摘要:

Summary.Using selective agonists and antagonists of alpha, adrenoceptors, attempts were made to identify the subtype alphaj adrenoceptors in the blood vessels of the canine dental pulp. In chloralose‐anaesthetized dogs, intra‐arterial administration of noradrenaline and guanabenz in different doses produced a dose‐related pulpal vasoconstriction which was measured using hydrogen‐gas clearance. The vasoconstrictor response to noradrenaline was inhibited by phentolamine, a non‐selective alpha adrenoceptor antagonist. The response to guanabenz was inhibited by rauwoiscine, a highly selective alpha, adrenoceptor antagonist. The results demonstrated that alpha, adrenoceptors are present in the blood vessels of dog de

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1991.tb00137.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary.Acoustic microstreaming is known ro be an important phenomenon associated with the use of clinically available cndosonic systems. However, it has proved difficult to calibrate its pattern and effectiveness around the oscillating file. Anin‐vitromodel system consisting of slow setting plaster was developed to demonstrate the activity of streaming around both ultrasonically and sonically activated files. For ultrasonic files, streaming occurred mainly in front of and behind the file, in contrast to the sonic file, where the plaster was disturbed evenly around it. With both types of file most activity occurred around the file tip, and became reduced towards the driver. Streaming patterns associated with the ultrasonic device were found to be dependent on the power setting of the instrument and whether the side of the file was constrained or lightly touched. The sonic device produced a large disturbance around the freely oscillating tip. Under load this streaming occurred along the whole length of the file, and was unaffected by constraint. This investigation demonstrated that streaming does occur with the instruments currently available, although it is dependent on their operating conditions. Clinical users of such equipment should be aware of the characteristic three‐dimensional patterns of streaming that occur around these endosonic files, in order to maximize their efficie

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1991.tb00138.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary.The dispiacement amplitude of endosonic files was measured with the aid of light microscopy in order to determine the power output of different ultrasonic units. The results showed that there was a substantial difference in the displacement amplitudes when the same size of file was used in different ultrasonic units made by the same or different manufacturers. File fracture was found to be a problem when files were driven at high displacement amplitudes.

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1991.tb00139.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary.Many studies have investigated the presence of nerve fibres in the coronal odontoblast layer of mature teeth. However, little information is available on the presence of these structures in immature human teeth. The pulps of 18 human maxillary and mandibular third molars at various stages of development were collected, sectioned, and stained by the immunoperoxidase technique. The results showed the presence of numerous myelinated nerve fibres in the coronal odontoblast layer of teeth with fully formed roots. Similar observations were made in teeth with half formed roots, and in those without roots. On the basis of these results, it appears that a lack of response to vitality tests in teeth with incompletely formed roots is not wholly due to the absence of nerve fibres in the coronal odontoblast layer.

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1991.tb00140.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary.The root canals of 30 extracted human teeth with single canals were prepared biomechanicaliy with hand instruments using a flaring technique. Three different irrigation regimes were used, with and without ultrasonic activation of a root canal file. The six irrigation sequences used in this study were as follows: Savlon. Savlon with ultrasound, EDTAC/NaOCl/ EDTAC, EDTAC/NaOCI/EDTAC with ultrasound, NaOCl/EDTAC/NaOCi, and NaOCl/EDTAC/NaOCl with ultrasound. Scanning electron microscopic (SEM) examination of the prepared root canal walls showed a complete smear layer when Savlon was used. Ultrasound reduced the amount of smear with Savlon, but did not do so significantly with the other irrigation regimes. The most effective irrigation regime for removing smear layer and other debris was EDTAC/NaOCl/EDTAC. In all groups there was a significant decrease in cleaning efficiency as the apical end of the canai was approached.

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1991.tb00141.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary.The aim of this study was to evaluate the effect of surface demineralization on the healing of 120 replanted teeth in fifteen 8‐ to 16‐month‐old dogs. Replanted teeth were divided into two groups (A and B). In group A, teeth were replanted following planing of the entire root surface. In group B, teeth were replanted following planing and surface demineralization with citric acid. Replanted teeth were splinted for 7 days, and observation periods were 3, 14 and 56 days. A total of 95 teeth and their surrounding tissues were examined histologically under a light microscope.Histological examination of specimens 3 days after replantation revealed that initial reunion between the root and the alveolar periodontal ligament fibres was via a fibrin‐like network in both groups. Fourteen days after replantation histologiesl observations showed superior healing in group B with regard to epithelial condition, periodontal ligament fibre reattachment to the root surface, resorption and functional arrangement of the periodontal ligament fibres. By 56 days after replantation, healing was superior in group A; group B was characterized by severe inflammatory and replacement resorption. These results indicated that surface demineralization had an initial positive effect, but later led to impaired

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1991.tb00142.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Summary.An unusual case of a persistent infection related to a root‐filled tooth is reported. Microscopical evaluation revealed the cause to be a large mass ofActmomyees‐like filaments, and microbiological culture yielded a low level ofActiaomyces israelii. The significance of such a presentation is discus

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1991.tb00143.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1991.tb00144.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Book review in this article:Surgical Endodontics. Colour Manual.I. E. Barnes.

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1991.tb00145.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0143-2885    

DOI:10.1111/j.1365-2591.1991.tb00146.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY