bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endodontic leakage studies reconsidered. Part I. Methodology, application and relevance
Authors: WU M. ‐K. , WESSELINK P. R. 
Published: September 2007

SummaryAn increasing number of endodontic leakage studies have been published. In the 1990 volumes of Journal of Endodontics and International Endodontic Journal, there was one leakage study to every 4.3 scientific articles. The most popular method was linear measurement of tracer (dye or radioisotope) penetration along a root filling. Comparing some data on linear measurement of dye penetration following the cold lateral condensation of gutta‐percha that were published between 1980 and 1990, a high level of variation has been found, although the experimental methods used in these studies were quite similar. In almost all studies evaluating various techniques, the cold lateral condensation technique has been used as a standard control for comparison. The reliability of these results is questionable. The problems with such studies are discussed. It seems that more research should be done on leakage study methodology, instead of continuing to evaluate the sealing ability of different materials and techniques by methods that may give little relevant information.
Endodontic leakage studies reconsidered. Part II. Statistical aspects
Authors: SCHUURS A. H. B. , WU M. ‐K. , WESSELINK P. R. , DUIVENVOORDEN H. J. 
Published: September 2007

SummaryThe aim of many endodontic studies is to compare two or more treatment methods, techniques or materials, for example, to detect differences in mean leakage scores. As it is not feasible to study large populations, samples are taken. The important question then arises as to how large the sample sizes have to be in order to establish the‘true’(= populations') mean scores. First, it must be determined which magnitude of the difference (= v) between the mean scores is of endodontic interest. Based upon v and a few related statistical parameters, one may calculate how large the samples must be in order that a statistical test yields a significant result for a difference that is of endodontic importance. In other words, the‘power’of a test, depending on the sample size among other factors, must be large enough to detect the‘true’a priori determined difference between the populations. The use of small sample sizes may imply that a rather large difference between two mean leakage scores is not found to be significant, thereby leading to incorrect conclusions. This article describes the power and the statisti‐cal related factors that determine the adequate size of samples. Examples of power calculation are presented. Next, the power of publicized endodontic leakage studies was evaluated. Almost two‐thirds of the sample sizes were 10 or less, and about 90% were 20 or less. Less than one‐half of the tests had an adequate power (conventionally ≤ 0.80). It is necessary to be cautious when extrapo‐lating the results of such studies, because of the limited power of the statistical tests. The power may be increased by using larger sample sizes or, alternatively, by enlarging the‘effect size', by either taking an interest in a larger difference between the mean scores, or by minimizing the variability of the data.
The relationship between the root canal filling and post space preparation
Authors: CLEEN M. J. H. DE 
Published: September 2007

SummaryThe restoration of root treated teeth often requires the use of posts. Their use may affect the quality of the seal of the root canal filling. The various aspects of the relationship between root canal filling and post space preparation are discussed in this review. It is recommended that the use of posts should be avoided whenever possible. Where the preparation of post space is required, immediate removal of gutta‐percha using heated instruments and small Gates Glidden drills is the method of choice.
Experimentally induced dentoalveolar ankylosis in rats
Authors: HELLSING E. , ALATLI‐KUT I. , HAMMARSTRÖM L. 
Published: September 2007

SummaryDentoaiveoiar ankylosis is a common complication after replantation of teeth with injured periodontal ligaments. This is a serious complication for the tooth since it leads to progressive root resorption. In young individuals it may also cause infra‐occlusion and reduced develop‐ment of the alveolar process. The purpose of this study was to develop a method applicable to rats in order to follow the effect of systemic and local factors on the development of ankylosis and their possible effect on the length of the functional period of the ankylosed tooth before exfoliation.The maxillary first molars in adult rats were extracted. The periodontal ligaments were devitalized or removed before replantation of the teeth. Dentoalveolar ankylosis was clinically established 2 weeks after replantation. Induction was most reproducible after devitaiization or removal of the PDL cells with Dakin's solution and after keeping the rats on a liquid diet up to 3 weeks after replantation. Exfoliation of the teeth usually occurred 6 weeks after replantation.Histological examination showed that the PDL was replaced by bone. The ankylosed teeth showed root resorption to a varying degree. The resorption was in some cases occasionally located in the supra‐crestal part of the tooth. A bone‐like tissue in the root canal was a rather common finding. In one of the ankylosed teeth cartilage formation was found adjacent to the cementum.
An in vitro study of the quality of root fillings in teeth obturated by lateral condensation of gutta‐percha or Thermafil obturators
Authors: DUMMER P. M. H. , KELLY T. , MEGHJI A. , SHEIKH I. , VANITCHAI J. T. 
Published: September 2007

SummaryThe aim of this in vitro study was to assess the quality of root canal obturation and degree of linear apical dye penetration in teeth root filled with either laterally condensed gutta‐percha or Thermafil obturators, A total of 150 teeth with single roots were included in the study. All canals were prepared using a standard step‐back technique with anticurvature filing. Radiographs taken of the teeth to show the maximum degree of canal curvature were then exposed and the angle, radius and position of curvature determined. This information about the canals, together with their working length and diameter at end‐point, was used to divide the teeth into two experimental and two control groups. A total of eight teeth were excluded because of technical difficulties, 65 were filled with Thermafil obturators, 63 were filled with laterally condensed gutta‐percha whilst 14 teeth remained unfilled and acted as controls. Following obturation, the teeth were radiographed in two planes and the technical quality of fill assessed on a four‐point scale. All access cavities were then sealed and the teeth immersed in dye for 48 h before being split longitudinally. Linear dye penetration via the apical foramen was then assessed. Canal obturation with Thermafil obturators (0.7 min) was significantly quicker (P > 0.001) than lateral condensation (6.4 min). Apical extrusion of sealer and gutta‐percha occurred significantly more often with Thermafil obturators but there was little difference in the technical quality of the fillings and no significant difference in dye penetration. Under the conditions of this study, Thermafil obturators proved a satisfactory alternative to lateral condensation of gutta‐percha.
In vitro antimicrobial activity of calcium hydroxide cements on Streptococcus sanguis NCTC 7864
Authors: MILOSEVIC A. 
Published: September 2007

SummarySeveral studies have questioned the antimicrobial role of calcium hydroxide cements. This study assessed the antimicrobial activity of four commercially available calcium hydroxide cements on Streptococcus sanguis NCTC 7864 using inoculated Mueller‐Hinton growth medium. Growth curves from optical density analysis, pH measurements, and viability counts were compared over a 24 h period. Significant differences occurred (P > 0.05) between pH measurements but not the growth curves or the viability counts. All cements exerted a cidal effect although this cannot be attributed to an increase in alkalinity alone.
Periapical status and prevalence of endodontic treatment in an adult Dutch population
Authors: CLEEN M. J. H. DE , SCHUURS A. H. B. , WESSELINK P. R. , WU M.‐K. 
Published: September 2007

Summary:This study examined the prevalence of endodontic treatment in a group of 184 Dutch adults, and determined the periapical status of all teeth using panoramic radiographs. The results indicate that in this group, 2.3% of the teeth were root‐filled, and that 5.2% of all non‐endodonticallv treated teeth showed signs of periapical pathology. Around the apices of 39.2% of the endodontically treated teeth in this survey, radiographic signs of periapical pathology were observed. Using the level of the root canal filling as a criterion for evaluating the quality of the root canal treatment, 50.6% of the endodontic treatments were qualified as inadequate. There was a significant correlation between the presence of periapical pathology and underfilling of the root canal(s). 44.6% of the patient sample had at least one tooth with radiographic signs of periapical pathology, indicating a substantial future need for endodontic treatment.
The vibratory pattern of ultrasonic files driven piezoelectrically
Authors: AHMAD M. , ROY R. A. , KAMARUDIN A. GHANI , SAFAR M. 
Published: September 2007

SummaryThe pattern of oscillation of a Piezon‐Master 400 ultrasonic file driven by a piezoelectric transducer was studied in air and on water. In addition, the displacement amplitudes of the files were measured. The findings were compared with those observed with the Cavi‐Endo unit reported in another study (Ahmad 1969).It was observed that the file vibrated such that a standing wave was formed on the file and it exhibited points of maximum deflection (antinode) and points of minimum deflection (node) with the largest deflection occurring at the apical end. This pattern of oscillation was similar to that exhibited by the Cavi‐Endo file which employed a magnetostrictive transducer. However, the displacement amplitudes were very much higher than those exhibited by the Cavi‐Endo. It is considered that the 120° angle of the file holder inherent in the Piezon‐ Master 400 unit and the more effective power transmission with the piezoelectric transducer may have contributed to the large amplitudes.
Sealing ability of cermet ionomer cement as a retrograde filling material
Authors: AKTENER B. O. , PEHLIVAN Y. 
Published: September 2007

SummaryAn in vitro dye leakage study was performed to compare the sealing ability of high copper amalgam with cavity varnish and cermet ionomer cement with and without varnish when used as retrofilling materials. The root canals of 54 maxillary anterior teeth were instrumented and obturated with gutta‐percha and sealer. The apical 3 mm of the roots were resected and apical class I cavity preparations were made. The roots were then randomly divided into three groups and retrofilled with one of the experimental materials. After 72 h of immersion in India ink, the roots were cleared and evaluated for leakage with a stereomicroscope. Statistical analysis indicated that the cermet ionomer cement with varnish group had significantly less leakage than the amalgam group (P>0.0014) and the cermet ionomer cement without varnish group (P> 0.001). There was no significant difference between the other two groups (P< 0.05).
Success of pulpotomy in the management of hyperplastic pulpitis
Authors: CALISKAN M. K. 
Published: September 2007

SummaryHyperplastic pulpitis is a variety of chronic open pulpitis which is regarded as irreversible. This condition is usually treated by root canal treatment, unless coronal damage does not permit restoration, in which case extraction is indicated.In the present study, 24 permanent teeth of individuals, aged 10–22 years and diagnosed as hyperplastic pulpitis were treated by pulpotomy using an atraumatic surgical technique with calcium hydroxide alone. The treatment was successful in 22 teeth, according to the following criteria: absence of clinical symptoms, absence of any intraradicular or periradicular radiographic pathological changes, presence of dentine bridge detected by clinical examination and sometimes observed radiographically, and sensitivity to electrical stimulation. The follow‐up examination ranged from 12 to 48 months.The high frequency of clinical healing in this study appears to justify recommending pulpotomy as the treatment regime in selected cases of chronic hyperplastic pulpitis.
Fluid transport and bacterial penetration along root canal fillings
Authors: WU M.‐K. , GEE A. J. DE , WESSELINK P. R. , MOORER W. R. 
Published: September 2007

SummaryConvective transport of water from the coronal to the apical end of obturated root canals was determined by the movement of an air bubble in a capillary glass tube connected to the apex of the experimental root section using a headspace pressure of 120 kPa (1.2 atm). Water transport through existing voids in the obturated canals could be measured reproducibly in this way. The root canals of 60 human maxillary canines were filled with gutta‐percha and sealer by the cold lateral condensation technique. Thirty of these were first exposed to a small motile bacterium, Pseudomonas aeruginosa, growing in a reservoir at the coronal end of each root. After 50 days, two specimens allowed penetration of bacteria to a reservoir at the apical end. All the roots were then assessed quantitatively for convective transport of water. The results were divided into three defined categories: 39 obturated canals were in the‘bacteria tight’category, 14 canals in the 'slight leakage’and 7 canals in the‘gross leakage’category. The two specimens that showed bacterial penetration fell into the slight and gross leakage categories. The previous test for bacterial passage did not statistically influence the fluid transport pattern of these roots which was measured subsequently. These findings indicate that fluids transport through obturated root canals, most of which do not allow the passage of bacteria.
The effect of using files with altered tips in a sonic handpiece: an in vitro study
Authors: DUMMER P. M. H. , HUTCHINGS R. , HARTLES F. R. 
Published: September 2007

SummaryThe objective of this study was to establish the effect of altering the non‐cutting tips on Shaper flies during canal preparation with the MM1500 Sonic Air handpiece. A total of 90 simulated canals in clear resin blocks of various angles and positions of curvature were prepared using Shaper files activated by an MM 1500 Sonic Air handpiece. Thirty canals were prepared with unmodified files having non‐cutting tips, 30 canals were prepared with files which had their tips removed completely and a further 30 canals were prepared with files which had tips reduced by half. All canals were prepared using an identical preparation procedure which involved a linear filing motion and an anticurvature technique in curved canals. The parameters investigated included loss of canal length, weight loss from the blocks, smoothness of canal walls, transportation and overall shape of the prepared canals. The effect of altering the file tips was to increase significantly the loss of working distance and the prevalence of canal aberrations such as zips and danger zones. Altering the tips also had a detrimental effect on the pattern and extent of transportation as well as widening canals excessively in their apical third. Overall, under the conditions of this study, alterations to the non‐cutting tips of Shaper files was counterproductive and resulted in canals displaying many adverse features. Conversely, retention of the non‐cutting tips allowed canal preparation to proceed rapidly and effectively producing canal shapes which displayed many desirable features.
Light‐cured glass ionomer cement as a retrograde root seal
Authors: CHONG B. S. , FORD T. R. PITT , WATSON T. F. 
Published: September 2007

SummaryA light‐cured glass ionomer cement was investigated as a retrograde root seal, without a retrograde cavity. This was compared with the material used in a retrograde cavity, and with a conventional glass ionomer cement, as a seal. The adaptation and sealing ability of the test materials were assessed using a confocal optical microscope with a fluorescent dye.The root canals of 40 extracted human single‐rooted teeth were prepared and filled with gutta‐percha and sealer. All the teeth were subsequently apicected, then divided into four equal groups. In one group, a retrograde cavity was prepared, and the light‐cured glass ionomer cement was placed as a retrograde root filling. No retrograde cavities were prepared in the three remaining groups. The light‐cured glass ionomer cement was applied directly onto the apicected root face. Two different thicknesses of light‐cured glass ionomer cement were tested, a thin layer (≈1 mm) in one group, and a thicker layer (<1 mm) in another group. A conventional glass ionomer cement was used in the last group, and applied directly onto the root face in a single thickness (≈1 mm).In the group where the light‐cured glass ionomer cement was used in a retrograde cavity, the material was often well adapted to one cavity wall, but gaps were found on the opposite wall. The light‐cured and conventional glass ionomer cement retrograde root seals were well adapted to the root face, regardless of the thickness of material used.The thinly applied (≈1 mm) light‐cured glass ionomer cement retrograde root seals permitted the least leakage. This was significantly less than the light‐cured glass ionomer cement used with a retrograde cavity (P > 0.001). The greatest extent of dye penetration was found with the thick (< 1 mm) light‐cured and conventional glass ionomer cement (≈1 mm) root seals; the differences between these were not significant. The light‐cured glass ionomer cement was only suitable as a retrograde root seal when a thin layer (≈1 mm) was used.
Radicular cyst affecting a root‐filled human tooth: a long‐term post‐treatment follow‐up
Authors: NAIR P. N. R. , SJÖGREN U. , SCHUMACHER E. , SUNDQVIST G. 
Published: September 2007

SummaryApical periodontitis is caused primarily by microorganisms residing in the root canals of affected teeth. Nevertheless, there is convincing evidence implicating other independent factors that adversely affect the outcome of conventional root canal therapy. In this paper, morphological evidence is presented in support of die potential role of two endogenous factors that may interfere with post‐endodontic healing of the periapex. The specimens consisted of a surgical biopsy of an asymptomatic peri‐apical lesion which persisted for a follow‐up period of 44 months. The biopsy was processed for correlated light and electron microscopy. The lesion was characterized by the presence of a large central lumen lined by a stratified squamous epithelium. The most striking feature of the lesion was the presence of vast numbers of cholesterol crystals which congregated in the connective tissue surrounding the cyst cavity. Extensive light and electron microscopic investigation of the apical part of the root canal and the lesion foiled to reveal the presence of microorganisms.These findings strongly suggest that intrinsic factors like the accumulation of certain tissue break‐down products such as cholesterol crystals, and the cystic condition of the lesion itself, can adversely affect the healing process of the periapex following root canal therapy. Consequently, such apical lesions can remain refractory to conventional endodontic therapy for long periods of time.
A comparative scalability study of different retrofitting materials
Authors: ÖZATA F. , ERDILEK N. , TEZEL H. 
Published: September 2007

SummaryThe purpose of this study was to compare the sealing ability of high‐copper amalgam, glass ionomer cement, and silver glass ionomer cement as retrofitting materials when used with and without varnish. Seventy extracted human single‐rooted anterior teeth were instrumented and the root canals obturated with laterally condensed gutta‐percha and sealer. The apical 3 mm of each root was resected and a 2 mm‐deep apical Class I preparation cut. The roots were then randomly allocated to six groups of 10 teeth and retrofitled with one of die experiment materials. Group I comprised high‐copper amalgam; group 2, high‐copper amalgam with cavity varnish; group 3, glass ionomer cement without varnish: group 4, glass ionomer cement with varnish; group 5, silver glass ionomer cement without varnish; and group 6, silver glass ionomer cement with varnish. Two groups of five roots each were used as positive and negative controls.The root surfaces were coated with nail polish and specimens immersed in 2% methylene blue solution for 14 days. After vertical sectioning, dye penetration was examined under a stereomicroscope. The results of the study were analysed statistically. The sealing ability of the conventional glass ionomer cement with varnish was significantly better while dye penetration was higher in silver glass ionomer cement without varnish group than the other groups (P > 0.01).
Maxillary permanent incisors with two root canals: a report of two cases
Authors: REID J. S. , SAUNDERS W. P. , MACDONALD D. G. 
Published: September 2007

SummaryThe root canal treatment of permanent maxillary incisors with two root canals is reported. Two cases are presented, one success and one failure, with discussion regarding the different outcome, highlighting the need for careful radiographic investigation and patient management.
Dental anxiety: a cause for possible misdiagnosis of tooth vitality
Authors: ELI I. 
Published: September 2007

SummaryFear, anxiety and anticipation of pain are prepotent emotional and cognitive mediators of pain behaviour. As pain is often used as a parameter for evaluation of tooth vitality, existing dental anxiety may occasionally lead to possible misdiagnosis. A representative case is presented in which dental anxiety led to an initial misdiagnosis of endodontic pathology.
Root canal morphology of maxillary permanent first molar teeth at various ages
Authors: THOMAS R. P. , MOULE A. J. , BRYANT R. 
Published: September 2007

SummaryThe root canal anatomy and pulp chamber morphology of 216 maxillary permanent first molar teeth of known age was examined using a radiographic technique after infusion of the root canal system with a radiopaque sodium iothalontate gel. This technique proved to be a rapid and effective method for the examination of root canal morphology and is recommended when root canal anatomy needs to be examined before further investigations are carried out.Over 95% of palatal and disto‐buccal roots contained a single root canal. The mesio‐buccal root was more complex. All types of configurations were seen. Only 26% of mesio‐buccal roots showed a single canal.The pulp canal in all roots appeared to narrow at an early age. In the mesio‐buccal root, a definite two‐directional calcification pattern was apparent in most teeth by the age of 10. The rate of progress of root formation was very variable.There was no apparent relationship between the type of canal system in the mesio‐buccal root and the type of canal orifice present.The transverse cross‐sectional shape of the pulp chamber was trapezoidal in 81% of teeth.