摘要:

SummaryThe aim of this paper is to describe anin vitromethod which provides clear and accurate details of root canal shape. The method utilizes the technique of contact microradiography to produce high resolution, two‐dimensional, real‐size images of canals in a longitudinal plane. Specimens can be accurately rotated through 90° allowing images to be produced in a bucco‐lingual and mesio‐distal direction. The method is simple, relatively rapid and can process large numbers of teeth without the need for complicated and expensive mounting blocks or film holders. The technique can be used to produce pre‐ and post‐operative images of canal shape which can be superimposed to delineate the dentine removed during canal preparation. The method is thus suitable for the evaluation of the shaping ability of endodontic instruments and preparatio

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1995.tb00160.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryThe cutting efficiency of different endodontic hand instruments and the effects of instrumentation on curved canal shape were investigated under standardized experimental conditions using an automatic testing device.Cutting efficiency in rotary motion was assessed by determination of the maximum penetration depth of the instruments into a cylindrical canal in a special resin block (size 25 and size 35 instruments). Changes in canal shape were determined by instrumentation of standardized canals (42° curvature) incrementally from size 15 to size 35.Except in the case of one instrument, size 35, in both sizes tested flexible instruments reached significantly (P<0.05) greater maximum penetration depths than conventional reamers or K‐files. Changes in the canal shape differed significantly between the different instruments in 13 of the 14 measuring points. Drastic undesirable changes in the canal shape (e.g. straightening or zip and elbow) occurred after instrumentation with reamers and K‐files, but these changes were less noticeable after instrumentation with flexible instruments with conventional tips. After instrumentation with flexible instruments with modified tips there were few undesirable changes in shape.The conclusion could be drawn that flexible instruments, especially those with modified tips, were clearly superior to conventional reamers and K‐files with regard to cutting efficiency and instrumentation of curved

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1995.tb00161.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryThe aim of this study was to determine whether radiographs provide an accurate representation of the degree of root canal obturation following a cold lateral condensation technique. A total of 40 extracted single‐rooted lower premolar teeth were prepared using either a standardized step‐back technique or an ultrasonic device by one of two operators. The four groups, each of 10 teeth were obturated using lateral condensation by a third operator. To assess apical leakage the obturated teeth were coated with nail varnish to within 2 mm of the apex and immersed in methylene blue for 48 h. The teeth were then radiographed in bucco‐lingual and mesio‐distal planes prior to subsequent sectioning in a bucco‐lingual plane. Sections and radiographs were analysed using an image analysis apparatus to determine the proportion of root canal occupied by gutta‐percha, void and/or sealer. Mean percentages of void calculated from the bucco‐lingual radiographs, mesio‐distal radiographs and tooth sections were 4.14%, 5.98% and 4.98%, respectively. Statistical analysis showed no significant differences between the radiographic views and the tooth sections (P>0.05). Both planes of radiograph accurately represented the proportion of void when compared with th

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1995.tb00162.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryIn this retrospective study the effects of different kinds of emergency treatments on flare‐ups and other complications were examined. A total of 197 teeth received emergency treatment after diagnosis at the beginning of the root canal therapy; in 103 the pulp chamber was left open for drainage of pus, 35 were treated with dexamethasone sodium phosphate, and 59 with various other medicaments, followed by routine root canal treatment. In all, 404 teeth received root canal treatment without emergency treatment. If symptoms occurred during treatment, flare‐up was said to be present. If a periapical radiolucency was found, long‐term calcium hydroxide treatment was used: no sign of periapical healing radiographically after 6 months was described as a complication. The percentage of teeth with no complications varied from 72.2% (dexamethasone) to 78.9% (other modification) and the results showed no differences between the groups in the teeth with no complications, flare‐ups or other complications. The number of bacteria detected with Gram's staining was higher in the teeth which were left open. In conclusion, leaving the pulp chamber open for drainage had no effect on the incidence of flare‐ups or other comp

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1995.tb00163.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryIn vitrotemperatures produced in the root canal and on the root surface were measured simultaneously as heated gutta‐percha was injected into the prepared canal. The canals were obturated with the Obtura II heated gutta‐percha system with temperature settings of 160, 185, and 200°C. The mean intracanal temperatures ranged from 40.21 to 57.24°C, whereas the mean root surface temperatures were recorded from 37.22 to 41.90°C for all three temperatures tested. The rise in temperature on the root surface was below the critical level of 10°C and should not cause damage to the periodontal l

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1995.tb00164.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryThis paper reports the findings of a survey of a group of general dental practitioners (GDPs) from one region of the United Kingdom. The practitioners were asked to complete a questionnaire investigating their approach to the restoration of root‐filled teeth. A high response rate was achieved and the replies indicated that most practitioners restore teeth within 1 month of completing the root filling. Nonprecious cast alloys cores were popular as was amalgam for core build‐ups. Most practitioners opted for a post which was two‐thirds the length of the root and zinc phosphate was the most popular luting material. Almost one‐quarter of respondents believed that a root is strengthened by a post retained restoration and a similar number have never attended a postgraduate meeting on the subject of the restoration of root‐fil

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1995.tb00165.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryIn this article the question of the relevance and consequences of bacteria remaining in the tubules of root dentine after cleaning and shaping of the root canal space is addressed. A second aim is to discuss the necessity of clinical measures taken to eradicate those bacteria that are presumed to survive there. The available clinical and experimental evidence supports the use of antibacterial dressings in cases where the root canal space remains temporarily unobturated after removal of necrotic and infected pulp tissue. There is no evidence, however, that special measures should be taken to kill the bacteria in the dentinal tubules. Should time permit, a sound obturation technique immediately following the cleaning, shaping and disinfection phases allows the remaining bacteria in the tubules to be either inactivated or prevented from repopulating the (former) canal space. In the vast majority of cases, those bacteria appear not to jeopardize the successful outcome of root canal treatment.

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1995.tb00166.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryThirty single‐rooted teeth were prepared to receive cast posts. After cementation of the post the teeth were divided into three groups. Group I did not receive any treatment, whereas the posts in groups II and III were treated with an ultrasonic device, for 2 min and 5 min, respectively. The force required for post removal was determined using a universal test machine. No statistical differences (P>0.05) were found between the groups where ultrasound had been used.Significantly reduced forces were necessary to remove the posts from group II and III, compared with group I which did not receive ultrasonic treatment (P<0.05

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1995.tb00167.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryA clinical study was carried out on nonvital maxillary central incisors to evaluate the incidence of postoperative pain following single‐visit root canal treatment using three different instrumentation techniques. Ninety teeth from 78 patients whose ages ranged from 14 to 63 years were selected and divided into three groups. Each group (30 teeth) was prepared by a different coronal‐to‐apical technique using different instrument movement depending upon the technique employed: modified double‐flared, crown‐downpressureless and balanced force techniques. No difference was observed in the incidence of postoperative pain among t

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1995.tb00168.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1995.tb00169.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY