bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of undergraduate endodontic teaching programmes in the United Kingdom and in some dental schools in Europe and the United States
Authors: DUMMER P. M. H.
Published: September 2007

Summary. The pattern of teaching root canal therapy within dental schools of the UK was determined and compared with that carried out within several dental schools in Europe and the USA. Although it appeared that ‘teachers of endodontics’ in the UK were advocating techniques adopted elsewhere, it was clear that, within the dental undergraduate curriculum as a whole, the teaching of root canal therapy was given a lower priority than that in some schools in Europe and the USA. Recommendations to remedy this unsatisfactory position are provided.
Vocational trainees' views of their undergraduate endodontic training and their vocational training experience
Authors: BROOKMAN D. J.
Published: September 2007

Summary. By means of a questionnaire, the views of recently qualified graduates, who were participating in vocational training schemes, on their undergraduate endodontic training and postquaiification experience were examined. On the basis of these findings suggestions are made as to what changes are necessary in their undergraduate training and how their skills can be further improved after qualification.
The organization and running of postgraduate endodontic ‘hands‐on’ courses
Authors: SAUNDERS E. M.
Published: September 2007

Summary. Considerable preparation, planning and detailed organization are necessary if endodontic ‘hands‐on’ courses are to be stimulating and worthwhile for participant and teacher alike. Projection facilities, lighting, seating and working surface requirements must be checked immediately on arrival at the venue.

The format, although flexible enough to allow for the wide range of knowledge and practical ability found within any one group, must adhere to and stress the current fundamentals in endodontic teaching. Not only can information and skill in diagnosis, root canal preparation and obturation be taught in a ‘hands‐on’ format, but rubber dam isolation techniques can also be practised very successfully.

Tutors must be prepared to demonstrate personally their clinical ability and experience of principles and techniques taught during the course.

Post‐course feedback can be an extremely useful means of ensuring that ‘hands‐on’ courses are relevant, with the appropriate practical emphasis required by the general dental practitioner, as well as the necessary stress on endodontic principles.
Continuing education in endodontology in The Netherlands
Authors: WESSELINK P. R.
Published: September 2007

Summary. The Netherlands Society for Endodontology has developed a 5‐year plan for continuing education that served as a guideline for two baste courses in endodontology. The 2‐day basic course has been attended by over 2000 dentists, and has been very much appreciated according to the evaluation outlined in this article. The development and content of these courses are described.

Over the past 10 years it has been shown that there is a high demand for continuing education in endodontology in The Netherlands, and that a properly designed and presented course may be very successful.
Streaming patterns produced around endosonic files
Authors: LUMLEY P. J. , WALMSLEY A. D. , LAIRD W. R. E.
Published: September 2007

Summary. Acoustic microstreaming is known ro be an important phenomenon associated with the use of clinically available cndosonic systems. However, it has proved difficult to calibrate its pattern and effectiveness around the oscillating file. An in‐vitro model system consisting of slow setting plaster was developed to demonstrate the activity of streaming around both ultrasonically and sonically activated files. For ultrasonic files, streaming occurred mainly in front of and behind the file, in contrast to the sonic file, where the plaster was disturbed evenly around it. With both types of file most activity occurred around the file tip, and became reduced towards the driver. Streaming patterns associated with the ultrasonic device were found to be dependent on the power setting of the instrument and whether the side of the file was constrained or lightly touched. The sonic device produced a large disturbance around the freely oscillating tip. Under load this streaming occurred along the whole length of the file, and was unaffected by constraint. This investigation demonstrated that streaming does occur with the instruments currently available, although it is dependent on their operating conditions. Clinical users of such equipment should be aware of the characteristic three‐dimensional patterns of streaming that occur around these endosonic files, in order to maximize their efficiency.
An SEM study of the effects of different irrigation sequences and ultrasonics
Authors: ABBOTT P. V. , HEIJKOOP P. S. , CARDACI S. C. , HUME W. R. , HEITHERSAY G. S.
Published: September 2007

Summary. The root canals of 30 extracted human teeth with single canals were prepared biomechanicaliy with hand instruments using a flaring technique. Three different irrigation regimes were used, with and without ultrasonic activation of a root canal file. The six irrigation sequences used in this study were as follows: Savlon. Savlon with ultrasound, EDTAC/NaOCl/ EDTAC, EDTAC/NaOCI/EDTAC with ultrasound, NaOCl/EDTAC/NaOCi, and NaOCl/EDTAC/NaOCl with ultrasound. Scanning electron microscopic (SEM) examination of the prepared root canal walls showed a complete smear layer when Savlon was used. Ultrasound reduced the amount of smear with Savlon, but did not do so significantly with the other irrigation regimes. The most effective irrigation regime for removing smear layer and other debris was EDTAC/NaOCl/EDTAC. In all groups there was a significant decrease in cleaning efficiency as the apical end of the canai was approached.
The effect of citric acid treatment on periodontal healing after replantation of permanent teeth
Authors: ZERVAS P. , LAMBRIANIDIS T. , KARABOUTA‐VULGAROPOULOU I.
Published: September 2007

Summary. The aim of this study was to evaluate the effect of surface demineralization on the healing of 120 replanted teeth in fifteen 8‐ to 16‐month‐old dogs. Replanted teeth were divided into two groups (A and B). In group A, teeth were replanted following planing of the entire root surface. In group B, teeth were replanted following planing and surface demineralization with citric acid. Replanted teeth were splinted for 7 days, and observation periods were 3, 14 and 56 days. A total of 95 teeth and their surrounding tissues were examined histologically under a light microscope.

Histological examination of specimens 3 days after replantation revealed that initial reunion between the root and the alveolar periodontal ligament fibres was via a fibrin‐like network in both groups. Fourteen days after replantation histologiesl observations showed superior healing in group B with regard to epithelial condition, periodontal ligament fibre reattachment to the root surface, resorption and functional arrangement of the periodontal ligament fibres. By 56 days after replantation, healing was superior in group A; group B was characterized by severe inflammatory and replacement resorption. These results indicated that surface demineralization had an initial positive effect, but later led to impaired healing.
Actinomycosis associated with a root‐treated tooth: report of a case
Authors: FIGURES K. H. , DOUGLAS C. W. I.
Published: September 2007

Summary. An unusual case of a persistent infection related to a root‐filled tooth is reported. Microscopical evaluation revealed the cause to be a large mass of Actmomyees‐like filaments, and microbiological culture yielded a low level of Actiaomyces israelii. The significance of such a presentation is discussed.
Predictability of radiographic diagnosis of variations in root canal anatomy in mandibular incisor and premolar teeth
Authors: NATTRESS B. R. , MARTIN D. M.
Published: September 2007

Summary. Four hundred and fifty‐five extracted mandibular incisor and 340 extracted mandibuiar pretnolar teeth were radiographed to assess the incidence of twin canals as visualized on radiographs taken in the mesio‐distal direction. The ability to detect the presence of these twin canals by viewing radiographs taken in the standard bucco‐lingual direction was then assessed. Using the guideline that ‘disappearance or narrowing infers division’ when viewing these radiographs resulted in a failure to diagnose one‐third of the twin canals.
A one‐stage calcific barrier technique in a root‐fractured incisor tooth: a case report
Authors: ROBERTSON C. U. J. , CUNNINGTON S. A.
Published: September 2007

Summary. This paper describes the use of calcium hydroxide powder as an immediate plug before root canal obturation in the case of a root‐fractured upper centra] incisor that had been unresponsive to 18 months of treatment to create a calcific barrier. The calcium hydroxide plug allowed both good condensation of the filling material and prevention of extrusion of the root filling material which could have been detrimental to continued healing of the fracture.
The influence of different root canal instruments on root canal preparation: an in vitro study
Authors: BRISEÑO B. M. , SONNABEND E.
Published: September 2007

Summary. Nine endodontic instruments from different manufacturers (Reamers, K‐files, Hedstrom files, K‐FIex files, Flexofiles, S‐files, Burns Unifiles, Flexicut files and Flex‐R files) were used to prepare 180 simulated root canals in resin blocks. The instrument's ability to reproduce a theoretical pre‐established ideal canal shape was assessed by comparing the original canal path with the resulting enlarged canal shape by a double exposure photographic method. The individual ability of each instrument to transport debris was also observed during instrumentation under a stereomicroscope. Regardless of the instrument type, none was able to reproduce ideal results; however, clinically acceptable results could be obtained with all of them. The coronal and apical debris transportation characteristics proved to be similar with all instruments.
Flare‐up rate of single‐visit endodontics
Authors: TROPE M.
Published: September 2007

Summary. The purpose of the study was to compare the flare‐up rate for single‐visit endodontics among teeth without radiographic or clinical signs of apical periodontitis, those with radiographic or clinical signs of apical periodontitis not previously root‐treated, and those with apical periodontitis where retreatment was performed.

All teeth were instrumented to a predetermined minimum size with a 0.5 per cent solution of sodium hypochlorite being used as the irrigant. The root canal was obturated without regard to the presence or absence of symptoms or diagnosis of the apical condition. The patients were given written postoperative instructions and a prescription for 600 mg ibuprofen to be taken if mild to moderate pain developed. If severe pain and/or swelling developed, the patient was instructed to telephone immediately and was considered to have had a flare‐up.

Teeth without signs of apical periodontitis did not have any flare‐ups. One flare‐up occurred in 69 teeth with signs of apical periodontitis not previously root‐treated. The majority of the flare‐ups (3 of 22 teeth) occurred in teeth with signs of apical periodontitis requiring retreatment.
The ability of the radiograph to determine the location of the apical foramen
Authors: OLSON A. K. , GOERING A. C. , CAVATAIO R. E. , LUCIANO J.
Published: September 2007

Summary. An in‐vitro radiographic study of human teeth was performed in order to evaluate the ability of radiographs to determine the location of the apical foramen. The tip of an endodontic file was positioned at the apical foramen of each canal in 117 extracted human teeth (213 canals) and in 56 teeth (92 canals) still within the alveolus of dried jaw specimens. Parallel radiographs were taken in a bucco‐lingual plane of all teeth. The tip of the instrument appeared to be at the root surface (apical foramen) in 82 per cent of canals. There was no significant difference in results between the teeth radiographed in alveolus of dried jaw specimens and extracted teeth when the radiographs were evaluated under a stereomicroscope.
The cumulative effect of disinfection, storage, histological fixation and demineralization on number and staining ability of Gram‐positive bacteria
Authors: WIJNBERGEN M. , VAN MULLEM P. J.
Published: September 2007

It has previously been shown experimentally using S.faecalis that the relative number of blue‐staining Gram‐positive bacteria was reduced by demineralizing agents as well as by disinfection (Wijnbergen & van Muilera 1987, van Mullem & Wijnbergen 1989). In this study the cumulative effect of disinfection, experimental period, fixation and demineralization was investigated. The use of additives to the fixative and the demineralizing agents to limit the toss of bluestaining bacteria was also studied. The numbers of bacteria were determined using a haemocytometer, and the percentage of blue‐staining organisms were ascertained from smears.

When compared with the start of the experiment, the sequence of disinfection with chlorhexidine, storage in PBS, fixation with neutral formaldehyde and demineralization with formic acid or EDTA appeared to reduce the relative numbers of Gram‐positive staining bacteria. For storage periods of 0 and 4 days the reduction factors were 100 and 600, respectively, using formic acid. These factors were 50 and 95, respectively, using EDTA. Addition of cetyl pyridinium chloride to the fixative and the demineralizing agents, and addition of neutral formaldehyde to the demineralizing agents lowered these reduction factors to 80 and 200, respectively, for formic acid, and 40 and 85, respectively, for EDTA.

If the results are extrapolated to animal experiments where disinfection, experimental period, fixation and demineralization form part of the experimental framework, even the lowest reduction in the number of blue‐staining bacteria could lead to false interpretation of tissue sections.
Comparison of six files to prepare simulated root canals. Part 1
Authors: AL‐OMARI M. A. O. , DUMMER P. M. H. , NEWCOMBE R. G.
Published: September 2007

A total of 300 simulated root canals of various angles and positions of curvature in clear resin blocks were prepared by hand using either K‐files, K‐Flex files, Flexo‐files, Flex‐R files, Hedstrom files or Unifiles. Each fife type was used to prepare 50 canals employing a linear filing motion and an anticurvature stepback technique. Part 1 of this two‐part report describes the efficacy of the files in terms of preparation time, instrument failure, loss of canal length and weight loss from the blocks. Two‐way analysis of variance confirmed that there was significant variation for each parameter between instruments, between canal types, and with interaction between instruments and canal types. Overall, preparation with Hedstrom files was significantly quicker than with any other file, whilst preparation with K‐files and K‐Flex files took significantly longer. Fracture and deformation of instruments occurred substantially less often with Flex‐R and Hedstrom files, but significantly more often with Unifiles. Loss of working distance occurred with all file types, but was significantly greater in canals prepared with K‐files. Unifiles and Hedstrom files were responsible for significantly more weight toss than the other files, whilst K‐files produced significantly less weight loss. Canals with rough undulating walls were created most often by Hedstrom files and Unifiles. Overall, under the conditions of this study, Flexofiles, Flex‐R files and Hedstrom files appeared to be substantially more effective than K‐files, K‐Flex files and Unifiles.
Comparison of six files to prepare simulated root canals. Part 2
Authors: AL‐OMARI M. A. O. , DUMMER P. M. H. , NEWCOMBE R. G. , DOLLER R. , HARTLES F.
Published: September 2007

A total of 300 simulated root canals of various angles and positions of curvature in clear resin blocks were prepared by hand using either K‐files, K‐Flex files, Flexo‐files, Flex‐R files, Hedstrom files or Unifiles. Each file type was used to prepare 50 canals employing a linear filing motion and an anticurvature stepback technique. Part 2 of this two‐part report describes the efficacy of the files in terms of the prevalence of canal aberrations, the amount and direction of canal transportation and the overall postoperative canal shape. Hourglass shaped canals were found in 4.5% of curved canals, the majority of these being created by K‐files and K‐Flex files. Perforations were seen in 6.3% of curved canals, the majority being produced by Flex‐R files and K‐files. Excessive removal of material from along the inner aspect of the canal curve occurred in 10.4% of canals, by for the majority being created by Hedstrom files. Transportation of canals was a consistent finding with all instruments. Two‐way analysis of variance revealed how significant differences in the absolute magnitude of transportation occurred between instruments, between canal types and by an interaction between instrument and canal type. In general, transportation was towards the outer aspect of the canal curve at the end‐point of preparation and the zip and elbow, but towards the inner aspect at the beginning of the curve. Further towards the orifice, transportation reverted to the outer aspect of the canal curve. In straight canals, one‐way analysis of variance indicated that significant differences (P < 0.05) occurred in the width of canals at their end‐point between instruments. In curved canals, two‐way analysis of variance indicated that the width of canals throughout their length varied significantly between instruments, between canal types and in some instances with interaction between instrument and canal type. Under the conditions of this study.
Variables affecting electronic root canal measurement
Authors: WU Y.N. , SHI J. N. , HUANG L. Z. , XU Y. Y.
Published: September 2007

This study was conducted in two parts. In the first part, 20 single‐rooted teeth that had been scheduled for extraction were investigated. The electronic root canal lengths were measured in vivo with a Dental Sono‐Explorer type Y‐III, and the actual canal lengths were measured after extraction of the teeth. The rate of agreement of the two measurements was 77.5% within a range of ±0.5 mm, while it was 100% at ±2.0mm, which is acceptable clinically. In the second part, there were 19 simulated canals whose lengths and apical foramen sizes were known beforehand. Experiments revealed a negative correlation between the areas of the apical foramina and the difference between the electronic and the actual root canal lengths. This relationship was shown by the linear regression equation:

ŷ= 0.6 − 1.6x.

With the exception of the smallest areas of foramina, electronic root canal length measurements were less than the actual lengths.
A method for experimental dental radiography
Authors: FORSBERG J.
Published: September 2007

An apparatus was designed for experimental dental radiography, which permitted separate adjustment of the subject, target and film. The precision of the apparatus was tested by radiographing a test subject, consisting of small steel globes embedded in a plastic plate. The subject was placed in the apparatus and exposed 30 times on dental X‐ray film with different adjustments of angles and distances. All exposures were repeated after readjustment of the same form. Three linear distances between pairs of the projected steel globes were selected and measured on each radiograph. Depending on the different orientations of film, target and subject, the distances measured ranged from 9.0–11.1 mm, from 7.0–10.7 mm and from 12.7–17.3 mm, respectively. From the measurements on the radiographs the error of method was calculated to be 0.07–0.08 mm and the error of measurement to be 0.05–0.06 mm. The precision of the apparatus was thus found to be adequate for measurement of differences in small, but clinically relevant, distances.
Diagnostic dilemma: an unusual presentation of an infected nasopalatine duct cyst
Authors: GULABIVALA K. , BRIGGS P. F. A.
Published: September 2007

The pertinent literature on nasopalatine duct cysts is reviewed. A case is reported in which a nasopalatine duct cyst infected by Actinomyces presented clinically with unusual features. The clinical findings could have been confused with an early acute periapical abscess arising from an incisor tooth. The relevant aspects of diagnosis are discussed.
Quantitative radioactive analysis of microleakage of four different retrograde fillings
Authors: DANIN J. , LINDER L. , SUND M.‐L. , STRÖMBERG T. , TORSTENSON B. , ZETTERQVIST L.
Published: September 2007

Sealing properties of four different retrograde filling materials were investigated in vitro. Radioactive isotopes were applied in the root canal, and leakage into an extraradicular fluid was measured at regular intervals. The method permitted repeated observation of the specimens over prolonged periods of time. Forty single‐rooted human teeth were biomechanically instrumented and obturated using calcium‐hydroxide paste. Following obturation, an apicectomy was performed and retrograde cavities were filled with four different materials: group 1, non γ2. amalgam (Amalcap): group 2, glass ionomer cement (Ketac Silver); group 3, calcium‐hydroxide‐based root canal sealer (Sealapex); group 4, composite resin (Palfique Light‐S). After removal of the calcium hydroxide, the teeth were immersed in a fluid. An isotope solution was then placed in the root canals. Samples were taken from the fluid at 0, 3, 7, 28, 56, 105, 210, 285 and 376 days to determine the radioactivity. It was found that Sealapex and Palfique Light‐S showed significantly less leakage than amalgam and glass ionomer cement, which had the highest apical leakage.
Systemic release of corticosteroids following intra‐dental use
Authors: ABBOTT P. V.
Published: September 2007

Concern has been expressed in the past that the use of corticosteroids within root canal medicaments or pulp capping agents may lead to deleterious systemic effects. Calculations of the highest possible amounts that could be used, plus an analysis of the release and diffusion characteristics, and comparisons with known endogenous levels of corticosteroids, reveal that the intra‐dental use of Ledemnix paste and Ledermix cement is unlikely to result in any systemic side‐effects.
Tissue responses to Hydron, assessed by intraosseou simplantation
Authors: REID R. J. , WILSON D. F. , CHAU K. K. , HEITHERSAY G. S. , HEIJKOOP P. S.
Published: September 2007

Teflon tubes containing freshly mixed, polymerized Hydron root canal filling material, folly set AH26 or Teflon were implanted into the mandible of guinea pigs andassessedhiilogically at 2 days. l,2,4,12 and 26 weeks. None of the materials tested elicited signs of overt or significant tissue damage, and polymerized Hydron was assessd to be as biocompatible as folly set AH26 and Teflon. Bone formed in very close apposition to the polymerized Hydron. whereas a soft tissue capsule separated the regenerated bone loom implants of AH26 and Teflon.
A comparison of leakage of filling materials in demineralized and non‐demineralized resected root ends under vacuum and non‐vacuum conditions
Authors: PETERS L. B. , HARRISON J. W.
Published: September 2007

A study was conducted to compare the marginal apical leakage of root‐end filling materials under vacuum and non‐vacuum conditions, and to assess the effect of demineralization by application of citric acid to the root ends on the apical marginal leakage of root end filling materials. The root canals of 148 extracted human canines and premolars were handfiled and sealed with gutta‐percha and Roth's 801 sealer using cold lateral condensation. The teeth were divided into 8 groups that received retrofilling materials. The materials tested were amalgam, IRM and gutta‐percha/sealer with and without successive application of citric acid. Half of the specimens were placed under vacuum conditions in methylene blue dye, and the other half were placed in the dye for the same time period without exhausting air from the flask. The teeth were split longitudinally and the extent of dye penetration was determined with a stereomicroscope and eyepiece micrometer. The most evident difference in dye penetration was found between the positive control groups. Under vacuum conditions, the positive controls showed complete penetration of the unobturated canal system with dye. With passive immersion only partial penetration of the unobturated canal system occurred. Application of citric acid to the root end did not adversely affect the seal of amalgam, IRM or gutta‐percha/sealer.
Clinical detection of the minor mesiobuccal canal of maxillary first molars
Authors: TING P. C. S. , NGA L.
Published: September 2007

One hundred extracted maxillary first molars from a South East Asian population were sectioned at a level below the roof of the pulp chamber. The detection of the minor mesiobuccal canal was determined on the pulpal floor using a size 08 file. When the canal was not detected by this technique, its presence or absence was then determined by sectioning the mesiobuccal root transversely, and the position of the extra canal was explored from the cut end. It was found that by modifying the outline of the access cavity, and by widening and deepening the groove running palatally from the major mesiobuccal canal up to a depth of 0.5 mm and a distance of 2.0 mm, the visibility of the extra mesiobuccal canal orifice was greatly improved. This study showed that more than 50% of maxillary first molars had a minor mesiobuccal canal, and 19% of these canals could not be detected clinically.
Periradicular healing and apical closure of a non‐vital tooth in the presence of bacterial contamination
Authors: GUTMANN J. L. , FAVA L. R. G.
Published: September 2007

This case report addresses the periradicular tissue response and root‐end closure of a maxillary central incisor in the presence of bacterial contamination. The implications for the control of bacteria through the use of calcium hydroxide and/or systemic antibiotic coverage are considered in the light of scientific evidence and clinical treatment.
Failure characteristics of endodontically treated premolars restored with a post and direct restorative material
Authors: HUYSMANS M.‐C. D. N. J. M. , PETERS M. C. R. B. , PLASSCHAERT A. J. M. , VAN DER VARST P. G. T.
Published: September 2007

Ninety‐one extracted maxillary premolar teeth were restored with a prefabricated post and amalgam, composite resin or glass‐cermet core. Each group was again divided into three groups of 9–13 teeth to be subjected to an increasing load in one of three standardized directions (10, 45 and 90° to the long axis of the tooth). Failure load and characteristics of failure were recorded. The glass‐cermet‐restored teeth had a lower strength than the other groups for every load direction (Student's t‐test: P < 0.01). Amalgam and composite resin groups showed a significant difference only for the 10% loading condition (Student's test: P < 0.02). Teeth restored with amalgam cores displayed a higher mean failure load, in combination with a 46% occurrence of root fracture.
Root Fractures in permanent teeth: a clinical review
Authors: YATES J. A.
Published: September 2007

A retrospective study of 22 root fractures in 21 patients was performed. Ten patients were less than 11 years of age, and boys were involved more often than girls. Ten patients had more than one injured tooth, but there was no case of alveolar fracture. Twenty‐one of the teeth were upper central incisors. Only 11 teeth were seen within the first week, so that not all teeth were splinted and not all displaced teeth were repositioned. Long‐term clinical and radiographic review showed that loss of vitality of the coronal pulp could not be reliably detected for at least 1 year. No tooth became abscessed or developed a sinus tract, and resorption of bone at the fracture line was observed in only one out of five non‐vital teeth. Lack of displacement and placing of a splint increased the chances of the pulp remaining vital and healing of the fracture occurring with hard tissue. Sclerosis of the coronal pulp occurred mainly when healing was by connective tissue. The apical pulp always remained vital, and there was sclerosis of the apical pulp in almost every case.
Asymmetry of the root canal foramen
Authors: BLAŠKOVIČ‐ŠUBAT V. , MARIČIČ B. , ŠUTALO J.
Published: September 2007

Deviation of the major apical foramen from the anatomical root apex is a recognized phenomenon. To determine the frequency, position and mean distance of the major apical foramen from the anatomical root apex, 230 roots of permanent teeth were examined stereo‐microscopically and radiographically. Radiographic analysis was used to establish how accurate the conventional radiograph was in displaying such a deviation.

The frequency of deviation of the major foramen, determined stereomicroscopically, was 76%, and depended on the type of teeth examined. Radiographic analysis of the same sample revealed 57% of root canals had asymmetry of the root canal foramen. Agreement of stereomicroscopic and radiographic findings was found to be 61%. The most frequent deviation of the major foramen was on the distal root surface (29%), but this was not statistically significant. The mean distance between the deviation of the major foramen and the anatomical root apex was 0.99 mm. The study indicates that the clinician should consider deviation of the foramen during root canal treatment, as the deviation could not easily be detected radiographically.
A survey of endodontic procedures performed by practitioners in limited practice
Authors: HARTY F. J.
Published: September 2007

Patients are sometimes referred for treatment to dentists who limit their practices to endodontics. A survey of consecutive referrals to seven such dentists was undertaken. The most common reasons for such referrals were (i) for the retreatment of a tooth with a previous root filling, (ii) because the referring dentist was unable to control pain and/or swelling, or (iii) because the referring dentist was unable to diagnose the endodontic problem. Only 60 (12.8%) of the 469 reasons reviewed were in teeth that were symptomless, uncomplicated and untouched by the referring dentist.
The use of glass ionomer as a root canal sealer—a pilot study
Authors: SAUNDERS W. P. , SAUNDERS E. M. , HERD D. , STEPHENS E.
Published: September 2007

The use of a resin‐based glass ionomer as an endodontic sealer was studied in vitro. The root canals of extracted single‐rooted human teeth with mature apices were prepared using a stepback technique. Subsequently, the smear layer was removed with 40% citric acid and the canals obturated using lateral condensation of cold gutta‐percha and a resin‐based glass ionomer as the sealer. The relationship between the sealer and the wall of the root canal was studied using scanning electron microscopy. The shear bond strength of gutta‐percha to this glass ionomer was also determined. Finally, the uptake of fluoride into the wall of the root canal was studied using scanning electron microprobe analysis after storage for 2 weeks, 1 month and 3 months following root filling with gutta‐percha and glass ionomer cement. The results showed that removal of the smear layer allowed the sealer to enter some of the dentinal tubules. This was observed most frequently in the middle third of the root canal, where there was good adaptation of the sealer. The shear bond strength of gutta‐percha to the glass ionomer sealer was not significantly different from that obtained between gutta‐percha and a proprietary zinc oxide‐eugenol endodontic sealer. The concentration of fluoride in the dentine in the coronal part of the root canal increased after obturation with gutta‐percha and the glass ionomer sealer at every time interval. The increase in fluoride concentration varied widely between teeth. It is concluded that a resin‐based glass ionomer cement may have potential as a root canal sealer.
The effect of smear layer upon the coronal leakage of gutta‐percha root fillings and a glass ionomer sealer
Authors: SAUNDERS W. P. , SAUNDERS E. M.
Published: September 2007

The effect of the removal of the smear layer on coronal leakage of root fillings was studied using two sealer cements. Sixty single‐rooted teeth with mature apices were prepared chemomechanically using a modified double‐flared technique with non‐cutting tipped files and copious irrigation with 2% sodium hypochlorite. The teeth were randomly allocated to four groups of 15 teeth each. Two groups were treated with 40% citric acid to remove the smear layer. Two groups of teeth, one with and one without smear layer, were filled by lateral condensation of gutta‐percha with either Tubliseal or a resin‐based glass ionomer, Vitrebond. The teeth were stored for 1 week, thermocycled, and the extent of coronal leakage determined for each group after immersion in Indian ink for 90 h. The teeth were demineralized, dehydrated and immersed in methyl salicylate which rendered them transparent. Linear measurement of dye penetration was recorded. The mean depth (± SD) of leakage for the groups in which the smear layer was left intact was 4.26 ±1.53 mm and 6.83 ± 1.65 mm for the Vitrebond and Tubliseal, respectively. When the smear layer had been removed, the mean depth of leakage for the Vitrebond group was 1.13 ±0.29 mm, and 3.72 ± 1.23 mm for the Tubliseal group. There was a statistically significant difference in leakage between the groups (P > 0.001). With both sealers, those teeth in which the smear layer had been removed showed less leakage than the specimens in which the smear layer was left intact (P > 0.001). The Vitrebond specimens leaked less than the teeth that were root filled using Tubliseal, both when the smear layer was intact and when it was absent (P > 0.001).
The apical seal of root canal sealing cements using a radionuclide detection technique
Authors: CANALDA‐SAHLI C. , BRAU‐AGUADE E. , SENTIS‐VILALTA J. , AGUADE‐BRUIX† S.
Published: September 2007

The aim of this study was to evaluate the apical seal obtained with various root canal sealing cements using a new method based on the use of a radionuclide and an external detection technique. A total of 150 maxillary incisors and canines, which had been kept in saline solution, were used. The root canals were instrumented with a stepback technique and circumferential filing. Six experimental groups and two control groups were randomly formed. Each experimental group was obturated by a lateral condensation technique with gutta‐percha points and a different seating cement (two based on zinc oxide‐eugenol cement, two based on resins and two on calcium hydroxide); the positive control used gutta‐percha without sealing cement, while in the negative control the apex was covered with nail varnish, leaving the root canal empty. The apical leakage was measured using an external detection technique after submerging the root apices in a solution containing the radioisotope metastable 99Tc. No leakage was observed in the negative control group. There was a large difference between the leakage observed in the positive control group and the experimental groups. The best seal was obtained using Sealapex cement, which dif‐feredsignificantly from AH26, Tubli‐Seal and Diaket; there was no significant difference between the latter. The poorest results were obtained with Endomethasone and CRCS; there was a significant difference between these and the previous three sealing cements.
Human pulpectomy: incidence of postoperative pain using two different intracanal dressings
Authors: FAVA L. R. G.
Published: September 2007

A clinical study using vital maxillary central incisors was performed to evaluate the incidence of postoperative pain after pulpectomy and dressing with a corticosteroid‐antibiotic preparation or a calcium‐hydroxide paste. Sixty teeth from 45 patients were prepared and dressed on the first visit and re‐evaluated 7 days later. No difference was observed in the incidence of postoperative pain between the two groups.
Endodontic leakage studies reconsidered. Part I. Methodology, application and relevance
Authors: WU M. ‐K. , WESSELINK P. R.
Published: September 2007

An 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

The 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

The 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

Dentoaiveoiar 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

The 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

Several 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

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

The 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

An 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).