bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of storage time on the degree of dye leakage of root‐end filling materials
Authors: HIGA R.K. , TORABINEJAD M. , MCKENDRY D. J. , MCMILLAN P. J. 
Published: September 2007

SummaryThe quality of the apical seal obtained by root‐end filling materials generally has been assessed by the extent of dye penetration. Most investigators have allowed the root‐end filling materials to set before they are tested. The purpose of this study was to evaluate if storage time had any influence on the amount of dye leakage.Seventy extracted single rooted human anterior teeth were used. After removal of their anatomical crowns, the roots were instrumented, filled with gutta‐percha and Roth's sealer, and subjected to test conditions. The roots were coated with two coats of nail polish. Root ends were resected and class I cavities prepared. Sixty class I root‐end cavities were filled with with either amalgam, super EBA, or IRM (20 each). Ten roots in each group were placed immediately into India ink for 48 h, the other 10 were stored for 24 h before placement into the ink. Ten roots (five per group) were used as positive (gutta‐percha, no sealer) and negative (bone wax) controls. The roots were then demineralized, linear dye leakage was measured, and the data were evaluated statistically using ANOVA.Super EBA, and IRM showed significantly less dye leakage than amalgam (P<0.0001). No significant difference existed between Super EBA and IRM. Storage time had no significant influence on the amount of dye leakage observed in this study.
In vitro temperatures produced by a new heated injectable gutta‐percha system
Authors: WELLER R. N. , KOCH K. A. 
Published: September 2007

Summary In vitro intracanal temperatures produced by the injection of high‐temperature thermoplasticized gutta‐percha were measured. Obturations of a standard root canal were performed using an Obtura II heated gutta‐percha system at temperature settings of 160, 185, and 200°C. There was an increase in the recorded temperatures in the root canal for all three temperature settings with the mean temperature range from 38, 52°C to 61.58°C.The mean temperature of the empty heating chamber was also measured and was accurately indicated on the control unit. However, the mean temperature of the gutta‐percha in the heating chamber was almost 20°C cooler than expected at each of the three settings. Finally, there was more than a 100°C decrease in the mean temperature of the extruded gutta‐percha in relation to the temperature of the gutta‐percha in the heating chamber.Several clinically relevant observations were noted. Each of these observations was related to the temperature setting of the Obtura II control unit.
Radicular penetration of hydrogen peroxide during intra‐coronal bleaching with various forms of sodium perborate
Authors: WEIGER R. , KUHN A. , LÖST C. 
Published: September 2007

SummaryThe development of external cervical root resorption following internal bleaching of discoloured pulpless teeth is associated with the use of hydrogen peroxide. The aim of the study was to determine radicular penetration of hydrogen peroxide following intracoronal bleaching with various forms of sodium perborate, 63 extracted human incisors were root filled and stained artificially. Standardized cementum defects were created on the mesial and distal aspects of the root directly below the cemento‐enamel junction (CEJ). Using the walking bleach technique all teeth were bleached for a 6‐day period, with replacement of the bleaching paste after days 1 and 3.Sodium perborate monohydrate (MH), trihydrate (TRH) or tetrahydrate (TH) was mixed with H2O2 or H2O and subsequently placed intracoronatly 1 mm below the labial CEJ. The teeth were divided into six groups:

MH + H2O2(30%)(n=12);
TRH + H2O2(30%)(n=12);
TH + H2O2(30%)(n=12);
TH + H2O(n=12);
TH + H2O gel(n=12);
no bleaching paste (n= 3).

At baseline and at days 1, 3 and 6 the amount of H2O2 taken up from the surrounding medium of each root was indirectly recorded and calculated as p.p.m.Almost all teeth of the experimental groups showed leakage of hydrogen peroxide compared to those of the control group. The radicular penetration of hydrogen peroxide was significantly higher in teeth of groups I and III than in those of groups IV and V (P≤ 0.001). In conclusion, the amount of hydrogen peroxide leakage depends, among other factors, on the form of sodium perborate used. The risk of post‐bleaching cervical root resorption may be diminished by using sodium perborate tetrahydrate in conjunction with H2O.
Ultrasonic root‐end preparation Part 1. SEM analysis
Authors: GUTMANN J. L. , SAUNDERS W. P. , NGUYEN L. , GUO I. Y. , SAUNDERS E. M. 
Published: September 2007

SummaryPreparations of apical cavities in resected root ends using rotary burs, with and without citric acid rinse, and ultrasonic tips were compared based on the presence or absence of superficial debris and smear layer. Three groups of 20 extracted teeth each were prepared as follows; I, a size 010 round bur was used to prepare an apical cavity 2–3 mm down the long axis of the root; II, treatment as per group I followed by a 60‐s rinse with a solution of 10:3 (10% citric acid, 3% Fe2Cl3); and III, an ultrasonic retrotip was used to prepare a 2–3 mm deep apical cavity. Roots were grooved longitudinally, split and prepared for SEM analysis at ×100 and ×780 magnification. Examiners were calibrated to a standardized grading system. Extensive statistical analyses indicated statistically significant differences within and among the groups (P<0.05). Root‐end preparation with a bur created a heavy smear layer at all levels of the preparation. This layer was partially removed during ultrasonic preparation in the apical two‐thirds. A greater removal of the smear layer was achieved with the citric acid rinse (P<0.05). Coronally, root‐end preparations were contaminated with moderate to heavy amounts of debris with all techniques.
Histological healing following surgical endodontics and its implications in case assessment: a case report
Authors: MEYERS J. P. , GUTMANN J. L. 
Published: September 2007

SummaryFollowing extraction of a symptomatic mandibular premolar which had been subjected to two periradicular surgical procedures, significant apical healing was identified histologically. The implications of these findings are discussed in relation to contemporary advocated treatment regimens, case assessment, and interpretation for success and failure.
A comparison of the apical dye penetration patterns shown by methylene blue and India ink in root‐filled teeth
Authors: AHLBERG K. M. F. , ASSAVANOP P. , TAY W. M. 
Published: September 2007

SummaryThis study compared the linear leakage patterns shown by 5% aqueous solution of methylene blue (MB) and India ink (II).One‐hundred and twenty‐five roots with single canals from extracted human teeth were used. The canals were cleaned and shaped using the step‐back technique under copious irrigation. Three groups were arranged to receive root fillings of gutta‐percha and one of three proprietary sealers using standard lateral condensation techniques: Sealapex (40 roots), Tubli‐Seal (40 roots) and Ketac‐Endo (20 roots). The remaining roots were used as controls: positive with gutta‐percha and no sealer and negative with the apices sealed with nail varnish. The roots were randomly selected for 7‐day immersion in either MB or II, then sectioned longitudinally; dye penetration was assessed using a Wild Leitz stereomicroscope.In all groups MB showed more penetration than II. The results were statistically significant at the P= 0.01 level, with the exception of the positive control groups. Negative controls showed no penetration.It is concluded that MB, which has a low molecular weight penetrated more deeply along root canal fillings than II, which has a large particle size.
Leaving the pulp chamber open for drainage has no effect on the complications of root canal therapy.
Authors: TJÄDERHANE L. S. , PAJARI U. H. , AHOLA R. H. , BÄCKMAN T. K. , HIETALA E. L. , LARMAS M. A. 
Published: September 2007

SummaryIn this retrospective study the effects of different kinds of emergency treatments on flare‐ups and other complications were examined. A total of 197 teeth received emergency treatment after diagnosis at the beginning of the root canal therapy; in 103 the pulp chamber was left open for drainage of pus, 35 were treated with dexamethasone sodium phosphate, and 59 with various other medicaments, followed by routine root canal treatment. In all, 404 teeth received root canal treatment without emergency treatment. If symptoms occurred during treatment, flare‐up was said to be present. If a periapical radiolucency was found, long‐term calcium hydroxide treatment was used: no sign of periapical healing radiographically after 6 months was described as a complication. The percentage of teeth with no complications varied from 72.2% (dexamethasone) to 78.9% (other modification) and the results showed no differences between the groups in the teeth with no complications, flare‐ups or other complications. The number of bacteria detected with Gram's staining was higher in the teeth which were left open. In conclusion, leaving the pulp chamber open for drainage had no effect on the incidence of flare‐ups or other complications.
Reliability of reduced air pressure methods used to assess the apical seal
Authors: RODA R. S. , GUTMANN J. L. 
Published: September 2007

SummaryThe reliability of two commonly used methods of sealability testing, dye leakage under normal atmospheric pressure and dye leakage in a partial vacuum, was tested using a repeated studies design. Forty extracted teeth were instrumented and obturated using lateral condensation of gutta‐percha and Sealapex™ sealer. One‐half of the teeth were placed in India ink under normal atmospheric pressure and the other half underwent air evacuation before immersion in the ink. After 24 h the teeth were removed from the ink and rendered transparent for linear leakage analysis. A second study, repeated within the exact parameters of the first, was performed approximately 1 month later. Mann‐Whitney U tests indicated that there was no significant difference (P>0.05) between the air and vacuum groups or within each group (air or vacuum) between trials, indicating that the methodology is repeatable and that application of reduced air pressure did not enhance reliability. A large majority of the teeth placed under partial vacuum showed evidence of vacuum‐induced artefacts that may negate the value of vacuum as a research tool.
The effect of an Nd–YAG pulsed laser on the cleaning of the root canal and the formation of a fused apical plug
Authors: SAUNDERS W. P. , WHITTERS C. J. , STRANG R. , MOSELEY H. , PAYNE A. P. , McGADEY J. 
Published: September 2007

SummaryA Neodyminium‐yttrium aluminium garnet (Nd–YAG) pulsed laser was used in vitro to determine whether various laser energy levels from 0.75 W to 1.7 W at 15 pulses s−1 (pps) were able to (i) remove debris from the walls of prepared root canals (ii) remove pulpal tissue from unprepared canals and (iii) create a fused apical plug from dentine chips, hydroxyapatite (HAP) or low‐fusing dental porcelain. Single‐rooted teeth were sectioned at the amelocemental junction and the crowns discarded. The root canals of 50 teeth were prepared chemomechanically and allocated to four groups of 10 teeth for laser treatment. One group was left unlased as a control. After lasing, the teeth were split longitudinally, stained and examined for residual debris. Results showed that there was no statistically significant difference between the groups (P < 0.05). A further 20 teeth were not prepared and lased in the coronal one‐third of the root canal at different energy levels; five teeth were not lased. The teeth were split and examined as previously. The results showed that lasing cleaned the coronal part of the root canal almost completely of pulpal tissue. In the final part of the study laser energy was applied to dentine chips, HAP and low‐fusing procelain in an attempt to produce a fused apical plug. The laser was unable to melt the dentine chips but some hardening of HAP occurred when combined with blue food‐colouring, with or without glycerine, at energy levels of 1.0 W, at 15 pps for 30 s. Superficial hardening of low‐fusing porcelain occurred at 1.0 W, 15 pps for 30 s which increased when 1.5 W was applied at 15 pps for 30s.
Ultrasonic preparation and obturation of root‐end cavities
Authors: SULTAN M. , FORD T. R. PITT 
Published: September 2007

SummaryThis study evaluated the preparation of root‐end cavities using an ultrasonically activated file, and the obturation of such cavities. In the first part, the root canals of 40 extracted teeth were prepared to size 40 and irrigated with NaOCl and EDTA. The root ends were resected and the teeth inoculated with Enterococcus faecalis, incubated for 10 days and divided into four groups: control; saline irrigation; hand instrumentation performed via a retrograde approach up to size 50 using saline irrigant; ultrasonic instrumentation with prebent size 40 K‐flex file inserted into a Piezon Master using saline irrigant. The teeth were fixed, sectioned longitudinally and viewed under scanning electron microscopy. Bacterial and smear layer scores were obtained at 1, 3, and 5 mm from the resected end. The bacterial scores for control and saline groups were similar; the scores for each instrumentation group were significantly lower than the control group (P<0.001), In addition, there were significantly fewer bacteria in the ultrasonic group compared with the hand instrument group (P<0.001), The smear layer scores for control and saline groups were similar, and significantly lower than in either instrumentation group (P<0.001). In the second part, root‐end cavities were ultrasonically prepared in 20 extracted teeth. Ten cavities were filled with amalgam, and 10 with thermoplasticized gutta‐percha and Grossman s sealer. After 24‐h storage, the root ends were immersed in dye for 48 h. Cross‐sectional slices of the obturated part of the root were evaluated using both light and confocal microscopy for dye leakage along the interface of filling material and dentine. There were no statistical differences between the leakage of amalgam and gutta‐percha root‐end fillings, nor between the two methods of microscopy.
Studies into the microbial spectrum of apical periodontitis
Authors: BRAUNER A. W. , CONRADS G. 
Published: September 2007

SummaryThis study examined the variety of obligate and facultative anaerobic bacterial species recovered from cases of acute apical periodontitis. A total of 19 root canal samples and 24 periapical granuloma samples were taken from patients suffering pain and discomfort. Bacteria were identified by applying the following techniques: culturing on various media, Gram‐staining and using commercially available biochemical test strips. In addition, Prevotella intermedia and Porphyromonas endodontalis were differentiated on a molecular genetic level using species‐specific oligodeoxymicleotide probes. The most frequently identified bacteria were Prevotella intermedia, Bifidobacterium spp., Streptococcus sanguis. Streptococcus milleri‐group and Bacteroides spp. Obligate anaerobes occured at a rate of 82.3%, and the average number of isolates was 6.4 per sample.
Effect of various zinc oxide materials as root‐end fillings on healing after replantation
Authors: FORD T. R. PITT , ANDREASEN J. O. , DORN S.O. , KARIYAWASAM S. P. 
Published: September 2007

SummaryThis study examined the effect of various zinc oxide materials as root‐end fillings of teeth in a replantation model. A total of 35 molar teeth were used from 19 monkeys. After extraction, root ends were resected, the canals contaminated with oral bacteria, root‐end cavities prepared and fillings placed prior to replantation. After 8 weeks the teeth and surrounding jaw were removed and prepared for histological examination. Twelve roots were filled with IRM plus dentine chips, and six with Cavit; the tissue response around root ends filled with these materials as assessed by inflammation was similar to that previously reported to IRM and Super EBA cement and was characterized by little or no inflammation of limited extent. In contrast, more severe inflammation was observed around root ends filled with plain zinc oxide–eugenol or Kalzinol; however, the reaction was neither as severe nor as extensive as that to amalgam root–end fillings. Giant cells were observed most often on the surface of fillings with Cavit and zinc oxide–1eugenol. It is concluded that the tissue response to IRM with or without added dentine, Super EBA and Cavit was similar and mild; it was less severe than that to zinc oxide‐eugenol and Kalzinol. All these materials had a much more favourable response than amalgam.
In vitro study of the indirect action of calcium hydroxide on the anaerobic flora of the root canal
Authors: KONTAKIOTIS E. , NAKOU M. , GEORGOPOULOU M. 
Published: September 2007

SummaryThe aim of this study was to evaluate in vitro a possible mechanism involved in the antimicrobial action of calcium hydroxide, namely absorption of carbon dioxide from the roof canal.Twenty obligate and 20 facultative anaerobic bacteria isolated from infected root canals and identified to species level were used. For each bacterial species a standard concentration was achieved and 0.1 ml of the inoculum was spread on blood agar plates, which were consecutively incubated in an anaerobic chamber for 5–7 days.One experimental and one control group were studied: the experimental group included one plate with the bacterial species as well as one open plate containing 32 g calcium hydroxide paste at a mixing ratio of 6:4. Both plates were incubated in an anaerobic chamber for 72 h. The control group included only one plate containing the same bacterial species and was incubated under the same conditions. After a 72‐h incubation, the number of the recovered bacteria were counted in both groups.Statistical analysis showed that the number of bacteria recovered from the control group was significantly lower than that of the experimental group, but no particular resistance of any bacterial species to calcium hydroxide could be detected. This finding strongly suggests that the ability of calcium hydroxide to absorb carbon dioxide may contribute to its antibacterial activity.
Sickle cell disease: a diagnostic dilemma
Authors: BISHOP K. , BRIGGS P. , KELLEHER M. 
Published: September 2007

SummaryThe case history is described of a patient with sickle cell anaemia who developed a unilateral infarct of the mandible following a sickle cell crisis. The interruption of the blood supply resulted in an anaesthesia of the inferior dental nerve and pulpal necrosis of otherwise sound premolar and molar teeth. The diagnostic and management difficulties of the case are discussed, and recommendations are made for the treatment of such patients in light of the problems encountered.
Dens invaginatus in a mandibular lateral incisor
Authors: KHABBAZ M. G. , KONSTANTAKI M. N. , SYKARAS S. N. 
Published: September 2007

SummaryA rare case of dens invaginatus involving a non‐carious mandibular lateral incisor with periapical periodontitis is reported. Invaginated teeth present technical difficulties in their clinical management because of their abnormal anatomy. In the present case, non‐surgical root canal therapy was chosen. A one‐year follow‐up clinical and radiographic examination showed a non‐symptomatic tooth with osseous healing proceeding.
Periradicular healing in response to Diaket root‐end filling material with and without tricalcium phosphate
Authors: WILLIAMS S. SNYDER , GUTMANN J. L. 
Published: September 2007

SummaryThe healing of the periradicular tissues was evaluated when the polyvinyl resin Diaket with and without tricalcium phosphate was used as surgical root‐end filling material. Non‐surgical root canal treatment was performed on 56 mandibular premolar roots in mongrel dogs. Following root‐end resection, root‐end cavity preparations were filled with Diaket, the comparative material, or Diaket in combination with tricalcium phosphate, the experimental material. Postsurgically, healing of the tissues adjacent to the filling materials and in the surrounding surgical site were evaluated at 30 and 60 days. There was virtually no statistically significant difference between the experimental and comparative group at or within the 30‐ or 60‐day period with regard to inflammation, connective tissue formation, root‐end encapsulation, cementum formation, or bone apposition. Findings suggest that cementogenesis occurred over both materials. The overall healing of the periradicular tissues was favourable.
Clinical uses of rectified turpentine oil
Authors: KAPLOWITZ G. J. 
Published: September 2007

SummaryRectified turpentine oil can be used to soften or dissolve gutta‐percha in the root canal space to facilitate endodontic retreatment or preparation of space for a post. For endodontic retreatment, the turpentine oil can be heated to 71°C which significantly increases its ability to dissolve gutta‐percha. For removing only a portion of the gutta‐percha while leaving the rest intact, as for the preparation of space for a post, the turpentine oil is delivered to the canal at body temperature (37°C).
Sterilization of infected root‐canal dentine by topical application of a mixture of ciprofloxacin, metronidazole and minocycline in situ
Authors: SATO I. , ANDO‐KURIHARA N. , KOTA K. , IWAKU M. , HOSHINO E. 
Published: September 2007

SummaryThe aim of this study was to observe the potential of a mixture of ciprofloxacin, metronidazole and minocycline to kill bacteria in the deep layers of root canal dentine in situ. After the crowns of extracted teeth had been removed, the drug combination (0.5 mg of each drug), or sterile saline, as the control, was placed in the root canals which had been previously irrigated ultra‐sonically with 0.4 m EDTA. The penetration and bactericidal efficacy were estimated by various procedures as follows. (1) A cell suspension of E. coli was placed into small cavities prepared parallel to the root canals on the cut planes of nine single‐rooted teeth. The teeth were then entirely covered with blue inlay wax. At time 0, and at 5h, 24h and 48h after the drug combination had been applied, cells of E. coli were recovered from the cavities by washing the cavities several times with sterile saline solution, and were cultured on the surfaces of heart‐infusion (HI) agar plates. Total colony‐forming units were then counted. Bacterial recoveries decreased with time, and no bacteria were recovered 48 h after application of the drug combination, while bacteria survived in all cases with the controls. (2) After the drug combination or sterile saline had been placed into and sealed in the root canal with blue inlay wax, the teeth were placed into HI agar plates where cells of E. coli had been inoculated. After culturing, a clear zone caused by the inhibition of bacterial growth was observed around the teeth, but not in the control experiment. (3) After sampling infected root dentine of 12 freshly extracted teeth as positive controls, the drug combination (0.5 mg each) was placed in the root canals. No bacteria were recovered from the infected dentine of the root canal wall 24 h after application of the drug combination, except in one case in which a few bacteria were recovered. On the basis of these results, penetration through dentine and antibacterial efficacy of the drug combination can be expected against bacteria infecting the dentine of the root canal wall in situ when the drugs were placed in root canals which had been irrigated ultrasonically.