摘要:

Summary.Gnotobiotic rats mono‐infected withStreptococcus mutans(NCTC 10919) were maintained on a high sucrose diet in an isolator. When they were 8 weeks old the pulps of their maxillary first and second molars were mechanically exposed and left open to the oral environment. The rats were sacrificed in groups after 7 and 28 days. Thirty‐seven teeth were available for study in the 7‐day group, and 30 teeth in the 28‐day group. The testS. mutanswas non‐cariogenic. After 7 days, necrosis of the superficial layers of the pulp was noted; however, after 28 days pulpal necrosis was much more extensive and calcific repair was observed in only one‐third of the teeth examined. The microorganism did not provoke inflammation in the pulp or periapical tissues. This is the second strain ofS. mutanstested in this manner. These results are very similar to those reported previously forS. mutans(NCTC 10449) and strengthens the view that organisms of theS. mutansgroup have a low pathogenicity f

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1989.tb00498.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary.The antibacterial activity of four elements (zinc, copper, fluoride and mercury), previously reported to be released from dental restorative materials, was investigated. This was carried out using two aerobic micro‐organisms isolated from dentine beneath cavities in the ferret. These were grown in the presence of the test elements over a concentration range of 10–100 μg/ml for 72 hours. Concentration and exposure time were found to have a highly significant effect on the growth and viability of both micro‐organisms. Zinc, mercury and copper exerted the greatest effect, fluoride the

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1989.tb00499.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary.The root canals of 120 single rooted teeth were prepared with files and then divided randomly into twelve subgroups. Four operators each filled three of these subgroups, one group with laterally condensed gutta‐percha, one group with thermoplasticized gutta‐percha with sealer and one group with thermoplasticized gutta‐percha without sealer. The fillings were assessed radiographically and a dye penetration test was used to investigate the leakage.The lowest leakage values were found in those canals filled with laterally condensed gutta‐percha. The sealing ability of thermoplasticized gutta‐percha was enhanced by the use of a sealer. There was greater variation between operators in those groups where thermoplasticized gutta‐perc

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1989.tb00500.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary.To compare the effectiveness of different irrigation procedures on the removal of the smear layer, 40 curved canals were manually preparedin vitrounder copious irrigation with 3 percentb NaOCI. Ten canals served as controls. The remaining 30 were equally distributed in three experimental groups and subsequently irrigated with the following: ultrasound with EDTA. In the scanning electron microscope, the appearance of the smear layer was rated over sthe distribution of dentinal tubule openingls for the coronal, middle and apical segmentsl of the canals. Irrigation with NaOCl produced consistently smeared surfaces. Ultrasonic stirring of NaOCl removed the smear layer moderately, while EDTA produced almost smear‐free surfaces. Ultrasound in association with EDTA did not enhance the dissolving capability of this chelating agent. A definite decline in the efficiency of the irrigation procedures was also observed along the apical part of the canal

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1989.tb00501.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary.The results of the endodontic management of root rsorption in 77 transplanted teetharedescribed. Apical bny radiolucelncy healed in 75 per cent of cases but the prognosis for root resorption was poorer; in only 34 per cent of cases was the resorption arrested. Various factors which might have influendced the outcome of treatment are discussed

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1989.tb00502.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Summary.Traditional teaching of the anatomy of root canals in different teeth can lead clinicians into the misguided belief that a predetermined number of root canals is always present in any given tooth. A new understanding of the root canal system has enabled the location of additional canals.Results of the clinical study of 760 first mandibular molars, showed that 20 (2.6 per cent) had three canals in the mesial root. Of these 20 teeth, 13 (65 per cent) had an intermediate canal which joined the mesiobuccal canal in the apical third. In six cases (30 per cent) it joined the mesiolingual canal in the same area. In only one case did the intermediate or third canal retain its individual nature and end in an independent foramen.

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1989.tb00503.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Book reviewed in this article:Problem Solving in Endodontics, Prevention, Identification and ManagementJames L. Gutmann, Thorm C. Dumsha and Paul E. Lovdahl.

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1989.tb00504.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1989.tb00505.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY