bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of simulated root canals using the Macfile, Canal Master U and K‐FIexofile
Authors: MARTIN G. , BLAŠKOVIćG‐ŠUBAT V. 
Published: November 2003

SummaryThe efficacy of three different root canal instruments in maintaining the original shape of curved canals was evaluated. Acrylic blocks were prepared to simulatecanals with 40° and 60° curvature. K‐Flexofiles and Macflles were used with a step‐back technique utilizing an ‘in/out’ filing motion. The balanced‐force technique was used with Canal Master ‘U’ instruments. Ten 40° and 10 60° canals were prepared with each instrument.The results were evaluated using superimposed photo‐graphic slides at X20 magnification to show the canals before and after the instrumentation. The width of the prepared canals was measured at their convex/concave point to determine the divergence of the instrumented canal shape from the original canal shape. The measure‐ments were taken at the level of the apical foramen and 3 and 6 mm coronal to it. In this way it was possible to recognize all the defects created during the preparation of a canal. Among the tested instruments, the Macfile provoked minimal canal deviation (P=0.05).The Canal Master ‘U’ was similarly effective (P=0.05), but had the highest incidence of instrument fracture. The K‐Flexofile demonstrated the most defects in canal preparation and canal deviation, particularly at the level of the apical foramen (P< 0.01)
Thermographic assessment of heat generated on the root surface during post space preparation
Authors: HUSSEY D. L. , BIAGIONI P. A. , MCCULLAGH J. J. P. , LAMEY P.‐J. 
Published: November 2003

SummaryThe mechanical preparation of a post space in a root filled tooth is commonly carried out using rotating instruments in a slow handpiece. This procedure creates frictional heat which may be transferred to the root surface. In this investigation, the temperature changes on the root surface of 12 root filled, extracted human premolar teeth during preparation of post spaces were analysed using an infrared thermal imaging camera. A rotational speed of 8000 r.p.m. was used and the teeth were prepared with size 2 and 3 Peeso reamers and a red Parapost drill to the optimal length. The results indicate that very large temperatures are generated on the root surface and that this is greatest during the Parapost preparation stage. The long‐term clinical effects of post space preparation by engine driven drills would warrant further investigation.
Thermographic assessment of root canal obturation using thermomechanical compaction
Authors: MCCULLAGH J. J. P. , BIAGIONI P. A. , LAMEY P.‐J. , HUSSEY D. L. 
Published: November 2003

SummaryThe temperature changes on the root surface of 30 extracted human premolar teeth during thermomechanical root canal obturation with gutta‐percha were determined using an infrared thermal imaging camera. Three handpiece rotational speeds of 8, 12 and 16 × 103 r.p.m. were used, in conjunction with a Gutta Condensor. On completion of the procedure, the quality of tooth canal obturation was examined radiographically. Under the conditions of this experiment, surface root temperature rises of >97° were recorded during all three speed settings. The radiographic quality of obturation between the groups appeared not to be significantly different. The clinical relevance of these findings is uncertain, but the temperatures reported are of a magnitude to be of biological importance.
Short‐term tissue response to potential root‐end filling materials in infected root canals
Authors: CHONG B. S. , PITT FORD T. R. , KARIYAWASAM S. P. 
Published: November 2003

SummaryThe short‐term tissue responses to two potential root‐end filling materials, a light‐cured glass ionomer cement (Vitrebond) and a reinforced zinc oxide–eugenol cement (Kalzinol), were compared with that to amalgam using a previously devised experimental model. In 24 premolar teeth of beagle dogs (47 roots), a collection of endodontic pathogenic bacteria was first inoculated into the root canals to induce periradicular lesions. On each root, an apiccctomy was performed and root‐end cavities prepared to receive fillings of each material. The teeth and surrounding jaw were removed after 2 weeks (23 roots) and 1 week (24 roots); they were then prepared for histological examination. The tissue response to amalgam fillings after 2 weeks and 1 week was marked by moderate or severe inflammation on all roots, and extended to 0.5 mm or >0.5 mm in 15 out of 16 roots. In contrast, after 2 weeks, the majority of roots filled with Kalzinol showed little or moderate inflammation, while the tissue response to Vitrebond was the best of the three materials, and was also the least extensive. After 1 week, the overall best tissue response was with Vitrebond, followed by Kalzinol. The differences between materials for both time periods with either none or few inflammatory cells when compared with that with either moderate or severe inflammation were not statistically significant (P<0.02). However, the differences between materials for both time periods with no inflammation or inflammation extending <0.2 mm when compared with that with inflammation extending >0.2 mm (0.5 mm or >0.5 mm) were statistically significant (P<0.01). Apart from amalgam, in which healing was marked by the persistence of a localized focus of inflammation adjacent to the root‐end filling, even though there were intersamlpe variations, there was little overall difference in the temporal and qualitative healing response to Vitrebond and Kalzinol. Both Vitrebond and Kalzinol have potential as root‐end filling materials, as the tissue response was considerably more favourable than that to amalgam even in the short‐term.
Shaping ability of NT Engine and McXim rotary nickel‐titanium instruments in simulated root canals. Part 1
Authors: THOMPSON S.A. , DUMMER P.M.H. 
Published: November 2003

SummaryThe aim of this study was to determine the shaping ability of NT Engine and McXim nickel‐titanium rotary instruments in simulated root canals. In all, 40 canals consisting of four different shapes in terms of angle and position of curvature were prepared by a combination of NT Engine and McXim instruments using the technique recommended by the manufacturer. Part 1 of this two‐part report describes the efficacy of the instruments in terms of preparation time, instrument failure, canal blockages, loss of canal length and three‐dimensional canal form. Overall, the mean preparation time for all canals was 6.01 min, with canal shape having a significant effect (P<0.01) on the speed of preparation. One instrument fractured and only four instruments deformed, with most of the failures occurring in canals with curves which began 12 mm from the orifice, that is, in short acute curves. None of the canals became blocked with debris. Following preparation, 20 canals retained their original working length but 19 lost length and one gained in length; there were significant differences (P<0.05) between the canal shapes in terms of mean loss of distance and in the category of distance change. Apical stops as determined from intracanal impressions were present in 37 of the canals; 16 were judged to be of good quality and 21 of poor quality. The canals were found to be smooth in the apical half of the canal in 33 specimens and in the coronal half of 39 specimens. All canals had good taper characteristics and 35 had good flow characteristics. Under the conditions of this study, NT Engine and McXim instruments prepared canals rapidly, with few deformations, no canal blockages and with minimal change in working length. The three‐dimensional form of the canals demonstrated good flow and taper characteristics.
The effects of sodium hypochlorite and calcium hydroxide on tissue dissolution and root canal cleanliness
Authors: TüRKüN M. , CENGIZ T. 
Published: November 2003

SummaryIn this in vitro study, we investigated the efficacy of sodium hypochlorite (NaOCl) and calcium hydroxide (Ca(OH)2) in dissolving necrotic tissue and cleaning root canals. In the first part of the study, 0.5% NaOCl solution and Ca(OH)2 paste and solution were tested with samples of necrotic bovine muscle in different treatment modes and for different periods. The necrotic tissue was weighed before and after the test and the percentage of weight change calculated. In the second part of the study, 40 extracted single‐rooted human teeth were hand instrumented and then subjected to different irrigation regimens. The cleansing efficacy in root canals of 0.5% NaOCl with Ca(OH)2 pretreatments and ultrasonics was examined using scanning electron microscopy. A solution of 5% NaOCl was significantly more effective than 0.5 % NaOCl as a solvent of necrotic tissue. Calcium hydroxide was an effective solvent for necrotic tissue as a paste but not as a solution. Pretreatment of necc tissue with Ca(OH)2 increased its solubility in 0.5% NaOCl. While 5% NaOCl plus ultrasonic irrigation produced cleaner root‐canal walls at the middle and apical thirds, 0.5% NaOCl used with the same technique achieved no root‐canal cleaning. However, pretreatment of root canals with Ca(OH)2 paste increased the effectiveness of 0.5% NaOCl plus ultrasonic irrigation, except in the coronal third of the root canal.
A model for the teaching of clinical techniques in root canal treatment
Authors: NATTRESS B. R. , MANOGUE M. , CARMICHAEL F. 
Published: November 2003

SummaryA practical model to aid the understanding and practice of endodontic techniques is described. The model uses extracted teeth mounted in light‐cured acrylic resin and set in a preformed model tray. Before mounting, the root surfaces of teeth are dipped in wax to simulate the periodontal ligament space. This model allows endodontic techniques to be practised in the operative technique classroom in a way that simulates the clinical situation and enables radiographs of good diagnostic quality to be taken during treatment. Subsequently, teeth can be reset to allow restoration of the root‐filled tooth.
Incomplete calcium hydroxide removal from the root canal: a case report
Authors: RlCUCCI D. , LANGELAND K. 
Published: November 2003

SummaryThis case demonstrates failure of root canal treatment of a maxillary central incisor following incomplete mechanical removal of a Ca(OH)2intracanal dressing and subsequent resorption of the material from the apical portion of the root canal. Retrearment some 4 years later involved the removal of the contents of the root canal and permanent obturation by lateral condensation of cold gutta‐percha with a sealer. Follow‐up showed complete periradicular bone healing with a lamina dura evident. An explanation of the processes involved is offered, based upon histopathological and microbiological evidence in the literature.
Comparison of two endodontic handpieces during the preparation of simulated root canals
Authors: SMITH R. B. , EDMUNDS D. H. 
Published: November 2003

SummaryThe objective of this in vitro study was to compare and assess two endodontic handpieces during the preparation of simulated root canals. One hundred and sixty simulated root canals in clear resin blocks, of two angles and positions of curvature, were prepared using either Shaper files activated by the MM1500 Sonic Air handpiece (Micro‐Mega, Besançon, France)or Excalibur files activated by the W & H Excalibur 969 handpiece (W & H, Bürmoos, Austria). Files of 21‐mm or 25‐mm length were used. When preparing the canals, the files were used either in line with or perpendicular to the canal curvature. Preparation of the canals was carried out using a technique described in the manufacturers' literature. A variety of parameters were used to compare the handpieces, including an assessment of the canal preparation time, the deformation or fracture of instruments, loss of canal length, weight loss from the resin blocks and the overall postpreparation canal shape. Both handpieces provided an efficient and easy method of preparing and shaping the root canal with little operator fatigue. The MM1500 Sonic Air handpiece took significantly more time (P < 0.001) to prepare the canals and was associated with both more loss of working length (P < 0.05) and more loss of weight (P < 0.001). Both handpieces created a high percentage of aberrations in the shapes of prepared canals. The MM1500 Sonic Air handpiece created significantly more aberrations than the Excalibur handpiece (P <0.05 for zip and elbow, P < 0.05 for danger zone and coronal narrow). The effects of the variables, canal curvature, file length and the plane of use of the file, on the performance of the handpieces, were also assessed.
Arsenical necrosis of the jaws
Authors: BATAINEH A. B. D. , AL‐OMARI M. A. O. , OWAIS A. I. 
Published: November 2003

SummaryAfter a brief historical review of the use of arsenic in dental practice two cases of arsenical necrosis of the jaws, affecting the maxilla and mandible respectively, are reported. Both patients were treated conservatively over an extended period with excellent results. It is concluded that there is no justification, whatsoever, for the use of arsenic in modern dental practice and that, although prolonged, conservative treatment of chemical necrosis of the jaws is preferable to more radical treatment.
Root canal treatment of a mandibular first molar with three mesial root canals
Authors: HOLTZMANN L. 
Published: November 2003

SummaryThe dynamic concept of the root canal system, describing a variable morphology of multiple root canals interconnected by anastomoses, has been established as the prevailing state in mandibular molars. This case report presents the treatment of a mandibular first molar with five root canals, of which three were located in the mesial root. A third middle root canal was found between the mesiobuccal and mesiolingual root canals. The morphological pattern of separate apical terminations of the three mesial root canals, as manifested in this case, is a very rare one and seldom encountered.
Reliability of different electronic apex locators to detect root perforations in vitro
Authors: KAUFMAN A.Y. , FUSS Z. , KEILA S. , WAXENBERG S. 
Published: November 2003

SummaryThe aim of this study was to evaluate the accuracy of the electronic apex locator Root ZX compared to the Sono Explorer Mark II Junior and Apit III in detecting root perforations. Extracted human teeth (n=30) were perforated artificially in the middle third of the root and embedded in a box containing alginate. Detection of all perforations were carried out with K‐files attached to the apex locators tested. The teeth were radiographed after each electronic measurement. The actual location of the tip of the file in relation to the external root surface and the radiographic determination of the perforations were carried out using a stereomicroscope. The mean distance of the tip of the file from the external outline of the root surface was short for all instruments and clinically acceptable(0.06–0.25 mm). There was no clinically significant difference between the morphometric measurements and the radiographic measurements. No statistical significance was found between large perforations (0.55–0.60 mm) and small perforations (0.25–0.40 mm). Under the conditions of this study, all electronic apex locators tested were acceptable clinical tools in the detection of root perforations.
The behaviour of post‐retained core materials supported by coronal tooth structure in vitro
Authors: RUSSELL M. D. , MASOOD M. , CUNNINGHAM L. 
Published: November 2003

SummaryThis study was designed to investigate the effect of retaining coronal tooth substance on the performance of post‐retained core materials, and to compare the fracture resistance of the system with an intact tooth prepared to similar dimensions. Ten teeth restored with post‐retained silver amalgam, and 10 teeth restored with silver‐glass cermet, all with a retained single wall of coronal tooth substance, were compared with 10 unrestored teeth prepared to similar dimensions when subjected to a shearing load. The results showed no statistically significant difference between the unrestored teeth and those restored with a silver‐glass cermet. Whilst the teeth restored with silver amalgam had a significantly higher fracture resistance (P > 0.01) there was greater tendency to root fracture.
Anin vitro investigation of coronal leakage with three guttapercha backfilling techniques
Authors: McROBERT A. S. , LUMLEY P. J. 
Published: November 2003

SummaryThe aim of this study was to compare the backfilling capabilities of System B, Obtura II and Alphaseal. Fortysix lower premolar teeth were prepared chemomechanically and allocated to four experimental and two control groups. Ten were obturated using lateral condensation as a standard and 30 were obturated in the apical third using the System B. The latter 30 teeth were then backfilled using one of three techniques, System B, Obtura II or Alphaseal (n=10 in each group). The remaining six teeth served as controls. Roots were radiographed from the proximal in order to evaluate voids and then placed in India ink for 65 h prior to being demineralized and rendered transparent, coronal leakage was quantified by linear measurement of ink penetration. No significant difference was found between the four groups with respect to the presence of voids radiographically (P<0.05). The difference in leakage between the System B and Obtura II groups was not significant (P<0.05). Both System B and Obtura II leaked significantly less than Alphaseal and lateral condensation (P0.001).
Effect of tumour necrosis factor‐α (TNF‐α) and interferon‐γ (IFN‐γ) on human sperm motility, viability and motion parameters
Authors: ESTRADA L. S. , CHAMPION H. C. , WANG R. , RAJASEKARAN M. , HELLSTROM W. J. G. , AGGARWAL B. , SIKKA S. C. 
Published: November 2003

Male genital tract infections and non‐specific inflammatory conditions may be associated with unexplained infertility. Previous studies have shown the presence of cytokines such as tumour necrosis factor‐α (TNF‐α) and interferon‐γ (IFN‐γ) in the semen of infertile men. However, the mechanism of effect of these cytokines on human sperm function is still controversial. The present study was undertaken to investigate the in‐vitro effects of TNF‐α and IFN‐γ on human sperm motion, viability and the hypoosmotic swelling test (HOST).Washed spermatozoa from normal volunteers (n=9) were incubated in the presence/absence of TNF‐α (1 μg/mL) plus IFN‐γ (0.1 μg/mL). Sperm motility, viability, HOST, and video sequences were recorded at different time intervals (0, 30, 60 and 180 min). Sperm motion parameters were analysed using computer‐assisted semen analysis. There was a time‐dependent negative effect of TNF‐α plus IFN‐γ on sperm motility, viability, HOST, and lateral‐head displacement (ALH). The maximum decrease was observed between 60 and 180 min for sperm motility (50.8 ± 5.6%), viability (52.8 ± 4.0%), HOST (38 ± 2%) and ALH (4.7 ± 0.1 μm) compared to control samples (62.2 ± 2.8, 62.4 ± 2.9, 58 ± 4, and 5.3 ± 0.4, respectively; All p < 0.05). There was no significant effect on sperm straight‐line velocity and mean linearity when compared to control.These data suggest that the common inflammatory cytokines TNF‐α plus IFN‐γ have only partial detrimental effects on sperm motility, viability, membrane integrity and lateral head displacement, which may contribute to the poor fertilizing potential of human spermatozoa during inflammatory conditions.
Improved preservation of ultrastructural morphology in human spermatozoa using betaine in the primary fixative
Authors: SWAN M. A. 
Published: November 2003

Improved preservation of the ultrastructural morphology of human spermatozoa was obtained by filtration onto a Millipore filter (0.45 μm pore size) followed by fixation for 1 h in a fixative containing 3% glutaraldehyde, 1% formaldehyde and 21 mM betaine in Hepes or cacodylate buffer. Betaine raised fixative osmolality only slightly but markedly improved the ultrastructural appearance of the spermatozoa; it is known to function as an osmoprotectant in other situations, and may protect the cells from osmotic damage during the initial stages of fixation.The method is suitable for oligozoospermic samples as they are concentrated when the seminal plasma passes through the filter. Utilizing fixation after swim‐up, it is suitable also for highly viscous semen.The fixative gave equally good preservation of sperm heads and tails and can be stored prior to use. The Millipore filter did not dissolve until placed in acetone prior to embedding, simplifying the exchange of solutions during processing. Improved preservation of rat epididymal ultrastructure was obtained by addition of betaine to the fixative of Ito & Karnovsky (1968), using immersion fixation.
Atrial natriuretic peptide, brain natriuretic peptide and c‐type natriuretic peptide: effects on testicular microcirculation and immunohistochemical localization
Authors: COLLIN O. , LISSBRANT E. , BERGH A. 
Published: November 2003

The effect of local injection of atrial (ANP), brain (BNP) and C‐type (CNP) natriuretic peptides and an ANP antagonist (HS‐142–1) on testicular microcirculation and vasomotion was studied using laser Doppler flowmetry. The natriuretic peptides were also localized immunohistochemically within the testis.ANP, BNP‐32, CNP‐22 and CNP‐53 all caused a dose‐related increase in testicular blood flow. The effect of ANP was blocked by concomitant injection of the ANP antagonist. Immunoreactive (ir) CNP and ir BNP were found in Leydig cells whereas ir ANP was observed in the seminiferous tubules. It is suggested that the natriuretic peptides could play a role in local regulation of the testicular microcirculation.
Ultrastructure of rat lung following inhalation of ricin aerosol
Authors: BROWN R. F. R. , WHITE D. E. 
Published: November 2003

Ricin is one of a group of structurally related plant lectins and is extracted from the seeds of the Castor Oil plant, Ricinus communis.Groups of rats were exposed to ricin aerosol by inhalation, total LCt1 = 11.21 mg.min.m−3 (an approximate LCt30 exposure) and examined, using transmission electron microscopy, at intervals up to 48 h after exposure.The first signs of change in ultrastructure were seen at between 6 and 12 h post exposure in alveolar macrophages and took the form of apoptotic changes primarily in the nucleus. These included heterochromatin condensation at the nuclear periphery and crenulation of the nuclear membrane. There then followed a sequence of changes in the cells of the alveolar wall and blood/air barrier culminating in intra‐alveolar oedema at 12 and 15 h after exposure.Damage was first observed in the capillary endothelium and type I epithelial cell changes were evident from 12 h post exposure onward. These changes appeared to be necrotic rather than apoptotic in nature and suggest that mechanisms other than a direct effect of ricin may be involved.Associated with these changes were mixed inflammatory cell infiltrates in the interstitium, isolated type II pneumocyte necrosis and evidence of microvascular microthrombosis. By 48 h after exposure, the intra‐alveolar oedema appeared less marked with prominent hyperplasia of type II pneumocytes.The identification that apoptosis of alveolar macrophages plays a significant part in the mechanism of toxicity following exposure to ricin raises the possibility of developing new therapeutic strategies against poisoning by ricin.