自制口内平行备牙仪对提高牙体预备质量的研究

目的：研制口内平行备牙仪,用提高牙体预备质量。方法：根据Parallel-A-Prep的原理,制成由金属托盘、可折叠的延伸臂、适配器、观测针组成的新型口内平行备牙仪。在模型上对64颗后牙进行备制,测量倒凹数、倒凹坡度及轴面会聚度并与传统的目测法进行比较。结果：用新型口内平行备牙仪备牙后,倒凹数和内聚度远远小于目测法备牙法,大大提高了固定桥基牙的共同就位道。结论：口内平行备牙仪可提高固定桥基牙的共同就位道,大大减少倒凹的发生及内聚角的度数,明显提高牙体预备质量。     

口腔内就位道观测仪指导口腔医学生固定义齿牙备的实验研究

目的 研究口腔内就位道观测仪在口腔医学生固定义齿就位道确定中的作用。方法 选取80名经过系统牙体制备理论教育的医学生,随机分为四组(A1组：采用就位道观测仪指导制备前牙;A2组：采用常规目测法制备前牙;B1组：采用就位道观测仪指导制备后牙;B2组：采用常规目测法制备后牙),每组各20名,分别在仿真头颅模型系统上模拟21、36缺失进行固定桥基牙制备。制备后用3D扫描仪行口内模型扫描,将获取数据导入CAD软件进行倒凹及会聚度的分析和测量。凡预备体无倒凹者为合格,存在倒凹者为不合格。采用统计学软件进行合格率及基牙平均会聚度的分析。结果 A1组合格16人(合格率为80%);A2组合格9人(合格率为45%);B1组合格15人(合格率为75%);B2组合格5人(合格率40%)。数据分析表明,A1组优于A2组,两者存在差异性(P<0.05),B1组优于B2组,两者存在高度差异性(P<0.01)。桥基牙会聚度A1组优于A2组,B1组优于B2组,均存在高度差异性(P<0.001)。结论 使用口内就位道观测仪可以提高医学生固定义齿共同就位道的成功率。     

一步一步做好微创修复的贴面牙体预备

随着现代口腔微创修复理念的发展,牙体预备量少、保存牙釉质多、以粘接固位为主的微创修复体在临床应用得日益广泛。前牙贴面和后牙 贴面是常见的微创修复体类型。精确的牙体预备是微创修复治疗成功的重要基础。本文以前牙对接型贴面和后牙经典型 贴面修复为例,详细介绍其牙体预备量、车针选择、操作步骤的具体要求。...     

1312件单冠预备体数字化模型的关键预备质量指标的分析研究

目的 探讨单冠预备体数字化模型的质量现状,为医技间科学交流、提高修复体质量、降低返工率提供基础数据.方法 随机抽取某一大型义齿工厂的1312件单冠数字化模型(前牙180件,前磨牙294件,磨牙838件),数字化模型由3名工龄一致的调查员使用同一椅旁口内扫描系统(CEREC)扫描获得的.采用CEREC SW 4.4软件对...     

牙槽嵴带有组织倒凹的全口义齿修复

作者在工作模上采用选择性填充牙槽嵴区组织不利倒凹 ,合理利用部分组织倒凹 ,达到全口修复的良好临床效果。材料与方法 :全口无牙颌患者 30例 ,其中男性 18例 ,女性 12例 ,年龄在 48至 6 8岁之间 ,其牙槽嵴均带有不同程度、不同部位的组织倒凹。制作过程中 ,通过采用选择性填充组织倒凹方法制作全口义齿 30付。材料均采用上海齿科材料厂生产的藻酸盐弹性印模材料取模 ,用口腔科普通白石膏灌注工作模。方法 :在工作模型上唇侧骨嵴倒凹区 ,先进行模型观测划界线 ,确定可利用倒凹组织和不可利用倒凹组织区 ,用石膏或人造石对上颌前弓区唇侧、…     

一种特殊的装盒填胶法

胶连的可摘局部义齿都要经过装盒、填胶的过程 ,装盒时先装下盒 ,后装上盒 ,装下盒时切忌形成倒凹 ,否则当装好上盒后两盒分不开或把模型损坏。有的牙列缺损模型 ,做好蜡型后 ,按一般装盒法无法消除倒凹 ,如 :上颌前、后牙均有缺失 ,余留的前牙唇向倾斜较大 ,缺失的前牙唇侧必须放基托 ,选的牙面与牙槽嵴间隙不太大 (无法由此间隙填胶 ) ,这种病例模型按普通装盒法必然在唇侧形成倒凹。若用石膏把唇面填满 ,又无法装胶。笔者经过反复实践 ,采用一种特殊的装盒填胶法 ,可克服以上困难。具体方法是 :　　作者单位 :0 5 0 0 17河北医科大学口腔…     

几种不同金属基底烤瓷修复体的临床比较

金属烤瓷冠已成为临床上常用的修复方法之一,随着齿科材料的发展,金属烤瓷冠的修复材料也在进一步完善。本研究将4种不同金属基底烤瓷冠的修复效果从临床角度进行比较,分析如下:1材料与方法1.1临床资料收集牙釉质发育不全、四环素牙、变色牙、牙体缺损患者105例,共185颗牙,分别制作镍铬合金基底烤瓷冠80件(前牙54件,后牙26件),钛合金烤瓷冠(含钛量4%～7%)50件(前牙35件,后牙15件),高金合金基底烤瓷冠(含金量86%)25件(前牙17件,后牙8件)及金沉积基底烤瓷冠(含金量99.9%)30件(前牙23件,后牙7件),共185件。1.2操作步骤采用Vita比色板比色;牙体…     

排龈线在固定修复中的临床应用

目的:探讨在制作固定义齿修复时使用排龈线对颈缘制作的精密度和适合性是否有明显提高。方法:在178例患者的前牙及双尖牙固定修复中使用排龈线,并观察其牙体颈缘预备及制取模型的效果。结果:临床效果满意,成功率98.7%。结论:固定修复中使用排龈线可以明显提高颈缘制备的精度和密合度,具有良好的临床效果。     

烤瓷修复前牙舌向错位

我科自1993年起应用烤瓷修复80例,120个前牙舌向错位牙,男25例,女55例,年龄17—45岁。上颌侧切牙11个,下颌侧切牙8个,其中龋牙21个,牙髓病,尖周病牙16个,余牙均健康,患牙髓病,尖周病均应作常规根管治疗术。有牙石或牙龈炎症应预先作洁治,不良修复体应拆除,残存粘固粉均应清除,待炎症消退后取模,在取模之前牙体预备的要求是:轴壁相互平行,冠的最大周经降至颈缘,各面无侧凹,舌面预备出1.2—1.5mm的间隙,去除舌隆突至龈缘的例凹,唇面预备出1.2—1.5mm间隙,因唇面前1/3咬(牙合)较紧,可多磨除些、然后作好邻面,切斜面、肩台的预备,取完模后,用比色板比色,烤瓷做好后进行粘固戴牙。 修复后观察3年,其120个牙烤瓷修复体完整良     

虚拟仿真系统在全冠牙体预备实验教学中的应用

目的:探讨Simodont虚拟仿真系统在全冠牙体预备实验教学中合理有效的应用方法.方法:选择后牙金属全冠牙体预备实验项目,对117名2014级口腔医学本科学生进行对照研究,对所有学生完成传统仿头模实验教学后,利用Simodont虚拟仿真系统中的后牙金属全冠牙体预备实验模块对实验组学生进行培训,考核前利用超硬石膏模型对对...     

Effects of crown movement on periodontal biotype: a digital analysis

Orthodontic treatment has important correlations with periodontal changes. Various mechanical and biological factors are involved in determining such changes, but anatomical and morphological variables, generally addressed as periodontal biotype, play a key role. In measurement of such modifications, digital and non-contact reverse engineering technologies may be of tremendous advantage. The aim of this study is to retrospectively evaluate, in a series of digitized dental casts, some of the parameters addressing periodontal biotype and correlate them to extent and direction of tooth movement. Pre- (T0) and post-treatment (T1) dental casts of 22 patients were scanned by 3Shape TRIOS 3® scanner. A number of variables (crown ratio, gingival margin position, gingival contour, papillae position, gingival scallop) were investigated and their variations calculated after digital measurements on single casts at T0 and T1, or after direct measurement (T1 vs T0) on the superimposition and alignment of digital models. Univariate and multivariate statistics were then performed. No significant correlation was detected between the sagittal or vertical movement of dental crown and displacement of the gingival margin. On the other hand, vestibular gingival contour resulted significantly altered by vestibular and extrusion movements. Further studies are needed to ascertain the differential effect of bone and soft tissue on such modifications. The relationship between orthodontic treatment and the periodontium overcomes the consideration of gingival recession and includes all the concepts of periodontal biotype with its characteristics. Digital technologies and non-contact reverse engineering techniques now available have the potential to allow a more precise definition of such a relationship.     

Three-dimensional shape measurement of teeth. (6) Measurement of tooth model by tilting method by means of the double sensor laser displacement meter, and the simulation of occlusion

To measure the three-dimensional shape of the undercut portion of a molar model tooth, the tilting method was used. The measuring system was composed of a laser displacement meter with double sensor and a computer controlled tooth model scanning machine (CAMM-3). A model tooth was tilted on the gonio stage with +/- 20 degrees and measured divisionally, and a couple of data were connected by the TILCOMPO program. The undercut portions from the survey line to the tooth neck were measured and drawn by CG. By this tilting method, the whole shape of tooth including the undercut portion could be measured, and these data will be available for the production of the data base for CAD of prosthesis. The marginal line on the crown abutment measured previously was searched. Initially, the difference in the inclination dz/dx between the data before and behind was calculated, and the gingival line was extracted by limiting its value. Then, also by limiting the difference value, the margin located above the gingival line was determined. Thus the marginal line in contact with the inner and outer crown and a significantly important point for the production of crown by the CAD/CAM technique could be determined around the crown abutment. Another elementary attempt to simulate the occlusion by using the data of teeth models measured on the articulator was carried out. The maxillary and mandibular teeth were set on the articulator and the maxillary teeth turned over. The shapes of the 5-7 upper and lower molar were measured. The two data were connected and occluded by the "OCCLUS" program.(ABSTRACT TRUNCATED AT 250 WORDS)     

The association of simple anterior dental crossbite to gingival margin discrepancy

The purpose of this study was to determine the severity of gingival margin discrepancy affecting the mandibular incisors in children with a single-tooth anterior crossbite. The response of the position of the gingival margin to correction of the crossbite also was investigated. Twenty-two subjects with a single central crossbite and 16 subjects with a single lateral crossbite were identified from two orthodontic practices. Seventeen of the 22 central incisor patients had immediate posttreatment records available; six patients had long-term follow-up records. An insufficient number of posttreatment records were available for the patients with lateral crossbites. The mean clinical crown length of crossbite mandibular incisors, measured on the study models, was compared with mean crown length of contralateral control incisors and the difference in clinical crown length was determined. A gingival margin discrepancy was identified when the gingival margin of the crossbite incisor was at least 1.0 mm apical to the gingival margin of the control incisor. The proportion of subjects with gingival margin discrepancy was significantly higher in subjects with central incisor crossbite (12/22 = 54%) than in those with lateral incisor crossbite (4/16 = 25%), P less than 0.05. While a gingival margin discrepancy persisted for eight of the 17 central incisor crossbites after discontinuing the appliance, 8.9 +/- 4.7 months, the severity of the discrepancy showed a significant reduction from 2.2 +/- 0.5 mm to 1.3 +/- 0.8 mm, P less than 0.05. True recession with exposure of cementum was not observed in any subjects.(ABSTRACT TRUNCATED AT 250 WORDS)     

贵金属烤瓷冠桥的临床研究

目的 对贵金属烤瓷冠桥进行临床研究,评价其临床效果。方法 对65例贵金属烤瓷冠桥修复患者,其中冠185个,桥10件进行为期三年的随访研究。结果 烤瓷冠表面和颜色优秀率89.97％,解剖形态优秀率92.14％,边缘完整性优秀率91.31％,牙龈状况优秀率93.75％,相应地,固定桥则分别为:65.24％、68. 57％、68.20％、81.32％。总计失败率2.56％,无1例龈缘金属染色。结论 与非贵金属烤瓷冠相比,强度相当,外形及颜色更佳,无龈缘金属染色。     

根向复位瓣在附着龈宽度不足患牙的牙冠延长术中的应用

目的：：评价根向复位瓣在附着龈宽度不足的患牙牙冠延长术中的应用效果。方法：纳入需行牙冠延长术但附着龈宽度不足的患牙17颗,术中采用根向复位瓣法对牙龈瓣进行复位,记录手术前和术后6个月龈缘到牙体断端的距离、附着龈的宽度等指标并进行比较和评价。结果：术前17颗患牙牙体缺损边缘均位于龈下,术后6个月16例(94.11%)缺损边缘均暴露在龈缘冠方,龈缘根向位移距离(3.88±0.49) mm;17颗患牙附着龈宽度术前为(2.35±0.61) mm,术后6个月为(2.65±0.49) mm(P>0.05)。结论：牙冠延长术可以有效暴露牙体缺损边缘,为牙体缺损创造修复条件,避免切除过多角化龈导致附着龈宽度变窄。     

热压铸陶瓷二代（IPS—EMPRESSⅡ）与肩台瓷修复体颈缘效果三年临床评估

目的评估比较热压铸瓷二代（IPS—Empress）修复体和肩台瓷（IPS—Margin）金瓷修复体颈缘的临床效果。方法临床为63例患者的90颗患牙进行IPS—Empress热压铸陶瓷全冠修复,为98例患者的129颗患牙进行有肩台瓷的PFM全冠修复。永久性粘结后6个月和36个月复诊,比较修复体颈缘临床效果。结果在比较后发现铸瓷全冠和肩台瓷在牙龈变色,颈缘适合度,牙龈炎症三方面均无显著性差异。结论肩台瓷修复体与全瓷修复体能达到相同的颈缘效果。对想解决颈缘问题又无力支付全瓷冠的修复患者来说,肩台瓷不失为一种好的选择。     

Cross-sectional study of patients fitted with fixed partial dentures with special reference to the caries situation

The caries situation among 30 patients with fixed partial dentures was examined 3 yr after cementation of the constructions. The fit of the crowns on the abutment teeth, the size of the interproximal areas and the relation between the crown margin and the gingival margin were registered. Risk factors for caries development, such as salivary factors, microbiologic factors, oral hygiene and diet were evaluated for each patient. During the 3-yr period 54 caries lesions occurred in 25 patients. Eleven lesions were found on abutment teeth. Two were located on the root surfaces unconnected with the crown margin (greater than 2mm from the gingival margin), three were recurrent lesions, where the crown margin was located above the gingival margin but closer than 2 mm and six were recurrent lesions where the crown margin was located under the gingival margin. No single caries risk factor seemed to be so closely correlated to the number of caries lesions developed that it could be used alone to select of patients at risk. When the sum of the assumed negative factors was used, more caries was found among the patients with three or more factors with negative values in the group as a whole. However, predicting the development of caries in an individual case with a high degree of probability seems to be complicated. Generally speaking there was no indication that caries disease development was caused by the presence of the fixed partial denture per se.     

影响上颌中切牙单个种植修复体龈乳头高度的因素分析

目的分析影响上颌中切牙单个种植修复体龈乳头高度的因素，探讨促进种植修复美学效果的相关因素。方法选择16例上颌中切牙单个种植修复患者（30个龈乳头），通过分析临床资料、口内照片、X线片和研究模型，得到龈乳头高度及相关因素数据，采用多重线性回归方法进行分析。结果16例患者中切牙种植修复体龈乳头高度为（4．01±1．85）mm，影响龈乳头高度的相关因素按作用由大到小的排列顺序为：种植修复体外冠接触点高度、邻近天然牙邻面牙槽嵴顶高度、邻近天然牙邻面牙槽嵴顶到外冠接触点的垂直距离、种植修复体外冠邻面凸度、种植体基台与邻牙牙根距离、冠根长度比例、种植修复体邻面牙槽嵴顶高度、种植修复体外冠唇面凸度、探诊深度。结论中切牙种植修复体龈乳头高度受多种因素影响。     

In vitro comparison of master cast accuracy for single-tooth implant replacement

STATEMENT OF PROBLEM: The inaccuracy in transferring the position of the hexagonal head of a single implant to the working cast can result in a final single tooth crown, which clinically may present occlusal and/or interproximal contacts that are different from those contacts on the master cast obtained by the technician. PURPOSE: This in vitro study evaluated the accuracy of the master casts obtained using square pick-up impression copings for single-tooth replacement. Copings used were (1) copings as sold by the manufacturer, and (2) copings modified by sandblasting and coating with impression adhesive their roughened surfaces before final impression procedures. MATERIAL AND METHODS: A polymeric resin model with a standard single implant was used to simulate a clinical situation. A group of 20 impressions were made using nonmodified impression copings; a second group of 20 impressions were fabricated with modified copings. Master casts fabricated for both groups were analyzed to detect rotational position change of the hexagon on the implant replicas in the master casts in reference to the resin model. RESULTS: The rotational position changes of the hexagon on implant replicas were significantly less variable in the master casts obtained with the modified impression copings than in the master casts achieved with the nonprepared copings. CONCLUSION: Improved precision of the impression was achieved when the adhesive-coated copings were used.