bluuebunny/crossref_metadata_2025_split huggingface dataset:
Periradicular curettage
Authors: LIN L. M. , GAENGLER P. , LANGELAND K. 
Published: September 2007

SummaryPeriradicular curettage is a part of the treatment procedure of periradicular surgery. Its main purpose is to remove pathological periradicular tissues for visibility and accessibility to facilitate the treatment of the apical root canal system, or sometimes for the removal of harmful foreign materials present in the periradicular area. Inflammatory periradicular lesions (granuloma and cysts) are the responses of the periradicular tissues to irritants from the root canal and not from the periradicular area unless medicaments and/or filling materials have been forced through the apical foramina or perforations into the periodontium. Histologically, the inflammatory periradicular lesion is similar to healing granulation tissue, which is composed of cells which have natural and specific immunological defence capability and cooperate by means of cytokines to amplify the protective mechanisms of the host. Accordingly, it is not necessary to completely curette out all the inflamed periradicular tissues during surgery, since this granulation‐like tissue will be incorporated into the new granulation tissue as part of the healing process. To control the source of irritants in the root canal is far more important than to remove all periradicular tissues affected by the irritants. The successful removal of all irritants from the root canal system results in resolution of pulpally induced periradicular lesions. In the case where the periradicular lesion is caused by endodontic instruments or cytotoxic filling materials placed in the periradicular tissues, removal of these foreign objects is required for resolution of the lesion.
Variations in the susceptibilities of components of the endodontic microflora to biomechanical procedures
Authors: GOMES B. P. F. A. , LILLEY J. D. , DRUCKER D. B. 
Published: September 2007

SummaryThe role of the endodontic micoflora in pulpal disease and in endodontic treatment failures is well established. Thus the need for effective microbial control is one of the important justifications for biomechanical procedures. However the efficacy of this stage of treatment is dependent upon the vulnerability of the involved species, which may not be uniform. The aim of this study was to investigate variations in the susceptibilities of members of the root canal microflora to routine biomechanical procedures. Forty‐two root canals were investigated microbiologically. Samples were collected before and after instrumentation and the bacterial findings were compared. In 15 cases of‘primary’root canal therapy, despite changes in the population size, no significant change in the species composition of the microflora was observed. However in 27 cases secondary’treatment, a decrease in the number of isolations of Peptostreptococcus spp. was found (P= 0.008). When all 42 cases were considered together, significant decreases were found between first and second samples for anaerobes (P= 0.0117) and for Grampositive species (P= 0.008), especially Peptostreptococcus spp. (P= 0.02). It was therefore concluded that certain species are more resistant to the biomechanical procedures than others.
An in vitro study of the coronal leakage of two root canal sealers using an obligate anaerobe microbial marker
Authors: CHAILERTVANITKUL P. , SAUNDERS W. P. , MACKENZIE D. , WEETMAN D. A. 
Published: September 2007

SummaryThe aim of this in vitro study was to investigate the coronal leakage of obligate anaerobes into root canals obturated with lateral condensation of cold guttapercha with two root canal sealers. Sixty extracted human teeth with straight, single root canals were prepared using the modified double‐flared technique with balanced force under copious irrigation until the master apical file was size 40. The teeth were divided randomly into experimental groups (40 teeth) and control groups (20 teeth). In the experimental groups, 20 teeth were obturated with lateral condensation of cold gutta‐percha and AH26 sealer and 20 teeth were obturated with the same technique using TubliSeal EWT sealer. In the control groups, 10 teeth were obturated with the same technique either with AH26 or TubliSeal EWT sealer. These teeth were completely sealed to serve as negative controls. The remaining 10 teeth were not obturated and served as positive controls. The root surface of each tooth was sealed with nail varnish except the apical 2 mm. The coronal part of each root canal was sealed with the cut end of polypropylene tube and placed in a glass bottle containing sterile Fastidious Anaerobe Broth (FAB). Aliquots of 0.5 mL of FAB were injected into the polypropylene tube and the model system was centrifuged at 168 g. An inoculum of Fusobacterium nucleatum in FAB was placed in each coronal chamber at 7‐day intervals and daily observations were made for bacterial growth in the apical reservoir for 12 weeks. All positive control teeth showed bacterial leakage within a week, while the negative control teeth remained uncon‐taminated throughout the test period. All the experimental teeth exhibited leakage of bacterial metabolites within 12 weeks, ranging from 1 to 12 weeks. The mean time for complete leakage in the AH26 and the TubliSeal EWT groups was 8.4 and 8.2 weeks respectively. There was no statistically significant difference (P > 0.05) in leakage between the AH26 and the TubliSeal EWT groups.
Microleakage of Cavit, CavitW, CavitG and IRM by impedance spectroscopy
Authors: JACQUOT B. M. , PANIGHI M. M. , STEINMETZ P. , G'SELL C. 
Published: September 2007

SummaryThe aim of this study was to quantify the sealing ability of four temporary filling materials over 9 days using a new electrochemical technique. Fifty‐two extracted human maxillary bicuspids were selected and prepared for the measurements. They were divided into four groups of 12 teeth each, in addition to two positive and two negative controls. After preparation of the endodontic access cavity the sealing ability was registered. After a randomization procedure one group was obturated with IRM, another group with Cavit, a third group with CavitW and the last group with CavitG. The sealability was measured just after obturation (time 0) and after days 1, 2, 3, 4, 7 and 9. The results showed that the IRM group was significantly more watertight than the different Cavit formulations. Throughout the experiment no significant difference was noticed between the Cavit and CavitW groups (P < 0.05). The CavitG group was significantly less watertight throughout the measurements (P < 0.05).
Rigidity and retention of carbon fibre versus stainless steel root canal posts
Authors: PURTON D. G. , LOVE R. M. 
Published: September 2007

SummaryTwo of the main requirements of a root canal post are that it is rigid so as to resist flexing under functional load, and that it is well retained in the root. This study compared these properties in two different 1‐mm diameter root canal posts–smooth carbon fibre posts (Endopost) and serrated stainless steel posts (Parapost). Ten posts of each type were tested for rigidity in a three‐point bend test. Ten posts of each type were cemented with resin cement into the roots of endodontically treated, extracted teeth. The tensile force required to remove the posts was recorded. The Paraposts proved to be significantly more rigid under load (P < 0.001) and significantly more strongly retained in the tooth roots (P < 0.005). The Parapost appears to be a mechanically superior post for the restoration of root‐filled teeth with narrow diameter root canals.
Resumed tooth development following avulsion of a permanent central incisor
Authors: GREER J. M. , MOULE A. J. , GREER P. J. 
Published: September 2007

SummaryA case is presented in which an upper right central incisor was avulsed because of trauma at age six. At the time of trauma it was suspected that the pulp had remained in the socket although the tooth had been lost. No attempt was made to treat the socket, remove the pulp, or replant the tooth. Follow‐up radiography showed that, despite initial apparent complete loss of the calcified portion of the tooth, root development proceeded to completion.
Calcium ion diffusion from calcium hydroxide‐containing materials in endodontically‐treated teeth: An in vitro study
Authors: REHMAN K. , SAUNDERS W. P. , FOYE R. H. , SHARKEY S. W. 
Published: September 2007

SummaryThe aim of this in vitro study was to determine the amount and duration of diffusion of calcium ions from both a calcium hydroxide‐containing root canal sealer and an intracanal medicament, through the apical foramen and the dentinal tubules of endodontically‐treated teeth. The root canals of 88 freshly extracted single‐rooted teeth were prepared using the modified double flared, balanced force technique with patency filing. The teeth were divided into four test groups of 20 teeth each and a control group of eight teeth. One group was dressed with a non‐setting calcium hydroxide while the other was obturated using cold lateral condensation of gutta‐percha with a calcium hydroxide‐containing sealer. An artificial root defect was created in the apical third of the root of the teeth in the other two groups and the root canals were either dressed or obturated in the same way as the first two groups. All groups were incubated at 37°C and were sampled for calcium diffusion after 1, 2 and 3 days and 1,2,3,4 and 8 weeks. There was statistically significantly more calcium diffusion with the non‐setting groups compared with the sealer groups (P < 0.05). There was more calcium ion diffusion from teeth with a patent apical foramen than those with an artificial resorptive root defect (P< 0.05).
The antimicrobial activity of endodontic sealers to anaerobic bacteria
Authors: ABDULKADER A. , DUGUID R. , SAUNDERS E. M. 
Published: September 2007

SummaryThe effect of five root canal sealers and two root canal dressing materials on the growth of three anaerobic bacteria associated with endodontic infections was determined using the agar diffusion inhibitory test. Samples of the following endodontic sealers (Apexit, Ketac‐Endo, Roth Sealer, Sealapex and Tubliseal) and root canal dressing materials (Pulpdent and Root‐cal) were incubated for 48 h with the following anaerobic bacteria: Capnocytophaga ochracea, Porphyromonas gingivalis and Peptostreptococcus micros. Statistically significant zones of bacterial growth inhibition for all the bacteria tested were observed in descending order of antimicrobial activity: Roth Sealer, Ketac‐Endo, Tubliseal, Apexit and Sealapex. Root‐cal and Pulpdent also showed statistically significant antimicrobial activity, but only to Capnocytophaga ochracea, not to the other two bacteria tested, with Pulpdent being the least active.
Root‐end cavity preparation using the MicroMega Sonic Retro‐prep Tip™. SEM analysis
Authors: LLOYD A. , JAUNBERZINS A. , DUMMER P. M. H. , BRYANT S. 
Published: September 2007

SummaryThe objective of this laboratory study was to compare root‐end cavities prepared with sonic Retro‐prep tips in a MM 1500 Sonic Air handpiece with those created by burs in a conventional handpiece. A total of 80 single‐rooted extracted human teeth with mature apices and straight canals were included in the study. Four groups of 20 extracted teeth were prepared as follows: I, a 3‐4 mm root‐end resection perpendicular to the long axis of the root, with a size 40 sonic Retro‐prep tip creating an apical cavity 3 mm into root canal system; II, a 45° bevel of the root‐face removing a 3‐4 mm root segment and root‐end preparation as per group I; III, root‐end resection as per group I, with an apical cavity prepared using a size 010 inverted cone bur 3 mm down the long axis of the root; IV, resection as per group II, followed by an apical cavity preparation with a size 010 inverted cone bur 3 mm into the root canal system. The apical root portion and root‐end cavities were replicated and prepared for SEM analysis at × 20 and × 80 magnification. The degree of chipping associated with the margin of the root‐end cavities, as evaluated with a standard grading system, and the incidence of root‐face cracks were noted. Marginal chipping of root‐end cavities prepared using sonic instrumentation was significantly worse than that produced by burs (P<0.001). Perpendicular root‐end resections showed significantly better scores than bevelled root‐end resections (P<0.005). The incidence of root‐face cracking was low with no significant difference between the experimental groups.
Cutting efficiency of Hedstrom, S and U files made of various alloys in filing motion
Authors: SCHÄFER E. , TEPEL J. 
Published: September 2007

SummaryThe cutting efficiency for sizes 25 and 35 stainless steel Hedstrom S and U files from 10 manufacturers, and titanium‐alloy Hedstrom S and U files from five manufacturers, tested for linear (filing) motion under standardized conditions were determined. Special plastic samples having well‐defined abrasive properties were used as the substrate and constant pressure was applied until the instruments were blunt. The depth of the groove achieved by filing was used to measure cutting efficiency. For both sizes there were significant differences in the cutting efficiency of files made by the various manufacturers (P < 0.001). Hedstrom files made of stainless steel, made by VDW, gave the best cutting efficiency for sizes 25 and 35. Overall, under the conditions of this study, Hedstrom files had better cutting efficiency than S or U files. Likewise, stainless steel files provided better cutting efficiency than instruments made of titanium alloys.
Intra‐canal cutting ability of MM 1500 files
Authors: LUMLEY P. J. , HARRINGTON E. , MARQUIS P. M. , WALMSLEY A. D. 
Published: September 2007

SummaryThe aims of this study were to develop a model system capable of monitoring lateral forces during root canal preparation and to measure the cutting ability of files activated by the MM 1500 sonic handpiece. Forces were monitored by a calibrated model system which utilized a combination of spring steel beams fitted with strain gauges, these were interfaced through two strain gauge amplifiers to an x‐y recorder. Single rooted canine teeth (n= 36; 32 experimental, four control) were mounted in a two‐part acrylic mould (which was an integral part of the model system) prior to sectioning horizontally 11 mm from the tooth apex. A 24 full factorial experiment with two replications was performed. Four variables were selected for evaluation, load (50 and 100 g), power (air inlet ring half or fully open), file type (Heliosonic or Shaper) and stroke rate (1 or 2 cycles per second). A new file (size 25) was used for 1 min in each canal with water irrigation. The control group was not instrumented. The cross‐sectional root canal area was measured before and after instrumentation using image analysis and increase in area was used as an indication of cutting ability. The results showed that the increase in load, power and the Shaper file all produced a significant increase in cutting ability (ANOVA, P < 0.001). However, stroke rate was not found to have a significant effect (P > 0.05). None of the interactions between the variables were significant and there was no significant difference in the control group (P > 0.05). In conclusion, this work has developed a model system to monitor lateral forces and has shown that instrument design and operator usage affect dentine removal from a root canal wall.
Comparison of three instrumentation techniques in the preparation of simulated curved root canals
Authors: ZMENER O. , BANEGAS G. 
Published: September 2007

SummaryForty‐five acrylic blocks with simulated curved canals were divided into three groups of 15 blocks each. In group 1 the canals were instrumented with ultrasoni‐cally energized K‐files (UEF) using a piezoelectric ultrasonic device. In group 2 the canals were prepared with ProFile 0.04 Taper Series 29 Rotary Instruments (PRI) in conjunction with a low‐speed high torque handpiece. In group 3 (control) the canals were hand instrumented (HI) with conventional K‐type files using a standard push‐pull circumferential technique. The efficiency of these techniques for preparing the simulated canals were compared by measuring the amount of transportation of the prepared canals at different levels from the working length using a double exposure photographic technique. A statistical analysis was used to indicate any significant difference among groups. The results showed that the use of PRI provided well‐centred and more tapered preparations. Conversely, the use of UEF and HI resulted in frequent alteration of the original curvature, showing transportation at different levels from the working length.
The sealing ability of Thermafil obturators assessed by four different microleakage techniques
Authors: PATHOMVANICH S. , EDMUNDS D. H. 
Published: September 2007

SummaryAn in vitro investigation was performed to assess the extent of apical dye leakage in relation to root fillings made by Thermafil obturators and the lateral condensation of gutta‐percha in extracted human teeth under conditions of passive dye penetration, centrifugation, a vacuum technique and an increased air pressure technique. One hundred and twenty‐eight extracted teeth were selected and prepared. The specimens were allocated into eight closely matched experimental groups. Four groups were obturated with Thermafil obturators and four with the lateral condensation technique. Microleakage was assessed after exposing one group of specimens from each of the obturation techniques to each of the four dye penetration systems using India ink as the leakage detector. The teeth were demineralized and cleared prior to examination and the maximum dye penetration for each specimen was recorded. The statistical analysis on transformed data revealed no significant differences between the four microleakage techniques and no differences between the two obturation techniques.
A comparison of stainless steel and nickel‐titanium K‐files in curved root canals
Authors: CHAN A. W. K. , CHEUNG G. S. P. 
Published: September 2007

SummaryThe purpose of this study was to determine the effects of hand instrumentation using traditional stainless steel K‐files and nickel‐titanium K‐files on the final shape of curved root canals. A total of 24 moderately curved canals in the mesial roots in extracted human mandibular first molars were randomly divided into two groups. These were instrumented manually using either stainless steel or nickel‐titanium K‐files with the step‐down technique. The cross‐sectional shape of each canal at three different horizontal levels were captured, before and after instrumentation, into a computer for comparison using image analyser software. Three parameters at each level were evaluated: (i) amount of dentine removed; (ii) least remaining dentine thicknesses on mesial and furcal aspects; and (iii) the amount and direction of canal transportation. The results showed that the two file types removed similar amounts of dentine at all three levels examined. The nickel‐titanium files left a thicker layer of dentine on both the mesial and furcal aspects than stainless steel files. However, the difference was not significant (pooled T‐test, P>0.05). Both types of files transported the centre of the canals but the nickel‐titanium instrument seemed to be safer because of the reduced amount of transportation towards the danger areas.
A scanning electron and confocal laser microscope investigation of tetracycline‐affected human dentine
Authors: LOVE R. M. , CHANDLER N. P. 
Published: September 2007

SummaryBecause of the well reported dental side‐effects of tetracycline administration, the drug should not be administered to children. However, it and its derivatives are often administered over a prolonged period for treatment of acne in young adults. Dental side effects are also noticed in these patients. The aim of this study was to examine with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) the root dentine of a tooth from a young adult affected by tetracycline therapy. The palatal root of an upper third molar, demonstrating distinct areas of tetracycline staining, was removed from the crown and sectioned longitudinally to produce two samples. The pulp tissue was peeled off the dentine and any remaining non‐mineralized tissues were removed with sodium hypochlorite. One sample was prepared for SEM and the other as a ground section which was examined with a CLSM. It was demonstrated by SEM that the mineralizing front of unaffected dentine was of a normal calcospherite appearance; in contrast, the mineralizing front of the tetracycline‐affected dentine was devoid of calcospherite formation and many surface defects were apparent. In addition, the number of dentinal tubules associated with the defects was reduced. It was shown by CLSM that tetracycline bands were made up of numerous smaller bands and that peritubular dentine not associated with fluorescent bands had incorporated tetracycline. The CLSM examination of the mineralization front of the affected dentine revealed that fluorescence of dentine was restricted to the peritubular dentine. The results confirm that dentine mineralization is affected by systemic tetracycline therapy and that tetracycline can be incorporated into peritubular dentine after mineralization of the primary dentine matrix.
Effectiveness of the Canal Finder and hand instrumentation in removal of gutta‐percha root fillings during root canal retreatment
Authors: IMURA N. , ZUOLO M. L. , FERREIRA M. O. F. , NOVO N. F. 
Published: September 2007

SummaryThe purpose of this study was to quantify the amount of remaining gutta‐percha/sealer on the canal walls when the Canal Finder system, hand instrumentation and a combination of both (hybrid technique) were used to remove these materials. The amount of apically‐extruded debris and the time required for removal were also recorded. Sixty extracted maxillary anterior teeth were prepared using a stepback technique and obturated with gutta‐percha. Reinstrumentation of all groups was done in conjunction with a solvent, chloroform. The teeth were split longitudinally and photographed, and the total area of the root canal and the area of the debris were traced and quantified using a computerized image analysis system. The ratio of remaining obturation material to root canal surface was derived and analysed statistically. Hand instrumentation resulted in less debris remaining than did the other two techniques (P<0.05). The differences in the amount of apically extruded debris were not significant among the techniques (P > 0.05). The hybrid technique required significantly less time for filling material removal. The Canal Finder system alone was not superior to hand instrumentation.