bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endodontic treatment performed by Flemish dentists. Part 2. Canal filling and decision making for referrals and treatment of apical periodontitis
Authors: Hommez G. M. G. , De Moor R. J. G. , Braem M. 
Published: May 2003

AbstractAim  To gather information on root‐canal treatment carried out by dentists working in Flanders (Belgium).Methodology  A questionnaire reported in a previous study was also used to gather information on canal medicaments, canal filling, and in decision making for referrals and treatment of apical periodontitis.Results  Calcium hydroxide as an interappointment dressing was used by 69.7% of the respondents. Approximately one‐third of the respondents did not use any intracanal medicament. Caustic products used for pulp tissue fixation were used by 66.8% of the respondents. Cavit® (48.2%) and glass‐ionomer (31.3%) were the temporary coronal‐filling materials used most often, followed by zinc oxide–eugenol and IRM®. Cold lateral condensation of gutta‐percha was the filling technique most used by the respondents (65.8%). Single‐cone gutta‐percha placement (16%), paste techniques (4.9%) and silver points (3.9%) were still used. Resin‐based sealers were used most often (88.6%). Paraformaldehyde containing sealers such as Endomethasone and N2 were used infrequently. Approximately half of the practitioners were satisfied with their canal‐filling technique, others felt that they could do better (43.0%); 0.7% were not satisfied. In cases with apical periodontitis, the size of periapical lesions and/or the presence of a root filling influenced the choice of endodontic treatment. The most common reasons for referral of endodontic cases were: retrieval of silver points, surgery, and post removal.Conclusions  The results of this study indicate that techniques and methods used for canal medication and canal filling were acceptable for the majority of the respondents. Re‐treatment was underestimated as a treatment option.
Induction of interleukin‐6 gene expression by pro‐inflammatory cytokines and black‐pigmented Bacteroides in human pulp cell cultures
Authors: Yang L.‐C. , Tsai C.‐H. , Huang F.‐M. , Liu C.‐M. , Lai C.‐C. , Chang Y.‐C. 
Published: May 2003

AbstractAim  To investigate the effect of pro‐inflammatory cytokines and black‐pigmented Bacteroides on the expression of IL‐6 gene in human pulp fibroblasts.Methodology  IL‐1α, tumour necrosis factor‐α (TNF‐α) and the supernatants of Porphyromonas endodontalis, P. gingivalis and Prevotella intermedia were used to evaluate IL‐6 gene expression in human pulp fibroblasts. The levels of mRNAs were measured by the quantitative reverse‐transcriptase polymerase chain reaction analysis.Results  Investigations of the time dependence of IL‐6 mRNA expression in pro‐inflammatory cytokines‐treated cells revealed a rapid accumulation of the transcript after 2 h of exposure and remained elevated throughout the 24‐h incubation period. In addition, black‐pigmented Bacteroides also induced IL‐6 gene expression in human pulp fibroblasts.Conclusions  Pro‐inflammatory cytokines and black‐pigmented Bacteroides may be involved in developing pulpal inflammation through the stimulation of IL‐6 production.
A comparative study of root canal preparation using FlexMaster and HERO 642 rotary Ni–Ti instruments
Authors: Hülsmann M. , Gressmann G. , Schäfers F. 
Published: May 2003

AbstractAim  To compare several parameters of root canal preparation using two different rotary nickel–titanium (Ni–Ti) instruments: FlexMaster (VDW, Munich, Germany) and HERO 642 (Micro‐Mega, Besançon, France).Methodology  Fifty extracted human mandibular molars with root canal curvatures between 20 and 40° were embedded into a muffle system. All root canals were prepared to size 45 using a high‐torque motor with two different Ni–Ti instruments, FlexMaster and HERO 642. In both groups, irrigation was performed with 2 mL NaOCl (3%) after each instrument size. RC‐Prep (Premier, Philadelphia, USA) was used as a chelating agent with each instrument. The following parameters were evaluated: straightening of curved root canals, postoperative root canal diameter, working safety (file fractures, perforations, apical blockages, loss of working length), cleaning ability and working time. Statistical analysis was performed using the Wilcoxon's test (P < 0.05) for straightening and Fishers's exact test (P < 0.05) for comparison of cross‐sections, contact between pre‐ and postoperative diameter, root canal cleanliness and working time.Results  Both Ni–Ti systems maintained the curvature well: the mean degree of straightening was 0.6° for FlexMaster and 0.5° for HERO 642. One file was fractured with the FlexMaster system, but further procedural incidents were not recorded. Following preparation with FlexMaster, 18% of the root canals had a round diameter, 53% an oval diameter and 29% an irregular diameter; HERO 642 preparations resulted in a round diameter in 25%, oval shape in 47% and irregular cross‐sections in 28% of the cases. Mean working time was shorter for HERO 642 (66.0 s) than for FlexMaster (71.1 s). Cleanliness of the root canal walls was investigated under the SEM using 5‐score indices for debris and smear layer. For debris, HERO 642 and FlexMaster achieved 73 and 70% scores of 1 and 2, respectively. The results for smear layer were similar: HERO 642 and FlexMaster achieved 33 and 26% scores of 1 and 2, respectively. Significant differences between the two systems were not detected for any of the parameters evaluated.Conclusions  Both systems respected original root canal curvature well and were safe. Both systems failed to remove debris and smear layer in the majority of the cases.
In vitro evaluation of apical microleakage following canal filling with a coated carrier system compared with lateral and thermomechanical gutta‐percha condensation techniques
Authors: Boussetta F. , Bal S. , Romeas A. , Boivin G. , Magloire H. , Farge P. 
Published: May 2003

AbstractAim  The apical sealing ability of a coated carrier system was evaluated in extracted human teeth and compared with lateral and thermomechanical condensation techniques using dye penetration.Methodology  Sixty‐four extracted single‐rooted teeth were instrumented to an apical size 30 using 4% taper Hero 642™ instruments (Micromega, Besançon, France). The sample was divided into three experimental groups. Twenty teeth were randomly obturated with lateral condensation, 20 with thermomechanical compaction and 20 teeth with the Herofill™ Soft‐Core system. Four teeth were used as positive and negative controls. The teeth were covered with nail varnish up to 2 mm from the apical foramen and immersed in a 2% aqueous methylene blue dye solution for 1 week and then washed, dehydrated and embedded in resin. The apical 1 mm of each tooth was removed to reveal the apical limit of the preparation. Transverse sections of the teeth were taken at 500, 1000 and 1500 µm from this point and evaluated for apical leakage. Significant differences between the preparations were analysed with a semiautomatic analyser and the ratio of the dye‐penetrated surface to the total dentinal surface was calculated.Results  Statistical analysis of the results demonstrated significantly less leakage for the Herofill™ Soft‐Core system compared to lateral condensation in terms of total mean dentinal surface and at the 500 µm level. No other differences were noted between Herofill™ Soft‐Core and thermomechanical or lateral condensation, either for the total mean value or at each level.Conclusions  The Herofill™ Soft‐Core system was a reliable obturation system in the apical portion and compared favourably with other gutta‐percha filling techniques.
Endodontic treatment of developmental anomalies in posterior teeth: treatment of geminated/fused teeth – report of two cases
Authors: Tsesis I. , Steinbock N. , Rosenberg E. , Kaufman A. Y. 
Published: May 2003

AbstractAim  Gemination or fusion is a rare occurrence in the mandibular posterior teeth. Endodontic treatment of these teeth needs special care and attention to the bizarre anatomy. The aim of this article is to describe the problems encountered and the strategy in treating such cases.Case report  Two cases of complex endodontic treatment of fused/geminated teeth are presented. The first is an 11‐year‐old girl with an anomalous ‘double’ first mandibular molar and premolar diagnosed as having necrotic pulp with chronic apical abscess of endodontic origin; the second is a 16‐year‐old boy with ‘double’ second and supernumerary mandibular molars, who was diagnosed with irreversible pulpitis. Both cases were treated successfully in multiple appointments. The common features and treatment modalities are discussed.Key learning points

Failure to diagnose fused/geminated teeth leads to misdiagnosis and a treatment plan that could cause permanent damage and tooth loss.
Generally, there is communication between root canal systems of fused/geminated teeth which should be treated as one entity.
Use of magnification is an important aid during treatment.
Review of the current status of tooth whitening with the walking bleach technique
Authors: Attin T. , Paqué F. , Ajam F. , Lennon Á. M. 
Published: May 2003

AbstractInternal bleaching procedures such as the walking bleach technique can be used for whitening of discoloured root‐filled teeth. The walking bleach technique is performed by application of a paste consisting of sodium perborate‐(tetrahydrate) and distilled water (3% H2O2), respectively, in the pulp chamber. Following a critical review of the scientific literature, heating of the mixture is contra‐indicated as the risk of external cervical resorption and the formation of chemical radicals is increased by application of heat. An intracoronal dressing using 30% H2O2 should not be used in order to reduce the risk of inducing cervical resorption. This review provides advice based on the current literature and discusses how the walking bleach technique can lead to successful whitening of non‐vital root‐filled teeth without the risks of side‐effects.
Endodontic and surgical treatment of a geminated maxillary incisor
Authors: Braun A. , Appel T. , Frentzen M. 
Published: May 2003

AbstractAim  A geminated maxillary incisor required complex multidisciplinary treatment to preserve health and restore aesthetics. This report describes the coordination of coronal division, root extraction, bone grafting, endodontic treatment and orthodontics in achieving treatment goals. It is the intention of this report to show how a difficult case could be managed by properly coordinated multidisciplinary care.Summary  Pulp testing of the geminated central right maxillary incisor gave a normal response. Radiographic investigation indicated a connection of the pulp chambers. Both the mesial and distal root were filled with gutta‐percha. The connection between the two root canals was sealed with a flowable dentine‐bonded resin. After dividing the crown with a diamond bur, the mesial part of the tooth was removed and the extraction socket was filled with beta‐tricalcium phosphate ceramic (Cerasorb™). Radiographs taken immediately after surgery and after 6 months showed no periodontal or periapical lesions. No signs of external resorption were identified. The diastema between the central incisors was closed by orthodontic treatment.Key learning points

Geminated teeth may present aesthetic and functional problems which require multidisciplinary care.
Careful clinical and radiographic examination is essential to decide on the fate of the coronal and root halves involved.
A proper coordination between endodontic and surgical treatment may result in maintaining one tooth half, even if a midroot connection between the pulp chambers becomes evident.
Orthograde endodontic treatment, hemisection and orthodontics may solve the aesthetic problem of a geminated tooth.
Foraging efficiency and adjustment of energy expenditure in a pelagic seabird provisioning its chick
Authors: Weimerskirch Henri , Ancel André , Caloin Michel , Zahariev Alexandre , Spagiari Jérôme , Kersten Marcel , Chastel Olivier 
Published: May 2003

Summary

Foraging determines the intake of resources that are expended on fitness related activities, and allocation links foraging and life‐history traits, but the extent to which individuals are able to adjust energy expenditure according to allocation decisions is still poorly studied.
To examine this, we studied for the first time the efficiency of foraging trips (defined as the ratio of energy gained over energy spent while foraging) in a pelagic seabird provisioning its chick by measuring simultaneously the energy flow to the chick, changes in adult body mass and foraging cost using doubly labelled water. The study was performed over two seasons.
Blue petrels (Halobaena caerulea) alternate between short foraging trips (average 1·9 days, range 1–4 days) where they maximize food delivery to the chick but loose mass, and long foraging trips (7·3 days, 5–10 days) where they increase in mass. They expend 1·5–2·2 times more energy per unit of time during short trips (2561 kJ day−1 kg−1, i.e. 3·2 times the resting metabolic rate) compared to long trips (1142–1676 kJ day−1 kg−1, i.e. 1·4–2·1 the resting metabolic rate).
The currency during long trips is therefore to maximize efficiency, whereas during short trips the currency is to maximize rate of energy delivery to the chick. Maximum efficiency peaks for 6‐day trips, i.e. when adult mass gain is highest, foraging costs are lowest and efficiency was extremely low during short trips. A duration of 6 days is therefore the optimal duration of long foraging trips but trips of 7 days were more common.
Our study shows that self‐feeding during long trips is crucial for the success of short trips because most of the energy used during short trips is probably derived from the energy stored during long trips. Self‐feeding during short trips is probably negligible.
The study indicates that surprisingly long distance foraging may not always result in higher foraging costs compared to shorter movements. It highlights the predominant role of body store usage as a mechanism for this animal to adjust energy expenditure and energetic efficiency during foraging for allocation purposes.
Variation and covariation in survival, dispersal, and population size in barn owls Tyto alba
Authors: Altwegg Res , Roulin Alexandre , Kestenholz Matthias , Jenni Lukas 
Published: May 2003

Summary

Population dynamics are the result of variation in survival, recruitment, emigration and immigration rates. Covariation between these demographic rates critically affects the dynamics and magnitude of fluctuations in population size. Such covariation can arise by environmental factors affecting several rates in similar ways. Also demographic processes, such as the source–sink and the balanced dispersal process, are expected to lead to covariation between demographic rates.
Here, we study variation and covariation in survival, emigration, immigration, and the size of a Swiss barn owl (Tyto alba) population, and examine the factors associated with this variation. For practical reasons, survival and emigration are often confounded in studies of natural populations. We overcome this problem by jointly analysing live‐recapture and dead‐recovery data using recently developed statistical methods.
Mortality, emigration, the number of known immigrants, and population size were positively correlated over time. Neither the source–sink nor the balanced dispersal process is expected to lead to this pattern.
Survival was lower for juveniles than adults (mean 17% vs. 72%), and highly variable across years in both age classes. Snow cover, mean annual temperature and population density accounted for 32–47% of the variation in survival of juveniles and adults. Emigration was higher for juveniles than for adults, and adults emigrated more often when the population size was higher.
Our results showed that local population dynamics were affected by density dependence and the stochastic environmental factors snow cover and temperature. Rather than lending support to one of the two dispersal hypotheses, the patterns of correlation between survival, dispersal, and population size suggest strong fluctuations in environmental conditions that influence the dynamics of barn owl populations at a larger spatial scale.
Dispersal within a spatially structured population of lesser kestrels: the role of spatial isolation and conspecific attraction
Authors: Serrano David , Tella José L. 
Published: May 2003

SummaryFactors governing dispersal rates have seldom been examined in spatially structured populations of vertebrates. We gathered information during 8 years on transfer rates between subpopulations in a spatially structured, growing population of colonial lesser kestrelsFalco naumanni, and analysed the contribution of several variables related to spatial isolation and characteristics of both subpopulation of origin and destination on probabilities of dispersal.Lesser kestrels were highly philopatric to their subpopulations, but first‐breeders dispersed more often than adults (26% vs. 4%,n= 1706) because adults were reluctant to move from familiar areas. Frequency of subpopulation change was higher in females than in males (first‐recruiters: 30% vs. 22%,n= 987; adults 5% vs. 1%,n= 719), according to their different breeding roles. However, all populational factors had an equal effect on individuals of different sex and dispersal status.Movement rates decreased with inter‐subpopulation distance – indicating that travelling to distant subpopulations may impose costs in terms of breeding prospects – and with the number of subpopulations, which increased during our study period.Conspecific attraction strongly influenced the probability of dispersal: it was relatively higher in largely populated subpopulations, and individuals of large subpopulations were reluctant to change to others. These results were neither influenced by the size and breeding density of the subpopulations nor by habitat quality in terms of food availability or risk of predation, as indicated by breeding success of kestrels at each subpopulation. The number of conspecifics could be used by the kestrels as a cue of patch quality in terms of settlement options, and large subpopulations could be more easily detected by prospecting birds.Our study highlights the fact that several assumptions of theoretical metapopulation modelling are often not fulfilled in nature. Both theoretical models and management strategies on spatially structured populations or metapopulations should thus consider the number, population size, and spatial distribution of local populations, as well as their relationships with the dispersal ability of the species.
Host preference and performance of lichenivorous Eilema spp. larvae in relation to lichen secondary metabolites
Authors: Pöykkö Heikki , Hyvärinen Marko 
Published: May 2003

Summary

We compared the larval host preference of four lichenivorous Eilema (Lepidoptera, Arctiidae) species on four common epiphytic lichen species including Hypogymnia physodes, Melanelia exasperata, Vulpicida pinastri and Xanthoria parietina. Survival and growth of larvae on different species were monitored and correlation to qualitative and quantitative variation in lichen secondary compounds was analysed.
All moth species preferred M. exasperata, which does not contain polyphenolic substances, over other lichens, but also foraged on other lichens in the food preference experiment. All larvae reared on V. pinastri and H. physodes died during the growth and survival experiment. Survival of larvae on X. parietina and M. exasperata were equal. Larvae grew faster and and bigger on M. exasperata than on other lichens.
Consumption and utilization measurements also revealed that M. exasperata was of the highest quality, although the relative consumption rate was highest on X. parietina. Our results indicate that different secondary chemicals have different effect against lichenivores or that larvae are either well adapted to certain chemicals or that these chemicals may have other roles than antiherbivore function for lichens.
It is suggested that lichenivorous lepidopteran species may have different adaptations, such as dietary mixing to receive nutrients in optimal proportions or compensatory feeding ability to ensure the maximal growth efficiency on a suboptimal host.
Measuring beta diversity for presence–absence data
Authors: Koleff Patricia , Gaston Kevin J. , Lennon Jack J. 
Published: May 2003

Summary

Little consensus has been reached as to general features of spatial variation in beta diversity, a fundamental component of species diversity. This could reflect a genuine lack of simple gradients in beta diversity, or a lack of agreement as to just what constitutes beta diversity. Unfortunately, a large number of approaches have been applied to the investigation of variation in beta diversity, which potentially makes comparisons of the findings difficult.
We review 24 measures of beta diversity for presence/absence data (the most frequent form of data to which such measures are applied) that have been employed in the literature, express many of them for the first time in common terms, and compare some of their basic properties.
Four groups of measures are distinguished, with a fundamental distinction arising between ‘broad sense’ measures incorporating differences in composition attributable to species richness gradients, and ‘narrow sense’ measures that focus on compositional differences independent of such gradients. On a number of occasions on which the former have been employed in the literature the latter may have been more appropriate, and there are many situations in which consideration of both kinds of measures would be valuable.
We particularly recommend (i) considering beta diversity measures in terms of matching/mismatching components (usually denoted a, b and c) and thereby identifying the contribution of different sources of variation in species composition, and (ii) the use of ternary plots to express the relationship between the values of these measures and of the components, and as a way of understanding patterns in beta diversity.