bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decision support systems: barriers and farmers’ need for support*
Authors: Jørgensen L. N. , Noe E. , Langvad A. M. , Jensen J. E. , Ørum J. E. , Rydahl P. 
Published: September 2007

The highly complex knowledge of scientific disciplines makes nuanced analysis and modelling possible. However, the information produced often does not reach farmers because it is presented in a way that does not correspond to the way their work is carried out in practice. The decision support system Crop Protection Online is widely used by advisors and as a learning tool for students. Although the system has been validated in many field trials over the years and has shown reliable results, the number of end‐users among farmers has been relatively low during the last 10 years (approximately 1000 farmers). A sociological investigation of farmers’ decision‐making styles in the area of crop protection has shown that arable farmers can be divided into three major groups: (a) system‐orientated farmers, (b) experience‐based farmers and (c) advisory‐orientated farmers. The information required by these three groups to make their decisions varies and therefore different ways of using decision support systems need to be provided. Decision support systems need to be developed in close dialogue and collaboration with user groups.
A modification of the Millipore method for screening restorative materials
Authors: MERYON SYLVIA D. , STEPHENS P. G. , BROWNE R. M. 
Published: September 2007

SummaryThe cytotoxic effects of Concise composite, zinc phosphate and silicate cements, and zinc oxide/eugenol were evaluated in an in vitro system which ensured good cell/material contact. The material contact. The materials were incubated for increasing lengths of time, and their toxicity as assessed by their effect on SDH staining ranked them in order of increasing severity Concise < Silicap < zinc phosphate < zinc oxide/eugenol. On the basis of cellular morphology Silicap was more toxic than zinc phosphate. Overall there was poor correlation between these two methods of assessment. A layer of compacted dentine powder between the test material and cell monolayer reduced the cytotoxic effects of all materials.This study was supported by a grant from D.H.S.S., No. R/E 1050/105. The authors are grateful to Dr Buchan, Department of Medical Microbiology for the initial supply of cells, to the photography unit in preparing figures and to Miss H. Rupp for typing the manuscript.
Effect of implantaton of AH26 silver‐free in subcutaneous tissue of guinea‐pigs
Authors: TAGGER M. , TAGGER ETTY 
Published: September 2007

Summary. Twenty‐five polyethylene tubes filled with AH26 sealer, regular or silver‐free, were implanted subcutaneously in the backs of seven young guinea‐pigs. The tissue reactions were studied after 2 months and evaluated for the amount of inflammation and fibrosis present at the openings of the tubes. The differences between the two sealers were minor.In almost one‐half of the specimens, some sealer was present outside the tubes and the reaction around these clumps was more severe than at the openings of the tubes. In this respect, the trend of a stronger reaction to AH26 with silver was more noticeable.The reduced dentine‐staining potential of the silver‐free sealer, combined with its slightly smaller irritational potential, should make it preferable to the regular one if its physical properties are not inferior.
Scanning electron microscpe study comparing the effecacy of endodontic irrigating systems
Authors: ALAÇAM T. 
Published: September 2007

Summary. Thirty‐five single rooted teeth were biomechanically instrumented with salaine, following' which they were subjected to different methods of irrigation. Four groups of teeth were irrigatied using and Endomate unit with NaOCl in combination with H2O2, or EDTA, or glutaraldehde or saline.Two groups were irrigated with 5 per cent NaOCl in combination with ultrasound; one of them was further irrigated with 3 per cent H2O2 using the Endomate system.The control group was irrigated with NaOCl and H2O2 using the conventional technique. The prepared root canals were examined for the presence of smear layer under SEM.All groups irrigated with the ultrasonic technique and the group irrigated with the endomate system using EDTA solution showed significantly cleaner surfaces; the smear layer was also greatly reduced.
The heat generated on the external root surface during post space preparation
Authors: SAUNDERS E. M. , SAUNDERS W. P. 
Published: September 2007

Summary. The heat generated on the external root surface of human premolar teeth during post space preparation was measured in vitro. The rise in temperature was recorded at a point 6 mm from the apex of the tooth using a thermocouple attached to a chart recorder. The temperature rise was greatest when the removal of gutta‐percha was combined with post channel preparation. Temperature rises of up to 31°C were recorded. Instruments that only removed gutta‐percha did not generate the same amount of heat.The results from this study suggest that the use of engine‐driven drills to prepare post channels in teeth may generate temperature rises that may cause periradicular tissue damage, and caution should be exercised during their use.
Digital image analysis for the diagnosis of periapical bone lesions: a preliminary study
Authors: MOL A. , VANDER STELT P. F. 
Published: September 2007

Summary. Digital image analysis techniques enable the problem of examiner variability to be circumvented, and can be used to develop quantitative descriptions of bone lesions. This study investigated a method for describing periapical bone lesions.An edge‐detection technique was developed for application to routine periapical radiographs. Most periapical bone lesions appear radiographically as dark areas compared with the surrounding tissues. The digital imaging process resulted in an outline resembling the contour of the image of the lesion present. This contour could be successfully projected on to the original image with only limited operator assistance.Processing of the image resulted in increased definition of the structures present, with considerable noise reduction. The result was a simplified diagnostic examination process that promised a high degree of objectivity in periapical bone lesion detection.It is concluded that the results encourage further development of image processing techniques suitable for the definitive detection and diagnosis of periapical bone lesions.
Root canal anatomy of mandibular second molars. Part I
Authors: MANNING S. A. 
Published: September 2007

Summary. The root canal anatomy of 149 mandibular second molars was studied using a technique in which the pulp was removed, the canai space filled with black ink and the roots demineralized and made transparent. Of the 149 teeth, 22 per cent had single roots, 76 per cent had two roots and 2 per cent had three roots. In the single‐rooted teeth, three canals were most common, while in the mesial root of the two‐rooted teeth, two canals that joined near the apex and one canai in the distal root were most frequent. Round canals were most common in two‐rooted teeth and C‐shaped canals in single‐rooted teeth. Transverse anastomoses were found in 33 per cent of roots, most commonly in the middle third of the root. Lateral canals were found in 72 per cent of roots, most commonly in the apical third of the root. The apical foramen was positioned at the apex in only 33 per cent of roots, and apical deltas were found in 35 per cent.The patient's age and race affected canal shape, with more round canals present in patients over 35 years of age, and more C‐shaped canals in Asians. The sex of the patient and the side of the mouth affected the presence of apical deltas, with more being found in males and on the left side. Single‐rooted teeth had more complex root canal systems than two‐rooted teeth, with more lateral canals, transverse anastomoses, apical deltas and C‐shaped canals.
Tissue response to glass ionomer retrograde root fillings
Authors: FORD T. R. PITT , ROBERTS G. J. 
Published: September 2007

Summary. The periapical tissue response to glass ionomer cement retrograde root fillings was investigated both in the presence and in the absence of fillings in the root canals of eight upper incisor teeth of four monkeys. The pulps of the teeth were extirpated and one canal in each pair was filled with laterally condensed gutta‐percha immediately after canal preparation. The other canal was prepared but left open to oral contamination. Apicectomies were performed on both teeth in each pair 1 week later, and glass ionomer cement retrograde root fillings were placed. After 5 months, the teeth and surrounding tissues were removed and prepared for histological examination.All four of the teeth without root canal fillings showed severe periapical inflammation, and bacteria were present in the interface between the dentine and the retrograde root filling. The teeth with root canal fillings showed or no periapical inflammation.This study showed that adhesive retrograde root fillings were successful when the root canal was completely filled, but in the absence of a guttapercha canal filling they failed to provide a seal.
The effects on the dental pulp of a composite resin and two dentine bonding agents and associated bacterial microleakage
Authors: GRIEVE A. R. , ALANI A. , SAUNDERS W. P. 
Published: September 2007

Summary. The pulpat reaction associated with a composite resin alone and composite resin used in conjunction with two dentine bonding agents was studied. Class V cavities were prepared on the labial surfaces of the canine teeth of 18 male ferrets. After acid etching of the enamel margins, the cavities were restored with either a composite resin alone or in combination with one of two dentine bonding agents, Scotchbond and Gluma. One cavity in each animal was filled with Kalzinol as a control. The animals were killed after 7, 14 and 28 days. After histoiogicat processing, the pulpal changes were assessed qualitatively and quantitatively according to standard criteria.There were variations in the pulpal response at all time intervals. The responses to the two dentine bonding agents were similar to those found with composite resin alone. No pulpal inflammation was observed in the control teeth. Gram‐positive micro‐organisms were identified at the interface of restoration and cavity wall, or within the dentinal tubules in virtually all cases in which pulpal inflammation was observed.
The effect of post space preparation on the apical seal of root fillings using chemically adhesive materials
Authors: SAUNDERS E. M. , SAUNDERS W. P. , RASHID M. Y. A. 
Published: September 2007

Summary. The effect on the apical seal of root filling teeth with two sealer cements that reacted chemically with tooth structure was studied in vitro. In addition, apical leakage of teeth obturated with these materials and subsequently prepared to accept a post was tested. Ninety single‐rooted teeth with mature apices were prepared chemomechanically by the stepback technique using files and copious irrigation with 2.5 per cent sodium hypochlorite. The teeth were then randomly allocated to six groups of 15 teeth each. Two groups were root filled by lateral condensation of gutta‐percha and one of three sealer cements: Tubliseal, a radiopaque glass ionomer luting cement, Ketac Cem, and a chemically active composite resin, Panavia Ex. Thirty minutes later, in one group for each material, a post space was prepared leaving 4–5 nun of root filling at the apex. The extent of apical leakage in each group was determined after immersion in Indian ink for 14 days. The teeth were demineralized, dehydrated and immersed in methyl salicylate, which rendered them transparent, and a linear measurement of dye penetration was recorded.No statistically significant difference in the extent of leakage was found between the sealers in those groups which were filled by lateral condensation and left intact. However, the degree of leakage increased after post space preparation with the glass ionomer and Tubliseal groups, but was reduced in the Panavia Ex group.
The adaptation and sealing ability of light‐cured glass ionomer retrograde root fillings
Authors: CHONG B. S. , FORD T. R. PITT , WATSON T. F. 
Published: September 2007

SummaryThe adaptation and sealing ability of a light‐cured glass ionomer cement when used as a retrograde root filling was assessed using a confocal optical microscope with and without a fluorescent dye. This material was compared with a conventional glass ionomer cement and amalgam. The root canals of 60 extracted human single‐rooted teeth were prepared and filled with gutta‐percha and sealer. All the teeth were apicected, retrograde cavities were prepared, and then divided into three groups of 20 teeth each and filled with the test materials. The light‐cured glass ionomer cement was well adapted to the retrograde cavity and apicected root surface. Within the retrograde cavity the cement was often well adapted to one wall, but gaps were found on the opposite cavity wall. This was probably caused by the polymerization contraction of the material. In contrast, the amalgam retrograde root fillings were poorly adapted to the cavines, with gaps between the cavity walls and amalgam. This group exhibited the poorest sealing ability as measured by the extent of dye penetration. The conventional glass ionomer cement was often found smeared over the root face, and there were unfilled voids at the base of some retrograde cavities. The results of the dye leakage study were analysed statistically The sealing ability of the light‐cured glass ionomer cement was significantly better than that of amalgam (P < 0.001). The dye penetration around the light‐cured glass ionomer cement and the conventional glass ionomer cement was not significantly different (P > 0.05). However, the sealing ability of the conventional glass ionomer cement was significantly better than that of amalgam (P < 0.05).
Toxicity of Pulpispad using four different cell types
Authors: PISSIOTIS E. , SPÅNGBERG L. S. W. 
Published: September 2007

SummaryThe cytotoxic effect of a zinc oxide‐eugenol‐based paste (Pulpispad) was evaluated in vitro after setting for 1 day and 1 week. Target cells were L929 cells, gingival, periodontal ligament and pulpal fibroblasts. The material was incubated with the cells for 4 and 24 hours, and its toxicity was evaluated with the 51Cr‐release method. Puipispad was highly cytotoxic to all cell lines even after setting for 1 week. The use of Pulpispad is not recommended for future clinical application. The various responses among the four cell lines indicated that diploid cell lines can, under certain circumstances, be less sensitive than aneuploid cell lines. It is therefore suggested that in the evaluation of biomaterials the choice of cell lines should be carefully considered, as they can display varying sensitivities.
One‐appointment root canal treatment: incidence of postoperative pain using a modified double‐flared technique
Authors: FAVA L. R. G. 
Published: September 2007

SummaryA clinical study of maxillary central incisors was conducted in order to evaluate the incidence of postoperative pain following one‐appointment root canal treatment using a modification of the double‐flared technique to prepare the root canal system. Sixty teeth with necrotic pulps, from 52 patients whose ages ranged from 10 to 53 years, were inciuded. Half of the teeth were prepared by the double‐flared technique, while the other half were prepared by a modification of this technique. No difference was observed in the incidence of postoperative pain between the two groups.
Blood flow changes in the dental pulp during limited exercise measured by laser Doppler flowmetry
Authors: WATSON A. D. M. , PITTFORD T. R. , McDONALD F. 
Published: September 2007

SummaryThe effect of limited exercise on pulpal blood flow was assessed by laser Doppler flowmetry (LDF). The primary aim of the investigation was to determine whether clinically significant changes could be induced by mild exercise when LDF was used to monitor pulpal blood flow.Blood flow readings were obtained from the coronal pulps of 17 upper central incisor teeth of 10 human volunteers before, during and after limited exercise. Readings were also obtained from the adjacent attached gingivae. Pulse rate was recorded concurrently. Pulpal Mood flow was found to vary during exercise, with a mean percentage change of 38% from the level at rest; the range was from a 100% decrease to a 2 00% increase. The mean percentage increase in gingival blood flow was 65%, with a range of 6–300%. The main indication that blood flow was being assessed was the pulsatile nature of the output. Results were compared only within individual teeth. The pulse rate increased during exercise (mean percentage increase 54%, range 11–98%). There was no direct relationship between increased pulse rate and pulpal Mood flow. It was evident that the mechanisms controlling pulpal and gingival blood flows differed.Laser Doppler flowmetry readings were only repro‐ducible in individual teeth provided that the patient was at rest, and this should be taken into account in clinical or research measurements.
The role of intracanal medication in root canal treatment
Authors: CHONG B. S. , FORD T. R. PITT 
Published: September 2007

SummaryThe role of intracanal medication as a root canal dressing is re‐examined. In pulpectomy and some root canal treatments, where the root canal contains vital pulp tissue, it is doubtful whether a routine intracanal medicament is needed.In infected root canals, intracanal medication has been advocated for many purposes. An intracanal medicament is used to:

(i) eliminate any remaining bacteria after canal instrumentation;
(ii) reduce inflammation of periapical tissues and pulp remnants;
(iii) render canal contents inert and neutralize tissue debris;
(iv) act as a barrier against leakage from the temporary filling;
(v) help to dry persistently wet canals.

However, most of the indications for intracanal medicaments are questionable.Intracanal medicaments should only be used for root canal disinfection as part of controlled asepsis in infected root canals, and their role is secondary to cleaning and shaping of the root canal. Thorough canal debridement and adequate canal preparation are more pertinent, and their importance is emphasized. Bacteriological sampling may be necessary if a tooth does not respond to treatment, to help in the choice of intracanal medicament.
Cell responses to Hydron by a new in‐vitro method
Authors: MCNAMARA J. R. , HEITHERSAY G. S. , WIEBKIN O. W. 
Published: September 2007

SummaryAn in‐vitro biotoxicity test system, suitable for the assessment of endodontic filling materials, has been developed and used to test cell responses to Hydron, AH26 and Tubliseal. A robust, well‐characterized and stable cell line (L‐cells) which was grown as uniform cultures on Miliipore filters, has been used as indicator cells. As they approached confluence they were exposed to test substances for 24 h and biosynthetic activities were measured. The test system is a modification of that described by Wennberg et al. (1979). By inverting the cultures on organ‐culture rafts, cells were separated from the test material, which was placed on top of the Miliipore filters. Freshly mixed polymerizing Hydron and prepolymerized Hydron were tested. The cell responses were compared with those of cultures exposed to freshly mixed AH26 and Tubliseal. Polymerizing and prepolymerized Hydron depressed both cell division, assessed by 3H‐thymidine incorporation, and the synthesis and secretion of matrix material as measured by precipitable 35S‐sulphate. Prepolymerized Hydron decreased cell functions by 59% and 56% of live cell controls, respectively, while the freshly mixed polymerizing Hydron inhibited biosynthesis by 89% and 94%, respectively. The data for polymerizing Hydron were compared with results for other root‐filling materials and showed similar values to those for Tubliseal (92% and 95%), but greater inhibition of biosynthesis than for AH26 (53% and 50%). The AH26 values were similar to those obtained from cultures exposed to the prepolymerized Hydron. Recovery of biosynthetic capacity by these cultures after removal of all endodontic material was also assessed. Partial biosynthetic recovery of cell cultures was observed 24 h after removal of prepolymerized Hydron. The unpolymerized Hydron continued to yield a soluble component which substantially depressed biosynthetic activity of the experimental cultures up to 14 days. In general, the results indicated that Hydron, particularly in its freshly mixed state, when not in actual cell contact, depressed cell division and extracellular‐matrix synthesis. Data derived from similar in‐vitro testing with AH26 and Tubliseal revealed that they both inhibited cell division and matrix synthesis. Tubliseal inhibited these cell responses to the same extent as polymerizing Hydron. Polymerizing Hydron was significantly more toxic than AH26, while there were no significant differences in the levels of toxicity of polymerized Hydron and AH26.
Comparison of three imaging techniques for assessing endodontic working length
Authors: GRIFFITHS B. M. , BROWN J. E. , HYATT A. T. , LINNEY A. D. 
Published: September 2007

SummaryThe accuracy of endodontic working length estimation was investigated using three imaging techniques: radiography (Rd), Xeroradiography (Xr) and Radiovisiogra‐phy (RVG positive and negative prints). An in‐vitro model of extracted single straight roots, mounted in wooden blocks with wax, was employed in the study. Optimum exposures were established for each of the imaging techniques. The magnification of the images was measured and the resolution of the RVG images was also investigated. Comparable Rd (D‐speed film). Xr, RVG positive and RVG negative images were made of five roots with size 10 files in situ. Images of 10 standard files were made, ranging from 2.0 nun through the root apex to 2.5 mm short of the apex, resulting in 200 images. Six observers each assessed the working distance on 100 images, measuring the distance from the apical foramen to the file tip. After allowing for the magnification of the images, these results were compared with the‘true’file tip to apical foramen (measured with the aid of a reflex microscope). The inaccuracy of working distance estimations was considered to be of clinical significance (> 0.5 mm) in 6% of measurements made from Rd and Xr, 19.2% of measurements from RVG negative and 32.3% from RVG positive images. In addition, 14% of RVG images were too poorly defined to be assessed. The first‐generation RVG system was used in this study. It was therefore concluded that the most accurate estimates of working distance were made from Xr and Rd images, and that RVG images, particularly the RVG positive images, were the least accurate and most difficult to read. In comparison with radiographs using D‐speed film, a reduction in radiation exposure of 10% was made for Xr and of 60% for RVG. This was considered to be of clinical significance, and would be particularly important if the resolution of the RVG prints were to be improved by further development of the RVG system.