Ti-6Al-4V义齿基托超塑成形及其精确性分析

对Ti-6Al-4V义齿基托超塑成形进行了实验研究,对其精确性进行了分析。将ZrO2-TiO2陶瓷粉末与聚乙烯醇（PVA）溶液进行混合,压模成形后,在1300℃时无压烧结3h,制成与口腔形状吻合的、具有足够强度的超塑成形用陶瓷模具。在925℃时,采用超塑性胀形法可将0．8mm厚的Ti-6Al-4V薄板成形为义齿基托。对超塑成形制件的尺寸进行测量,得出的平均厚度与坯料相比减小了约21％。采用陶瓷圆柱压痕方法测量的结果表明,热膨胀对义齿基托的尺寸精度影响不大,另外,义齿基托制件的厚度分布较均匀,不影响义齿基托与口腔的贴合,可满足普通临床需要。     

Evaluation of thermal conductivity and esthetic quality of denture base resin composites with acrylic polymer and nanodiamonds

The effect on the thermal conductivity and esthetic quality of acrylic denture base resins due to the addition of surface-carboxylated nanodiamonds (NDs) was evaluated using direct heat flux measurement and spectrophotometric measurement, respectively. The addition of NDs to the denture resin improved its thermal conductivity, which was highly depended on the ND content. The thermal conductivity increased significantly upon the addition of a small amount of NDs, followed by a gradual decrease with increasing ND content. The influence of the ND content on the thermal conductivity of the ND-impregnated resins was explained via experimental results and the theory of phonon scattering. Furthermore, changes in the appearance of the denture base resins caused by ND impregnation were observed to assess their esthetic qualities. The color changes in the resins with low ND contents were found to be minor. Therefore, the improved thermal conductivity and the retention of appearance of the resin can be simultaneously achieved by the addition of a small amount of NDs.     

Fiber‐reinforced nanopigmented poly(methyl methacrylate) as improved denture base

Nanopigmented and fiber‐reinforced poly (methyl methacrylate) (PMMA) were synthesized for denture bases, by incorporating E‐glass fibers, flock fibers, or polyethylene fibers into the PMMA powder formulation to improve the flexural behavior and porosity; decreasing the Candida albicans adherence and being noncytotoxic. The commercial acrylic resin, Lucitone 199 was used as a control group. Scanning electron microscopy analysis was performed to the PMMA particles and the reinforcing fibers. Flexural strength increased by adding E‐glass fibers in the PMMA powder as compared to flock and polyethylene fibers. The reinforced PMMA with flock fibers showed the lower porosity even smaller than Lucitone 199. The synthesized PMMA and the fiber reinforced nanopigmented PMMA groups reduced significantly the C. albicans adherence when compared to the commercial acrylic resin. All the tested groups were found to be nontoxic materials after being in contact with mouse fibroblast culture during 24 h, showing that these novel nanostructured composites are suitable for producing adequate and nontoxic reinforced materials with antimicrobial properties for dentistry applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

全冠义齿网格过渡算法研究与应用

针对全冠义齿数字化设计时外冠和内冠过渡融合的问题,提出了一种新的网格过渡算法。首先提取外冠和内冠网格边界进行桥接形成封闭孔洞;然后根据定义的三角片插入规则插入新的三角片填充孔洞,构造初始过渡网格;最后投影到由边界顶点插值得到的隐式曲面上,投影点构成新的过渡网格,将其与外冠和内冠拓扑合并形成完整的全冠义齿修复体。用过渡算法得到的网格面片分布均匀,三角片质量较好,而且过渡边界光顺自然,具有较好的连续性。     

舌侧集中总义齿患者满意度的调查分析

目的评估舌侧集中总义齿患者的满意度。方法将10例拟做总义齿的无牙颌患者按随机数字表法分为2组：A组和B组,每组5例。2组患者均先后接受两副义齿（一副是舌侧集中总义齿,另一副是解剖式双侧平衡总义齿）干预。A组在第1阶段接受舌侧集中干预,第2阶段接受解剖式双侧平衡干预;B组在第1阶段接受解剖式双侧平衡干预,第2阶段接受舌侧集中干预。采用全口义齿满意度问卷调查表对10例患者分别戴用舌侧集中和解剖式双侧平衡总义齿8周后的满意度进行调查。全口义齿满意度问卷调查表中的每项内容采用视觉模拟评分法（VAS）量化。结果舌侧集中的咀嚼能力、稳固性VAS评分值均明显高于解剖式双侧平衡,差异均有统计学意义（均P〈0.05）。舌侧集中的美观性、语音功能、舒适性VAS评分值与解剖式双侧平衡比较差异均无统计学意义（均P〉0.05）。结论舌侧集中总义齿患者具有较高咀嚼能力和稳固性的满意度。     

Tongue pressure recordings during speech using complete denture

This paper describes an original experimental procedure to measure mechanical interactions between tongue and teeth during speech production. Using edentulous people as subjects, pressure transducers are inserted in their complete denture duplicate. Physiology is respected during sound and pressure recording as with standard complete denture. Original calibration device is also described in order to know what kind of information can be extracted from the data. The measurements are realized in different experimental conditions in order to remove the auditory and the orosensory feedbacks. Then the first results of the pilot study are presented.     

Effects of chairside polishing and brushing on surface roughness of acrylic denture base resins

The effects of 3 chairside polishing kits and mechanical brushing on the surface roughness of 3 different acrylic denture base resins were compared. Acrylic denture base resins (auto-polymerizing, heat-polymerizing, injected heat-polymerizing resins) were examined after a tungsten carbide bur, and after chairside polishing using 3 polishing kits and pumice. The specimens were subjected to mechanical brushing using a wear tester to simulate 30 000 strokes of brushing. The surface roughness of the acrylic denture base resin specimens was measured using a contact profilometer. After the test, the random polished acrylic resins were evaluated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Acrylic denture base resins polished using the 3 types of polishing kits had a smoother surface than those finished with the tungsten carbide bur (p<0.05). The surface of the resin polished by a TC cutter exceeded the R _a of 0.2 μm (p<0.05). The auto-polymerizing resin showed a significantly higher surface roughness than the heat-polymerizing resin and injected heat-polymerizing resin (p>0.05). In the case of polishing step wise, there was almost no change in surface roughness after brushing (p>0.05).     

Effect of thermocycling and treatment with monomer on mechanical properties of soft denture liner Molloplast B

Bonding between soft liner (Molloplast B) and denture base resins (poly(methyl methacrylate)) is a significant problem. Surface treatment with some adhesives of denture base resins increase bonding between these two materials. The purpose of this study was to investigate the effect of thermocycling and of surface treatment with MMA monomer on the mechanical properties of the silicone-based soft liner. A silicone soft lining material (heat-polymerized silicone rubber) and heat-polymerized denture base resin, PMMA, were chosen for this investigation. Transient mechanical and dynamic mechanical properties changed with monomer treatment and/or thermocycling.