快速液压热聚合义齿基托材料的实验研究

目的 了解快速液压热聚合义齿基托材料的力学性能。方法 采用自行研制的新型液压自控牙用树脂聚合器和常规水浴两种方法加热固化义齿基托材料，进行挠度、抗弯曲强度、弹性模量、抗冲击强度及硬度的对比分折。结果 快速液压热聚合义齿基托材料的力学性能与水浴法相比无显著性差异，但可以明显缩短热处理时间且全过程自动完成。结论 快速新型液压自控牙用树脂聚合器简化了义齿制作的操作过程，明显缩短了热处理时间，可以准确快速制作出理想的义齿。     

不同聚合方式的基托体积稳定性的比较实验

通过快速水式液压自控牙用树脂聚合器热压灌注成型的义齿基托材料 ,在物理性能方面与常规水浴法及气压式多功能牙用树脂聚合器法者无显著性差异[1,2 ] 。作为一种新的工艺方法 ,必须考虑其成型后塑料的体积稳定性。本实验采用水式液压自控牙用树脂聚合器快速聚合聚甲基丙烯酸甲     

快速液压自控牙用树脂聚合器的临床应用研究

目的 :探讨快速液压自控牙用树脂聚合器在义齿制作中的临床应用效果。方法 :采用快速液压自控牙用树脂聚合器和常规水浴法分别制作可摘义齿并对其进行评估 ,同时测量义齿的临床调牙合高度。结果 :通过两种聚合方法固化的义齿在义齿的评估方面和可被临床戴用的数量上无显著性差异 ,两组中在需要调牙合的义齿件数上有显著性差异 ,水式液压组 <常规水浴法组。结论 :快速水式液压自控牙用树脂聚合器简化了义齿制作的操作过程 ,明显缩短了热处理时间 ,不增高咬合高度 ,从而减少了临床调牙合的时间 ,因此可明显缩短临床就诊的时间 ,提高临床工作效率 ,完全可以准确快速制作出理想的义齿     

聚甲基丙烯酸甲酯义齿基托材料聚合成型工艺的研究进展

本文着重介绍了聚甲基丙烯酸甲酯(PMMA)义齿基托材料的热压注塑成型、电热聚合固化、微波固化及快速自控气压和液压热聚合等固化成型模式的工作原理、方法、创新点及存在的缺陷等，初步探讨了PMMA义齿基托材料在其聚合成型工艺方面的研究进展。     

应用多用途牙用树脂聚合器临床体会

我科应用快速自控热处理塑料聚合器,对180件义齿进行塑料快速自控热处理,并对包埋脱蜡等方面作了改进,取得满意效果,现报道如下:1 材料与方法1.1 材料 多用途牙用树脂聚合器(第四军医大学口腔医学院研制),牙托粉与单体(上海齿科材料厂)。气压为中心供气。1.2 方法1.2.1 基牙预备、取模、取颌位关系、排牙制作要求同常规。牙排好后在蜡基托后缘左右两侧制一直径0.8～1.0cm、长3～5cm的蜡条与蜡基托相连,而后用喷灯喷光。1.2.2 包埋脱蜡,我们采用了分开式和封闭式     

快速自控热处理塑料制作义齿新工艺—临床应用研究

介绍一种快速自控热处理塑料制作义齿的新工艺，该新工艺系采用高压、高温密闭水浴热聚合器．小件修复体可在石膏模型上直接徐塑热凝塑料成形，不装盒；大基托、全口义齿按常规装盒，不上压榨器，直接置于聚合器中，以０．４～０．６ＭＰａ，１２０℃水浴热处理５～１０ｍｉｎ，可使热塑性塑料完全聚合，材料性能达到质量要求。该聚合器还可用于处理热固化复合树脂或自凝塑料，热处理过程自动控制，节能，无蒸气污染。     

新型液压自控牙用树脂聚合器研制与应用

目的：研制新型液压自控牙用树脂聚合器。方法：树脂修复体置于密闭聚合器中，旋紧其盖子使压力升至0.1MPa，然后自动电热加温，在聚合器内的水温升高的同时其压力亦在升高，水温每升高10℃，压力升高0.07-0.08MPa，当水温升至120℃时，压力升高至0.4-0.6MPa，维持3-10min，自动断水、排水，牙用树脂修复体聚合完成。结果：对常规装盒充填（无需机械夹紧），直接石膏包埋，灌注成形，涂塑成形塑料基托，硬质树脂制作间接贴面、嵌体、全冠、桥体以及硅橡胶制作义龈，可见光固化复合树脂二期处理等在压力水浴中进行快速热处理。结论：该聚合器采用直接液压，无需配用空压机加压，使用方便，可快速完成高质量塑料基托或硬质树脂等修复体，为口腔修复学增添一种新工艺和设备。     

微波聚合法对义齿基托树脂力学性能影响的研究

目的研究微波聚合方法对义齿基托树脂力学性能的影响。方法分别用微波聚合和水浴聚合方法制作63.0 mm×10.0 mm×2.5 mm的树脂试样各10个,经过10 000次冷热循环后,用电子万能试验机测量其弯曲强度和弯曲模量;同法制作同样规格的树脂试样各10个,用电子万能试验机测量其拉伸强度。结果微波法和水浴法制作的义齿基托树脂弯曲强度分别为（76.18±15.56）MPa和（73.06±13.01）MPa,差异无统计学意义（t=0.534 2,P〉0.05）;弯曲模量分别为（1 709.10±98.76）MPa和（1 699.21±90.23）MPa,差异无统计学意义（t=0.568 2,P〉0.05）;拉伸强度分别为（42.19±1.12）MPa和（44.35±1.22）MPa,差异无统计学意义（t=0.627 4,P〉0.05）。结论微波聚合方法制作的义齿基托树脂力学性能与水浴法制作的相当,但微波法聚合时间较水浴法明显缩短。     

不同聚合方法对基托树脂挠曲强度影响的实验研究

目的在实验室条件下比较2种义齿基托树脂经过4种聚合方法处理后基托树脂的挠曲强度，为临床选择适宜的聚合方法提供依据。方法用金属模具制备相同尺寸的蜡型96个，失蜡后使用2种品牌的义齿基托树脂填胶，用4种方法进行热处理使其固化，用万能力学实验机检测基托树脂的挠曲强度．用双因素方差分析和多重比较进行统计学处理。结果两种基托树脂的挠曲强度具有显著差异（P〈0.01），不同聚合方法间基托树脂的挠曲强度除电热法与一组水浴方法存在显著差异外．其余组间无显著差异。结论基托树脂的挠曲强度和材料的性能有关，不同聚合方法对基托树脂的挠曲强度没有显著影响。     

微波能固化义齿基托材料的实验性研究

目的 了解微波能加热处理义齿基托材料的力学性能和收缩变化。方法 采用微波能和水浴责任中方法加热固化义齿基托树脂。进行挠曲强度、硬度和收缩率的对比分析。结果 微波能固化的基托材料的力学性能与水溶法相比无显著性差异。但具有更好的尺寸精确性。结论 微波能是一种良好的固化义齿基托材料的热源。     

3种“活动矫治器”基托材料热压处理前后性能比较

目的:比较咬合诱导"活动矫治器"3 种基托材料的弯曲强度、冲击强度、粗糙度、弹性模量和色度,为临床选择材料提供依据.方法:以日进齿科材料有限公司生产的自然义齿基托聚合物Ⅱ型(以下简称日进)、日本株式会社而至生产的而至快速自凝基托树脂(以下简称而至)、上海二医张江生物材料有限公司生产的义齿基托树脂液Ⅱ型和上海医疗器械股份有限公司齿科材料厂生产的义齿基托树脂Ⅱ型(以下简称混合) 3 种基托材料为研究对象,对基托材料进行热压处理;测试挠曲强度、冲击强度、粗糙度及测试色度.测试结果用SPSS 12.0软件进行方差分析和Tamhane T2检验.结果:同一材料的"加压处理组"和"未加压处理组"比较,所有材料冲击强度的改变均有统计学意义,除此以外,个别材料挠曲强度和色度的改变有统计学意义.对于不同材料同一性能的比较,冲击强度:而至＞"混合"＞日进;挠曲强度:日进＞"混合"＞而至;弹性模量:日进＞"混合"＞而至;粗糙度:而至>日进>"混合".结论:热压处理可以作为提高活动矫治器的基托性能的手段;3 种材料比较,各有长短.医师应该结合治疗实际情况选择最合适的材料.     

Comparison of the bond strength of laser-sintered and cast base metal dental alloys to porcelain

OBJECTIVE: The purpose of this study was to compare shear bond strengths of cast Ni-Cr and Co-Cr alloys and the laser-sintered Co-Cr alloy to dental porcelain. METHODS: Dental porcelain was applied on two cast and one laser-sintered base metal alloy. Ten specimens were prepared for each group for bond strength comparison. ANOVA followed by Tukey HSD multiple comparison test (alpha=0.05) was used for statistical analysis. Fractured specimens were observed with a stereomicroscope to classify the type of failure after shear bond testing. RESULTS: While the mean shear bond strength was highest for the cast Ni-Cr metal-ceramic specimens (81.6+/-14.6MPa), the bond strength was not significantly different (P>0.05) from that for the cast Co-Cr metal-ceramic specimens (72.9+/-14.3MPa) and the laser-sintered Co-Cr metal-ceramic specimens (67.0+/-14.9MPa). All metal-ceramic specimens prepared from cast Ni-Cr and Co-Cr alloys exhibit a mixed mode of cohesive and adhesive failure, whereas five of the metal-ceramic specimens prepared from the laser-sintered Co-Cr alloy exhibited the mixed failure mode and five specimens exhibited adhesive failure in the porcelain. CONCLUSIONS: The new laser-sintering technique for Co-Cr alloy appears promising for dental applications, but additional studies of properties of the laser-sintered alloy and fit of castings prepared by this new technique are needed before its acceptance into dental laboratory practice. SIGNIFICANCE: Laser sintering of Co-Cr alloy seems to be an alternative technique to conventional casting of dental alloys for porcelain fused to metal restorations.     

加压固化法对全口基托适合度的影响

目的:探索用普通热凝树脂在注压法条件下制作出机械性能及适合度更好的试件及基托。方法:用热凝塑料,分别按传统水浴法及注压固化法制作试件及上半口义齿基托,与BPS专用树脂材料在注压条件下制作的试件及基托,进行抗弯强度、表面硬度及基托适合度测试。采用SPSS12ForWindows统计软件进行组间t检验。结果:热凝树脂采用注压法聚合成型与采用传统水浴法聚合的试件,在抗弯强度和表面硬度上有显著差异(P<0.05)。上半口基托在A、B、D、E点上的距离差异显著(P<0.05)。结论:普通热凝树脂通过注压法聚合成型,在表面硬度、抗弯强度及基托适合度上均有所提高。     

Effect of dental base metal alloys on IgE levels and some blood parameters

summary Despite the widespread use of nickelbased alloys, claims for safety of these alloys have not yet been accepted universally. The allergenic effects of nickel on dental patients and the potential toxic effects of nickel and beryllium on laboratory technicians continue to cause concern within the dental profession. The purpose of this study was to investigate immunoglobulin type E (IgE) values and some blood parameters of dental laboratory technicians who use dental base metal alloys. The following two groups were studied: 19 students who had been working with dental base metal alloys for two years; and 21 pre-clinical students who had never worked with dental base metal alloys. The latter group were used as a control. Blood specimens were taken from both groups and analysed using The Blood Counter. Total erythrocyte, thrombocyte, leukocyte, lymphocyte, granulocyte and monocyte counts were determined. Measurement of IgE was made with Coat-A-Count Total IgE IRMA. Blood and IgE measurements were repeated after 8 months. In the experimental group both erythrocyte and thrombocyte values were found to be statistically significantly decreased compared with the control group. No significant differences were found in lymphocyte and monocyte numbers between the initial and later measurements. There were no significance changes in IgE values for both groups. These results provide no evidence that dental base metal alloys (Ni, Cr, Be, Co) caused an increase in sensitization, during the period of the study.     

Forsus矫治恒牙期安氏Ⅱ类错(牙合)下颌后缩的牙弓及基骨弓宽度的变化

目的应用Forsus治疗已过生长发育高峰期安氏Ⅱ类错（牙合）下颌后缩恒牙期患者,探讨其牙弓及基骨弓宽度的变化。方法临床选择45例（男20例,女25例）恒牙期安氏Ⅱ类错（牙合）下颌后缩患者,年龄15-16．5岁。戴用Forsus矫治器前后制取牙颌模型,测量牙弓及基骨弓宽度。用Spss15．0统计软件对治疗前后的测量结果进行配对t检验。结果戴用Forsus矫治器前后牙弓及基骨弓宽度均增加。结论Forsus矫治器可用于牙弓狭窄患者的扩弓治疗,但扩弓后的远期疗效和稳定性还有待进一步研究。     

Superplastic forming of titanium alloy denture base

Ti-6Al-4V alloy has both excellent biocompatibility and superior mechanical properties. This Ti-6Al-4V can be deformed greatly and easily at the superplastic temperature of 800 degrees C to 900 degrees C. The superplastic forming of Ti-6Al-4V was made to apply to fabrication of denture base. Almost the same procedure as for dental casting mold was employed in producing the superplastic forming die by the improved phosphate bonded investment. In the pressure vessel of heat resistant alloy, Ti-6Al-4V plate was formed superplastically on the die by argon gas pressure at 850 degrees C. The fit of superplactic forming Ti-6Al-4V denture base was better than that of casting Co-Cr alloy denture bases. The Ti-6Al-4V alloy might react a little with the die. Because micro Vikers hardness of the cross-section did not go up too much near the surfaces. Even just after being formed, the surfaces were much smoother than that of Co-Cr alloy casting. The tensile strength and yield strength of superplastic forming Ti-6Al-4V were higher than those of Co-Cr castings. The elongation was about 10%. These results show that superplastic forming of Ti-6Al-4V would be suitable for a denture base.     

Relationship between dental crowding,skeletal base lengths,and dentofacial measurements

ObjectivesThe objectives of this study were to study the correlation between dental crowding, skeletal base lengths, and dentofacial measurements.Materials and methodsPretreatment dental casts and lateral cephalograms of randomly selected 45 Class I orthodontic cases divided into two groups according to the severity of mandibular crowding were evaluated. Group 1 comprised 15 patients with mandibular crowding less than 3 mm while group 2 comprised 30 patients with mandibular crowding of 3 mm or more. Maxillary and mandibular dental crowding and dentofacial measurements were compared between the two groups. For correlations the whole sample was combined to a single group where crowding was used as a continuous variable.ResultsThe only significant difference (p = 0.000) between the two groups was in the amount of dental crowding in the lower arch. Direct moderate correlation (r = 0.45; p = 0.002) between maxillary crowding and mandibular crowding, direct high correlation (r = 0.68; p = 0.000) between maxillary base length (Co-A) and mandibular base length (Co-Gn) and also direct high correlation (r = 0.74; p = 0.000) between maxillary base position (SNA angle) and mandibular base position (SNB angle) were detected. Correlation between maxillary incisor position and facial vertical dimension measured by the MP to SN angle showed inverse moderate correlation. Correlation between mandibular incisor position and the anteroposterior jaw relationship measured by the ANB angle showed direct moderate correlation.ConclusionsResults showed the presence of correlation between the skeletal dimensions and the absence of correlation between dental crowding and the same measurements. Results suggest that dental crowding is independent of the skeletal measurements.     

Effect of carbamide peroxide bleaching on the shear bond strength of composite to dental bonding agent enhanced enamel

STATEMENT OF PROBLEM: Carbamide peroxide bleaching has been implicated in adversely affecting the bond strength of composite to enamel. PURPOSE: This in vitro study evaluated the effect of 3 dental bonding agents (OptiBond, All-Bond 2, One-Step) on the shear bond strength of a hybrid composite to enamel which was treated by a 10% carbamide peroxide bleaching system. MATERIAL AND METHODS: Cylinders of composite were bonded to carbamide peroxide-treated enamel on extracted human teeth using 3 dental bonding agents. After thermocycling, shear bond strengths were determined with a universal testing machine. RESULTS: OptiBond aided bond strengths were 23.7 +/- 5.6 MPa to bleached and 19.6 +/- 2.9 MPa to unbleached enamel. For All-Bond 2, bleached enamel exhibited bond strengths of 14.9 +/- 4.0 MPa and unbleached enamel exhibited a bond strength value of 20. 4 +/- 2.3 MPa. The composite bond strength for One-Step was 13.6 +/- 5.9 MPa to bleached and 23.0 +/- 3.9 MPa to unbleached enamel. There was no statistical difference between OptiBond (alcohol base) aided bond strengths for bleached and unbleached enamel; however, the bond strength of composite to bleached enamel with All-Bond 2 or One-Step (acetone base) was significantly lower than unbleached controls. CONCLUSION: The effect of bonding agent usage on composite bond strength to enamel bleached with a particular carbamide peroxide was dependent on the bonding agent used.