bluuebunny/crossref_metadata_2025 huggingface dataset:
Sealing properties of Ketac‐Endo glass ionomer cement and AH26 root canal sealers
Authors: DE GEE A. J. , WU M‐K. , WESSELINK P. R.
Published: September 2007

Sealing capacity, setting shrinkage and setting time of a recently introduced glass ionomer cement Ketac‐Endo were compared with that of a conventional sealer AH26. Sixty half‐cylinders, 8 mm long, 4 mm in diameter, made from fresh bovine root dentine, had their smear layer removed before being cemented together while separated by 1‐mm spacers. This resulted in a group of 15 cylinders cemented with Ketac‐Endo and a similar group with AH26. After coating the lateral surface with nail varnish, one end of each cylinder was connected with a tube filled with water under 120 kPa (1.2 atm) pressure. At the other end the fluid leaking through the cemented interface of the cylinders was measured by displacement of an air bubble in an attached standard glass capillary. In this particular set‐up where the sealers were used in bulk between two opposing dentine surfaces, Ketac‐Endo leaked significantly more than AH26. After shear loading the cemented specimens, it was found that the area of adhesive failure was 88% for Ketac‐Endo, and 15% for AH26. The leakage pathways were most probably at the dentine‐sealer interface for Ketac‐Endo and through cohesive fractures in the sealer for AH26.
A study in vitro of threaded titanium pins used for retrograde obturation of root canals
Authors: DANIN J. , LINDER L. , RAMSKÖLD L. , SUND M.‐L. , STRÖMBERG T. , TELME I. , TORSTENSON B.
Published: September 2007

The microleakage of four retrograde filling materials was compared in vitro. Fifty‐three single rooted teeth were instrumentated and root filled with resin chloroform and gutta‐percha. The gutta‐percha cones were left extruding from the access opening. All teeth were apicected and retrograde fillings placed. The materials used were a non γ2 amalgam (Amalcap), a glass ionomer cement (ChemFil II), threaded titanium pins cemented with a glass ionomer cement (ChemFil II) and identical titanium pins cemented with a silicone material (Adheseal). After removal of the gutta‐percha with tweezers, a radioactive isotope solution was placed in the teeth. Extraradicular samples were taken at 3, 7, 28, 77 and 104 days. All retrograde fillings showed some microleakage. The group with titanium pins cemented with silicone showed the least leakage: significantly less than the teeth with glass ionomer cement (P < 0.01) and with amalgam (P < 0.01). No significant differences were found between other groups.
Resistance to fracture of endodontically treated premolars restored with new generation dentine bonding systems
Authors: HERNANDEZ R. , BADER S. , BOSTON D. , TROPE M.
Published: September 2007

MOD cavities in 60 endodontically treated teeth were restored using six different methods. Copper rings were filled with commercial hard‐setting cement and the teeth were placed up to the level of the cemento‐enamel junction. The teeth were grouped according to restorative method, mounted in an Instron TT machine, and the buccal walls subjected to a slowly increasing compressive force until fracture occurred. The force of fracture of the walls of each tooth was recorded and the results in the various groups compared. All teeth fractured in a similar manner irrespective of the restorative method used. All groups restored with the newer bonding system had higher resistance to fracture than those restored with an acid etch chemically cured composite resin technique. The groups restored with Den‐Mat Tenure Core Paste or a Variglass VLC base and Prisma APH were significantly stronger than the acid etch Concise restored teeth (P<0.05). No statistically significant differences were found between the other groups (P>0.05).
Association of specific bacteria with some endodontic signs and symptoms
Authors: GOMES B. P. F. A. , DRUCKER D. B. , LILLEY J. D.
Published: September 2007

Although a wide range of bacterial species has been isolated from infected dental root canals it remains necessary to determine whether any particular group of such bacteria is associated with specific endodontic symptoms and clinical signs. In this study 30 root canals were examined microbiologically; of these, 14 were associated with pain, 20 with tenderness to percussion, 23 presented with wet root canals, seven with swelling, five with purulent exudate and four with a sinus. Clinical and microbiological correlation was observed particularly with regard to pain where anaerobes were isolated from 93% of painful canals and only from 53% of painfree canals. The former yielded means of 2.5 anaerobic species and 1.6 facultative species per canal, compared with 1.5 and 2.4 in painfree canals. Prevotella spp. were isolated from 64.2% of painful canals and 12.5% of painless canals (P<0.01) similarly, peptostreptococci were isolated from 71.4% of painful and 31.3% of painless canals (P<0.05). It was concluded that a significant association exists between pain and the presence of Prevotella and Peptostreptococcus spp. in dental root canals.
Leakage of four root canal sealers at different thicknesses
Authors: WU M‐K. , DE GEE A. J. , WESSELINK P. R.
Published: September 2007

Sealers play a key role in sealing the root canal system. Fluid transport under a headspace pressure of 50 kPa (0.5 atm) through four sealers, AH26, Ketac‐Endo, Sealapex and Tubli‐Seal at a thickness of 0.05, 0.25 or 3 mm, was determined using 240 standard bovine root sections which were obturated with either sealer only or sealer combined with standard gutta‐percha cylinders. AH26 and Sealapex sealed more tightly than Ketac‐Endo or Tubli‐Seal when used without gutta‐percha; AII26, Ketac‐Endo, and Sealapex sealed more tightly than Tubli‐Seal when the sealer layer was 0.25 mm thick, while Ketac‐Endo sealed more tightly than the other three sealers when the sealer layer was 0.05 mm thick. These findings indicate that the thickness of the sealer layer influences the sealing ability of a root canal filling.
Influence of sodium hypochlorite on the permeability and structure of cervical human dentine
Authors: BARBOSA S. V. , SAFAVI K. E. , SPÅNGBERG L. S. W.
Published: September 2007

The effect of 5% sodium hypochlorite and 35% hydrogen peroxide on dentine samples in vitro was investigated. It was demonstrated that both 5% NaOCI and 35% H2O2 depletes the dentine, which can be recorded as weight loss. Sodium hypochlorite removes approximately 14% of dry weight from dentine samples in 24 h; hydrogen peroxide is half as destructive.

The hydraulic conductance (Lp) of dentine after treatment with NaOCI is increased over 100%. It is suggested that the use of high concentrations of sodium hypochlorite during root canal treatment may negatively affect the integrity of the root canal wall thereby allowing increased access of caustic bleaching fluids to cervical vital tissues.
Ultrasonic root‐end preparation Part 2, Microleakage of EBA root‐end fillings
Authors: SAUNDERS W. P. , SAUNDERS E. M. , GUTMANN J. L.
Published: September 2007

The effect of three methods of root‐end preparation, following apical resection, on the apical seal of root‐end fillings, was studied in vitro. Root canals of 116 single‐rooted teeth with mature apices were prepared chemo‐mechanically and obturated with gutta‐percha and sealer. The root ends were resected with a diamond bur under water coolant and were prepared as follows: group I a size 010 round bur was used to prepare an apical cavity 2–3 mm down the long axis of the root; group II treatment as per group 1 followed by a 60‐s rinse with a solution of 10:3 (10% citric acid: 3% Fe2Cl3); and group HI an ultrasonic retrotip was used to prepare a 2–3 mm deep apical cavity. The root end was restored with an EBA cement. Apical leakage was determined using India ink after 7 days and 7 months. The teeth were demineralized, rendered transparent and linear dye penetration was recorded. Results showed that there was no significant difference in leakage between the groups at each time interval (P>0.05) but there was increased leakage after 7 months (P<0.01). Cracking of the root surface was seen most often with the ultrasonically prepared roots (P<0.001).
Efficacy of sterilization of endodontic files after autoclaving in a synthetic sponge
Authors: BOYD K. S. , SONNTAG K. D. , CRAWFORD J. J.
Published: September 2007

A common way of sterilizing endodontic files for clinical use is to insert them into synthetic sponges. The files are sterilized in the sponge, and the sponge is then used on the patient tray for ease of file retrieval. The ability to sterilize the files in a sponge has been questioned. The purpose of the present investigation was to evaluate the sterility of files and spore strips following autoclaving in a sponge. Commercial spore strips and contaminated endodontic files were inserted into sponges, sealed in sterilization pouches and autoclaved. The spore strips and the files were removed from the sponge and cultured for growth of microorganisms. Results show that no microbes were cultured from spore strips or contaminated files after autoclaving them in the sponges sealed in autoclave pouches. These results indicate that the insertion of files into the sponges used in this study does not obstruct the autoclaving process.
Torsional properties of stainless steel Canal Master U and Flexogates
Authors: CAMPS J. J. , PERTOT W. J.
Published: September 2007

The purpose of this study was to evaluate and compare the torsional properties of Flexogates and Canal Master U instruments. Torsion and bending tests were performed on both designs of instrument according to ANSI/ADA specification number 28 criteria and standards. Ten instruments of each size, sizes 25 to 50 were used for each test. Four parameters were measured: the moment at failure, the rotation at failure, the separation point at failure and the bending moment at a 45° angle. Both instruments satisfied ANSI/ADA standards for rotation at failure and bending moment. Canal Master U satisfied ANSI/ADA standards for moment at failure in all sizes except 45 and 50. Flexogates did not satisfy these standards in all sizes except 50. Flexogates separated at the end of the shaft whereas Canal master U separated just behind the cutting head. Both instruments showed favourable physical properties for preparing root canals.
Endodontic and restorative management of incompletely fractured molar teeth
Authors: GUTMANN J. L. , RAKUSIN H.
Published: September 2007

The treatment of fractured teeth poses significant problems for the practitioner. However, once the treatment planning decision has been made to attempt to retain the tooth, various practical regimens are available to effect this goal. This paper addresses the specific use of glass ionomer in the restorative management of incompletely, vertically fractured molar teeth integrated with specific root canal treatment techniques.
Periapical status of endodontically treated teeth in relation to the technical quality of the root filling and the coronal restoration
Authors: RAY H. A. , TROPE M.
Published: September 2007

summary

The purpose of this study was to evaluate the relationship of the quaality of the coronal restoration and of the rot canal obturation on the radiographic periapical status of endodontically treated teeth. Full‐mouth radiographs from randomly selected new patient folders at Temple University Dental School were examined. The first 1010 endodontically treated teeth restored with a permanent rstoration were evaluated independtly by two examiners. Post and core type restorations were excluded. According to a predetermined radiographic standard set of criteria, the technical quality of the root filling of each tooth was scored as either good (GE) or poor (PE), and the quality of the coronal restoration similarly good (GR) or poor (PR). The apical one‐third of the root and surrounding structures were then evaluated radigraphically and the periradicular status categorized as (a) absence of periradicular inflammation (API) or (b) presence of periradicular inflammation (PPI). The rate of API for all endodontically treated teeth was 61.07%, GR resulted in significantly more API cases than GE, 80%, versus 75.7%. PR resulted in significantly more PPI cases than PE, 30.2% versus 48.6%. The combination of GR and GE had the highest API rate of 91.4%, significantly higher than PR and PE with a API rate of 18.1%.
Localization of chondroitin sulphate and dermatan sulphate in human dental pulps — an immunohistochemical study
Authors: BARTOLD P. M. , SCHLAGENHAUF U.
Published: September 2007

The distribution of dermatan sulphate and chondroitin sulphate in human dental pulps has been assessed using monoclonal antibodies and immunoperoxidase localization techniques. The pulpal tissues were reacted with specific antibodies following pretreatment of the sections with chondroitinase ACII or chondroitinase ABC. Both the 4‐ and 6‐sulphated isomers of chondroitin sulphate were detected in the tissues studied. Very little derrmatan sulphate could be detected. These glycosaminoglycans appeared throughout the pulpal connective tissues with a particularly strong localization to the region adjacent to the odontoblastic and predentine layers. Such distribution strongly implicates chondroitin sulphate in the mineralization process of human dentine.
Comparison of Radiovisiography with radiographic film in root length determination
Authors: ONG E. Y. , FORD T. R. PITT
Published: September 2007

Radiovisiography is a digital intraoral radiographic imaging system requiring a substantial reduction of radiation dosage to the patient over film. For Radiovisiography to replace film, it must be shown to be as efficacious. In this study, a technique of obtaining Radiovisiography and D‐speed film images from the same X‐ ray beam was developed with the use of rare‐earth filters. The quality of the resultant radiovisiographic images was verified in vitro with pure radiovisiographic images of teeth in a dried mandible with soft tissue simulation. Two examiners compared Radiovisiography with D‐speed film for 20 root length estimations using the same in‐vitro model. A clinical study was then carried out on mandibular molars of patients undergoing endodontic treatment, where 35 root lengths were obtained. The results of both in vitro and clinical studies showed no statistical differences in the estimated root lengths using the two imaging systems. The measuring grid available in the Radiovisiography unit produced similarly accurate results. Furthermore, the clinical study demonstrated the effective use of Radiovisiography during root canal treatment, with instant images.
Sealability of the Trifecta™ technique in the presence or absence of a smear layer
Authors: LLOYD A. , THOMPSON J. , GUTMANN J.L. , DUMMER P. M. H.
Published: September 2007

The aim of this in vitro study was to assess the sealability of a recently introduced thermoplasticized gutta‐percha technique (Trifecta, Hygenic Corp., OH, USA) in the presence or absence of a smear layer. A total of 100 teeth with single straight root canals were included in the study. The teeth were decoronated and the canals prepared with a modified double‐flared technique under constant irrigation with 2.5% sodium hypochlorite solution. The apical matrix was prepared to size 40 and apical patency subsequently confirmed with a size 10 file. Four teeth were discarded for technical reasons and the remaining 96 allocated randomly into two groups of 44 teeth and a group of eight teeth which acted as controls. Canals in group 1 were obturated randomly with either cold lateral condensation of gutta‐percha or with the Trifecta technique. Canals in Group 2 were rinsed with 17% REDTA to remove the smear layer and then obturated with lateral condensation or the Trifecta technique. All teeth were suspended in India ink for 9 days, demineralized, and rendered transparent prior to the assessment of apical linear dye penetration. Apical extrusion of sealer and gutta‐percha occurred commonly but there was no significant difference between the four obturation groups. However, overall, there was significantly more extrusion of sealer with the Trifecta technique compared with lateral condensation (P<0.05). The majority of canals (79 out of 88) had no evidence of apical leakage and there was no significant difference between the groups. The prevalence of sealer and gutta‐percha penetration into the dentinal tubules was significantly different between the four obturation techniques (P<0.01) and significantly more common in the absence of the smear layer (P<0.001). Under the conditions of this study, the Trifecta technique
The guided tissue regeneration principle in endodontic surgery: one‐year postoperative results of large periapical lesions
Authors: PECORA G. , KIM S. , CELLETTI R. , DAVARPANAH M.
Published: September 2007

Twenty patients with large endodontic lesions, which failed to respond to conventional endodontic therapy, were selected for this study. The lesions had a radiographic diameter of at least 10 mm, were removed by periradicular surgery, before retrofilling the apices with either super EBA or dessicated zinc oxide‐eugenol. In 10 test sites large e‐PTFE membranes (Gortex) were placed to cover the lesions, while at the control sites the lesions were not covered before resuturing. Radiographic analysis of the lesions at 3, 6, 9 and 12 months revealed that lesions covered with the membranes healed quicker than the control lesions, and that the quality and quantity of the regenerted bone was superior when membranes were used. Results of the study indicate that guided tissue regeneration (GTR) principles can be effectively applied to the healing of large periapical lesions, especially in through‐and‐through lesions.
Factors affecting the clinical efficiency of ultrasonic endodontics: a scanning electron microscopy study
Authors: CAMERON J. A.
Published: September 2007

The purpose of this pilot study was to investigate some of the clinical variables in ultrasonic endodontics. Forty extracted human teeth with a single, straight root 21–25 mm in length were prepared using combinations of the following variables: hand or ultrasonic instrumentation; apical seat prepared to file sizes 35, 40, 45 or 50; lml of water, 4% sodium hypochlorite or EDTAC as irrigant between each instrument size; three brands of ultrasound generator and inserts; a ‘low’, ‘medium’ or ‘high’ effective power output; a tuned or untuned circuit; post‐instrumentation ultrasonic irrigation with either 4% sodium hypochlorite, EDTAC, or the two used in sequence. The specimens were viewed in a scanning electron microscope and scored for the presence or absence of a smear layer at levels <1 mm, 5 mm and 10 mm from the apical seat. The most effective combination, as tested, was hand instrumentation to file size 40 with lml EDTAC irrigation between each instrument size, supplemented by intermittent flush irrigation with EDTAC with ultrasound then 4% sodium hypochlorite with ultrasound. This technique left a minimum smear layer restricted to the apical seat. Other combinations of instrumentation and irrigation were not consistent in their effectiveness.
The influence of ultrasound in removing intraradicular posts
Authors: BERBERT* A. , FILHO M. T. , UENO A. H. , BRAMANTE C. M. , ISHIKIRIAMA A.
Published: September 2007

Thirty single‐rooted teeth were prepared to receive cast posts. After cementation of the post the teeth were divided into three groups. Group I did not receive any treatment, whereas the posts in groups II and III were treated with an ultrasonic device, for 2 min and 5 min, respectively. The force required for post removal was determined using a universal test machine. No statistical differences (P>0.05) were found between the groups where ultrasound had been used.

Significantly reduced forces were necessary to remove the posts from group II and III, compared with group I which did not receive ultrasonic treatment (P<0.05).
Assessing the shape of root canals: an in vitro method using microradiography
Authors: THOMPSON S. A. , AL‐OMARI* M. A. O. , DUMMER P. M. H.
Published: September 2007

The aim of this paper is to describe an in vitro method which provides clear and accurate details of root canal shape. The method utilizes the technique of contact microradiography to produce high resolution, two‐dimensional, real‐size images of canals in a longitudinal plane. Specimens can be accurately rotated through 90° allowing images to be produced in a bucco‐lingual and mesio‐distal direction. The method is simple, relatively rapid and can process large numbers of teeth without the need for complicated and expensive mounting blocks or film holders. The technique can be used to produce pre‐ and post‐operative images of canal shape which can be superimposed to delineate the dentine removed during canal preparation. The method is thus suitable for the evaluation of the shaping ability of endodontic instruments and preparation techniques.
Root canal instruments for manual use: cutting efficiency and instrumentation of curved canals
Authors: TEPEL J. , SCHÄFER E. , HOPPE W.
Published: September 2007

The cutting efficiency of different endodontic hand instruments and the effects of instrumentation on curved canal shape were investigated under standardized experimental conditions using an automatic testing device.

Cutting efficiency in rotary motion was assessed by determination of the maximum penetration depth of the instruments into a cylindrical canal in a special resin block (size 25 and size 35 instruments). Changes in canal shape were determined by instrumentation of standardized canals (42° curvature) incrementally from size 15 to size 35.

Except in the case of one instrument, size 35, in both sizes tested flexible instruments reached significantly (P < 0.05) greater maximum penetration depths than conventional reamers or K‐files. Changes in the canal shape differed significantly between the different instruments in 13 of the 14 measuring points. Drastic undesirable changes in the canal shape (e.g. straightening or zip and elbow) occurred after instrumentation with reamers and K‐files, but these changes were less noticeable after instrumentation with flexible instruments with conventional tips. After instrumentation with flexible instruments with modified tips there were few undesirable changes in shape.

The conclusion could be drawn that flexible instruments, especially those with modified tips, were clearly superior to conventional reamers and K‐files with regard to cutting efficiency and instrumentation of curved canals.
In vitro radiographic representation of the extent of voids within obturated root canals
Authors: YOUNGSON C. C. , NATTRESS B. R. , MANOGUE M. , SPEIRS A. F.
Published: September 2007

The aim of this study was to determine whether radiographs provide an accurate representation of the degree of root canal obturation following a cold lateral condensation technique. A total of 40 extracted single‐rooted lower premolar teeth were prepared using either a standardized step‐back technique or an ultrasonic device by one of two operators. The four groups, each of 10 teeth were obturated using lateral condensation by a third operator. To assess apical leakage the obturated teeth were coated with nail varnish to within 2 mm of the apex and immersed in methylene blue for 48 h. The teeth were then radiographed in bucco‐lingual and mesio‐distal planes prior to subsequent sectioning in a bucco‐lingual plane. Sections and radiographs were analysed using an image analysis apparatus to determine the proportion of root canal occupied by gutta‐percha, void and/or sealer. Mean percentages of void calculated from the bucco‐lingual radiographs, mesio‐distal radiographs and tooth sections were 4.14%, 5.98% and 4.98%, respectively. Statistical analysis showed no significant differences between the radiographic views and the tooth sections (P > 0.05). Both planes of radiograph accurately represented the proportion of void when compared with the tooth section.
A survey of general dental practitioners’ approach to the restoration of root‐filled teeth
Authors: HUSSEY D. L. , KILLOUGH S. A.
Published: September 2007

This paper reports the findings of a survey of a group of general dental practitioners (GDPs) from one region of the United Kingdom. The practitioners were asked to complete a questionnaire investigating their approach to the restoration of root‐filled teeth. A high response rate was achieved and the replies indicated that most practitioners restore teeth within 1 month of completing the root filling. Nonprecious cast alloys cores were popular as was amalgam for core build‐ups. Most practitioners opted for a post which was two‐thirds the length of the root and zinc phosphate was the most popular luting material. Almost one‐quarter of respondents believed that a root is strengthened by a post retained restoration and a similar number have never attended a postgraduate meeting on the subject of the restoration of root‐filled teeth.
The fate and the role of bacteria left in root dentinal tubules
Authors: PETERS L. B. , WESSELINK P. R. , MOORER W. R.
Published: September 2007

In this article the question of the relevance and consequences of bacteria remaining in the tubules of root dentine after cleaning and shaping of the root canal space is addressed. A second aim is to discuss the necessity of clinical measures taken to eradicate those bacteria that are presumed to survive there. The available clinical and experimental evidence supports the use of antibacterial dressings in cases where the root canal space remains temporarily unobturated after removal of necrotic and infected pulp tissue. There is no evidence, however, that special measures should be taken to kill the bacteria in the dentinal tubules. Should time permit, a sound obturation technique immediately following the cleaning, shaping and disinfection phases allows the remaining bacteria in the tubules to be either inactivated or prevented from repopulating the (former) canal space. In the vast majority of cases, those bacteria appear not to jeopardize the successful outcome of root canal treatment.
The Influence of ultrasound in removing intraradicular posts
Authors: BERBERT* A. , FILHO M. T. , UENO A. H. , BRAMANTE C. M. , ISHIKIRIAMA A.
Published: September 2007

Thirty single‐rooted teeth were prepared to receive cast posts. After cementation of the post the teeth were divided into three groups. Group I did not receive any treatment, whereas the posts in groups II and III were treated with an ultrasonic device, for 2 min and 5 min, respectively. The force required for post removal was determined using a universal test machine. No statistical differences (P>0.05) were found between the groups where ultrasound had been used.

Significantly reduced forces were necessary to remove the posts from group II and III, compared with group I which did not receive ultrasonic treatment (P<0.05).
Simulated resorptive defects and open apices using bovine and human teeth as teaching models
Authors: OSBORNE G. E. , CHANDLER N. P.
Published: September 2007

An ‘open apex’ model for teaching obturation tech‐niques in a very wide root canal has been developed using bovine deciduous incisors which are soon to be exfoliated. Extracted human teeth may also be modified in a variety of ways to simulate resorptive defects. Both may be combined with existing models to allow use in a phantom head or be mounted in materials to mimic the radiographic appearance of bone.
Changes in endodontic status 1973–1993 among 35‐year‐olds in Oslo, Norway
Authors: ERIKSEN H. M. , BERSET G. P. , HANSEN B. F. , BJERTNESS E.
Published: September 2007

Epidemiological investigations from Scandinavia have documented high prevalence of apical periodontitis and inferior quality and results of endodontic treatment performed in general practice. The present investigation is part of a 20‐year follow‐up study on oral health in 35‐year‐old Oslo citizens focusing on endodontic con‐ditions. The results indicate reduced prevalence of apical periodontitis and statistically significant improvement in endodontic status compared with results from a similar study performed in 1984.
Light and SEM observation of internal root resorption of a traumatized permanent central incisor
Authors: AL‐NAZHAN S. A. , SPANGBERG L. W.
Published: September 2007

A clinical case report is presented which illustrates internal root resorption of a traumatized tooth. Light and scanning electron microscope were used to further examine the defect. An explanation of the morphological structure of the resorption is discussed.
Multidisciplinary aspects of root resection failure: a case report
Authors: LEONARD J. E. , GUTMANN J. L.
Published: September 2007

Creative approaches to tooth maintenance often include tooth resection and retention of one or more of the roots. Although this procedure is reasonably successful, failure of supportive endodontic, periodontic, and restorative management of the retained roots can jeopardize a successful outcome. The following is a case report evaluating multiple aetiologies contributing to root resection failure.
An in vitro comparison of 10 radiographic methods for working length estimation
Authors: RUSHTON V. E. , SHEARER A. C. , HORNER K. , CZAJKA J.
Published: September 2007

The aim of this in vitro study was to assess the efficacy of 10 currently available methods of producing radiographic images, two conventional and eight rapid, in working length estimation. Thirty extracted teeth comprising 42 root canals were mounted in blocks of poly(methylmethacrylate) and access cavities prepared. A size 15 Hedstrom file was inserted into each root canal and sealed into position. Each tooth was imaged by 10 methods: combinations of conventional (D− and E− speed) film processed with conventional manual chemistry or two proprietary brands of rapid processing chemistry (Westone Rapid Dental and Kodak ‘Rapid Access’), Super X30 packet processed film, Hanshin Hi‐Fi and Nix NF45‐100 films processed using their respective manufacturers' monobath solutions, and the Sens‐A‐Ray digital X‐ray system. Comparisons of length of file visible were made between the D‐speed films (conventionally processed using Kodak chemistry) and the nine other radiographic methods. No significant differences in percentage length of file seen were found between D‐speed film processed with conventional chemistry and E‐speed film processed with the same chemistry or between D‐speed film processed with conventional chemistry and six of the rapid imaging systems studied. The percentage length of the file visible was significantly less for Sens‐A‐Ray (P=0.02) and for Nix NF45‐100 film (P<0.005)when compared with D‐speed film processed with conventional chemistry. This difference in file length is probably not of clinical importance for the Sens‐A‐Ray images but may be so for the Nix images.
Isolation and characterization of the proteoglycans synthesized by adult human pulp fibroblasts in vitro
Authors: BARTOLD P. M. , MOULE A. J. , LI H. , RIGBY P.
Published: September 2007

The proteoglycans synthesized by fibroblasts derived from healthy human adult dental pulps have been isolated and characterized on the basis of their glycosaminoglycan content, molecular size and charge. The proteoglycans were identified by their labelling with [35S] sulphate and susceptibility to digestion by papain. The sulphated glycosaminoglycans associated with the proteoglycans were identified following specific enzymatic and chemical degradations as chondroitin sulphate, dermatan sulphate and heparan sulphate. Dermatan sulphate and chondroitin sulphate were identified as the major glycosaminoglycans secreted into the medium, whereas chrondroitin sulphate and heparan sulphate were the principal glycosaminoglycans associated with the cell layers. The proteoglycans could be fractionated on the basis of their charge and size into a number of heterogeneous pools. The principal proteoglycans isolated were small and contained either chondroitin sulphate or dermatan sulphate and most likely correspond to decorin and biglycan. Other molecules with features similar to versican and syndecan were also identified.
Effect of dentine surface treatment on leakage of root fillings with a glass ionomer sealer
Authors: HOLLAND R. , SAKASHITA M. S. , MURATA S. S. , JUNIOR E. D.
Published: September 2007

The purpose of this study was to observe the quality of seal of the glass ionomer cement, Ketac‐Endo, after treatment of the root canal wall. The root canals of 140 extracted human teeth were prepared biomechanically. The root canals were treated with either EDTA or received an intracanal dressing of calcium hydroxide or camphorated paramonochlorphenol. The root canals were filled by the lateral condensation technique with gutta‐percha points and the sealer Ketac‐Endo, or zinc oxide‐eugenol cement or Sealapex. The teeth were placed into a 2% methylene blue dye solution inside a flask, which was attached to a vacuum pump. Leakage was measured linearly. Sealapex exhibited significantly less leakage than Ketac‐Endo or zinc oxide‐eugenol cement (P < 0.01). The use of EDTA and intermediary dressings reduced significantly (P <0.01) the leakage observed with the zinc oxide‐eugenol sealer and Ketac‐Endo.
Marginal leakage of Gallium Alloy root‐end fillings: an in‐vitro assessment
Authors: WHITWORTH J. M. , KHAN A. Q.
Published: September 2007

The sealing ability of amalgam and Gallium Alloy Gallium Filling (GF) root‐end fillings was evaluated in vitro using a highly uniform collection of sheep incisor roots. Following ultrasonic canal debridement and orthograde obturation with gutta‐percha and sealer, root‐end cavities were prepared in 100 roots and filled with amalgam (50 teeth) or Gallium Alloy GF (50 teeth). Twenty‐five teeth from each group were subjected to immediate dye leakage assessment under vacuum conditions with methylene blue dye (2%), pH 7. Linear dye penetration was measured following longitudinal splitting. The other 25 teeth from each group were incubated in Ringer's solution for 12 weeks before leakage assessment by the same method. Control teeth were included in each component of the study.

Mean linear dye penetration was: amalgam—5.17mm at baseline, 2.33mm after 12 week's incubation; Gallium Alloy GF—2.21mm at baseline, 1.41mm after 12 week's incubation. The apical marginal seal of both materials improved significantly following storage in Ringer's solution (P < 0.001). Gallium Alloy GF provided a better apical seal than amalgam, both at baseline and following storage (P < 0.001). Subjective evaluation of the general handling characteristics of Gallium Alloy GF revealed that it was a more difficult material to manipulate than amalgam, largely because of its wetting ability and consequent adhesion to dental instruments.
Endodontically treated teeth and periapical findings in the elderly
Authors: SOIKKONEN K. T.
Published: September 2007

The radiographic quality of root‐canal fillings, the prevalence of periapical findings and their associations with gender and age and were investigated in 133 dentate old people living at home (45 males and 88 females, aged 76, 81, and 86 years and who had endodontically treated teeth or periapical lesions.

Sixteen per cent of the endodontically treated teeth (n= 507) exhibited periapical lesions, compared with 4% for the teeth not endodontically treated (P < 0.0001) (χ2 test). Lesions were least prevalent in association with radiographically adequate root canal fillings (10%), and most prevalent in teeth with root canal post perforation (100%). Overfilled root canals and multi‐rooted teeth with one or more unfilled roots also showed a high percentage of lesions (19% and 22%, respectively). Men had more periapical lesions than women in endodontically treated teeth (P < 0.0001, Mann‐Whitney U‐test), a finding contrary to previous studies in younger subjects. There were no other statistically significant differences between the sexes or age groups, although the percentage of root‐filled teeth increased with age.
The effect of retrograde cavity design on microleakage of amalgam fillings
Authors: GULABIVALA K. , SAYED A. A. , WILSON M.
Published: September 2007

A phantom head model was modified to simulate as closely as possible the limited access encountered during periapical surgery on maxillary anterior teeth. Extracted human maxillary anterior and mandibular canine teeth were placed in this model in a standardized position for root resection, retrograde cavity preparation and filling with amalgam. Three different designs of retrograde cavities were evaluated: the conventional class 1 cavity, the slot cavity and a previously unreported approach, the funnel cavity.

Upon completion of the retrograde filling, the teeth were removed from the model and subjected to microleakage tests by placing radiolabelled lipopolysaccharide in a reservoir created coronal to the retrograde fillings. Leakage was quantified by measurement of radioactivity in scintillation counter.

It was found that the retrograde fillings in the funnel cavity leaked significantly less than those in the other two cavity designs. There was no statistically significant difference in leakage between the conventional class 1 and the slot cavities up to the thirtieth day 30.
In‐vitro measurement of apieally extruded irrigant in primary molars
Authors: WILLIAMS C. E. C. S. , REID J. S. , SHARKEY S. W. , SAUNDERS W. P.
Published: September 2007

This study investigated the weights of irrigant extruded apically through extracted primary molar teeth. The aim was to compare the weight of canal irrigant (isotonic sodium chloride solution) extruded through the root canal using either a syringe fitted with a 27‐gauge needle or an endosonic unit. Root canals were divided randomly into five groups of 15 discrete canals. The area of each apical foramen was recorded prior to the use of the irrigant. For each irrigation technique the maximum depth of penetration of the needle tip/file was either 2–3 mm or 6–7 mm from the apical foramen. In four groups the crowns of the teeth were in a mandibular position, in the fifth group the teeth were inverted to simulate maxillary teeth. The results showed that irrigant was extruded using both methods. There was significantly less extrusion of irrigant when the endosonic unit was used (P < 0.01). There was no statistically significant relationship between foramen area and amount of extruded irrigant (P > 0.05). There was no significant extrusion of irrigant in teeth with closed apices when either of the two methods was used (P>0.05).
Long‐term evaluation of endodontic and periodontal treatment
Authors: JAOUI L. , MACHTOU P. , OUHAYOUN J.P.
Published: September 2007

One hundred and ninety‐five teeth in 35 patients with periodontitis who had received both endodontic and periodontal treatment were evaluated 9 years after endodontic treatment and 8 years after periodntal treatment. Some 91.4% of cases were well maintained and 8.6% showed a deterioration in their periodontal condition. Twelve of the 195 teeth with endodontic treatment were lost, eight for periodontal codition. Twelve of the 195 teeth with endodontic treatment were lost, eight for periodontal reasons, three as a result of fracture and one because of caries, and the periodontal condition of 10 teeth had worsened. An apical lesion formed on one tooth. The results indicate that the risk of endodontic failure in this group of 195 teeth is very low, and that there is little risk of tooth loss for periodontal reasons, provided that the patients receive suppportive periodontal treatment.
Clinical diagnosis of internal resorption: an exception to the rule
Authors: GULABIVALA K. , SEARSON L. J.
Published: September 2007

This paper describes a case in which the radiographic appearance of a resorptive lesion in a mandibular incisor tooth posed difficulty in the diagnosis of its origin. The lesion did not conform to the normally accepted criteria for diagnosis of internal resorption. Clinical examination did not support the diagnosis of external cervical resorption. Serial histological section of the extracted tooth subsequently confirmed the diagnosis of internal resorption. The criteria for differential diagnosis of resorptive lesions with smooth outlines in the cervical regions of teeth are discussed together with the rationale for their management.
Factors associated with endodontic flare‐ups: a prospective study
Authors: IMURA N. , ZUOLO M.L.
Published: September 2007

The purpose of this prospective study was to assess the incidence of flare‐ups (a severe problem requiring an unscheduled visit and treatment) among patients who received endodontic treatment by the two authors in their respective practices during a period of one year, and also to examine the correlation with pre‐operative and operative variables. The results showed an incidence of 1.58% for flare‐ups from 1012 endodontically treated teeth. Statistical analysis using the chisquare test (P<0.05) indicated that flare‐ups were found to be positively correlated with multiple appointments, retreatment cases, periradicular pain prior to treatment, presence of radiolucent lesions, and patients taking analgesic or anti‐inflammatory drugs. In contrast, there was no correlation between flare‐up, and age, sex, different arch/tooth groups and the status of the pulp.
The adaptation of mechanically softened gutta‐percha to the canal walls in the presence or absence of smear layer: a scanning electron microscopic study
Authors: PALLARÉS A. , FAUS V. , GLICKMAN G. N.
Published: September 2007

The objective of this study was to compare the adaptation of mechanically softened gutta‐percha to the root canal wall in the presence and absence of smear layer. The root canals of 20 freshly extracted human maxillary incisors were cleaned and shaped. Prior to obturation, 10 root canals were irrigated with 20 ml of 50% citric acid followed by 20 ml of 5.25% sodium hypochlorite. All canals were obturated with mechanical compaction of gutta‐percha and AH‐26 sealer. After 72h, each tooth was fractured in half. Scanning electron microscopy demonstrated that the sealer had formed a continuous layer in contact with the canal walls, becoming progressively thinner towards the apex. The sealer pentrated into the dentinal tubules along with projections of gutta‐percha only in those teeth without smear layer.
A computerized method for the evaluation of root canal morphology
Authors: BLAŠKOVIĆ‐ŠUBAT V. , SMOJVER I. , MARIČIĆ B. , ŠUTALO J.
Published: September 2007

The objective of this research was to develop a technique that would allow three‐dimensional imaging of root canals utilizing computer image processing. Ten single‐rooted permanent human teeth with mature apices were analysed. The teeth were decoronated and fixed on boards with the long axis of the root perpendicular to the board. The cross‐sectioning started at the root apex and continued in the coronal direction, roughly perpendicular to the long axis of the root. The samples were divided into two groups. The first five samples were sectioned 15 times, each section being 0.5‐mm thick, in order to obtain the three‐dimensional reconstruction of the root and the root canal. The second group of five samples served for the graphical reconstruction of the apical portion of the root canal. The root apex of each sample was cross‐sectioned 19 times and each section was 0.2‐mm thick. After each section, the root canal contour was defined utilizing the calibrated net with coordinate system in the ocular of the stereo‐microscope. The coordinates of the root canal cross‐section contour thus determined, together with the value of the thickness of each cut, were relevant input data for the reconstruction of the root canal cross‐sections, longitudinal sections and for the final three‐dimensional rebuild of the root and the root canal model. This technique appears to be highly accurate in determining the anatomy of the root canal system and may also be applied in other fields of dental research.
Apical and coronal seal of roots obturated with a dentine bonding agent and resin
Authors: LEONARD J. E. , GUTMANN J. L. , GUO I. Y.
Published: September 2007

The efficacy of sealing root canal systems with a dentine bonding agent and resin cement was compared with that of a glass ionomer sealer. Scanning electron microscopic examination of the bonding agent‐dentine interface was also performed. The root canals of 50 single rooted teeth with mature apices were prepared chemo‐mechanically and the smear layer removed with 17% REDTA and 5.25% NaOCl. Specimens were divided into two groups of 24 teeth each. One group had the dentine conditioned with a 10:3 citric acid‐ferric chloride solution and obturated with the dentine bonding agent and resin, radiopaque C & B Metabond. The other group was obturated with the glass ionomer sealer, Ketac‐Endo and a single cone of gutta‐percha. After immersion in Indian ink for 90 h, the teeth were cleared and the quality of the apical and coronal seal was assessed using India ink dye penetration. There was a significantly better seal in both the apical and coronal directions when using the dentine bonding agent and resin obturation material. Scanning electron microscopic examination of the demineralized dentine and the C & B Metabond interface revealed the presence of the characteristic hybrid layer along with microtags of resin penetrating deep into the dentine tubules.
An in‐vitro study of smear layer removal and microbial leakage along root‐canal fillings
Authors: BEHREND G. D. , CUTLER C. W. , GUTMANN J. L.
Published: September 2007

The objective of this study was to determine the effect of removal of the smear layer on canal obturation as measured by penetration of bacteria from a coronal direction. Fifty‐four extracted human teeth were decoronated and instrumented in a uniform manner. Following instrumentation the root canals of 20 teeth were rinsed with 17% EDTA and 5.25% NaOCl to remove the smear layer before obturation. A second group of 20 teeth were flushed with NaOCl alone. The teeth of both groups were obturated with ThermafilTM plastic carriers and Roth's sealer. The root canals of another 10 teeth, five rinsed with EDTA and five without, were obturated with ThermafilTM without sealer. Two teeth serving as positive controls were instrumented but not obturated, while another set of two were sealed coronally and apically to serve as negative controls. The root surface of each tooth was sealed with nail varnish. A small chamber was thoroughly sealed around the coronal aspect of each tooth so that bacteria placed therein could move only through the obturated canal space. Each tooth was placed in a test tube containing sterile trypticase soy broth (TSB). An inoculum of Proteus vulgaris in TSB was placed in each coronal chamber at five day intervals and daily observations were made for bacterial growth in the apical reservoir for 21 days. Both positive control teeth showed bacterial penetration after 24 h. Neither of the two negative control teeth demonstrated penetration for the duration of the study. The frequency of bacterial penetration through teeth obturated with intact smear layer (70%) was significantly greater than that of teeth from which the smear layer had been removed (30%) P< 0.05. All but one tooth obturated without sealer exhibited bacterial penetration, irrespective of the presence or absence of smear layer. Removal of the smear layer enhanced sealability as evidenced by increased resistance to bacterial penetration.