shear bond strength of a light-activated composite resin bonded to acrylic resin denture teeth. MATERIALS AND METHODS: The occlusal surfaces of 30 acrylic resin denture teeth were ground flat with up to 400-grit silicon carbide paper. Three different surface treatments were evaluated: (1) the flat ground surfaces were primed with methyl methacrylate (MMA) monomer for 180 seconds; (2) light-cured adhesive resin was applied and light polymerized according to the manufacturer's instructions; and (3) treatment 1 followed by treatment 2. The composite resin was packed on the prepared surfaces using a split mold. The interface between tooth and composite was loaded at a cross-head speed of 0.5 mm/min until failure. RESULTS: Analysis of variance indicated significant differences between the surface treatments. Results of mean comparisons using Tukey's test showed that significantly higher shear bond strengths were developed by bonding composite resin to the surfaces that were previously treated with MMA and then with the bonding agent when compared to the other treatments. CONCLUSION: Combined surface treatment of MMA monomer followed by application of light-cured adhesive resin provided the highest shear bond strength between composite resin and acrylic resin denture teeth.     

Effect of incorporation of 2-tert-butylaminoethyl methacrylate on flexural strength of a denture base acrylic resin

Polymethyl methacrylate (PMMA) resins have commonly been used as a denture base material. However, denture bases may act as a reservoir for microorganisms and contribute to oral diseases in denture wearers. It is hypothesized that the 2-tertbutylaminoethyl methacrylate (TBAEMA) incorporated to acrylic resins should have antimicrobial activity related to the presence of amino groups on acrylic resin surface.

Objectives

The objectives of this study were to evaluate the presence of amino groups on acrylic resin surface and the influence on flexural strength after incorporation of TBAEMA.

Material and Methods

Six groups were divided according to the concentration of TBAEMA incorporated to acrylic resin (Lucitone 550): 0, 0.5, 1.0, 1.5, 1.75 and 2%. Specimens surface were evaluated by electron Spectroscopy for Chemical Analysis (ESCA) to detect the presence of amino groups, represented by nitrogen ratios. Flexural strength of the specimens was tested and results were analyzed by ANOVA and Tukey''s test (α=0.05).

Results

Different nitrogen ratios were observed on specimen surfaces: 0, 0.13, 0.74, 0.66, 0.92 and 0.33% for groups 0, 0.5, 1.0, 1.5, 1.75, and 2%, respectively. Significant differences were found for flexural strength (p<0.001). The mean flexural strength values were 98.3±3.9, 93.3±3.2, 83.9±2.1, 82.8±5.2, 71.2±5.1 and 17.3±3.2 MPa for groups 0, 0.5, 1.0, 1.5, 1.75, and 2%, respectively.

Conclusion

Within the limitations of this study, the incorporation of TBAEMA results in the presence of the potentially antimicrobial amino groups on specimen surfaces, but affect the flexural strength, depending on the concentration of TBAEMA.     

Impact strength of acrylic denture base resin reinforced with woven glass fiber

This study investigated the effect of the number and position of woven glass fibers in denture base resin matrix on its impact strength. Test specimens were reinforced with woven glass fiber 0.5, 1.0, or 1.5 mm below the surface. The impact strength was tested using an Izod-type impact tester with an impact speed of 335 cm/s, which simulates dropping the denture, and using a flywheel-type impact tester with a two-point support at 13.5 and 75.0 cm/s, which simulates the chewing. The woven glass fibers had a strengthening effect in all tests, and the impact resistance was further improved when the woven glass fibers were positioned more superficially in the resin. The results suggest that woven glass fiber is an effective reinforcement in denture base resin.     

Tensile bond strength of acrylic resin denture teeth to a microwave- or heat-processed denture base

STATEMENT OF PROBLEM: Fracture of acrylic resin prosthetic teeth from acrylic resin denture bases can be a problem for some patients. The optimal combination of acrylic resin denture tooth, denture base material, and processing method is not known. Purpose. The objective of this study was to compare the tensile bond strengths of heat- and microwave-polymerized acrylic resins among 4 types of acrylic resin denture teeth. MATERIAL AND METHODS: Heat-polymerized (Lucitone 199) and microwave-polymerized (Acron MC) acrylic resins were used. Four types of acrylic resin denture teeth (IPN, SLM, Vitapan, and SR-Orthotyp-PE) were milled to a fixed diameter according to ADA specification no. 15. Ten specimens of each tooth type were processed to each of the denture base materials according to the manufacturers' instructions. Ten additional resin control specimens without teeth also were fabricated. Specimens were thermocycled and tested for strength until fracture with a custom alignment device. Data were analyzed with analysis of variance and Duncan's multiple range test. A scanning electron microscope was used to identify adhesive and cohesive failures within debonded specimens. RESULTS: The mean force required to fracture the specimens ranged from 5.3 +/- 3.01 to 21.6 +/- 5.2 MPa for the microwave-polymerized base and 11.2 +/- 3.0 to 39.1 +/- 5.1 MPa for the heat-polymerized base. The most common failure was cohesive within the denture tooth. With each base material, Orthotyp and IPN teeth exhibited the highest bond strengths; SLM and Orthotyp bond strengths were similar. In general, heat-polymerized groups failed cohesively within the denture base resin or the tooth, and microwave-polymerized groups failed adhesively at either the ridge lap or occlusal surface of the denture tooth. CONCLUSION: Within the limitations of this study, the results suggest that the type of denture base material and denture tooth selected for use may influence the tensile bond strength of the tooth to the base. Selection of more compatible combinations of base and resin teeth may reduce the number of prosthesis fractures and resultant repairs.     

The significance of adhesive denture base resin

This article reviews the problems that occur at the metal-resin interface of removable partial dentures. The absence of a chemical bond between the denture base resin and the base metal alloy results in a potential for microleakage and bond failure at the junction. Recent development of a denture base resin that incorporates 4-META has been reported, primarily in the Japanese dental literature. The primary advantage of the 4-META resin system involves its bond to base metal alloys used in removable partial prosthodontics.     

The bond strength of a visible light-cured reline resin to acrylic resin denture base material

The introduction of Triad visible light-cured denture resin has led to several applications. Among them is direct intraoral relining of complete and partial dentures. This study investigated the bonding characteristics of Triad reline resin to four commonly used heat-cured denture base resins. The shear and tensile bond strengths of Triad resin and four denture base resins were determined and compared with intact tensile strengths. The findings of this study indicate that the bond strength of Triad resin to denture base resin is sufficiently high to suggest its clinical applicability.     

丙烯酸酯类义齿基托材料的研究进展

本文介绍了使用新型热聚合器、树脂上光剂、化学清洁剂改善热固化型丙烯酸酯类义齿基托表面光洁度和在基托材料中加入抑菌剂以减少基托表面细菌粘附的方法。在基托中加入玻璃纤维、超高分子量聚乙烯纤维等提高基托机械强度的材料研究新进展。     

Effect of storage duration on the hardness and tensile bond strength of silicone- and acrylic resin-based resilient denture liners to a processed denture base acrylic resin

STATEMENT OF PROBLEM: Two potential problems commonly identified with a denture base incorporating a resilient liner are a failure of the bond between the acrylic resin and resilient liner material and a loss of resiliency of the resilient liner material over time. PURPOSE: This investigation evaluated the effect of storage duration on the tensile bond strength and hardness of acrylic resin- and silicone-based resilient liners that were either heat- or autopolymerized onto denture base acrylic resin. MATERIAL AND METHODS: The denture liners investigated were a definitive acrylic resin-based heat-polymerized (Vertex Soft), interim acrylic resin-based autopolymerized (Coe-Soft), definitive silicone-based heat-polymerized (Molloplast-B), and definitive silicone-based autopolymerized (Mollosil Plus) resilient liner. The resilient liners were processed according to manufacturers' instructions. The resilient liner specimens for tensile bond strength testing (n=10) were 10 x 10 x 3 mm and were processed between 2 polymethyl methacrylate (PMMA) (Meliodent) blocks (40 x 10 x 10 mm). The resilient liner specimens for hardness testing (n=10) were 20 mm in diameter and 12 mm in height. Specimen shape and liner thickness were standardized. Specimens were stored for 1 day, 1 week, or 1, 3, or 6 months in water at 37 degrees C. Tensile bond strength was measured in a universal testing machine at a crosshead speed of 20 mm/min, and hardness was measured using a Shore A durometer. Two-way ANOVA and Tukey HSD tests were used to analyze the data (alpha=.05). RESULTS: The results indicated that there were significant differences both in the hardness and bond strength values of resilient liner materials. The definitive silicone-based heat-polymerized (Molloplast-B) resilient liner had significantly higher bond strength and lower hardness values than the others. Prolonged exposure to water produced significantly higher hardness values and lower bond strength values. CONCLUSIONS: Within the limitations of this in vitro study, specimens of resilient liners immersed in water demonstrated significantly (P<.001) lower bond strength values and higher hardness values over time.     

Bond strength of 4-META acrylic resin denture base to cobalt chromium alloy

This study was designed to compare the bond strength of a conventional poly(methyl methacrylate) acrylic resin denture base (Lucitone 199) with a recently developed acrylic resin base containing 4-META (Meta-Dent) to CoCr metal alloy by using various designs representative of clinical situations. The mechanical bond strength of Lucitone 199 resin was compared with the chemical and combination chemical and mechanical bond strength of Meta-Dent resin. The following conclusions may be extrapolated from the results. 1. The highest bond strength was observed between Meta-Dent resin and the plain flat metal plate. 2. The second highest bond strength was observed between Meta-Dent resin and the flat metal plate with two posts. 3. The lowest bond strengths were observed between Meta-Dent resin and the samples containing mesh retentive mechanisms. 4. The mean bond strength of Lucitone 199 resin was highest for the flat metal plate with two posts, followed by the large mesh. Bond strength with the small-mesh samples was lowest. These differences were not statistically significant. 5. The mean bond strengths of Meta-Dent resin to flat metal plates with or without posts was significantly higher than any of the Lucitone 199 resin metal bond strengths, to the 99% confidence level. Additional studies will be necessary to confirm the validity of these conclusions with respect to clinical removable partial dentures. Longitudinal investigations will be required to reveal clinical performance of these resin systems.     

Effect of relining, water storage and cyclic loading on the flexural strength of a denture base acrylic resin

OBJECTIVES: This study investigated the effect of relining, water storage and cyclic loading on the ultimate flexural strength (FS(U)) and on the flexural strength at the proportional limit (FS(Pl)) of a denture base acrylic resin (Lucitone 550-L). METHODS: Rectangular bars of L were made (64 mm x 10 mm x 2 mm) and relined (1.3mm) with four relining resins (Kooliner-K, Ufi Gel Hard-UGH, Tokuso Rebase Fast-TR and New Truliner-NT). In addition, specimens relined with L and intact L specimens were made (64 mm x 10 mm x 3.3 mm). A three-point flexural test was applied on the specimens (n=10) after (1) polymerization; (2) water storage (30 days); (3) cyclic loading (10,000 cycles at 5 Hz) and (4) water storage (30 days)+cyclic loading. Data (MPa) were analyzed with three-way ANOVA and Tukey's HSD tests (alpha=0.05). To test for a possible correlation between FS(U) and FS(Pl), a linear regression coefficient "r" was calculated. RESULTS: After water storage, L-UGH and L-TR demonstrated an increased FS(U) (41.49-50.64 MPa and 49.95-57.36 MPa, respectively) (P<0.05). Only L-TR demonstrated an increased FS(Pl) (20.58-24.21 MPa) after water storage (P<0.05). L-L had the highest FS(U) (between 78.57 and 85.09 MPa) and FS(Pl) (between 31.30 and 34.17 MPa) (P<0.05). The cyclic loading decreased the FS(U) and FS(Pl) of all materials (P<0.05). Regression analysis showed a strong linear correlation between the two variables (r=0.941). CONCLUSIONS: Water storage improved the FS(U) of L-UGH and L-TR and the FS(Pl) of L-TR. L-L produced the highest FS(U) and FS(Pl). The FS(U) and FS(Pl) of all materials were detrimentally influenced by cyclic loading.