弹性树脂固位体在PMMA基托联合应用改善传统活动义齿的美观

目的：设计联合义齿改善传统活动义齿易显露金属卡环，影响患美观问题。方法：用弹性树脂制作固位体，聚甲基丙烯酸（PMMA）树脂制作基托与人工牙，在弹性固位体上制作固位形加强两种材料的结合，联合应用弹性树脂与PMMA树脂，设计联合义齿，修复缺牙患56例。结果：联合义齿获得了良好的美观效果，并改善了义齿的固位与应力分布，防止食物嵌塞，易于修理。结论：联合义齿结合了弹性树脂PMMA树脂的优点，是一种值得推广的活动义齿设计。     

弹性树脂与铸造支架在义齿修复中的应用(附28例报告)

目的设计一种联合义齿以解决传统可摘局部义齿易显露金属卡环影响美观的问题.方法用弹性树脂制作可摘局部义齿的基托及唇侧固位体,结合铸造支架,制作联合可摘局部义齿,修复28例因多数后牙缺失或前后牙均有缺失须在前牙区设计固位体的病例,行联合义齿修复.结果联合可摘局部义齿具有良好的美观效果及咀嚼功能.结论联合可摘局部义齿兼有弹性树脂和铸造支架的优点,可作为临床上选用的一种修复体.     

隐形义齿与铸造支架联合修复双端游离缺失的临床探讨

目的：探讨采用隐形义齿与铸造支架联合修复双端游离缺失的临床效果。方法：采用弹性树脂做基托和唇（颊）侧固位体,缺失区和支托采用铸造支架,制作修复件27件,修复双端游离缺失23例。患者戴用1年后进行临床观察。结果：弹性树脂与铸造支架联合义齿的美观舒适感、食物嵌塞、基牙情况等较传统活动义齿均有明显改善。结论：弹性树脂与铸造支架联合义齿修复双端游离缺失是一种解决游离端缺失修复的好方法。     

弹性树脂结合铸造支架可摘义齿修复牙周病患者缺牙的临床评价

目的：探讨弹性树脂与铸造支架联合修复牙周病患者缺牙的临床效果。方法：采用弹性树脂做唇（颊）侧基托及前牙、前磨牙唇（颊）侧固位体,后牙及舌（腭）侧采用铸造支架,设计联合可摘局部义齿,修复28例牙周病缺牙患者,共35件修复体,戴用1年后进行临床评价。结果：弹性树脂结合铸造支架可摘义齿在美观舒适性、固位力、咀嚼功能、食物嵌塞、基牙情况等方面较传统义齿有明显改善。结论：将弹性树脂与铸造支架结合起来修复牙周病缺牙,能很好的解决其美观和功能的问题,是一种较好的修复方法。     

铸造支架结合弹性树脂可摘义齿修复的临床观察

目的：探讨弹性树脂与铸造支架联合修复牙列缺损的临床效果。方法：132例缺牙患者,共187件联合式义齿修复体。Kennedy一类修复36件,Kennedy二类修复27件,Kennedy三类修复91件,Kennedy四类修复33件。通过1～4年的观察,从形态和功能、固定和稳定、颜色和美观以及对义齿的满意程度进行临床效果评价。结果：187件义齿中160件具有良好的美观效果,颜色满意,感觉舒适,满意率达85.56%。结论：弹性树脂与铸造支架结合式义齿是一种美观、舒适、对基牙预备较少的可摘局部义齿修复形式,但Kennedy一类、二类、四类缺损应谨慎选用。     

弹性义齿在过渡性修复中的应用初探

过渡性修复是为了某些口颌系统疾病的治疗或为明确诊断、美观和改善咀嚼功能,同时也为最终修复体设计和制作,提供更佳治疗方案而制作的临时性修复[1]。修复体只是暂时性的,不能长期戴用。弹性义齿便是用本身带有弹性的基托树脂替代了传统可摘义齿的金属卡环,具美观、舒适、耐磨     

带圈顶盖附着体在可摘义齿中的应用

具有伸缩弹性的固位体在活动义齿中应用的优点在很多文献中均有报道。因为这种固位体不仅可产生足够的固位力、均匀分散压力,而且改进了传统卡环影响美观的弊病。本文介绍的这种带圈顶盖就是一种改良了的弹性固位体。它独特之处于顶盖与它的上层结构之间存在一个富有弹性的小橡皮圈,这种圈状物放     

齿科树脂基托热压注塑成型机的研制及应用

目的 研制齿科树脂基托热压注塑盛开时机,探讨应用前景。方法 由压机部件、液压部件和电器控制部件三部分组成齿科树脂基托热压注塑成型机,运用ＰＭＭＡ试量口嘶托。结果 使用ＰＭＭＡ树脂由齿科树脂基托注塑成型机制成全口义齿基托。结论 齿科树脂基托热压注塑成型机方便实用,初步观察义齿基托制品性能良好。     

弹性树脂卡环铸造部件结合式义齿的临床应用

牙列缺损是口腔修复临床的常见和多发性缺损畸形[1]。在牙列缺损的诸多修复方法中，活动义齿是牙列缺损最常见的方法，但常规可摘局部义齿，存在美观和发音上的不足，许多患者难以接受。弹性树脂卡环铸造部件结合式义齿，是应用弹性树脂材料制作前牙及双尖牙区卡环、基托，而连接杆、支托、磨牙区卡环及小连接体等非弹性部位，采用铸造方法制作的可摘局部义齿。作者从1998年到2000年，对60例患者62件义齿用此方法修复，临床应用证明，能获得满意的修复效果。现介绍如下：1.材料和方法1.1一般资料修复60例患者共62件义齿，男性24例，女性36例…     

铸造牙间卡用于可摘局部义齿修复

目的:改善铸造可摘局部义齿固位体的美观性,减轻颊侧固位体的异物感。方法:在两基牙间的颊、龈外展隙内设置牙间卡(发夹卡)。结果:固位体金属外露少、隐蔽性好,美观明显改善,同时,体积小,无异物感。对34例不同牙缺失患者的使用,经1~2年观察,修复体固位良好,基牙未见松动和移位。结论:铸造牙间卡在美观、制作和异物感等方面明显优于常规铸造冠外固位体。     

Clinical performance of a light-cured denture base material compared to polymethylmethacrylate—a randomized clinical study

The aim of this study was to evaluate the clinical long-term performance of a visible light-cured resin (VLCR) denture base material and to compare it to a well-established polymethylmethacrylate (PMMA)-based denture acrylic in a randomized split-mouth clinical long-term study. One hundred removable partial dentures in 90 patients, with at least two saddles each, were investigated. One saddle was made of VLCR, while the other was made of PMMA at random. Plaque adhesion, tissue reaction, and technical parameters of the dentures were assessed 6, 12, and 18 months after treatment. Statistical analysis was performed using the Wilcoxon rank-sum test. Though VLCR showed higher plaque adhesion than PMMA after 6, 12, and 18 months (p < 0.001), there were no important differences with regard to tissue reaction. Concerning plaque adhesion, surface quality with regard to the lower side, interfaces between denture acrylic and metal and the boundary between denture acrylic and denture tooth PMMA was rated higher than VLCR. The surface quality of the upper side of the denture saddles showed no significant differences (p > 0.05). Neither VLCR nor PMMA showed discoloration at any point in time (p > 0.05). It can be concluded that VLCR is a viable alternative for the production of removable dentures. Especially in patients with hypersensitivities to PMMA, VLCR is particularly suitable for clinical use.     

T-bar clasp-retained removable partial denture as an alternative to implant-based prosthetic treatment

This article reports the case of a 55-year-old female patient who presented with unsatisfactory temporary crowns in the right mandibular premolars and molars, and a premolar-to-molar fixed partial denture in the left side. The clinical and radiographic examinations revealed a fracture of the left first premolar that was a retainer of the fixed partial denture and required extraction. Initially, the acrylic resin crowns were replaced by new ones, and a provisional RPD was made using acrylic resin and orthodontic wire clasps to resolve the problem arising from the loss of the fixed partial denture. Considering the patient's high esthetic demands, the treatment options for the definitive prosthetic treatment were discussed with her and rehabilitation with implant-supported dentures was proposed because the clinical conditions of the residual alveolar ridge were suitable for implant installation, and the patient's general health was excellent. However, the patient did not agree because she knew of a failed case of implant-retained denture in a diabetic individual and was concerned. The patient was fully informed that implant installation was the best indication for her case, but the arguments were not sufficient to change her decision. The treatment possibilities were presented and the patient opted for a clasp-retained removable partial denture (RPD) associated with the placement of crowns in the pillar teeth. The temporary RPD was replaced by the definitive RPD constructed subsequently. Although RPD was not the first choice, satisfactory esthetic and functional outcomes were achieved, overcoming the patient's expectations. This case report illustrates that the dentist must be prepared to deal with situations where, for reasons that cannot be managed, the patient does not accept the treatment considered as the most indicated for his/her case. Alternatives must be proposed and the functional and esthetic requirements must be fulfilled in the best possible manner.     

The reinforcement of dentures

The material most commonly used for the fabrication of complete dentures is poly (methyl methacrylate) (PMMA). This material is not ideal in every respect and it is the combination of virtues rather than one single desirable property that accounts for its popularity and usage. Despite its popularity in satisfying aesthetic demands it is still far from ideal in fulfilling the mechanical requirements of a prosthesis. The fracture of dentures may be due to the mechanical properties of the acrylic resin or may be due to a multiplicity of factors leading to failure of the denture base material. Generally, there are three routes which have been investigated to improve the impact properties of PMMA: the search for, or development of, an alternative material to PMMA; the chemical modification of PMMA such as by the addition of a rubber graft copolymer; and the reinforcement of PMMA with other materials such as carbon fibres, glass fibres and ultra-high modulus polyethylene. The following review of attempts to improve the mechanical properties of denture base material takes account of papers published during the last 30 years.     

Comparison between balanced occlusion and canine guidance in complete denture wearers--a clinical, randomized trial.

OBJECTIVE: Two occlusal concepts exist for the setup of complete dentures: canine guidance and balanced occlusion. These two schemes were studied in a randomized clinical trial of 22 patients. METHOD AND MATERIALS: Subjective data were collected using a visual analog scale that described the patients' satisfaction with the esthetic appearance, the ability to chew, the ability to speak, and denture retention. Objective data were collected on the number of denture ulcers, the number of occlusal contacts, and denture retention during eccentric movements. Statistic evaluation was performed with the Friedman test. RESULTS: Patients assessed canine-guided dentures to be significantly more satisfying in esthetic appearance, mandibular denture retention, and chewing ability. The ability to speak and the retention of maxillary dentures were not influenced by the occlusal concept in the patients' opinion, whereas the examiners found that maxillary canine-guided dentures lost retention more frequently during eccentric movements than balanced dentures. The objective inspection of mandibular denture retention underscores the patients' assessment, showing that the mandibular canine-guided dentures are much more stable during laterotrusive and protrusive movements. CONCLUSION: Canine guidance can be used successfully in complete denture treatment as it provides better mandibular denture retention, esthetic appearance, and chewing ability.     

Clinical application of removable partial dentures using thermoplastic resin—Part I: Definition and indication of non-metal clasp dentures

This position paper proposes a definition and naming standard for removable partial dentures (RPDs) using thermoplastic resin, and presents a guideline for clinical application. A panel of 14 experts having broad experience with clinical application of RPDs using thermoplastic resin was selected from members of the Japan Prosthodontic Society. At a meeting of the panel, “non-metal clasp denture” was referred as the generic name of RPDs with retentive elements (resin clasps) made of thermoplastic resin. The panel classified non-metal clasp dentures into two types: one with a flexible structure that lacks a metal framework and the other having a rigid structure that includes a metal framework. According to current prosthetic principles, flexible non-metal clasp dentures are not recommended as definitive dentures, except for limited cases such as patients with a metal allergy. Rigid non-metal clasp dentures are recommended in cases where patients will not accept metal clasps for esthetic reasons. Non-metal clasp dentures should follow the same design principles as conventional RPDs using metal clasps.     

磁性附着体固位的固定-可摘式部分义齿

目的:应用磁性附着体解决固定)可摘式部分义齿的固位稳定问题。方法:将Magfit EX磁性附着体用作基牙冠外固位体,应用导面板、栓体栓道作为义齿的稳定装置,制作固定)可摘式部分义齿,并观察其应用效果。结果:15例患者的远中游离端缺损牙列被成功修复。经12~42月的随访观察,磁性附着体固位的固定)可摘式部分义齿具有良好的固位和稳定,义齿咀嚼效果良好,外形美观,体积小巧,使用舒适。结论:磁性附着体能满意地解决固定)可摘式部分义齿的固位稳定问题,显著提高义齿的修复质量。     

The effect of chopped poly(methyl methacrylate) fibers on some properties of acrylic resin denture base material

PURPOSE: The fracture of acrylic resin dentures remains an unresolved problem. Over the years, various approaches to strengthening acrylic resin have been suggested, including modifying or reinforcing the resin. The aim of this study was to investigate the effect of chopped poly(methyl methacrylate) (PMMA) fibers on some properties of acrylic resin denture base material. MATERIALS AND METHODS: PMMA in the form of fibers 0.75 mm in diameter and 5 mm in length was added to acrylic resin denture base material in various percentages to form a composite material. The influence on doughing and manipulation times and transverse strength was examined. The results were subjected to statistical analysis using a one-way analysis of variance and, where appropriate, the Scheffé test. RESULTS: The results showed that the doughing time was decreased by the addition of fibers, with the manipulation and setting times showing inconsistent changes. There was a significant difference between the materials in terms of the transverse strength. When the amount of PMMA fibers in the acrylic resin was increased, there was a decrease in the modulus of rupture and a decrease in the modulus of elasticity. The differences were shown to be statistically significant in some groups. CONCLUSION: The doughing time was decreased by the addition of fibers, while the manipulation and setting times showed inconsistent changes. The incorporation of chopped, randomly oriented PMMA fibers into acrylic resin had no advantage over the unmodified polymer in terms of strength and cannot be recommended as a reinforcing agent for acrylic resin denture base material.     

Comparison of the Dimensional Accuracy of Injection-Molded Denture Base Materials to that of Conventional Pressure-Pack Acrylic Resin

Purpose : This study compared the linear dimensional changes of 3 injection-molded denture base materials to that of conventionally processed polymethylmethacrylate (PMMA) resin.
Materials and Methods : An impression of an aluminum maxillary edentulous arch was made with a condensation silicone impression material (Denture Elasticon) to fabricate a gypsum master cast that was replicated as a silicone mold. A maxillary complete denture with acrylic teeth was waxed to full contour on the master cast and replicated to make 40 wax dentures. ERA attachments cast in metal (Rexillium) with indices milled into the centers were waxed into 3 positions in each denture for recording dimensional measurements of the wax denture. Ten dentures were allocated to each of 4 groups; Group 1 was processed using conventionally processed PMMA (Microlon), Group 2 used injection-molded PMMA (SR-lvocap), Group 3 employed injection-molded nylon (Valplast), and Group 4 used injection-molded styrene (Northern). All processed specimens were stored at room temperature (25°C, ambient humidity) for 1 week (while still on the master cast) before anteroposterior and cross-arch measurements were made using the ERA reference points with a digital caliper. After separation from the master cast and following water storage at 37°C for 7 days additional measurements were made.
Results : An analysis of the results showed that the effect of processing was not the same for the 3 dimensions studied, regardless of which dimension was considered ( p < 0.0001). The pattern of dimensional changes associated with the material type was not the same between the wax and processing stages as it was for the change between the processing and decasting stages ( p < 0.0001).
Conclusions : Processing the denture base materials produced unequal deformation in different dimensions (anterior-posterior and cross-arch). Each material tested also responded differently to the processing stages.     

Wear mechanisms of resin and porcelain denture teeth

The aim of this investigation was to describe the wear mechanism in occlusal contact areas of porcelain and acrylic resin denture teeth opposing different dental materials. A 55-year-old man with earlier extensive wear was given two complete dentures, as identical as possible, in the upper jaw. One of the dentures had diatoric teeth in cross-linked resin and the other denture had diatoric teeth in porcelain. The dentures were antagonizing a new gold-acrylic fixed bridge from 46 to 36. Two contralateral segments of the bridge were made as removable double crowns. The removable segments were made in different materials: gold, porcelain, light-cured resin, and heat-cured resin. Wear of the denture teeth was studied by scanning electron microscopy on replica models made after 1 and 2 months of antagonizing contact with the various materials. Wear of both porcelain and modern cross-linked resin teeth was mainly a fatigue type of wear. Abrasion was observed when hard particles were assumed to be part of the wear debris.