bluuebunny/crossref_metadata_2025_split huggingface dataset:
Canal configuration of the mesiobuccal root of the maxillary first molar of a Japanese sub‐population
Authors: Weine F. S. , Hayami S. , Hata G. , Toda T. 
Published: March 2003

Aim The aim of this study was to determine the percentage of anatomical canal configurations of the mesiobuccal root of the maxillary first molar in Japanese patients.Methodology Three hundred teeth were obtained from general dentists who knew absolutely that they were extracted from Japanese patients. The distobuccal and palatal roots were amputated for radiographic convenience. Preoperative radiographs were taken of the remaining crown and mesiobuccal root (MBR) from mesio‐distal and bucco‐palatal directions for each tooth. Routine endodontic access cavities were prepared and size 08 files were placed through the orifice into the MBR until they were seen at the apex. In some cases preparation of the canal orifice with a long shank round burr was necessary to gain access. In seven teeth, no access to the apex was possible and these teeth were eliminated. In the other 293 teeth, the MBR canal(s) was (were) enlarged up to size 15 file. If another canal opening was found at the apex a 08 file was inserted into the second opening and passed coronally. Postoperative radiographs with file(s) in place were taken from the two directions, as before.Results Of the 293 teeth, 123 (42.0%) were Type II, 89 (30.4%) showed Type III systems and 10 (3.4%) were Type IV. Suggestions for identification and treatment of the second canal in the MBR are presented.Conclusions The proportion of cases with two canals in the mesiobuccal root of maxillary first molars from Japanese patients was high and similar to that described from studies of other ethnic populations.
Inducible nitric oxide synthase activity by interferon‐g‐producing cells in human radicular cysts
Authors: Takeichi O. , Hayashi M. , Tsurumachi T. , Tomita T. , Ogihara H. , Ogiso B. , Saito T. 
Published: March 2003

Aim In this study, the interaction of interferon‐γ‐ (IFN‐γ) and inducible nitric oxide synthase (iNOS)‐producing cells in human radicular cysts were investigated.Methodology Inflamed periapical tissues were obtained from patients at the time of endodontic surgical treatments and were cut into two pieces. After fixing with acetone or 4% paraformaldehyde in phosphate‐buffered saline, 5‐m‐thick paraffin and cryostat sections were prepared. The paraffin sections of the inflamed tissues were evaluated histologically with haematoxylineosin stains. The specimens diagnosed as radicular cysts were then examined by immunostaining. Immunohistochemistry for iNOS and fluoresence microscopy for IFN‐γ using the cryostat sections were performed with a mixture of affinity purified human iNOS antiserum and human IFN‐γ monoclonal antibodies.Results The results revealed that iNOS‐γ producing cells localized adjacent to IFN‐γ‐producing cells. In addition, some of iNOS‐producing cells exhibited immunoreactive IFN‐γ. On the other hand, epithelial cells showed significant levels of iNOS production, but not IFN‐γ.Conclusions The data would suggest the possibility that iNOS production could be precisely controlled by autocrine or paracrine effects of IFN‐γ producing cells in radicular cysts and might play a pivotal role in periapical lesions. These findings are consistent with a hypothesis suggesting that NO inhibitors could be used through the root canals as a pharmacological treatment for periapical lesions.
Black‐pigmented anaerobic rods in closed periapical lesions
Authors: Bogen G. , Slots J. 
Published: March 2003

Aim This study determined the frequency of Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia and Prevotella nigrescens in 20 closed periapical lesions associated with symptomatic and asymptomatic refractory endodontic disease.Methodology To deliniate possible oral sources of P. endodontalis, the presence of the organism was assessed in selected subgingival sites and saliva in the same study patients. Periapical samples were obtained by paper points during surgical endodontic procedures using methods designed to minimize contamination by non‐endodontic microorganisms. Subgingival plaque samples were obtained by paper points from three periodontal pockets and from the pocket of the toothassociated with the closed periapical lesion. Unstimulated saliva was collected from the surface of the soft palate. Bacterial identification was performed using a species‐specific polymerase chain reaction (PCR) detection method.Results P. endodontalis was not identified in any periapical lesion, even though subgingival samples from eight patients (40%) revealed the P. endodontalis‐specific amplicon. P. gingivalis occurred in one periapical lesion that was associated with moderate pain. P. nigrescens, P. endodontalis and P. intermedia were not detected in any periapical lesion studied.Conclusions Black‐pigmented anaerobic rods appear to be infrequent inhabitants of the closed periapical lesion.
The shear bond strength of glass ionomer cement sealers to bovine dentine conditioned with common endodontic irrigants
Authors: Lalh M. S. , Titley K. , Torneck C. D. , Friedman S. 
Published: March 2003

Lahl MS, Titley K, Torneck CD, Friedman S. The shear bond strength of glass ionomer cement sealers to bovine dentine conditioned with common endodontic irrigants. International Endodontic Journal, 32, 430–435 1999.Aim The aim of this in vitro study was to evaluate the shear bond strength of commercially available and experimental glass ionomer cement (GIC) sealers to dentine exposed to common endodontic irrigants.Methodology The enamel of 90 bovine incisor crowns, randomly divided into nine equal groups, was ground to expose the superficial dentine layer. The exposed surface was conditioned with either: (i) distilled H2O; (ii) 2.6% NaOCl; or (iii) 17% EDTA followed by 2.6% NaOCl. Five cc of each irrigant was applied over a 30‐second period. The following GIC sealers were tested: (i) Ketac‐Endo; (ii) KT‐308, an experimental sealer; and (iii) ZUT, a combination of KT‐308 and an antibacterial agent (0.2% by weight). The test sealers were applied to form cylinders with a standardized contact surface area (17.8mm2) on the conditioned dentine surfaces. Specimens were bench set for 90min and stored in distilled water at 37°°C for 48h, then tested to failure for shear bond strength (MPa) in an Instron machine.Results KT‐308 and ZUT had significantly higher MPa values than Ketac‐Endo (two‐factor ANOVA, P 0.0001), regardless of the dentine conditioning. All specimens conditioned with 17% EDTA and 2.6% NaOCl combined had significantly lower MPa values than those conditioned with water or 2.6% NaOCl alone (P 0.02).Conclusions It was concluded that the experimental sealers KT‐308 and ZUT bonded better to bovine dentine than Ketac‐Endo, and that the bond of all three GIC sealers was better with the smear layer present.
A comparison of two nickel–titanium instrumentation techniques in teeth using microcomputed tomography
Authors: Rhodes J. S. , Ford T. R. Pitt , Lynch J. A. , Liepins P. J. , Curtis R. V. 
Published: March 2003

Aim  The aim of the study was to compare the shaping of root canals by two nickel–titanium instrumentation techniques using microcomputed tomography (MCT).Methodology  Ten mandibular first molar teeth (30 canals) that had intact crowns and fully formed roots were scanned using MCT. Fifteen canals were instrumented using NiTiFlex hand files (Maillefer) using balanced force. The remainder were instrumented using prototype ProFile 0.04 Taper instruments (Dentsply) in a crown‐down manner to an apical size ISO 25. The teeth were scanned again following instrumentation. The two instrumentation techniques were compared in a total of 27 canals. The area of dentine removed at pre‐determined levels (2.0, 3.0, 4.5, 6.0, 7.5 mm) from the apex was measured. Transportation and centring were recorded. Images constructed at these levels were compared with video images of equivalent physical sections created after the second scan. The volume of dentine removed in the apical 7.5 mm of the root canals of each tooth was calculated and the different techniques compared. Rendered three‐dimensional images were used to assess the preparations qualitatively. The time taken for preparation was recorded.Results  There was no significant difference between hand instrumentation with NitiFlex files and machine instrumentation with prototype ProFile 0.04 Taper instruments for any of the variables tested.Conclusions  Both techniques produced well centred and tapered preparations.
Computerized infrared thermographic imaging and pulpal blood flow: Part 2. Rewarming of healthy human teeth following a controlled cold stimulus
Authors: Kells B. E. , Kennedy J. G. , Biagioni P. A. , Lamey P. J. 
Published: March 2003

AbstractAimTo investigate the rewarming pattern and rewarming rate of clinically healthy teeth following a controlled cold stimulus using TI techniques.MethodologyA controlled cold stimulus was developed using an air stream at 20 °C. Gingival and incisal sites on 12 healthy maxillary lateral incisors in six patients were imaged under rubber dam following 20 s cooling. Images were captured at 10 s intervals during a 3‐min rewarming period and the data used to construct graphs of the rewarming rate. Log transformation of the data was used to produce ‘best fit’ straight line graphs. Linear regression analysis was used to examine three variables, viz. the side of the mouth (right or left), the site of measurement (gingival or incisal) and the phase of rewarming (early 0–90 s, late 91–180 s).ResultsThe mean temperature change (Δt °C) during rewarming was 8.5 °C (SD 1.0 °C) for gingival sites and 7.2 °C (SD 1.1 °C) for incisal sites. The slope of the ‘best fit’ straight line data enabled a rewarming index to be calculated for each site on each tooth. Linear regression analysis showed that the phase of rewarming was highly significant but the other variables were not. A one‐way anova showed no significant differences between or within groups.ConclusionsThree min is an appropriate time to record rewarming of teeth cooled for 20 s with an airstream at 20 °C. The side or site used to record surface temperatures using this technique is not significant. Rewarming is exponential and log transformation of the data produces a well‐fitting straight line graph. The slope of this line provides a rewarming index which should enable comparison of TI and laser Doppler flowmetry in determining pulpal blood flow as a measure of tooth vitality.
Computerized infrared thermographic imaging and pulpal blood flow: Part 1. A protocol for thermal imaging of human teeth
Authors: Kells B. E. , Kennedy J. G. , Biagioni P. A. , Lamey P. J. 
Published: March 2003

AbstractAimTo observe the thermographic appearance of teeth and to develop a suitable protocol for imaging teeth in human subjects using modern thermographic imaging (TI) equipment in a thermologically controlled environment.MethodologyThe emissivity of enamel was investigated using an extracted incisor tooth. A total of 12 unrestored maxillary lateral incisors in six healthy patients were then imaged under rubber dam after a 20‐min equilibration period and the thermographic data analysed using a dedicated software package. Recordings were made from standardized gingival and incisal sites on each tooth and the temperature gradient established for each tooth. Subsequently, a sequence of images of both maxillary central incisors in one patient was stored every 30 s during a 20‐min equilibration period with and without an air‐conditioning unit in operation.ResultsFor the lateral incisors there was a consistent temperature gradient (mean 1.28 °C) from gingival area to incisal area and there were no statistically significant differences between right and left sides for the gingival site (t = 0.34, NS) or the incisal site (t = 0.62, NS). The air‐conditioning unit had a rapid and profound cooling effect. With the air‐conditioning disabled there was a mean tooth surface temperature increase of 1.1 °C from 0 to 5 min of the equilibration period and 0.3 °C from 15 to 20 min.ConclusionsThere was no significant difference in gingival or incisal temperatures between pairs of contralateral maxillary lateral incisors and a consistent temperature gradient existed from gingival to incisal areas of healthy maxillary lateral incisor teeth. The protocol described is suitable for TI of vital teeth. However, TI measured tooth surface temperature only which was extremely sensitive to air currents. A 15‐min acclimatization period under rubber dam was adequate to allow stable tooth surface temperature measurement.
Shaping ability of Hero 642 rotary nickel–titanium instruments in simulated root canals: Part 2
Authors: Thompson S. A. , Dummer P. M. H. 
Published: March 2003

AbstractAimTo determine the shaping ability of Hero 642 nickel–titanium rotary instruments during the preparation of simulated canals.MethodologyA total of 40 simulated root canals made up of four different shapes, in terms of angle and position of curvature, were prepared by Hero 642 instruments using a crown‐down preparation sequence. Pre‐ and postoperative images of the canals were taken using a video camera attached to a computer with image analysis software. The pre‐ and postoperative views were superimposed to highlight the amount and position of material removed during preparation. This report describes the efficacy of the instruments in terms of prevalence of canal aberrations, the amount and direction of canal transportation and overall postoperative shape.ResultsFour zips and four elbows were created during preparation, all in canals with 40°, 12 mm curves. No perforations or danger zones were created. Highly significant differences (P < 0.001) were apparent between the canal shapes in total canal width at the apex and beginning of the curve, and in the amount of resin removed from the inner and outer aspects of the curve at the orifice. Canal transportation was most frequently directed toward the outer aspect of the curve at specific points along the canal, except at the orifice, where it was apparent that canals with 20° curves transported toward the inner. Overall, mean absolute transportation was always less than 0.15 mm; however, significant differences occurred between canal shapes at the end‐point (P < 0.01), apex of the curve (P < 0.01) and at the orifice (P < 0.01).ConclusionsUnder the conditions of this study, Hero 642 rotary nickel–titanium instruments created canals with few aberrations and no perforations. The relatively high proportion of aberrations in canals with short, acute curves may indicate that instruments with increased taper should be used with caution at or near the full working distance. Further research in real teeth is necessary to elucidate the full potential of these new rotary instruments for use in root canal preparation.
Complications during root canal irrigation – literature review and case reports
Authors: Hülsmann M. , Hahn W. 
Published: March 2003

AbstractLiterature review and case reportsThe literature concerning the aetiology, symptomatology and therapy of complications during root canal irrigation is reviewed. Three cases of inadvertent injection of sodium hypochlorite and hydrogen peroxide beyond the root apex are presented. Clinical symptoms are discussed, as well as preventive and therapeutic considerations.
Mandibular first molar with three distal root canals
Authors: Kimura Y. , Matsumoto K. 
Published: March 2003

AbstractCase reportA right mandibular first molar requiring root canal treatment was found to have one mesial and two distal roots and a total of five canals. The mesial and distobuccal root had two separate canals; the distolingual root had one. This case demonstrates a rare anatomical configuration and supplements previous reports of the existence of such configurations in mandibular first molars.
Pulpal response to prolonged dentinal exposure to sodium hypochlorite
Authors: Tang H.‐M. , Nordbö H. , Bakland L. K. 
Published: March 2003

AbstractAimThe aim of this study was to examine the effect of undiluted NaOCl on vital pulp tissue when applied to freshly cut dentine.MethodologyClass V cavities were prepared to a depth of 2 mm in 20 teeth in four Beagle dogs. The cavities on one side of each dog were irrigated continuously for 5 min with 5.25% NaOCl, whilst the cavities on the opposite side in each dog were irrigated with saline for the same length of time. Prior to filling each cavity with Cavit, they were again rinsed with saline and gently dried with an air stream. The dogs were sacrificed to allow for investigation of pulpal conditions under the cavities after periods of 24 h, 1 week, and 4 weeks. Histological preparations were made and stained with H & E for evaluation of the pulp subjacent to each cavity. The tissues were examined for presence of inflammatory cells and categorized as (i) no inflammation, (ii) mild, (iii) moderate, and (iv) severe inflammation.ResultsThe six teeth in the 24 h observation group all showed mild inflammation, both in the NaOCl and the saline groups. After 1 week and 4 weeks, the pulps from all the teeth were free of inflammatory cells.ConclusionUnder the conditions of this experiment, the use of NaOCl in a freshly cut cavity in an intact tooth of a dog, with exposed dentinal tubules, does not appear to cause additional pulpal damage to that caused by the physical contact in cutting tooth structure.
Cyclic fatigue of ProFile rotary instruments after prolonged clinical use
Authors: Gambarini G. 
Published: March 2003

AbstractAimThe purpose of the present study was to evaluate resistance to cyclic fatigue of new and used ProFile Ni–Ti rotary instruments.MethodologyUsed instruments were operated in 10 clinical cases using passive instrumentation and a crown‐down preparation technique. Cyclic fatigue testing of new and used engine‐driven instruments was then performed with a specific device which allowed the instruments to rotate freely inside a stainless steel artificial canal, whilst maintaining conditions close to the clinical situation. Instruments were rotated until fracture occurred and time to fracture was visually recorded with a chronometer.ResultsA significant reduction of rotation time to breakage (life span) was noted between new and used instruments. In all sizes new instruments were significantly more resistant than used ones (two‐sample t‐test, P < 0.01). No instrument underwent intracanal failure during clinical use.ConclusionsProlonged clinical use of Ni–Ti engine‐driven instruments significantly reduced their cyclic fatigue resistance. Nevertheless, each rotary instrument was successfully operated in up to 10 clinical cases without any intracanal failure.
An in vitro study comparing root‐end cavities prepared by diamond‐coated and stainless steel ultrasonic retrotips
Authors: Peters C. I. , Peters O. A. , Barbakow F. 
Published: March 2003

AbstractAimThis study compared the appearance of root‐end cavity preparations and the time required to prepare them using prototype ultrasonic diamond‐coated (DC) and stainless‐steel (SS) retrotips.MethodologyIn 12 maxillary and 12 mandibular molar teeth 48 root‐end cavities were prepared ultrasonically in the palatal, mesio‐buccal, distal and mesial root‐ends using DC and SS retrotips, alternately. Replicas of the resected root tips and the root‐end cavities were examined under a scanning electron microscope (SEM), recording (i) incidence and extent of dentine cracks (ii) minimum remaining thickness of the dentine walls and (iii) surface quality of the resected root‐ends. The time taken to complete the preparation was also recorded. Means of these parameters were compared for both types of retrotips using nonparametric tests.ResultsNo resected root‐ends had cracks before preparation. However, after preparation one root‐end cavity shaped by an SS retrotip had a microcrack visible at 23× magnification. Four and seven other root‐ends had crazed surfaces in the DC and SS groups, respectively (P > 0.05). Remaining minimum dentine thickness was 0.56 ± 0.28 mm and 0.71 ± 0.24 for the DC and SS groups, respectively, and this difference was significant (P < 0.05). A root‐end cavity in one specimen in the DC group was perforated. Preparation times ranged from 25 s to 361 s and were significantly lower for DC tips (P < 0.01) than the SS tips. The time required to prepare root‐end cavities also differed between roots; root‐end preparation in mandibular molars was more time consuming.Conclusions A better quality surface was produced by the prototype diamond‐coated retrotips, in less time than the SS retrotips, which in turn caused fewer cracks than previously reported. DC retrotips removed more dentine than SS retrotips and should therefore be used with care to avoid overpreparation or perforation.
The histological effects of four endodontic sealers implanted in the oral mucosa: submucous injection versus implant in polyethylene tubes
Authors: Figueiredo J. A. P. , Pesce H. F. , Gioso M. A. , Figueiredo M. A. Z. 
Published: March 2003

AbstractAimThe aim of this study was to evaluate pigmentation and tissue response to four endodontic sealers placed in the oral mucosa of rabbits by either submucous injection or implant in polyethylene tubes.MethodologyThirty white New Zealand rabbits were divided randomly into two groups of eight for N‐Rickert and AH‐26, and two groups of seven for Fillcanal and Sealer 26. On the right side of the filter, corresponding to the gingivo‐labial sulcus in humans, the sealer was injected; on the left side the sealer was placed within a polyethylene tube and implanted. Direct clinical observations were made at 30, 60 and 90 days. The animals were then sacrificed for histological analysis.ResultsAfter 60 days of observation N‐Rickert and AH‐26 produced tattoos that became larger by 90 days. Submucous injection produced larger and more numerous pigmentation, when compared to implant in polyethylene tubes. N‐Rickert sealer displayed larger and more numerous tattoos when compared to AH‐26. Histological analysis showed no differences between the two methods of implantation. All sealers elicited some kind of inflammatory response; the most irritant was Fillcanal, followed by N‐Rickert and AH‐26. Sealer 26 elicited a mild reaction only.ConclusionsUnder the conditions of this study there was no relationship between the method of implantation and the tissue response; the silver‐containing sealers produced pigmentation, and the concentration of silver influenced the quantity and size of the tattoos. The sealers elicited various responses when in direct contact with the surrounding tissues; the calcium hydroxide‐containing sealer had enhanced healing when compared to the other sealers.