金属烤瓷全冠两种颈缘设计对龈下微生物影响的研究

目的探讨瓷颈缘与金瓷颈缘对金属烤瓷全冠龈下微生物影响有无差异。方法采用自身对照设计,双侧上颌中切牙分别采用两种颈缘设计的镍铬合金烤瓷全冠修复10例。检测修复前、修复后72h、1周、1个月和3个月全冠唇侧龈下可培养细菌总量及革兰阴性菌构成比的变化。结果两组全冠修复后72h龈下微生物总量减少,1周、1个月和3个月递增。革兰阴性菌构成比在72h、1周、1个月递增,3个月和1个月无显著差异。各时间点两组修复体龈下可培养细菌总量及革兰阴性菌构成比无显著差异。结论瓷颈缘与传统金瓷颈缘对龈下微生物的影响没有显著差异,两者都会导致龈下微生物总量及革兰阴性菌增加。     

锻制卡环及其临床应用体会

在可摘局部义齿修复中,铸造卡环已被采用,但在广大经济不发达地区,仍多采用弯制卡环。弯制卡环弹性好,对基牙损伤小,制作设备简单,操作简便,经济耐用;其缺点是由于卡环与基牙接触面积小,固位、稳定及相互对抗作用差。而锻制卡环可具有铸造卡环及弯制卡环的诸多优点。以可摘局部     

铸造与冷弯卡环基牙菌斑致龋菌分析

目的 初步探讨可摘局部义齿卡环对基牙健康的影响。方法 对铸造、冷弯卡环可摘局部义齿初截一周前后,基牙菌斑中的主要致龋菌进行分析比较。结果 铸造卡环组初戴一周后,基牙菌斑中粘性放线菌与变形链球菌的百分比分别上升了２．３％和３．８％;冷弯卡环组初戴一周后,上述细菌百分比分别上升了５．９％和３．３％,二者间差异有显著性;铸造卡环组粘性放线菌上升的百分比显著低于冷弯卡环组。结论 可摘局部义齿卡环会增加基牙     

下颌磁性附着体覆盖全口义齿基牙龈沟内细菌的研究

目的 :了解磁性附着体基牙龈下微生物组成与正常龈下微生物组成比的差异及卫生指导前后基牙龈下微生物数量及组成的改变。方法 :检测卫生指导前后磁性附着体患者基牙以及正常人群相对应牙位龈下检出可培养微生物总量及组成比的变化。结果 :下颌磁性附着体覆盖全口义齿基牙龈沟中 ,G-杆菌及牙周炎相关细菌 ,如放线菌和其它不产黑色素G-杆菌组成较正常牙周增多 ,组成比为 19.2 3 %± 7.5 9%和 11.61%± 9.89% ;在卫生指导前后 ,基牙牙周龈沟内细菌的总量有所下降 ,而细菌的组成比没有明显变化。结论 :戴用下颌磁性附着体覆盖全口义齿是牙周炎的易感人群 ,但正确的卫生指导对基牙牙周细菌的控制有一定的效果     

可摘局部义齿基托对承托区腭粘膜微生物的影响

目的:了解基托戴入前后承托区腭粘膜微生物的变化及不同材料基托引起上述变化的差异。方法:检测备牙前、戴牙1月和3月时金属基托和塑料基托对应承托区腭粘膜面可培养菌总量及检出微生物组成比的变化。结果:戴牙1月和3月时,塑料基托对应腭粘膜可培养菌总量及乳杆菌、白色念珠菌组成比与备牙前相比均明显增加 (P<0105)。戴牙1月时,金属基托对应腭粘膜可培养菌总量及乳杆菌、白色念珠菌组成比与备牙前无明显变化。戴牙3月时,乳杆菌、白色念珠菌组成比与备牙前相比显著增加(P<0105)。两种材料制作的基托对应腭粘膜面可培养菌总量变化值无显著差异,但塑料基托所致白色念珠菌组成比的增加明显高于金属基托(P<0105)。结论:可摘局部义齿的戴用在基托与承托区腭粘膜间形成新的滞留区,有利于乳杆菌及白色念珠菌的繁殖。与金属基托相比,塑料基托更易促进白色念珠菌的生长。     

用于可摘局部义齿的一种特殊卡环

双侧后牙缺失 ,牙槽骨严重萎缩的病例 ,按常规设计弯制卡环 ,其稳定性差 ,且易变形、折断 ;设计常规铸造卡环 ,唇颊黏膜常有不适感 ,且折断后修理较困难。为此 ,笔者在尖牙上设计了宽臂铸造卡环 (图 1) ,上缘与导线一致 ,下缘与龈缘平齐 ,内面不进入倒凹区。由于卡臂很宽 ,与基牙之间的摩擦力和制锁作用可获得很好的固位效果 ,而且稳定性好 ,不易变形 ,不易滞留食物残渣 ,光滑的平面使唇颊黏膜感觉舒适。当然 ,由于对基牙覆盖的面积较大 ,易继发龈炎和龋齿 ,应嘱患者加强口腔清洁。图 1　尖牙宽臂铸造卡环用于可摘局部义齿的一种特殊卡环@王…     

卡环设计对牙龈健康的影响

本文通过测定戴义齿后基牙上的菌斑堆积、龈沟温度和菌斑微生物的分布,比较龈向进入卡环和(牙合)向进入卡环对牙龈的影响。结果表明,龈向进入卡环具有潜在的危害。实验方法受试者:选择下颌双侧游离缺失的病人10名,平均年龄57岁,所有病人义齿的双侧基牙相同,而钴铬合金修复体在两侧基牙上的卡环不同,一侧是Ⅰ型龈向进入卡环,另一侧是通常使用的(牙合)向进入卡环。另一组相同的试验是在12名牙科学生中进行,他们的牙列完整。给每个学生制作金属支架,6个上颌,6个下颌。实验前1个月教给病人口腔卫生方法和刷牙方法,使其达到实验的基本要求水平。戴义齿的当天作为实验起点。病人戴义齿后教给病人戴义齿的正确方法,要求餐后清洁,只在白天戴用等。观察时间:病人组:①戴义齿的当天;②戴后7天;③戴后3周;④戴后2.5～3.5月;⑤戴后6月～1年。学生组:①戴后第1周每     

自锁托槽与传统托槽对牙周指数和牙龈卟啉单胞菌影响的对比研究

目的 对比正畸患者粘接自锁托槽与传统托槽后牙周指数和牙龈卟啉单胞菌的变化。方法 将正畸患者30例按托槽类型分为2组,每组15例。试验组粘接Clippy自锁托槽,对照组粘接O-PAK传统直丝弓托槽。分别在矫治器戴入前,戴入后第1、3个月检查牙周临床指标（包括菌斑指数、牙龈指数、探诊深度）,同时采集龈下菌斑样本,利用实时荧光定量聚合酶链反应检测样本中牙龈卟啉单胞菌和总细菌的数量,计算出牙龈卟啉单胞菌的构成比。结果 治疗前试验组与对照组牙周指数、牙龈卟啉单胞菌构成比差异无统计学意义（P＞0.05）。治疗中,2组牙周指数、牙龈卟啉单胞菌构成比均随时间延长而升高（P＜0.05）;试验组在粘接矫治器后第1、3个月,牙周指数、牙龈卟啉单胞菌构成比均低于对照组（P＜0.05）。结论 与传统托槽对比,自锁托槽更利于口腔卫生维护,但仍会对口腔卫生造成不利影响。     

应用实时荧光定量PCR定量检测慢性牙周炎患者龈下菌斑中牙龈卟啉单胞菌

目的 检测慢性牙周交患者和牙周健康人龈下菌斑中牙龈卟啉单胞菌、总菌量和牙龈卟啉单胞菌所占比例,探讨牙龈卟啉单胞菌与牙周炎发生发展的关系.方法 采集经常规PCR方法检测牙龈卟啉单胞菌为阳性的76例慢性牙周炎患者和25例牙周健康者的龈下菌斑,应用TaqMan实时荧光定量PCR方法定量检测样本中牙龈卟啉单胞菌、总菌量;构建含有牙龈卟啉单胞菌和真细菌扩增片断的重组质粒,建立定量标准.结果 本研究设计的引物和探针具有良好的特异性及敏感性.病变位点龈下菌斑中牙龈卟啉单胞菌数量和总菌量均比健康位点高(P<0.001),两组位点牙龈卟啉单胞菌在菌斑中的比例没有差异(P>0.05);细菌数量与探诊深度间存在显著正相关关系(P<0.001),不同的探诊深度牙龈卟啉单胞菌所占比例无统计学差异(P>0.05).结论 龈下菌斑中牙龈卟啉单胞菌的数量水平及细菌总量与牙周状况、牙周炎发展有密切关系,实时荧光定量PCR对牙周病学研究具有广泛的应用前景.     

CDIC柱状种植体周龈下菌群变化的2年观察

目的：了解种植体周龈下菌群构成变化与种植体周围组织炎的关系，方法：观察64枚CDIC种植体植入术后2年内种植体周龈下细菌构成变化以及相关临床指标。结果：种植体植入术后1月、3月、6月的龈下球菌比值降低。螺旋体，梭形菌比值增高，杆菌，弯曲菌比值差异无显著性意义。术后12月，24月这五类菌的比值接近术前水平，临床菌斑指数，龈沟出血指数高者，种植体周龈下细菌中球菌的比值较低，梭形菌，螺旋体的比值较高。结论：早期进行口腔卫生指导和定期细菌学检测，对提高种植义齿成功很有必要。     

A measurement of clasp forces on teeth

A method that measures the force which clasps transmit to abutment teeth was developed and a comparative study was made between the effectiveness of a wrought wire clasp and that of a cast bar clasp. A transducer, using a resistance strain gauge, measured the flexure of clasps and the forces exerted by the clasps on abutment teeth. The cast bar clasps were more flexible than the wrought wire clasps of equal length. All of the clasps tested exerted forces against the teeth when the removable partial denture bases were at rest. The wrought wire clasps flexed a greater distance and exerted more force against the abutment teeth when the casting was seated and removed from the model. The forces exerted by the clasps when the casting bases were moved were different from each other and yet followed a pattern. The force increased for both types of clasps as the bases were depressed; however, the wrought wire clasp exerted more force than the cast bar clasps.     

Comparison of cast Ti-Ni alloy clasp retention with conventional removable partial denture clasps

STATEMENT OF PROBLEM: The elastic property of Ti-Ni alloy may be a desirable property for cast removable partial dentures. However, little is known about the retentive properties of cast Ti-Ni alloy clasps. PURPOSE: This in vitro study investigated the retentive force of various types of clasps during repeated cycles of placement and removal to determine whether Ti-Ni alloy clasps maintain their initial retentive force under varied conditions, including different retentive undercut depths and clasp size (thickness and width). MATERIAL AND METHODS: The test models were developed using a mandibular dentiform with a horizontal plane of occlusion. Two complete metal abutment crowns were made for the left second molar, differing only in retentive undercut depths. A total of 98 clasps (n=7) were fabricated, including 14 wrought wire clasps and 28 clasps from each of the following alloys: Co-Cr alloy (Biosil), Type IV gold alloy (Cast-4), and Ti-Ni alloy (TN-10). Clasps were made to engage one of 2 retentive undercut depths (0.25 mm or 0.75 mm) and were made in 2 sizes (0.8 mm or 1.4 mm). Each clasp was radiographically examined for casting defects and porosity. The force (N) required to remove the clasps was measured using a universal testing machine with a crosshead speed of 10 mm/min. After measuring the retentive force, a masticatory simulator was used to cycle the clasps on and off the metal crown 500 times, simulating the insertion and removal of a removable partial denture clasp. The cycling sequence was repeated 10 times, and retention force was measured after each sequence. The internal surface of the clasp arms was examined for evidence of metal fatigue using scanning electron microscopy. Data were subjected to 2-way and 4-way analysis of variance, followed by Scheffe's multiple comparison test (alpha=.05). RESULTS: Co-Cr alloy and gold alloy clasps in the 0.25-mm retentive undercut groups experienced a gradual decrease in retentive force measurements (P<.001). In contrast, the Ti-Ni alloy clasps maintained a retentive force of approximately 1.8 N and 2.6 N for the 0.8 mm and 1.4 mm clasp groups, respectively. Although Ti-Ni alloy clasps' retentive force was reduced slightly after the first cycling sequence, it was negligible compared with other clasps tested. The wrought wire clasps also retained their retentive force until the final cycling sequence. A similar trend was found in the clasp groups engaging 0.75-mm retentive undercuts. CONCLUSION: Although the end-point retention for all the clasps was similar, there was less change in the retentive force of the cast Ti-Ni alloy clasps after repeated cycling sequences of simulated placement and removal.     

Flexibility of technopolymer clasps compared with cobalt-chromium and titanium clasps.

Patients often cite lack of retention and poor aesthetics as reasons for not wearing their partial dentures. Traditional metal alloy clasps have been shown to exert forces on abutment teeth that exceed those capable of producing tooth movement. In addition, metal display on anterior teeth is often unacceptable. The technopolymer materials are purported to have superior flexibility and exert less force than the metals. This study compared the flexibility and forces produced by technopolymer clasps with those exerted by cobalt-chromium and titanium clasps. The results showed that the technopolymer clasps were up to ten times as flexible as the metal clasps, and they returned to their pretest dimensions after being stretched. In addition, they exerted forces on the abutment teeth that fall within the range of those considered safe for use. This coupled with their pleasing aesthetics makes them suitable for use on periodontally compromised teeth, those with deep undercuts and on anterior teeth.     

The effect of removable partial dentures on periodontal health of abutment and non-abutment teeth

BACKGROUND: A removable partial denture (RPD) is a common treatment available for restoration of partially edentulous ridges. Longitudinal studies indicate that RPDs have been associated with increased gingivitis, periodontitis, and abutment mobility. METHODS: A total of 205 patients with RPDs participated in this study. There were 80 males and 125 females aged 38 to 89, with 123 maxillary and 138 mandibular RPDs. Patients were wearing existing RPDs for different periods ranging from 1 to 10 years. A two-part questionnaire was devised for this study. In the first part, patients answered questions on gender; age; smoking habits; denture age; denture wearing habits; mouth odor; and problems with food accumulating under the denture base, on the outside surface of the denture, and on the outside surface of remaining teeth after eating. The Kennedy classification, material, denture support, denture base shape, and number of teeth in contact, number of existing clasps, and occlusal rests were categorized. The quality of denture construction was also evaluated. In the second part of the questionnaire, baseline recordings of plaque (PI), gingival (GI), and calculus (CI) indexes were made, and Tarbet index (TI), as well as probing depth (PD), gingival recession (GR), and tooth mobility (TM) were measured, both on abutment and non-abutment teeth. RESULTS: Significant differences (P <0.01) were noted for PI, Cl, GI, PD, TM, and GR between abutment and non-abutment teeth, with abutment teeth showing more disease. CONCLUSIONS: RPD design plays an important role in the state of the periodontium. Appropriate design and good oral hygiene may decrease the appearance of periodontal disease.     

Removable partial dentures applied by electric welding and soldering methods

The joining procedure for uniting metal structures is very important in the dental clinic, and various kinds of metal joining methods have been performed for clinical application. The conventional torch soldering method using a blow torch has been generally adopted. However, it has several clinical problems, especially in the construction of removable partial dentures. The base metal wires made of a chromium-cobalt alloy are subject to changes in their mechanical properties caused by heating, when wrought wire clasps are joined to rests or frameworks. In addition to the flexibility of wrought wire clasps, damage to acrylic resin denture bases and acrylic resin teeth occurs in the repair of removable partial dentures. In this paper, the electric resistance welding and soldering methods were applied to attach wrought wire components to a removable partial denture framework to resolve the problems of the torch soldering method. As a result, it is suggested that these electric resistance welding and soldering methods have the following advantages, as compared with the conventional torch soldering method. 1. When using this electric resistance welding method, it is possible to fix metals temporarily to each other more securely and strongly than the conventional temporary fixation methods using sticky wax or acrylic resin. 2. The electric resistance soldering method does not require any heat insulation or a partition as the torch soldering method does, because the soldered area is only heated partially. 3. In the case of soldering electrically wrought wire clasps to metal structures such as rests and connectors, there is no fear of of overheating a wide area of wires.(ABSTRACT TRUNCATED AT 250 WORDS)     

The flexibility of titanium clasps compared with cobalt-chromium clasps.

Retention of a partial denture depends on the amount of undercut engaged on an abutment tooth and the flexibility of the clasp. Flexibility is influenced by clasp length and the denture base material. Titanium clasps are purported to have greater flexibility than cobalt-chromium cast clasps which should enable them to engage deeper undercuts or be used where shorter clasp arms are needed such as on premolar teeth. This study investigated the flexibility of cast titanium clasps with three commonly used cobalt-chromium clasps through comparative measurements of their tip deflections and yield strengths. The results showed that the titanium clasps were significantly (P < 0.05) more flexible than the cobalt-chromium clasps. However, all four materials were found to be flexible enough to engage an undercut of 0.25 mm without exceeding their yield strengths.     

Nd—YAG激光在可摘局部义齿基牙预备的应用

为了解决可摘局部义齿修复过程中牙本质过敏基牙预备的困难和戴牙后加重磨耗等问题，于１９９１年起，对２０例（３０颗）牙本质过敏基牙在预备前、后进行了Ｎｄ－ＹＡＧ激光治疗。经过０．５～４年的临床观察，结果表明该疗法可以明显减轻患者在基牙预备时的敏感与不适，使得基牙预备顺利完成且无副作用，治疗后支托窝与隙卡沟均无明显磨耗。根据本研究结果，建议将Ｎｄ－ＹＡＧ激光治疗作为对可摘局部义齿的牙本质过敏基牙预备的常规方法，对健康基牙亦可在预备后应用。     

老年人可摘局部义齿修复对基牙的影响

目的:分析研究老年人可摘局部义齿修复后对基牙的影响,探讨其原因及预防措施。方法:对95例牙列缺失后的老年人行冷弯卡环固位式可摘局部义齿修复,记录和比较戴可摘局部义齿后基牙和非基牙的龋坏率和缺失率,用χ2检验分析其结果有无差异,并对影响基牙的原因进行分析。结果:戴用可摘局部义齿5a后,基牙的患龋率(17.38%)显著高于非基牙(7.10%);因牙折、牙周病松动及龋坏无法保留而拔除的基牙缺失率(27.01%)也显著高于非基牙(7.79%)(P<0.01)。结论:冷弯卡环固位可摘局部义齿修复后在一定程度上可增加老年人基牙的患龋率和缺失率。