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口腔印模的质量直接影响修复体的准确性和修复质量。临床常用的口腔弹性印模材料有藻酸盐水胶体印模材料、琼脂水胶体印模材料、硅橡胶印模材料、聚醚橡胶印模材料和聚硫橡胶印模材料。各种材料组成不同,性能各异,临床使用时应根据具体病例,选择合适的印模材料和消毒方法,以获取最佳效果。本文主要介绍了各弹性印模材料性能特点及临床使用注意事项。     

局部数字化印模应用于单颗磨牙种植修复中的临床研究

目的:比较使用局部口内扫描数字化印模技术与传统硅橡胶制取印模技术在单颗后牙种植修复中的临床效果。方法:选择2021年6月～12月需行第一磨牙种植修复的患者86名,按照取模方式随机分为2组。分别使用局部口内扫描数字化印模技术(A组)和传统硅橡胶制取印模技术(B组)制取种植印模,由此制作氧化锆全瓷修复体。记录修复体调磨时间,按照改良的美国公共卫生署(United states public health service, USPHS)修复体标准对修复体进行评价,并使用Geomagic软件对修复体调磨量进行量化,视觉模拟量表(visual analogue scale, VAS)评估患者满意度。结果:2组印模的临床调磨时间有显著统计学差异;A组修复体边缘密合显著优于B组(P<0.05)。A组咬合面调磨量与B组有显著差异(P<0.05)。患者对数字化印模(A组)的偏好度更高,2组修复体满意度VAS评分则无统计学差异。结论:在种植后牙单冠制作中,相较于传统印模,采用局部口内扫描数字化印模技术不仅节省了临床操作时间,制作的修复体精度更高,同时患者满意度也更高,能达到与传统硅橡胶印模相似...     

改进的海带弹性印模材临床应用体会

口腔矫形工作中,印模材必不可少。1981年以来笔者应用改进的海带弹性印模材替代成品弹性印模材。经10余年临床实践和改进,制做义齿万件,效果良好。现将做法和体会介绍如下。     

两种不同印模技术对种植冠桥修复体边缘密合度的影响

目的 探讨两种不同印模技术对种植冠桥修复体边缘密合度的影响.方法 选取已植入2～3枚种植体并需行固定桥联冠修复的患者122例,对照组采用数字化印模,观察组采用合金夹板印模.比较两组修复体情况、修复体边缘密合度、被修复牙牙龈指数、患者满意程度.结果 观察组修复体过长或过短、早接触发生率显著低于对照组,有悬突、过松或过紧发...     

一步一步做好美学区种植修复软组织印模

口腔美学区种植修复中精确的软组织印模是获得良好粉白美学效果的重要基础。笔者将口腔美学区种植修复的软组织印模技术归纳为5种：口内个性化转移杆法印模、口外个性化转移杆法印模、临时修复体直接转移法印模、临时修复体间接转移法印模和数字化印模,本文逐一阐述做好种植修复软组织印模的方法和要点。     

口腔印模精确性的影响因素

口腔印模是否能真实反映口腔组织情况与制作修复体的精确度紧密相关.笔者就影响口腔印模精确性的因素,包括印模技术、托盘、印模材料、印模操作、印模消毒等进行综述.     

CS3600■口扫数字化印模技术与传统硅橡胶印模技术在磨牙全瓷冠修复中的比较

目的:比较数字化口内直接印模技术与传统精细硅橡胶印模技术在磨牙全瓷冠修复中的效果。方法:研究选取2019年10月~2020年1月于华中科技大学同济医学院附属同济医院口腔修复科行磨牙全瓷单冠修复治疗的患者32例,共计36颗患牙。实验组18颗患牙采用CS3600^■口内扫描仪制取数字化印模,对照组18颗患牙采用传统硅橡胶印模技术制取印模。记录两组取模时间、戴牙时间及患者舒适度,修复完成2个月参照改良美国公共卫生署(USPHS)标准对修复体进行评价。结果:实验组取模时间更短、取模更舒适;制作的修复体戴牙时间更短、修复体边缘适合性更好(P<0.05)。结论:在磨牙全瓷冠的修复治疗中,CS3600^■口内扫描技术在取模时间、取模舒适度、戴牙时间和修复体边缘适合性等方面都优于传统硅橡胶印模技术。     

松风SWIFT-TEMP临时冠桥材料在固定修复中的应用

笔者自 2 0 0 2 .2 .应用松风SWIFT -TEMP临时冠桥材料 ,在口内制作临时性修复体用于固定修复中 ,临床使用简便 ,效果良好 ,报导如下。材料和方法1.材料　松风SWIFT -TEMP临时冠桥材料 (快速自凝双丙烯树脂 ) ,松风DentureLiner硬化剂 ,藻酸盐印模材。2 .方法2 .1　印模准备　在牙体预备或拔牙之前 ,用藻酸盐取印模 ,固化后将印模的牙间隙区用雕刻刀挖除。可提高临时修复体的强度。在磨牙的缺牙区 ,可在基牙之间的印模上刻一槽沟。使临时修复体产生象桥一样的连接。然后将藻酸盐印模保持在潮湿的环境下备用。2 .2　基牙预备　按设…     

一步一步做好美学修复印模

精确的印模是保证修复体质量和美学修复成功的关键。制取口腔美学修复印模时常用的技术有:排龈技术,包括单线法和双线法;实体印模技术,包括单一印模法、双重一步印模法和双重两步印模法;数字印模技术,包括口内扫描和口外扫描,本文对此进行逐一介绍。     

改良树脂夹板在种植体开窗式印模技术中的应用研究

目的:介绍一种改良的种植体开窗式印模转移杆的树脂夹板,并评估其临床应用效果。方法:选择牙列缺损患者18例共44枚种植体,制取印模前于体外制作改良的个性化丙烯酸树脂夹板,返回口内连接固定开窗式印模转移杆,制取印模并制作18件修复体。安装修复体时检测边缘适合性,修复完成后第1、3、6和12个月复诊,以后每12个月复诊一次。复诊时检测种植体周围边缘骨吸收量、软组织健康状况及各种机械并发症。结果:18件修复体边缘适合性均良好,随诊时间12-36个月,平均22个月,第一年平均骨吸收量为0.82mm,随诊期内所有种植体周围软组织健康状况良好,未发现机械并发症。结论:本研究中改良树脂夹板应用于种植体开窗式印模技术精确性高,修复体临床效果良好。     

Bactericidal effect of a disinfectant dental stone on irreversible hydrocolloid impressions and stone casts

Infection control in dentistry focuses on the prevention of cross-contamination among patients, dentists, and dental auxilary personnel. This study evaluated the bactericidal effect of a dental gypsum material containing 0.25% chloramine-T on oral irreversible hydrocolloid impressions and dental casts. Eighty irreversible hydrocolloid impressions from 40 human volunteers were prepared. Forty impressions were poured with the disinfectant dental stone and a similar number were poured with a comparable, nondisinfectant stone. After setting for 60 minutes, the impressions and separated casts were sampled for bacterial contamination. The disinfectant stone inhibited bacterial growth in 39 of 40 impressions and casts, whereas all casts and impressions poured with the nondisinfectant stone were contaminated. The disinfectant dental stone containing chloramine-T was effective in eliminating bacterial contamination of both the irreversible hydrocolloid impression and stone cast.     

Assessing the quality of clinical procedures and technical standards of dental laboratories in fixed partial denture therapy

PURPOSE: This study was conducted to assess the quality of impressions and tooth preparations sent to dental laboratories in Jordan and to determine the technical capabilities of these laboratories to construct fixed partial dentures. MATERIALS AND METHODS: A sample of 136 impressions and stone casts were examined for clinical errors in 35 laboratories that construct fixed partial dentures. They were sorted into unusable, unsatisfactory, acceptable, or satisfactory categories. The type of impression material and tray, opposing arch impressions, and occlusal records were noted. Instructions to technicians were assessed for completeness and clarity. Information regarding laboratory staff and equipment were collected. RESULTS: Half of the specimens inspected were categorized as unusable or unsatisfactory; these were found in commercial laboratories. They showed at least one clinical error such as drags or indefinite finishing lines in impressions and inadequate reduction, undercuts, or obvious taper on stone casts. Alginate impression material was used for 65% of the cases. Only 27% of specimens were accompanied with instructions; of these 22% were graded poor. No occlusal records were available with 54% of the specimens and no articulators were used except in dental school laboratories. The dental schools and some commercial laboratories had the best staff and equipment and were more capable of fabricating fixed partial dentures than those of the Ministry of Health and the Royal Med cal Services. CONCLUSION: The quality of abutment preparation and impressions were unsatisfactory or unusable in 50% of cases. Of the 37 available instructions 8 were not clear. The dental schools and some commercial laboratories were technically capable of producing good quality fixed partial dentures.     

Some effects of disinfecting solutions on the properties of alginate impression material and dental stone

The study investigated the effect of two disinfecting solutions on one brand of alginate impression material and dental stone. Control impressions were immersed in water for equivalent periods and the effect of storage of impressions after disinfection or control immersion in water was also investigated. There were no significant dimensional changes in impressions poured after one hour. All impressions stored for 16 hours before pouring showed significant dimensional changes. Mixing dental stone with one disinfectant caused a significant softening of the cast. It is strongly recommended that all impressions are thoroughly rinsed with water after disinfection to prevent incorporation of disinfectant in the cast.     

A Survey of U.S. Prosthodontists and Dental Schools on the Current Materials and Methods for Final Impressions for Complete Denture Prosthodontics

PURPOSE: The purpose of this study was to survey members of The American College of Prosthodontists (ACP) to evaluate current materials and methods for final impressions for complete denture prosthodontics in the United States. In addition, those methods were compared with methods and materials taught in U.S. dental schools via a second survey sent to the chairpersons of prosthodontic/restorative departments. MATERIALS AND METHODS: An anonymous questionnaire was mailed to all 1762 active ACP members in the United States in 2003. A slightly modified questionnaire was also distributed to chairpersons of prosthodontic/restorative departments in the 54 U.S. dental schools. Data analysis was performed via frequency distribution and chi-square statistics. RESULTS: Nine hundred and forty-five questionnaires were returned by members of the ACP (54% return rate) and 42 questionnaires were returned by the U.S. dental schools (78% return rate). The majority of the reporting prosthodontists (88%) and dental schools (98%) use a border-molded custom tray for final impressions for complete denture prosthodontics. The most popular material for border molding was plastic modeling compound (67% of reporting ACP members, and 95% of the responding dental schools). Variability of the materials used for final impressions was observed, with the most popular materials being polyvinylsiloxane for the ACP members (36%) and polysulfide for the dental schools (64%). Statistically significant differences were found in the materials used for border molding by prosthodontists based on the time elapsed since completion of prosthodontic training. No differences were found in the materials used for impression of edentulous arches based on years of experience. Geographic location did not influence the materials and methods used by prosthodontists for complete denture final impressions. CONCLUSIONS: There was variability of the materials and techniques used for final impressions by ACP members and dental schools; however, overall there was an agreement on the materials and techniques used by prosthodontists and dental schools. Distinct trends for increasing use of polyvinylsiloxane and polyether for border molding procedures and impressions of edentulous arches were observed both in members of the ACP and in the U.S. dental schools.     

几种有效消毒方法对藻酸盐印模精度的影响

目的：比较几种有效的消毒方法对藻酸盐印模精度的影响，以寻求适合临床的消毒方法。方法：制作一个标准下颌牙列金属母模。采用3种有效的消毒方法（1500mg／L的NaClO消毒液浸泡消毒，1500mg／L的NaClO消毒液喷涂消毒及2％戊二醛消毒液浸泡消毒），分别按起效作用时间、起效作用时间延长10min和延长20min共分为9个实验组，每组均制备10个藻酸盐印模进行消毒处理后灌制模型，另外制取10个未消毒的藻酸盐印模作为对照组，用测量显微镜测量模型各标志点的距离，所得数据进行统计分析。结果：①1500mg／L的NaClO消毒液浸泡消毒10～30min对印模精度无明显影响。②1500mg／L的NaClO消毒液喷涂消毒藻酸盐印模45min时，出现统计意义显著的形变（P〈0．05）。③2％戊二醛消毒液浸泡处理50min、60min时，印模出现统计学意义显著的形变（P〈0．05）。结论：不影响藻酸盐印模精度的消毒方法为：1500mg／L的NaClO消毒液浸泡消毒10～30min，1500mg／L的NaClO消毒液喷涂消毒25～35min，2％戊二醛消毒液浸泡处理40min。     

Factors affecting the stability of sodium hypochlorite solutions used to disinfect dental impressions

Increased concern over the transmission of acquired immunodeficiency syndrome, hepatitis B, herpes, and other diseases has prompted research into the disinfection of dental impressions. Among the factors to be considered when dental impressions are disinfected is the stability of the disinfectant solutions during storage and use. This study is concerned with the effect on disinfectant solutions of repeated immersion of alginate dental impressions taken in metal trays. The effects of the impression materials, metal trays, and dilution were evaluated, and the impact of light, heat, and storage were also addressed. The findings indicated that in the test solutions, although considerable chlorine was consumed during the disinfection procedures, bactericidal activity was maintained, while in the control solution both chlorine content and bactericidal activity were remarkably stable.     

Direct mechanical data acquisition of dental impressions for the manufacturing of CAD/CAM restorations

OBJECTIVES: The basic prerequisite for the production of dental restorations by means of CAD/CAM technologies is the data acquisition (digitization). Currently, two methods are available, i.e. the extraoral digitization of master casts and the direct intraoral data acquisition. However, it seems to be beneficial to immediately digitize impressions directly at the dental office in order to combine the high precision of mechanical digitizing methods and to shorten the production process. The aim of this study was to investigate the measurement uncertainty (+/-2sigma) and the three-dimensional accuracy of the immediate tactile in-office digitization of dental impressions and of the mechanical digitizing of ceramic master dies using a high-precision touch-probe digitizer. METHODS: The experimental set-up consisted of ceramic master dies representing tooth 13 and 36 as well as their identical virtual models (CAD models). Fifteen one-step putty-wash impressions were taken from each tooth. The impressions as well as the ceramic master dies were digitized applying a standardized procedure. The datasets were aligned to the corresponding CAD models; then, a computer-aided three-dimensional analysis was performed. RESULTS: The digitizing of the dental impressions showed a measurement uncertainty of 5.8, mean positive deviations between 27 and 28microm, and mean negative deviations between -21 and -31microm. The digitizing of the ceramic master dies showed a measurement uncertainty of 2.8, mean positive deviations between 7.7 and 9.1microm, and mean negative deviations between -8.5 and -8.8microm. CONCLUSION: Mechanical digitizers show a very low measurement uncertainty and a high precision. The immediate tactile in-office digitization of impressions cannot be recommended as adequate data acquisition method for CAD/CAM restorations. It is recommendable to digitize clinical sites extraorally, i.e. after taking an impression and fabricating a model cast thereof.     

Disinfection and communication practices: a survey of U.S. dental laboratories

BACKGROUND: The need to disinfect impressions is crucial to prevent the transmission of infectious diseases. The authors report the results of a survey of U.S. dental laboratory directors. The survey was designed to determine how well dental laboratory personnel are communicating with dentists regarding the disinfection of impressions, and, in turn, what laboratory technicians are doing to protect themselves against microbial cross-contamination. METHODS: Four hundred dental laboratory directors were selected in a blinded and random manner. To create a geographically representative sample, an equal number of laboratory directors from the East, Midwest and West were interviewed. A survey consisting of 16 open-ended questions was conducted by trained interviewers via 10- to 15-minute telephone interviews. All dental laboratory directors stated that they were thoroughly familiar with their laboratory's disinfection protocol. RESULTS: The survey documented that the majority of impressions were made of polyvinyl (57 percent) or polyether (27 percent) materials. Only 44 percent of the respondents stated that they knew if the impressions they received had been disinfected. Twenty-three percent of the laboratory directors did not know the method of disinfection used, and 47 percent did not know the length of time involved. Forty-five percent of the respondents reported that they receive inadequate instruction in regard to disinfection techniques. No one class of impression materials was found to be more problematic than others by the laboratory directors. CONCLUSIONS: The results indicate a significant and problematic lack of communication between these team members. The responses also suggested that laboratory-perceived problems with impressions were not linked to any particular type of material, but more to the disinfection technique used. PRACTICE IMPLICATIONS: Lack of communication between dentists, staff members and dental laboratory personnel, along with poor training of laboratory personnel in disinfection techniques, may have a direct effect on the prosthetic results achieved in dental practices.     

Survey of prosthodontic impression procedures for complete dentures in general dental practice in the United Kingdom

STATEMENT OF PROBLEM: Anecdotal evidence suggests impression techniques used in general dental practice may vary from those taught at dental schools. There is little published information on this topic. PURPOSE: This study identifies the materials and methods used by general dental practitioners for recording impressions for the provision of replacement of complete dentures. METHODS: A total of 905 questionnaires were sent to general dental practitioners in the Greater Manchester area to identify current clinical practices. RESULTS: The results revealed that 88% of respondents use only irreversible hydrocolloid for primary impressions. If multiple responses are included, 99% of respondents mentioned irreversible hydrocolloids as an option for primary impressions. In response to the same question for secondary impressions, 94% of respondents mentioned irreversible hydrocolloids as an option. Other material mentioned as an option for secondary impressions included zinc oxide-eugenol (29%) and polyvinyl siloxane (13%). With regard to special trays, 75% of respondents routinely used laboratory constructed special trays to take definitive impressions. Questions on the requisite spacing, perforation, handle design of special trays, and on disinfection showed a diversity of opinion among practitioners. CONCLUSIONS: Although this survey reflected a diverse range of clinical preferences, it is clear that irreversible hydrocolloid dominates the impression market for complete dentures. The use of special trays is normal practice for complete dentures in general dental practice in the United Kingdom.     

Antimicrobial effect of 4 disinfectants on alginate, polyether, and polyvinyl siloxane impression materials

PURPOSE: Dental impressions often carry microorganisms that may cause cross infection from patients to dental staff. The aim of the current study was to determine the effectiveness of 4 different disinfectant solutions on 3 commonly used impression materials--alginate, polyether, and polyvinyl siloxane--to establish a protocol for disinfection of these impression materials after clinical exposure and prior to handling in the dental laboratory. MATERIALS AND METHODS: A total of 45 impressions were taken from the maxillary dentate arches of 15 dental staff participants at the Department of Dentistry, Prince Rashid Hospital, Irbid, Jordan. For each participant, 3 successive impressions were recorded in the different impression materials. For each impression, 6 specimens were dissected from 6 different locations and exposed to 6 different regimens: 1 was left untreated, 1 was immersed in sterile water for 10 minutes to serve as a control, and the remaining 4 specimens were exposed to 4 different disinfection treatments (Dimenol, Perform-ID, MD 520, and Haz-tabs). Serial dilutions of the suspension were carried out and counted by the Miles-Misra technique (inoculation on Columbia blood agar for quantification). The dilutions were aerobically incubated at 37 degrees C for 48 hours. RESULTS: The disinfectants were able to completely eliminate microorganisms carried by the impressions. For those undisinfected specimens, the results showed that untreated alginate impressions appear to carry more microorganisms (P < .05) than the other 2 rubber impression materials used in the study. For those specimens immersed in sterile water for 10 minutes (control group), the number of microorganisms eliminated was increased from 62% to 90% compared to those left untreated. CONCLUSION: Impression materials may act as a vehicle for the transfer of microorganisms from the patient's mouth to dental personnel. Impressions should be disinfected to eliminate the risk of cross contamination.