bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diminished leakage along root canals filled with gutta‐percha without sealer over time: a laboratory study
Authors: Wu M. ‐K. , Fan B. , Wesselink P. R. 
Published: March 2003

Aim  The aim of this study was to investigate the long‐term seal of gutta‐percha (GP) without sealer.Methodology Extracted human maxillary central incisors were prepared and obturated using heat‐ or chloroform‐softened GP only, or GP in combination with a root canal sealer. Leakage along root fillings was measured at 48 h and after a period of 6 months using a fluid transport model.Results  At 48 h the GP‐filled roots without sealer leaked more than the control roots filled with GP and sealer (P <0.0001). At 6 months a significant reduction in leakage was found in the GP‐only groups (P< 0.05 for both heat‐ and chloroform‐softened GP). After 6 months, roots filled by vertical condensation of GP‐only had similar leakage as vertically condensed GP with a sealer (P >0.05).Conclusions  The long‐term seal of root fillings is affected by the volume change of both GP and sealer. Leakage reduction due to expansion of GP may compensate to a certain extent for leakage that may occur from sealer dissolution.
Comparison of cold lateral condensation and a warm multiphase gutta‐percha technique for obturating curved root canals
Authors: Gilhooly R. M. P. , Hayes S. J. , Bryant S. T. , Dummer P. M. H. 
Published: March 2003

AbstractAimThe aim of this project was to evaluate and compare the radiographic quality and sealability of root fillings in extracted human teeth using lateral condensation of gutta‐percha or multiphase gutta‐percha obturation (Alphaseal).MethodologyA total of 108 freshly extracted human, mature single‐rooted teeth were divided into two identical groups of 54 teeth on the basis of root canal shape. The canals were prepared to a minimum 0.055 taper and enlarged to size 35 at the apex. All root canals were flushed with 17% EDTA solution and 2.5% NaOCl to remove the dentinal smear layer. The canals of one group were obturated using cold lateral condensation of gutta‐percha and the canals of the other group were filled using a warm multiphase gutta‐percha obturation technique. The extrusion of sealer and/or gutta‐percha through the apex of the teeth was recorded using a simple yes/no scheme. The sealability of each technique was assessed by a dye penetration method. The radiographic quality of obturation was determined for each canal using a four‐point scale.ResultsRoot canals filled by multiphase obturation had significantly more extrusion of sealer (P < 0.001) and gutta‐percha (P < 0.001) than canals filled by lateral condensation. Canals filled by multiphase gutta‐percha obturation had significantly less apical dye leakage than those obturated by lateral condensation (P < 0.05). Lateral condensation achieved significantly better scores for radiographic quality than multiphase obturation from the bucco‐lingual view (P < 0.01).ConclusionsUnder laboratory conditions multiphase gutta‐percha had better sealability but poorer radiographic quality than lateral condensation.
An overview of nickel–titanium alloys used in dentistry
Authors: Thompson S. A. 
Published: March 2003

AbstractThompson SA.An overview of nickel–titanium alloys used in dentistry. International Endodontic Journal, 33, 297–310, 2000.Literature reviewThe nickel–titanium alloy Nitinol has been used in the manufacture of endodontic instruments in recent years. Nitinol alloys have greater strength and a lower modulus of elasticity compared with stainless steel alloys. The super‐elastic behaviour of Nitinol wires means that on unloading they return to their original shape following deformation. These properties are of interest in endodontology as they allow construction of root canal instruments that utilize these favourable characteristics to provide an advantage when preparing curved canals. This review aims to provide an overview of Nitinol alloys used in dentistry in order for its unique characteristics to be appreciated.
The structure of dentine in the apical region of human teeth
Authors: Mjör I. A. , Smith M. R. , Ferrari M. , Mannocci F. 
Published: March 2003

AbstractAimTo study the structure of the apical region of human teeth with emphasis on dentinal tubules and their branches.MethodologyThis descriptive histological study employed demineralized stained sections for light microscopy, demineralized unstained sections for scanning electron microscopy, and undemineralized, acid‐etched specimens for confocal tandem scanning microscopy.ResultsThe apical portion of human teeth showed marked variations in structure, including accessory root canals, areas of resorption and repaired resorptions, occasional attached, embedded and free pulp stones, varied amounts of irregular secondary dentine, and even cementum‐like tissue lining the apical root canal wall. The apex often deviated from the long axis of the root canal. Primary dentinal tubules were irregular in direction and density. Some areas were devoid of tubules.ConclusionsThe irregular and variable structure of the apical region of human teeth represent special challenges during endodontic therapy. Obturation techniques based on the penetration of adhesives into dentinal tubules are unlikely to be successful and adhesive techniques must depend on impregnation of a hybrid layer.
In vitro antimicrobial activity of several concentrations of sodium hypochlorite and chlorhexidine gluconate in the elimination of Enterococcus faecalis
Authors: Gomes B. P. F. A. , Ferraz C. C. R. , M. E. Vianna , Berber V. B. , Teixeira F. B. , Souza‐Filho F. J. 
Published: March 2003

AbstractAimThe aim of this study was to assess, in vitro, the effectiveness of several concentrations of NaOCl (0.5%, 1%, 2.5%, 4% and 5.25%) and two forms of chlorhexidine gluconate (gel and liquid) in three concentrations (0.2%, 1% and 2%) in the elimination of E. faecalis.MethodologyA broth dilution test using 24‐well cell culture plates was performed and the time taken for the irrigants to kill bacterial cells was recorded. Isolated 24 h colonies of pure cultures of E. faecalis grown on 10% sheep blood plus Brain Heart Infusion (BHI) agar plates were suspended in sterile 0.85% NaCl solution. The cell suspension was adjusted spectrophotometrically to match the turbidity of a McFarland 0.5 scale. One mL of each tested substance was placed on the bottom of wells of 24‐well cell culture plates (Corning, NY), including the control group (sterile saline). Six wells were used for each time period and irrigant concentration. Two mL of the bacterial suspension were ultrasonically mixed for 10 s with the irrigants and placed in contact with them for 10, 30, and 45 s; 1, 3, 5, 10, 20, and 30 min; and 1 and 2 h. After each period of time, 1 mL from each well was transferred to tubes containing 2 mL of freshly prepared BHI + neutralizers in order to prevent a residual action of the irrigants. All tubes were incubated at 37°C for 7 days. The tubes considered to have positive growth were those which presented medium turbidity during the incubation period. Data were analysed statistically by the Kruskal–Wallis test, with the level of significance set at P < 0.05.ResultsAll irrigants were effective in killing E. faecalis, but at different times. Chlorhexidine in the liquid form at all concentrations tested (0.2%, 1% and 2%) and NaOCl (5.25%) were the most effective irrigants. However, the time required by 0.2% chlorhexidine liquid and 2% chlorhexidine gel to promote negative cultures was only 30 s and 1 min, respectively.ConclusionsEven though all tested irrigants possessed antibacterial activity, the time required to eliminate E. faecalis depended on the concentration and type of irrigant used.
Efficacy of chemical sterilization and storage conditions of gutta‐percha cones
Authors: Da Motta P. G. , De Figueiredo C. B. O. , Maltos S. M. M. , Nicoli J. R. , Ribeiro Sobrinho A. P. , Maltos K. L. M. , Carvalhais H. P. M. 
Published: March 2003

AbstractAimThe objective of the present study was to assess the efficacy of 2.5% sodium hypochlorite and 2.2% glutaraldehyde (‘Cidex’) as sterilizing agents for gutta‐percha cones. The efficacy of storage of gutta‐percha cones in the presence or absence of paraformaldehyde was also evaluated.MethodologyGutta‐percha cones artificially contaminated with a suspension of Bacillus stearothermophilus (ATCC/7953) were treated with either 2.2% glutaraldehyde for 10, 15, 30 and 60 min and 10 and 12 h, or 2.5% sodium hypochlorite for 5, 10 and 15 min. The cones were then incubated in thioglycollate medium for the determination of microbial growth. In parallel, additional sterile gutta‐percha cones were stored in sealed containers with or without paraformaldehyde tablets for 30 days. The containers were opened 30 min a day and exposed to the environment of a functioning dental clinic. Twelve cones were removed weekly from the containers to determine whether contamination had occurred.ResultsThe results showed that 2.5% sodium hypochlorite was effective after 5, 10 and 15 min, whereas 10 and 12 h contact with 2.2% glutaraldehyde was necessary to obtain sterilization. There was no contamination of the gutta‐percha cones when stored with or without paraformaldehyde.ConclusionsSodium hypochlorite (2.5%) and 2.2% glutaraldehyde (‘Cidex’) proved to be effective as sterilizing agents for gutta‐percha cones, with sodium hypochlorite requiring shorter periods of use. No difference was observed between the two methods of cone storage.
A reconstructed computerized tomographic comparison of Ni–Ti rotary GT™ files versus traditional instruments in canals shaped by novice operators
Authors: Gluskin A. H. , Brown D. C. , Buchanan L. S. 
Published: March 2003

AbstractAimThe aim of this study was to compare the effects of preparation with conventional stainless steel Flexofiles® and Gates Glidden burs versus nickel–titanium GT™ rotary files in the shaping of mesial root canals of extracted mandibular molars.MethodologyA total of 54 canals from 27 mesial roots of mandibular molar teeth were prepared using one of two methods by novice dental students. One canal in each root was prepared by a crown‐down approach, utilizing stainless steel Flexofiles® and Gates Glidden burs. The other canal was prepared using nickel–titanium GT™ rotary files in a crown‐down fashion as recommended by the manufacturer. Preoperative CT scans of each root were recorded and 50 canal specimens were available for postoperative comparisons. Following canal shaping, postoperative scans were superimposed on the original images. Changes in canal area, canal transportation and thickness of remaining root structure at strategic levels of the root were analyzed. The time taken for each method was also noted.ResultsAt the coronal and mid‐root coronal one‐third sections, the rotary GT™ files produced a significantly smaller postoperative canal area (P < 0.05). In the mid‐root sections there was significantly less transportation of the root canal toward the furcation, and less thinning of the root structure with GT™ files compared to the stainless steel files (P < 0.05). Overall, there was greater conservation of structure coronally and more adequate shape in the mid‐root level. The GT™ rotary technique was significantly faster than the stainless steel hand‐held file technique (P < 0.0001). Two GT™ instruments fractured during the study.ConclusionsUnder the conditions of this study, novice dental students were able to prepare curved root canals with Ni–Ti GT™ rotary files with less transportation and greater conservation of tooth structure, compared to canals prepared with hand instruments. The rotary technique was significantly faster.
A comparison of the quality of root canal treatment in two Danish subpopulations examined 1974–75 and 1997–98
Authors: Kirkevang L‐L. , Hörsted‐Bindslev P. , Ørstavik D. , Wenzel A. 
Published: March 2003

AbstractAimThe aim of this study was to compare the quality of root canal treatment in two Danish subpopulations.MethodologyGroup 1 (358 patients) was examined 1974–75 and group 2 (244 patients) 1997–98. All patients were more than 20 years old. All had undergone a full‐mouth radiographic survey. In root‐filled teeth the following parameters were assessed: the quality of the coronal restoration or crown, the lateral seal of the root filling, the length of the root filling, and the periapical status. Chi‐squared tests were used for the evaluation of differences between the groups.ResultsIn group 1 there were 975 endodontically treated teeth, in group 2 there were 753. In group 1 the majority of root‐filled teeth were premolars, in group 2 the majority were molars (P < 0.001). The quality of coronal restorations (P = 0.35) and crowns (P = 0.68) did not differ significantly between the groups. In group 2 more teeth had adequately sealed root canals (P < 0.001) and adequate length of root filling (P < 0.001). More root‐filled molar teeth had apical periodontitis (AP) than root‐filled premolar and anterior teeth (P < 0.001).ConclusionsWhilst the technical quality of endodontic treatment had improved during the last 24 years, basic differences between the populations prevented assessment of the impact of this change on disease frequencies. The study indicates that great care should be taken when comparing different patient populations, in particular more emphasis should be placed on the selection and description of study groups.
Endodontic treatment of teeth associated with a large periapical lesion
Authors: Öztan M. D. 
Published: March 2003

AbstractAim To report the healing of a large periapical lesion following non‐surgical root canal treatment.Summary A 12‐year‐old male with a large periapical lesion around the apices of his mandibular incisors is described. The lesion formed after trauma to the mandibular anterior teeth 5 years previously. During root canal treatment, chlorhexidine gluconate was used for irrigation, and calcium hydroxide was used both for the intracanal dressing and as a base of the root canal sealer. Periapical healing was observed 3 months after obturation and continued at the 12‐month review.Key learning points

Root canal treatment, including the use of chlorhexidine gluconate and calcium hydroxide for infection control, led to substantial healing of a large periapical lesion.
This report confirms that large periapical lesions can respond favourably to non‐surgical treatment.
A survey of methods used for post removal in specialist endodontic practice
Authors: Castrisos T. , Abbott P. V. 
Published: March 2003

AbstractAim The aims of this study were to determine the attitudes of endodontists toward the risk of root fracture when removing posts and to determine which methods they commonly used to remove posts from root‐filled teeth.Methodology A survey was sent to all 74 members of the Australian and New Zealand Academy of Endodontists. The survey was divided into three parts to gather information concerning root canal retreatment performed in specialist endodontic practice, attitudes about the risk of root fracture when removing posts and the methods used to remove different post systems.Results Responses were received from 62 (84%) of the Academy members. When a post was present in a tooth that required root canal retreatment, 66% of the endodontists preferred to remove the post, whilst 27% considered either post removal or periapical surgery. Forty‐five per cent reported that a root fracture had occurred during post removal, but this represented less than 0.002% of the estimated number of posts removed by all respondents. Ultrasonic vibration was the most common method used to remove posts, although post removal devices were used more often in anterior teeth; the Eggler post remover was the most commonly used device.Conclusions Most endodontists preferred to remove posts rather than perform periapical surgery. Few root fractures were reported. Ultrasonic vibration was the most common method used to remove posts from all tooth types, with the Eggler post remover used most commonly for posts in anterior teeth.
Penetration of propylene glycol into dentine
Authors: Cruz E. V. , Kota K. , Huque J. , Iwaku M. , Hoshino E. 
Published: March 2003

AbstractCruz EV, Kota K, Huque J, Iwaku M, Hoshino E. Penetration of propylene glycol into dentine. International Endodontic Journal, 35, 330–336, 2002.Aim This study aimed to evaluate penetration of propylene glycol into root dentine.Methodology Safranin O in propylene glycol and in distilled water were introduced into root canals with and without artificial smear layer. Dye diffusion through dentinal tubules was determined spectrophotometrically. The time required for dye to exit through the apical foramen using propylene glycol and distilled water as vehicles was also determined. The extent and areas of dye penetration on the split surfaces of roots were assessed using Adobe Photoshop and NIH Image Software.Results Propylene glycol allowed dye to exit faster through the apical foramen. The area and depth of dye penetration with propylene glycol was significantly greater than with distilled water (P < 0.0001). Smear layer significantly delayed the penetration of dye.Conclusion Propylene glycol delivered dye through the root canal system rapidly and more effectively indicating its potential use in delivering intracanal medicaments.
Localized alveolar bone necrosis following the use of an arsenical paste: a case report
Authors: Özmeriç N. 
Published: March 2003

AbstractAim To describe some toxic effects of arsenic trioxide in the mouth, to condemn its continued use, and present a case in which a tooth was preserved despite significant bony destruction.Summary A case is presented in which severe alveolar bone necrosis resulted from leakage of an arsenical devitalization paste into the periodontium.The tooth was root canal treated before root amputation, and restored with a cuspal coverage restoration. The tooth was observed to be symptomless and functional at the one‐year follow‐up.Key learning points

Arsenic and its compounds have no place in contemporary endodontics.
Dentists should protect their patients by avoiding the use of arsenic‐containing materials and refusing to use products whose constituents are not known.
Localized bone necrosis may not require tooth extraction. Depending on the severity of the case, the tooth may be preserved by a combination of endodontic, periodontal, prosthodontic and maintenance therapies.
Stainless steel bands in endodontics: effects on cuspal flexure and fracture resistance
Authors: Pane E. S. , Palamara J. E. A. , Messer H. H. 
Published: March 2003

AbstractAims This study investigated the effect of stainless steel bands on cuspal flexure and fracture resistance of extracted maxillary premolars.Methodology Twenty extracted maxillary premolars (10 matched pairs) with mesio‐occluso‐distal (MOD) cavities and endodontic access were subjected to occlusal loading tests (100 N) using a servo‐hydraulic testing machine. Cuspal deflections were measured by an extensometer, with and without the band present. Ten teeth (one of each pair) then had the band removed, and all teeth were subjected to loading until fracture.Results Mean cuspal flexure of teeth with bands was one‐half of flexure without bands (P < 0.001). Teeth with bands fractured at higher load than their matched pairs with the band removed (P < 0.001), with mean loads at fracture of 1282 N and 729 N, respectively.Conclusions The study showed that stainless steel bands used in endodontics reduce the cuspal flexure of maxillary premolars and increase their fracture resistance.
Temporization for endodontics
Authors: Naoum H. J. , Chandler N. P. 
Published: March 2003

Abstract Naoum HJ, Chandler NP. Temporization for endodontics. International Endodontic Journal, 35, 964–978, 2002.Teeth undergoing root‐canal therapy are susceptible to microbial contamination from oral fluids both during and after treatment. With the exception of single‐visit treatment, the use of a temporary restoration is mandatory. This review aims to provide an overview of the materials and techniques used for short‐ and long‐term restorations during and immediately after endodontic treatment, and to make clinical recommendations. Further research is necessary to determine the effectiveness of temporary restorations in the conditions of the oral environment, especially with respect to leakage and functional demands.
Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 1. Intracanal drugs and substances
Authors: Hauman C. H. J. , Love R. M. 
Published: March 2003

AbstractHauman CHJ, Love RM.Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 1. Intracanal drugs and substances.International Endodontic Journal,36, 75–85, 2003.Irrigation solutions and intracanal medicaments are used within the root canal to clean and aid in disinfecting the dentinal walls. Although these materials are intended to be contained within the root canal, they invariably contact the periapical tissues, either through inadvertent extrusion through the apex or leaching. This paper is a review on the methodology involved in biocompatibility testing followed by a discussion on biocompatibility of contemporary intracanal drugs and substances used in endodontics.
The correlates and alleged biochemical background of the resazurin reduction test in semen
Authors: ZALATA  , LAMMERTIJN  , CHRISTOPHE  , COMHAIRE  
Published: March 2003

Reduction of the blue dye resazurin to pink resorufin is used to estimate the concentration of metabolically active spermatozoa in semen samples. In order to quantify the reduction of resazurin, a spectrophotometric method was developed measuring the change from blue to pink in the butanol extracted colour. The biochemical mechanisms involved in the reduction of resazurin by motile spermatozoa and seminal plasma were investigated. Addition of NADH + H+ to sperm suspension or seminal plasma increased the reduction of resazurin. The reduction reaction was inhibited by high concentrations of dicoumarol, a specific inhibitor of the diaphorase enzyme, in a dose‐dependent manner. It is suggested that the sperm diaphorase enzyme transfers electrons from NADH + H+ to resazurin, reducing it to resorufin.The degree of resazurin reduction was strongly correlated with the concentration of motile spermatozoa recovered from the 90% Percoll fraction (r = 0.98, p < 0.001). A positive correlation was also found between the reducing capacity of seminal plasma (n = 62) on the one hand, and sperm concentration (r = 0.72, p < 0.0001), progressive motility (r = 0.45, p < 0.01), normal morphology (r = 0.50, p < 0.01), and γ‐glutamyltransferase (r = 0.36, p < 0.05) on the other hand.These findings, together with our previous observations that the reduction reaction is inhibited by reactive oxygen species and polymorphonuclear white blood cells, increase our understanding of the biochemical basis of the resazurin test and may provide better insight into the interpretation of this test.